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Search Results (1,080)

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0 pages, 948 KB  
Conference Report
Abstracts of the 1st International Online Conference on Environment
by Sergio Ulgiati
Environ. Earth Sci. Proc. 2026, 42(1), 25; https://doi.org/10.3390/eesp2026042025 - 18 Aug 2026
Abstract
The 1st International Online Conference on Environments addresses issues of environmental understanding, management, and restoration. Sessions ranged from general frameworks to a broad area of specific investigations: heavy metal removal using inactive yeast, gadolinium’s aquatic toxicity, adsorptive removal of pollutants, energy recovery from [...] Read more.
The 1st International Online Conference on Environments addresses issues of environmental understanding, management, and restoration. Sessions ranged from general frameworks to a broad area of specific investigations: heavy metal removal using inactive yeast, gadolinium’s aquatic toxicity, adsorptive removal of pollutants, energy recovery from waste and wastewater treatment, recycled carbon fibers, climate-resilient urban development, renewable biofuel production, green hydrogen, anthropogenic and volcanic CO2 emissions, quantifying aging dignity in urban ecosystems and stray dogs as pollution health sentinels. Keynotes covered digital plant phenotyping for restoration, microplastic dynamics, agricultural residue management, carbon credits, air quality, atmospheric pollution, transitional waters, green chemistry, ecotoxicity, micropollutants, and coastal darkening effects on plankton, among others. Applied solutions included phytoremediation of eutrophication in urban streams, circular approaches in aquaculture, biochar for wastewater treatment, AI-assisted mangrove monitoring, and true-cost accounting for food systems. The conference demonstrated that effective environmental policy requires the integration of laboratory findings, field restoration, and shared resource responsibility across terrestrial and marine ecosystems. Full article
(This article belongs to the Proceedings of The 1st International Online Conference on Environments)
23 pages, 14397 KB  
Article
Sustainable Approach of Mineral Dispersion Recovery from the Technological Wastewater Resulting from Porcelain Manufacturing
by Simona Elena Avram, Lucian Barbu Tudoran, Gheorghe Borodi, Miuta Rafila Filip, Raluca Anca Mereu and Ioan Petean
Sustainability 2026, 18(16), 8477; https://doi.org/10.3390/su18168477 - 18 Aug 2026
Abstract
Porcelain manufacturing technological wastewater contains many mineral particles, like kaolinite 27%, quartz 29%, calcium feldspar 15%, and mullite 12%. These particulate matters are dispersed into the wastewater from all technological steps influencing the water parameters, such as pH, electrical conductivity, total dissolved solids [...] Read more.
Porcelain manufacturing technological wastewater contains many mineral particles, like kaolinite 27%, quartz 29%, calcium feldspar 15%, and mullite 12%. These particulate matters are dispersed into the wastewater from all technological steps influencing the water parameters, such as pH, electrical conductivity, total dissolved solids (TDS) and turbidity. These properties were measured and correlated with the physicochemical investigation of the collected particles. The two sample types are as follows: particles collected directly from the wastewater dispersion (WWS) and the slurry (SLR) collected from the dump. The mineral distribution was assessed by XRD correlated with mineralogical optical microscopy, revealing the relative distribution of the finest kaolinite particles with respect to quartz and feldspar boulder-like particles. Mullite was observed as a rounded inclusion occurring due to the re-circulated grounded material. It results in the presence of sodium silicate, acting as a densification binder when the samples are completely dried. Particle morphology was correlated with their elemental composition through SEM–EDX investigation. Iron hydroxide was found at about 9%. It prevents re-circulation of this wastewater slurry in porcelain production. Thus, a sustainable approach is required for its utilization as a sub-product. Therefore, the samples were subjected to thermal analysis in order to reveal its sintering behavior. Thermal analysis revealed the dehydroxylation of kaolinite between 530 and 630 °C, and a high-temperature thermal event at 994 °C (WWS) and 997 °C (SLR), which was further confirmed by DSC and attributed to mullite formation. Particle consolidation through the dehydroxylated kaolinite matrix and further mullitized mass was assessed through SEM microscopy, indicating proper densification to ensure slurry utilization for less pretentious ceramic products, allowing them to be fired at relatively lower temperature than porcelain (e.g., 600–800 °C) and ensuring a significant energy consumption saving. Full article
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26 pages, 11944 KB  
Article
Electrospinning Combined with Microfluidic Coating for Preparation of PVP-Based Composite Nanofiber Membranes and Their Adsorption and Recycling Performance for Acidic Heavy Metals
by Si-Qi Wang, Qian-Yu Yuan, Ching-Wen Lou, Bing-Chiuan Shiu and Jia-Horng Lin
Processes 2026, 14(16), 2592; https://doi.org/10.3390/pr14162592 - 14 Aug 2026
Viewed by 275
Abstract
In the present work, polyvinylpyrrolidone (PVP) was selected as the primary raw material and fully dissolved in N,N-dimethylformamide (DMF) solvent. Hydroxymethyl cellulose (HMC), acrylic acid (AA) monomer with outstanding chelating performance, and UR were added in sequence. On this basis, composite nanofiber membrane [...] Read more.
