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A B S T R A C TEven though nanofiber membranes have wide unique characteristics, such as high surface porosity, high flux ratios, and lower production costs, they still show some shortcomings in terms of irreversible clogging, large pore sizes, and nanofiber rupture during filtration. This paper addresses a study to overcome such limitations with simultaneous electrospinning technique. Two different types of nanofibers were collected on the same layer. Polyacrylonitrile (PAN) nanofiber membranes have lower pore size than polysulfone (PSU) nanofiber membranes, while PSU component allowed easier toughening since it requires lower temperature for mechanical improvement against fiber rupture. As a result, pore size of simultaneous nanofiber membranes was provided by PAN (around 0.8 μm), whereas heat treatment at 185˚C improved the strength of nanofiber membranes against rupture during filtration. Wastewater and surface water were filtered for filtration characterization. For both, removal rates were great. Thermal treatment improved membranes against fiber rupture. While fibers of heat-treated membrane were not broken, non-heat-treated membranes' fibers were broken and membrane disintegrated. But significant irreversible fouling was observed in wastewater filtration.

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Polyacrylonitrile (PAN) is a hydrophilic polymer with good chemical resistance, low price, and excellent processability for fabricating membranes, especially for electrospun nanofiber-based membranes. In this review, the recent developments in the application and modification of PAN membranes are discussed, focusing on some applications such as pervaporation (PV), ion exchange, hemodialysis, membrane distillation, adsorption membrane, and water and wastewater treatment. First, the physicochemical characteristics and the synthesis techniques of the PAN are discussed, and next, the PAN application in the fabrication of membrane is reviewed. Different PAN membranes with their fabrication techniques are reviewed with detailed studies focused on the modification methods. By using different modifiers especially nanomaterial blending, the physicochemical properties and performance (membrane structure, permeability, mechanical strength, hydrophilicity, porosity, and surface charge) of the PAN membranes are improved. Finally, the challenges and future perspective of these membranes are discussed. The review of research progress in this paper may provide an insight into the development of high-performance PAN membranes and spread the applications of PAN membranes in different separation processes in the future.

In the present study, polyvinyl chloride (PVC) membranes were used to improve water purification and fouling performance. Porous PVC flat sheet membranes were produced using the phase inversion method. The polymer concentration in casting solution varied from 11 to 17 wt%. Water contact angles, pore size, overall porosity and scanning electron microscopy were used for membrane characterization. The foulants such as bovine serum albumin (BSA) and humic acid (HA) were used to test the membranes' separation performance and fouling resistance. Contact angle increased from 79.6 ± 2.2° to 81.9 ± 1.0° as the polymer concentration increased, while overall porosity decreased from 72.0% to 61.9%. Results showed that BSA and HA permeate flux had similar trend by adding PVC. It was observed that BSA rejection enhanced from 54.8% to 80.7% while HA rejection increased from 76.3% to 88.3% with increasing PVC content. Permeate flux decreased by increase of PVC content due to reduction of porosity and pore size. Besides, the flux recovery ratio, reversible and irreversible fouling studies showed that better fouling observed with increasing of PVC content. The findings of this work show that PVC may be used to improve the separation and antifouling properties for water purification.