Search Results (169)

The propagation of high-frequency ultrasound waves will generate both physical and chemical effects as they propagate through a liquid medium, such as acoustic streaming, an acoustic fountain, and atomization. These phenomena are believed to be the main factors that contribute to the enhancement of mass transfer in the gas–liquid carbon dioxide (CO₂) absorption system. Computational Fluid Dynamic (CFD) simulation is one of the powerful tools that can be used to model the complex hydrodynamic behavior induced by the propagation of ultrasound waves in the liquid medium. In this study, the ultrasonic irradiation forces were simulated via the momentum source term method using commercial CFD software (ANSYS Fluent V19.1). In addition, a parametric study was conducted to investigate the influences of absorber height and ultrasonic power on the hydrodynamic mixing performance. The simulation results indicated that enhanced mixing and a higher intensification factor were achieved with increased fountain flow velocity, particularly at the lowest absorber height and highest ultrasonic power. Conversely, the energy efficiency was improved with the increase of absorber height and decrease of ultrasonic power. To determine the optimal combination of absorber height and ultrasonic power, this trade-off between the energy efficiency and intensification in the ultrasonic-assisted absorption system (UAAS) is a crucial consideration during process scale-up. Full article

The conventional urea-based process for hydrazine hydrate production faces challenges including low product yield and high energy consumption. To overcome these limitations, we propose an innovative integrated approach combining jet reactor technology with membrane separation, further enhanced through heat network optimization. Through process simulation and sensitivity analysis, the following optimal distillation parameters were identified: nine theoretical stages, feed entry at the fifth stage, a reflux ratio of 0.6, and a distillate flow rate of 354 kg/h. Systematic optimization of the heat exchanger network (HEN) using pinch technology achieved substantial energy savings, reducing hot utility consumption by 66.8% (to 1317 MJ/h) and cold utility usage by 62.7% (to 1503 MJ/h). The redesigned HEN prioritized temperature-cascaded heat recovery, enabling 67% energy recuperation from exothermic reaction streams. Operational costs decreased by 12%, underscoring the economic viability of coupling process intensification with thermal integration. This work establishes a sustainable framework for hydrazine hydrate synthesis, balancing industrial feasibility with reduced environmental impact in chemical manufacturing. Full article

The water-based binder has the advantages of non-toxic, non-flammable, small odor, and no pollution to the environment. However, there are problems such as low bond strength and poor battery cycle life of commonly used binders on the market. In this paper, the acrylic binder is modified. In addition, acrylic acid/methacrylic acid, acrylonitrile, and octadecyl acrylate/octadecyl methacrylate are copolymerized at high temperature, and a new binder for graphite anode is successfully developed. The binder can significantly improve the affinity between the graphite anode and the electrolyte and the integrity of the graphite particles during the cycle, so that the battery has better electrochemical performance. During the charge and discharge cycle of 1 C, the graphite anode coated with PAANa as a binder was able to cycle 360 cycles and remain stable, which is far better than the 192 cycles of the commercial binder LA133. It is proved that the experimental formula has a certain commercial application prospect. Full article

To address the environmental pressures and resource waste caused by massive stockpiling of steel slag, this study developed a carbonated steel slag pervious concrete binder using 40% steel slag powder as the primary cementitious component combined with CaO and MgO. The mechanical performance evolution was investigated, while XRD, SEM, and TG-DTG microcharacterization techniques were employed to reveal the carbonation mechanism and strength formation principles. The results demonstrate that when CaO and MgO contents reached 5% and 15%, respectively, the 28d compressive strength of mortar increased by 134.49% compared to the reference group. Microstructural analysis confirmed that CaO reacted to form CaCO₃ crystals, while MgO enhanced strength by regulating CaCO₃ crystal morphology to optimize product structure. Using steel slag as an aggregate, carbonated steel slag pervious concrete was prepared to investigate the influence mechanisms of B/A ratio and W/B ratio on compressive strength, permeability coefficient, and carbonation effects. The post-carbonation strength increase was adopted to evaluate carbonation efficiency. Increasing B/A ratio enhanced paste filling in aggregate voids, raising 28d compressive strength to 24.76 MPa, but thickened paste coating layers reduced permeability coefficient to 0.33 mm/s while impeding CO₂ diffusion, decreasing carbonation strength growth rate by 22.76%. Initial W/B ratio elevation improved workability to increase strength to 23.76 MPa, whereas excessive water caused paste sedimentation and strength reduction. As W/B ratio rose, permeability coefficient decreased by 65.6%, while carbonation strength growth rate increased. The carbonated steel slag pervious concrete contained approximately 82% steel slag, demonstrating high resource utilization efficiency of steel slag and significant potential for carbon emission reduction. Full article

