As the global freshwater crisis intensifies, desalination has emerged as a reliable method for water supply worldwide. However, the high energy consumption and operating costs associated with conventional steam-driven seawater desalination remain significant challenges. This study proposes a low-temperature multi-effect distillation (LT-MED) model driven by waste heat to replace conventional steam and reduce the cost of distillation. A case study was conducted on the 15,000 m³/day Hengli Petrochemical hybrid system in Dalian, China, which integrates distillation desalination with hot-water flashing. The thermodynamic model of the hybrid system, based on energy and mass balance equations, demonstrates that a seven-effect evaporator setup offers the most cost-effective and energy-efficient solution. The study explores four methods to enhance the Gain Output Ratio (GOR) and identifies optimal parameters and configurations for improved overall system performance. The findings provide valuable insights for designing innovative hybrid distillation systems powered by low-grade waste heat.
Bioleaching is regarded as an environmentally sustainable process for recycling spent lithium-ion batteries (LIBs). However, at high pulp densities, its application becomes challenging due to reduced microbial activity caused by the toxic metal components in the LIB black mass. Accordingly, the applicability of bioleaching under high pulp density conditions requires systematic evaluation. In this study, Acidithiobacillus ferriphilus 9-P1 was utilized, and leaching parameters, including inoculation rate, temperature, agitation speed, pulp density, and initial Fe2+ concentration, were tested in both 2 L and 10 L laboratory-scale reactors. Among the bioleaching factors, the bioleaching efficiency was enhanced by increasing the inoculation ratio to 50% and the iron concentration from 8.8 to 33 g/L. Elevating the temperature to 37.5°C significantly improved the leaching efficiencies to 99.2% for Li, 96.1% for Al, 96.8% for Mn, 98.7% for Co, 98.6% for Ni, and 95.8% for Cu within 168 h. Furthermore, at the 10 L reactor scale, leaching efficiencies exceeding 90% for Li, Al, Mn, Co, and Ni, and 81.6% for Cu were achieved within 168 h. These results demonstrate that bioleaching can serve as a practical and environmentally friendly alternative to traditional LIB recycling processes even under high pulp density conditions.
Currently, manganese-based catalysts suffer from insufficient low-temperature activity and a tendency to chlorine poisoning-induced deactivation during the catalytic combustion of chlorobenzene. This study successfully developed Nb-Ca/MnO2 catalysts, with the Nb(2)-Ca(2)/MnO2 catalyst exhibiting superior performance: A T90 of 340°C for CB conversion at 15,000 mL·g⁻¹·h⁻¹, over 85% conversion retention during a 30-hour test, and a significant reduction in polychlorinated by-products. Catalyst characterization results indicated that Nb existed in the form of Nb2O5. A small amount of Nb substantially increased the Mn3⁺/Mn4⁺ ratio and markedly raised the proportion of surface adsorbed oxygen. Furthermore, Nb loading enhanced the low-temperature redox capability of the catalyst. The introduction of Nb significantly altered the distribution of acidic sites, promoted the desorption of chlorine species, and effectively suppressed the formation of polychlorinated by-products. In situ DRIFTS results revealed the generation of abundant bidentate carbonates and maleates during the reaction, along with a significant reduction in chlorine species on the spent catalyst. The Nb-Ca/MnO2 catalyst exhibited advantages in both catalytic activity and resistance to chlorine poisoning.
Recently, there have been increasing challenges in handling surplus biomass such as barley straw, and technologies that utilize these materials to create high value-added resources, such as electrode materials, are gaining considerable attention. In this study, a barley straw biochar-based activated carbon was synthesized from an agricultural by-product and evaluated for membrane capacitive deionization (MCDI). The electrochemical properties and hardness removal performance of the fabricated electrode were systematically investigated and compared with those of six commercial activated carbon electrodes. The biochar-based electrode exhibited a morphology comparable to commercial electrodes and showed typical electric double-layer capacitive behavior. The MCDI system achieved a deionization capacity of approximately 14 mg/g and a deionization rate of 0.035 mg/g/s. Although the deionization rate was slightly lower than that of some commercial electrodes, the biochar-based electrode demonstrated comparable deionization capacity and energy consumption (approximately 0.98 Wh/g-CaCl2). In addition, excellent cycling stability was observed, with 94.6% of the initial charge capacity retained after 180 cycles and Coulombic efficiency exceeding 99%. These results demonstrate that barley straw biochar-based activated carbon is an alternative to commercial activated carbon electrodes for CDI-based hardness control.
