Nanocomposite Membranes For Water Treatment Research Articles

Fabrication and performance evaluation of polycarbonate/polyvinyl alcohol–titanium dioxide thin‐film nanocomposite membranes for water treatment

AbstractIn recent years, there has been growing interest in using polymer nanocomposite membranes as a more advanced method for removing pollutants from water and treating wastewater for various purposes. In this study, thin‐film nanocomposite (TFN) membranes of polycarbonate/polyvinyl alcohol–titanium dioxide thin‐film (PC/PVA–TiO2) were fabricated by dip‐coating a PC substrate in a PVA/TiO2 solution. Various methods, including attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy, field emission scanning electron microscopy (FE‐SEM), atomic force microscopy (AFM), and water contact angle were utilized to assess the structural characteristics of the produced membranes. The PC/PVA thin‐film composite (TFC) and PC/PVA–TiO2 TFN membranes were then examined in a submerged membrane system to evaluate their effectiveness in filtering humic acid (HA) under various vacuum transmembrane pressure (0.3 and 0.6 bar) condition. The FTIR‐ATR results confirmed the formation of the active layer of PVA/TiO2 nanoparticles (NPs). It was observed that adding 1 wt.% of TiO2 NPs to the active layer of PVA/TiO2 significantly enhanced the water contact angle from 77.5° for PC support to 55.3° for PC/PVA–TiO2 (0.1) TFN membranes. Furthermore, the FE‐SEM results confirmed the formation of an active layer of PVA/TiO2 with a thickness of 237.87 nm. The pure water flux increased from 101.64 L/m2h for the PC/PVA TFC membrane to 144.02 L/m2h and 199.09 L/m2h for the PC/PVA–TiO2 (0.05) and PC/PVA–TiO2 (0.1) TFN membranes, respectively. Also, the results revealed that at lower transmembrane pressure, all membranes showed higher value in HA removal as compared to when higher transmembrane pressure was used.

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.

Synthesis of heterogeneous metal organic Framework-Graphene oxide nanocomposite membranes for water treatment

Textile wastewater is one of the most challenging streams for wastewater treatment as it is heavily contaminated with solid pollutants such as dyes. Nanofiltration (NF) membranes are a promising method to protect water resources by removing dyes and other organic contaminants from wastewater. In this study, novel NF membranes composed of a thin layer of graphene oxide (GO) and Zn-based metal–organic framework (ZIF-7) nanocomposites deposited on chitosan (CTS)-coated polyethersulfone (PES) substrate were fabricated to remove DIRECT RED 16 (DR16) dyes and humic acid from synthetic wastewater. The membrane structure was characterized using a variety of characterization methods such as SEM, XPS, FTIR, AFM, EDX, and water contact angle measurements. Introducing the GO-ZIF-7 nanocomposite layer improved the surface hydrophilicity of membranes by decreasing the contact angle from 84.9 % to 64.5 % for CTS-coated and 5GO-ZIF-7 modified membranes, respectively. This resulted in a greater dye removal rate for the modified membrane (∼94 %) compared to the original CTS-coated membrane (∼84 %). However, the pure water flux was reduced by 11.4 % due to the introduction of additional resistance layers. Furthermore, the addition of GO-ZIF-7 enhanced the antifouling and anti-biofouling characteristics of modified membranes against various organic and biological foulants, such as sodium alginate and Escherichia coli (E.coli). Overall, the fabricated membrane showed great dye filtration, antifouling, and anti-biofouling performances, by introducing high hydrophilicity, biocidal activities, and a negative surface charge to the membrane surface.

Effect of Transmembrane Pressure on Antifouling Properties of PVC/Clinoptilolite Ultrafiltration Nanocomposite Membranes

AbstractNovel polyvinyl chloride (PVC)/clinoptilolite nanocomposite membranes for water treatment were fabricated by non‐solvent‐induced phase separation and characterized with respect to their hydrophilicity, porosity, surface roughness, thermal stability, and surface and cross‐sectional morphology. All prepared membranes were evaluated in a submerged system for the removal of humic acid (HA) under various vacuum transmembrane pressure (TMP) conditions. The hydrophilicity, porosity, and thermal stability of the membranes were increased by the addition of 0.5 wt % clinoptilolite nanoparticles. A larger macrovoid appeared when clinoptilolite nanoparticles were added to the PVC membrane. Higher TMP leads to serious fouling and the formation of a thicker foulant layer on the membrane surface as well as less removal of HA.

