Abstract:
The severity of risks caused by arsenic and selenium ions in aqueous environments are
well-known. Novel thin film block copolymer based nanocomposite membranes are
synthesized for an efficient removal of these toxic ions. Nexar, a commercially available
amphiphilic sulfonated pentablock copolymer creates a self-ordering and a long range
nano morphology. The resultant morphologies thus creating nano-highways helps in
improving the flux through the resultant membranes. The effect of fouling in the
membranes are countered by using octaphenyl-POSS as the nanofiller. The second phase
of work aims at surface modification of Polyether imide nanofiltration membranes with
enhanced separation for arsenic and selenium. Specifically, a zwitterionic copolymer
comprising MPC and AEMA is synthesized via a one-pot free-radical polymerization.
Different amounts of MPC and AEMA monomers were introduced at molar ratios of 5:5,
7:3, and 9:1 to tune the physicochemical properties of the newly developed copolymer
and the effect on the filtration performance of these varied molar ratios of the monomers
is kept under check. Comparative analysis was done based on results obtained from both
works. Membranes modified with zwitterionic materials imparted their hydrophilic
properties to the membranes with the WCA as low as 22o were observed for copolymers
with molar ratio 7:3(MPC: AEMA). Whereas for the Nexar membranes with POSS
incorporated the WCA were not as low. Based on the rejections, the membranes were also
compared with the copolymeric membranes modified with water and TEA showing
superior results than its counterpart as well as those with POSS incorporated Nexar
membranes with rejection of 99.49% and 98.78% for arsenic and selenium respectively
