Search Results (782)

The synergistic effect of using D2EHPA and TOPO together to enhance the extraction of samarium(III) from aqueous media via emulsion liquid membrane (ELM) technology was explored. D2EHPA in binary mixtures with TBP and in ternary mixtures with TOPO and TBP was also tested. Among the tested extractants, a binary mixture of 0.1% (w/w) D2EHPA and 0.025% (w/w) TOPO achieved 100% samarium(III) extraction at a low loading. This mixture outperformed D2EHPA-TBP and other systems because D2EHPA strongly binds to Sm(III) ions, while TOPO increases the solubility and transport efficiency of metal complexes. Additionally, process factors that optimize performance and minimize emulsion breakage were examined. Key insights for successfully implementing the process include the following: 5 min emulsification with 0.75% Span 80 in kerosene at pH 6.7 (natural), 250 rpm stirring, a 1:1 internal/membrane phase volume ratio, a 20:200 treatment ratio, and a 0.2 N HNO₃ stripping agent. These insights produced stable, fine droplets, enabling complete recovery and rapid carrier regeneration without emulsion breakdown. Extraction kinetics accelerate with temperature up to 35 °C but declined above this limit due to emulsion rupture. The activation energy was calculated to be 33.13 kJ/mol using pseudo-first-order rate constants. This suggests that the process is diffusion-controlled rather than chemically controlled. Performance decreases with Sm(III) feed concentrations greater than 200 mg/L and in high-salt matrices (Na₂SO₄ > NaCl > KNO₃). Integrating these parameters yields a scalable, low-loading ELM framework capable of achieving complete Sm(III) separation with minimal breakage. Full article

Lithium has emerged as a critical element in contemporary society. It has been classified as an indispensable feedstock in the manufacture of lithium-ion batteries for electric mobility, portable electronics, and stationary energy storage systems, which are essential for the integration of intermittent renewable energy sources. This metal also has other industrial applications and is projected to support future developments in semiconductor and aerospace technology. However, the exponential growth in global Li demand driven by energy transition and technological innovation requires a resilient and sustainable supply chain where both technological and environmental challenges should be addressed. This review discusses and analyzes some of current challenges associated with the Li supply chain given a particular emphasis on its separation methods. First, statistics of the Li market and its applications are provided, including the main sources from which to recover Li and the environmental impact associated with conventional Li extraction techniques from mineral ores and salar brines. Different separation methods (e.g., solvent extraction, adsorption, ion exchange, membrane technology) to recover Li from different sources are reviewed. Recent advances and developments in these separation strategies are described, including a brief analysis of their main limitations and capabilities. The importance and potential of recycling strategies for end-of-life batteries and industrial residues are also highlighted. A perspective on the gaps to be resolved with the aim of consolidating the Li supply chain to support the energy transition agenda is provided in this review. Full article

Membrane technology is widely used in gas separation processes due to its small footprint, high energy efficiency, and favorable economic viability. The current membrane market predominantly relies on polymer membranes, among which polyimide (PI) membranes stand out as highly promising materials due to their superior gas separation performance coupled with exceptional thermal and chemical stability. However, traditional polyimide membranes suffer from low gas permeability and insufficient plasticization resistance, hindering their broader industrial application. In order to meet the demands of more stringent application fields, it is crucial to further improve their gas performance and anti-plasticization to enhance their cost-effectiveness. Consequently, it is essential to modify traditional polyimides and formulate membrane fabrication strategies to solve these problems. This review introduces the monomer structures and synthesis approaches of polyimides, including solution-based and solid-state thermal condensation. Then, we propose representative preparation methods of polyimide-based membranes. Additionally, modification strategies, including thermal rearrangement, cross-linking, and physical blending, are summarized, which address the critical issues in contemporary polyimide-based gas separation membranes. Finally, this review critically discusses the current challenges and prospects for developing polyimide membranes for gas separation. Full article