Perfluorooctanoic acid (PFOA), a representative "forever chemical," poses significant threats to ecosystems and human health due to its persistence and bioaccumulation. While molecularly imprinted polymers (MIPs) offer selectivity for PFOA removal, their practical application is often hindered by low adsorption capacity and difficulties in separation. To address these limitations, this study developed a novel magnetic chitosan-based molecularly imprinted polymer (MMIP) via a surface molecular imprinting strategy. The synthesized MMIP utilized magnetic chitosan as a support and employed a dual-functional monomer system (methacrylic acid and chitosan) to enhance adsorption sites. Characterization confirmed the material's superparamagnetism, uniform porous structure, and crystalline stability. The adsorption process followed a Pseudo-second-order kinetic model and the Langmuir isotherm model, suggesting monolayer chemisorption as the primary adsorption mechanism with the synergy of electrostatic interactions and hydrogen bonding. The MMIP exhibited a high saturation adsorption capacity of 51.28 mg g-1 and a significant imprinting factor of 2.65, demonstrating excellent selectivity for PFOA even in the presence of structural analogs. Furthermore, the material retained over 90% of its adsorption capacity after five cycles, proving its robust reusability. This work highlights the potential of the designed MMIP as a highly efficient, selective, and easily separable adsorbent for the remediation of PFOA-contaminated water.
This study introduces a deep learning-based soft-sensor framework integrating ensemble empirical mode decomposition, average Hurst exponent analysis, and multi-scale prediction for PM2.5 early warning. The proposed methodology proceeds in three stages: first, ensemble empirical mode decomposition is employed to decompose raw PM2.5 time series into multiple intrinsic mode functions representing distinct frequency components; second, average Hurst exponent is to compute each timescale to determine the most suitable optimal prediction model for subsequent forecasting tasks; finally, PM2.5 concentration predictions are generated by aggregating forecasts across all decomposed timescales. Experimental results demonstrate that the hybrid model outperforms reference models in extracting discriminative features and modelling complex temporal dependencies within PM2.5 datasets. Specifically, its coefficient of determination exceeds those of the comparative models―convolutional neural network, gated recurrent unit and its versions implemented with empirical mode decomposition and ensemble empirical mode decomposition methods―by 33.8%, 20.29%, 10.67%, and 1.12%, respectively, highlighting the effectiveness of multi-scale feature fusion in enhancing prediction accuracy. With the more effective and accurate soft-sensor model proposed, the research offers a novel perspective on bridging process safety engineering with environmental sustainability, demonstrate how data-driven intelligence can address health-protective problems better and provides a feasible suggestion for resource-efficient infrastructure operations.
Water scarcity and stringent environmental regulations are emerging challenges in pharmaceutical manufacturing, necessitating sustainable wastewater management solutions. Zero Liquid Discharge systems offer complete water recovery; however conventional ZLD processes often energy-intensive and operationally complex. This review critically examines the evolution of ZLD systems in the pharmaceutical sectors with a focus on recent advancements in process optimization and digital integration. The adoption of Industry 4.0 technologies including of Internet of Things and Artificial Intelligence has demonstrated significant potential to enhance system performance through real time monitoring, predictive maintenance and adaptive process control. Evidences from pilot scale studies and industrial case reports indicates AI-assisted optimization can reduced energy consumption by 20-30% improve water recovery efficiency beyond 90-95% and lower operational costs. Emerging membrane-based technologies, like forward osmosis and membrane distillation show improved energy efficiency compared to traditional thermal methods. Although life cycle assessments highlight energy use as major environmental concern, optimized systems can reduced overall impacts. Challenges remain, including high capital cost, system complexity, data dependency and integration constraints. A multi-criteria assessment framework is proposed to support informed decision making. Overall, digitally enabled ZLD systems offer strong potential for sustainable pharmaceutical wastewater management, through further scalable and region-specific validation is required.
