Search Results (8,863)

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer resins. Temperature variations can lead to the degradation of the exchange properties of these resins, primarily causing a decrease in their exchange capacity, which negatively impacts the efficiency of the brine purification. After multiple ion exchange regeneration cycles, significant quantities of spent resins may be generated. These must be managed in accordance with resource efficiency and hazardous waste management to ensure the sustainability of the industrial process. In this paper, a comparative study is conducted to characterize the long-term stability of a new commercial chelating resin used in the industrial electrolysis process. The spectroscopic methods of physicochemical characterization included: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The thermal behavior of the polymer resins was evaluated using the following thermogravimetric methods: thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), while the moisture behavior was studied using dynamic vapor sorption (DVS) analysis. To assess the energy potential, the polymer resins were analyzed to determine their calorific value and overall energy content. Full article

Environmental concerns about the widespread use of non-biodegradable plastic have generated interest in developing quick and effective methods to degrade synthetic polymers. With millions of tons of plastic waste generated annually, biodegradation by microorganisms presents a promising and eco-friendly solution. However, a bottleneck has arisen due to the lack of standardized methods for verification of the biodegradation process. Based on this literature review, he techniques most commonly employed for this purpose currently include measuring mass loss, examining the surface of plastic fragments by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and using analytical methods such as Fourier transform infrared spectroscopy (FTIR), pyrolysis–gas chromatography–mass spectrometry (Pyr-GC/MS) or high-performance liquid chromatography (HPLC). Each of these methods has its advantages and disadvantages. Nevertheless, currently, there is no universal approach to accurately assess the ability of individual microorganisms to degrade plastics. In this review, we summarize the latest advances in techniques for detecting biodegradation of synthetic polymers and future directions in the development of sustainable strategies for mitigating plastic pollution. Full article

Particleboards were developed by replacing a part of wood with various biomass residues, including coffee bean husks, spent coffee grounds, thistle, Sideritis and dead leaves of Posidonia oceanica. These materials were analysed to determine their physicochemical properties like the moisture content, pH, and buffer capacity, using standard laboratory techniques, while thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were also used for their further characterisation. The results revealed that all biomasses contained cellulose, hemicellulose, and lignin in varying proportions, along with differing degrees of crystallinity. To produce particleboards, the biomasses were bonded using two types of adhesives: (a) conventional urea-formaldehyde resin (UF) and (b) polymeric 4,4′-methylene diphenyl isocyanate (pMDI). Laboratory-scale, single-layer particleboards were manufactured simulating industrial production practices. These panels were evaluated for their mechanical and physical properties according to European standards. The findings showed a general reduction in mechanical performance when compared to conventional wood-based panels. However, panels made with coffee grounds and Posidonia showed improved resistance to thickness swelling after 24 h in water at 20 °C. Additionally, all experimental panels exhibited lower formaldehyde content than wood-based reference panels. This study demonstrated the feasibility of upcycling biomass residues as a sustainable alternative to virgin wood in the production of particleboard, providing a resource-efficient solution for specific interior applications within a circular economy framework. Full article

This study demonstrates the conversion of agricultural and industrial waste into construction materials by developing ultra-high-performance concrete using cold-bonded sesame ash and waste glass aggregates. The primary focus of this study was sustainability and waste valorization in self-curing concrete systems. This study focuses on many aspects of producing cementless concrete with superior short- and long-term properties, incorporating an innovative artificial aggregate premanufactured using sesame ash and waste glass. Prepacking technology of casting was used. A self-curing additive is used to reduce the energy required for curing. In cold-bonded aggregates (CBAs), the aggregate content ranged from 10 to 50% of the total sand volume. Polyethylene glycol was used as an internal curing agent to evaluate the mechanical properties of the concrete, including the compressive strength and tensile strength at different ages. The durability characteristics of the concrete were also analyzed in terms of its resistance to sulfates, chloride ion penetration, and performance at elevated temperatures of 300 and 600 °C. Microscopic analyses were conducted by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results showed a significant improvement in the mechanical and durability performance, especially at 30%, which resulted in the highest compressive strength of 147.2 MPa at 90 days. This is an 11.93% increase compared with that of the reference mix. The tensile strength was also improved by 14.5% at the same replacement ratio. The mix containing 30% manufactured aggregate demonstrated the best thermal resistance, retaining the highest percentage of residual strength at both 300 °C and 600 °C, as well as superior sulfate impact resistance, with a strength reduction factor of 39.5%. When the replacement ratio was increased to 50%, the chloride penetration resistance improved significantly by 41% compared with that of the reference mix. FTIR, TGA, and DSC analyses also demonstrated enhanced silicate polymerization and increased carbonate formation, contributing to the improved chemical stability and density of the concrete matrix. Full article

