Search Results (965)

Microbial fuel cells (MFCs) offer a promising pathway for treating wastewater while simultaneously generating electricity; however, they remain largely pilot-scale technology due to persistent limitations, such as low power density. Microalgae can act as in situ oxygen suppliers in the cathode chamber of dual chamber MFCs, enhancing electricity generation while facilitating nutrient removal. This study compares the performance of cathodic microalgae in MFCs utilizing either a cation exchange membrane (CEM) or an anion exchange membrane (AEM). Raw municipal wastewater collected from the preliminary tank was used as the anodic substrate, while pre-cultivated Chlorella vulgaris (optical density ≈ 0.42) was introduced into the cathode chambers. The performance of both configurations was constantly monitored through various analytical methods. The AEM-based MFC produced significantly higher and more stable voltages (avg. 0.05 volts; peak ≈ 0.11 volts) and achieved a 0.95 mW/m² peak power density, compared to the CEM-based MFC, which produced lower voltages (avg. 0.01 volts; peak ≈ 0.06 volts) and achieved a 0.25 mW/m² peak power density. No significant differences in nutrient removal rates were found among the membranes. Findings demonstrate the superiority of AEM configurations for microalgae-assisted MFCs, establishing a more viable framework for potential large-scale wastewater treatment applications. Full article

The proton (H⁺) and vanadium ion (Vⁿ⁺) selectivity of proton-conductive membrane is one of the key components for vanadium redox flow batteries (VRFBs). In this work, a hydrophobic side chain was designed to accelerate proton conduction with high selectivity of H⁺ and Vⁿ⁺ for the VRFB membrane. The grafting of hydrophobic butyl side chains into the membrane (PBIOSO₃-But) induced the formation of a high microphase separation capacity to form large and connected ion conductive channels with low ion exchange capacity (IEC). As a result, the PBIOSO₃-But membrane with low IEC of 1.26 mmol g⁻¹ shows area resistance of 0.19 Ω cm² as well as vanadium permeability of 3.2 × 10⁻⁹ cm² s⁻¹, leading to a high H⁺/Vⁿ⁺ selectivity of 2.51 × 10¹⁰ mS s cm⁻³ (higher than Nafion 212, 4.62 × 10⁸ mS s cm⁻³). Notwithstanding its low ion-exchange capacity, this membrane demonstrates H⁺/Vⁿ⁺ selectivity surpassing that of recently reported microphase separation membranes. Compared to the Nafion 212 membrane (74.3% EE; 0.81% per cycle), the PBIOSO₃-But membrane exhibited superior VRFB performance, achieving an energy efficiency of 83.2% at 200 mA cm⁻² and a low retention rate of 0.22% per cycle. These values compare favorably with those of recently reported membranes. Full article

This study investigates the enhancement of hydrogen production efficiency in water electrolysis through the application of external magnetic fields. A series of controlled experiments were conducted using four distinct electrode materials—stainless steel (SS), low-carbon steel (LCS), titanium (Ti), and platinum-plated titanium (Ti/Pt)—to identify the optimal configuration for maximizing gas output. The research evaluated the influence of electrolyte concentration (KOH), current density, and magnetic field intensity ranging from 0 to 1800 G. Our findings indicate that the application of a 200 G magnetic field leads to a notable 6% increase in the rate of gas production compared to non-magnetized conditions. Specifically, a magnetic field oriented parallel to the electrode plates outperformed a perpendicular orientation by approximately 5%, a phenomenon attributed to the Lorentz force facilitating ionic mass transfer and gas bubble detachment. Furthermore, the integration of ion-exchange and proton-exchange membranes (MC-3470 and N-117) effectively isolated the anodic and cathodic products, elevating hydrogen purity from 67.4% to approaching 100% without compromising electrolysis efficiency. These results demonstrate that the strategic coupling of moderate magnetic fields with optimized electrode configurations provides a promising pathway for improving the efficiency and cleanliness of hydrogen production, which is essential for its role as a sustainable energy carrier. Full article

To meet aviation decarbonization goals, novel electric energy storage systems are required. A promising approach combines a Li-ion battery with a hydrogen proton exchange membrane fuel cell system (PEMFCS) into an electrochemical energy storage and conversion (EC-ESC) system. Proper power management ensures efficiency, reliability and durability. The study investigates EC-ESC performance for regional hybrid electric aircraft under varying degrees of hybridization. By systematically adjusting the power split between the battery and FCS, we quantify its impacts on system sizing, energy efficiency and battery degradation. The results show that a well-balanced power distribution enhances overall efficiency and energy density while extending system lifetime. Full article