Oil-contaminated wastewater presents a significant environmental challenge, necessitating the development of efficient and adaptable treatment technologies. In this study, a pH-responsive chitosan-coated polyethersulfone (Ch/PES) membrane was developed and systematically evaluated for oil/water separation performance under varying pH conditions. PES was chosen as the base membrane material due to its excellent chemical resistance and mechanical durability, while Ch, a biodegradable and environmentally friendly biopolymer with pH-sensitive properties, was applied as a functional surface coating. The Ch/PES membrane was successfully fabricated and characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy, confirming successful surface modification and structural integrity. Additional analyses—including underwater oil contact angle measurements, porosity assessment, and cross-sectional morphological evaluation—demonstrated the membrane’s dynamic pH-responsive wettability and pore size modulation. Oil emulsion separation experiments, conducted using sodium dodecyl sulfate-stabilized emulsions, revealed that the Ch/PES membrane achieved oil removal efficiencies exceeding 97% under acidic conditions. This enhancement was attributed to increased hydrophilicity and reduced effective pore size resulting from chitosan swelling. In contrast, under alkaline conditions, the membrane exhibited greater oleophilicity and maintained a relatively stable pore structure, leading to a reduced separation efficiency of 83.8%. Compared to the unmodified PES membrane, the Ch/PES membrane demonstrated significantly improved responsiveness and adaptability to changes in pH, underscoring its potential as a versatile platform for treating oil-contaminated wastewater of varying chemistries. These findings suggest that the Ch/PES membrane offers a promising, sustainable, and efficient solution for advanced oil/water separation applications. Full article

A comprehensive literature review highlights how the nature of active metals, support materials, promoters, and synthesis methods influences catalytic performance, with particular attention to ruthenium-based catalysts as the current benchmark. Kinetic models are presented to describe the reaction pathway and predict catalyst behavior. Various reactor configurations, including fixed-bed, membrane, catalytic membrane, perovskite-based, and microreactors, are evaluated in terms of their suitability for ammonia decomposition. While ruthenium remains the benchmark catalyst, alternative transition metals such as iron, nickel, and cobalt have also been investigated, although they typically require higher operating temperatures (≥500 °C) to achieve comparable conversion levels. At the industrial scale, catalyst development must balance performance with cost. Inexpensive and scalable materials (e.g., MgO, Al₂O₃, CaO, K, Na) and simple preparation techniques (e.g., wet impregnation, incipient wetness) may offer lower performance than more advanced systems but are often favored for practical implementation. From a reactor engineering standpoint, membrane reactors emerge as the most promising technology for combining catalytic reaction and product separation in a single unit operation. This review provides a critical overview of current advances in ammonia decomposition for hydrogen production, offering insights into both catalytic materials and reactor design strategies for sustainable energy applications. Full article

Industrial processes like farming, food processing, petroleum refinery, and leather manufacturing produce a lot of high-salinity wastewater. This wastewater presents serious environmental risks, such as soil degradation, eutrophication, and water salinization, if it is released without adequate treatment. The sources and features of high-salinity wastewater are outlined in this review, along with the main methods for removing organic pollutants, such as physicochemical, biological, and combined treatment approaches. Membrane separation, coagulation–flocculation, and advanced oxidation processes are the primary physicochemical techniques. Anaerobic and aerobic technologies are the two categories into which biological treatments fall. Physicochemical–biological combinations and the fusion of several physicochemical techniques are examples of integrated technologies. In order to achieve sustainable and effective treatment and resource recovery of high-salinity wastewater, this review compares the effectiveness and drawbacks of each method and recommends that future research concentrate on the development of salt-tolerant catalysts, anti-fouling membrane materials, halophilic microbial consortia, and optimized hybrid treatment systems. Full article

Polymer inclusion membranes (PIMs) have undergone substantial advancements in their selectivity and efficiency, driven by their increasing deployment in separation processes, environmental remediation, and sensing applications. This review presents recent progress in the development of PIMs, focusing on strategies to enhance ion and molecule selectivity through the incorporation of novel carriers, including ionic liquids and task-specific extractants, as well as through polymer functionalization techniques. Improvements in mechanical and chemical stability, achieved via the utilization of high-performance polymers such as polyvinylidene fluoride (PVDF) and polyether ether ketone (PEEK), as well as cross-linking approaches, are critically analyzed. The expanded application of PIMs in the removal of heavy metals, organic micropollutants, and gas separation, particularly for carbon dioxide capture, is discussed with an emphasis on efficiency and operational robustness. The integration of PIMs with electrochemical and optical transduction platforms for sensor development is also reviewed, highlighting enhancements in sensitivity, selectivity, and response time. Furthermore, emerging trends towards the fabrication of sustainable PIMs using biodegradable polymers and green solvents are evaluated. Advances in scalable manufacturing techniques, including phase inversion and electrospinning, are addressed, outlining pathways for the industrial translation of PIM technologies. The review concludes by identifying current limitations and proposing future research directions necessary to fully exploit the potential of PIMs in industrial and environmental sectors. Full article

Membrane separation technology can be operated in moderate conditions with low energy consumption and has been widely explored and increasingly applied in the water treatment, food, chemical, and pharmaceutical industries. As an upgraded counterpart, stimulus-responsive membranes can respond to external stimuli (such as light, temperature, pH, electric field, magnetic field, etc.) and actively modulate their own physical and chemical properties, thus showing self-adaptive ability and improved performance. This review provides a comprehensive overview of the recent advancements in the design principles, fabrication methods, and applications of these stimulus-responsive membranes. The challenges and future directions in this field are also prospectively discussed, highlighting the potential for further innovation and industrial applications of stimulus-responsive membranes. Full article

