Plasma Modified Track-Etched Membranes for Separation of Alkaline Ions

摘要

Poly(acrylic acid) and copolymers of acrylic acid and di(ethylene glycol)methyl ether methacrylate were grafted onto polycarbonate and poly(ethylene terephthalate) membranes using dielectric barrier discharge plasma. The obtained membranes exhibited responses to pH change. When they were porous, they behaved as pH-sensitive valves. When pores were filled with gel, they were able to work in dialysis and separated LiCl, KCl, and NaCl salts. The best selectivity for alkaline ions was obtained for poly(ethylene terephthalate) membranes grafted onto copolymer of acrylic acid and di(ethylene glycol)methyl ether methacrylate with a grafting yield of 0.16 mg/cm². The separation should be conducted at pH = 5.5. It was noted that there is better membrane selectivity towards lithium and potassium than sodium ions.