Preparation of non-woven supported ECTFE membrane by cast-coating method for membrane distillation

Abstract

This work presents a novel preparation method, based on cast-coating, of a non-woven supported low melting point (LMP) poly (ethylene chlorotrifluoroethylene) (ECTFE) (Halar®) membrane. In particular, a LMP ECTFE dope solution was prepared via thermally induced phase separation (TIPS) method. Diethyl adipate(DEA) was used as solvent and diethylene glycol (DEG) was used as coagulation bath. Three types of non-woven material were used as support and the prepared membranes were characterized by SEM, pore size, porosity, contact angle, etc. Suitable membranes were selected and tested in pure water membrane distillation (MD) process, and also in 0.6 M NaCl solution to assess the recovery ability of the membrane. These prepared membranes were also compared with a commercial polypropylene (PP) membrane in terms of MD performance. The membranes showed a flux from 5 to 7 L/m2 h at the feed temperature of 55 °C and the salt rejection was above 99.9% when 0.6 M NaCl solution was used as feed, thus indicating them as promising candidates for the MD process.