Journal of Applied Membrane Science & Technology
Journal of Applied Membrane Science & Technology (AMST) provides an international forum for publications of original research, interpretative reviews, book reviews and discussion of new developments in membrane science and technology. Papers which describe the novel theory of membrane science and technology and its applications to practice as well as reports of carefully executed experimental work which is soundly interpreted are most welcome. The journal was launched by Universiti Teknologi Malaysia (UTM) in 2005 and is currently managed by the Advanced Technology Membrane Research Centre (AMTEC). Since its inception, >200 articles have been published as of 2023. The scope of the papers submitted to JAMST include but not limited to the following: Chemical engineering Chemistry Organic and inorganic materials development Environmental engineering Separation process Nanotechnology Renewable energy Nutrients and resource recovery Journal of Applied Membrane Science & Technology (AMST) is published online with a frequency of three (3) issues per year (April, August and December)
Copyright of articles that appear in Journal of Applied Membrane Science & Technology belongs exclusively to Penerbit Universiti Teknologi Malaysia (Penerbit UTM Press). This copyright covers the rights to reproduce the article, including reprints, electronic reproductions, or any other reproductions of similar nature.
Development of Wood Ash-Derived Geopolymer for Adsorptive Removal of Copper from Aqueous Solution
Heavy metal contamination by copper poses significant environmental risks, necessitating efficient and sustainable treatment technologies. This study investigated the potential of wood ash-derived geopolymer as a low-cost adsorbent for Cu²⁺ removal from aqueous solutions. Wood ash (WA) obtained from Acacia mangium was alkali-activated with metakaolin (MK) to synthesise a wood ash–metakaolin geopolymer (WAMK). The materials were characterised using particle size analysis (PSA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). Batch adsorption experiments were conducted under different pH conditions to evaluate Cu²⁺ removal performance. PSA showed that WAMK possessed the smallest particle size (D(0.9) = 42.87 μm) compared with WA (70.19 μm) and MK (48.10 μm), indicating improved particle refinement following geopolymerisation. WAMK successfully formed a stable aluminosilicate geopolymer structure, as confirmed by FTIR and SEM-EDX analyses. Under acidic conditions (pH 5), WA exhibited the highest Cu²⁺ removal efficiency (101.38%), whereas WAMK and MK achieved removal efficiencies of 40.09% and 18.71%, respectively. At pH 10, all adsorbents exhibited adsorption capacities ranging from 6.52 to 6.74 mg g⁻¹ and 100% removal efficiencies, indicated that copper removal was influenced by both adsorption and Cu(OH)₂ precipitation under alkaline conditions. These findings demonstrate that solution pH plays a critical role in copper removal performance and that geopolymerisation successfully produced a structurally stable adsorbent with potential for sustainable wastewater treatment applications.
Copyright (c) 2026 Journal of Applied Membrane Science & Technology
Development of Zeolitic Imidazolate Framework-8/Polydimethylsiloxane Membrane with Primitive Structure for Carbon Dioxide Permeation Study
Membrane technology plays a vital role in carbon dioxide (CO­2) removal as one of the key actions to mitigate climate change. Additive manufacturing has emerged as an alternative method for membrane fabrication due to its high flexibility. Triply periodic minimal surface (TPMS) architectures are widely recognized for their high mechanical robustness and distinctive properties with continuous smooth geometry and zero mean curvature. These features facilitate seamless fluid flow across the structure, and thus, minimizing stagnant regions and reducing the risk of contamination. Among the TPMS structures, the primitive structure is notable for its high compressive strength and mechanical resistance. This study aims to fabricate and evaluate a primitive-structured zeolitic imidazolate framework-8 (ZIF-8)/polydimethylsiloxane (PDMS) mixed-matrix membrane with 2 × 1 × 1 cubic unit cell for carbon dioxide permeation using a sacrificial mold fabrication approach. The membrane was fabricated using a sacrificial mold printed via fused deposition modeling. The ZIF-8 fillers and membranes were characterized using field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The primitive-structured ZIF-8/PDMS membrane demonstrated CO­2 permeability and CO2/N2 ideal selectivity that are comparable to reported literature values, reaching 13.17 ± 0.57 × 10³ Barrer and 7.76 ± 0.28, respectively, at 0.025 bar. This suggests that removing the sacrificial mold through dissolution is unlikely to compromise the membrane surface, and therefore, represents a viable approach for the fabrication of membranes with complicated structures.
Statistically-assisted Optimization of PVDF-MWCNT-Triclosan Hybrid Membrane for High Flux, Salt Rejection, and Contact Angle
Membrane distillation offers a promising solution for water desalination, yet its broader application is severely hindered by biofouling and membrane wetting. To address these limitations, this study developed a novel polyvinylidene fluoride (PVDF) membrane enhanced with multi-walled carbon nanotubes (MWCNTs) and silica nanoparticles (SiO₂), cross-linked with epichlorohydrin (ECH), and coated with the antimicrobial agent triclosan (TCS), aimed at improving hydrophobicity and anti-biofouling properties. The membrane was fabricated via phase inversion and optimized using Response Surface Methodology with a Box-Behnken design across 17 experimental runs. Qualitatively, ATR-FTIR spectroscopy confirmed the successful incorporation of MWCNT (C=O ester at 1733.04 cm⁻¹), TCS (aromatic C=C at 1639.70 and 1452.91 cm⁻¹), and SiO₂ (Si–O–Si at 1070.80 cm⁻¹), while SEM revealed a porous cross-section with pore sizes reduced from ~450 nm to ~200 nm after TCS coating. Quantitatively, the optimal membrane (2 wt.% ECH, 1 wt.% TCS, 2 wt.% SiO₂) achieved a contact angle of 92.98°, a water flux of 11.05 kg·m⁻²·h⁻¹, and a salt rejection of 75.36%, with total porosity reaching 82.40%. The findings demonstrate that TCS functionalization successfully enhances hydrophobicity and flux, though salt rejection remains below industrial benchmarks. Further optimization of TCS dispersion and membrane formulation is necessary to achieve superhydrophobic performance (>150° contact angle) and >99% salt rejection for practical desalination applications.