The increase in CO₂ emissions has been identified as a core driving factor in the intensification of the greenhouse effect. In order to achieve the dual-carbon vision, research on CO₂ capture and its catalytic conversion is receiving growing attention. Due to the high chemical stability of CO₂ itself, traditional separation technologies find it difficult to capture it onto catalysts. Currently, using hydrocarbons as carriers for catalytic reactions is the most common and efficient method. In recent years, metal-organic frameworks (MOFs) have shown their irreplaceable importance in CO₂ capture and catalytic conversion due to their unique adjustable and controllable pore structures and multiple active sites. This study integrates various classification criteria of MOFs, proposes a cooperative mechanism between metal doping and functional groups, and also reveals the CO₂ capture and catalytic conversion processes. In addition, we have conducted an in-depth discussion on the future development of continuous-flow microreactor technology and provided performance and property relationship diagrams for multiple MOF series, offering valuable reference material for future research in related fields. Full article

The current work investigates the intensification process of the biological oxidation (BO) of a pharmaceutical effluent using ultrasound (US)-based pretreatment methods. US, in combination with chemical oxidants, like hydrogen peroxide (H₂O₂), Fenton, potassium persulphate (KPS), and peroxone, was used as a pretreatment technique to enhance the efficacy of BO, as BO alone could only bring about 16.67% COD reduction. The application of US under the optimized conditions of a 70% duty cycle, 120W of power, pH 2, and at a 30 °C temperature resulted in 12.3% COD reduction after 60 min, whereas its combination with oxidants at optimized loadings resulted in a higher COD reduction of 20% for H₂O₂ (2000 ppm), 23.08% for Fenton (1:1 Fe:H₂O₂), and 30.77% for the US + peroxone approach (400 mg/h of ozone with 2000 ppm H₂O₂). The pretreated samples did not produce any toxic by-products, as confirmed by a toxicity analysis using the agar well diffusion method. A cow-dung-based sludge was acclimatised specifically for use in BO. The treatment time for BO was set to 8 h, and the US + peroxone-pretreated samples showed a maximum overall COD reduction of 60%, which is about three times that observed with only BO. This work clearly demonstrates the enhancement of the biodegradation of a complex recalcitrant pharmaceutical effluent using a US-based pretreatment. Full article

The increasing global demand for food caused by a growing world population has resulted in environmental problems, such as the destruction of ecologically significant biomes and pollution of ecosystems. At the same time, the intensification of crop production in modern agriculture has led to the extensive use of synthetic fertilizers to achieve higher yields. Although chemical fertilizers provide essential nutrients and accelerate crop growth, they also pose significant health and environmental risks, including pollution of groundwater and other bodies of water such as rivers and lakes. Soils that have been destabilized by indiscriminate clearing of vegetation undergo a desertification process that has profound effects on microbial ecological succession, impacting biogeochemical cycling and thus the foundation of the ecosystem. Tropical countries have positive aspects that can be utilized to their advantage, such as warmer climates, leading to increased primary productivity and, as a result, greater biodiversity. As an eco-friendly, cost-effective, and easy-to-apply alternative, biofertilizers have emerged as a solution to this issue. Biofertilizers consist of a diverse group of microorganisms that is able to promote plant growth and enhance soil health, even under challenging abiotic stress conditions. They can include plant growth-promoting rhizobacteria, arbuscular mycorrhizal fungi, and other beneficial microbial consortia. Bioremediators, on the other hand, are microorganisms that can reduce soil and water pollution or otherwise improve impacted environments. So, the use of microbial biotechnology relies on understanding the relationships among microorganisms and their environments, and, inversely, how abiotic factors influence microbial activity. The recent introduction of genetically modified microorganisms into the gamut of biofertilizers and bioremediators requires further studies to assess potential adverse effects in various ecosystems. This article reviews and discusses these two soil correcting/improving processes with the aim of stimulating their use in developing tropical countries. Full article

