Water Filtration Membranes Research Articles

Bacterial cellulose-graphene oxide composite membranes with enhanced fouling resistance for bio-effluents management

Bacterial cellulose composites hold promise as renewable bioinspired materials for industrial and environmental applications. However, their use as free-standing water filtration membranes is hindered by low compressive strength, fouling, and poor contaminant selectivity. This study investigates the potential of bacterial cellulose-graphene oxide composites membranes for fouling resistance in pressure-driven filtration. Graphene oxide dispersed in poly(ethylene glycol) (PEG-400) is incorporated as a reinforcing filler into 3D network of bacterial cellulose using an in-situ synthesis method. The effect of graphene oxide on in situ fermentation yield and the formation of percolated-network in the composites shows that the optimal membrane properties are reached at a graphene oxide loading of 2 mg/mL. The two-dimensional graphene oxide nanosheets uniformly dispersed into the matrix of bacterial cellulose nanofibers via hydrogen-bonded interactions demonstrated nearly twofold higher water flux (380 L m−2 h−1) with a molecular weight cut-off ranging between 100–200 KDa and a sixfold increase in wet compression strength than pristine BC. When exposed to synthetic organic foulants and bacterial rich feed solutions, the composite membranes showed more than 95% flux recovery. Additionally, the membranes achieved over 95% rejection of synthetic natural organic matter and bacterial rich solutions, showcasing their enhanced fouling resistance and selectivity.

Upcycling waste polymer membranes through eco-friendly solvent-catalysed valorisation for energy and environmental solutions

A facile pathway of upcycling waste/discarded polysulfone (WPSF) membranes has been proposed using deep eutectic solvent (DES) system composed of choline chloride and ethylene glycol (CC:EG) in 1:1 ratio as a green template. This approach offers a viable solution for addressing polymer membrane waste management challenges while simultaneously promoting feasible method, resource efficiency and economic viability. The WPSF was doped with Mn ions prior to the solvothermal conversion at 200 °C and pyrolysis at 900 °C. The obtained functional porous carbon showed superior adsorption capacity towards Malachite green (MG) (423.72 mg/g), Eriochrome black-T (EBT) (326.79 mg/g), Diclofenac (DCF) (195.31 mg/g), and Ofloxacin (OFX) (121.8 mg/g). The adsorption followed pseudo second order kinetics and well agreed with Langmuir isotherm. Further, the optimised carbon material i.e., Mn-WPSF-01 was used as an adsorptive-based membrane water filtration system, in which a remarkable water flux about 965 L.m−2.h−1 for different feed streams with outstanding rejection of >90% even after ten cycles of regeneration was obtained. Therefore, Mn-doped carbon materials integrate the advantages of easy preparation, robustness, and effective adsorption performances, as well as good recyclability. Furthermore, the utilized or secondary carbon materials were used as electrode system in supercapacitors after the pyrolysis, where they displayed a specific capacitance of 110.88 F/g at 0.1 A/g of current density with capacity retention 90.85% for about 20,000 cycles with a current density increased to 5 A/g. Therefore, this approach promises to recycle the WPSF via potential applications in water treatment and energy applications through greener way.

Tannic acid non-covalent functionalized two-dimensional h-BN membrane for efficient water filtration

Tannic acid (TA) non-covalent functionalized hexagonal boron nitride (h-BN) two-dimensional (2D) membrane (TA/h-BN) was developed by π-π interaction between h-BN and TA. The π-π interaction between h-BN and TA eliminated the agglomeration of h-BN nanosheets because of strong Van der Waals' force, and TA/h-BN nanosheets showed improved membrane forming ability. Separation performance of h-BN membrane was improved significantly after the TA non-covalent functionalization on h-BN nanosheets. TA/h-BN membrane with a thickness of 650 nm presented a water permeance of 600 L m−2 h−1 bar−1 and a rejection rate of 91 % for Congo red (CR). Moreover, prepressed TA/h-BN membrane with a thickness of 1150 nm under 3 bar for 7 h could remove 90 % of [Fe(CN)6]3-, and this prepressed membrane exhibited excellent stability during a 72 h of cross-flow filtration, suggesting its broad application prospects in water filtration.