Cryogenic upgrading represents a promising route for the production of high-purity biomethane, aligning with current decarbonization goals and the increasing demand for renewable gases. This review provides a critical assessment of cryogenic technologies applied to biogas purification, focusing on process fundamentals, technological configurations, energy and separation performance, and their industrial integration potential. The analysis covers standalone cryogenic systems as well as hybrid configurations combining cryogenic separation with membrane or chemical pretreatment to enhance efficiency and reduce operating costs. A comparative evaluation of key performance indicators—including methane recovery, specific energy demand, product purity, and technology readiness level—is presented, along with a discussion of representative industrial applications. In addition, recent techno-economic studies are examined to contextualize cryogenic upgrading within the broader landscape of CO₂ separation technologies. Environmental trade-offs, investment thresholds, and sensitivity to gas prices and CO₂ taxation are also discussed. The review identifies existing technical and economic barriers, outlines research and innovation priorities, and highlights the relevance of process integration with natural gas networks. Overall, cryogenic upgrading is confirmed as a technically viable and environmentally competitive solution for biomethane production, particularly in contexts requiring liquefied biomethane or CO₂ recovery. Strategic deployment and regulatory support will be key to accelerating its industrial adoption. The objectives of this review have been met by consolidating the current state of knowledge and identifying specific gaps that warrant further investigation. Future work is expected to address these gaps through targeted experimental studies and technology demonstrations. Full article

Hollow fiber membranes have revolutionized various gas separation processes due to their unique characteristics such as high surface area, small system footprint, and high energy efficiency compared to flat sheet or spiral wound membranes. This review analyzes the current state of the art of hollow fiber technology, exploring its diverse applications across various fields. Over the past ten years, research has primarily focused on improving hollow fiber fabrication techniques, including phase inversion, electrospinning, and 3D printing, highlighting their impact on membrane performance and selectivity. Furthermore, we discuss the challenges and future perspectives of hollow fiber technology, focusing on the development of novel materials and surface modifications to enhance membrane durability and efficiency. Finally, this review provides an overview of current gas separation techniques, spanning both conventional and next-generation methods, based on the foreseen field of exploitation of hollow fiber membranes. Full article

Produced water, a byproduct of oil and gas extraction, poses significant environmental challenges due to its complex composition and high salinity. Conventional treatment technologies often struggle to achieve efficient contaminant removal while maintaining long-term operational stability. Membrane-based separation processes, particularly forward osmosis (FO), offer a promising alternative due to their low hydraulic pressure requirements, high selectivity, and ability to mitigate fouling and scaling effects. This study fabricated and evaluated a novel dual-layer zwitterion-modified electrospun nanofibrous membrane for enhanced produced water (PW) treatment. The dual-layer design consists of a highly porous electrospun nanofibrous support layer for improved permeability and mechanical strength, coupled with a zwitterionic-modified selective layer to enhance antifouling properties and selective contaminant rejection. The zwitterionic surface modification imparts superior hydration capacity, reducing organic and biological fouling while improving water transport efficiency. The membranes are characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), contact angle and tensile strength measurements, and nuclear magnetic resonance (NMR) spectroscopy to assess their morphological, structural, and chemical properties. The performance evaluations demonstrated significantly higher water flux (up to 16.05 L m⁻² h⁻¹ for SPW (synthetic produced water) and 6.00 L m⁻² h⁻¹ for PW using NaBr) and excellent solid rejection (up to 96.02% for SPW and 88.90% for PW), reduced concentration polarization, and superior antifouling performance compared to conventional FO membranes. Experimental results from bench-scale trials demonstrate that this advanced membrane technology offers enhanced water recovery and contaminant removal efficiency, making it a viable solution for industrial-scale PW treatment and reuse. The findings underscore the potential of next-generation dual-layer FO membranes in promoting sustainable water resource management within the oil and gas sector while minimizing environmental impact. Full article