Biosurfactants have emerged as promising agents for environmental remediation due to their ability to complex, chelate, and remove heavy metals from contaminated environments. This review evaluates their potential for recovering critical minerals from waste materials to support renewable energy production, emphasizing the role of biosurfactant–metal interactions in advancing green recovery technologies and enhancing resource circularity. Among biosurfactants, rhamnolipids demonstrate a high affinity for metals such as lead, cadmium, and copper due to their strong stability constants and functional groups like carboxylates, with recovery efficiencies exceeding 75% under optimized conditions. Analytical techniques, including Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Fourier-Transform Infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM), are instrumental in assessing recovery efficiency and interaction mechanisms. The review introduces a Green Chemistry Metrics Framework for evaluating biosurfactant-based recovery processes, revealing 70–85% lower Environmental Factors compared to conventional methods. Significant research gaps exist in applying biosurfactants for extraction of metals like lithium and cobalt from batteries and other waste materials. Advancing biosurfactant-based technologies hold promise for efficient, sustainable metal recovery and resource circularity, addressing both resource scarcity and environmental protection challenges simultaneously. Full article

This study offers fresh insights into the technical and stylistic exchanges between Flemish and Portuguese panel painting during the late 15th and early 16th centuries. By comparing two contemporaneous works, we trace Flemish influence in Portugal through a detailed materials and techniques analysis. Non-invasive, in situ methods—including energy dispersive X-ray fluorescence (XRF), macro-photography (MP), infrared reflectography (IRR), and dendrochronology—were used to examine each painting’s wooden support, ground layer, underdrawing, and pigment stratigraphy. Select micro-sampling analyses—micro-Fourier-transform infrared spectroscopy (μ-FTIR), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and micro-Raman spectroscopy (µ-Raman)—provided complementary data on binder and pigment composition. While both paintings share nearly identical pigments and layering sequences and employ comparable coating techniques, their ground compositions differ subtly. Notably, the Flemish work features extensive gold-leaf application, whereas underdrawing execution takes on principal importance in the Portuguese example. Together, these findings reveal that Jorge Afonso’s workshop developed a distinct Portuguese method—rooted in Flemish practices disseminated by Quentin Metsys—yet adapted to local materials and aesthetic priorities. Full article

Organic dyes are pollutants that threaten aquatic life and human health. These dyes are used in various industries; therefore, recent research focuses on the problem of their removal from wastewater. The aim of this study is to examine the clay/gum arabic nanocomposite (CG/NC) as an adsorbent to adsorb methylene blue (MB) and crystal violet (CV) dyes from synthetic wastewater. The CG/NC was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunaure–Emmett–Teller (BET). The effect of parameters that may influence the efficiency of removing MB and CV dyes was studied (dosage of CG/NC, contact time, pH values, initial concentration, and temperature), and the optimal conditions for removal were determined. Furthermore, an artificial neural network (ANN) model was adopted in this study. The results indicated that the adsorption behavior adhered to the Langmuir model and conformed to pseudo-second-order kinetics. The results also indicated that the removal efficiency reached 99%, and q_max reached 66.7 mg/g and 52.9 mg/g for MB and CV, respectively. Results also proved that CG/NC can be reused up to four times with high efficiency. The ANN models proved effective in predicting the process of the removal, with low mean squared errors (MSE = 1.824 and 1.001) and high correlation coefficients (R² = 0.945 and 0.952) for the MB and CV dyes, respectively. Full article

