Search Results (464)

Waste lubricating oils (WLOs) represent a major stream of hazardous petroleum-based residues, with global generation exceeding 24 million tons annually. Improper disposal of WLOs poses risks to soil, water, and air quality, while their chemical composition makes them a potential secondary resource within circular economy frameworks. This review summarizes conventional, advanced, and emerging technologies reported for the recycling and valorization of WLOs into high-value petrochemicals and carbon-based materials. Established processes such as acid–clay treatment, solvent extraction, and vacuum distillation are discussed together with more recent approaches, including catalytic upgrading, hydrotreatment, membrane separation, and thermochemical conversion methods such as pyrolysis and catalytic cracking. Reported data on process performance, environmental considerations, techno-economic indicators, and life cycle assessment outcomes are comparatively analyzed to outline current trends, technical challenges, and future development directions in WLO recycling. Particular attention is given to thermochemical pathways capable of generating carbonaceous materials, including carbon black, porous carbons, and functional carbon nanostructures with potential applications in adsorption, catalysis, electrochemical systems, and tribological formulations. Hybrid and integrated process configurations described in the literature are highlighted for their potential to improve recovery efficiency, enhance product quality, and reduce environmental burdens. In addition, recent life cycle assessment (LCA) and techno-economic analysis (TEA) studies are reviewed to provide insight into the environmental and economic implications of advanced re-refining systems. Overall, the reviewed literature indicates that WLO recycling represents not only an important element of sustainable lubricant management but also a promising waste-to-carbon strategy for the production of value-added carbon-based materials and petrochemical products. Full article

The increasing worldwide demand for sustainable energy and effective waste management has heightened interest in solutions. Microbial fuel cells (MFCs) represent a potential category of bioelectrochemical systems that directly transform the chemical energy contained in organic waste into electrical energy via the metabolic processes of electroactive microorganisms. In the last twenty years, significant advancements have occurred in the comprehension of extracellular electron transfer (EET) mechanisms, biofilm formation, microbial community dynamics, electrode material engineering, and reactor design, resulting in marked enhancements in power density and wastewater treatment efficacy. Despite these breakthroughs, the extensive deployment and commercialization of MFC technology are constrained by various hurdles, including inadequate energy recovery, elevated material and fabrication expenses, operational instability, and the intricacies of system scale-up. This cutting-edge analysis offers a thorough evaluation of recent advancements in MFCs and their incorporation with sophisticated technology for waste management and energy generation. Focus is directed towards essential bioelectrochemical principles, microbial and biofilm engineering techniques, sophisticated electrode and membrane materials, reactor designs, and hybrid MFC systems integrated with anaerobic digestion, microbial electrolysis, and advanced oxidation methods. Ultimately, emerging trends, significant knowledge deficiencies, and future research goals are defined to inform the advancement of next-generation MFC systems that support circular economy and net-zero energy initiatives. Full article

Ezrin, expressed by the EZR gene, is a member of the ERM protein family that connects the plasma membrane to the actin cytoskeleton, participating in processes such as cell adhesion, migration, and signaling. However, its role in cardiac morphogenesis remains incompletely understood. In zebrafish (Danio rerio), two ezrin homologs, ezra and ezrb, are present. CRISPR/Cas9 gene editing technology was used to generate ezra knockout lines, and the simultaneous knockdown of ezra and ezrb was induced via morpholino oligonucleotides (MOs). To investigate the molecular mechanisms, transcriptome sequencing and bioinformatic analysis were conducted on 48 h post-fertilization (hpf) ezrin–MO embryos, with subsequent validation using a real-time quantitative polymerase chain reaction (RT-qPCR) and whole-mount in situ hybridization (WISH) experiment. The results showed that ezra^−/− exhibited a compensatory upregulation of ezrb without overt developmental defects, whereas ezrin–MO embryos presented with pericardial edema, reduced cardiac chamber size, and atrioventricular valve malformations at 48 hpf. RNA-seq revealed that myocardial contraction-related genes were significantly dysregulated and apoptotic signaling pathways were activated in ezrin–MO embryos. These findings demonstrate that ezra and ezrb are functionally redundant in cardiac development and that the loss of ezrin function may lead to cardiac developmental defects and impaired myocardial contractility via the activation of apoptotic signaling pathways. Full article