Hydrothermally Synthesized CoMn₂O₄/Graphite Composite as a High-Capacity Anode for Lithium-Ion Batteries
The increasing demand for high-energy-density lithium-ion batteries (LIBs) drives the development of anode materials with capacities exceeding that of graphite (372 mAh g⁻¹). CoMn₂O₄, with a high theoretical capacity (921 mAh g⁻¹), is a promising candidate but suffers from low conductivity and severe volume expansion. In this work, a CoMn₂O₄/graphite (CMO/g) composite is developed to address these limitations through a synergistic effect. CoMn₂O₄ is synthesized via a hydrothermal method followed by calcination, and the sample treated at 700 °C exhibits the best crystallinity and morphology. Structural characterizations (XRD, FTIR, FESEM-EDX) confirm the successful formation of the composite and uniform distribution of CoMn₂O₄ on graphite. Electrochemical evaluations reveal that CMO/g-3 delivers a high initial discharge capacity of 2503 mAh g⁻¹ and maintains ~1000 mAh g⁻¹ after 100 cycles with nearly 100% coulombic efficiency and low charge-transfer resistance. A full cell assembled with CMO/g-3 and LiFePO₄ provides an initial discharge capacity of 146.5 mAh g⁻¹ at 0.2 A g-1, although capacity fading occurs upon prolonged cycling due to volume expansion effects. Overall, the CoMn₂O₄/graphite composite demonstrates enhanced electrochemical performance and promising potential as a high-capacity anode material for next-generation LIBs.
Selective Hydrogen Permeation and Transport Behaviour in Ruthenium-Impregnated Alumina Ceramic Membranes
Hydrogen and multi-gas permeation through ruthenium-impregnated alumina tubular membranes with nominal pore sizes of 15 nm and 6000 nm was investigated under non-reactive conditions at 100 °C and transmembrane pressure differences of 20–300 kPa. Single-gas permeation experiments using H₂, He, N₂, CO₂, and air were conducted to evaluate the influence of pore architecture and ruthenium incorporation on gas transport behaviour. For the 6000 nm membrane, the hydrogen flow rate increased from 1.09 to 8.39 L min⁻¹, whereas the 15 nm membrane exhibited hydrogen flow rates ranging from 0.97 to 4.61 L min⁻¹ over the same pressure range. Despite the 400-fold difference in nominal pore size, the larger-pore membrane exhibited only a modest increase in hydrogen permeation, indicating that gas transport was governed by the overall membrane architecture rather than nominal pore diameter alone. This experimentally observed deviation from ideal pore-size scaling highlights the important influence of pore connectivity, tortuosity, support-layer resistance, and effective transport pathways in asymmetric ceramic membranes. Knudsen number analysis showed that the 6000 nm membrane operated predominantly within the viscous-flow regime, whereas the 15 nm membrane exhibited transitional Knudsen–viscous transport with enhanced molecular discrimination. SEM, EDX, contact-angle measurements, and gravimetric catalyst-loading analysis confirmed successful ruthenium incorporation without severe pore blockage or structural degradation. The results demonstrate that membrane architecture and Ru-induced surface modification exert a greater influence on gas permeation behaviour than nominal pore size alone under the non-reactive operating conditions investigated. These findings provide new insight into structure–transport relationships in Ru-modified ceramic membranes and offer guidance for the design of hydrogen-selective ceramic membrane systems.
Development of Biodegradable Thermoplastic Potato Starch Formulations for Sustainable HVAC Air Filter Frames
The HVAC sector relies heavily on petroleum-based engineering plastics, particularly for rigid HEPA filter frames. Because these frames are permanently bonded to filter media, spent assemblies generate a massive landfill waste stream. This study investigates a sustainable alternative utilizing potato starch (Solanum tuberosum) plasticized with glycerol via hydrothermal gelatinization. The formulation systematically varied the plasticizer-to-starch weight ratio (0% to 100%) to optimize mechanical and environmental performance. Mechanical testing revealed an inverse relationship between plasticizer loading and ultimate tensile stress. The optimized formulation (25% wt. glycerol) achieved a maximum tensile strength of 2.940 MPa, balancing structural integrity with flexibility, while higher loadings drastically reduced capacity due to molecular lubrication. FTIR spectroscopy confirmed successful matrix plasticization and preservation of the primary polysaccharide backbone. Six-week terrestrial soil burial assays demonstrated continuous microbial and hydrolytic degradation across all thermoplastic starch formulations. The optimized matrix exhibited the fastest biodegradation kinetics, reaching a cumulative gravimetric mass loss of 79.09% by week six due to enhanced hydrophilicity and microbial accessibility. These findings demonstrate that plasticizer optimization can precisely tailor biopolymer properties, positioning potato starch-based frameworks as viable, eco-friendly candidates for disposable HVAC components and sustainable packaging.