This study investigates the potential of biochars derived from agricultural waste biomass for the removal of heavy metal ions from aqueous solutions. Biochars were produced via slow pyrolysis at 793 K using almond shells (AS), walnut shells (WS), pistachio shells (PS), and rice husks (RH) as feedstocks. The physicochemical properties and adsorption performance of the resulting materials were evaluated with respect to Cd(II), Mn(II), Co(II), Ni(II), Zn(II), total Iron (Fe_tot), total Arsenic (As_tot), and total Chromium (Cr_tot) in model solutions. Surface morphology, porosity, and surface chemistry of the biochars were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K (for specific surface area and pore structure), Fourier-transform infrared spectroscopy (FTIR), and determination of the point of zero charge (pH_pzc). Based on their textural properties, biochars derived from WS, PS, and AS were classified as predominantly microporous, while RH-derived biochar exhibited mesoporous characteristics. The highest Brunauer–Emmett–Teller (S_BET) surface area was recorded for PS biochar, while RH biochar showed the lowest. The pistachio shell biochar exhibited the highest specific surface area (440 m²/g), while the rice husk biochar was predominantly mesoporous. Batch adsorption experiments were conducted at 25 °C, with an adsorbent dose of 3 g/L and a contact time of 24 h. The experiments in multicomponent systems revealed removal efficiencies exceeding 87% for all tested metals, with maximum values reaching 99.9% for Cd(II) and 97.5% for Fe_tot. The study highlights strong correlations between physicochemical properties and sorption performance, demonstrating the suitability of these biochars as low-cost sorbents for complex water treatment applications. Full article

Background-Objectives: Chronic diseases linked to inflammation, such as cardiovascular disease (CVD) and cancer, continue to pose major public health challenges due to their high mortality rates. There is growing interest in natural bioactive compounds, particularly those derived from plants, as potential therapeutic or preventive agents due to their low toxicity profiles. This study aimed to explore two freshwater plants—Nelumbo nucifera (Indian lotus) and Lemna sp.—as potential sources of bioactive compounds with antioxidant, anti-inflammatory, and antithrombotic properties. While N. nucifera has established but incompletely characterized biofunctional properties, Lemna sp. remains largely unexplored in this context. Methods: Amphiphilic extracts from both plant species were analyzed for phenolic and lipid constituents, including unsaturated fatty acids, polar lipids, and carotenoids. Antioxidant capacity was evaluated using DPPH, ABTS, and FRAP assays. Anti-inflammatory and antithrombotic activities were assessed via platelet aggregation assays using PAF and ADP agonists. Structural characterization was performed using Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography–mass spectroscopy (LC-MS) to support structure–activity relationship (SAR) analysis. Results: Extracts, particularly from Lemna sp., showed potent antiplatelet activity against PAF and ADP. LC-MS revealed the presence of polar lipids rich in monounsaturated and omega-3 polyunsaturated fatty acids, with a favorable omega-6/omega-3 ratio, especially in Lemna sp., correlating with strong anti-inflammatory potential. High levels of total phenolics and carotenoids were observed, aligning with substantial antioxidant capacity in both species. Conclusions: These findings suggest that N. nucifera and Lemna sp. are promising sources of bioactive compounds with potential applications in functional foods, cosmetics, and pharmaceuticals targeting inflammation- and thrombosis-related chronic diseases. Further studies are warranted to confirm their safety and efficacy. Full article