Low-temperature Fischer–Tropsch (LTFT) synthesis converts syngas to diesel/wax at 200–250 °C. The LTFT reaction has recently received renewed interest, as it can be used for converting syngas from renewable sources (biomass and waste) to high-value fuels and chemicals. Conventional LTFT reactors, such as fixed-bed and slurry reactors, are not entirely suitable for bio-syngas conversion due to their smaller scale compared to fossil fuel-based syngas processes. This review explores advancements in intensifying LTFT reactors suitable for bio-syngas conversion, enabling smaller scale and dynamic operation. Various strategies for enhancing heat and mass transfer are discussed, including the use of microchannel reactors, structured reactors, and other designs where either one or both the heat and mass transfer are intensified. These technologies offer improved performance and economics for small LTFT units by allowing flexible operation, with increased syngas conversion and reduced risk of overheating. Additionally, this review presents our outlook and perspectives on strategies for future intensification. Full article

Microbial fuel cell (MFC) is a bioelectrochemical device for biomass power generation, and the anode material determines the performance of the MFC. In this study, a novel anode material, which is a combination of graphite oxide/polythiophene (GO/Pth), was prepared on a carbon felt (CF) substrate and exhibited excellent capacitive performance. The MFC equipped with the CF/GO/Pth anode achieved a significant increase in power density, reaching a maximum value of 2.9 W/m³, which is a 3.32-fold increase in power density compared to that of the CF anode. Meanwhile, the CF/GO/Pth anode stored charge Q_t value was as high as 11,258.68 C/m², which was 4.13 times higher than that of the CF anode (2727.66 C/m²). High-throughput analysis showed that the percentage of charge-producing bacteria on the surface of the CF/GO/Pth anode was more than 90%, which was significantly higher than that of the charge-producing bacteria attached to the CF anode. This further confirms the significant enhancement of MFC performance by materials such as GO and Pth coated on the CF surface. In this study, CF/GO/Pth anode materials were prepared to successfully enhance the power output and charge storage capacity of MFC, and they also showed broad application prospects in the degradation of polluted waste liquids. Full article

Microbial fuel cells (MFCs) are a novel bioenergy technology that utilizes microorganisms to catalyze the conversion of fuels into electricity. However, traditional MFCs are constrained by the low electricity generation capacity of microorganisms, resulting in relatively low power output. Additionally, the inability of traditional MFCs to store electricity significantly limits their practical applications. In this study, we fabricate a novel oxide graphite/nickel cobalt oxide (GO/NiCo₂O₄) capacitive composite bioanode material supported on stainless-steel fiber felt (SSFF). This composite material combines the excellent biocompatibility of graphite oxide and the energy storage capacity of nickel cobalt oxide. Consequently, the prepared anode exhibits significant advantages, including high specific capacitance, efficient electron transport, and enhanced biocompatibility. The MFC with the SSFF/GO/NiCo₂O₄ anode demonstrated a significantly enhanced power density, achieving a maximum of 1267.5 mW/m²—1.38-fold and 2.23-fold higher than those of the SSFF/GO and SSFF anodes, respectively. Moreover, the modified anode (SSFF/GO/NiCo₂O₄) exhibited a stored charge (Q_s) of 1405.35 C/m², representing 2.61-fold and 35.79-fold increases compared to the SSFF/GO and SSFF anodes, respectively. High-throughput analysis revealed that SSFF/GO/NiCo₂O₄-modified anode achieved an electrogenic bacterial efficiency exceeding 81%, which was significantly higher than that of the SSFF/GO and SSFF anodes. The results of this study not only provide valuable insights and theoretical guidance for the development of MFCs using capacitive composite anode materials, they also present sustainable power solutions for low-power electronic systems, such as miniaturized sensors and IoT devices. Full article

Microbial fuel cell (MFC) technology has become a novel and attractive method for generating renewable energy during wastewater treatment. In this study, researchers combined carbon felt (CF), metal oxide (NiO), and polyaniline (PANI) to prepare CF/NiO/PANI multilayer capacitive bioelectrodes. The MFC equipped with a CF/NiO/PANI bioanode has a peak power density of 1988.31 ± 50.96 mW/m², which is 3.8 times higher than that of the MFC with a bare CF electrode, having a peak power density of 518.29 ± 27.07 mW/m². Charge–discharge cycle tests show that the storage charge capacity of the CF/NiO/PANI bioanode is 3304.64 C/m², which is 10.5 times greater than that of the bare CF anode. The electrochemical, morphological, and chemical properties of the prepared anodes are characterized using techniques such as SEM, EDS, FTIR, XPS, and XRD. Notably, high-throughput sequencing reveals that electrogenic bacteria account for 79.2% of the total microbial population on the CF/NiO/PANI multilayer capacitive bioelectrode. The synergistic effects of the composite materials result in the formation of a richer biofilm on the electrode surface, providing more active sites and enhancing capacitive characteristics. This innovative approach significantly improves the output power and peak current of MFCs, while also endowing the electrode with dual functions of simultaneous power generation and energy storage. Full article

