Search Results (419)

Municipal wastewaters pose a severe risk to the environment and human health when discharged untreated. This is due to their high content of pathogens, such as viruses and bacteria, which can cause diseases like cholera. Herein, the research and development of porphyrin-modified polyethersulfone (PES) ultrafiltration (UF) membranes was conducted to improve bacterial inactivation in complex municipal wastewater and enhance the fouling resistance and filtration performance. The synthesis and fabrication of porphyrin nanofillers and the resultant membrane characteristics were studied. The incorporation of porphyrin-based nanofillers improved the membrane’s hydrophilicity, morphology, and flux (247 Lm⁻² h⁻¹), with the membrane contact angle (CA) decreasing from 90° to ranging between 58° and 50°. The membrane performance was monitored for its flux, antifouling properties, reusability potential, municipal wastewater, and humic acid. The modified membranes demonstrated an effective application in wastewater treatment, achieving notable antibacterial activity, particularly under light exposure. The In-BP@SW/PES membrane demonstrated effective antimicrobial photodynamic effects against both Gram-positive S. aureus and Gram-negative E. coli. It achieved at least a 3-log reduction in bacterial viability, meeting Food and Drug Administration (FDA) standards for efficient antimicrobial materials. Among the variants tested, membranes modified with In-PB@SW nanofillers exhibited superior antifouling properties with flux recovery ratios (FRRs) of 78.9% for the humic acid (HA) solution and 85% for the municipal wastewater (MWW), suggesting a strong potential for long-term filtration use. These results highlight the promise of porphyrin-functionalized membranes as multifunctional tools in advanced water treatment technologies. Full article

Current work investigates the fabrication and performance of nanocomposite membranes, modified with varying concentrations of hybrid nanostructures comprising titanium nanowires coated with iron nanoparticles (TiO₂ NWs-Fe₂O₃), for the removal of Naphthol Blue Black (NBB) dye from industrial wastewater. A series of analytical tools were employed to confirm the successful modification including scanning electron microscopy and EDX analysis, porosity and hydrophilicity measurements, Fourier-transform infrared spectroscopy, and X-Ray Diffraction. The incorporation of TiO₂ NWs-Fe₂O₃ has enhanced membrane performance significantly by increasing the PWF and improving dye retention rates of nanocomposite membranes. At 0.7 g of nanostructure content, the modified membrane (M8) achieved a PWF of 93 L/m²·h and NBB dye rejection of over 98%. The flux recovery ratio (FRR) analysis disclosed improved antifouling properties, with the M8 membrane demonstrating a 73.4% FRR. This study confirms the potential of TiO₂ NWs-Fe₂O₃-modified membranes in enhancing water treatment processes, offering a promising solution for industrial wastewater treatment. These outstanding results highlight the potential of the novel PES-TiO₂ NWs-Fe₂O₃ membranes for dye removal and present adequate guidance for the modification of membrane physical properties in the field of wastewater treatment. Full article

Access to clean water is a pressing global concern and membrane technologies play a vital role in addressing this challenge. Thin-film composite membranes prepared via interfacial polymerization (IPol) using meta-phenylenediamine (MPD) and trimesoyl chloride (TMC) exhibit excellent separation performance, but face limitations such as fouling and low hydrophilicity. This study investigated the interaction between MPD and sulfonated zinc phthalocyanine, Zn(SO₂⁻)₄Pc, as a potential strategy for enhancing membrane properties. Using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT), we analyzed the optimized geometries, electronic structures, UV–Vis absorption spectra, FT-IR vibrational spectra, and molecular electrostatic potentials of MPD, Zn(SO₂⁻)₄Pc, and their complexes. The results show that MPD/Zn(SO₂⁻)₄Pc exhibits reduced HOMO-LUMO energy gaps and enhanced charge delocalization, particularly in aqueous environments, indicating improved stability and reactivity. Spectroscopic features confirmed strong interactions via hydrogen bonding and π–π stacking, suggesting that Zn(SO₂⁻)₄Pc can act as a co-monomer or additive during IPol to improve polyamide membrane functionality. A conformational analysis of MPD/Zn(SO₂⁻)₄Pc was conducted using density functional theory (DFT) to evaluate the impact of dihedral rotation on molecular stability. The 120° conformation was identified as the most stable, due to favorable π–π interactions and intramolecular hydrogen bonding. These findings offer computational evidence for the design of high-performance membranes with enhanced antifouling, selectivity, and structural integrity for sustainable water treatment applications. Full article