Laser beam welding (LBW) of aluminium busbar-to-terminal connections for electric-vehicle battery packs requires precise in-process monitoring. Membrane-free optical microphones provide a high-bandwidth (DC–MHz) acoustic channel that captures keyhole, melt-pool, and plume dynamics. This study proposes Acoustic Signal Intelligence (ASI), a deep learning framework for LBW state classification from a single optical microphone, evaluated on an open dataset (183 AA1050 welds, $f_s$ = 2.5 MHz) under a five-class taxonomy: lack of fusion, lack of connection, sound, marginal, and piercing. The contributions are: (i) a compact 1-D CNN encoder on a mel-scale STFT spectrogram, reaching the highest macro-F1 (0.72 mean across three-fold replicate-out cross-validation) and 100% piercing recall in every fold—a multi-representation fusion variant adding a wavelet-packet decomposition and a 24-feature library targeting the 8, 63 and 110 kHz keyhole-resonance peaks was evaluated as an ablation arm and did not survive cross-validation, so the proposed model is mel-only; (ii) a systematic benchmark against six classical-ML and four deep learning baselines in which Transformer-hybrid ablations and ACGAN-style augmentation underperform compared to the compact CNN on the 122-sample training set, with the Transformer underperformance confirmed by a 30-configuration grid search over learning rate, weight decay, and dropout (best tuned macro-F1 = 0.441 vs. CNN 0.724); and (iii) a Grad-CAM analysis that recovers the keyhole-resonance bands without prior knowledge. A single optical microphone is thus a viable real-time alternative to multi-sensor stacks for battery-pack laser welding. Full article

Despite its critical role in disease diagnosis as a radiopharmaceutical, Fluorine-18 generates medical wastewater that necessitates efficient treatment, for which membrane adsorption stands out as a potent method, albeit one that demands high-performance membranes with exceptional permeability and adsorption capacity. This study presents a novel cerium-loaded amyloid fibril hybrid membrane designed for efficient removal of fluorine-18 from such wastewater. The membrane is fabricated through a facile process involving oxidation–precipitation of cerium species onto amyloid fibrils, followed by vacuum filtration, with further compositional tuning via incorporation of porous silica or activated carbon dopants. The resulting membrane retains the characteristic amyloid fibril structure and exhibits high water permeability with a flux of up to 803.3 L/(m²·h·bar), superior to most of the other membrane materials. It effectively removes fluoride ions (F⁻) from both low and high-concentration solutions, achieving a removal efficiency of up to 99% and a maximum adsorption capacity of 580 mg/g, outperforming many existing membrane materials. The hybrid membrane also demonstrates notable resistance to ionic interference, enabling selective F⁻ adsorption from solutions containing high concentrations of Cl⁻, NO₃⁻ and SO₄²⁻, with a distribution coefficient (Kd) as high as 4.1 × 10⁴ mL/g; furthermore, it maintains a fluoride removal rate above 51% after ten consecutive adsorption cycles. The membrane retains 51% of its initial fluoride removal efficiency after 10 cycles, indicating potential for repeated use, although further optimization or regeneration strategies would be required to fully restore performance. Mechanistic investigations reveal that F⁻ adsorption occurs mainly through ion exchange with hydroxyl groups on CeO₂. This work introduces a promising novel material with significant potential for the efficient treatment of medical radioactive wastewater containing fluorine-18. Full article

Microplastics have recently emerged as a widespread contaminant in wastewater, posing severe risks to the environment and human health due to their potential bioaccumulation and toxicity. Conventional wastewater treatment processes are generally inadequate for the complete removal of microplastics due to their modest scale. Interest has been garnered from academia and industry regarding their separation from wastewater. This review covers recent advances in the application of membrane processes for the removal of microplastics from wastewater. The principles of membrane separation, removal efficiency, and operational challenges are critically evaluated, along with the potential of the hybrid membrane systems. In the next section, the fouling mechanism induced by microplastics and their interaction with foulants, as well as cleaning and anti-fouling strategies, are discussed. Finally, future perspectives focus on the current unresolved research gaps, including the integration of digital monitoring and artificial intelligence-assisted optimization of membrane technology for microplastic removal. By consolidating current knowledge and identifying pathways for innovation, this review underscores the pivotal role of membranes in mitigating plastic pollution and advancing sustainable wastewater management. Full article

