Superior forward osmosis cellulosic membrane for water desalination and brine concentration

Abstract

Abstract Brine is an inevitable product of desalination plants and various industrial sectors. The appropriate disposal of brines and their highly concentrated salts and other diverse contaminants is a critical environmental challenge to most plants. Recently, the FO process is gaining attention as a viable alternative to conventional brine concentration methods, primarily due to its reduced energy consumption. This study aimed to fabricate a high-performance nonwoven FO membrane from cellulose acetate (CA) blended with polysulfone (PS) via the phase inversion technique. The prepared membrane was investigated in both saline water desalination and brine concentration. The FO membrane performance was tested for saline water desalination at different NaCl concentrations and applied in brine concentration using two kinds of draw solutions: ammonium bicarbonate (NH4HCO3) and a mixture of ammonium hydroxide/ammonium bicarbonate (NH4 OH)/(NH4HCO3) at different concentrations. It was observed that a high flux of 150 LMH was attained by using 2 M NaCl as a draw solution against distillate water as a feed solution. For brine concentration, by application of (NH4 OH)/(NH4HCO3) draw solution mixture at a 1:1 ratio, the modified cellulosic FO membrane exhibited the highest water flux of 113 LMH.