In accordance with growing environmental pressures and the demand for sustainable industrial practices, membrane technologies have emerged as key enablers for increasing efficiency, reducing emissions, and supporting circular processes across multiple sectors. This review focuses on the integration among microalgae-based systems, offering innovative and sustainable solutions for biomass production, carbon capture, and industrial wastewater treatment. In cultivation, membrane photobioreactors (MPBRs) have demonstrated biomass productivity up to nine times greater than that of conventional systems and significant reductions in water (above 75%) and energy (approximately 0.75 kWh/m³) footprints. For carbon capture, hollow fiber membranes and hybrid configurations increase CO₂ transfer rates by up to 300%, achieving utilization efficiencies above 85%. Coupling membrane systems with industrial effluents has enabled nutrient removal efficiencies of up to 97% for nitrogen and 93% for phosphorus, contributing to environmental remediation and resource recovery. This review also highlights recent innovations, such as self-forming dynamic membranes, magnetically induced vibration systems, antifouling surface modifications, and advanced control strategies that optimize process performance and energy use. These advancements position membrane-based microalgae systems as promising platforms for carbon-neutral biorefineries and sustainable industrial operations, particularly in the oil and gas, mining, and environmental technology sectors, which are aligned with global climate goals and the UN Sustainable Development Goals (SDGs). Full article

Membrane fouling poses a significant challenge in the widespread adoption and cost-effective operation of membrane technology. Among different strategies to mitigate fouling, dynamic membrane (DM) technology has emerged as a promising one for effective control and mitigation of membrane fouling. Silicon carbide (SiC) membranes have attracted considerable attention as membrane materials due to their remarkable advantages, yet membrane fouling is still inevitable in challenging separation tasks, such as oil-in-water (O/W) emulsion separation, and thus effective mitigation of membrane fouling is essential to maximize their economic viability. This study investigates the use of pre-deposited oxide DMs to mitigate the fouling of SiC membranes during the separation of O/W emulsions. Among five screened oxides (Fe₂O₃, SiO₂, TiO₂, ZrO₂, Al₂O₃), SiO₂ emerged as the most effective DM material due to its favorable combination of particle size, negative surface charge, hydrophilicity, and underwater oleophobicity, leading to minimized oil droplet adhesion via electrostatic repulsion to DM surfaces and enhanced antifouling performance. Parameter optimization in dead-end mode revealed a DM deposition amount of 300 g/m², a transmembrane pressure (TMP) of 0.25 bar, and a backwashing pressure of 2 bar as ideal conditions, achieving stable oil rejection (~93%) and high pure water flux recovery ratios (FRR, >90%). Cross-flow filtration outperformed dead-end mode, maintaining normalized permeate fluxes of ~0.4–0.5 (cf. ~0.2 in dead-end) and slower FRR decline, attributed to reduced concentration polarization and enhanced DM stability under tangential flow. Optimal cross-flow conditions included a DM preparation time of 20 min, a TMP of 0.25 bar, and a flow velocity of 0.34 m/s. The results establish SiO₂-based DMs as a cost-effective strategy to enhance SiC membrane longevity and efficiency in O/W emulsion separation. Full article