In the present work, polyvinylpyrrolidone (PVP) was selected as the primary raw material and fully dissolved in N,N-dimethylformamide (DMF) solvent. Hydroxymethyl cellulose (HMC), acrylic acid (AA) monomer with outstanding chelating performance, and UR were added in sequence. On this basis, composite nanofiber membrane substrates of PVP/AA/HMC/UR were fabricated by means of electrospinning. Afterwards, silane coupling agent KH-560 was blended with polylactic acid (PLA). A uniform PLA/KH-560 functional coating was covered on the surface of the as-prepared nanofiber membrane via microfluidic coating treatment, and the target composite nanofiber adsorbent was ultimately obtained. Relevant performance characterization results indicated that moderate addition of HMC could greatly optimize the tensile strength of the membrane material, whereas excessive HMC dosage would cause a deterioration in mechanical strength. Moreover, the breaking elongation presented a slight declining trend, and the integrated mechanical stability of the membrane could fully meet the service demands for cyclic reuse. As a functional monomer, acrylic acid effectively boosted the material’s adsorption performance toward typical heavy metal ions, including Zn2+, Cu2+ and Pb2+. In simulated acidic wastewater generated from rare earth mining and extraction (pH = 3 and pH = 6.5), the removal efficiency of the as-prepared material for the three heavy metal ions all exceeded 95%. Even after being soaked in strong acid solution at pH 2 for 8 h, its adsorption rate was still maintained at 88.5%. In the cyclic experiment, the adsorption efficiency stayed above 75% after two recycling runs, decreased to roughly 55% in the third cycle, and dropped below 30% at the fourth reuse stage. The introduction of UR imparted remarkable acid-resistant structural stability to the composite material. The membrane structure remained complete without damage after long-term immersion in a pH 2 strong acid environment, and high-efficiency heavy metal removal capability could be guaranteed when the solution pH was not lower than 3. Targeting the practical treatment dilemma of acidic heavy metal-containing wastewater from rare earth exploitation and extraction, this research successfully developed a novel eco-friendly adsorbent featuring superior acid resistance, high adsorption performance and certain recyclability. This newly designed material makes up for the deficiencies in traditional adsorbents represented by activated carbon, including poor heavy metal removal ability in acidic media and secondary pollution risks resulting from disposable use. The research findings can offer a novel technical reference and feasible approach for the purification of acidic rare earth wastewater in practical engineering applications. Full article
(This article belongs to the Section Environmental and Green Processes)
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15 pages, 1214 KB  
Article
Microbial Response to Irrigation with Treated Sewage Water and Sorghum Mulch Cover in a Forage Cactus Agroecosystem
by Isabel Correia Silva Almeida, Danilo José Barros, Michelle Justino Gomes Alves, Belchior Oliveira Trigueiro Silva, Breno Leonan Carvalho Lima, Felipe José Cury Fracetto, Giselle Gomes Monteiro Fracetto, Ademir Oliveira Ferreira, Erika Valente Medeiros and Mario Andrade Lira
AgriEngineering 2026, 8(8), 334; https://doi.org/10.3390/agriengineering8080334 - 13 Aug 2026
Viewed by 209
Abstract
Water scarcity has a significant impact on global agriculture, particularly in semi-arid regions, hindering economic development. The use of recycled urban wastewater in agriculture is a sustainable practice; however, it is essential to assess its impact on soil carbon stocks and microbial activity. [...] Read more.