Water pollution caused by synthetic dyes from textile, pharmaceutical, paper, and tannery industries remains a major environmental challenge due to persistence, toxicity, and complex chemical structures of these compounds. It is estimated that approximately 700,000 tons of dyes are produced annually worldwide, with 10-15% being discharged into aquatic environments as industrial effluents. Unlike previous reviews that mainly emphasize adsorption capacity, this review addresses critical practical gaps by evaluating economic viability, regeneration capability, scalability, and technology readiness of cost-effective adsorbents for dye remediation. Recent advances in low-cost adsorbents, including biochar, industrial by-products, agricultural wastes, activated carbons, and nanomaterials are systematically analyzed regarding synthesis methods, surface modification approaches, and performance under realistic conditions. Comparative assessment reveals that biochar-based adsorbents typically achieve 85–95% dye removal at costs 60–70% lower than commercial activated carbon, while nanomaterial-based systems demonstrate superior removal efficiencies (>98%) but encounter scalability, cost, and recovery challenges. By integrating performance metrics with economic and practical considerations, this review offers guidance for developing sustainable and commercially viable adsorption-based technologies for industrial dye wastewater treatment.
This study investigated the potential of brewer’s spent grain (BSG) as a sustainable carbon source for polyhydroxyalkanoates (PHA) production through acidogenic fermentation. The effect of inoculum-to-substrate ratio (ISR) on volatile fatty acid (VFA) production was systematically evaluated using anaerobic digestion sludge at ISR values of 0.5, 1.5, 2.5, and 3.5. ISR 0.5 achieved the highest VFA yield of 1.05 mg COD/mg VS, whereas higher ISR conditions resulted in limited accumulation due to enhanced microbial consumption and methane production, with cumulative methane yields of 486–523 mL CH4/g COD at ISR 1.5–3.5 compared to 142 mL CH4/g COD at ISR 0.5. Substrate degradation analysis revealed that carbohydrate-driven acidogenesis dominated the early phase, followed by protein-associated fermentation. Enrichment of PHA-accumulating microorganisms in a sequencing batch reactor (SBR) increased PHA content to approximately 30 wt%. Batch accumulation tests demonstrated that both BSG-derived VFA and acetate supported PHA production, with acetate achieving a higher final PHA content (56.7 wt%) compared to BSG-derived VFA (45.4 wt%). Kinetic analysis using the Richards model showed negligible lag time for BSG-derived VFA, while acetate exhibited a lag phase but higher accumulation rates. These results demonstrate that ISR is a key parameter controlling carbon partitioning and VFA production.
The catalytic performance of biochar for peroxymonosulfate (PMS) activation strongly depends on its modification strategy, yet the relationship between structural regulation and activation mechanism remains insufficiently clarified. In this study, corn cob-derived biochar was synergistically modified using potassium oxalate activation and urea-assisted nitrogen doping to enhance surface defects and electronic properties for PMS activation toward phenol removal. The modified catalyst (K-NBC) exhibited a significantly increased specific surface area, approximately 36 times higher than that of pristine biochar. The effects of initial pH, PMS concentration, catalyst dosage, and phenol concentration were systematically evaluated. Radical quenching experiments, electron paramagnetic resonance (EPR), and electrochemical analyses suggested that free radicals, likely including O2•-, and non-radical electron-transfer pathways jointly contributed to phenol removal. Density functional theory (DFT) calculations and GC–MS/MS analysis were further employed to propose possible transformation pathways, and the ecotoxicity of detected intermediates was predicted using ECOSAR. This study provides insights into the rational design of defect-engineered and nitrogen-functionalized biochar catalysts for PMS-based advanced oxidation processes in water treatment.
