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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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15 pages, 1964 KiB  
Article
Synthesis of 2,3-Dihydrobenzofuran Chalcogenides Under Visible Light: A Sustainable Approach
by Luana S. Gomes, Millena C. Silva, Patrick C. Nobre, Thiago J. Peglow and Vanessa Nascimento
Processes 2025, 13(4), 1038; https://doi.org/10.3390/pr13041038 - 31 Mar 2025
Viewed by 283
Abstract
This study introduces a visible light-mediated synthesis of 2,3-chalcogenil-dihydrobenzofuran through the oxyselenocyclization of 2-allylphenols in the presence of chalcogenides. Emphasizing sustainability, this method is notably enhanced by proceeding under mild conditions, facilitated by a straightforward I2/SnCl2 as a promoter and [...] Read more.
This study introduces a visible light-mediated synthesis of 2,3-chalcogenil-dihydrobenzofuran through the oxyselenocyclization of 2-allylphenols in the presence of chalcogenides. Emphasizing sustainability, this method is notably enhanced by proceeding under mild conditions, facilitated by a straightforward I2/SnCl2 as a promoter and blue LED irradiation to activate the process. A variety of functional groups were effectively tolerated under our developed approach, leading to the desired products with yields ranging from good to excellent, demonstrating in this way the versatility of the method. In addition, the synthesized compounds were characterized using 1H and 13C NMR techniques. Full article
(This article belongs to the Special Issue Advances and Prospects in Organic Synthesis)
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16 pages, 8022 KiB  
Article
Injection-Molded Poly(butylene succinate)/Wheat Flour By-Product Biocomposites: Mechanical, Thermal, and Structural Characterization
by Bianca Peron-Schlosser, Rúbia Martins Bernardes Ramos, Luana Cristina Paludo, Pablo Inocêncio Monteiro, Fabíola Azanha de Carvalho, Samuel Camilo da Silva, Bruno Alexandro Bewzenko Cordova, Benjamim de Melo Carvalho, Fabio Yamashita and Michele Rigon Spier
Processes 2025, 13(4), 1044; https://doi.org/10.3390/pr13041044 - 31 Mar 2025
Viewed by 218
Abstract
The increasing concern regarding the environmental impact of conventional plastics has intensified the search for sustainable alternatives. This study investigated the development and characterization of biocomposites produced from glue flour (GF), a wheat milling by-product, and poly(butylene succinate) (PBS) using injection molding. GF/PBS [...] Read more.
The increasing concern regarding the environmental impact of conventional plastics has intensified the search for sustainable alternatives. This study investigated the development and characterization of biocomposites produced from glue flour (GF), a wheat milling by-product, and poly(butylene succinate) (PBS) using injection molding. GF/PBS ratios of 100/0 (PBS0), 80/20 (PBS20), 70/30 (PBS30), and 60/40 (PBS40) (w/w) were evaluated in terms of physical, mechanical, and thermal properties. The results showed that increasing the PBS content significantly enhanced tensile strength from 1.36 MPa (PBS0) to 12.23 MPa (PBS40) and Young’s modulus from 0.12 MPa to 1.54 MPa. Water solubility decreased from 37.03% (PBS0) to 16.08% (PBS40), and linear shrinkage was reduced from 5.5% (PBS0) to around 2.0% (PBS40). Scanning electron microscopy (SEM) analysis revealed improved homogeneity and reduced granule visibility with higher PBS concentration. Fourier transform infrared spectroscopy (FTIR) spectra indicated intensified interactions between starch, proteins, and PBS as its content in the formulation increased. Thermal analysis revealed that biocomposites containing PBS exhibited well-defined melting (Tm ~115 °C) and crystallization (Tc ~80 °C) temperatures, indicating more consistent thermal behavior than the PBS-free sample. These findings suggest that GF/PBS biocomposites have strong potential as sustainable alternatives to conventional plastics, offering viable applications across various industrial sectors. Full article
(This article belongs to the Section Materials Processes)
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28 pages, 4379 KiB  
Article
Linking Catalyst Development and Chemical Reactor Design with Ethanol to Butadiene Processes
by Alexandre C. Dimian, Grigore Bozga and Ionut Banu
Processes 2025, 13(4), 1024; https://doi.org/10.3390/pr13041024 - 29 Mar 2025
Viewed by 359
Abstract
This study explores the relation between catalyst research and chemical reaction engineering for developing ethanol to butadiene (ETB) technologies. An ETB process involves two distinct steps: ethanol dehydrogenation to acetaldehyde and butadiene synthesis. The catalyst functions can be tailored separately or imbedded in [...] Read more.
This study explores the relation between catalyst research and chemical reaction engineering for developing ethanol to butadiene (ETB) technologies. An ETB process involves two distinct steps: ethanol dehydrogenation to acetaldehyde and butadiene synthesis. The catalyst functions can be tailored separately or imbedded in a single formulation, leading to two-stage and one-stage processes. The performance of selected ETB catalysts is confronted with predictions based on chemical equilibrium, considering the simultaneous formation of products, by-products and impurities. The analysis shows that, essentially, the performance of ETB catalysts is controlled by kinetic factors. A shortlist of relevant catalysts for industrial implementation is proposed. The analysis highlights two key issues for industrial reactor design: catalyst deactivation/regeneration and the use of inert gas as a major process cost. The first issue is addressed by developing a comprehensive fluidized bed reactor model operating in the bubbling regime, capable of handling complex reaction kinetics. Good performance close to plug flow is obtained with bubbles at a size of 4 to 8 cm and with intensive mass transfer. The simulation reveals an autocatalytic effect of acetaldehyde on the butadiene formation favored by a well-mixed dense phase. The second study investigates the optimization of the chemical reaction section in a reactor–separation–recycle system via economic potential. The costs associated with the catalytic reactor and the catalyst charge, including regeneration, along with the costs of recycling reactants and of an inert gas if used, are key factors in determining the optimal operation region. This approach, verified by simulation in Aspen PlusTM, points out that better robustness and a limited use of an inert gas are necessary for developing industrial catalysts for the one-stage ETB process. Full article
(This article belongs to the Special Issue Industrial Chemistry Reactions (3rd Edition): Kinetics, Mass and Heat Transfer in View of the Industrial Reactors Design)
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11 pages, 2912 KiB  
Article
Bacterial-Retted Hemp Fiber/PLA Composites
by Lee M. Smith, Yu Fu, Raj Kumar Pittala, Xun Wang, Chloe Jabel, Kelvin Masignag, Josue Arellanes, Mahan Ghosh, Sheldon Q. Shi, Melanie Ecker and Cuicui Wang
Processes 2025, 13(4), 1000; https://doi.org/10.3390/pr13041000 - 27 Mar 2025
Viewed by 298
Abstract
The push for sustainability in all facets of manufacturing has led to an increased interest in biomass as an alternative to non-renewable materials. Hemp bast fiber mats were produced from a bacterial retting process, named BFM, as the fiber reinforcement. The objective of [...] Read more.
The push for sustainability in all facets of manufacturing has led to an increased interest in biomass as an alternative to non-renewable materials. Hemp bast fiber mats were produced from a bacterial retting process, named BFM, as the fiber reinforcement. The objective of this study was to evaluate the feasibility of laminating BFM with polylactic acid (PLA) for a composite panel product. Since both BFM and PLA are biodegradable, the resulting BFM-PLA composites will be 100% biodegradable. PLA pallets were processed into thin polymer sheets which served as the matrix. The BFM and PLA plates were laminated in five layers and compression-molded into composite panels. Experiments were conducted on the three BFM-to-PLA ratios (35/65, 45/55, and 50/50). Mechanical properties (tensile and bending properties) and physical properties (thickness swell and water absorption) were tested and compared to the currently commercial sheet molding compound (SMC) from fiber glass. The thermal behavior of the BFM/PLA composites was characterized using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). The developed BFM/PLA composite product is a sustainable alternative to existing synthetical fiber-reinforced polymer (FRP) that is biodegradable in landfill at the end of life. Full article
(This article belongs to the Special Issue Bioprocess Engineering: Sustainable Manufacturing for a Green Society)
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15 pages, 3984 KiB  
Article
Terpene-Based Biofuel Additives (Citral, Limonene, and Linalool) with Chloroform: Experimental and Modeling Study of Volumetric and Transport Properties
by Nikola Grozdanić, Mirjana Kijevčanin and Ivona Radović
Processes 2025, 13(4), 974; https://doi.org/10.3390/pr13040974 - 25 Mar 2025
Viewed by 229
Abstract
In this paper, the thermodynamic properties of terpene mixtures were investigated because they represent a promising group of compounds, usually extracted from biomass, with their most notable application as fuel performance enhancers. The densities, viscosities, refractive indices, and ultrasonic speeds of sound were [...] Read more.
In this paper, the thermodynamic properties of terpene mixtures were investigated because they represent a promising group of compounds, usually extracted from biomass, with their most notable application as fuel performance enhancers. The densities, viscosities, refractive indices, and ultrasonic speeds of sound were measured for three binary mixtures, citral + chloroform, limonene + chloroform, and linalool + chloroform, across the full composition range at temperatures between 288.15 K and 323.15 K under atmospheric pressure. Using experimental data, excess molar volumes, viscosity deviations, refractive index deviations, and isentropic compressibility, deviations were calculated. Additionally, properties such as partial molar volumes, excess partial molar volumes, partial molar volumes at infinite dilution, and apparent molar volumes were derived. The excess and deviation properties were analyzed using the Redlich–Kister equation. A single mathematical model, the Heric–Brewer–Jouyban–Acree model, was used to represent densities, viscosities, refractive indices, and ultrasonic speeds of sound. The results obtained in this work suggest that dispersive interactions dominate in the limonene and linalool binary mixtures, while hydrogen bonding plays a significant role in the citral + chloroform system. In summary, dispersive interactions are dominant in nonpolar systems like limonene and linalool, while hydrogen bonding significantly affects the citral-chloroform mixture, where the polar groups in citral interact with chloroform molecules. These differences in intermolecular forces help explain the distinct behavior of each mixture. The modeling outcomes demonstrated that the Heric–Brewer–Jouyban–Acree model accurately correlated the experimental thermodynamic properties, with average percent deviations below 1% for all three systems. Full article
(This article belongs to the Special Issue Experimental Investigation and Modeling of Biowaste Conversion into Renewable Energy and Resources)
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30 pages, 5789 KiB  
Article
Fischer–Tropsch Biofuel Production from Supercritical Water Gasification of Lignocellulosic Biomass: Process Modelling and Life-Cycle Assessment
by Dimitrios Katsourinis, Dimitrios Giannopoulos and Maria Founti
Processes 2025, 13(3), 895; https://doi.org/10.3390/pr13030895 - 18 Mar 2025
Viewed by 307
Abstract
The production of Fischer–Tropsch liquid biofuels from the supercritical water gasification (SCWG) of lignocellulosic biomass is energetically and environmentally assessed by coupling process modelling with Life-Cycle Assessment. A conceptual process model has been developed comprising the following stages: (a) the thermochemical conversion of [...] Read more.
