Highly permeable nanofibrous composite microfiltration membranes for removal of nanoparticles and heavy metal ions

Nanofibrous composite membranes using polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) were fabricated by the two-nozzle electrospinning approach, where the PAN nanofibrous component was modified selectively, and the composite membranes were employed for removal of both nanoparticles and heavy metal ions such as chromium (VI) and cadmium (II) from contaminated water. The chemical compositions and morphologies of the membranes were determined by FTIR, TGA, elemental analysis, SEM, and porometer measurements. It can be seen that the two nanofibrous components were integrated together, where the PVA nanofibrous component was cross-linked by glutaraldehyde (GA) working as a mechanical support of the membrane, and the PAN nanofibrous component could be further functionalized independently. The PAN component was further modified by surface grafting or hydrolysis to fabricate composite microfiltration membranes which exhibited high separation efficiency and selectivity for particular sized-microspheres, while positively charged or negatively charged nature enabled impressive adsorption capability, as demonstrated by the removal of chromium (VI) and cadmium (II) ions from contaminated water, respectively.