Fabrication of Flat Tubular Clay-Based Porous Support Filters

Objective: Mongolia has few freshwater resources. It is therefore important to conserve water resources. An efficient possibility is to purify water and reuse it. Therefore, the scientists from the Material Science Center of the Mongolian University of Science and Technology collaborated with the researcher from the Korea Institute of Material Science and carried out a project between 2017-2020. Theoretical Framework: In this study, Mongolian zeolites and prepared kaolin were used and flat tubular porous support was extruded by a double screw vacuum extruder at KIMS. Method: The supports were burned at 800 and 1000°C and the properties such as pore distribution were determined by mercury porosimetry Results and Discussion: The zeolite-kaolin support had a bulk density of 1.46 g/cm3, a porosity of 41.52% and, an average pore size of 218 nm. With its water permeability of 115 L/m2·h at 0.01 MPa and 970 L/m2·h at 0.08 MPa, the support achieved good results. Research Implications: The wastewater treatment tests show that these membranes also have good compressive strengths. We have cleaned the sewage from a leather factory, which was very highly contaminated and has high viscosity. Originality/Value: Since there is no chemical industry in Mongolia, raw materials for synthetic materials are imported. The main significance of this research work lies in determining the possibility of producing ceramic membranes for water filtration using the mineral resources of our country, and it will serve as the basis for future research.

Comparative analysis of high-performance UF membranes with sulfonated polyaniline: Improving hydrophilicity and antifouling capabilities for water purification

Ultrafiltration is vital for wastewater treatment and industrial processes like food production and pharmaceuticals. This comprehensive study investigates the intricate development and performance evaluation of advanced composite membranes composed of sulfonated polyethersulfone (SPES), polyaniline (PANI), and sulfonated polyaniline (SPANI). Spectroscopic analyses (FTIR and XRD) confirm successful PANI and SPANI integration with the SPES matrix. Thermogravimetric assessment shows improved thermal stability in SPES-SPANI 3 % membranes with a higher decomposition temperature than pristine membranes. Morphological analysis via FESEM reveals structural changes in nanocomposite membranes, highlighting PANI and SPANI’s impact on microscale morphology. Mechanical testing indicates significant elongation increase and enhanced flexibility in SPES-SPANI 3 % membranes. Physicochemical characterizations demonstrate heightened porosity, water uptake, and surface hydrophilicity with PANI and SPANI incorporation. Permeability tests show a substantial increase in pure water flux, reaching 220 Lm-2h−1 for SPES-SPANI 3 % membranes. Antifouling effectiveness is evident through lower flux values for foulants (HA, BSA, SA, and NOM) compared to pure water. The hybrid membranes exhibited remarkable resistance to fouling, removing more than 98.69 %, 99.23 %, and 99.49 % of BSA, HA, and SA, respectively, without compromising their rejection rates. Long-term durability assessments confirm stable performance, with SPES-SPANI 3 % membranes recovering 98 % of the initial flux after three cycles. This investigation highlights the robust of SPES-SPANI 3 % membranes for water filtration, emphasizing improved thermal stability, morphological enhancements, flexibility, and superior antifouling and rejection capabilities. These findings offer crucial insights for developing advanced membranes in efficient and durable water purification technologies.

Removal of cadmium and chromium heavy metals from aqueous medium using composite bacterial cellulose membrane