The production of Fischer–Tropsch liquid biofuels from the supercritical water gasification (SCWG) of lignocellulosic biomass is energetically and environmentally assessed by coupling process modelling with Life-Cycle Assessment. A conceptual process model has been developed comprising the following stages: (a) the thermochemical conversion of lignocellulosic biomass in a supercritical water gasification (SCWG) reactor, (b) syngas upgrade through dry reforming (DRR), (c) liquid biofuel production from Fischer–Tropsch synthesis (FTS) and (d) FT product upgrade and refinement, so that diesel-like (FT—Diesel), gasoline-like (FT—Gasoline), and jet fuel-like (FT Jet Fuel) yields are predicted. Parametric studies have been performed, highlighting the effect of biomass concentration and SCWG temperature on end-product yields. Furthermore, alternative scenarios have been examined with respect to: (a) maximizing FT liquid biofuel yields and (b) minimizing heat requirements to potentially achieve a thermally self-sustained process. The results of the simulated process, including liquid biofuel yield and heat-demand predictions, are used as inputs in the inventories compiled for the Life-Cycle Assessment of the overall process. Agricultural and feedstock transportation stages have also been considered. Energetic and environmental benefits and challenges are highlighted through the quantification of Global Warming Potential (GWP), while special importance is assigned to following the REDII sustainability methodology and reference data. Full article
(This article belongs to the Special Issue Processes in Biofuel Production and Biomass Valorization)
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13 pages, 1658 KiB  
Article
The Effect of Agitation and the Use of Perfluorodecalin on Lipase Production by Yarrowia lipolytica in a Bioreactor
by Filipe Smith Buarque, Roseli Lopes da Silva, Ana Iraidy Santa Brígida, Priscilla Amaral and Maria Alice Zarur Coelho
Processes 2025, 13(3), 865; https://doi.org/10.3390/pr13030865 - 15 Mar 2025
Viewed by 435
Abstract
Lipase production by the strictly aerobic yeast Yarrowia lipolytica is closely related to the content of dissolved oxygen in the culture medium. Some strategies to improve oxygen transfer to microorganisms have already been used, such as the use of perfluorocarbons (PFCs). The present [...] Read more.
Lipase production by the strictly aerobic yeast Yarrowia lipolytica is closely related to the content of dissolved oxygen in the culture medium. Some strategies to improve oxygen transfer to microorganisms have already been used, such as the use of perfluorocarbons (PFCs). The present work investigates the influence of agitation speed and the use of perfluorodecalin (PFC) on the profile of the produced lipases. Lipase production increased 2.5-fold with a higher agitation speed (550 to 650 rpm) without PFCs in the medium. The presence of an oxygen carrier led to a significant 91% increase in lipase production at lower shaking speeds compared to the assay without PFC; however, an increase in lipase production was not detected with PFC at 650 rpm. The protein profiles exhibited typical bands for two lipases produced (near 40 and 60 kDa), and these bands became more intense when PFC was added during production, as a result of the large enhancement in lipolytic activity. Additionally, the protein profiles obtained from extracts at 650 rpm were clearer and more selective regardless of the presence of PFC, suggesting an enhancement in specific activity associated with increased shaking. These findings highlight the significant impact of oxygen availability on lipase production, offering valuable insights for industrial applications. Full article
(This article belongs to the Special Issue Green Solvent for Separation and Extraction Processes)
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53 pages, 4254 KiB  
Review
The Occurrence of Micropollutants in the Aquatic Environment and Technologies for Their Removal
by Meilia Tarigan, Samir Raji, Heyam Al-Fatesh, Peter Czermak and Mehrdad Ebrahimi
Processes 2025, 13(3), 843; https://doi.org/10.3390/pr13030843 - 13 Mar 2025
Cited by 1 | Viewed by 523
Abstract
The presence of micropollutants in aquatic environments is an increasing global concern due to their persistence and potential harmful effects on aquatic organisms. Among the most concerning of these micropollutants are microplastics, pharmaceutical compounds, personal care products, and industrial chemicals, posing a significant [...] Read more.
The presence of micropollutants in aquatic environments is an increasing global concern due to their persistence and potential harmful effects on aquatic organisms. Among the most concerning of these micropollutants are microplastics, pharmaceutical compounds, personal care products, and industrial chemicals, posing a significant threat to human health and aquatic ecosystems. This issue is further exacerbated by the diverse sources and complex physicochemical properties of micropollutants, as well as the inability of conventional water and wastewater treatment systems to effectively remove these contaminants. The removal of micropollutants is therefore becoming increasingly important, leading to extensive research into various physicochemical, biological, and hybrid treatment methods aimed at minimizing their environmental impact. This review examines the classification, occurrence, and associated environmental and health risks of commonly detected micropollutants in aquatic systems. Additionally, it provides an overview of advanced treatment methods being developed to implement a fourth purification stage in wastewater treatment plants. Biological, chemical, physical, and hybrid purification technologies are critically reviewed, with a focus on their performance characteristics and potential applications. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
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17 pages, 4763 KiB  
Article
An Analysis of a Cement Hydration Process Using Glass Waste from Household Appliances as a Supplementary Material
by Karolina Bekerė, Jurgita Malaiškienė and Jelena Škamat
Processes 2025, 13(3), 840; https://doi.org/10.3390/pr13030840 - 13 Mar 2025
Viewed by 480
Abstract
Due to the significant increase in consumerism, the amount of household appliance waste has been growing, particularly in the form of glass. This study explores the possibility of using this glass (HAGw) as a replacement additive in cement-based products. The article examines the [...] Read more.
Due to the significant increase in consumerism, the amount of household appliance waste has been growing, particularly in the form of glass. This study explores the possibility of using this glass (HAGw) as a replacement additive in cement-based products. The article examines the properties of HAGw, including its chemical composition (XRF), mineral composition (XRD), particle morphology, and size distribution. Scanning electron microscopy (SEM) analysis revealed that HAGw particles could partially crystallise, forming needle-shaped minerals. When replacing 10%, 20%, and 30% of cement with dispersive HAGw, the rate of cement hydration remains unchanged; however, the amount of heat released decreases proportionally to the amount of waste used. Thermogravimetric analysis indicated that substituting a part of the cement with HAGw reduces the amount of portlandite over longer curing periods, indicating the pozzolanic activity of the glass, while the quantity of calcium silicate hydrates (C-S-H) remains similar to the control sample. In the microstructure of the samples, numerous agglomerates of glass particles are formed, increasing the porosity of the cement matrix and reducing its strength. However, over time, the surface of the glass particles begins to dissolve, leading to the formation of new cement hydrates that gradually fill the voids. This process enhances cement density, increases the ultrasonic pulse velocity, and improves compressive strength, particularly after 90 days, compared to the properties of the samples at 7 and 28 days of curing. Full article
(This article belongs to the Special Issue Green Chemistry: From Wastes to Value-Added Products (2nd Edition))
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26 pages, 655 KiB  
Review
A Comprehensive Survey on Advanced Control Techniques for T-S Fuzzy Systems Subject to Control Input and System Output Requirements
by Wen-Jer Chang, Yann-Horng Lin and Cheung-Chieh Ku
Processes 2025, 13(3), 792; https://doi.org/10.3390/pr13030792 - 9 Mar 2025
Viewed by 906
Abstract
This paper provides a comprehensive survey on advanced control techniques for Takagi-Sugeno (T-S) fuzzy systems that are subject to input and output performance constraints. The focus is on addressing practical applications, such as actuator saturation and output limits, which are often encountered in [...] Read more.
This paper provides a comprehensive survey on advanced control techniques for Takagi-Sugeno (T-S) fuzzy systems that are subject to input and output performance constraints. The focus is on addressing practical applications, such as actuator saturation and output limits, which are often encountered in industries like aerospace, automotive, and robotics. The paper discusses key control methods such as model predictive control, anti-windup compensators, and Linear Matrix Inequality (LMI)-based control, emphasizing their effectiveness in handling input and output constraints. These techniques ensure system stability, robustness, and performance even under strict physical limitations. The survey also highlights the importance of T-S fuzzy systems, which provide a flexible framework for modeling and controlling nonlinear systems by breaking them down into simpler linear models. Additionally, recent developments in robust and adaptive control strategies are explored, particularly in handling time delays, disturbances, and uncertainties. These methods are crucial for real-time applications where the system must remain stable and safe despite unmeasured states or external disturbances. By reviewing these advanced techniques, the paper aims to identify research gaps and future directions, particularly in scalable solutions and integrating data-driven approaches with T-S fuzzy control frameworks. Full article
(This article belongs to the Special Issue Fuzzy Control System: Design and Applications)
12 pages, 3362 KiB  
Article
Scalable and Contamination-Free Selenium-Assisted Exfoliation of Transition Metal Dichalcogenides WSe2 and MoSe2
by Rehan Younas, Guanyu Zhou and Christopher L. Hinkle
Processes 2025, 13(3), 791; https://doi.org/10.3390/pr13030791 - 8 Mar 2025
Viewed by 1209
Abstract
In two-dimensional (2D) materials research, exfoliating 2D transition metal dichalcogenides (TMDs) from their growth substrates for device fabrication remains a significant challenge. Current methods, such as those involving polymers, metals, or chemical etchants, suffer from limitations like contamination, defect introduction, and a lack [...] Read more.
In two-dimensional (2D) materials research, exfoliating 2D transition metal dichalcogenides (TMDs) from their growth substrates for device fabrication remains a significant challenge. Current methods, such as those involving polymers, metals, or chemical etchants, suffer from limitations like contamination, defect introduction, and a lack of scalability. Here, we demonstrate a selenium capping-based exfoliation technique. Its advantage lies in its ability to enable the clean, contamination-free exfoliation and transfer of TMD films. We successfully exfoliated and transferred monolayer and multilayer TMD films, including WSe2 and MoSe2. The selenium capping layer not only enables seamless exfoliation but also protects the film from oxidation, as confirmed by X-ray photoelectron spectroscopy and Raman spectroscopy. This approach is versatile and applicable to a range of TMDs and thicknesses, paving the way for the high-quality, scalable integration of 2D materials into nanoelectronic devices. Full article
(This article belongs to the Special Issue Advancements in Low-Dimensional Materials: Focus on Detailed Methodologies)
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12 pages, 1668 KiB  
Article
Deep Drawing of Paperboard Under Heat–Moisture Control
by Julia Orlik, Viacheslav Khilkov, Stefan Rief, Holger Schubert, Marek Hauptmann and Heiko Andrä
Processes 2025, 13(3), 780; https://doi.org/10.3390/pr13030780 - 7 Mar 2025
Viewed by 401
Abstract
Deep drawing is a common process for shaping paperboard packages. To improve performance, the paperboard is kept in a room with high humidity before treatment. The surfaces of forming tools that come into contact with the paperboard are heated. A control problem for [...] Read more.
Deep drawing is a common process for shaping paperboard packages. To improve performance, the paperboard is kept in a room with high humidity before treatment. The surfaces of forming tools that come into contact with the paperboard are heated. A control problem for heating moist paperboard, with evaporation from the pore surface, is considered in this paper. Micro-CT images of three different paperboards are taken, segmented, and parameterized with respect to the specific pore surface in terms of the pore surface per pore volume, pore volume fraction, fiber thickness, average surface contact area between fibers, and unsupported fiber length. Simple averaging formulas are provided to compute the effective coefficients in the coupled water-diffusion and heat-transfer problem with a phase transition. The model is validated by experimental measurements and offers an opportunity for optimal heating control to simultaneously ensure compliance of the paperboard layer, leading to small delamination at its boundary, thereby avoiding folding. Full article
(This article belongs to the Special Issue Advanced Heat Transfer Technologies for the Design, Operation and Optimization of Steam Power Systems)
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20 pages, 3339 KiB  
Article
Experimental Dielectric Properties and Temperature Measurement Analysis to Assess the Thermal Distribution of a Multimode Microwave-Assisted Susceptor Fixed-Bed Reactor
by Alejandro Fresneda-Cruz, Gonzalo Murillo-Ciordia and Ignacio Julian
Processes 2025, 13(3), 774; https://doi.org/10.3390/pr13030774 - 7 Mar 2025
Viewed by 458
Abstract
In this study, the integration of microwave-assisted technology into fixed-bed configuration processes is explored aiming to characterize and address its challenges with a customized multimodal microwave cavity. This research focuses on evaluating the uncertainty in contactless temperature measurement methods as spectral thermographic cameras [...] Read more.
