Separation of caprolactam–water system by pervaporation through crosslinked PVA membranes

ɛ-Caprolactam (CPL) is usually crystallized from CPL–water mixtures by reduced pressure distillation through triple-effect evaporation sets. But high energy consumption and low heat transfer coefficient limit economic profit of this process. To improve or substitute the CPL aqueous solution dehydration process, pervaporation separation of caprolactam–water system was investigated using PVA crosslinked membranes. An in-depth study of sorption, swelling, pervaporation performances of caprolactam–water mixtures and crosslinked membrane had been conducted. The experimental data demonstrated that the PVA crosslinked with glutaraldehyde showed excellent dehydration performances. The novel separation technique is feasible for application to the dehydration of CPL–water mixtures.