This study assessed the growth performance of red palm weevil (RPW) (Rhynchophorus ferrugineus: Curculionidae) larvae on a liquid diet of yeast-enriched potato dextrose broth (control) and on diets with added polystyrene and polyurethane. For 15 days of diet exposure, the growth and survival, plastic degradation, and gut microbiota of larvae were examined. RPWs showed higher survival rates under polystyrene and polyurethane treatments than in the control group. Head diameter showed a higher trend under polyurethane treatment than under the other treatments. Treated plastics were partly degraded after a 15-day exposure. Further analysis of plastic residues from frass revealed significant differences in Fourier Transform Infrared Spectroscopy (FTIR), with decreased intensity of characteristic peaks compared to frass from larvae fed in the control. Gut bacterial communities in the gut of RPW larvae showed that plastic feeding did not significantly alter the presence of key microbial taxa, but members of Firmicutes and Proteobacteria were higher in the plastic treatment, showing preliminary signs of plastic oxidation and degradation. Overall, these findings provide evidence that ingestion of PS and PU by RPW larvae supports their survival and alters their gut microbiota, possibly due to plastic degradation, paving the way for further research into the interactions between RPWs, their microbiome, and key functional activities, with implications for plastic waste management and recycling. Full article

An aqueous leaf extract of Egeria densa was used to green-synthesize iron (II) and iron (III) oxide nanoparticles from ferrous sulphate and ferric chloride, respectively. The successful green synthesis of the nanoparticles was confirmed through UV–visible spectroscopy, and the colour of the mixtures changed from light-yellow to green-black and reddish-brown for FeO–NPs and Fe₂O₃–NPs, respectively. The morphological characteristics of the nanoparticles were determined using an X-ray diffractometer (XRD), a Fourier transform infrared spectrophotometer (FTIR), a transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy (EDX). The UV–Vis spectrum of the FeO–NPs showed a sharp peak at 290 nm due to the surface plasmon resonance, while that of the Fe₂O₃–NPs showed a sharp peak at 300 nm. TEM analysis revealed that the FeO–NPs were oval to hexagonal in shape and were clustered together with an average size of 18.49 nm, while the Fe₂O₃-NPs were also oval to hexagonal in shape, but some were irregularly shaped, and they clustered together with an average size of 27.96 nm. EDX analysis showed the presence of elemental iron and oxygen in both types of nanoparticles, indicating that these nanoparticles were essentially present in oxide form. The XRD patterns of both the FeO–NPs and Fe₂O₃–NPs depicted that the nanoparticles produced were crystalline in nature and exhibited the rhombohedral crystal structure of hematite. The FT-IR spectra revealed that phenolic compounds were present on the surface of the nanoparticles and were responsible for reducing the iron salts into FeO–NPs and Fe₂O₃–NPs. Conclusively, this work demonstrated for the first time the ability of Elodea aqueous extract to synthesize iron-based nanoparticles from both iron (II) and iron (III) salts, highlighting its versatility as a green reducing and stabilizing agent. The dual-path synthesis approach provides new insights into the influence of the precursor oxidation state on nanoparticle formation, thereby expanding our understanding of plant-mediated nanoparticle production and offering a sustainable route for the fabrication of diverse iron oxide nanostructures. Furthermore, it provides a simple, cost-effective, and environmentally friendly method for the synthesis of the FeO–NPs and Fe₂O₃–NPs using Egeria densa. Full article

Extensive research has been conducted on the catalytic properties of molybdenum disulfide (MoS₂) materials in the context of the hydrogen evolution reaction (HER). This study focuses on exploring hybrid MoS₂/Au structures as a catalyst for HER, utilizing linear sweep voltammetry as the experimental methodology. Firstly, 2D-MoS₂ flakes were synthesized by the chemical vapor deposition (CVD) approach and directly added to gold nanoparticles during or after their preparation process. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy with energy-dispersive X-ray analysis (SEM/EDX). The HER performance was tested for the two resulting samples to show that the preparation of gold nanoparticles with the coexistence of CVD-MoS₂ flakes produces a superior electrocatalytic performance of the sample in a neutral medium. Notably, the onset potential was measured as −0.152 V (versus reversible hydrogen electrode (RHE)) with an exchange current density (j₀) of 0.22 mA/cm². Chronoamperometric data show that all composites retained initial current densities for 15 hours, confirming stable, efficient HER performance post-decay. Full article