In this study, the integration of microwave-assisted technology into fixed-bed configuration processes is explored aiming to characterize and address its challenges with a customized multimodal microwave cavity. This research focuses on evaluating the uncertainty in contactless temperature measurement methods as spectral thermographic cameras and infrared pyrometers, microwave heating performance, and the thermal homogeneity within fixed beds containing microwave–susceptor materials, including the temperature-dependent dielectric characterization of such materials, having different geometry and size (from 120 to 5000 microns). The thermal inhomogeneities along different bed configurations were quantified, assessing the most appropriate fixed-bed arrangement and size limitation at the employed irradiation frequency (2.45 GHz) to tackle microwave-assisted gas–solid chemical conversions. An increased temperature heterogeneity along the axial profile was found for finer susceptor particles, while the higher microwave susceptibility of coarser grades led to increased temperature gradients, ΔT > 300 °C. Moreover, results evidenced that the temperature measurement on the fixed-bed quartz reactor surface by a punctual infrared pyrometer entails a major error regarding the real temperature on the microwave susceptor surface within the tubular quartz reactor (up to 230% deviation). The experimental findings pave the way to assess the characteristics that microwave susceptors and fixed beds must perform to minimize thermal inhomogeneities and optimize the microwave-assisted coupling with solid–gas-phase reactor design and process upscaling using such multimode cavities. Full article
(This article belongs to the Special Issue Heat and Mass Transfer Phenomena in Energy Systems)
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18 pages, 3764 KiB  
Article
Conversion of Glass Waste into Zeolite A Adsorbent for Efficient Ammonium Ion Adsorption from Aqueous Solution: Kinetic and Isotherm Studies
by Neysa Pereyra, Urooj Kamran, Wilson Aguilar-Mamani and Farid Akhtar
Processes 2025, 13(3), 678; https://doi.org/10.3390/pr13030678 - 27 Feb 2025
Viewed by 705
Abstract
In this study, a zeolitic adsorbent (AGW-ZA) was successfully developed from glass waste (GW)-derived aluminosilicates. The GW, serving as the starting material, underwent alkaline activation and hydrothermal treatment to yield the AGW-ZA adsorbent, which exhibited a surface area of 216.48 m2/g. [...] Read more.
In this study, a zeolitic adsorbent (AGW-ZA) was successfully developed from glass waste (GW)-derived aluminosilicates. The GW, serving as the starting material, underwent alkaline activation and hydrothermal treatment to yield the AGW-ZA adsorbent, which exhibited a surface area of 216.48 m2/g. The AGW-ZA demonstrated significantly higher ammonium (NH4+) ion adsorption (142.5 mg/g at 1000 mg/L) than pristine GW (80.0 mg/g). Optimal adsorption experimental parameters were identified (0.1 g dosage, pH = 7, and 10 h contact time) to determine the maximum NH4+ ions’ adsorption potential by adsorbents. Kinetic and isotherm models were applied to experimental data to describe the adsorption mechanisms. The pseudo-second-order model provided the best fit for both AGW-ZA and pristine GW, indicating that the adsorption process is followed by chemical interaction via ion exchange. Regarding isotherms, the Freundlich model was most suitable for AGW-ZA, signifying that NH4+ ions adsorbed on heterogeneous adsorbent surfaces by forming multilayers, while the Temkin model fit the pristine GW data, indicating the chemisorption nature with medium adsorbate–adsorbent interactions above the heterogeneous surface. This study explores the potential of transforming discarded GW into a high-performance zeolitic adsorbent for the mitigation of environmental pollution by removing NH4+ ions from wastewater while simultaneously addressing waste management challenges. Full article
(This article belongs to the Special Issue Novel Applications of Zeolites in Adsorption Processes)
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28 pages, 2347 KiB  
Review
Mechanistic Aspects of the Chemical Reactions in a Three-Way Catalytic Converter Containing Cu and Platinum Group Metals
by Christos Papadopoulos, Marios Kourtelesis, Athanasios Dimaratos, Anastasia Maria Moschovi, Iakovos Yakoumis and Zissis Samaras
Processes 2025, 13(3), 649; https://doi.org/10.3390/pr13030649 - 25 Feb 2025
Viewed by 749
Abstract
Strict gaseous emission standards are applied globally to regulate the maximum amounts of pollutant emissions that can be produced from all vehicles. The exhaust aftertreatment systems used by automotive manufacturers rely on the utilization of precious metals (Pt, Pd, Rh). However, much effort [...] Read more.
Strict gaseous emission standards are applied globally to regulate the maximum amounts of pollutant emissions that can be produced from all vehicles. The exhaust aftertreatment systems used by automotive manufacturers rely on the utilization of precious metals (Pt, Pd, Rh). However, much effort has been devoted on the reduction or the replacement of the amount of Platinum Group Metals (PGMs) in three-way catalysts (TWC), both from a cost-effectiveness as well as an environmental point of view. PROMETHEUS catalyst, which was recently homologated for Euro 6 applications, is a low-cost, Cu-based TWC, which consists of a significantly lower quantity of PGMs compared to conventional state-of-the-art catalysts and achieves similar or even better catalytic efficiencies. In this review paper, a complex reaction scheme is proposed for the first time for a catalytic converter utilizing Cu and PGMs, following an extensive literature investigation of the available models. The scheme also accounts for the surface reaction mechanisms of the main processes and the side reactions potentially taking place during the TWC operation in the presence of Cu and at least one of the following PGMs: Pt, Pd or Rh. At a next step, the proposed reaction scheme will be validated based on experimental data, using mathematical modelling of a PROMETHEUS catalytic converter incorporating Cu and PGM nanoparticles. Full article
(This article belongs to the Special Issue Advances in Supported Nanoparticle Catalysts (Volume II))
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24 pages, 10667 KiB  
Article
An Investigation of MnOx and K/MnOx-Based Catalysts on MnO2 and Fe3O4 Supports for the Deep Oxidation of Cyclohexane
by Md Sarwar Kamal, Catherine B. Almquist and David L. Tierney
Processes 2025, 13(3), 634; https://doi.org/10.3390/pr13030634 - 24 Feb 2025
Viewed by 1071
Abstract
K/MnOx catalysts on MnO2 and Fe3O4 supports were synthesized and compared for the deep oxidation of cyclohexane. The presence of potassium (K) on the catalysts enhanced the catalytic activity compared to catalysts with similar composition but without K. [...] Read more.
K/MnOx catalysts on MnO2 and Fe3O4 supports were synthesized and compared for the deep oxidation of cyclohexane. The presence of potassium (K) on the catalysts enhanced the catalytic activity compared to catalysts with similar composition but without K. Interestingly, the lowest loading of K/MnOx used in this study (0.63 mmoles/g support) performed better than those with higher loadings. The presence of K on the catalysts increased water adsorption, decreased the extent of sintering, and inhibited changes in crystal phase of the catalyst support, as evidenced by TGA, XRD, and BET surface area analyses. The XRD profiles of the catalysts showed mixed crystal phases of MnOx and FeOx species, and EPR results support the presence of mixed valence states of Fe and Mn. The activation energies for MnOx-supported catalysts and FeOx-supported catalysts were approximately 50 kJ/mole and 53 kJ/mole, respectively. Full article
(This article belongs to the Special Issue Metal Oxides in Heterogeneous Oxidation Catalysis)
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21 pages, 1959 KiB  
Article
Energy Storage and Management of Offshore Wind-Based Green Hydrogen Production
by Isabella Pizzuti, Michela Conti, Giovanni Delibra, Alessandro Corsini and Alessio Castorrini
Processes 2025, 13(3), 643; https://doi.org/10.3390/pr13030643 - 24 Feb 2025
Viewed by 1087
Abstract
The coupling of offshore wind energy with hydrogen production involves complex energy flow dynamics and management challenges. This study explores the production of hydrogen through a PEM electrolyzer powered by offshore wind farms and Lithium-ion batteries. A digital twin is developed in Python [...] Read more.
The coupling of offshore wind energy with hydrogen production involves complex energy flow dynamics and management challenges. This study explores the production of hydrogen through a PEM electrolyzer powered by offshore wind farms and Lithium-ion batteries. A digital twin is developed in Python with the aim of supporting the sizing and carrying out a techno-economic analysis. A controller is designed to manage energy flows on an hourly basis. Three scenarios are analyzed by fixing the electrolyzer capacity to meet a steel plant’s hydrogen demand while exploring different wind farm configurations where the electrolyzer capacity represents 40%, 60%, and 80% of the wind farm. The layout is optimized to account for the turbine wake. Results reveal that when the electrolyzer capacity is 80% of the wind farm, a better energy balance is achieved, with 87.5% of the wind production consumed by the electrolyzer. In all scenarios, the energy stored is less than 5%, highlighting its limitation as a storage solution in this application. LCOE and LCOH differ minimally between scenarios. Saved emissions from wind power reach 268 ktonCO2/year while those from hydrogen production amount to 520 ktonCO2/year, underlying the importance of hydrogen in hard-to-abate sectors. Full article
(This article belongs to the Special Issue Sustainable Hydrogen Production Processes)
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34 pages, 7234 KiB  
Article
Machine Learning Predictions for the Comparative Mechanical Analysis of Composite Laminates with Various Fibers
by Baha Eddine Ben Brayek, Sirine Sayed, Viorel Mînzu and Mostapha Tarfaoui
Processes 2025, 13(3), 602; https://doi.org/10.3390/pr13030602 - 20 Feb 2025
Cited by 1 | Viewed by 604
Abstract
This article addresses the complex behavior of composite laminates under varied layer orientations during tensile tests, focusing on carbon fiber and epoxy matrix composites. Data characterizing the mechanical load behavior are obtained using twelve composite laminates with different layer orientations and the DIGIMAT-VA [...] Read more.
This article addresses the complex behavior of composite laminates under varied layer orientations during tensile tests, focusing on carbon fiber and epoxy matrix composites. Data characterizing the mechanical load behavior are obtained using twelve composite laminates with different layer orientations and the DIGIMAT-VA software (version 2023.3). First, these data were used to elaborate a complex comparative analysis of composite laminates from the perspective of materials science. Composite laminates belong to three classes: unidirectional, off-axis oriented, and symmetrically balanced laminates, each having a specific behavior. From the perspective of designing a new material, a prediction model that is faster than the finite element analysis is needed to apply this comparative analysis’s conclusions. As a novelty, this paper introduces several machine learning prediction models for composite laminates with 16 layers arranged in different orientations. The Regression Neural Network model performs best, effectively replacing expensive tensile test simulations and ensuring good statistics (RMSE = 34.385, R2 = 1, MAE = 19.829). The simulation time decreases from 34.5 s (in the case of finite element) to 0.6 s. The prediction model returns the stress–strain characteristic of the elastic zone given the new layer orientations. These models were implemented in the MATLAB system 2024, and their running proved good models’ generalization power and accuracy. Even specimens with randomly oriented layers were successfully tested. Full article
(This article belongs to the Special Issue Application of Artificial Intelligence in Industrial Process Modelling and Optimization)
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12 pages, 1124 KiB  
Article
Evaluation of Semi-Continuous Anaerobic Fermentation of Alperujo by Methanogenesis Inhibition
by Elena Jiménez-Páez, Antonio Serrano, Rafael Hueso, Fernando G. Fermoso and Juan Cubero-Cardoso
Processes 2025, 13(3), 600; https://doi.org/10.3390/pr13030600 - 20 Feb 2025
Viewed by 360
Abstract
Two methanogenesis inhibition strategies for enhancing volatile fatty acid (VFA) production through the anaerobic fermentation of alperujo, a byproduct of olive oil production, were evaluated. Methanogenesis inhibition was implemented via two different approaches, one by pH adjustment to 5.0 and another one by [...] Read more.
Two methanogenesis inhibition strategies for enhancing volatile fatty acid (VFA) production through the anaerobic fermentation of alperujo, a byproduct of olive oil production, were evaluated. Methanogenesis inhibition was implemented via two different approaches, one by pH adjustment to 5.0 and another one by chemical inhibition using 2-bromoethanesulfonate (BES) at pH 7. The VFA accumulation at the end of the experiment was 67% higher under the BES condition than under the pH 5 condition. Interestingly, the VFA profiles were similar under both conditions, with acetic acid as the dominant product, followed by propionic and butyric acids. The results demonstrated a 25% increase in alperujo solubilization under the BES condition, compared to under the pH 5 condition. This latest finding, together with the similar VFA profiles on both strategies, suggests that the hydrolysis step in alperujo solubilization was impacted by the pH difference. These findings highlight the effectiveness of chemical inhibition in enhancing solubilization, hydrolysis, and VFA accumulation during anaerobic fermentation of alperujo and, most importantly, the negative effect of pH 5 on the solubilization step. Full article
(This article belongs to the Special Issue Overview, Challenges and Current Trends in H2 Energy, Gasification, Waste and Biomass)
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21 pages, 1284 KiB  
Review
Recent Advances in Pharmaceuticals Biosorption on Microbial and Algal-Derived Biosorbents
by Zdravka Velkova, Kristiana Lazarova, Gergana Kirova and Velizar Gochev
Processes 2025, 13(2), 561; https://doi.org/10.3390/pr13020561 - 17 Feb 2025
Viewed by 508
Abstract
The removal of pharmaceuticals from aqueous environments has become a critical ecological challenge. Biosorption has emerged as a promising and cost-effective solution for pharmaceutical removal. This review examines the potential of microbial and algal-derived biosorbents, including fungi, bacteria, and algae, in the biosorption [...] Read more.