Water scarcity has a significant impact on global agriculture, particularly in semi-arid regions, hindering economic development. The use of recycled urban wastewater in agriculture is a sustainable practice; however, it is essential to assess its impact on soil carbon stocks and microbial activity. This study hypothesized that the use of wastewater in soil cultivated with forage cactus and amended with 8 or 12 tons of sorghum straw as soil cover could increase carbon stocks, microbial biomass, and microbial activity compared to bare soil, even after only 8 months. The experiment was conducted in a tropical semi-arid region of Brazil, based on a factorial design with different cactus intercropping systems and soil cover treatments under wastewater irrigation. Overall, soil carbon stocks did not increase significantly compared to the control, although they increased by approximately 21% over the study period. However, soil cover increased C-CO2 emissions by 70% after 4 and 8 months. Microbial biomass carbon increased by 65% compared to the baseline (time 0), particularly in treatments with soil cover. Soil cover and consortium under wastewater irrigation improved microbial activity and biomass, even over a short experimental period, indicating a sustainable soil management strategy to enhance soil organic matter quality and microbial properties. Full article
(This article belongs to the Section Sustainable Bioresource and Bioprocess Engineering)
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18 pages, 2153 KB  
Article
Growth Responses of Two Green Manure Crops to Treatments with Non-Sulfur Photosynthesis Bacteria and Wastewater Sludge
by Ping-Yuan Yang, Chun-Han Ko, Bo-Xiang Lee, Chihhao Fan and Tang-Long Shen
Agronomy 2026, 16(16), 1534; https://doi.org/10.3390/agronomy16161534 - 11 Aug 2026
Viewed by 206
Abstract
Wastewater sludge can improve soil fertility and support resource recycling, but potential heavy metal accumulation limits its agricultural application. In this study, we evaluated the effects of anaerobically digested wastewater sludge, applied alone or in combination with the purple non-sulfur bacterium (Rhodopseudomonas [...] Read more.
Wastewater sludge can improve soil fertility and support resource recycling, but potential heavy metal accumulation limits its agricultural application. In this study, we evaluated the effects of anaerobically digested wastewater sludge, applied alone or in combination with the purple non-sulfur bacterium (Rhodopseudomonas palustris), on two green manure crops, Sesbania cannabina and Glycine max. A 90-day pot experiment was conducted with five treatments: control, sludge at 10 and 20 t/ha, and each sludge level combined with R. palustris. Soil physicochemical properties, plant biomass production, and heavy metal concentrations in soil and plant tissues were analyzed. Sludge application increased soil total carbon, total nitrogen, and available phosphorus, while co-application with R. palustris further enhanced phosphorus availability. The greatest biomass production response was observed in G. max under 20 t/ha sludge plus R. palustris, with a 78% increase after 90 days. However, heavy metal concentrations and plant uptake generally increased with sludge dosage, particularly for Ni and Cr. These results indicate that sludge–PNSB application may improve soil fertility and biomass production, but heavy metal risks require careful evaluation. Full article
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24 pages, 600 KB  
Article
Screening-Level Conceptual, Stoichiometric, and Scenario Assessment of Sulfur-Emission Valorization in Coal-Fired Power Plants in Türkiye
by Mustafa Erdemir
Sustainability 2026, 18(15), 7896; https://doi.org/10.3390/su18157896 - 4 Aug 2026
Viewed by 238
Abstract
This study presents a screening-level conceptual, stoichiometric, and scenario assessment of a pathway linking sulfur dioxide (SO2) capture from coal-fired flue gas to sulfuric acid production and the downstream reaction of sulfuric acid with pretreated scrap aluminum. A regenerable sodium sulfite [...] Read more.
This study presents a screening-level conceptual, stoichiometric, and scenario assessment of a pathway linking sulfur dioxide (SO2) capture from coal-fired flue gas to sulfuric acid production and the downstream reaction of sulfuric acid with pretreated scrap aluminum. A regenerable sodium sulfite (Wellman–Lord) capture route, followed by gas polishing and drying, catalytic SO2 oxidation, controlled SO3 absorption, acid conditioning, and an Al–H2SO4 reactor, is used as the reference configuration. The sulfur balance distinguishes sulfur in coal, ash retention, gaseous SOx, SO3/acid mist, absorber inlet and stack slip, captured sulfur, regenerated sulfur, and sulfate purge. Under the central assumptions, 1 t of sulfur in coal yields 0.849 t of recovered sulfur equivalent, 2.599 t of H2SO4, 0.477 t of aluminum feed, 2.419 t of anhydrous-equivalent Al2(SO4)3, 4.240 t of commercial aluminum sulfate on a 17 wt% Al2O3 basis, and 42.4 kg of H2 at 80% aluminum conversion. The upstream base-energy screen is 3.3–7.2 GJth and 0.18–0.45 