Wood adhesives play a critical role in the wood processing industry; however, traditional formaldehyde-based adhesives pose health risks and are reliant on non-renewable resources. This study aims to develop a bio-based wood adhesive with excellent water resistance, focusing on environmentally friendly solutions. The synthesis of an oxidized starch-lignin (OSTL) composite adhesive was accomplished by modifying starch via oxidation and subsequent cross-linking with lignin. Ammonium persulfate (APS) was employed for oxidation of starch, introducing aldehyde groups that upgrade its reactivity with lignin. Subsequently, the oxidized starch (OST) was cross-linked with the phenolic rings of lignin, resulting in a strong network structure. The oxidation of starch and its cross-linking mechanism with lignin were investigated using the Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), and X-ray photoelectron spectroscopy (XPS) techniques, proving the formation of aldehyde and carboxyl groups with subsequent reaction possibilities. The effects of oxidant dosage, oxidation time, and the ratio of starch to lignin on the adhesive properties were systematically studied. The results demonstrated that the OSTL adhesive, prepared under optimized conditions, exhibited outstanding adhesion strength (1.23 MPa in dry state) and water resistance (0.94 MPa after 24 h cold water immersion, 1.04 MPa after 3 h in hot water, and 0.69 MPa after 3 h in boiling water), significantly outperforming conventional wood adhesives in terms of cold water, hot water, and boiling water resistance. In addition, the thermal behavior of the OSTL adhesive was further validated using differential scanning calorimetry (DSC) as well as thermogravimetric analysis (TGA). This study presents new insights and technical support for the development of green, environmentally friendly, and highly water-resistant lignin-based bio-adhesives. Full article

The delayed healing and infection risks associated with chronic wounds and burns pose significant clinical challenges. Traditional dressings provide basic coverage but lack the bioactive properties needed for tissue regeneration and antimicrobial protection. In this study, we developed zinc alginate hydrogel-coated traditional wound dressings (WD@AlgZn) and evaluated their physicochemical properties, antimicrobial performance, and in vivo healing efficacy. Scanning electron microscopy (SEM) revealed a uniform coating of the zinc alginate network on dressing fibers, while Fourier-transform infrared spectroscopy (FT-IR) confirmed the successful incorporation of zinc ions. Antimicrobial assays further demonstrated that WD@AlgZn reduced bacterial loads (CFU/mL counts) by several orders of magnitude for both Staphylococcus aureus and Escherichia coli compared to uncoated controls. An in vivo rat burn wound model exhibited accelerated wound closure when using WD@AlgZn dressings compared to conventional wound care approaches, achieving a 90.75% healing rate by day 21, significantly outperforming the silver sulfadiazine (52.32%), uncoated-dressing (46.58%), and spontaneous-healing (37.25%) groups. Histological analysis confirmed enhanced re-epithelialization, neovascularization, and reduced inflammation in WD@AlgZn-treated tissues. The findings suggest that WD@AlgZn offers a promising alternative for advanced wound management, combining structural robustness with bioactive properties to support efficient wound healing and infection control. These results provide valuable insights into the potential clinical applications of metal-ion cross-linked biopolymeric hydrogel dressings for next-generation wound care strategies. Full article

Piezoelectric polyvinylidene fluoride (PVDF) film sensors embedded in a tire can make the tire have a sense of tactile. Thus, PVDF strain sensors play an important role in smart tires. However, temperature tolerance of PVDF is a key issue limiting its application in smart tire as the embedding process needs high temperature vulcanization. This paper proposes a film repolarization method to treat PVDF film materials after high temperature vulcanization, which can be implemented to apply in smart tire. Variation in piezoelectric properties and its changing mechanism of PVDF film are analyzed with the methods of X-Ray Diffraction Spectroscopy (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Vulcanization process that PVDF film sensors undergo in tire applications are simulated. Furthermore, properties of the PVDF sensors with different process stages are simulated based on finite element model. An experimental platform of the PVDF sensors is set up and the drop rod experiments are conducted. Results verify the performance improvement of the repolarization strategy on embedded PVDF sensors. The effectiveness of the repolarization in the PVDF film shows a great significance for the application of strain sensors in smart tire. Full article