The removal of pharmaceuticals from aqueous environments has become a critical ecological challenge. Biosorption has emerged as a promising and cost-effective solution for pharmaceutical removal. This review examines the potential of microbial and algal-derived biosorbents, including fungi, bacteria, and algae, in the biosorption of pharmaceuticals from water. The removal efficiency of various types of biosorbents is discussed in relation to the chemical structure and functional groups presented on the biosorbent surfaces at various process parameters, such as pH, contact time, biosorbent dosage, and initial pharmaceutical concentration. Additionally, the benefits of chemical and physical modifications, immobilization techniques, and the reusability of biosorbents are highlighted. The major goal of the present review is not just to gather and discuss information about possible mechanisms of biosorption, which to some extent are still speculative, and to explain the effect of process parameters on the removal but also to highlight the advantages and disadvantages of various types of microbial/algal biosorbents and to ease the selection of proper biosorbents for pharmaceuticals removal. In this way, the review will benefit and induce more technological studies in the field of biosorption. Full article
(This article belongs to the Special Issue Feature Review Papers in Section “Pharmaceutical Processes”)
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25 pages, 5846 KiB  
Article
Harvesting Salinity Gradient Energy by Diffusion of Ions, Liquid Water, and Water Vapor
by Joost Veerman
Processes 2025, 13(2), 554; https://doi.org/10.3390/pr13020554 - 16 Feb 2025
Viewed by 443
Abstract
In this paper, we briefly discuss the main points of salinity gradient energy (SGE). First, we discuss the sources of SGE and the methods to harvest it. Then, we calculate, using the laws of physical chemistry, the amount of energy that can be [...] Read more.
In this paper, we briefly discuss the main points of salinity gradient energy (SGE). First, we discuss the sources of SGE and the methods to harvest it. Then, we calculate, using the laws of physical chemistry, the amount of energy that can be harvested with three selected methods based on the diffusion of ions, liquid water, and water vapor, respectively. Then, we give an overview of the applications, highlighting a number of new developments such as assisted reverse electrodialysis (ARED) and energy storage. It turns out that reverse electrodialysis offers unexpected possibilities such as energy storage, utilizing waste heat, and the administration of transdermal drug delivery, a technique that has been launched very recently. Full article
(This article belongs to the Special Issue Heat and Mass Transfer Phenomena in Energy Systems)
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30 pages, 2270 KiB  
Article
Implementation of a Sustainable Framework for Process Optimization Through the Integration of Robotic Process Automation and Big Data in the Evolution of Industry 4.0
by Leonel Patrício, Leonilde Varela and Zilda Silveira
Processes 2025, 13(2), 536; https://doi.org/10.3390/pr13020536 - 14 Feb 2025
Viewed by 720
Abstract
This study explores the integration of Robotic Process Automation (RPA) and Big Data within a sustainable framework for process optimization in the context of Industry 4.0. As industries strive to enhance operational efficiency while maintaining sustainability, the need for innovative solutions has become [...] Read more.
This study explores the integration of Robotic Process Automation (RPA) and Big Data within a sustainable framework for process optimization in the context of Industry 4.0. As industries strive to enhance operational efficiency while maintaining sustainability, the need for innovative solutions has become crucial. The research applies the PICO methodology (Population, Intervention, Comparison, Outcome) to assess the impact of combining these technologies on process optimization and sustainability. Through a real-world case study, the study demonstrates that the integration of RPA and Big Data significantly reduces execution times, minimizes operational errors, and promotes sustainable business practices. The results show that the combined framework not only enhances efficiency but also contributes to lower economic, environmental, and social impacts. The findings validate the research hypotheses, proving that the proposed framework fosters a balance between technological advancement and sustainability. This study provides valuable insights into the potential of Industry 4.0 technologies to drive both operational efficiency and corporate responsibility, offering a novel approach for industries seeking to embrace digital transformation while achieving long-term sustainability. The research contributes to the growing body of knowledge on the synergy between RPA, Big Data, and sustainability in industrial contexts. Full article
(This article belongs to the Special Issue Process Systems Engineering-Incubating Sustainability for Industrial Revolution 4.0)
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15 pages, 1656 KiB  
Article
Pre-Treatment Impact on Freeze-Drying Process and Properties of Dried Blueberries
by Ewa Jakubczyk, Ewelina Tryzno-Gendek, Anna Kot, Anna Kamińska-Dwórznicka and Dorota Nowak
Processes 2025, 13(2), 537; https://doi.org/10.3390/pr13020537 - 14 Feb 2025
Viewed by 540
Abstract
This study has aimed to determine the effect of pre-treatment with enzymes, ultrasound, and fruit skin perforation on the kinetics of the freeze-drying process and selected properties of the dried blueberries. The dry matter, water activity, maximal compression force, and content of flavonoids, [...] Read more.
This study has aimed to determine the effect of pre-treatment with enzymes, ultrasound, and fruit skin perforation on the kinetics of the freeze-drying process and selected properties of the dried blueberries. The dry matter, water activity, maximal compression force, and content of flavonoids, polyphenols, and anthocyanins after the pre-treatment and drying process were measured. The enzymatic, ultrasonic, and puncture treatments reduced the hardness of the blueberries by 2.5-fold, while the content of most bioactive compounds remained similar. The structure analysis has shown that freeze-dried blueberries without pre-treatment, but subjected to sonication, were almost hollow inside due to tissue rupture. It resulted in a decrease in the hardness of dried blueberries from 324.2 N (punctured) to 107.5 N (fresh) and 184.5 N (sonicated). The content of polyphenols ranged from 173.2 to 251.0 mg GAE/g d.m. in the fruits subjected to the enzymatic treatment and perforation, respectively. The application of pre-treatment with enzymes and puncturing may be recommended for the freeze-drying of blueberries as it reduces drying time by half. Moreover, the obtained products had a similar content of most bioactive compounds to those observed for freeze-dried blueberries without pre-treatment. Full article
(This article belongs to the Special Issue Quality of Plant Raw Materials and Their Processing)
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17 pages, 12255 KiB  
Article
Thermochromically Enhanced Lubricant System for Temperature Measurement in Cold Forming
by Christoph Kuhn, Patrick Volke and Peter Groche
Processes 2025, 13(2), 513; https://doi.org/10.3390/pr13020513 - 12 Feb 2025
Viewed by 479
Abstract
Cold forming offers high dimensional accuracy, energy and cost efficiency in the mass production of highly stressed components but is also associated with high tribological loads. Complex lubrication systems are required to ensure smooth production. As environmental standards rise, traditional zinc phosphate-based lubricants [...] Read more.
Cold forming offers high dimensional accuracy, energy and cost efficiency in the mass production of highly stressed components but is also associated with high tribological loads. Complex lubrication systems are required to ensure smooth production. As environmental standards rise, traditional zinc phosphate-based lubricants are to be replaced by less harmful single-layer systems. However, these new lubricants are temperature-sensitive, which requires precise knowledge of the temperatures in the forming zone for optimal design. Due to high compressive stress, conventional measuring methods cannot measure temperatures directly in the forming zone. In this work, lubricants are expanded into a temperature sensor using thermochromic pigments so that temperatures can be measured directly in the forming zone. This work outlines the selection and integration of the indicators, the development of a calibration method for thermochromic lubricants to characterize the correlation between colour value and temperature. It is shown that the lubricant behaviour does not deteriorate up to concentrations of 10%. The transfer of the measurement methodology from the laboratory application to the industrial multi-stage process has been successfully implemented and local temperature peaks are measured directly in the contact zone and correspond to the simulation results. The results of the work show an approach to closing the gap identified in existing research work, namely that the temperature cannot be measured directly in the forming zone during cold forging. The measuring system developed can be transferred to various processes in the future and contribute to the identification of correlations between temperature, lubricant failure and wear. Full article
(This article belongs to the Special Issue Recent Advances in Surface Engineering and Coating Technologies in Manufacturing Processes)
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53 pages, 5282 KiB  
Review
A Comparative Review of IG-541 System Use in Total Flooding Application for Energized Electrical Fire
by Kheng Hooi Loo, Tin Sin Lee and Soo Tueen Bee
Processes 2025, 13(2), 485; https://doi.org/10.3390/pr13020485 - 10 Feb 2025
Viewed by 1361
Abstract
Clean agent fire suppression systems are commonly used to protect areas containing valuable or critical equipment, especially in data centers and electrical substations, where traditional fire suppression methods are less effective or pose additional risks. This review evaluates the IG-541 fire suppression system [...] Read more.
Clean agent fire suppression systems are commonly used to protect areas containing valuable or critical equipment, especially in data centers and electrical substations, where traditional fire suppression methods are less effective or pose additional risks. This review evaluates the IG-541 fire suppression system as an alternative to halocarbon-based agents like HFC-227ea and FK-5-1-12, which are being phased out under environmental regulations, focusing on their application in energized electrical fires. IG-541 offers environmental advantages, including zero ozone depletion potential, no global warming potential, and negligible atmospheric lifetime, making it compliant with stringent environmental regulations. This review compares IG-541 with halocarbon agents across parameters such as extinguishing efficacy, safety considerations, environmental impacts, cost impacts, and system design considerations. Key findings underscore IG-541’s effectiveness in reducing fire damage without producing harmful by-products or exacerbating climate change. Furthermore, the study highlights the regulatory frameworks influencing the phase-out of halocarbon agents and the transition toward environmentally sustainable alternatives. While IG-541 emerges as a promising replacement for halocarbon agents, further exploration into its application in varied fire scenarios and energy-intensive environments is recommended to optimize its deployment. Full article
(This article belongs to the Special Issue Process Systems Engineering-Incubating Sustainability for Industrial Revolution 4.0)
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18 pages, 2592 KiB  
Article
Use of Wastewaters from Ethanol Distilleries and Raw Glycerol for Microbial Oil Production
by Evelyn Faife, Nayra Ochoa, Jingyang Xu, Dehua Liu, Wei Du, Manuel Díaz and María Guadalupe Aguilar-Uscanga
Processes 2025, 13(2), 467; https://doi.org/10.3390/pr13020467 - 8 Feb 2025
Cited by 1 | Viewed by 543
Abstract
The production of biodiesel from single-cell oils (SCOs) utilizing industrial wastes as feedstock presents an economically viable approach. To date, studies have rarely reported the utilization of vinasse combined with industrial glycerol for the production of SCO. This study aimed to assess the [...] Read more.