Perfluorosulfonic acid (PFSA) membranes, exemplified by Nafion, suffer dehydration-induced degradation at elevated temperatures, although modifications enhance their conductivity and performance. Sulfonated aromatic polymers (SAPs) exhibit weaker phase separation, yielding narrow, tortuous ion channels and lower conductivity than their PFSA membrane counterparts at equivalent ion exchange capacity; however, excessive sulfonation causes swelling and mechanical instability, offset by cost advantages. Phosphoric acid-doped polybenzimidazole (PBI) offers superior thermal stability and high conductivity, with recent advances in polybenzimidazole derivatives and composites driving medium-to-high temperature proton-exchange membrane fuel cell innovation. This review summarizes progress in three major medium-to-high temperature proton-exchange membrane fuel cell categories—perfluorosulfonic acid, sulfonated polymers, and PBI-based membranes—while addressing challenges and future goals for enhanced performance. Full article

Redox-flow batteries are a promising emerging technology for large-scale storage of renewable energy. However, existing ion-exchange membranes used for separating electrolytes are expensive and often ineffective at preventing crossover of redox-active species, leading to a decrease in battery capacity over time. Herein, we introduce a new class of proton-conducting membranes formed by depositing highly alkylated waxy hydrophobic salts on porous polypropylene supports and demonstrate that they form self-assembled nanostructures which exclusively conduct protons via a unique mechanism of action. These new “ionowax” membranes display comparable proton conductivities to existing commercially available functionalized porous polymer membranes but are cheaper and easier to fabricate. We anticipate that these new membranes will facilitate future development of cheaper and/or longer-lasting aqueous redox-flow batteries. Full article

This study presents an optimized and comparative investigation of four intelligent energy management strategies—Proportional–Integral–Derivative (PID), Fuzzy Logic Control (FLC), Equivalent Consumption Minimization Strategy (ECMS), and Artificial Neural Network (ANN)—applied to a photovoltaic–fuel cell–battery hybrid electric vehicle (PV–FC–HEV). A high-fidelity MATLAB/Simulink model integrates a 6 kW proton-exchange membrane fuel cell (PEMFC), a 500 W photovoltaic subsystem with MPPT, and a lithium-ion battery (LiB) pack. While 1000 W/m² represents Standard Test Conditions (STC), the level of 400 W/m² was specifically selected to simulate average cloudy conditions common in urban driving environments, rather than standard NOCT (800 W/m²), to test the EMS’s robustness under significantly reduced PV support and stressed battery conditions (initial SOC = 30%). While surface contamination and the resulting performance degradation significantly impact real-world results, this study assumes a clean surface to establish an idealized performance baseline for the control algorithms. However, the authors acknowledge that contaminant accumulation is a key factor; future work will incorporate a degradation factor (e.g., a 10–15% efficiency penalty) to evaluate the reliability of these EMS strategies under actual operating conditions. ECMS achieved the lowest hydrogen consumption, saving up to 10 L compared with PID, while ANN maintained the most stable state of charge (SOC > 80%), minimizing deep discharge cycles and improving operational stability. FLC provided balanced operation under fluctuating irradiance. Overall, ANN offered the most harmonized energy flow and dynamic stability, whereas ECMS maximized fuel economy. The findings provide practical guidance for designing sustainable and intelligent control systems in next-generation hybrid electric vehicles. Full article