Tertiary amine oxide (TAO)-containing zwitterionic polymers are a class of zwitterionic materials formed by the oxidation of tertiary amine groups. In recent years, polymers such as poly(2-(N-oxide-N,N-diethylamino)ethyl methacrylate) (OPDEA) have gained significant attention due to their unique antifouling properties, dynamic cell membrane affinity, and responsiveness to microenvironments. These characteristics have made them promising candidates in drug delivery, antibiofouling, and precision therapy. Compared to traditional polyethylene glycol (PEG), these polymers not only exhibit long-circulation properties but can also overcome biological barriers through active transport mechanisms, making them a research hotspot in the field of next-generation biomaterials. This review comprehensively summarizes the recent advancements in this field, covering aspects such as the synthesis, properties, applications, and mechanisms of TAO-containing zwitterionic polymers. Full article

The efficient removal of emulsified oil and trace organic pollutants via forward osmosis (FO) technology remains challenging due to limited water flux and membrane fouling. In this study, a series of metal oxide-modified PES-based composite FO membranes were fabricated and systematically evaluated to compare the effects of ZnO, Al₂O₃, and CuO nanoparticles on membrane structure and separation performance. The results demonstrated that the membrane modified with 0.04 g of ZnO nanoparticles achieved optimal synergy in terms of hydrophilicity, surface charge, and pore structure. The pure water flux increased from 5.48 L·m⁻²·h⁻¹ for the pristine membrane to 18.5 L·m⁻²·h⁻¹ for the ZnO-modified membrane, exhibiting a 237.5% increase in pure water flux compared to the pristine PES membrane, an oil rejection rate exceeding 97%, and over 95% rejection of typical negatively charged trace organic pollutants such as ibuprofen and tetracycline. Moreover, the ZnO-modified membrane showed excellent antifouling performance and structural stability in various organic solvent systems. This study not only optimized the interfacial chemistry and microstructure of the FO membrane but also enhanced pollutant repellence and the self-cleaning capability through increased hydrophilicity and surface negative charge density. These findings highlight the significant potential of ZnO modification for enhancing the overall performance of FO membranes and provide an effective strategy for developing high-performance, broadly applicable FO membranes for complex water purification. Full article

Membrane technologies are used in the production of potable water and the treatment of wastewater in the military forces, providing the highest level of contaminant removal at an energy-efficient cost. This review examines the integration and application of membrane technologies, including reverse osmosis, nanofiltration, ultrafiltration, electrodialysis and advanced hybrid systems, in the treatment of wastewater generated at military bases, naval vessels and submarines. Special emphasis is placed on purification technologies for chemically, biologically and radiologically contaminated wastewater, as well as on the recycling and treatment of wastewater streams by mobile systems used in military applications. Given the specific requirements of complex military infrastructures, particularly in terms of energy efficiency, unit self-sufficiency and reduced dependence on logistical supply chains, this work analyses the latest advances in membrane technologies. Innovations such as nanographene membranes, biomimetic membranes, antifouling membrane systems and hybrid configurations of forward osmosis/reverse osmosis and electrodialysis/reverse electrodialysis offer unique potential for implementation in modular and mobile water treatment systems. In addition, the integration and operational use of these advanced technologies serve as a foundation for the development of autonomous military water supply strategies tailored to extreme operational conditions. The continued advancement and optimization of membrane technologies in military contexts is expected to significantly impact operational sustainability while minimizing environmental impact. Full article

Polymer membranes often face challenges of oil fouling and rapid water flux decline during the separation of oil-in-water emulsions, making them a focal point of ongoing research and development efforts. Coating PVDF membranes with a hydrogel layer equips the developed membranes with robust potential to mitigate oil fouling. However, developing a controllable thickness of a stable hydrogel layer to prevent the blocking of membrane pores remains a critical issue. In this work, atmospheric pressure low-temperature plasma was used to prepare the surface of a PVDF membrane to improve its wettability and adhesion properties for coating with a thin hydrophilic film of an AM-NaA copolymer hydrogel. The AM-NaA/PVDF membrane exhibited superhydrophilic and underwater superoleophobic properties, along with exceptional anti-crude oil-fouling characteristics and a self-cleaning function. The AM-NaA/PVDF membrane achieved high separation efficiency, exceeding 99% for various oil-in-water emulsions, with residual oil content in the permeate of less than 10 mg/L after a single-step separation. Additionally, it showed a high-water flux of 5874 L/m²·h for crude oil-in-water emulsions. The AM-NaA/PVDF membrane showed good stability and easy cleaning by water washing over multiple crude oil-in-water emulsion separation and regeneration cycles. Adding CaCl₂ destabilized emulsions by promoting oil droplet coalescence, further boosting flux. This strategy provides a practical pathway for the development of highly reusable and oil-fouling-resistant membranes for the efficient separation of emulsified oily water. Full article