The production of biodiesel from single-cell oils (SCOs) utilizing industrial wastes as feedstock presents an economically viable approach. To date, studies have rarely reported the utilization of vinasse combined with industrial glycerol for the production of SCO. This study aimed to assess the performance of a Rhodotorula toruloides strain in vinasse from ethanol distilleries supplemented with pure/raw glycerol as an affordable carbon feedstock for SCO production. Several critical factors, including the C/N ratio, the impact of impurities in the crude glycerol, the proper nitrogen source, and the effects of the vinasse compositions, were evaluated. The results showed that the incorporation of urea and raw glycerol increased the lipid content to 51.8 ± 1.6% and the lipid productivity to 0.034 ± 0.001 g L−1h−1. Elevated biomass (42.5 g L−1) and lipid (11.0 g L−1) concentrations indicated that impurities in the raw glycerol positively affected the growth and lipid accumulation of this strain. Notably, supplementing raw glycerol to the vinasse led to a 16.1% increase in biomass concentration and a 25.7% rise in lipid content, significantly enhancing lipid productivity by 59.6%. The fatty acid profile predominantly featured unsaturated fatty acids (96.8%), including high percentages of stearic acid (41.8 ± 2.6%), palmitic acid (21.8 ± 1.5%), and oleic acid (18.3 ± 1.4%), aligning with the standards for vegetable-oil-based biodiesel manufacture. Fed-batch strategies using pulse-feeding turned out to be less effective than the constant-flow feeding strategy with vinasse supplemented with raw glycerol, which achieved a higher lipid productivity of 0.30 g L−1h−1. Full article
(This article belongs to the Special Issue Overview, Challenges and Current Trends in H2 Energy, Gasification, Waste and Biomass)
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28 pages, 5156 KiB  
Article
Esterification of Kenaf Core Fiber as a Potential Adsorbent for Oil Removal from Palm Oil Mill Effluent (POME)
by Nor Halaliza Alias, Luqman Chuah Abdullah, Thomas Choong Shean Yaw, Siti Nurul Ain Md Jamil, Teo Ming Ting, Ahmad Jaril Asis, Chuan Li Lee and Abel Adekanmi Adeyi
Processes 2025, 13(2), 463; https://doi.org/10.3390/pr13020463 - 8 Feb 2025
Viewed by 486
Abstract
Palm oil mill effluent (POME) is a major contributor to industrial oily wastewater in Malaysia, demanding effective treatment solutions. This study explores the potential of esterified kenaf core (EKC) fiber as an oil adsorbent for oil removal from POME, optimized using a full [...] Read more.
Palm oil mill effluent (POME) is a major contributor to industrial oily wastewater in Malaysia, demanding effective treatment solutions. This study explores the potential of esterified kenaf core (EKC) fiber as an oil adsorbent for oil removal from POME, optimized using a full central composite design (CCD) within the response surface methodology (RSM) framework. The optimum conditions achieved 76% oil removal efficiency, with a 1:0.5 ratio of mercerized kenaf core to stearic acid (MKC:SA), 15 wt% of catalyst, and 1 h reflux time during the esterification process. The regression model exhibited strong predictive capability, with a significant quadratic correlation and an R2 value of 0.94. The Fourier transform infrared (FTIR) spectroscopy revealed the existence of ester functional groups characterized by significant hydrophobicity and a decrease in hydroxyl groups, indicating the chemical changes of EKC. Moreover, the scanning electron microscopy (SEM) research demonstrated structural alterations in EKC, including heightened surface roughness, fibrillation, and pore development, which improved oil adhesion relative to raw kenaf core (RKC). These findings indicate that EKC provides an effective, environmentally sustainable solution for managing oil wastewater issues in the palm oil sector, facilitating enhanced ecological sustainability and resource management. Full article
(This article belongs to the Special Issue Process Systems Engineering-Incubating Sustainability for Industrial Revolution 4.0)
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19 pages, 1113 KiB  
Article
Predicting and Understanding Emergency Shutdown Durations Level of Pipeline Incidents Using Machine Learning Models and Explainable AI
by Lemlem Asaye, Chau Le, Ying Huang, Trung Q. Le, Om Prakash Yadav and Tuyen Le
Processes 2025, 13(2), 445; https://doi.org/10.3390/pr13020445 - 7 Feb 2025
Viewed by 751
Abstract
Pipeline incidents pose significant concerns due to their potential environmental, economic, and safety risks, emphasizing the critical need to understand and manage this vital infrastructure. While existing studies predominantly focus on the causes of pipeline incidents and failures, few have investigated the consequences, [...] Read more.
Pipeline incidents pose significant concerns due to their potential environmental, economic, and safety risks, emphasizing the critical need to understand and manage this vital infrastructure. While existing studies predominantly focus on the causes of pipeline incidents and failures, few have investigated the consequences, such as shutdown duration, and most lack comprehensive models capable of accurately predicting and providing actionable insights into the risk factors. This study bridges this gap by employing machine learning (ML) techniques, including Random Forest and Light Gradient Boosting Machine (LightGBM), for classifying pipeline incidents’ emergency shutdown duration levels. These techniques are specifically designed to capture complex, nonlinear patterns and interdependencies within the data, addressing the limitations of traditional linear approaches. The proposed model has further enhanced with Explainable AI (XAI) techniques, such as Shapley Additive exPlanations (SHAP) values, to improve interpretability and provide insights into the factors influencing shutdown durations. Historical incident data, collected from the Pipeline and Hazardous Materials Safety Administration (PHMSA) from 2010 to 2022, were utilized to examine the risk factors. K-Fold Cross-Validation with 5 folds was employed to ensure the model’s robustness. The results demonstrate that the LightGBM model achieved the highest accuracy of 75.0%, closely followed by Random Forest at 74.8%. The integration of XAI techniques provides actionable insights into key factors such as pipeline material, age, installation layout, and commodity type, which significantly influence shutdown durations. These findings underscore the practical implications of the proposed approach, enabling pipeline operators, emergency responders, and regulatory authorities to make informed decisions that optimize resource allocation and mitigate risks effectively. Full article
(This article belongs to the Special Issue Application of Artificial Intelligence in Industrial Process Modelling and Optimization)
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16 pages, 2189 KiB  
Article
Enzymatic Synthesis of Bioactive Structured DHA Phospholipids via Stable Immobilized Phospholipase-Catalyzed Esterification in a Solvent-Free Medium
by Ernestina Garcia-Quinto, Jose M. Guisan and Gloria Fernandez-Lorente
Processes 2025, 13(2), 442; https://doi.org/10.3390/pr13020442 - 6 Feb 2025
Viewed by 787
Abstract
The enzymatic esterification of docosahexaenoic acid (DHA) with glycerophosphocholine (GPC) was investigated to produce bioactive structured DHA phospholipids with DHA esterified at the sn-2 position, which may contribute to the prevention of neurodegenerative diseases such as Alzheimer’s. This reaction is complex due to [...] Read more.
The enzymatic esterification of docosahexaenoic acid (DHA) with glycerophosphocholine (GPC) was investigated to produce bioactive structured DHA phospholipids with DHA esterified at the sn-2 position, which may contribute to the prevention of neurodegenerative diseases such as Alzheimer’s. This reaction is complex due to the low solubility of GPC in anhydrous organic media and the limited stability of enzymes under such conditions. The immobilized phospholipase Quara® LowP (QlowP-C18) proved to be the most effective catalyst, achieving a 58% yield of di-substituted DHA phospholipids (Di-DHA-PC) in just 48 h under optimal conditions (solvent-free media at 60 °C) with 95% purity. Advanced immobilization and post-immobilization techniques significantly improved the stability of QlowP-C18, increasing its longevity threefold and enabling reuse for up to five reaction cycles at 40 °C. The total production reached 120.4 mg of highly pure DHA-di-substituted phospholipid. These findings highlight the effectiveness of stable immobilized enzymes in solvent-free systems and underscore their potential for the efficient and sustainable production of highly pure Di-DHA-PC, which could be used as a functional or nutraceutical ingredient for the prevention of neurodegenerative diseases. Full article
(This article belongs to the Section Food Process Engineering)
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16 pages, 4394 KiB  
Article
Advanced Process Control Strategies for Efficient Methanol Production from Natural Gas
by Md Emdadul Haque and Srinivas Palanki
Processes 2025, 13(2), 424; https://doi.org/10.3390/pr13020424 - 5 Feb 2025
Viewed by 843
Abstract
Natural gas-to-methanol plants are receiving renewed interest with the significant increase in shale gas availability. Methanol serves as a crucial raw material for producing various industrial and consumer goods as well as key platform chemicals, including acetic acid, methyl tertiary butyl ether, dimethyl [...] Read more.
Natural gas-to-methanol plants are receiving renewed interest with the significant increase in shale gas availability. Methanol serves as a crucial raw material for producing various industrial and consumer goods as well as key platform chemicals, including acetic acid, methyl tertiary butyl ether, dimethyl ether, and methylamine. In this research, a dynamic model is developed for Natgasoline’s methanol manufacturing plant. A hierarchical control system comprising Dynamic Matrix Control (DMC) and a basic regulatory control loop is constructed using this dynamic model to minimize methanol losses and utility costs under various process upsets. A subspace identification methodology is used to develop rigorous DMCplus controller models. The simulation results in the ASPEN manufacturing software platform show that the DMCplus controller developed in this study can reduce methanol losses by 96% and utility requirements by 40%. The controller is robust to feed flow variations of ±10%. Furthermore, disturbances due to the variation in hydrogen content in the syngas are also successfully rejected by the controller. This hierarchical multivariable control system performs significantly better than the traditional regulatory PID control strategy in optimizing the methanol process under process constraints. Full article
(This article belongs to the Special Issue Industrial Chemistry Reactions (3rd Edition): Kinetics, Mass and Heat Transfer in View of the Industrial Reactors Design)
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32 pages, 4103 KiB  
Review
Strategic Selection of a Pre-Reduction Reactor for Increased Hydrogen Utilization in Hydrogen Plasma Smelting Reduction
by Bernhard Adami, Felix Hoffelner, Michael Andreas Zarl and Johannes Schenk
Processes 2025, 13(2), 420; https://doi.org/10.3390/pr13020420 - 5 Feb 2025
Viewed by 897
Abstract
The hydrogen plasma smelting reduction process has the potential to drastically reduce the CO2 emissions of the steel industry by using molecular, atomic and ionized hydrogen as a reducing agent for iron ores. To increase the hydrogen and thermal efficiency of the [...] Read more.
The hydrogen plasma smelting reduction process has the potential to drastically reduce the CO2 emissions of the steel industry by using molecular, atomic and ionized hydrogen as a reducing agent for iron ores. To increase the hydrogen and thermal efficiency of the process, a pre-reduction and pre-heating stage should be incorporated in a future upscaling of an existing HPSR demonstration plant within the scope of the “SuSteel follow-up” project to a target capacity of 200 kg/h of iron ore. The determination of the optimal process parameters is followed by a review of possible reactor types. A fluidized bed cascade, a cyclone cascade and a rotary kiln are compared for this purpose. Their applicability for the hydrogen plasma smelting is discussed, based on their fundamental design and operational procedures. Additionally, critical features of the different reactor types are outlined. A cyclone cascade with at least 3 stages is proposed to be the optimal reactor for pre-heating and pre-reducing the input material for the upscaled hydrogen plasma smelting reduction demonstration plant, based on the assessment. Full article
(This article belongs to the Special Issue Innovations in Manufacturing Processes and Systems for Sustainable Practices)
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14 pages, 2202 KiB  
Article
Fault Diagnosis of Wire Disconnection in Heater Control System Using One-Dimensional Convolutional Neural Network
by Jiawei Guo, Linfeng Sun, Takahiro Kawaguchi and Seiji Hashimoto
Processes 2025, 13(2), 402; https://doi.org/10.3390/pr13020402 - 3 Feb 2025
Viewed by 892
Abstract
Heaters are critical components in various heating control systems, and their faults are often a primary cause of system failure, drawing significant attention from engineers and researchers. Early and accurate fault diagnosis is crucial to prevent cascading failures. Many diagnostic methods target faults [...] Read more.
