Cation exchange membranes from hot-pressed electrospun sulfonated poly(phenylene oxide) nanofibers for alkali recovery

Cation exchange membranes (CEMs) have been prepared from sulfonated poly(phenylene oxide) (SPPO) by electrospinning and hot-press treatment. Effect of various parameters, such as concentration, voltage and tip to collector distance (TCD) as well as the hot-press treatment conditions on properties of membrane has been fully investigated. When being applied in diffusion dialysis (DD) for alkali recovery from Na2WO4/NaOH solution, the membrane exhibits higher hydroxide permeability (UOH, 0.00971 m/h) and separation factor (S, 36.09) than the solution casting SPPO membrane (CSPPO), of which UOH is only 0.00605 m/h and S is 21.8. Compared with previously reported DD membranes with UOH in the range of 0.0014-0.0022 m/h, Hot-pressed Electrospun SPPO (H-ESPPO) shows approx. 4 times higher in UOH, underling its superior performance in DD application.