Machine Learning in Membrane Distillation for Pulp and Paper Wastewater Treatment: A Review
Membrane distillation (MD) is a promising thermally driven separation technology for treating high-strength industrial wastewater, particularly from the pulp and paper industry. However, its performance is constrained by complex and nonlinear interactions among operating conditions, feed characteristics, and membrane properties, leading to challenges such as fouling, membrane wetting, and flux decline. Conventional modelling approaches are often inadequate in capturing these dynamic behaviours, resulting in limited predictive reliability. This review focuses on the application of machine learning (ML), with particular emphasis on artificial neural networks (ANNs), in enhancing MD performance prediction and optimization. ANN models have demonstrated strong capability in modelling nonlinear relationships and accurately predicting key performance indicators, including permeate flux, rejection efficiency, and fouling behaviour. Special attention is given to recent developments integrating ANN models with advanced membrane materials, such as polyvinylidene fluoride/cellulose nanocrystal (PVDF/CNC) composite membranes, to improve system efficiency and stability. Furthermore, probabilistic approaches, including Bayesian neural networks and Monte Carlo simulations, are discussed for uncertainty quantification and risk-informed decision-making. Key challenges, including data scarcity, model interpretability, and generalizability, are critically evaluated alongside emerging solutions such as explainable AI and digital twin systems. Overall, ANN-driven approaches offer significant potential to transform MD into a predictive, reliable, and intelligent wastewater treatment technology.
A Review on Engineering Approaches to Reverse Osmosis Brine Management: Disposal, Volume Reduction and Emerging Resource Recovery
Reverse osmosis (RO) desalination generates concentrated brine streams whose management remains a primary technical and regulatory constraint on system performance and sustainability. This review evaluates current and emerging RO brine management strategies with emphasis on operational feasibility, energy demand, and compliance drivers. Conventional disposal options remain dominant in practice but are increasingly limited by discharge regulations and environmental impact. Membrane-based, thermal, and hybrid processes can achieve significant brine volume reduction and support near-zero liquid discharge; however, these gains come with substantial energy penalties, fouling risks, and operational complexity. Resource recovery from seawater RO brines has progressed for major ions such as magnesium, calcium, and bulk salts, yet most pathways remain at laboratory or pilot scale, while recovery of trace elements is constrained by low concentrations, selectivity limits, and unfavorable process economics. Across all advanced options, the lack of long-term performance data, uncertain cost structures, and site-specific regulatory requirements continue to impede scale-up. The review concludes that near-term brine management is best achieved through incremental integration of volume reduction, energy recovery, and compliant discharge within existing treatment trains, rather than through standalone recovery systems.
Zeolite-incorporated PVDF Hollow Fiber Membrane Contactor for Carbon Dioxide Stripping from Water
Polyvinylidene fluoride (PVDF) hollow fiber mixed matrix membranes (HFMMMs) were prepared by incorporating hydrophobic Zeolite Socony Mobil–5 (ZSM-5) particles into the spinning dope. These membranes were then applied for CO₂ stripping from a diethanolamine (DEA) solution. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analyses were carried out to examine the membrane morphology and surface roughness. The cross-sectional SEM images showed that adding ZSM-5 changed the membrane structure from a sponge-like form to a finger-like configuration. AFM results indicated that surface roughness increased when ZSM-5 was introduced into the dope solution. In CO₂ stripping tests, both stripping flux and efficiency improved as the liquid-phase velocity increased, whereas changes in gas velocity had only a minor effect on the flux. For the HFMMM, the maximum CO₂ stripping flux reached 2.30 × 10⁻³ mol/m²·s, and the highest stripping efficiency was 83.3% at a liquid velocity of 0.7 m/s. When the liquid temperature was raised from 80 to 90 °C at the same velocity, the CO₂ flux further increased from 2.30 × 10⁻³ to 6.30 × 10⁻³ mol/m²·s. In long-term operation, the HFMMM exhibited better resistance to wetting and showed a smaller decline in flux. Over 120 h, the plain PVDF membrane experienced a flux reduction of 73.5%, while the HFMMM showed only a 24.2% decrease.
Book Review: Fundamentals of Membrane Separation Technology authored by Zhan Wang
This review evaluates Fundamentals of Membrane Separation Technology (Elsevier; 2024), authored by Prof. Zhan Wang [1], a senior membrane scientist from the Beijing University of Technology who has extensively contributed to polymeric membranes, membrane fabrication, and industrial membrane applications. It summarizes scope and structure, highlights the book’s major contributions to membrane science and engineering, comments on clarity and organization, notes teaching value and industrial usefulness. It also incorporates recent industrial trends such as digital monitoring, energy efficiency, hybrid processes, and sustainability considerations. The book offers a comprehensive treatment of membrane science, materials, fabrication, modeling, and applications, making it a valuable resource for graduate education and professional practice. While comprehensive, the book could include more quantitative case studies, expanded diagrams, and deeper coverage of emerging digital tools. Nevertheless, the book remains an authoritative and contemporary reference for students, researchers, and engineers across water treatment, bioprocessing, chemical processing, and environmental engineering.