Bacterial cellulose (BC) membranes produced from biomass are emerging as an eco-friendly solution for water decontamination. The abundance of hydroxyl groups and the high surface-to-volume ratio of this material allow for the integration of diverse functional groups, providing the potential for targeted water purification applications. Beyond their intriguing mechanical properties and unique complex structure, bacterial cellulose membranes are biodegradable into sugar molecules and can be processed with minimal handling and using mild chemicals. Taken together, these features make them a compelling choice for water filtration in the context of environmental responsibility. In their natural state, BC membranes have limited potential for targeted wastewater treatment. One strategy for enhancing their functionality is to graft customized molecules onto their surface. Therefore, this study aims to impart multifunctionality to BC membrane for water filtration. Hence a novel precursor with hard and soft base functionalities consisting of amines, carbonyls, amides, hydroxyls etc. is designed and grafted onto BC membranes, grown to ensure surface uniformity and membrane-to-membrane repeatability of the properties. The structure of the synthesized precursors and the effective functionalization of the membrane are then validated through various structural characterization techniques. Changes in the morphology of BC membranes are examined using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Both the pristine and modified BC membranes undergo a series of tests to assess their filtration capabilities under low-pressure regime and their efficiency in removing representative cadmium and chromium ions. The modified BC membrane exhibits superior filtration performance and water permeability than pristine-BC. The targeted metal ions were rejected more than 90% from the effluent. The modified membranes demonstrated a flux recovery of above 90% maintaining its effectiveness even after five successive cleaning-filtration cycles.

Harnessing plastic waste for sustainable membrane filtration with trimodal structure through acid-catalyzed oxidation

Polyolefin waste is among the most generated yet least recycled. Despite its potential as a feedstock of superhydrophobic membranes for organic solvent filtration, it remains a challenge to achieve high selectivity and permeability for viscous oils. In this study, we valorized polyolefin waste into trimodal water filtration membranes through acid-catalyzed oxidation and a void inducer. This approach enabled the creation of membranes with exceptional wettability and strength, characterized by a combination of micropores, macrovoids (30–70 µm), and cavities (150–200 µm). The acid-catalyzed oxidation introduced oxygen moieties into the membrane structure, resulting in a reduced water contact angle, improved hydrophilicity, and increased permeability. The micropores facilitated capillary action, macrovoids enabled efficient water passage, and cavities acted as oil reservoirs, for optimal oil–water separation. Various membranes were synthesized using low-density and high-density polyethylene (PE), polypropylene (PP), and their blend. The obtained results were compared with commercial membranes, revealing a flow rate of 43 ml/min, a retention capacity of 261 mg, and an oil removal efficiency ranging from 84–94 %. Furthermore, the membranes exhibited recyclability, demonstrating stability over at least 10 cycles. This hybrid process transforms plastic waste into trimodal water filtration membranes, achieving a balance between superoleophilicity and hydrophilicity.

Recent advancement on water filtration membranes: Navigating biofouling challenges

This study investigates the field of antifouling membranes for water filtration and desalination applications, specifically focusing on two-dimensional materials. The study examines the importance of these membranes in the context of climate change and its effects on coastal ecosystems. The occurrence of biofouling in seawater desalination membranes is closely connected to intricate processes influenced by factors such as water quality, microbial communities, hydrodynamics, and membrane properties. Microorganism adhesion initiates the process, which then advances into irreversible attachment and the creation of biofilm. Detached pieces contribute to the perpetuation of fouling. Biofouling is caused by a variety of biomaterials and organics, including bacteria, extracellular polymeric substances (EPS), proteins, and humic compounds. Innovative methods such as surface alterations using two-dimensional materials like graphene and graphene oxide, as well as the use of biofouling-resistant materials, provide promising possibilities. These materials have antifouling characteristics, making them environmentally beneficial options that reduce the need for chemical cleaning. Their application improves the water treatment process by preventing fouling and enhancing membrane performance. Real-world research applications can enhance and optimize these tactics to effectively reduce biofouling in seawater desalination systems, hence improving efficiency and sustainability. This is particularly important in light of climate change and its impact on coastal ecosystems. The findings obtained from the literature review emphasise the utmost significance of tackling biofouling in the face of a changing environment, particularly with regard to microorganisms. Important factors to consider are the selection of coating materials, the implementation of environmentally friendly cleaning solutions made from natural chemicals, and the improvement of pretreatment systems. Green cleaning agents are important eco-friendly alternatives to typical biocides, as they possess antibacterial, antifungal, and antifouling capabilities. Given the existence of climate change, these observations serve as a basis for promoting environmentally friendly methods in water treatment technology.

