Membrane manufacturing via simultaneous electrospinning of PAN and PSU solutions

Abstract

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.

Solvent vapor treatment improves mechanical strength of electrospun polyvinyl alcohol nanofibers

“…Recent studies have focused on using this technique for various applications, such as with affinity membranes, for drug release, tissue scaffolds, sensors, as protective clothing agents, and in the fields of energy, electronic devices, and composite reinforcement [ 1 , 2 , 3 , 4 , 5 , 6 ], mainly because of the remarkable properties of electrospun nanofibers, such as a small diameter, high aspect ratio, large specific surface area, and unique physical and chemical properties [7] . The polymers commonly used for fabricating the electrospun nanofiber membrane are polyvinylidene fluoride (PVDF) [8] , polysulfone (PSU) [9] , polyacrylonitrile (PAN) [10] , polyethersulfone [11] , polyamide (PA) [12] , and polyvinyl alcohol (PVA) [ 13 , 14 , 15 , 16 ].…”

Methods in Improving the Mechanical Properties and Flux of Nanofibre Membranes for Water Filtration

“…To endure operational circumstances, pressure-driven membrane filtering technologies require an appropriate mechanical strength [33,34]. There are many ways to increase mechanical properties of nanofibre mebranes, such as post treatment, which include solvent vapour [27,29,35,36], chemical crosslinking [14.45], hot pressing, annealing [31,48,49,50,51,52,53], hot stretching, and stretching/drawing (Figure 2). The treatment of nanofibre membranes using solvent vapour is preferable as the nanoscale phase separation is more organised and it has a better thermodynamic stable morphology of the active layer [27,36].…”

“…Heat treatment was also investigated in other studies [31,49,50,51,53]. Although heat treatment was seen to increase tensile strength in all of these studies [31,49,50,51,53], some studies show a decrease in elongation at break [50,51,52,53]. The tensile strength was increased due to the fibre fusing with one another.…”

Electrospun Silver Coated Polyacrylonitrile Membranes for Water Filtration Applications

“…PAN has excellent properties, including high mechanical properties, a unique thermal stability, and an ability to undergo pre-spinning and post-spinning modifications [ 2 , 3 , 4 , 5 , 6 , 9 , 12 , 13 , 14 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Furthermore, PAN porous membranes produced using various processing techniques have been widely investigated for water filtration applications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 29 , 30 ]. Compared to other conventional processing techniques, electrospinning has obtained tremendous interest among researchers as the process is simple, reproducible, cost-effective, and scalable for the development of porous membranes for water filtration and treatment […”

“…Furthermore, PAN porous membranes produced using various processing techniques have been widely investigated for water filtration applications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 29 , 30 ]. Compared to other conventional processing techniques, electrospinning has obtained tremendous interest among researchers as the process is simple, reproducible, cost-effective, and scalable for the development of porous membranes for water filtration and treatment [ 2 , 3 , 4 , 5 , 7 , 8 , 10 , 11 , 15 , 18 , 19 , 20 , 26 , 27 , 28 , 29 ]. Additionally, PAN membranes fabricated using electrospinning can be functionalized using various chemicals to make them anti-bacterial and anti-microbial [ 1 , 4 , 5 , 7 , 8 , 9 ,…”