Heaters are critical components in various heating control systems, and their faults are often a primary cause of system failure, drawing significant attention from engineers and researchers. Early and accurate fault diagnosis is crucial to prevent cascading failures. Many diagnostic methods target faults under generally stable and simple operating conditions, such as constant load or steady-state temperature. However, real-world scenarios are often complex and variable, involving dynamic loads, nonlinear temperature rises, and other challenges, which limit diagnostic accuracy. To address this issue, this paper proposes an intelligent fault diagnosis model based on a one-dimensional convolutional neural network (CNN), using the heater’s current and voltage as the input to the neural network. The effectiveness and accuracy of the proposed model were validated through experimental data under two different conditions, achieving an average accuracy rate of 98%. The disconnection faults were generated during actual operation and occurred in the early stages, differing significantly from artificially simulated faults, thereby increasing the difficulty of accurate diagnosis. Analysis and comparison of the experimental results demonstrate the feasibility of the intelligent diagnostic model and its high diagnostic accuracy. Full article
(This article belongs to the Special Issue Research on Intelligent Fault Diagnosis Based on Neural Network)
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13 pages, 3952 KiB  
Article
CTAB-Assisted Formation of Hierarchical Porosity in Cu-BDC-NH2 Metal–Organic Frameworks and Its Enhanced Peroxidase-like Catalysis for Xanthine Sensing
by Chao Tan, Junjie He, Fei Zhou, Ruicheng Xu, Yilei Gao, Robert S. Marks and Junji Li
Processes 2025, 13(2), 387; https://doi.org/10.3390/pr13020387 - 31 Jan 2025
Viewed by 871
Abstract
A novel porous metal-organic framework (MOF), pCu-BDC-NH2, with hierarchical porosity was synthesized using cetyltrimethylammonium bromide (CTAB) as a pore-generation agent. In addition to its common functions including structure-directing ligands or soft micelle templates, the judicious use of CTAB effectively modulated pore [...] Read more.
A novel porous metal-organic framework (MOF), pCu-BDC-NH2, with hierarchical porosity was synthesized using cetyltrimethylammonium bromide (CTAB) as a pore-generation agent. In addition to its common functions including structure-directing ligands or soft micelle templates, the judicious use of CTAB effectively modulated pore architecture in Cu-BDC-NH2 MOFs. With additional mesopores generated during the synthesis process, the intrinsic MOF scaffolds further obtained pore hierarchies and interconnectivity, enabling efficient substrate access to the active metal centers, and thus significantly facilitated catalytic performance. As a proof of concept, we applied the finely engineered porous MOF pCu-BDC-NH2 in a cascaded enzymatic system for xanthine sensing. This colorimetric biosensor exhibited a low detection limit of 0.11 μM, and a wide linear range of 1–120 μM. Furthermore, the sensor demonstrated exceptional stability, reproducibility, and was independent of interferences. Our simple yet effective method may find broader applications in tailoring pore architecture, enabling finer engineered structures to improve catalytic activities of nanomaterials. Full article
(This article belongs to the Special Issue Metal–Organic Frameworks for Separation, Catalysis and Energy Applications)
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26 pages, 949 KiB  
Review
Biosensors for Detecting Food Contaminants—An Overview
by António Inês and Fernanda Cosme
Processes 2025, 13(2), 380; https://doi.org/10.3390/pr13020380 - 30 Jan 2025
Cited by 1 | Viewed by 1556
Abstract
Food safety is a pressing global concern due to the risks posed by contaminants such as pesticide residues, heavy metals, allergens, mycotoxins, and pathogenic microorganisms. While accurate, traditional detection methods like ELISA, HPLC, and mass spectrometry are often time-consuming and resource-intensive, highlighting the [...] Read more.
Food safety is a pressing global concern due to the risks posed by contaminants such as pesticide residues, heavy metals, allergens, mycotoxins, and pathogenic microorganisms. While accurate, traditional detection methods like ELISA, HPLC, and mass spectrometry are often time-consuming and resource-intensive, highlighting the need for innovative alternatives. Biosensors based on biological recognition elements such as enzymes, antibodies, and aptamers, offer fast, sensitive, and cost-effective solutions. Using transduction mechanisms like electrochemical, optical, piezoelectric, and thermal systems, biosensors provide versatile tools for detecting contaminants. Advances in DNAzyme- and aptamer-based technologies enable the precise detection of heavy metals, while enzyme- and protein-based biosensors monitor metal-induced changes in biological activity. Innovations like microbial biosensors and DNA-modified electrodes enhance detection accuracy. Biosensors are also highly effective in identifying pesticide residues, allergens, mycotoxins, and pathogens through immunological, enzymatic, and nucleic acid-based techniques. The integration of nanomaterials and bioelectronics has significantly improved the sensitivity and performance of biosensors. By facilitating real-time, on-site monitoring, these devices address the limitations of conventional methods to ensure food quality and regulatory compliance. This review highlights the transformative role of biosensors and how biosensors are improved by emerging technologies in food contamination detection, emphasizing their potential to mitigate public health risks and enhance food safety throughout the supply chain. Full article
(This article belongs to the Special Issue Application of Artificial Intelligence in Industrial Process Modelling and Optimization)
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14 pages, 3553 KiB  
Article
Simulation Study of the Effects of Foam Rheology on Hydraulic Fracture Proppant Placement
by Tuan Tran, Giang Hoang Nguyen, Maria Elena Gonzalez Perdomo, Manouchehr Haghighi and Khalid Amrouch
Processes 2025, 13(2), 378; https://doi.org/10.3390/pr13020378 - 30 Jan 2025
Viewed by 648
Abstract
Hydraulic fracture stimulation is one of the most effective methods to recover oil and gas from unconventional resources. In recent years, foam-based fracturing fluids have been increasingly studied to address the limitations of conventional slickwater such as high water and chemical consumption, environmental [...] Read more.
Hydraulic fracture stimulation is one of the most effective methods to recover oil and gas from unconventional resources. In recent years, foam-based fracturing fluids have been increasingly studied to address the limitations of conventional slickwater such as high water and chemical consumption, environmental concerns, and high incompatibility with water-sensitive formations. Due to the gradual breakdown of liquid foams at reservoir conditions, the combination of silica nanoparticles (SNP) and surfactants has attracted a lot of attention to improve liquid foams’ characteristics, including their stability, rheology, and proppant-carrying capacity. This paper investigates and compares the effects of cationic and anionic surfactants on the fracturing performance of SNP-stabilized foams at the reservoir temperature of 90 °C. The experimental results of viscosity measurements were imported into a 3D fracture-propagation model to evaluate the effectiveness of fracturing foams in transporting and distributing proppants in the fracture system. At both ambient and elevated temperatures, cationic surfactant was experimentally found to have better synergistic effects with SNP than anionic surfactant in improving the apparent viscosity and proppant-carrying capacity of foams. The simulation results demonstrate that fracturing with cationic surfactant-SNP foam delivers greater performance with larger propped area by 4%, higher fracture conductivity by 9%, and higher cumulative gas production by 13%, compared to the anionic surfactant-SNP foam. This research work not only helps validate the interrelationship between fluid viscosity, proppant settlement rate, and fracture effectiveness, but it also emphasizes the importance of proppant placement in enhancing fracture conductivity and well productivity. Full article
(This article belongs to the Special Issue Natural Gas Hydrate Production Technology and Rock Mechanics in Petroleum Engineering (Volume II))
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23 pages, 3222 KiB  
Article
Optimizing the Enzymatic Hydrolysis of Bioflocculated Microalgae for Bioethanol Production
by Viviane Simon, João Felipe Freitag, Júlia Lorenzato da Silva and Luciane Maria Colla
Processes 2025, 13(2), 364; https://doi.org/10.3390/pr13020364 - 28 Jan 2025
Viewed by 891
Abstract
Spirulina platensis is a promising microalga, but biomass harvesting remains a challenge. Fungal bioflocculation offers a potential solution, facilitating the production of valuable bioproducts like bioethanol. Effective cell disruption methods, including physical-chemical and enzymatic treatments, can enhance biomass utilization. However, commercial enzymes are [...] Read more.
Spirulina platensis is a promising microalga, but biomass harvesting remains a challenge. Fungal bioflocculation offers a potential solution, facilitating the production of valuable bioproducts like bioethanol. Effective cell disruption methods, including physical-chemical and enzymatic treatments, can enhance biomass utilization. However, commercial enzymes are not optimized for microalgae, necessitating research on ideal operational conditions. This study evaluated physical and enzymatic processes to hydrolyze bioflocculated microalgae for bioethanol production. The microalga was harvested using a fungal bioflocculant produced via submerged fermentation. Biomass hydrolysis involved physical methods (autoclaving, ultrasound + autoclaving, ultrasound + gelatinization, and gelatinization) combined with enzymes (amylase, amyloglucosidase, cellulase, and xylanase), optimized for pH, temperature, and enzyme load. Hydrolysates were then used for bioethanol production. Results showed a microalgae harvest efficiency of 99.7% with a 1:8 fungus-to-microalgae ratio. Enzyme optimization identified ideal conditions (e.g., pH 4.5; 60 °C for amylase/amyloglucosidase, 70 °C for cellulase, and 50 °C for xylanase). Combined enzymatic treatments achieved approximately 70% hydrolysis efficiency, yielding 19.06 g/L glucose and 7.29 g/L ethanol (~79% conversion). Ethanol productivity was ~0.6 g per 1 g bioflocculated biomass L−1·hr. These findings highlight the potential of enzymatic hydrolysis for complex biomasses, although further studies are needed to refine enzyme applications for better biomass utilization. Full article
(This article belongs to the Special Issue Green Conversion Processes of Waste and Biomass Materials)
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23 pages, 3918 KiB  
Article
Bioassays to Assess the Safety of Potassium and Sodium Nitrates and Nitrites
by Tania Merinas-Amo, Rocío Merinas-Amo, Laura Márquez Prados, Rafael Font, Mercedes Del Río Celestino and Ángeles Alonso-Moraga
Processes 2025, 13(2), 325; https://doi.org/10.3390/pr13020325 - 24 Jan 2025
Viewed by 745
Abstract
(1) Background: Advances in food processing practices and health care are some of the most significant advances in modern daily life. The goal of this study is to evaluate the safety of potassium and sodium nitrates and nitrites when they are used as [...] Read more.
(1) Background: Advances in food processing practices and health care are some of the most significant advances in modern daily life. The goal of this study is to evaluate the safety of potassium and sodium nitrates and nitrites when they are used as fertilizers in agriculture and food additives, as well as the known conversion of nitrate to nitrite in humans. (2) Methods: Various bioassays were conducted to investigate the effects of nitrates and nitrites in the Drosophila melanogaster genetic tester system. These assays focused on the modulation of degenerative processes at the molecular, cellular, individual, and population levels. Additionally, we assessed the chemopreventive potential and the ability to induce DNA strand breaks in HL-60 tumour cells. (3) Results: All nitrate and nitrite concentrations tested were shown to not be toxic or genotoxic in Drosophila since none of the compounds reached the LD50 and significant genetic mutation. A positive or null protective capacity against a toxic agent was found for nitrates, not for nitrites, showing that sodium nitrite has a synergistic effect when combined with the oxidant toxin hydrogen peroxide; and a nutraceutical potential in the lifespan only for sodium nitrate to improve the quality of life in 5 days at ADI concentration. The in vitro results in human leukemia cells showed a chemopreventive potential only for potassium nitrate and sodium nitrite due to reducing the viability of HL-60 cells growth to 18% and 29%, respectively, compared to the controls at ADI (acceptable daily intake) concentrations. However, neither of these showed DNA damage or methylation modifications. (4) Conclusions: The tested compounds were shown to be safe to use during in vivo and in vitro tests when used at the extrapolated ADI concentrations. Full article
(This article belongs to the Special Issue Processing Foods: Process Optimization and Quality Assessment, 3rd Edition)
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21 pages, 5189 KiB  
Article
Simulation Tool for the Techno-Economic Assessment of the Integrated Production of Polyhydroxyalkanoates as Value-Added Byproducts of a Wastewater Treatment Plant
by Laura Pozo-Morales, Antonio Rosales Martínez, Enrique Baquerizo and Germán del Valle Agulla
Processes 2025, 13(2), 295; https://doi.org/10.3390/pr13020295 - 21 Jan 2025
Cited by 1 | Viewed by 1457
Abstract
The polyhydroxyalkanoate (PHA) production process that uses mixed microbial cultures combined with main stream wastewater treatment plants (WWTPs) is a competitive integrated resource recovery process in which non-oxygen electron acceptors can be used to enrich the PHA producer. Trials carried out in operating [...] Read more.
