Study of solvent casting/particulate leaching technique membranes in pervaporation for dehydration of caprolactam

New porous and rough PVA (polyvinyl alcohol) membranes were synthesized by solvent casting/particulate leaching technique to improve caprolactam (CPL) pervaporation (PV) separation dehydration process. The membranes were characterized by FTIR, SEM, XRD, and contact angle measurements. On account of their special structure, solvent casting/particulate leaching technique membranes showed different surface morphologies compared with the original PVA membrane with enhanced hydrophilicity. By evaluating PV performance and mechanism, a PV transport equation was introduced to evaluate composite membrane permeation flux, separation factor, diffusivity/sorptivity selectivity, and activation energy. The maximum flux obtained in this work was greatly improved to 3.2 kg/m2 h and reached industrial application levels for separating CPL/water mixtures (CPL 70 wt%).