Knudsen Number Sensitivity to Pressure Drop in Composite Ceramic Membranes
Gas transport in nanoscale ceramic membranes is fundamentally governed by the Knudsen number (Kn), which differentiates between molecular dominated and continuum dominated flow regimes. This study experimentally evaluates the sensitivity of Kn to transmembrane pressure across multilayer alumina membranes comprising a 15 nm selective layer, a 200 nm intermediate layer, and a 6000 nm macroporous support. Hydrogen (H₂), carbon dioxide (CO₂), and air were investigated at 100 °C over a pressure range of 20–300 kPa. The results consistently show an inverse relationship between Kn and pressure for all gases and pore sizes, as predicted by kinetic gas theory due to the pressure dependent decrease in molecular mean free path. Among the gases studied, hydrogen exhibits the strongest pressure sensitivity in the 15 nm layer, followed by CO₂ and air, reflecting differences in molecular size and diffusivity. Linear regression applied to the experimental Kn–ΔP trends yields coefficients of determination of R² ≈ 0.8875 across all gases and pore diameters, confirming high linearity and strong internal consistency in the measurements. Although the R² values remain constant, each gas exhibits a distinct regression slope and intercept, as shown in Figures 4–6, indicating differing Kn pressure response characteristics. Complementary SEM and dynamic wettability measurements further support the mechanistic interpretation. The 15 nm top layer shows the highest hydrophilicity (equilibrium contact angle ≈ 60°), promoting enhanced gas–wall interactions. The 200 nm layer exhibits intermediate wettability (≈ 70°), while the 6000 nm support is weakly hydrophobic (≈ 93°). These structural and surface properties help explain the observed trends: smaller and more hydrophilic pores intensify molecule–wall collisions, amplifying Knudsen-dominated transport. Overall, the findings provide validated experimental benchmarks for modelling rarefied gas transport in composite ceramic membranes, with implications for hydrogen purification, CO₂ separation, and catalytic membrane reactor design.
Recent Developments in Synthesis of Nanomaterial for Agriculture: The Role of Supercritical Fluid Technology
Fungal diseases, such as Ganoderma boninense, pose significant economic threats to oil palm plantations. Conventional fungicides, including synthetic and biofungicides, have been employed to manage these diseases, but they come with limitations such as environmental impact and limited efficacy. Other than that, weed infestation is another serious challenge in agricultural systems such as oil palm plantations. Synthetic herbicides and bioherbicides have been widely use to mitigate this problem but herbicides still have limitation in terms of health concerns. Recent advancements in nanotechnology have introduced nano-enabled crop protection most notably nanofungicides and nanoherbicides as promising alternatives, offering improved penetration and delivery of active ingredients. However, challenges such as non-uniform size distribution and polydispersity hinder their effectiveness. This review explores the potential of supercritical fluid technology (SFT) to overcome these limitations, providing a green and sustainable approach to nanoparticle production. SFT offers distinct advantages, including moderate operating temperatures and non-toxic solvents, aligning with the principles of green chemistry. The unique properties of SFT-produced nanomaterials, particularly their high surface area-to-volume ratio, demonstrate significant potential for membrane technology applications beyond agricultural contexts. Future perspectives highlight the need for further research to optimize SFT processes for agricultural applications, aiming to enhance the scalability and cost-effectiveness of nanofungicide and nanoherbicide production. The integration of SFT in agriculture could revolutionize plant disease and weed management, contributing to sustainable and eco-friendly practices.
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Efficient Adsorptive Removal of Methylene Blue Using Acid- and Alkali-Modified Clinoptilolite–Alginate Beads: High-Capacity Monolayer Adsorbents for Wastewater Treatment and Potential Membrane Applications
Methylene blue (MB) is a hazardous pollutant with severe impacts on human health and marine ecosystems. To solve these issues, this work investigates the removal of MB from wastewater using sodium alginate beads embedded with natural zeolite clinoptilolite (NZC) modified with HCl and NaOH. To comprehend the changes in NZC physicochemical properties, it was modified with different concentrations of HCl and NaOH (0.5, 1.0, 3.0, and 5.0 M) and extensively characterized using Fourier-transform infrared spectroscopy (FTIR-ATR), and nitrogen adsorption analysis. Both HCl-NZC and NaOH-NZC beads achieved 100% MB removal efficiency, with maximum adsorption capacities of 45.80 mg/g and 45.09 mg/g, respectively. The adsorption process followed the Langmuir isotherm model with high correlation value (R²) of 0.9952 (HCl-NZC) and 0.9907 (NaOH-NZC), indicating monolayer adsorption on a homogeneous surface. This study serves as a preliminary investigation into the adsorption behavior of acid- and base-modified NZC encapsulated in alginate beads for MB removal. The findings demonstrate that the modified beads exhibit strong adsorption capacity and stability, suggesting their potential application as fillers or active components in future zeolite-based composite membrane systems for efficient dye removal.
Evaluation of PASP–ZnO Nanocomposites as Eco-Friendly Scale Inhibitors for Calcium Carbonate Deposition
Carbonate scaling is a significant operational issue in oil and gas production and water treatment systems, leading to blockages and reduced efficiency. Conventional scale inhibitors often face environmental restrictions, prompting a shift towards greener alternatives like polyaspartic acid (PASP). However, the performance of traditional PASP is limited. This study evaluates an eco-friendly PASP–ZnO composite as an enhanced scale inhibitor for calcium carbonate. The nanocomposite was synthesized and characterized using Energy-Dispersive X-ray (EDX) and Fourier-Transform Infrared Spectroscopy (FTIR), which confirmed the successful incorporation of zinc. The scale inhibition performance was assessed through static inhibition tests and Scanning Electron Microscopy (SEM) analysis. Results showed that the PASP-Zn composite exhibited more stable and effective inhibition than pure PASP, reaching an efficiency of approximately 44.85% at a 50 ppm concentration. SEM images revealed that the composite significantly distorted the calcium carbonate crystal morphology, indicating its effectiveness in disrupting scale formation. These results indicate that the PASP–ZnO nanocomposite is an environmentally friendly and effective inhibitor for controlling calcium carbonate scaling and may also serve as a promising modifier for polymeric membranes to enhance their antifouling properties.