The polyhydroxyalkanoate (PHA) production process that uses mixed microbial cultures combined with main stream wastewater treatment plants (WWTPs) is a competitive integrated resource recovery process in which non-oxygen electron acceptors can be used to enrich the PHA producer. Trials carried out in operating plants are very scarce, and there are no simulation tools available to analyse the feasibility of integrating the two processes. This research presents a novel analysis tool for a techno-economic assessment of value-added biopolymers. A general model for a conventional WWTP has been designed and eventually validated using the operating data collected in the database of a fully operational plant. In the model, a simulation of a PHA production line based on thickened primary sludge as a substrate has been integrated. The assembly has been treated as a closed-loop system with an accuracy level of 0.1% with a limit of 1000 iterations. Two strategies based on internal (ADF) or external (AN/AD) limitations of some nutrients have been contrasted for the selection of a biomass capable of feast–famine PHA synthesis. The ADF strategy was found to be the most favourable system, with a production of 0.226 kg of CODPHA·kg−1 COD. The calculated production cost was EUR 0.11·kg−1 CODPHA. The sludge production was reduced by 6%. Full article
(This article belongs to the Special Issue Wastewater and Waste Treatment: Overview, Challenges and Current Trends (Volume II))
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38 pages, 3394 KiB  
Review
A Compact Review of Current Technologies for Carbon Capture as Well as Storing and Utilizing the Captured CO2
by Tim M. Thiedemann and Michael Wark
Processes 2025, 13(1), 283; https://doi.org/10.3390/pr13010283 - 20 Jan 2025
Cited by 3 | Viewed by 3915
Abstract
With the consequences of climate change becoming more urgent, there has never been a more pressing need for technologies that can help to reduce the carbon dioxide (CO2) emissions of the most polluting sectors, such as power generation, steel, cement, and [...] Read more.
With the consequences of climate change becoming more urgent, there has never been a more pressing need for technologies that can help to reduce the carbon dioxide (CO2) emissions of the most polluting sectors, such as power generation, steel, cement, and the chemical industry. This review summarizes the state-of-the-art technologies for carbon capture, for instance, post-combustion, pre-combustion, oxy-fuel combustion, chemical looping, and direct air capture. Moreover, already established carbon capture technologies, such as absorption, adsorption, and membrane-based separation, and emerging technologies like calcium looping or cryogenic separation are presented. Beyond carbon capture technologies, this review also discusses how captured CO2 can be securely stored (CCS) physically in deep saline aquifers or depleted gas and oil reservoirs, stored chemically via mineralization, or used in enhanced oil recovery. The concept of utilizing the captured CO2 (CCU) for producing value-added products, including formic acid, methanol, urea, or methane, towards a circular carbon economy will also be shortly discussed. Real-life applications, e.g., already pilot-scale continuous methane (CH4) production from flue gas CO2, are shown. Actual deployment of the most crucial technologies for the future will be explored in real-life applications. This review aims to provide a compact view of the most crucial technologies that should be considered when choosing to capture, store, or convert CO2, informing future researchers with efforts aimed at mitigating CO2 emissions and tackling the climate crisis. Full article
(This article belongs to the Special Issue CO2 Capture and Conversion Processes: Recent Trends and Future Perspectives)
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19 pages, 7637 KiB  
Article
Design of Ejectors for High-Temperature Heat Pumps Using Numerical Simulations
by Julian Unterluggauer, Adam Buruzs, Manuel Schieder, Verena Sulzgruber, Michael Lauermann and Christoph Reichl
Processes 2025, 13(1), 285; https://doi.org/10.3390/pr13010285 - 20 Jan 2025
Viewed by 870
Abstract
Decarbonization of industrial processes by using high-temperature heat pumps is one of the most important pillars towards sustainable energy goals. Most heat pumps are based on the standard Carnot cycle which includes an expansion valve leading to irreversible dissipation and energetic losses. Especially [...] Read more.
Decarbonization of industrial processes by using high-temperature heat pumps is one of the most important pillars towards sustainable energy goals. Most heat pumps are based on the standard Carnot cycle which includes an expansion valve leading to irreversible dissipation and energetic losses. Especially for high-temperature applications, these losses increase significantly, and a replacement of the conventional throttle valve with an ejector, which is an alternative expansion device, for partial recovery of some of the pressure lost during the expansion, is investigated in this paper. However, designing such a device is complicated as the flow inside is subject to multiphase and supersonic conditions. Therefore, this paper aims to streamline an approach for designing ejectors for high-temperature heat pumps using numerical simulations. To showcase the application of the design procedure, an ejector, which is used to upgrade a standard cycle high-temperature heat pump with the synthetic refrigerant R1233zdE, is developed. To design the ejector heat pump, an interaction between a fast 1D design tool, a 1D heat pump cycle simulation, and a 2D CFD simulation is proposed. An ejector is designed for a sink temperature of 130 °C, which can potentially increase the COP of the heat pump by around 20%. Preliminary measurements at off-design conditions at 100 °C sink temperature are used to validate the design procedure. The pressure distribution inside the ejector is well captured, with relative errors around 4%. However, the motive nozzle mass flow was underpredicted by around 30%. To summarize, the presented approach can be used for designing ejectors of high-temperature heat pumps, although the numerical modeling has to be further developed by validation with experiments to improve the prediction of the motive mass flow. Full article
(This article belongs to the Special Issue Heat and Mass Transfer Phenomena in Energy Systems)
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14 pages, 2065 KiB  
Article
Generation of Hydrogen Peroxide in Beer and Selected Strong Alcoholic Beverages
by Małgorzata Rak, Dawid Mendys, Aleksandra Płatek, Oskar Sitarz, Ireneusz Stefaniuk, Grzegorz Bartosz and Izabela Sadowska-Bartosz
Processes 2025, 13(1), 277; https://doi.org/10.3390/pr13010277 - 20 Jan 2025
Cited by 1 | Viewed by 2183
Abstract
The generation of hydrogen peroxide has been documented in various plant-based beverages, such as coffee, tea, herbal infusions and wine, as well in energy drinks containing ascorbate and in plant-based food. There are no data in the literature on the presence and generation [...] Read more.
The generation of hydrogen peroxide has been documented in various plant-based beverages, such as coffee, tea, herbal infusions and wine, as well in energy drinks containing ascorbate and in plant-based food. There are no data in the literature on the presence and generation of hydrogen peroxide in beer and strong alcoholic beverages containing plant material. This study aimed to examine whether beer and selected strong alcoholic beverages (brandy, whisky and fruit liqueurs) contain hydrogen peroxide. The presence of hydrogen peroxide was found in freshly opened brandy, whisky, liqueurs and most diluted beers; subsequent incubation in an air atmosphere led to the generation of hydrogen peroxide. The presence of the electron paramagnetic resonance (EPR) signal of the semiquinone radical and the generation of the superoxide radical demonstrated in selected alcoholic beverages by the superoxide dismutase-inhibitable reduction of Nitrotetrazolium Blue and oxidation of dihydroethidium are in agreement with the two-step mechanism of generation of hydrogen peroxide by the autoxidation of phenolics. These results broaden the list of beverages containing and producing hydrogen peroxide. Full article
(This article belongs to the Special Issue Phenolic Profiling and Antioxidant Capacity in Agrifood Products (Volume II))
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25 pages, 11726 KiB  
Article
Low-Carbon Transformation of Polysilicon Park Energy Systems: Optimal Economic Strategy with TD3 Reinforcement Learning
by Shurui Hu, Chengwenxuan Zhao, Jialu Wu, Haiyang Bian, Yongkai Liu and Mingtao Li
Processes 2025, 13(1), 268; https://doi.org/10.3390/pr13010268 - 18 Jan 2025
Viewed by 935
Abstract
To achieve the low-carbon transition in polysilicon production, this study proposes and validates a low-carbon economic dispatch strategy for a renewable hydrogen production and storage system in polysilicon parks based by TD3 algorithm. The study uses XGBoost to construct a surrogate model that [...] Read more.
To achieve the low-carbon transition in polysilicon production, this study proposes and validates a low-carbon economic dispatch strategy for a renewable hydrogen production and storage system in polysilicon parks based by TD3 algorithm. The study uses XGBoost to construct a surrogate model that reflects the nonlinear physical characteristics of the electrolyzer. Through a comparative analysis of operating strategies in five scenarios and sensitivity assessments of key parameters, complemented by comparisons with dispatch results from the DDPG and DQN algorithms, the effectiveness of the coupled operating strategy for electrolyzers, energy storage, and hydrogen storage devices is fully validated. This highlights the critical role of the TD3 algorithm in strengthening the robustness of the energy system under double-end source-load uncertainties. The results show that batteries flexibly adjust to the time-of-use electricity price, and the coordinated operation of the hydrogen storage devices as well as electrolyzers stabilize the electrolyzer efficiency, reducing the total system cost by 0.027% compared to fixed condition equipment models. The TD3 algorithm shows significant advantages in optimized dispatch, reducing the average daily operating cost by 0.6% and 1.2%, respectively, compared to the DDPG and DQN algorithms, and reducing the carbon emission cost by 2.0% and 12.0%, respectively. A comprehensive analysis shows that the proposed model reduces daily carbon emissions by 29.3% compared to the original system, but also introduces cost pressure, mainly due to the high operating costs of renewable energy equipment such as solar panels. This study provides a practical solution for renewable energy management. Full article
(This article belongs to the Special Issue Renewable Energy Grid Integration and Carbon Reduction Strategies in Modern Power Markets)
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17 pages, 2458 KiB  
Article
Hydrolytic Decomposition of Corncobs to Sugars and Derivatives Using Subcritical Water
by Maja Čolnik, Mihael Irgolič, Amra Perva and Mojca Škerget
Processes 2025, 13(1), 267; https://doi.org/10.3390/pr13010267 - 18 Jan 2025
Viewed by 870
Abstract
Corncobs are a widespread and renewable by-product of corn cultivation that are typically considered waste or low-value material. Corncobs contain hemicellulose, cellulose, and lignin, which can be converted into valuable products using suitable techniques. Subcritical water is increasingly used as a green medium [...] Read more.
Corncobs are a widespread and renewable by-product of corn cultivation that are typically considered waste or low-value material. Corncobs contain hemicellulose, cellulose, and lignin, which can be converted into valuable products using suitable techniques. Subcritical water is increasingly used as a green medium for the extraction of valuable components from biomass, as it has many advantageous properties (high yield, pure extracts, shorter times) compared to other organic solvents. For this reason, subcritical water was used in this study to extract valuable components from corncobs at different temperatures (150–250 °C) and reaction times (10–60 min). During the decomposition of corncobs, numerous valuable products are formed in the aqueous phase depending on the temperature and reaction time. In addition to sugars and their derivatives, phenolic compounds were also formed, which are of great importance in numerous applications. It was found that at low temperatures (150–170 °C) the hemicellulose in the corncobs begins to decompose and, in particular, the sugars (glucose, xylose, arabinose, and galactose) are initially formed in the aqueous phase. Higher temperatures (200 and 250 °C) are more favorable for the decomposition of corncobs into valuable components. The yield of sugars increases with temperature due to the degradation of the cellulose content of the lignocellulosic biomass. At the same time, several new valuable products (furfural, 5-hydroxymethylfurfural (5-HMF), 1,3-dihydroxyacetone, levulinic acid, and formic acid as well as phenolic components) are formed through the degradation of lignin and the further degradation of sugars. The most important products are certainly the furfurals, which are central platform compounds. The highest furfural content was reached at 200 °C and 60 min and accounted for almost half of all components in the aqueous phase (472.01 ± 5.64 mg/g dry extract). These biomass-derived sugars and derivatives can be used in the production of fuels, pharmaceuticals, biodegradable polymers, and surfactants. Full article
(This article belongs to the Section Sustainable Processes)
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15 pages, 15119 KiB  
Article
Construction of Honeycomb-like ZnO/g-C3N5 Heterojunction for MB Photocatalytic Degradation
by Sitong Liu, Shicheng Liu, Letao Li, Letong Yang, Xiaodong Wu, Zhichun Si, Rui Ran and Hui Wu
Processes 2025, 13(1), 253; https://doi.org/10.3390/pr13010253 - 16 Jan 2025
Viewed by 725
Abstract
In this study, a combination of calcination and hydrothermal methods was employed to synthesize a honeycomb-like ZnO/g-C3N5 (ZCN) heterojunction in situ. The ZCN heterojunction photocatalyst exhibits remarkable photocatalytic degradation performance, achieving a 97% methyl blue (MB) degradation rate with the [...] Read more.