Fluidized bed-chemical vapor deposition (FB-CVD) technology stands as a cross-cutting achievement of fluidized bed technology in chemical engineering and chemical vapor deposition (CVD) in materials science, finding applications in particle coating, granulation, and material preparation. As compared to conventional CVD technology, FB-CVD distinguishes itself through enhanced heat/mass transfer efficiency, achieving a uniform coating layer while maintaining low production costs. Given the related research on FB-CVD micro-nano particle coating, the mechanism of particle fluidization and chemical vapor deposition, and the difficulty of micro-nano particle agglomeration were summarized. The process intensification of micro-nano particle fluidization assisted by particle design and external force field, such as vibration field, magnetic field, and sound field, and micro-nano particle chemical vapor deposition coating were summarized. In particular, applications of FB-CVD micro-nano particle coating are introduced. Finally, the opportunities and challenges faced by FB-CVD micro-nano particle coating technology are discussed, and the development prospect of this technology is prospected. This review is beneficial for the researchers of the fluidization field, and also the particle coating technology. Full article

Additive manufacturing must be highlighted as an innovative technology with the capacity to produce objects with complex and customized geometries using a diverse range of raw materials. Despite its significant potential, research compiling and evaluating the specific contributions of additive manufacturing in the field of chemical engineering was scarce in both quantitative and qualitative terms. Similarly, the application of chemical engineering tools to additive manufacturing has not been specifically reviewed. Therefore, this work conducted a comprehensive review of the scientific literature covering these issues using bibliometric analysis. The search encompassed the entirety of the scientific literature up to the year 2023, yielding 3761 documents in the Scopus database. The principal findings of this bibliometric analysis indicated an exponential growth in the number of publications, which suggests a rising scientific interest in this field. The analysis revealed that English was the dominant language in the documents, and articles constituted the most common document type, indicating the quality and maturity of the research. The thematic distribution proved to be multidisciplinary, with a primary focus on engineering and materials science, as well as basic sciences. The United States was the foremost contributor to scientific production, followed by China and Germany. Keyword analysis and scrutiny of the most cited documents enabled the identification of the main topics, which were found to include biofabrication and biomedical applications. Moreover, bibliometric network analysis using the software SciMAT (v 1.1.06) yielded the corresponding strategic diagrams, evolution maps, and thematic networks, which provided a comprehensive overview of trends and research gaps. The considerable interest in the application of additive manufacturing to biofabrication and other biomedical purposes has overshadowed the specific applications within the chemical engineering field, while the potential contributions that chemical engineering could make to the field of additive manufacturing have been eclipsed too. On the one hand, applications focused on process intensification in chemical engineering could benefit from additive manufacturing to design advanced microreactors and other miniaturized devices or to produce more efficient heat exchangers, catalysts, and adsorbents with complex geometries and separation membranes with innovative materials and structures. On the other hand, life cycle assessment and optimization are established chemical engineering tools that should be more extensively employed in the context of additive manufacturing to ensure a more sustainable outcome. Full article

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

The large-scale application of aromatic polyamide (PA) thin-film composite (TFC) membranes for reverse osmosis has provided an effective way to address worldwide water scarcity. However, the water permeability and salt rejection capabilities of the PA membrane remain limited. In this work, cyclic micropores based on crown ether were introduced into the PA layer using a layer-by-layer interfacial polymerization (LbL-IP) method. After interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC), the di(aminobenzo)-18-crown-6 (DAB18C6) solution in methanol was poured on the membrane to react with the residual TMC. The cyclic micropores of DAB18C6 provided the membrane with rapid water transport channels and improved ion rejection due to its hydrophilicity and size sieving effect. The membranes were characterized by FTIR, XPS, SEM, and AFM. Compared to unmodified membranes, the water contact angle decreased from 54.1° to 31.6° indicating better hydrophilicity. Moreover, the crown ether-modified membrane exhibited both higher permeability and enhanced rejection performance. The permeability of the crown ether-modified membrane was more than ten times higher than unmodified membranes with a rejection above 95% for Na₂SO₄, MgSO₄, MgCl_2, and NaCl solution. These results highlight the potential of this straightforward surface grafting strategy and the modified membranes for advanced water treatment technologies, particularly in addressing seawater desalination challenges. Full article