Artesunate (ARU), a key derivative of artemisinin (ART), exhibits excellent water solubility and antimalarial activity due to its incorporation of a succinic acid group. However, the synthesis process of ARU often leaves behind ART with a highly similar structure and properties, making traditional separation methods ineffective for efficient separation. Developing selective separation technologies holds significant importance. Based on previous studies, in work involving the preparation of bidentate MOFs with different ligands, bidentate MOFs containing thiol/amino groups have been found to exhibit outstanding adsorption capacity and selectivity for ARU molecules. Among these, -NH₂ forms hydrogen bonds with -COOH in ARU, while -SH interacts non-specifically with Aru, significantly enhancing the adsorption effect. This study employed a delayed inversion method to prepare a sulfhydryl-amino UiO-66/PVDF hybrid membrane (UiO-66-SH/NH₂/PVDF) by adjusting the composition of the coagulation bath, which was used for efficient separation of ART/ARU. The effects of ethanol ratio in the coagulation bath on membrane structure and performance were systematically investigated. Results showed that increasing the ethanol ratio delays phase transition, promotes MOF material enrichment on membrane pore surfaces, and forms more abundant pore structures. When the ethanol-to-water volume ratio was 1:1, the UiO-66-SH/NH₂/PVDF membrane exhibited optimal pore structure and highest water flux. Static permeation experiments demonstrated that the membrane achieved effective separation of ARU and ART for 8 h, maintaining stable selective adsorption performance after five cycles. This study reveals the critical role of morphology regulation in separating structural analogs, providing new materials and theoretical foundations for efficient separation of artemisinin-based compounds. Full article

The occurrence of organic micropollutants (OMPs) in surface waters poses a significant challenge for advanced water treatment systems. At the same time, the management of membrane retentates containing concentrated contaminants remains a critical limitation of membrane-based technologies. In this study, a hybrid treatment approach integrating nanofiltration (NF) with UV/peracetic acid (UV/PAA) oxidation was investigated to address both OMP removal and retentate treatment. NF effectively removed most of the investigated compounds from surface water but generated a retentate with elevated contaminant concentrations. Subsequent oxidation of the NF retentate using the UV/PAA system resulted in rapid degradation of a wide range of micropollutants. Kinetic analysis revealed pseudo-first-order degradation with rate constants ranging from 0.06 to 1.05 min⁻¹ depending on compound structure. The highest degradation rates were observed for phenolic compounds, while compounds lacking strongly reactive functional groups exhibited slower oxidation kinetics. Increasing the PAA dose significantly enhanced degradation efficiency and enabled near-complete removal of most contaminants. The obtained rate constants fall within the range reported for radical-based advanced oxidation processes. These results demonstrate that coupling NF with UV/PAA oxidation provides an effective strategy for OMPs removal and treatment of membrane concentrates, supporting the development of integrated technologies for advanced water purification. Full article

The rapid development of the aquaculture industry has led to increasing discharges of hypersaline and nutrient-enriched maricultural wastewater. Functional ceramic membranes have garnered significant advantages due to their exceptional chemical stability and high tailorability through surface and interface engineering. This research reviewed recent advances including the functionalization of ceramic membranes and hybrid systems coupled with advanced oxidation processes (AOPs) for enhancing degradations of nutrients and organics in maricultural wastewater treatment. Catalytic ceramic membranes enhanced removal of micropollutants including antibiotics and heavy metals. This review further systematically classified categorization of established functional ceramic membranes and synthesizes cutting-edge modification approaches for membrane fouling mitigation. Finally, this review evaluated the application prospects, challenges for scaled implementation, and proposed future research directions of functional ceramic membranes in the treatment of maricultural wastewater. Full article

Agricultural pesticide wastewater represents a significant environmental and public health challenge, highlighting the need for scalable and resource-efficient treatment strategies. This review adopted a PRISMA-based methodology using the Scopus and Web of Science databases, leading to the analysis of 176 peer-reviewed studies published between 2014 and 2025. The selected literature was critically examined to assess pesticide wastewater treatment technologies, including adsorption, membrane filtration (MF), advanced oxidation processes (AOPs), biological treatments, and hybrid configurations. Particular attention was given to their treatment performance, scalability from farm to district level, resource recovery potential, economic feasibility, and life-cycle assessment (LCA) implications. Among the evaluated systems, hybrid configurations combining biological processes with AOPs or MF generally showed higher removal performance, often achieving more than 80% pesticide residue removal, while offering greater adaptability and compatibility with circular biorefinery frameworks. The review identifies key opportunities for resource recovery, including methane and hydrogen production, nutrient recycling, water reuse, and chemical reclamation, thereby supporting circular bioeconomy objectives. Overall, this review proposes an integrated, multiscale circular biorefinery perspective for sustainable pesticide wastewater management and identifies research priorities for developing resilient, safe, and resource-efficient agricultural water treatment systems. Full article