Preliminary Investigation on Enhanced Hydrogen Generation via Carbon Nanodots–Sulfonated Polyoctahedral Silsesquioxane Layer Modified Anode in Water Electrolysis
This study investigated the preliminary electrochemical performance of carbon anodes coated with a composite of Carbon Nanodots (CND) and Sulfonated Polyoctahedral Silsesquioxane (SPOSS) for water electrolysis. The coatings were applied in varying ratios of CND to SPOSS (1:0, 1:1, 0:1) and at different layer thicknesses (3 and 5 layers) simulating membrane-like interfaces for enhanced electrode–electrolyte interaction. Electrochemical performance was evaluated through hydrogen production rates in a 2 wt% NaOH electrolyte. Scanning Electron Microscopy (SEM) was used to confirm the uniformity and integrity of the coatings, while UV-Vis Spectroscopy was employed to assess any potential leaching of coating materials into the electrolyte. Results indicated that electrodes coated with CND:SPOSS (1:1) modification with three coating layers improved both catalytic activities, achieving the highest hydrogen production rate of 0.51 cm³/s. Excessive coating thickness, particularly at five layers, led to aggregation observed in the SEM images, which resulted in a reduced hydrogen production rate and overall performance. The 3-layer CND:SPOSS (1:1) coating is optimal for hydrogen production performance due to its uniform, crack-free structure and enhanced electrochemical activity, while the 3-layer CND:SPOSS (0:1) coating is best for minimizing leaching, as it shows the least absorbance increase. These preliminary findings highlight the potential of nanocarbon-based surface modification as a membrane-inspired strategy to enhance hydrogen production efficiency in alkaline water electrolysis systems.
High-efficiency Removal of Diclofenac via Advanced Technologies: A Comparative Study of Photocatalysis, Adsorption, and Nanofiltration
Pharmaceuticals are frequently detected in the environment due to their partially removal by the conventional wastewater treatment processes. In order to limit their accumulation in the environment, effective tertiary treatments must be employed. In the present study, the removal of Diclofenac (DCF), a nonsteroidal anti-inflammatory drug (NSAID) using three advanced water treatment technologies, i.e., photocatalysis, adsorption by activated carbon (AC) and nanofiltration (NF) was investigated. Titanium dioxide (TiO2) was used as a photocatalyst for the degradation of DCF and a removal of 100% was observed in the optimal conditions (pH= 5, Dose of TiO2=1 g. L-1 and [DCF]= 20 mg.L-1). Spent coffee grounds (SCG) as the AC exhibited a capacity of adsorption of 100 mg.g-1, contributing to 100% removal of DCF. On the other hand, the removal of DCF by NF membrane showed a high retention of 97% at 4 bars and reached 100% at 6 and 8 bars. A comparison between these three methods has shown that photocatalysis offers fast, complete pollutant degradation without secondary pollution and adsorption is cost-effective while NF is effective but challenged by fouling and waste issues. This study highlights effective and practical solutions for removing DCF from water, offering promising options to improve wastewater treatment and reduce pharmaceutical pollution.
Enhancing Superhydrophobic Polypropylene Membranes via Polypropylene Coating for Stable Membrane Distillation of Aquaculture Seawater
Membrane distillation (MD) suffers from membrane wetting due to inadequate surface hydrophobicity, which limits long-term flux stability and desalination performance. Electrospun polypropylene (PP) membranes offer a promising solution because of their high porosity and interconnected fibrous structure that promote vapor transport. However, neat electrospun PP membranes often fall short of achieving the superhydrophobicity needed for durable wetting resistance, restricting their practical use in MD. To address this limitation, this study employed a dip-coating approach to deposit hydrophobic PP layers onto electrospun membranes, introducing a roughened surface that enhances hydrophobicity and mitigates wetting. Two coating formulations, i.e. low-viscosity (PP-L) and high-viscosity (PP-H), were examined. Morphological characterization revealed that PP-L coatings penetrated the membrane matrix, causing pore blockage and a severe flux decline (PPM-C3-L: 1.2 kg/m2·h, 87.7% lower than neat PP). In contrast, PP-H coatings formed stereoscopic surface agglomerates without compromising porosity (82%) and achieving superhydrophobicity with a static contact angle of 156.7°. The optimal single-layer PP-H coated membrane (PPM-C1-H) maintained a high and stable flux of 13.3 kg/m2·h for 25 h, with 99.98% salt rejection when treating aquaculture seawater. SEM–EDS analysis confirmed negligible scaling and no pore wetting despite the presence of CaSO4, NaCl, and SiO2 precursors in the feed. Overall, dip-coated PP-H surface offers a scalable approach to improve PP membranes for long-term, stable, and high-quality desalination of complex aquaculture effluents.
