Enhanced antifouling and antimicrobial thin film nanocomposite membranes with incorporation of Palygorskite/titanium dioxide hybrid material.

Palygorskite (Pal) is a kind of low-cost and environment-friendly natural nanoclay material with tubular structure and excellent hydrophilicity. TiO2 nanoparticles, especially anatase phase, have prominent photocatalytic bactericidal and organic pollutant decomposition activities. In this work, Pal and Pal/TiO2 nanocomposite were successfully embedded in the polyamide (PA) selective layer of the reverse osmosis (RO) membranes via interfacial polymerization. The tubular structure of Pal possesses a cross-sectional area of 0.37 × 0.63 nm2, which facilitates the selective transport of water molecules through PA layers. The water flux of Pal incorporated TFN membrane increases to approximately 40 l·m-2·h-1 at 16 bar, which is 1.6-fold higher than the reference TFC membrane. Meanwhile, the NaCl rejection is maintained at approximately 98%. Although the Pal/TiO2 incorporated TFN membrane exhibited slightly lower flux (1.4-fold higher than TFC), the embedded Pal/TiO2 contributed to the antifouling and photocatalytic bactericidal capacities and the salt rejection maintained at an acceptable level of 98%, which are greatly desired in the membrane desalination and water reclamation processes.