Hydrophilic ZSM-5 membrane for forward osmosis operation

A potential of zeolite membrane in forward osmosis operation was investigated for the first time. A hydrophilic zeolite, ZSM-5, membrane was prepared on an α-alumina tubular support by a secondary growth method. NaCl aqueous solution and distilled water were used as draw and feed solutions, respectively. The membrane exhibited a water flux of 2.2 L m⁻² h⁻¹ with a salt flux of 0.69 g m⁻² h⁻¹ at 313 K by using 9.0 wt% draw solution. ZSM-5 membrane showed a quite small reverse salt flux based on a molecular sieving effect in the relatively wide temperature ranges of 298–333 K. ZSM-5 membrane also kept its performance under acidic conditions. In addition, obvious deterioration of the membrane performance was not observed after intermittent use of our membrane for more than one month.