Fabrication and Characterization of PVDF/PVP/TiO₂ Membrane for Ultrafiltration Process
The growing demand for high-quality water has intensified efforts to advance membrane-based purification technologies, with polyvinylidene fluoride (PVDF) remaining a dominant material despite its intrinsic hydrophobicity and propensity for fouling. This study seeks to improve the functional performance of PVDF membranes through the incorporation of titanium dioxide (TiO₂) nanoparticles, introducing hydrophilic characteristics and promoting hydroxyl radical formation. PVDF/polyvinylpyrrolidone (PVP) membranes were fabricated via the phase inversion method with TiO₂ loadings of 0%, 1%, and 2%, followed by comprehensive characterization using SEM, FTIR, contact angle measurements, and pure-water flux analysis. The incorporation of TiO₂ resulted in a notable enlargement of pore size from 370 nm (0% TiO₂) to 530 nm (1%) and 580 nm (2%). FTIR spectra further verified structural interactions between the PVDF matrix and TiO₂ nanoparticles. Membrane hydrophilicity improved substantially, as reflected in the reduction of contact angle from 78.6° to 67.1° and 43.8°, accompanied by a pronounced increase in water flux from 49 to 148 and 150 L/m²·h. These findings demonstrate that TiO₂ incorporation effectively optimizes the membrane’s pore architecture, surface wettability, and permeability, thereby reinforcing its suitability for enhancing PVDF-based ultrafiltration systems in water treatment applications.
Structural, Thermal, and Surface Properties of PVDF/Silica Aerogel Nanocomposite Membranes for Membrane Distillation Application
This study addresses membrane distillation's key challenges - wetting and thermal inefficiency - by developing PVDF/silica aerogel nanocomposite membranes with optimized sublayer properties. We fabricated membranes with systematic variations in PVDF concentration (12-21%) and silica aerogel loading (1-3%), characterizing their structural and surface properties. FTIR analysis confirmed successful nanoparticle incorporation without altering PVDF chemistry. Porosity exhibited concentration-dependent behavior: increasing with silica at 12% PVDF, stable at 18%, and decreasing at 21% due to viscosity effects on phase separation. All nanocomposites showed reduced thermal conductivity, enhancing insulation. While skin layer hydrophobicity remained constant, silica migration significantly increased sublayer contacts angles (peak 130.6° for 18% PVDF/3% silica, 20% improvement over control). The 18% PVDF formulation demonstrated optimal balance, maintaining structural integrity while achieving high porosity (78.3%) and low thermal conductivity (0.048 W/mK). These results highlight two critical findings: (1) PVDF concentration dictates nanoparticle effects on membrane morphology, and (2) strategic silica incorporation simultaneously enhances sublayer hydrophobicity and thermal resistance without compromising mechanical stability. The study provides a design framework for MD membranes, demonstrating how sublayer engineering can mitigate wetting while improving thermal efficiency - crucial advancements for practical MD implementation.
Investigation of Carbon Dioxide and Nitrogen Gases Permeability through PEBAX 1657/PEG/graphene Oxide Nanoparticle Mixed Matrix Membrane
This study investigated gas permeation of neat and blend polyether block amide (PEBAX) 1657 membranes. Polyethylene glycol (PEG) and graphene oxide (GO) were added to PEBAX membrane matrix at different concentration to study their effects on the morphology, permeability and selectivity of the membranes. The prepared membranes were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The permeabilities of pure gases CO2 and N2 were carried out using a constant pressure-variable volume method. The influence of PEBAX 1657 membranes with different weight fractions of PEG and GO on the gas permeation performance were studied. The modified membrane with PEBAX/PEG (40 wt.%) displayed the optimum gas separation performance with a CO2 permeability of 103.9 Barrer and selectivity of 56.3 for the CO2/N2 gas pair at 10 bar and room temperature. The permeability of this membrane was twofold compared to the pristine PEBAX, under the same temperature and pressure conditions, showing promising prospects for CO2 capture.
Book Review Membrane Technology and Applications 3rd and 4th Edition
The book Membrane Technology and Applications by Richard W. Baker has long served as a foundational reference for researchers in the field of membrane technology. It covers a wide range of fundamental concepts and practical applications of membranes in areas such as gas separation, water purification, and pervaporation. This review highlights the key differences between the third and fourth editions of the book. Significant updates and new data introduced in the fourth edition are also discussed. The inclusion of up-to-date technologies aligned with the latest 12 years of development in membrane science provides valuable insights to researchers, ensuring the book remains relevant and reflective of current trends in the field. As membrane technology continues to evolve, the design of treatment systems has become increasingly complex, requiring more advanced configurations and integration with other processes. At the same time, the nature of the chemicals to be treated—ranging from emerging contaminants to high-strength industrial effluents—has also grown more diverse and challenging. This complexity underscores the need for up-to-date knowledge, like that provided in the book, to support researchers in developing effective and innovative membrane solutions.
Effect of Hot Pressing Parameters on the Performance of Graphene Oxide Speek Membrane Electrode Assembly for Proton Exchange Membrane Fuel Cell Application
Fuel cells have garnered significant research attention over the past decades due to their versatility across portable, transportation, and stationary applications. Among various types, the Proton Exchange Membrane Fuel Cell (PEMFC) stands out as the most promising due to its ability to generate clean energy using hydrogen and oxygen without carbon dioxide emissions. Nafion, the commercial proton-conducting membrane used in PEMFCs, offers excellent proton conductivity along with high chemical and thermal stability. However, its high cost and limited operational temperature range (up to 80 °C) poses significant challenges for practical applications. Therefore, this study explores a cost-effective alternative nanocomposite membrane based on sulfonated polyether ether ketone (SPEEK) incorporated with graphene oxide (GO) as a carbonaceous filler. GO was synthesized via a modified Hummer’s method and integrated into the SPEEK matrix. The resulting nanocomposite membrane was characterized using Scanning Electron Microscopy (SEM) for morphological analysis and Fourier Transform Infrared (FTIR) spectroscopy to identify functional groups. The Membrane Electrode Assembly (MEA) was optimized using hot-pressing at 110 °C under 5 tons for 4 minutes, achieving a peak power output of 184.02 mW. The results demonstrate that the inclusion of GO enhances the performance of the PEM, positioning GO-SPEEK as a promising and cost-effective substitute for Nafion in PEMFC applications.