Membrane technology has received great attention in the desalination and water treatment sectors over the last few decades. However, membrane fouling remains a critical issue that affects membrane performance, a phenomenon common in membrane bioreactors (MBRs). This major drawback can be overcome by the preparation of antifouling membranes using an electrospinning technique that generates a hydrophilic modification of membranes. In this study, nanocomposite polyvinylidene fluoride (PVDF) and cellulose acetate (CA) polymer was fabricated to mitigate membrane fouling. Surface and mechanical characterization of the electrospun membrane was performed to assess morphology, chemical composition, and hydrophilic/hydrophobic properties. Anti-fouling performance of the composite PVDF/CA membrane was evaluated versus a neat PVDF membrane through bench-scale experiments. The PVDF/CA nanofiber membrane displayed a more hydrophilic nature, demonstrated by a lower water contact angle (101° vs. 115°) and increased wastewater flux (190 L/m²·h. vs. 160 L/m²·h), although the composite membrane demonstrated lower tensile strength (2.0 ± 0.1 MPa vs. 1.7 ± 0.1 MPa). The new material demonstrated greater anti-fouling performance compared to the neat PVDF membrane. Results suggest that this nanofiber material shows promise as an enhanced antifouling membrane that can overcome membrane fouling limitations. Full article

Thread-based analytical devices are low-cost, portable, and easy to use, making them ideal for detecting various biomolecules like glucose and DNA with minimal sample requirements, while also offering environmental benefits through their biodegradability. This study explores the potential of zwitterionic poly(sulfobetaine methacrylate) brushes modified cotton thread (PSBMA@threads) as an innovative substitute for DNA solid-phase extraction. The PSBMA polymer brushes were synthesized on cotton threads via surface-initiated atom transfer radical polymerization (SI-ATRP). The usability of the PSBMA@threads for DNA extraction from cell lysates containing cell debris, proteins, and detergents was evaluated. Characterization using SEM, FTIR, and EDS confirmed the successful functionalization with PSBMA polymer brushes. The antifouling properties of PSBMA@threads, including resistance to non-specific protein adsorption and underwater oil repellency, were assessed. The results demonstrated selective DNA capture from protein and lipid-rich lysates. Optimized extraction parameters improved DNA yield, enabling efficient extraction from tumor cells, which successfully underwent PCR amplification. Comparative experiments with commercial silica membrane-based columns revealed that PSBMA@threads exhibited comparable DNA extraction capability. The PSBMA@threads maintained extraction capability after six months of ambient storage, highlighting its stability and cost-effectiveness for nucleic acid isolation in analytical applications. Full article

Microcystin-LR (MCLR) is a toxin produced by harmful algal blooms that is emerging as a threat to drinking and recreational water systems worldwide. Nanofiltration (NF) is an effective technique for purifying contaminated water sources; however, membrane fouling caused by coexisting organic matter limits the practicality of the process. This research studies the use of an electrocoagulation (EC) pretreatment to limit fouling during the NF process. Water for this study was taken from Lake Fayetteville, a local body of water where MCLR concentrations have been recorded to be >15 µg/L. EC was performed using polyaluminum chloride as a background electrolyte at various operating conditions. EC-treated water was then further treated with NF to assess the impact of the EC pretreatment on NF fouling. It was found that the larger particle size of the sludge produced using aluminum electrodes at pH 7 had the best combination of settling ability and organic carbon removal (92%). This also led to the smallest flux decline during six-hour NF experiments of just 9%. These results highlight the potential of an EC pretreatment as an antifouling technique for the NF treatment of water contaminated with algal toxins. Full article