The objective for this research was to utilize hybrid amine doped with Fe2O3 nano-particles for absorbing CO2. The nano-fluid was examined for optimizing the desorption rate as well as the regeneration percent of the solvent by applying the Taguchi design methodology. Optimization on desorption was made by a blend of monoethanolamine (MEA)/triethanolamine (TEA) as well as introducing iron oxide nano-particles in order to increase mass as well as heat transfer. The effects on four vital parameters, that is, stirrer speed, nanoparticle concentration, nanoparticle size, as well as temperature, were analyzed systematically by a Taguchi L60 orthogonal array consisting of 60 experimental runs. The investigation showed that greater stirring rates as well as nano-particle diameters significantly enhanced CO2 desorption rates, as well as that the temperature became the dominant factor. Increasing the concentration of nano-particles beyond 0.1 vol.% offered diminishing returns on investment. ANOVA testing discovered that stirrer speed produced the highest significance followed by nano-particle diameter as well as temperature. In general, we found that optimizable nano-fluid compositions can significantly enhance the effectiveness of CO2 desorption as well as show great promise as a viable approach toward more efficient carbon capture systems.
Aerobic granular sludge (AGS) slowly forms granules during the treatment of low-carbon/nitrogen ratio (low C/N ratio) petrochemical wastewater. This study investigated adding powdered activated carbon (PAC) to improve granulation during the treatment of low C/N ratio petrochemical wastewater. The optimal dosage for practical applications was also investigated. First, the activated sludge system (R1), a system with added PAC (R2), and a system with added Fe2+ (R3) were investigated. The results showed that by day 60, R2 had achieved complete granulation, while R1 and R3 had not. The control group without PAC (R1) and the groups supplemented with PAC (R2, R3, R4, and R5, with 0.5, 1, 2, and 3 g/L PAC, respectively) were studied. The results showed that on day 16, the average particle size of the groups with PAC exceeded 200 μm, while the group without PAC was only 99.9 μm. Moreover, R5 produced the largest particles and achieved COD and NH4+-N removal efficiencies of 86.6% and 98%, respectively. This study provides a practical reference for the application of PAC for treating low C/N ratio petrochemical wastewater.
Biogas purification is essential for mitigating corrosion and environmental risks associated with acidic impurity gases. In this study, yeast–alginate hydrogel composite biosorbents prepared by Ca²⁺ gelation followed by Fe³⁺ secondary crosslinking were investigated for selective acidic-gas removal in a fixed-bed column system. Response surface methodology (RSM) was employed to optimize key operating parameters governing the biosorption process. The Fe³⁺-crosslinked yeast–alginate composites exhibited markedly enhanced removal of H2S and CO2 compared with non-Fe³⁺ controls, while CH4 loss remained consistently below 5%, indicating preferential removal of acidic gases over methane. Structural and physicochemical characterizations confirmed the formation of a stable mesoporous network with effective Fe³⁺ incorporation, and biological assays demonstrated preserved yeast viability after adsorption. Overall, these results highlight the potential of Fe³⁺-crosslinked yeast–alginate composite biosorbents as a selective and sustainable material for biogas purification and provide a foundation for further evaluation under continuous-flow conditions.
The contamination of soils by pesticides and microplastics adversely affects soil structure, microbial communities, and soil biota, highlighting the need for environmentally sustainable remediation approaches. Biochar has received growing attention as a promising amendment for soil remediation due to its porous structure and high specific surface area. The remediation performance of biochar varies widely depending on physicochemical properties, which are influenced by several factors including feedstock type, pyrolysis conditions, and surface modification strategies. This review summarizes recent research trends in biochar-based remediation of pesticides and microplastics, identifies key factors governing remediation performance, and discusses limitations associated with current studies highlighting knowledge gaps limiting practical application. Although existing studies indicate promising remediation potential, most studies have focused on short-term batch adsorption or column experiments that do not fully reflect the complexity of co-contaminated soils and long-term stability under field conditions. Therefore, to advance biochar toward practical implementation, further efforts should include optimization of surface modification techniques, clarification of their effects on biochar properties, validation through field-scale studies, evaluation of microplastics across diverse polymer types and particle-size ranges, and quantitative assessment of interactions among co-contaminants. These efforts will be essential for developing biochar into a sustainable and effective remediation technology for soils.