Green Synthesis of Nanocomposite Membranes for Sustainable Water Filtration

In order to tackle the worldwide problems of water pollution and shortage, this work explores the green synthesis of nanocomposite membranes for sustainable water filtering. Graphene oxide, cellulose nanocrystals, and silver nanoparticles were used as nanofillers in the fabrication of nanocomposite membranes, which were made using renewable polymer matrix (PES, PVDF, PAN). By including different polymer matrices and nanofillers, the composition analysis demonstrated the adaptability of nanocomposite membrane manufacturing, enabling the customization of membrane characteristics. Improved membrane shape and structural integrity were shown to result from the homogeneous dispersion of nanofillers inside the polymer matrix, according to characterization tests. Nanocomposite membranes demonstrated high flux rates and rejection rates for different pollutants, confirming their excellent performance in filtration experiments. The membranes’ improved fouling resistance also increased their service life and decreased the frequency of maintenance needs. Supporting the eco-friendliness of nanocomposite membrane production, an environmental impact evaluation found that it used less energy and generated less trash than traditional techniques. All things considered, nanocomposite membranes have shown great promise as long-term water treatment solutions due to their superior performance, durability, and environmental friendliness, as well as their effective production and characterisation. More study is needed to perfect membrane characteristics and solve the remaining problems that prevent their broad use in water treatment systems.

Waste cellulose acetate-based dynamic membrane for NOM-containing river water filtration

Excessive leaching of natural organic matter (NOM) from swamp forests into water resources poses significant challenges for water treatment plants, primarily due to its high variability. In this study, a waste-based cellulose acetate (W-CA) membrane was explored as a dynamic membrane for the filtration of real river water containing NOM and compared to a commercial-based CA (C-CA) membrane. The membranes were fabricated and thoroughly characterized. The results revealed that the W-CA membrane exhibited greater hydrophilicity, as indicated by a static contact angle of 84°, compared to the hydrophobic nature of the C-CA membrane (104°). The mean pore diameters of the C-CA and W-CA membranes were 4.4 µm and 5.3 µm, respectively, suitable as the base for a dynamic filter. The formation of a dynamic cake filtration layer (identified mainly as humic and fulvic acids) was confirmed from visual observation, SEM image and the decrease in the pore sizes. It was further validated from the cake layer as the dominant fouling mechanism obtained from a curve fitting analysis. Despite the W-CA and C-CA membranes respectively showed a high steady-state river water permeabilities of 348 and 226 L/(m2 h bar) respectively, they were still unable to fully remove NOM (27% removal for W-CA and 39% removal for C-CA membrane), suggesting the necessity for further developments. This study underscores the potential of W-CA membranes for water treatment while promoting a circular economy by converting waste into valuable resources and sustainable products.

Preparation and Characterization of Polyethersulfone/Activated Carbon Composite Membranes for Water Filtration.

Ultrafiltration membrane technology holds promise for wastewater treatment, but its widespread application is hindered by fouling and flux reduction issues. One effective strategy for enhancing ultrafiltration membranes involves incorporating activated carbon powder. In this study, composite polyethersulfone (PES) ultrafiltration membranes were fabricated to include activated carbon powder concentrations between 0 and 1.5 wt.%, with carbon size fixed at 200 mesh. The ultrafiltration membranes were evaluated in terms of membrane morphology, hydrophilicity, pure water flux, equilibrium water content, porosity, average pore size, protein separation, and E-coli bacteria removal. It was found that the addition of activated carbon to PES membranes resulted in improvements in some key properties. By incorporating activated carbon powder, the hydrophilicity of PES membranes was enhanced, lowering the contact angle from 60° to 47.3° for composite membranes (1.0 wt.% of activated carbon) compared to the pristine PES membrane. Water flux tests showed that the 1.0 wt.% composite membrane yielded the highest flux, with an improvement of nearly double the initial value at 2 bar, without compromising bovine serum albumin rejection or bacterial removal capabilities. This study also found that the inclusion of activated carbon had a minor impact on the membrane's porosity and equilibrium water content. Overall, these insights will be beneficial in determining the optimal concentration of activated carbon powder for PES ultrafiltration membranes.