MWhe per tonne of sulfur in coal. Diluting the acid to the selected 0.5–1.0 M aluminum-reaction window and subsequently producing a 17 wt% Al2O3 product creates a minimum water-removal load of 21.6–47.6 t and a latent-heat floor of approximately 49–108 GJth/t S. Retail prices are replaced by 2024 customs unit values, and internal-acid-production and sulfuric-acid-opportunity-cost boundaries are evaluated separately. In the central opportunity-cost case, the H2 value must reach approximately 6.9 USD/kg merely to balance material values before CAPEX, OPEX, energy, purification, transport, and environmental-compliance costs. The Afşin–Elbistan A case is treated as a full-design-throughput illustration based on an historical 18 Mt/y coal requirement, not as a measured current operating average; coal sulfur is tested over 1.0–2.5 wt%. The aluminum step is restricted to cooled and diluted 0.5–1.0 M H2SO4 at 40–60 °C, and direct H2 production from 96 to 98 wt% acid is not assumed. Plant-specific capacity factor, time-matched coal assays, flue-gas flow, oxygen-corrected stack data, reaction kinetics, gas purity, and product quality remain to be verified. The integrated sustainability screening indicates conditional circular-economy potential rather than a demonstrated sustainability advantage: sulfur recovery must be weighed against energy and water demand, sulfate purge and wastewater, diversion of recyclable aluminum from remelting, hydrogen purification, and market-scale product offtake. The pathway therefore remains a research hypothesis requiring experimental validation, process simulation, techno-economic assessment, comparative life-cycle assessment, safety analysis, and market verification. Full article
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26 pages, 6641 KB  
Article
High-Efficiency Adsorption of PS, PE, and PP Microplastics from Environmental Waters Using a Cross-Linked Chitosan/Graphitic Carbon Nitride/ZIF-67 Nanocomposite
by Amr A. Yakout and Faten M. Ali Zainy
Polymers 2026, 18(15), 1904; https://doi.org/10.3390/polym18151904 - 3 Aug 2026
Viewed by 319
Abstract
Municipal wastewater is a major pathway for the continuous release of microplastics into aquatic environments, making the development of efficient and reusable capture materials essential for advanced water treatment. In this study, a multifunctional ZIF-67/g-C3N4/CS nanocomposite was [...] Read more.
Municipal wastewater is a major pathway for the continuous release of microplastics into aquatic environments, making the development of efficient and reusable capture materials essential for advanced water treatment. In this study, a multifunctional ZIF-67/g-C3N4/CS nanocomposite was designed by integrating cobalt-based zeolitic imidazolate framework ZIF-67 with graphitic carbon nitride (g-C3N4) and a chitosan (CS) biopolymer matrix. The novelty of this material lies in combining the high porosity and tunable surface chemistry of ZIF-67, the π-rich layered structure of g-C3N4, and the hydrophilic, amino-rich chitosan framework into a single adsorptive platform for simultaneous removal of chemically different microplastics. The nanocomposite achieved high removal efficiencies for polystyrene (PS), polypropylene (PP), and polyethylene (PE) microplastics with particle sizes of 20–25 μm, reaching 97.4%, 92.1%, and 90.3%, respectively, at pH 7.6 within 25 min. The higher affinity toward PS is attributed to additional π–π interactions between the aromatic PS chains and the conjugated domains of g-C3N4/ZIF-67, whereas PP and PE removal is mainly governed by hydrophobic adhesion, surface trapping, and interfacial interactions with the chitosan-supported porous framework. The equilibrium data were well described by both Langmuir and Freundlich models, with maximum adsorption capacities of 97.69, 94.86, and 93.67 mg g−1 for PS, PP, and PE, respectively. The nanocomposite retained high recyclability, maintaining 95–97 ± 3.1% removal after five adsorption–desorption cycles. These findings demonstrate that ZIF-67/g-C3N4/CS is a durable and high-performance adsorbent for microplastic remediation, with strong potential for application in municipal wastewater treatment, constructed wetlands, and advanced water-polishing systems. Full article
(This article belongs to the Special Issue Polymer Materials for Ecological and Environmental Applications)
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24 pages, 13567 KB  
Article
Characterization of Glass-Cutting Sludge and Process Wastewater Toward Resource Recovery and Sustainable Water Management
by Paweł Kwaśnicki, Ludmiła Marszałek, Dariusz Augustowski, Katarzyna Grąz, Agnieszka Generowicz and Anna Sykuła
Water 2026, 18(15), 1825; https://doi.org/10.3390/w18151825 - 27 Jul 2026
Viewed by 406
Abstract
This study presents a comprehensive and integrated characterization of solid and liquid residues generated during industrial glass-cutting operations, highlighting the novelty of treating glass-cutting sludge and process wastewater as compositionally linked outputs of the same industrial comminution process. The research examined the morphology, [...] Read more.
