Abstract

Membrane separation is the most widely used technologyin desalinationto produce drinking water that requires improved permeability andsalt rejection. The objective of the present study is to modify fullyaromatic polyamide (NF90) and semiaromatic poly(piperazine-amide)(NF270) nanofiltration membranes via interpenetrating polymer networksof [3-(acryloyl-amino)propyl]trimethyl-ammonium chloride(ClAPTA), 2-acrylamide-2-methyl-1-propane-sulfonic acid (APSA),and glycidyl methacrylate-N-methyl-d-glucamine (GMA-NMG). The surface topography of the modified NF270and NF90 membranes was analyzed by SEM and AFM. The modified NF270membrane showed more significant roughness changes than the original(39%), while the modified NF90 membrane showed slight changes (7%).The FTIR results showed the chemical modifications introduced in themembranes. The best modified NF90 membrane (0.13 M GMA-NMG-0.07 MAPSA) showed an 84.3% and 0.6% increase in water flux and chloriderejection for filtration of a model solution, respectively, comparedto the commercial membrane. Furthermore, the best membrane modificationwas achieved with P(ClAPTA-co-GMA-NMG), increasingseawater permeability by 300% without modifying the high rejectionsof the original membranes. This work provides a guide to improvingthe permeability of NF membranes without sacrificing a higher speciesrejection by modification with interpenetrating polymers.