Book Review pH Responsive Membranes: Biomedical Applications
Biomedical science is a broad interdisciplinary field that integrates biology and medicine, aiming to improve diagnosis, treatment, and disease prevention. Membrane technology plays a significant role in this domain, particularly in drug delivery, hemodialysis, chemical sensing, and the purification of pharmaceutical products. These include the recovery of antibodies and enzymes, protein concentration, and the reclamation of ultrapure water for processing and cleaning. As highlighted by the authors, pH-responsive membranes are typically composed of two main polymer groups: carboxyl-containing polyacids and pyridine-based polybases. These polymers swell and ionize differently depending on the surrounding pH, resulting in tunable permeability and selectivity. This book offers a novel consolidation of responsive membrane principles with a focus on biomedical applications. References span both foundational and emerging research, providing a balanced representation of state-of-the-art developments. It bridges theoretical transport models and real-world use cases, offering a valuable reference for material selection, design, and functional optimisation of pH-responsive membranes.
Book Review Experimental Methods for Membrane Applications in Desalination and Water Treatment
Membrane technology plays a crucial role in desalination and water treatment, offering efficient solutions to water scarcity and contamination challenges. The book “Experimental Methods for Membrane Applications in Desalination and Water Treatment,” edited by Sergio G. Salinas-Rodríguez and Loreen O. Villacorte, serves as a comprehensive guide to experimental techniques, performance assessment, and fouling control in membrane-based water treatment processes. Published by IWA Publishing in 2024, this book comprises 19 chapters that cover a wide range of membrane applications in both academic and industrial settings.
A Review of Synthetic Polymers in Hemodialysis Membranes: Impact on Biocompatibility and Performance
A wide range of synthetic polymers is employed in hemodialysis (HD) applications, each offering unique advantages and potential limitations that can impact patient outcomes. These polymers are primarily chosen for their excellent permeability to uremic solutes and superior biocompatibility, which are critical for efficient blood purification. However, challenges such as membrane fouling, protein adsorption and long-term blood compatibility remain concerns that can affect the overall efficacy and safety of the treatment. In recent years, advances in polymer engineering have led to the development of new membrane materials with improved selectivity, durability, and reduced inflammatory response. Polysulfone (PS), polyurethane (PU), polyethersulfone (PES) and polyacrylonitrile (PAN) are among the most widely used polymers in commercial dialyzers, each with specific performance characteristics tailored to patient needs. In the current review, we overviewed various types of polymers used as hemodialyzer material and their contribution to enhance patient life span.
Copra Biochar Pyrolysis Optimization for Cr(VI) Removal and Membrane Incorporation Potential
Pyrolyzed coconut copra biochar (PCB) is a primary byproduct produced during the pyrolysis process of coconut copra biomass. This study focused on the effect of increasing pyrolysis temperature on the characteristics and hexavalent chromium (Cr(VI)) removal potential of the PCB as adsorbent and membrane precursor. Copra, a readily available agricultural waste in Malaysia, was utilized as the biochar precursor to produce PCB at 300-500 °C, 5 °C/min heating rate and 1 hour residence time. Then, PCB was incorporated into a polyvinylidene fluoride (PVDF) membrane using the dry/wet phase inversion technique, with varied biochar loadings (0 to 1 wt.%). The produced PCB were characterized using CHNS elemental analysis, Fourier transform Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Brunaue-Emmett-Teller (BET) surface analysis and pH drift analysis to assess morphology, functional groups, surface area, porosity and pH point of zero charge, respectively. Adsorption isotherm study shows the best fit with Langmuir and Freundlich model. Adsorption kinetics study shows pseudo-second order model fit better than the pseudo-first-order model. Then, preliminary incorporation tests of optimized PCB in PVDF membrane analyzed using water uptake and porosity analysis, water contact angle and performance analysis via cross flow system to assess water flux and Cr(VI) removal. It was found at 450 °C pyrolysis temperature produced copra biochar with relatively high carbon content of 72 %, the highest pore volume of 6.168 10-3 cm3/g with adsorption capacity of 10.41 mg/g and Cr(VI) removal of 27.98 %. As PCB loading in the PVDF membranes increased from 0 to 0.4 wt.%, it was found that the membrane porosity increased from 7 % to 62 % resulted in the enhancement of the water flux achieving maximum 2.04 Lm-2h-1 at 0.5 g/L loading and Cr(VI) removal achieving 33.33 %. This has shown good potential of copra biochar as adsorbent and incorporation to develop adsorptive membrane for heavy metal removal.