This study presents a comprehensive and integrated characterization of solid and liquid residues generated during industrial glass-cutting operations, highlighting the novelty of treating glass-cutting sludge and process wastewater as compositionally linked outputs of the same industrial comminution process. The research examined the morphology, elemental composition, and selected physicochemical properties of sludge and wastewater-derived particulates to assess material-recovery potential and provide a basis for further evaluation of water reuse. Samples were analyzed using particle morphology assessment, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), dynamic light scattering (DLS), and pH measurements. The results showed that the solid fraction consisted predominantly of soda–lime–silica glass constituents, with oxygen, silicon, sodium, calcium, and magnesium as the main components, while potentially problematic contaminants remained at low levels. Although isolated particles enriched in Fe, Cu, Ni, Sn, La, or Ce were detected, their occurrence was limited and did not significantly affect the average particulate composition observed within the SEM-EDS dataset. This is particularly important for coated glass, where functional coatings contribute negligibly to the bulk glass matrix. From a material-recovery perspective, the sludge should be regarded as a promising glass-derived mineral residue requiring further route-specific qualification rather than as waste intended solely for disposal. However, this study does not demonstrate suitability for any specific reuse route, and additional validation is needed regarding compositional consistency, variability, moisture and organic content, leaching behavior, and route-specific acceptance criteria. For process wastewater, contamination was governed mainly by suspended glass-derived solids, indicating that solid–liquid separation is the key treatment step. However, the present dataset is insufficient to confirm the suitability of treated water for direct industrial recirculation, and the results should therefore be interpreted as indicating potential for further evaluation after appropriate clarification. This work establishes an empirical multi-scale characterization framework that links glass-cutting sludge and process wastewater as compositionally related outputs of the same comminution process, thereby supporting circular-economy strategies by jointly informing sludge valorization and water-clarification pathways. Overall, this work establishes a multiscale characterization framework for integrated residue management, jointly supporting sludge valorization and wastewater clarification assessment within a circular-economy perspective. Full article
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28 pages, 18423 KB  
Review
Biodegradable Hydrogels for Pb2+ Removal from Water: Design Strategies, Mechanisms, and Future Perspectives
by Jianhui Guo, Yue Hu, Chang Ma, Wei Zhang, Youming Dong, Yida Niu, Sipei Liu, Yi Zhang and Cheng Li
Gels 2026, 12(8), 667; https://doi.org/10.3390/gels12080667 - 25 Jul 2026
Cited by 3 | Viewed by 249
Abstract
Lead (Pb2+) pollution poses a severe threat to the ecological environment and human health due to its high toxicity, bioaccumulation, and refractory nature. Traditional treatment technologies for lead-contaminated wastewater, such as chemical precipitation, ion exchange, and membrane separation, often face limitations, [...] Read more.
Lead (Pb2+) pollution poses a severe threat to the ecological environment and human health due to its high toxicity, bioaccumulation, and refractory nature. Traditional treatment technologies for lead-contaminated wastewater, such as chemical precipitation, ion exchange, and membrane separation, often face limitations, including secondary pollution, high costs, and high energy consumption. In contrast, adsorption has emerged as a promising alternative technology with advantages such as a simple process, high efficiency at low concentrations, and renewability. Biomass-based hydrogels and their composite systems, as novel green adsorbent materials, combine the abundant functional groups of natural biomass with the structural stability, high porosity, and recoverability of hydrogels through a three-dimensional cross-linked network, offering unique advantages for lead ion adsorption. Depending on their composition, these systems range from fully biodegradable pure biopolymer networks to partly biodegradable or biomass-containing composites incorporating inorganic, carbon-based, or metal–organic framework (MOF) materials. This paper systematically reviews the latest research progress on cellulose, lignin, sodium alginate, chitosan, starch-based hydrogels, and their composite systems for lead (Pb2+) adsorption. First, the structural characteristics, cross-linking mechanisms, and functional modification strategies of various biomass hydrogels are introduced. Then, the adsorption mechanisms of Pb2+, including multiple modes of action such as coordination complexation, ion exchange, electrostatic interaction, and physical adsorption, are systematically analyzed. The adsorption performance of different material systems is compared in detail. The regeneration and recycling performance, as well as the potential practical applications, of the materials are evaluated. On this basis, the main challenges in current research are summarised: balancing adsorption capacity and mechanical strength, achieving selective adsorption in actual wastewater, improving regeneration efficiency, and optimizing costs. In addition, future development directions for biomass hydrogel adsorbent materials are discussed, including the design of multi-functional composite materials, the development of intelligent, responsive hydrogels, engineering-scale-up, and life-cycle assessment. This review aims to provide a theoretical framework and technical roadmap for the rational design of high-performance, sustainable hydrogel adsorbents and to promote their engineering application for the treatment of lead-contaminated wastewater. Full article
(This article belongs to the Special Issue Gel-Related Materials: Challenges and Opportunities (3rd Edition))
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27 pages, 1624 KB  
Review
Chitosan Hydrogels for Antibiotic Remediation and Dye Removal: A Review
by Sai Yin, Wen Yuan, Longmei Zhao, Yida Niu and Jianhui Guo
Gels 2026, 12(8), 658; https://doi.org/10.3390/gels12080658 - 23 Jul 2026
Cited by 3 | Viewed by 503
Abstract
The co-contamination of aquatic environments by antibiotic residues and organic dyes poses a serious threat to ecological security and human health, underscoring the urgent need for high-efficiency, recyclable, and environmentally benign adsorbents. Chitosan, a naturally occurring alkaline polysaccharide rich in reactive functional groups, [...] Read more.
