High performance polyamide TFC reverse osmosis membrane fabricated on co-deposition hydrophilic modified polyethylene substrate

The separation performance of polyamide (PA) thin film composite (TFC) membrane is critically influenced by the substrates. Numerical models and experimental studies suggest that substrates with high porosity comprising small pores can effectively improve membrane performance. Here we report that a commercial polyethylene (PE) micro-porous membrane with high porosity was chosen as substrate for fabricating PA TFC membrane. The PE substrate was modified by co-depositing the copolymers of gallic acid and gamma-aminopropyltriethoxysilane to improve its bulk hydrophilicity. The porosity, pore size, morphology and chemical properties of the modified PE substrates were characterized. The resultant PA TFC-PE membrane had a favorable water permeance of 2.33 +/- 0.06 L m(-2) h(-1) bar(-1) as well as a high NaCl rejection of 99.0 +/- 0.4 % because of the suitable porosity, pore size and hydrophilicity for interfacial polymerization reaction. Our work is expected to provide an efficient way for the modification of hydrophobic porous membrane for fabricating PA TFC membrane.

Automated summary

The separation performance of polyamide thin film composite membrane is significantly affected by the choice of substrate. This study demonstrates that modifying a commercial polyethylene micro-porous membrane can improve the performance of a polyamide TFC membrane. The modified PE substrate showed favorable properties for interfacial polymerization reaction, resulting in a PA TFC-PE membrane with high water permeance and NaCl rejection.