Preparation of PSf-g-BN15C5/NWF composite membrane with sponge-like pore structure for lithium isotopes adsorptive separation

Polysulfone-graft-monoazabenzo-15-crown-5 ether (PSf-g-BN15C5) was synthesized via nucleophilic substitution reaction and used to prepare PSf-g-BN15C5/non-woven fabrics (NWF) composite membrane for lithium isotopes adsorptive separation by non-induced phase separation (NIPS). The influences of polymer concentration, additive and coagulation bath temperature on membrane properties were systematically explored. A solid-liquid dynamic extraction method was employed to investigate the lithium isotopes separation of the composite membrane. Results showed that the PSf-g-BN15C5/NWF composite membrane with a sponge-like pore structure, the porosity of 69% and the pure water flux of 1433 L/m(2)/h were obtained under the conditions: PSf-g-BN15C5 polymer concentration of 14 wt%, DMF as solvent and water as a non-solvent in coagulation bath at 60 degrees C. Moreover, it was found that the lithium isotopes equilibrium separation factor obtained from the membrane with immobilization amount (I-A) of 0.81 mmol/g was up to 1.052 +/- 0.002, which was much higher than that obtained from the traditional liquid-liquid extraction system of H2O-Lil/BN15C5-CHCl3 (1.007 +/- 0.002) and the solid-liquid static extraction using PSf-g-BN15C5 polymer (1.014 +/- 0.002) as extractant. In brief, the composite membrane has a great potential application in the development of a green-friendly adsorptive separation method for lithium isotopes. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.