Copper-based nanoparticles (as Cu₂O) are a key component in marine antifouling paints and, as coatings degrade, release nanoparticles that can affect a wide range of non-target organisms. This study investigates the impact of Cu₂O nanoparticles on the early development of urchins Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis, and benchmarks their toxicity against similarly sized Cu and CuO nanoparticles and ionic copper. Concentration-dependent toxicity was noted for all forms of copper at concentrations in the 1 to 5000 µg L⁻¹ range. EC₅₀ values after Cu₂O exposure indicated that A. lixula (99 µg L⁻¹) was generally more sensitive than the other two species, with EC₅₀ values of 371 µg L⁻¹ and 606 µg L⁻¹ noted for S. granularis and P. lividus, respectively. The same trend across species was noted for both Cu and CuO, although these nanoparticles generally showed higher EC₅₀ values, indicating lower toxicity compared to Cu₂O. LC₅₀ values qualitatively parallel the corresponding EC₅₀ values, with Cu₂O consistently the most toxic, while Cu was less harmful, and CuO did not reach LC₅₀ at any concentration. Again, greatest lethality was noted in A. lixula. While copper ion release from Cu was much greater than from CuO and Cu₂O, the latter showed similar or greater toxicity to developing embryos compared to Cu. This indicates that copper ions are not the sole driver of toxicity of Cu₂O, but there may also be a contribution derived from Cu₂O redox activity within cells or at membranes that negatively impact oxidative stress defence mechanisms and metabolic pathways. Full article

Accelerated urbanization and industrialization have significantly heightened water contamination risks, posing severe threats to public health and ecological balance. Polymeric membranes stand at the forefront of addressing this challenge, revolutionizing water and wastewater treatment. These membranes adeptly remove a broad spectrum of contaminants, including organic compounds and heavy metals, thereby playing a crucial role in mitigating environmental pollution. This research delves into the sophisticated mechanisms of polymeric membranes in filtering out pollutants, with a spotlight on the enhancements brought about by nanotechnology. This includes a detailed examination of their inherent antibacterial properties, showcasing their innovative design and potential for extensive application. The study further investigates advanced techniques like electrochemical processes and membrane distillation, particularly focusing on desalination. These methods are central to the advancement of water purification, emphasizing efficiency and environmental sustainability. However, challenges such as membrane fouling pose significant hurdles, necessitating ongoing research into surface modifications and antifouling strategies. This paper offers a comparative analysis of various membrane technologies, highlighting their manufacturing complexities and efficiency benchmarks. In summation, the paper underscores the importance of continuous innovation in membrane technology, aiming to develop sustainable and effective water treatment solutions. By bridging the gap between basic science and technological advancements, this review aims to guide practitioners and researchers towards a future where clean water is universally accessible, ensuring the preservation of our ecosystems. Full article

Access to clean water remains a critical global challenge, exacerbated by population growth, industrial activity, and climate change. In response, this study presents the development and characterization of thermo-responsive and salt-adaptive ultrafiltration membranes functionalized with a poly(N-isopropylacrylamide)–co-poly(dimethylacrylamide) (PNIPAM-co-PDMAC) copolymer. By combining the thermo-responsive properties of PNIPAM with the hydrophilic characteristics of PDMAC, these membranes exhibit dual-stimuli responsiveness to temperature and ionic strength, allowing for precise control of permeability and fouling resistance. The experimental results demonstrated that the copolymer’s hydration state and dynamic pore size modulation are sensitive to changes in salinity and temperature, with sodium chloride (NaCl) significantly influencing the transition behavior. Preliminary fouling tests confirmed the antifouling capabilities of these membranes, with salt-triggered hydration transitions effectively reducing irreversible fouling and extending membrane durability. The membranes’ reversible properties and adaptability to dynamic operating conditions highlight their potential to enhance the efficiency and sustainability of water treatment processes. Future investigations will focus on scaling up the fabrication process and assessing the long-term stability of these membranes under real-world conditions. This study underscores the promise of smart membrane systems for advancing global water sustainability. Full article