Synthesis of thin-film composite forward osmosis membranes for removing organic micro-pollutants from aqueous solutions

In this study, a thin-film composite (TFC) forward osmosis membrane was synthesized and characterized with various concentrations (15%, 16%, 17% and 18%) of polysulfone for the removal of two organic micro-pollutants, namely phenol and benzene from the aqueous solutions. Synthesis of a thin-film composite membrane with a support layer carried out by dissolving an amount of polysulfone polymer and polyvinyl pyrrolidone in N-methyl,2-pyrrolidone via phase inversion process and a thin-film layer of the polyamide M-phenylenediamine (MPD) and 1,3,5-benzene trichloride by interfacial polymerization reaction for the fabrication of the TFC were examined. Water flux and reverse salt flux decreased with increasing the concentration of polysulfone polymer. The composite membranes with polysulfone at 16% and 17% had even higher efficiencies. Also, by increasing the concentration of the draw solution, further phenol and benzene could be removed. The highest rejection rates of phenol (polar) and benzene (nonpolar) were found to be 79% and 90%, respectively. The results showed the capability of the thin-film composite forward osmosis (TFC-FO) membranes for removing organic micro-pollutants from the aqueous solutions under different operating conditions, with the efficiency of removing nonpolar compounds being higher.