Population growth, industrialization and climate change have placed increasing stress on natural freshwater reserves, making conventional water sources inadequate. Coupled with rising energy constraints and environmental concerns, interest in desalination technologies that can operate more sustainably and efficiently has intensified. Among the available approaches, membrane desalination has gained particular importance because of its modularity, relatively low energy demand, and compatibility with decentralized water treatment. In parallel, thermoelectric devices have emerged as promising components for hybrid desalination systems due to their ability to convert temperature gradients into electricity or provide localized heating and cooling for process enhancement. This article presents a narrative review of thermoelectric integration in desalination systems, with particular emphasis on membrane desalination and membrane-hybrid water treatment configurations powered by renewable-energy or low-grade heat sources. The review examines the role of thermoelectric devices in relation to key membrane-based and hybrid desalination processes, including reverse osmosis, membrane distillation, electrodialysis, nanofiltration, forward osmosis, and selected hybrid systems. Particular attention is given to system configurations, renewable energy coupling pathways, functional roles of thermoelectric devices, water productivity, module output, desalination efficiency, water quality, and economic performance. The reviewed literature indicates that thermoelectric integration can provide meaningful benefits in hybrid desalination, particularly through improved thermal management, enhanced utilization of low-grade heat, and supplementary energy recovery. These opportunities appear especially relevant for thermally driven membrane systems such as membrane distillation and for membrane-hybrid configurations intended for decentralized or renewable-powered applications. However, the available evidence remains highly heterogeneous, with substantial variation in system scale, operating conditions, reporting metrics, and cost assumptions, which limits direct cross-study comparison and broad generalization of performance claims. This review highlights the technical challenges, reporting inconsistencies, and research gaps that currently constrain the practical development of thermoelectric-assisted membrane desalination and outlines future directions for membrane-aligned hybrid desalination research. Full article

The complete removal of persistent aromatic organic pollutants from aqueous environments demands the development of sustainable and highly efficient filtration materials. In this study, novel bio-sourced mixed-matrix membranes (MMMs) were successfully fabricated by incorporating the highly porous metal–organic framework MIL-68(Al) into a biodegradable polylactic acid (PLA) matrix via a solvent-induced phase inversion method. The integration of MIL-68(Al) nanoparticles significantly tailored the membrane’s morphological structure, endowing the hybrid membranes with enhanced surface hydrophilicity (water contact angle reduced from 90.3° to 72.7°) and superior permeability. The pure water flux reached an optimal value of 42.2 L m⁻² h⁻¹ at a 15 wt.% MOF loading. Crucially, the hybrid membranes exhibited exceptionally high adsorptive removal performance for p-nitrophenol (PNP) and methylene blue (MB). Driven by the abundant accessible active sites of the MOF filler, the MIL-20/PLA membrane achieved a maximum equilibrium adsorption capacity of 121.03 μg/cm² (36.90 mg/g) for PNP, representing a remarkable 25.7-fold enhancement over the pristine PLA membrane. Kinetic analyses confirmed that the adsorption process is strictly governed by pseudo-second-order kinetics, indicating a chemisorption mechanism dominated by hydrogen bonding and π–π stacking interactions. Furthermore, the optimized membranes demonstrated outstanding dynamic filtration efficiencies (>80%) and robust regenerability over multiple continuous operating cycles. This work not only highlights the synergistic interfacial effects between MOFs and biodegradable polymers but also provides a highly effective, eco-friendly, and sustainable membrane platform for the advanced remediation of organic-contaminated wastewater. Full article