Draft genome sequence of Sphingomonas paucimobilis strain Sph5, isolated from tap water filtration membrane.

Sphingomonadaceae are common membrane colonizers and biofilm formers. As part of our studies on long-term genetic changes in drinking water biofilm species, we report the draft genome sequence of Sphingomonas strain Sph5, isolated from a tap water filtration membrane. The isolate was determined as Sphingomonas paucimobilis through whole genome sequencing and de novo assembly.

Electrospun controlled release anti-quorum sensing filter for biofouling prevention in MCE membranes

The formation of biofilm on the surface of water filtration membranes results in decreased flux through the filter and output of contaminated water despite filtration. The reduction in clean water output due to biofilm diminishes filtration efficiencies and feasibility of filtration in regions where alternatives do not exist. In this work, we sought to lower biofouling concerns through examination of anti-quorum sensing (anti-QS) molecules in P. aeruginosa (PAO1). QS plays a critical initial role in biofilm formation. Therefore, we hypothesized that disruption of this communication mechanism at the filtration surface would result in lower biofilm growth and higher water outputs. An electrospun filter coating was developed to prevent biofilm formation on the surface of filtration membranes. The filter coating was deposited by electrospinning (ES) fibers that contained a polymer blend made up of one hydrophobic (polycaprolactone, PCL) and one hydrophilic (polyethylene glycol, PEG) polymer to provide controlled release of anti-quorum sensing molecules (Urolithin A) to prevent biofilm formation for an extended filtration test. Results showed that a 3:1 PCL to PEG polymer blend coating containing Urolithin A (200 µg/mL) provided significant physical disruption as well as molecular interruption of biofilm formation as compared to the pristine membrane (83.48 % reduction). While fibers exhibited smooth morphologies prior to nanofiltration tests, the fibers became porous after 4 hr tests in areas where PEG had dissolved and released Urolithin A. The controlled release of anti-QS molecules by electrospun fibers provided a significantly improved anti-biofilm methodology, improving biovolume reduction by 26.05 % and increasing flux by 52.78 % as compared to similar technologies reported. In addition to these findings, this work demonstrated Urolithin A disruption of PAO1 motility on agar (65.29 % reduction @ 100 µg/mL) and reduction in biofilm thickness (84.15 % reduction @ 200 µg/mL) by dissolution from electrospun fibers in liquid culture.

Halloysite Nanotube-Enhanced Polyacrylonitrile Ultrafiltration Membranes: Fabrication, Characterization, and Performance Evaluation.

This research focuses on the production and characterization of pristine polyacrylonitrile (PAN) as well as halloysite nanotube (HNT)-doped PAN ultrafiltration (UF) membranes via the phase inversion technique. Membranes containing 0.1, 0.5, and 1% wt HNT in 16% wt PAN are fabricated, and their chemical compositions are examined using Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) is utilized to characterize the membranes' surface and cross-sectional morphologies. Atomic force microscopy (AFM) is employed to assess the roughness of the PAN/HNT membrane. Thermal characterization is conducted using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA), while contact angle and water content measurements reveal the hydrophilic/hydrophobic properties. The pure water flux (PWF) performance of the porous UF water filtration membranes is evaluated at 3 bar, with porosity and mean pore size calculations. The iron (Fe), manganese (Mn), and total organic carbon (TOC) removal efficiencies of PAN/HNT membranes from dam water are examined, and the surfaces of fouled membranes are investigated by using SEM post-treatment. Mechanical characterization encompasses tensile testing, the Mori-Tanaka homogenization approach, and finite element analysis. The findings offer valuable insights into the impact of HNT doping on PAN membrane characteristics and performance, which will inform future membrane development initiatives.

Enhancing Mechanical Properties and Flux of Nanofibre Membranes for Water Filtration.