Sulfide-alkaline wastewater (SAW) from petrochemical plants, particularly from pyrolysis and hydrotreating units, presents a significant environmental challenge due to its high toxicity, extreme alkalinity (pH > 12), and high concentrations of sulfides and organic pollutants. Traditional treatment methods like acid neutralization or air oxidation are often inefficient, generate secondary waste, or fail to recover valuable components. This study investigates the effectiveness of a novel electrochemical system for the simultaneous treatment of SAW and recovery of valuable products. A lab-scale four-chamber electrodialyzer, equipped with cation-exchange membranes and nickel bipolar electrodes, was designed and tested using real industrial wastewater. The wastewater was characterized by a pH of 13.06, chemical oxygen demand of 12,600 mg/L, and a sulfide content of approximately 5000 mg/L. The process leverages anodic oxidation to convert sulfide ions into elemental sulfur, while sodium cations migrate through cation-exchange membranes to the cathodic compartments. There, water reduction generates high-purity hydrogen (≥99.9%) and a concentrated, purified sodium hydroxide solution. The results demonstrate the ineffectiveness of electrodialysis with anion-exchange membranes due to rapid membrane degradation. In contrast, the proposed electrodialyzer with bipolar electrodes achieved excellent performance: a caustic soda solution with a concentration of 2.3–2.5% was recovered with a current efficiency of 83–85%, containing only trace amounts of sulfides (0.0052%) and organic impurities (0.053%). The process completely removed the original sulfide alkalinity. The study confirms the chemical and mechanical stability of the cation-exchange membranes under harsh SAW conditions. The proposed technology offers a path towards a closed-loop system in refineries by enabling the reuse of recovered caustic, utilization of hydrogen, and potential recovery of sulfur, aligning with the principles of green chemistry and circular economy. Full article

Lithium-ion batteries (LIBs) have become the prominent energy storage technology because of their high specific energy, longer lifespan, and excellent efficiency. Traditional lithium extraction processes are energy intensive and time-consuming. Direct lithium extraction (DLE) methods provide a more sustainable and efficient alternative. This review offers a comprehensive overview of lithium-ion battery resources and direct lithium extraction methods. The detailed discussion of the DLE methods, which include adsorption, ion exchange, solvent extraction, membranes separation, and electro-chemical systems is presented. A comprehensive analysis of the recent technological advances of the direct lithium extraction processes in terms of technology readiness levels, and commercial potential is reported. The advantages and the technical challenges of the DLE methods are also reported. Finally, the review outlines the artificial intelligence outlook of the DLE processes. The review aims to provide deeper insights into the limitations and the opportunities of DLE methods towards crucial future research efforts for lithium-ion batteries advancements. Full article

The large-scale generation of industrial waste salts (IWSs) across sectors such as coal chemical, pesticide, pharmaceutical, and dye manufacturing has raised increasing environmental and regulatory concerns. These IWSs often exhibit complex physicochemical profiles—featuring high concentrations of inorganic salts, persistent organic pollutants, and trace heavy metals—that pose significant challenges for both safe disposal and resource recovery. This review provides a comprehensive and pollutant-oriented overview of industrial waste salts, focusing on their sector-specific characteristics, dominant contaminant types, and tailored treatment strategies. Removal pathways for organic matter (e.g., thermal decomposition, advanced oxidation) and inorganic impurities (e.g., precipitation, ion exchange) are systematically analyzed, followed by technical pathways for salt separation based on crystallization and membrane processes. Resource utilization routes for major salt components, particularly NaCl and Na₂SO₄, are critically assessed in terms of technical feasibility, impurity tolerance, and end-use compatibility. The emergence of reclaimed salt quality standards and sector-specific impurity thresholds reflects a paradigm shift from purity-based to performance-based reuse evaluation. Finally, the review highlights future priorities including adaptive impurity control, downstream-specific salt grading, and enforceable regulatory frameworks to ensure the safe, scalable, and circular deployment of reclaimed salts in industrial systems. This study supports the coordinated advancement of control technologies and reuse standards, enabling the transformation of waste salts from environmental liabilities to secondary resources. Full article

This study elucidates the mechanism enabling the low-voltage electrolysis of black liquor (BL) for integrated resource recovery. The process simultaneously generates protons at the anode via the oxidation of organics (OOR), which occurs at a lower potential than the oxygen evolution reaction (OER), and induces lignin precipitation. Concurrently, hydrogen and hydroxide ions are produced at the cathode through the hydrogen evolution reaction (HER). Driven by the electric field, sodium ions migrate from the anode to the cathode chamber, combining with hydroxide ions to form sodium hydroxide, thereby achieving the synchronous production of acid, alkali, hydrogen, and modified lignin in a single process. Using a platinum electrode, we conducted a mechanistic investigation through linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and detailed product analysis. The results show that overall efficiency is controlled by competition at the anode between OOR and OER, which directly determines proton yield. A critical trade-off exists between anodic proton generation and cathodic alkali recovery, driven by the competitive migration of protons and sodium ions across the cation-exchange membrane. The proton yield was highly dependent on the initial BL composition, with a characteristic peak observed under specific conditions. Conversely, the sodium hydroxide recovery rate was maximized when the anolyte pH remained high, minimizing competitive proton migration. This work provides fundamental insights into the interfacial mechanisms of BL electrocatalytic, establishing it as a versatile electrochemical biorefinery platform for simultaneous proton and alkali production from a renewable waste stream, beyond its role as a hydrogen source and lignin recovery. Full article