Indonesia has abundant natural resources, including high-quality Fe-based minerals that can be used as adsorbents and photocatalysts. This study aims to use Fe-based photocatalyst in Hutumuri’s soil (IRSH) incorporated with zinc oxide (ZnO) to enhance the adsorption-photocatalytic ability towards methylene blue (MB) in solution. Simple impregnation of ZnO onto IRSH retains its structural and textural features, suggesting good stability. The band gap of ZnO/IRSH composites increases from 2.29 eV to 2.51 eV as ZnO loading increased, surpassing the band gap of IRSH. This band gap is within the visible-light range, indicating that ZnO/IRSH composites can absorb visible-light. These features enhance photocatalytic activity to 96%, which is higher than IRSH (75%) and ZnO (52%). Additionally, the addition of ZnO to IRSH decreases PL intensity, indicating decreased charge-carrier recombination rate. As a result, the photocatalytic activity of ZnO/IRSH is enhanced by efficient charge-carrier separation and transfer. Based on response surface methodology, the highest MB photodegradation by ZnO/IRSH is achieved at pH 9 and a dosage of 35 mg, consistent with the parameter effects. Finally, the photodegradation mechanism is proposed based on LC-MS analysis. This study provides a sustainable approach by utilizing natural-based photocatalyst for wastewater treatment.
This study conducted a systematic bibliometric analysis and comprehensive literature review of 906 publications from 2016 to 2025. The review categorizes AI applications into three core pillars: industrial flue gas treatment, air quality management, and CO2 capture. This analysis identifies a significant paradigm shift from traditional statistical monitoring toward sophisticated AI-driven surrogate modeling, generative material discovery. In industrial flue gas treatment domain, AI-based surrogates have enhanced multi-pollutant prediction accuracy (e.g., R2>0.94). In outdoor and indoor air quality management, hybrid AI and Large Language Model (LLM) frameworks have improved spatiotemporal forecasting and monitoring reliability by up to 94.46% alarm judgement accuracy under data-constrained conditions. Furthermore, in CO2 capture, the integration of generative AI and agentic AI systems has revolutionized adsorbent discovery, enabling rapid inverse design of metal-organic framework (MOF). Despite these advancements, the air pollution domain-AI faces challenges, including data scarcity in transient process, limited model interpretability, and the gap between computational design and experimental validation. Future research should prioritize Physics-Informed Neural Networks for high-fidelity modeling, Reinforcement Learning for adaptive control, and Agentic AI for End-to-End workflow. These emerging AI technologies are essential for developing scalable, high-precision air pollution management systems capable of meeting future environmental challenges.
The practical deployment of cuprous oxide (Cu2O) in photocatalytic remediation is severely restricted by its intrinsic photocorrosion and fast charge recombination. To address these issues, a novel water-mediated in situ one-pot hydrothermal-calcination strategy is developed to fabricate a robust ternary In2O3/Cu/Cu2O heterojunction. Water acts as a kinetic regulator to precisely control Cu reduction and phase evolution, enabling intimate interfacial contact among In2O3, metallic Cu, and Cu2O. The optimized composite shows outstanding photocatalytic activity for sulfamethoxazole (SMX) degradation under simulated sunlight, with a rate constant of 0.0181 min-1, 36.2 times higher than pure Cu2O. It also exhibits excellent photostability, retaining 94.4% activity after five cycles with negligible Cu leaching. Mechanistic studies reveal a Cu-mediated all-solid-state Z-scheme charge transfer pathway. The Cu bridge serves as an electron relay, extracting photogenerated electrons from the Cu2O conduction band to recombine with holes in the In2O3 valence band. This suppresses Cu2O self-reduction while maintaining high redox potential for reactive radicals (∙O2⁻, h+) generation. This work provides a green, facile route to design stable multi-component Z-scheme photocatalysts for efficient removal of refractory pharmaceutical pollutants.