The co-contamination of aquatic environments by antibiotic residues and organic dyes poses a serious threat to ecological security and human health, underscoring the urgent need for high-efficiency, recyclable, and environmentally benign adsorbents. Chitosan, a naturally occurring alkaline polysaccharide rich in reactive functional groups, has attracted considerable attention in water treatment applications. Nevertheless, its practical use is often constrained by intrinsic limitations, including poor stability in acidic media, inadequate mechanical strength, and difficulties in solid–liquid separation. Chitosan-based hydrogels, featuring unique three-dimensional cross-linked networks, high porosity, and strong hydrophilicity, provide efficient mass-transfer pathways for macromolecular contaminants and thus offer a promising strategy to overcome the shortcomings of pristine chitosan. This review comprehensively summarizes recent advances in chitosan-based hydrogel adsorbents, with a focus on elucidating the critical structure–performance relationships that link molecular/structural design to adsorption efficacy. First, fabrication strategies are systematically reviewed, ranging from molecular-level modifications (e.g., grafting, chemical cross-linking, and interpenetrating polymer networks) to macroscopic structural engineering approaches (e.g., mechanically reinforced, magnetic, and stimuli-responsive hydrogels). Subsequently, adsorption behaviors toward representative classes of antibiotics, including tetracyclines, fluoroquinolones, and sulfonamides, are critically examined, with emphasis on the underlying mechanisms such as electrostatic interactions, hydrogen bonding, π–π stacking, and pore-filling effects. In addition, the removal performance of chitosan-based hydrogels for organic dyes with varying charge characteristics is summarized, together with an analysis of how environmental factors (e.g., pH and ionic strength) influence adsorption kinetics and thermodynamics. Finally, key challenges related to mechanical robustness, selective adsorption, and recyclability are discussed, and future perspectives are proposed for the development of multifunctional, synergistic, and intelligent, environmentally responsive chitosan-based hydrogel materials. This review aims to provide systematic insights and guidance for the rational design of advanced hydrogel adsorbents for the treatment of complex wastewater. Full article
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16 pages, 12957 KB  
Article
Cobalt Oxide-Containing Glaze/CaAlg Hydrogel Membrane for Degradation of Orange G via Peroxydisulfate Activation
by Bin Zhang, Minglin Wang, Yawen Liu, Jiabao Cui and Kongyin Zhao
Gels 2026, 12(7), 645; https://doi.org/10.3390/gels12070645 - 19 Jul 2026
Viewed by 322
Abstract
The sustained expansion of printing and dyeing operations has led to the discharge of large volumes of organic wastewater containing dyes. The resulting environmental pollution demands urgent solutions, making the development of efficient and eco-friendly methods for the elimination of dyeing wastewater critically [...] Read more.
The sustained expansion of printing and dyeing operations has led to the discharge of large volumes of organic wastewater containing dyes. The resulting environmental pollution demands urgent solutions, making the development of efficient and eco-friendly methods for the elimination of dyeing wastewater critically important. The combination of alginate hydrogel membranes with advanced oxidation processes (AOPs) for water purification represents an emerging approach in the current field of water treatment. In this study, a calcium alginate membrane was loaded with a glaze containing highly active cobalt oxide to fabricate a glaze-calcium alginate (Glaze-CaAlg) composite membrane. The membrane achieved stable degradation of Orange G dye under optimal conditions, and a series of tests were conducted under varying conditions using pollutant concentrations close to those found in real water bodies. Under optimal conditions (glaze loading = 2.5 mL, PMS = 0.3 mmol/L, cross-flow filtration mode), the membrane achieved a 93.7% degradation efficiency of Orange G (10 ppm) within 45 min, with hydroxyl radicals (·OH, ~79%) identified as the predominant reactive species. The Glaze-CaAlg membrane also exhibited excellent reusability, maintaining a degradation efficiency of over 80% for Orange G across five consecutive cycles. Furthermore, sodium citrate was employed to react with the Glaze-CaAlg membrane, enabling the recovery and secondary application of the glaze. Membranes re-fabricated from the recovered glaze showed mechanical strength and catalytic efficiency comparable to those of the pristine membrane. The Glaze-CaAlg membrane possesses high catalytic activity and good stability. This work offers a sustainable, cost-effective, and recyclable catalytic membrane that converts a traditional ceramic material into an advanced functional material for wastewater remediation, with great potential for practical application in the treatment of refractory organic pollutants. Full article
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33 pages, 17584 KB  
Review
A Bibliometric and Critical Review of Cellulose-Based Aerogels for Wastewater Treatment
by Fengyun Sun, Mingqiao Wang, Shizuo A. Niu, Xiaodong Zhu, Kefa Ren, Yingge Zhang, Yaru Yang and Dong Liu
Gels 2026, 12(7), 643; https://doi.org/10.3390/gels12070643 - 18 Jul 2026
Viewed by 491
Abstract
The treatment of refractory wastewater pollutants requires advanced materials capable of synergistic enrichment and destruction. Cellulose-based aerogels, combining biomass sustainability with a porous structure, are a promising platform, yet a quantitative synthesis of this field’s evolution is lacking. This study presents the first [...] Read more.
