Fabrication of biodegradable Polylactic Acid (PLA) membrane for reverse osmosis process

Abstract

Polylactic Acid (PLA) is a pronounced biodegradable polymer which has been developed to be used in a broad range of applications due to its biocompatibility and would be able to solve the problems suffered from commercial polymeric membrane used in reverse osmosis (RO). Asymmetric flat sheet PLA membrane were fabricated via phase inversion technique using non-solvent induced phase separation (NIPS). Different weight % ratio of ethanol and water as a coagulant bath medium (0:100, 20:80, 40:60, 80:20 and 100:0) were varied to investigate the effect of different membrane microstructure of the PLA membrane performance in reverse osmosis process. The prepared membranes were characterized through several characterizations and undergo the performance test using dead end filtration. Increasing ethanol contents resulted in higher porosity and lower contact angle due to forming of pores sparsely on the membrane surface. The morphologies of membrane top surface was strongly affected by the medium of coagulant bath. Two membranes fabricated using 40 wt,% and 80 wt.% ethanol as a coagulant bath were carried out with performance test. The findings revealing the highest water flux and permeability was shown by a membrane fabricated from 80 wt. % of ethanol and 20 wt. % of distilled water. It was also found that the respective membrane showed the highest salt rejection capability.