Capacitive deionization (CDI) is a promising desalination technology but is often limited by the low ion removal capacity of carbon-based electrodes. In this study, a hybrid capacitive deionization (HCDI) system employing an asymmetric silver/activated carbon (Ag/AC) electrode configuration was investigated under constant-current operation and compared with a conventional membrane capacitive deionization (MCDI) system. Desalination performance was evaluated using CDI Ragone plot analysis, while galvanostatic charge–discharge measurements were used to examine the potential evolution of individual electrodes. The results show that the Faradaic Ag/AgCl reaction stabilizes the cell voltage and expands the usable potential window of the activated carbon electrode. As a result, the HCDI system consistently outperformed MCDI, achieving a maximum salt adsorption capacity of 36.5 mg g⁻¹ in a 10 mM NaCl solution, more than twice that of MCDI (17.0 mg g⁻¹), along with a faster ion removal rate. These findings demonstrate that integrating Faradaic electrodes effectively overcomes the intrinsic capacity limitations of conventional CDI systems.
Heavy metals and microplastics (MPs) are persistent co-contaminants in agricultural soils, posing serious threats to agricultural sustainability. Biochar (BC) amendments have demonstrated potential for soil remediation and health improvement, but their efficacy in soils co-contaminated with heavy metals and MPs remains unclear. A factorial pot experiment evaluated four biochars derived from Solidago canadensis L. (SBU-BC), corn straw (CoB), rice straw (RoB), and peach twigs (PoB) in soils contaminated with cadmium (Cd) and polyethylene microplastics (PE-MPs), applied individually or together. After a growth cycle of Pak choi (Brassica rapa chinensis L.), soil properties and plant physiological indices (e.g., antioxidant enzymes) were assessed. Co-contamination of Cd and MPs synergistically exacerbated oxidative stress in plants, elevating leaf superoxide dismutase activity by 32% relative to single-stress conditions. Among the BC treatments, SBU-BC proved most effective, alleviating stress, increasing Pak choi biomass by 15.5%, reducing Cd accumulation in shoots and roots by nearly 20%, and enhancing soil nutrient availability (e.g., cation exchange capacity, nitrate). These findings suggest that SBU-BC may contribute to better soil conditions and increased crop resilience under Cd and MPs co-contaminated soils, however, further field-scale trials are required to validate its effectiveness under real agricultural conditions.
The increasing use of short-chain per- and polyfluoroalkyl substances (PFASs) and PFASs alternatives has led the widespread environmental distribution and new pollution profiles, posing new challenges for the efficient removal of PFASs. This study systematically compared the occurrence, removal, and sludge enrichment characteristics of PFASs in two parallel wastewater treatment processes (activated sludge and biofilm). A total of 21 PFASs were detected in the influent, with short-chain PFASs accounting for 60.8%. The total PFASs removal efficiency of biofilm process (58.9%) was higher than that of activated sludge process (53.6%), especially under the high proportion of short-chain PFASs in the influent. Among the 15 PFASs detected in sludge, biofilm process sludge exhibited significantly higher total PFASs concentration and a more complex composition, with notably increased proportion of short-chain PFASs (particularly PFBS). In contrast, the sludge of activated sludge process was dominated by long-chain PFASs with negligible short-chain components. Biofilm processes exhibit superior removal performance for wastewater containing a high proportion of short-chain PFASs and their alternatives. The study provides comprehensive insights into the effective removal of PFASs in different wastewater treatment configurations, offering valuable guidance for PFASs control in wastewater treatment plants.