Fabrication of polymeric nanocomposite forward osmosis membranes for water desalination—A review

Osmosis has started discovering technical application in the developing membrane technologies like Forward Osmosis and Pressure-Retarded Osmosis. It is the natural motion of solvent through a semi-permeable membrane caused by a highly concentrated solute gradient. Such technologies use thin-film membranes supported by porous layers and scalable membrane materials which open the door to new generation membrane developments. Membrane fabrication has a strong connection with the membrane surface properties and performance such as pore structure, hydrophilicity, surface roughness and water flux. This article provides a perspective on the current efforts in membrane fabrication and application of nanocomposite membranes for water treatment. Thin-film nanocomposite membranes have been employed to tailor membrane with enhanced selectivity, permeability, internal concentration polarization, fouling and stability. The main focus of this review is on how membrane science and emerging nanomaterials have been applied for forward osmosis desalination and water purification to meet the increasing worldwide demands for water.

2D Material Based Thin‐Film Nanocomposite Membranes for Water Treatment

AbstractMembrane‐based separation technologies are essential in the fields of desalination and wastewater treatment. 2D material based thin‐film nanocomposite (2D‐M‐TFN) membranes are emerging technology that combines 2D nanomaterials and conventional thin‐film composite membranes. It has great potential to further improve the efficiency of the membrane separation process. Although extensive studies are reported, 2D‐M‐TFN membranes for water treatment are not systemically reviewed. This work gives an intensive summary of this emerging technology. The function, mechanisms, and common characteristics of various 2D materials in the 2D‐M‐TFN membrane are first summarized and compared. An in‐depth discussion of different types of 2D‐M‐TFN membranes is then conducted, followed by the discussions on the challenges and opportunities.

Inorganic nanomaterials in polymeric water decontamination membranes

One of the major research challenges today is the efficient treatment and desalination of seawater, brackish water, and wastewater to make it recyclable and ecofriendly. Membrane technology has offered an increasingly important role to overcome confronts associated with the water treatment. Polymeric membrane is the most common and preliminary technology used for water purification. However, solicitation of polymeric membrane is restricted due to inadequate permeability, selectivity, strength, and low fouling resistance. Consequently, polymeric nanocomposite has emerged as a promising solution to address these flouts. Nanocomposite membrane is considered as a new class of membranes prepared by combining polymeric materials with nanoparticles. Advanced nanocomposite membranes based on polymer/inorganic nanoparticle materials have been designed to meet explicit water treatment applications. This review basically summarizes scientific and technological advances toward the development of polymer/inorganic nanoparticle nanocomposite membranes for water treatment. A wide range of inorganic nanoparticles have been used to reinforce polymers such as metal and metal oxide nanoparticle, nanoclay, and zeolite. Polymer/inorganic nanoparticle nanocomposite membranes have been fabricated by fine tuning the structure and physicochemical properties such as porosity, hydrophilicity, antibacterial, thermal, and mechanical characteristics. Moreover, inorganic nanoparticle incorporated in matrix may behave as adsorbents for the removal of toxic metal ions, inorganic, organic, and biological micropollutant, and other noxious compounds from aqueous solutions. Toward the end, challenges and future research trends on high-performance polymer/inorganic nanoparticle nanocomposite membranes have been discussed.

Novel nanocomposite polyethersulfone- antimony tin oxide membrane with enhanced thermal, electrical and antifouling properties

Application of organic−inorganic nanocomposite membranes for water treatment is exceptionally growing owing to their tunable functionalities in addition to their enhanced permeation and antifouling propensity. In the present work, novel nanocomposite polyethersulfone (PES) membrane was synthesized using antimony-doped tin oxide (ATO) nanoparticles (NPs) via phase separation technique. It was found that the modified PES-ATO nanocomposite membranes exhibited significantly higher fouling resistance and larger permeate flux recovery ratio when tested with oil sands produced water than unmodified PES membranes. Furthermore, the PES-ATO membranes provided 40% more organic matter removal compared to the base PES membranes. However, the addition of the ATO NPs to the PES casting solution resulted in tighter membranes with denser skin layer and lower average pore size. By evaluation of the surface potential and wettability of the membrane, it was revealed that the higher antifouling propensity and larger separation efficiency of the nanocomposite membrane originate primarily from their higher surface hydrophilicity and lower porosity which resulted in about 99% flux recovery during the filtration of oil sands produced water. Furthermore, the developed PES-ATO nanocomposite membranes demonstrated larger electrical conductivity and higher thermal stability compared to pristine PES membranes. The tunable antifouling propensity along with enhanced thermal stability and electrical conductivity suggest the promising potential of the developed PES-ATO nanocomposite membrane to be employed in advanced membrane technologies using external stimuli such as electric field, or thermal gradient for the purification of industrial produced water.

