Study of pervaporation for dehydration of caprolactam through PVA/nano silica composite membranes

We investigated nano silica/PVA composite membranes to propose an improved caprolactam pervaporation (PV) dehydration process. The membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and contact angle measurement. Compared with the pure PVA membranes, the nano silica/PVA composite membranes showed different surface morphologies with enhanced hydrophilicity because of their unique formation. To evaluate PV performance and mechanism, we assessed the permeation flux, separation factor, diffusivity/sorptivity selectivity, and activation energy of the composite membranes. The evaluated results indicate that the nano silica/PVA composite membranes induced a breakthrough in the dehydration of a caprolactam-water mixture with a maximum flux of 3.8 kg m− 2 h− 1 and an acceptable separation factor of 150.

► We used nano silica/PVA composite membranes in caprolactam PV dehydration process. ► We achieved maximum flux on the industrial applications level (3.8 kg/m2h). ► Diffusivity /sorptivity selectivity were evaluated. ► We clarified the contribution of intrinsic membrane properties on PV performance.