The treatment of refractory wastewater pollutants requires advanced materials capable of synergistic enrichment and destruction. Cellulose-based aerogels, combining biomass sustainability with a porous structure, are a promising platform, yet a quantitative synthesis of this field’s evolution is lacking. This study presents the first bibliometric and visual analysis of 463 publications on cellulose-based aerogels for wastewater treatment. The field shows S-shaped growth, evolving from a Nascent phase to Exponential Growth and now entering Maturation. Social network analysis reveals a China-centered but increasingly international collaboration pattern, while institutional productivity remains fragmented into multiple small research teams. The foundation rests on two synergistic pillars: adsorptive sequestration and catalytic degradation, with research evolving from their parallel development to active fusion. Current frontiers focus on sustainable system engineering, emphasizing process integration, material regeneration, and advanced precursors like cellulose nanofiber. This analysis maps the field’s maturation from material exploration toward integrated catalytic system design, providing a foundational reference and clear directives for future research to address integration challenges. In addition to bibliometric mapping, this review critically discusses treatment functions (adsorption, catalytic oxidation, and integrated pathways) and deployment barriers (regeneration, recyclability, and scale-up feasibility), thereby linking knowledge evolution to practical wastewater-treatment translation. While China contributes the largest publication share in the present dataset, the field is supported by increasing participation from multiple countries and regions. Full article
(This article belongs to the Section Gel Analysis and Characterization)
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42 pages, 1599 KB  
Systematic Review
Durability of Geopolymer Concrete Under Chemical Attack: A Review of Acid, Sulfate, Chloride, and Multi-Exposure Resistance
by Mazen J. Al-Kheetan
J. Compos. Sci. 2026, 10(7), 375; https://doi.org/10.3390/jcs10070375 - 17 Jul 2026
Viewed by 484
Abstract
The durability of concrete in chemically aggressive environments remains a major concern for marine structures, wastewater systems, industrial facilities, pavements, and foundations exposed to sulfate-bearing soils. Geopolymer concrete has attracted increasing attention as a lower-carbon alternative to ordinary Portland cement concrete because its [...] Read more.
The durability of concrete in chemically aggressive environments remains a major concern for marine structures, wastewater systems, industrial facilities, pavements, and foundations exposed to sulfate-bearing soils. Geopolymer concrete has attracted increasing attention as a lower-carbon alternative to ordinary Portland cement concrete because its aluminosilicate-rich reaction products, reduced portlandite content, and adjustable precursor–activator chemistry may enhance resistance to various chemical attack mechanisms. However, its durability is strongly governed by mixture composition and exposure regime, and therefore cannot be generalized across all geopolymer systems. This review provides a systematic and critical synthesis of the chemical attack resistance of geopolymer concrete, focusing on acid, sulfate, chloride, marine, wastewater, and combined aggressive exposures. The effects of precursor chemistry, calcium content, activator composition, curing regime, additives, fibers, aggregate type, recycled materials, and environmental coupling are examined in relation to degradation mechanisms and durability indicators. A PRISMA-informed methodology was used to identify, screen, verify, and synthesize primary experimental and modeling studies. The reviewed evidence indicates that low-calcium and well-polymerized geopolymer systems often exhibit favorable sulfate resistance due to the reduced availability of calcium-bearing phases that form expansive products, whereas chloride resistance is primarily governed by pore refinement, chloride transport, binding capacity, pore–solution alkalinity, and reinforcement corrosion behavior. In contrast, acid resistance remains more variable, depending on acid type, pH, exposure duration, solution renewal, calcium content, and the stability of protective silica-rich layers. Additives and alternative aggregates can enhance durability by refining the pore structure, improving the interfacial transition zone, or controlling cracking, but excessive or incompatible dosages may have adverse effects. Overall, geopolymer concrete offers strong potential for chemically aggressive infrastructure when designed through performance-based criteria and validated under realistic multi-exposure conditions. Full article
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40 pages, 2473 KB  
Review
From Vegetable Oil Production to Integrated Biorefineries: Global Trends, By-Product and Side-Stream Valorization, and Green Extraction Technology Deployment
by Ida Zahović, Jelena Parlov Vuković, Lidija Čuček, Aleksandra Petrovič and Marina Tišma
Processes 2026, 14(14), 2330; https://doi.org/10.3390/pr14142330 - 17 Jul 2026
Viewed by 753
Abstract
This review provides a comprehensive assessment of the global production of common edible, specialty, and industrial vegetable oils, with particular emphasis on the generation and valorization of by-products and side-streams within integrated biorefinery frameworks. Attention is given to the main residues generated during [...] Read more.