Progress of Nanocomposite Membranes for Water Treatment.

The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

A Comprehensive Review on Polymeric Nano-Composite Membranes for Water Treatment

During last few decades, membrane technology has emerged as an efficient technique over conventional methods due to its high removal capacity, ease in operation and cost effectiveness for wastewater treatment and production of clean water. Membrane based separations are commonly based on polymeric membranes because of their higher flexibility, easily pore forming mechanism, low cost and smaller space for installation as compared to inorganic membranes. Commonly employed membrane fabrication phase inversion method has been shortly reviewed in this article. Major limitation of membrane based separations is fouling and polymeric membranes being hydrophobic in nature are more prone to fouling. Fouling is a deposition of various colloidal particles, macromolecules (polysaccharides, proteins), salts etc. on membrane surface and within pores thus impedes membrane performance, reduces flux and results in high cost. Modification of polymeric membranes due to its tailoring ability with nanomaterials such as metal based and carbon based results in polymeric nano-composite membranes with high antifouling characteristics. Nanomaterials impart high selectivity, permeability, hydrophilicity, thermal stability, mechanical strength, and antibacterial properties to polymeric membranes via blending, coating etc. modification methods. Characterization techniques has also discussed in later section for studying morphological properties and performance of polymer nano-composite membranes. Graphical Abstract

Fabrication of antifouling and antibacterial polyethersulfone (PES)/cellulose nanocrystals (CNC) nanocomposite membranes

In this study, cellulose nanocrystals (CNC) were incorporated into polyethersulfone (PES) ultrafiltration membranes to improve their selectivity for separation of protein from water, as well as antifouling properties. PES/CNC nanocomposite membranes were prepared with non-solvent induced phase inversion technique. The effect of CNC loading in the PES on membrane morphology and performance was investigated. The contact angle and water content measurements revealed that the hydrophilicity of PES/CNC membranes enhanced by increasing the CNC content in the casting solution. The pure water flux was increased by introducing 1.0wt% CNC in the casting solution, while the further addition of CNC has decreased the water flux. The synthesized membranes were used for the removal of protein, bovine serum albumin (BSA), from the water. The BSA rejection ratio increased from 93% to 97% by adding 5.0wt% CNC into the PES. The flux recovery ratio (FRR) experiments showed significant improvement in the antifouling property of PES/CNC nanocomposite membranes. This study provides valuable insight into the preparation of high-performance nanocomposite membranes for water treatment by blending advanced nanomaterials with polymers. After conditioning by polyhydroxyamines (PAH), the PES/CNC membranes obtained high antibacterial property to gram-positive bacteria Staphylococcus aureus, indicated by the apparent halo zone around the membranes.

Highly stable MIL-101(Cr) doped water permeable thin film nanocomposite membranes for water treatment

Highly stable water permeable thin film MIL-101(Cr) nanocomposite membranes for water treatment were created via in situ interfacial polymerization.

Surface modification route to prepare novel polyamide@NH2_MIL-88B nanocomposite membranes for water treatment

A surface modification route is used to fabricate a novel PA nanocomposite membrane with a PA coating on a NH2_MIL-88B interlayer.

Biopolymers-based nanocomposites: Membranes from propionated lignin and cellulose for water purification

Nanocomposite membranes for water treatment were prepared by vapor-induced phase separation method from propionated lignin and cellulose triacetate (CTA). Three kinds of lignin were used: Kraft, Organosolv and Hydrolytic, which were propionated for improving their compatibility with CTA. Such chemical lignin modification was analyzed by FTIR, UV spectrophotometry and GPC. Morphology (through FE-SEM and AFM), mechanical properties (DMA), and surface potential (SPKM) were investigated for all membranes obtained. For determining membrane performance, groundwater from Chihuahua (Mexico) containing high concentrations of fluoride, arsenic, calcium, sodium and magnesium, was filtrated. Membrane rejection was 15–35% for anions present, and 12–42% and 27–54% for monovalent and divalent cations, respectively. Arsenic and fluoride removal by membranes was found to be affected by ionic and organic matter present in groundwater.