TiO2-Decorated Photocatalytic Nanofiltration Membranes for Enhanced Self-Cleaning and Separation Performance

Advanced nanofiltration (NF) processes have been extensively utilized to handle wastewater generated in the dyeing industry. However, NF membranes inevitably incur fouling issues during their operation procedure. Herein, TiO2 nanoparticles were employed as an additive in the aqueous phase in an interfacial polymerization (IP) process to fabricate the thin-film nanocomposite (TFN) NF membrane. With the introduction of TiO2 nanoparticles, a rougher and more hydrophilic membrane surface was obtained. The optimal TFN membrane with 1.5% TiO2 decoration exhibited a pure water permeability of up to 14.32 L m–2 h–1 bar–1, which was 1.88 times higher than that of the pristine thin-film composite membrane. Moreover, the obtained NF membrane maintained high rejections toward dye molecules (99.7% for Congo red, 99.5% for reactive blue 19, 99.7% for xylene brilliant cyanin G, and 99.1% for methyl blue), considerable salt rejections (44.5% for NaCl, 91.2% for Na2SO4, 54.1% for MgCl2, and 82.8% for MgSO4), and satisfactory stability during the 72 h long-term operation. The exceptional self-cleaning ability of resultant TFN membranes under UV irradiation offered an inspired method for establishing photocatalytic self-cleaning membrane to treat wastewater.