In this study, a combination of calcination and hydrothermal methods was employed to synthesize a honeycomb-like ZnO/g-C3N5 (ZCN) heterojunction in situ. The ZCN heterojunction photocatalyst exhibits remarkable photocatalytic degradation performance, achieving a 97% methyl blue (MB) degradation rate with the rate constant of 0.0433 min−1 (almost twice that of ZnO). Optical performance tests reveal that the ZCN heterojunction broadens the absorption edge to 710 nm and enhances the charge carrier separation. The presence of abundant oxygen vacancies, as revealed by X-ray photoelectron spectroscopy analysis, effectively suppresses the recombination of photogenerated electron–hole pairs. Furthermore, density functional theory simulations indicate that the combination of ZnO and g-C3N5 creates an internal electric field due to their differing work functions. This leads to the formation of a Z-scheme heterojunction that effectively suppresses charge carrier recombination and preserves the strong redox capabilities of ZnO and g-C3N5. Finally, electron spin resonance results indicate that O2− and OH are the primary active radicals involved in the degradation process. This study introduces a potential approach for the development of highly efficient Z-scheme photocatalysts for water treatment applications. Full article
(This article belongs to the Special Issue Continuous Production and Catalysis Optimization of Chemical Industry Processes)
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25 pages, 1585 KiB  
Article
Fuzzy Control of Multivariable Nonlinear Systems Using T–S Fuzzy Model and Principal Component Analysis Technique
by Basil Mohammed Al-Hadithi and Javier Gómez
Processes 2025, 13(1), 217; https://doi.org/10.3390/pr13010217 - 14 Jan 2025
Cited by 2 | Viewed by 751
Abstract
In this work, a new nonlinear control method is proposed, which integrates the Takagi–Sugeno (T–S) fuzzy model with the Principal Component Analysis (PCA) technique. The approach uses PCA to reduce the system’s dimensionality, minimizing the number of fuzzy rules required in the T–S [...] Read more.
In this work, a new nonlinear control method is proposed, which integrates the Takagi–Sugeno (T–S) fuzzy model with the Principal Component Analysis (PCA) technique. The approach uses PCA to reduce the system’s dimensionality, minimizing the number of fuzzy rules required in the T–S fuzzy model. This reduction not only simplifies the system variables but also decreases the computational complexity, resulting in a more efficient control with smooth transient responses and zero steady-state error. To validate the performance of this PCA-based approach for both system identification and control, an interconnected double-tank system was employed. The results demonstrate the method’s capacity to maintain control accuracy while reducing computational load, making it a promising solution for applications in industrial and engineering systems that require robust, efficient control mechanisms. Full article
(This article belongs to the Special Issue Fuzzy Control System: Design and Applications)
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16 pages, 754 KiB  
Article
Transfer Learning for Thickener Control
by Samuel Arce Munoz and John D. Hedengren
Processes 2025, 13(1), 223; https://doi.org/10.3390/pr13010223 - 14 Jan 2025
Viewed by 712
Abstract
Thickener control is a key area of focus in the minerals processing industry, particularly due to its crucial role in water recovery, which is essential for sustainable resource management. The highly nonlinear nature of thickener dynamics presents significant challenges in modeling and optimization, [...] Read more.
Thickener control is a key area of focus in the minerals processing industry, particularly due to its crucial role in water recovery, which is essential for sustainable resource management. The highly nonlinear nature of thickener dynamics presents significant challenges in modeling and optimization, making it a strong candidate for advanced surrogate modeling techniques. However, traditional data-driven approaches often require extensive datasets, which are frequently unavailable, especially in new plants or unexplored operational domains. Developing data-driven models without enough data representative of the dynamics of the system could result in incorrect predictions and consequently, unstable response of the controller. This paper proposes the application of a methodology that leverages transfer learning to address these data limitations to enhance surrogate modeling and model predictive control (MPC) of thickeners. The performance of three approaches—a base model, a transfer learning model, and a physics-informed neural network (PINN)—are compared to demonstrate the effectiveness of transfer learning in improving control strategies under limited data conditions. Full article
(This article belongs to the Special Issue Machine Learning Optimization of Chemical Processes)
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19 pages, 3623 KiB  
Article
Advancing Energy Recovery: Evaluating Torrefaction Temperature Effects on Food Waste Properties from Fruit and Vegetable Processing
by Andreja Škorjanc, Sven Gruber, Klemen Rola, Darko Goričanec and Danijela Urbancl
Processes 2025, 13(1), 208; https://doi.org/10.3390/pr13010208 - 13 Jan 2025
Viewed by 669
Abstract
Most organic waste from food production is still not used for energy production. From the perspective of energy production, one option is to valorise the properties of organic waste. The fruit juice industry is growing rapidly and generates large amounts of waste. One [...] Read more.
Most organic waste from food production is still not used for energy production. From the perspective of energy production, one option is to valorise the properties of organic waste. The fruit juice industry is growing rapidly and generates large amounts of waste. One of the main wastes in food and fruit juice processing is peach pits and apple peels. The aim of this study was to analyse the influence of torrefaction temperature on the properties of food waste, namely apple peels, peach pits and pea shells, in order to improve their energy value and determine their potential for further use and valorisation as a renewable energy source. The aim was to analyse the influence of different torrefaction temperatures on the heating value (HHV), mass yield (MY) and energy yield (EY) in order to better understand the behavior of the thermal properties of individual selected samples. The torrefaction process was carried out at temperatures of 250 °C, 350 °C and 450 °C. The obtained biomass was compared with dried biomass. For apple peels, HHV after torrefaction was (28 kJ/kg), MY decreased by (66–34%), while EY fell by (97–83%). Peach pits, despite a higher HHV after torrefaction (18 kJ/kg), achieved low MY (38–89%) and EY (59–99%), which reduces their efficiency in biochar production. Pea peels had EY (82–97%) and a lower HHV after torrefaction (11 kJ/kg), but their high ash content limits their wider use. The results confirm that, with increasing temperature, MY and EY for all selected biomasses decrease, which is a consequence of the degradation of hemicellulose and cellulose and the loss of volatile compounds. In most cases, increasing the torrefaction temperature improved the resistance to moisture adsorption, as this is related to the thermal process that causes structural changes. The results showed that the torrefaction process improved the hydrophobic properties of the biomass samples. Temperature was seen to have a great impact on mass energy efficiency. Apple peels generally had the highest mass and energy yield. Full article
(This article belongs to the Special Issue Novel Recovery Technologies from Wastewater and Waste)
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16 pages, 848 KiB  
Article
Coal Tar Naphtha Refining: Phenol Alkylation with 1-Hexene and the Impact of Pyridine
by Yuhan Xia and Arno de Klerk
Processes 2025, 13(1), 194; https://doi.org/10.3390/pr13010194 - 12 Jan 2025
Viewed by 736
Abstract
Coal tar naphtha is produced from coal carbonization, moving bed coal gasification, and thermal liquefaction of coal. The naphtha can contain up to 60% aromatics and 15% olefins, as well as nitrogen-, oxygen-, and sulfur-containing compounds. Usually only hydrotreating is considered, but when [...] Read more.
Coal tar naphtha is produced from coal carbonization, moving bed coal gasification, and thermal liquefaction of coal. The naphtha can contain up to 60% aromatics and 15% olefins, as well as nitrogen-, oxygen-, and sulfur-containing compounds. Usually only hydrotreating is considered, but when producing motor gasoline, olefin–aromatic alkylation could reduce the associated octane number loss due to olefin hydrogenation by converting olefins to alkylated phenols and aromatics. The plausibility of using acid-catalyzed alkylation with coal tar naphtha, which contains nitrogen bases, was investigated by studying a model system comprising phenol and 1-hexene in the absence and presence of pyridine. It was found that pyridine only inhibited conversion over a range of amorphous silica–alumina catalysts. The most effective catalyst was Siral 30 (30% silica, 70% alumina) and at 315 °C, 0.05 wt% pyridine caused a 35% inhibition of phenol conversion compared to conversion in the absence of pyridine. Catalyst activity could be restored by rejuvenating the catalyst with clean feed at a higher temperature. The results supported a description of phenol alkylation with olefins that took place by at least two pathways, one involving protonation of the olefin (typical for Friedel–Crafts alkylation) and one where the olefin is the nucleophile. Full article
(This article belongs to the Special Issue Synthesis, Catalysis and Applications of Organic Chemistry)
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22 pages, 4283 KiB  
Article
GIS-Driven Methods for Scouting Sources of Waste Heat for Fifth-Generation District Heating and Cooling (5GDHC) Systems: Railway/Highway Tunnels
by Stanislav Chicherin
Processes 2025, 13(1), 165; https://doi.org/10.3390/pr13010165 - 9 Jan 2025
Viewed by 716
Abstract
This paper explores the innovative application of Geographic Information Systems (GISs) to identify and utilize waste heat sources from railway and highway tunnels for fifth-generation district heating and cooling (5GDHC) systems. Increasing the number of prosumers—entities that produce and consume energy—within 5GDHC networks [...] Read more.
This paper explores the innovative application of Geographic Information Systems (GISs) to identify and utilize waste heat sources from railway and highway tunnels for fifth-generation district heating and cooling (5GDHC) systems. Increasing the number of prosumers—entities that produce and consume energy—within 5GDHC networks enhances their efficiency and sustainability. While potential sources of waste heat vary widely, this study focuses on underground car/railway tunnels, which typically have a temperature range of 20 °C to 40 °C. Using GIS software, we comprehensively analyzed tunnel locations and their potential as heat sources in Belgium. This study incorporates data from various sources, including OpenStreetMap and the European Waste Heat Map, and applies a two-dimensional heat transfer model to estimate the heat recovery potential. The results indicate that railway tunnels, especially in the southern regions of Belgium, show significant promise for waste heat recovery, potentially contributing between 0.8 and 2.9 GWh annually. The integration of blockchain technology for peer-to-peer energy exchange within 5GDHC systems is also discussed, highlighting its potential to enhance energy management and billing. This research contributes to the growing body of knowledge on sustainable energy systems and presents a novel approach to leveraging existing district heating and cooling infrastructure. Full article
(This article belongs to the Special Issue Novel Recovery Technologies from Wastewater and Waste)
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18 pages, 2849 KiB  
Article
A Two-Level Facility Layout Design Method with the Consideration of High-Risk Facilities in Chemical Industries
by Guanxin Xu, Siyu Xu and Yufei Wang
Processes 2025, 13(1), 161; https://doi.org/10.3390/pr13010161 - 9 Jan 2025
Viewed by 1158
Abstract
Understanding facility layout design in chemical industries requires multi-disciplinary knowledge and experience. The recent work mainly focuses on improving safety and calculating the efficiency of the design. However, in chemical industries, facilities are always located in frames, so both facility layout and frame [...] Read more.
Understanding facility layout design in chemical industries requires multi-disciplinary knowledge and experience. The recent work mainly focuses on improving safety and calculating the efficiency of the design. However, in chemical industries, facilities are always located in frames, so both facility layout and frame layout should be considered in the design, as well as safety. Such a situation has not been well studied. In this work, facilities are divided into several frames and then placed in a fixed area. The risk resources located in the frames and out of the frames are both contained, and the safety distances are compliant with relative regulations. Optimization and some heuristic rules are applied to obtain the layout of each frame and the whole plant. Moreover, fire embankments are considered to achieve a more realistic and reasonable final layout. As a result, compared with the initial one, the actual and potential safety factors and the reasonable degree of the factory layout are both improved. The total costs are reduced by 7.38 × 104 $·a−1. Through these steps, the effectiveness of the proposed approach is proven. Full article
(This article belongs to the Special Issue Process Systems Engineering-Incubating Sustainability for Industrial Revolution 4.0)
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