Grafted Anion-Exchange Membranes Based on Radiation-Irradiated Fluorinated Films for Electrodialysis

Anion-exchange membranes were synthesized via radiation-induced graft polymerization of vinylbenzyl chloride or styrene (with subsequent chloromethylation) onto polyvinylidene fluoride and poly(ethylene-tetrafluoroethylene) films. The introduction of quaternary ammonium functional groups into the grafted polymer structure was carried out by treatment with a trimethylamine solution. The use of various preparation methods allows tuning the ionic conductivity in the range from 0.2 to 15.2 mS/cm and the potentiometric anion transport numbers in the range from 0.84 to 0.95. The possibility of using such membranes in ion separation by electrodialysis was demonstrated for the first time. The selectivity coefficients of the obtained membranes for the transport of monovalent ions relative to divalent ones reach 1.75 and 2.27 for the $${\text{C}}{{\text{l}}^ - }{\text{/SO}}_4^{2 - }$$ and $${\text{NO}}_3^ - {\text{/SO}}_4^{2 - }$$ pairs, respectively.