This review provides a comprehensive assessment of the global production of common edible, specialty, and industrial vegetable oils, with particular emphasis on the generation and valorization of by-products and side-streams within integrated biorefinery frameworks. Attention is given to the main residues generated during oil processing, including oilseed cakes and meals, husks and shells, pomace, refining side-streams, and process wastewaters. The chemical composition of these residues is discussed, highlighting their richness in proteins, dietary fibers, residual lipids, polyphenols, fatty acids, and other bioactive compounds that determine their suitability for downstream valorization. Current management practices are critically assessed, ranging from conventional disposal methods, such as landfilling and incineration, to modern valorization pathways, including anaerobic digestion for biogas production, composting, production of bio-based chemicals, recovery of high-value nutraceuticals, and integration into circular biorefinery models. Special attention is given to green extraction technologies with emphasis on the need for pilot-scale validation, efficient solvent recycling strategies, and integration with existing oil-processing infrastructure. Overall, this review identifies vegetable oil industry by-products and side-streams as technically promising feedstocks for multi-product biorefineries, while emphasizing that industrial implementation will depend on feedstock standardization, solvent recovery and reuse, regulatory acceptance, and integrated techno-economic and life-cycle assessments. Full article
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Review
Vanadyl Porphyrins in Heavy Crude Oils: Extraction, Petroleomics and Catalytic Applications
by Zhannur Myltykbayeva, Anar Seysembekova, Imge Kalkan, Akerke Abylaikhan, Laura Myltykbayeva, Dinara Muktaly and Atıf Koca
Catalysts 2026, 16(7), 649; https://doi.org/10.3390/catal16070649 - 16 Jul 2026
Viewed by 573
Abstract
This review is devoted to the occurrence, extraction, structural characterization and catalytic applications of vanadyl porphyrins present in heavy crude oils and petroleum residues. Vanadyl porphyrins represent the major vanadium-containing compounds in petroleum systems and play a dual role as both catalyst poisons [...] Read more.
This review is devoted to the occurrence, extraction, structural characterization and catalytic applications of vanadyl porphyrins present in heavy crude oils and petroleum residues. Vanadyl porphyrins represent the major vanadium-containing compounds in petroleum systems and play a dual role as both catalyst poisons during refining processes and valuable precursors for functional catalytic materials. Particular attention is devoted to recent advances in extraction technologies, including solvent extraction, ionic liquids, deep eutectic solvents, functionalized adsorbents and chelating agents. Process intensification approaches such as ultrasound- and microwave-assisted extraction, are also discussed as promising strategies for improving extraction efficiency and selectivity. Furthermore, recent developments in petroleum characterization using FTICR-MS, EPR, HYSCORE and LA-ICP-MS techniques are reviewed, providing insights into metalloporphyrin speciation, oxidation states, and distribution within complex petroleum matrices. Beyond their traditional role in catalyst deactivation, vanadyl porphyrins have emerged as attractive precursors for catalytic materials applied in oxidation reactions, photocatalysis, oxidative desulfurization, wastewater treatment and selective organic synthesis. The development of hybrid catalytic systems based on mesoporous silica, graphene oxide, carbon nanotubes, polymer matrices, and metal–organic frameworks has significantly improved catalyst stability, activity and recyclability. Current challenges related to the selective extraction, preservation of metalloporphyrin structure and catalytic performance evaluation are also discussed. Overall, this review provides an integrated perspective on the recovery, characterization and valorization of vanadyl porphyrins for sustainable petroleum upgrading and environmental applications. Full article
(This article belongs to the Section Catalytic Materials)
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