Pervaporation separation of MeOH/DMC mixtures using STA/CS hybrid membranes

Silicotungstic acid hydrate (STA)/CS hybrid membranes were prepared by filling STA into chitosan (CS) matrix. The membranes were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle meter. The results show that the hydrophilicity of the hybrid membrane increases, however, the crystallinity of the membrane decreases with STA content increasing. STA was well dispersed in the membrane when its content is less than 8 wt%. It is found that the swelling degree of the STA/CS hybrid membrane increases with increasing STA content or methanol (MeOH) content. The effects of STA content, feed MeOH content and feed temperature on pervaporation (PV) performance were also investigated. The results show that separation factor increased with STA content increasing and arrived at a maximum when the STA content is 8 wt%, while permeation flux increased with increasing STA content. The separation factor decreased with increasing the feed temperature or MeOH content, however, the flux increased with increasing the feed temperature or MeOH content. The membrane has remarkable separation performance with a flux of 1163 g m−2 h−1 and separation factor of 67.3 at 50 °C at the feed methanol content 10 wt%.