This study presents a novel, integrated membrane–resin hybrid platform for the high-efficiency purification of N-acetylneuraminic acid (sialic acid, NANA) from complex microbial fermentation broths. By synergistically combining four sequential stages—ceramic microfiltration (50 nm), ultrafiltration (3 kDa), nanofiltration (150 Da), and dual-resin purification (macroporous adsorption + cation-exchange)—the process achieves stepwise removal of cells, proteins, pigments, monovalent salts, and divalent metal ions without using organic solvents or high-salt buffers. Critically, each stage demonstrates high target recovery: 76.2% (CM), 67.3% (UF), and 77.5% (NF), with near-quantitative retention (>95%) during resin treatment due to NANA’s low hydrophobicity and electrostatic repulsion at pH 6.8. Following optimised acidification crystallisation (acetic acid dosage = 3 × concentrate volume; sialic acid concentrate concentration = 333.49 g/L), the final product reaches 97.9% purity with a crystalline yield of 78.6%. This scalable, green purification strategy eliminates major bottlenecks in downstream processing and enables industrial-scale production of pharmaceutical-grade sialic acid, with broad applicability to other high-value acidic biomolecules. Full article

Naturally Occurring Radioactive Materials (NORMs) in industrial wastewater present significant environmental and public health challenges due to their persistence and radiotoxic effects. This comprehensive review analyzes 108 peer-reviewed publications from 2014 to 2025 on NORM treatment technologies for industrial wastewater. While previous reviews have focused on individual treatment methods or laboratory-scale studies, this work provides comparative performance analysis across multiple technologies under realistic industrial conditions, including high-salinity environments and competing ions. We emphasize membrane filtration, electrocoagulation (EC), ion exchange, and advanced oxidation processes, evaluating both their economic feasibility and environmental sustainability for practical industrial implementation. The review discusses the advantages and limitations of existing techniques, highlighting the need for integrated strategies that combine physical, chemical, and biological processes for enhanced remediation. Hybrid systems combining multiple technologies outperform individual approaches by 15–25% in removal efficiency. These advances are critical for ensuring safe water reuse and protecting water resources from radioactive contamination. Additionally, regulatory frameworks governing NORM management are examined, underscoring the importance of standardized disposal and treatment protocols. The review concludes by identifying research gaps and future directions. Priority areas include developing standardized treatment protocols and strengthening academia–industry collaboration to achieve scalable solutions aligned with UN Sustainable Development Goal 6. Full article

Acidic polysaccharides, valued for their outstanding bioactivity and physicochemical properties, represent a promising strategy for metabolic disease intervention. In this study, three acidic polysaccharide fractions (BRP-1, BRP-2, and BRP-3) were isolated from Brassica rapa L. using membrane filtration and ion-exchange chromatography. BRP-3, notable for its high galacturonic acid content (76.64%), was further purified to yield the homogeneous fraction BRP-3-1 (Mw = 22.3 kDa). Combining GC-MS, FTIR, and NMR analyses, we report for the first time the detailed structure of BRP-3-1—a heteropolysaccharide composed of rhamnose (1.687%), galacturonic acid (75.584%), galactose (14.452%), and arabinose (8.277%)—with a backbone composed with T-α-L-Araf-(1 → 5)-α-L- Araf -(1 → 4)-α-D-GalpA-(1 → 4)-α-D-2-O- GalpA Me-(1 → 4)-α-D-GalpA-(1 → 4)-α-D-GalpA-(1 → 3)-Galp-(1 → 4)-α-D-GalpA, and T-Rhap, T-Galp as well as T-GalpA for branched chain and terminals. In HepG2 insulin-resistant cells, BRP-3-1 demonstrated potent dual regulation of glucose and lipid metabolism—enhancing glucose consumption, lowering total cholesterol, and significantly reducing triglyceride levels in the high-dose group (800 μg/mL), outperforming BRP-2. This work systematically defines the structure of a highly bioactive acidic polysaccharide from B. rapa L. and confirms its metabolic regulatory effects, offering a strong scientific foundation for its application in functional foods and as an adjuvant therapeutic for metabolic disorders. Full article