Nanofibres have gained attention for their highly porous structure, narrow pore size, and high specific surface area. One of the most efficient techniques for producing nanofibres is electrospinning. These fibres are used in various fields, including water filtration. Although they possess the ability to filter various components, the fibres generally have low mechanical strength, which can mitigate their performance over time. To address this, studies have focused on enhancing nanofibre membrane strength for water filtration. Previous analyses show that the mechanical properties of nanofibre mats can be improved through solvent vapour treatment, thermal treatment, and chemical crosslinking. These treatments promote interfibre bonding, leading to the improvement of mechanical strength. However, excessive treatment alters nanofibre behaviour. Excessive heat exposure reduces interfibre bonding, while too much solvent vapour decreases pore size and mechanical strength. Thus, a comprehensive understanding of these post-treatments is crucial. This review examines post-treatments aiming to increase the mechanical strength of nanofibre mats, discussing their advantages and disadvantages. Understanding these treatments is essential for optimising nanofibre membrane performance in water filtration and other applications.

Construction of tight ultrafiltration membrane for efficient dye/salt separation with physical and chemical self-healing property

This work developed a novel self-healing tight UF membrane based on damages to membrane during operation and cleaning via blending AMPS-PANI into the membrane matrix, which can not only endow the membrane with physical and chemical self-healing properties, but also enable the membrane to obtain effective separation performance of inorganic salt and dyes. Taking AMPS-PANI membrane (M4) as an example, the self-healing test showed that the dye/salt rejection rates of M4 membrane recovered to near pre-damage levels (more than 98%) for the physical damage. As for chemical damage, the high-resolution XPS spectra of S 2p of M4 membrane after damage displayed a larger S-C-C peak area than that before damage. The above results prove that the membrane has self-healing ability after physical and chemical damage. The observed physical self-healing property is ascribed to the swelling behavior of AMPS hydrogels, the fluidity of hydrogel chains and strong hydrogen bonding, and owing the chemical self-healing property to the Michael addition reaction between carbon–carbon double bonds and free radicals. The pure water flux, dye/salt rejection rate, structure, mechanical properties and porosity of the self-healing tight UF membrane were systematically investigated to evaluate its feasibility as an actual filtration membrane for textile wastewater. The results of the research indicate that membrane including both physical and chemical self-healing is a promising way to improve water filtration membrane with self-healing ability.

Emulsion Assembly of Graphene Oxide/Polymer Composite Membranes.

Graphene oxide/polymer composite water filtration membranes were developed via coalescence of graphene oxide (GO) stabilized Pickering emulsions around a porosity-generating polymer. Triptycene poly(ether ether sulfone)-CH2NH2:HCl polymer interacts with the GO at the water-oil interface, resulting in stable Pickering emulsions. When they are deposited and dried on polytetrafluoroethylene substrate, the emulsions fuse to form a continuous GO/polymer composite membrane. X-ray diffraction and scanning electron microscopy demonstrate that the intersheet spacing and thickness of the membranes increased with increasing polymer concentration, confirming the polymer as the spacer between the GO sheets. The water filtration capability of the composite membranes was tested by removing Rose Bengal from water, mimicking separations of weak black liquor waste. The composite membrane achieved 65% rejection and 2500 g m-2 h-1 bar-1. With high polymer and GO loading, composite membranes give superior rejection and permeance performance when compared with a GO membrane. This methodology for fabrication membranes via GO/polymer Pickering emulsions produces membranes with a homogeneous morphology and robust chemical separation strength.