Bionic synthesis technology has made significant breakthroughs in porous functional materials by replicating and optimizing biological structures. For instance, biomimetic titanium dioxide-coated carbon multilayer materials, prepared via biological templating, exhibit a hierarchical structure, abundant nanopores, and synergistic effects. Bionic mineralization further enhances microcapsules by forming a secondary inorganic wall, granting them superior impermeability, high elastic modulus, and hardness. Through techniques like molecular self-assembly, electrospinning, and pressure-driven fusion, researchers have successfully fabricated centimeter-scale artificial lamellar bones without synthetic polymers. In environmental applications, electrospun membranes inspired by lotus leaves and bird bones achieve 99.94% separation efficiency for n-hexane–water mixtures, retaining nearly 99% efficiency after 20 cycles. For energy applications, an all-ceramic silica nanofiber aerogel with a bionic blind bristle structure demonstrates ultralow thermal conductivity (0.0232–0.0643 W·m⁻¹·K⁻¹) across a broad temperature range (−50 to 800 °C). This review highlights the preparation methods and recent advances in biomimetic porous materials for practical applications. Full article

The increasing use of pharmaceutically active compounds (PhACs), endocrine-disrupting compounds (EDCs), and personal care products (PCPs) has led to the widespread presence of organic micropollutants (OMPs) in aquatic environments, posing a significant global challenge for environmental conservation. In recent years, advanced materials-based nanofiltration (NF) technologies have emerged as a promising solution for water and wastewater treatment. This review begins by examining the sources of OMPs, as well as the risk of OMPs. Subsequently, the key criteria of NF membranes for OMPs are discussed, with a focus on the roles of pore size, charge property, molecular interaction, and hydrophilicity in the separation performance. Against that background, this review summarizes and analyzes recent advancements in materials such as metal organic frameworks (MOFs), covalent organic frameworks (COFs), graphene oxide (GO), MXenes, hybrid materials, and environmentally friendly materials. It highlights the porous nature and structural diversity of organic framework materials, the advantage of inorganic layered materials in forming controllable nanochannels through stacking, the synergistic effects of hybrid materials, and the importance of green materials. Finally, the challenges related to the performance optimization, scalable fabrication, environmental sustainability, and complex separation of advanced materials-based membranes for OMP removal are discussed, along with future research directions and potential breakthroughs. Full article

Minimizing carbon dioxide emissions is crucial due to the generation of energy from fossil fuels. The significance of carbon capture and storage (CCS) technology, which is highly successful in mitigating carbon emissions, has increased. On the other hand, hydrogen is an important energy carrier for storing and transporting energy, and technologies that rely on hydrogen have become increasingly promising as the world moves toward a more environmentally friendly approach. Nevertheless, the integration of CCS technologies into power production processes is a significant challenge, requiring the enhancement of the combined power generation–CCS process. In recent years, there has been a growing interest in process intensification (PI), which aims to create smaller, cleaner, and more energy efficient processes. The goal of this research is to demonstrate the process intensification potential and to model and simulate a hybrid integrated–intensified adsorptive-membrane reactor process for simultaneous carbon capture and hydrogen production. A comprehensive, multi-scale, multi-phase, dynamic, computational fluid dynamics (CFD)-based process model is constructed, which quantifies the various underlying complex physicochemical phenomena occurring at the pellet and reactor levels. Model simulations are then performed to investigate the impact of dimensionless variables on overall system performance and gain a better understanding of this cyclic reaction/separation process. The results indicate that the hybrid system shows a steady-state cyclic behavior to ensure flexible operating time. A sustainability evaluation was conducted to illustrate the sustainability improvement in the proposed process compared to the traditional design. The results indicate that the integrated–intensified adsorptive-membrane reactor technology enhances sustainability by 35% to 138% for the chosen 21 indicators. The average enhancement in sustainability is almost 57%, signifying that the sustainability evaluation reveals significant benefits of the integrated–intensified adsorptive-membrane reactor process compared to HTSR + LTSR. Full article

The discharge of oily wastewater threatens the ecosystem and human health, and the efficient treatment of oily wastewater is confronted with problems of high mass transfer resistance at the oil-water-solid multiphase interface, significant light shielding effect, and easy deactivation of photocatalysts. Although traditional physical separation methods avoid secondary pollution by chemicals and can effectively separate floating oil and dispersed oil, they are ineffective in removing emulsified oil with small particle sizes. To address these complex challenges, photocatalytic technology and photocatalysis-based improved technologies have emerged, offering significant application prospects in degrading organic pollutants in oily wastewater as an environmentally friendly oxidation technology. In this paper, the degradation mechanism, kinetic mechanism, and limitations of conventional photocatalysis technology are briefly discussed. Subsequently, the surface interface modulation functions of metal doping and heterojunction energy band engineering, along with their applications in enhancing the light absorption range and carrier separation efficiency, are reviewed. Focus on typical studies on the separation and degradation of aqueous and oily phases using photocatalytic membrane technology, and illustrate the advantages and mechanisms of photocatalysts loaded on the membranes. Finally, other new approaches and converging technologies in the field are outlined, and the challenges and prospects for the future treatment of oily wastewater are presented. Full article