Underwater Oleophobicity of MBPP Membrane Modified by TiO₂/PDMS/IPA for Oil/Water Emulsion Separation
Meltblowing of polypropylene (PP) without using toxic solvents is a feasible method for mass-producing fibrous membranes for oil/water emulsion separation. However, the oleophilicity of PP can lead to fouling due to significant oil adsorption, and the low integrity of the PP fiber can cause the membrane structural failure during filtration operations. In this work, polydimethylsiloxane (PDMS) and isopropyl alcohol (IPA) are employed to improve the inter-fiber adhesion while maintaining the void structure that allows water permeation. Hydrophilic TiO2 nanoparticles are deposited on the meltblown PP membrane (MBPP) using a suspension dispersion method, transforming the membrane into an underwater oleophobic surface. The results show that the TiO2/PDMS/IPA modified MBPP membrane is oleophilic towards palm oil but oleophobic towards toluene under water. Because of the long chain and high molecular weight of triglycerides in palm oil, they form stronger intermolecular interactions with both the pristine and modified MBPP membrane surfaces. The underwater oil contact angle (UWOCA) of MBPP membrane varies between 5.1 ± 5° and 70.7 ± 6.3° when in contact with palm oil droplets. The UWOCA of toluene droplets increased from 67.4 ± 20.8° to 133.8 ± 18.1° when the TiO2 loading was increased from 0 to 0.2 wt%. The optimal membrane with 0.2 wt% TiO2 nanoparticles achieved the maximum flux at 25040 ± 2403 L/m2 h and the separation efficiency > 99% for the toluene/water emulsion system. During the cyclic test, fouling from toluene adsorption occurred during cycle #3, but the separation efficiency remained greater than 98% after five cycles.
Effect of Coating Concentration on Gas Separation Performance of Polysulfone Mixed Matrix Membrane for Biomethane Recovery from Wastewater
Anaerobic membrane bioreactor (AnMBR) provides a range of benefits which include high performance in extracting organic matter and energy production in the form of biogas. In this study, performance of mixed matrix membrane (MMM) to recover biomethane from wastewater was studied. Polymer matrix of polysulfone (Psf) incorporated with different inorganic fillers, halloysite nanotubes (HNT) and activated carbon (AC). Different concentration (3%, 4% and 5%) of MMM’s polydimethylsiloxane (PDMS) coating were examined by using scanning electron microscopy (SEM-EDX) and gas permeation tests. The morphological structures as well as permeability and selectivity of MMM towards carbon dioxide (CO2) and methane (CH4) were investigated. SEM analysis showed that increasing the concentration increases the thickness of the coated surface of the membrane. For MMMs-HNT, the thickness of the top layer increased 29.1% from the uncoated membrane to the highest concentration of PDMS coating while MMMs-AC showed the thickness of the membrane increased by 64.7%. The EDX results showed that there is 46% increase and 9.63% increased of silicon composition for both MMMs-HNT and MMMs-AC. For the gas separation performance, PDMS coated MMMs showed lower permeability but higher selectivity than uncoated MMMs. The highest selectivity of the membrane can be observed in 3wt% PDMS coated MMMs-HNT which is 15.83 with CO2 and CH4 permeance of 0.76 and 0.05 GPU, respectively.
A Review on Membrane Fabrication: Structure, Properties and Performance Relationship
Polymeric membranes have been widely explored and applied in both academic and industrial sectors. Their high separation efficiency, versatility, and scalability make them an alternative to conventional separation processes. This review presents recent developments in flat-sheet polymeric membranes for water treatment applications, focusing on fabrication methods, membrane formulation parameters, and structure-property-performance relationships. Common fabrication methods, including phase inversion, interfacial polymerization, stretching, track-etching, and electrospinning, are examined in terms of fabrication mechanisms, operating conditions and membrane structures. While these methods may utilize similar base polymers, they result in distinct membrane structures that are customized to specific applications. In addition, the influence of formulation parameters, such as polymer and solvent selection, polymer concentration, and additives used, are thoroughly discussed to obtain desired physicochemical properties for specific membrane applications. Furthermore, the membrane structural properties, including crystallinity, pore morphology, and surface characteristics, like hydrophilicity, surface charge, and roughness, are discussed to better understand their impact on membrane permeability and solute selectivity. Advanced characterization techniques for analysing these properties are also explored. Lastly, this review explores future directions for polymeric membrane technology in respect to the materials used, post-treatment of used membrane, the integration with artificial intelligence technologies, and assessment on industrial scalability of modified membrane. By integrating recent advancements, addressing existing challenges, and identifying future opportunities, this review provides a foundation for advancing polymeric membrane technologies and promoting innovation in water treatment solutions.
Machine Learning for Accelerating Development of Ion Conducting Membranes for Fuel Cell Applications
Fuel cells such as polymer electrolyte membrane fuel cells are playing crucial role in the transition towards sustainable energy systems. Ion conducting membranes (ICMs) are playing critical chemical and mechanical roles in such fuel cells which directly affecting the efficiency, durability and overall device performance. Recent progress in machine learning (ML) is introducing powerful tools to aid in the discovery, design, and optimization of membrane materials that is likely to lead to quicker and more cost-effective materials development cycles. This article discusses the significant potential of applying ML research and development of new generation of ICMs for polymer electrolyte membrane fuel cells. The scope is overviewing types of polymer electrolyte membrane fuel cells and their operation environments with different ICMs in addition to present status and technical challenges for development new ICMs. Moreover, the key ML algorithms for ion exchange membranes (IEMs) development techniques together with available ML frameworks and their potential uses in optimization of membranes structural properties, performance prediction, and new materials discovery are discussed. The challenges and the future directional approaches to accelerate the development of robust ICMs using ML driven research that ultimately improving the sustainability and efficiency of fuel cell technologies are elaborated.