Membrane Fabrication by Solid Waste: Opportunities and Challenges

Solid waste mismanagement is a global issue caused by population growth, industrialization, and daily human activity. Currently, the majority of trash produced is either dumped in landfills in affluent countries or open pits in poor nations. In addition to necessitating a great deal of land area, landfilling and open dumping may cause other environmental difficulties. In fact, solid wastes may provide many chances for reusing as raw materials for the creation of useful, high-value goods in response to the need for a circular economy. Due to their cheap prices, possible high removal efficiency for pollutants, renewable and sustainable qualities, solid waste-derived membranes have gained considerable research attention as a waste-to-resource solution for a variety of water treatment applications. The fabrication and applications of economical membranes manufactured from natural resources have been reported. However, comprehensive reviews that discuss the fabrication, properties and potential applications waste-generated membranes are still limited. The features and material recoverable resources for membrane production are emphasized in this study. Based on biopolymers, plastics, and inorganics recycled materials, a summary of membrane manufacturing and performance using recoverable resources for liquid separation applications is provided. There are many prospects in this fascinating field since waste-derived membrane for water filtration is a new technology. For converting solid wastes into useful membrane products for water treatment, this evaluation offers crucial advice.

State-of-the-Art of Polymer/Fullerene C60 Nanocomposite Membranes for Water Treatment: Conceptions, Structural Diversity and Topographies.

To secure existing water resources is one of the imposing challenges to attain sustainability and ecofriendly world. Subsequently, several advanced technologies have been developed for water treatment. The most successful methodology considered so far is the development of water filtration membranes for desalination, ion permeation, and microbes handling. Various types of membranes have been industrialized including nanofiltration, microfiltration, reverse osmosis, and ultrafiltration membranes. Among polymeric nanocomposites, nanocarbon (fullerene, graphene, and carbon nanotubes)-reinforced nanomaterials have gained research attention owing to notable properties/applications. Here, fullerene has gained important stance amid carbonaceous nanofillers due to zero dimensionality, high surface areas, and exceptional physical properties such as optical, electrical, thermal, mechanical, and other characteristics. Accordingly, a very important application of polymer/fullerene C60 nanocomposites has been observed in the membrane sector. This review is basically focused on talented applications of polymer/fullerene nanocomposite membranes in water treatment. The polymer/fullerene nanostructures bring about numerous revolutions in the field of high-performance membranes because of better permeation, water flux, selectivity, and separation performance. The purpose of this pioneering review is to highlight and summarize current advances in the field of water purification/treatment using polymer and fullerene-based nanocomposite membranes. Particular emphasis is placed on the development of fullerene embedded into a variety of polymer membranes (Nafion, polysulfone, polyamide, polystyrene, etc.) and effects on the enhanced properties and performance of the resulting water treatment membranes. Polymer/fullerene nanocomposite membranes have been developed using solution casting, phase inversion, electrospinning, solid phase synthesis, and other facile methods. The structural diversity of polymer/fullerene nanocomposites facilitates membrane separation processes, especially for valuable or toxic metal ions, salts, and microorganisms. Current challenges and opportunities for future research have also been discussed. Future research on these innovative membrane materials may overwhelm design and performance-related challenging factors.

Antibacterial Activity of Silver Nanoflake (SNF)-Blended Polysulfone Ultrafiltration Membrane

The aim of this research was to study the possibility of using silver nanoflakes (SNFs) as an antibacterial agent in polysulfone (PSF) membranes. SNFs at different concentrations (0.1, 0.2, 0.3 and 0.4 wt.%) were added to a PSF membrane dope solution. To investigate the effect of SNFs on membrane performance and properties, the water contact angle, protein separation, average pore size and molecular weight cutoffs were measured, and water flux and antibacterial tests were conducted. The antimicrobial activities of the SNFs were investigated using Escherichia coli taken from river water. The results showed that PSF membranes blended with 0.1 wt.% SNFs have contact angles of 55°, which is less than that of the pristine PSF membrane (81°), exhibiting the highest pure water flux. Molecular weight cutoff values of the blended membranes indicated that the presence of SNFs does not lead to enlargement of the membrane pore size. The rejection of protein (egg albumin) was improved with the addition of 0.1 wt.% SNFs. The SNFs showed antimicrobial activity against Escherichia coli, where the killing rate was dependent on the SNF concentration in the membranes. The identified bacterial colonies that appeared on the membranes decreased with increasing SNF concentration. PSF membranes blended with SNF, to a great degree, possess quality performance across several indicators, showing great potential to be employed as water filtration membranes.