Pervaporation performance of chitosan–poly(acrylic acid) polyelectrolyte complex membranes for dehydration of ethylene glycol aqueous solution

Polyelectrolyte complex membranes (PECM) composed of chitosan (CS) and poly(acrylic acid) (PAAc) were prepared by blending two polymer solutions with different ratios for pervaporative dehydration of ethylene glycol (EG) aqueous solution. The composition and morphology of CS–PAAc polyelectrolyte complex membrane were characterized by Fourier transform-infrared (FT-IR) and scanning electron microscope (SEM). The mechanical properties and thermal stability of the membrane were tested by universal testing machine and thermogravimetric analysis (TGA), respectively. Effects of PAAc content, EG concentration in the feed, operating temperature and feed flow rate on pervaporation performance of the membrane were systematically investigated. Among all the concerned membranes, PECM60/40 exhibited the highest separation performance with a H2O/EG separation factor of 105 and a flux of 216 g/m2 h at 70 °C for 80 wt% EG aqueous solution. With the increase of operating temperature and feed flow rate, permeation flux increased but separation factor decreased. With the increase of EG concentration in feed solution, the permeation of flux of water decreased, and the flux of EG first increased and then decreased while the separation factor firstly decreased sharply but then fluctuated around 80.