This study investigates the integration of nanofiltration (NF) and membrane distillation (MD) for the selective separation and recovery of critical metals from effluents generated by supercritical water oxidation (SCWO) of lithium-ion batteries. Beyond resource recovery, the proposed hybrid system addresses the urgent environmental challenge associated with highly contaminated battery recycling effluents, which pose severe risks to aquatic ecosystems if improperly managed. NF90 and NF270 membranes exhibited complementary behavior: NF90 achieved high rejection of Co, Ni, and Mn (>70%) with a minimum lithium rejection of 30%, whereas NF270 showed lower rejection of divalent metals (40%) and lower lithium rejection (<20% at pH = 7), along with a higher permeability. Subsequent MD enabled water recovery while concentrating lithium in the MD concentrate (brine), maintaining near-complete rejection of transition metals (>90%) and reducing the effluent conductivity by more than 85%. Surface characterization (SEM–EDS, AFM, BET, and contact angle) revealed fouling mechanisms and wettability loss, highlighting operational stability limitations. In this hybrid approach, nanofiltration enables the selective separation of lithium from transition metals, while membrane distillation promotes water recovery and concentrates lithium into a recoverable brine, with fouling and wetting defining the operational boundaries of the process. Overall, the results demonstrate that coupling SCWO with NF–MD represents a viable and scalable pathway for simultaneous effluent detoxification and lithium recovery, contributing to circular economy strategies and the sustainable management of battery-recycling wastewater. Full article

Biogas produced from the anaerobic digestion of organic matter holds much promise as a renewable energy source for decentralized systems. However, raw biogas contains substantial volumes of carbon dioxide, hydrogen sulfide, water vapor, and other trace impurities. These impurities can reduce the calorific value of biogas and limit its direct use for household energy needs. Purifying biogas to high-grade biomethane (≥95%) is therefore important to improve methane (CH₄) content and combustion characteristics. This is a guarantee of its safe utilization in domestic appliances, including cooking, heating, lighting, and electricity generation. This article reviews and evaluates novel approaches for upgrading raw biogas into high-purity biomethane that can offset natural gas in domestic applications. It further examines recent developments in conventional and innovative upgrading technologies such as water scrubbing, chemical scrubbing, pressure swing adsorption, membrane separation, cryogenic separation, and biological upgrading. Particular emphasis is placed on low-cost and small-scale solutions suitable for off-grid or mini-grid rural energy systems. Moreover, the role of process optimization, intelligent monitoring, and data-driven control methods in increasing CH₄ recovery and process efficiency is discussed. Despite their relatively high capital costs and energy needs, conventional technologies such as water scrubbing, pressure swing adsorption, and membrane technology continue to dominate biogas purification systems. The findings show that coupling advanced separation technologies, including cryogenic separation, biological upgrading, and hybrid technologies, with optimized process control can significantly improve CH₄ purity, save energy use, and enhance the overall consistency of biogas purification systems. These innovative strategies have strong potential to promote the full-scale adoption of biomethane as a clean, sustainable, and affordable energy source for decentralized applications, particularly in the developing world. Full article

Domestic wastewater is a chemically complex and highly variable mixture of pollutants generated by everyday household activities, yet its contribution to environmental contamination is still frequently underestimated and only 56% of wastewater worldwide is being treated. This review provides a structured and quantitative assessment of major domestic wastewater pollutant groups, their principal exposure pathways, and current and emerging treatment technologies. Beyond a conventional narrative synthesis, the review derives per capita annual emission estimates from published data and uses these to compare pollutant groups by mass flow and environmental relevance. The analysis shows that high-volume household inputs, particularly sodium chloride from domestic water softening, toilet paper, personal-care products, detergents, and cleaning agents, can contribute substantially to overall pollutant loads, whereas lower-mass contaminants such as pharmaceuticals, antibiotics, PFAS, heavy metals, and microplastics remain critical because of their persistence, biological activity, and incomplete removal during treatment. The review further highlights that conventional wastewater treatment systems are often poorly equipped to remove many of these emerging contaminants effectively, especially under decentralised or only partially advanced treatment conditions. Advanced and hybrid technologies, including membrane bioreactors, nanofiltration, reverse osmosis, adsorption, photocatalysis, and electrochemical processes, offer clear potential, but their broader implementation remains constrained by cost, energy demand, fouling, and concentrate management. Overall, the added value of this review lies in linking mass-based pollutant prioritisation with treatment performance, thereby providing a more systematic basis for identifying dominant household emission pathways and for guiding targeted mitigation and technology selection in future wastewater management. Full article