A Ternary Composite Polysulfone Membrane with Photocatalytic, Superhydrophilic, and Antifouling Properties for Efficient Water Ultrafiltration

Polyoxometalates (POMs) have emerged as a promising modification material for high-performance membranes with increased hydrophilicity, permeability, and potential catalytic properties. In the present work, phosphotungstic acid was successfully modified onto the polysulfone-Al2O3 composite membrane through a simple surface modification method. The successful modification of POM was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle measurement. The membrane permeation performance toward rhodamine B was evaluated. An evident enhancement of both water flux and dye rejection was obtained. Moreover, the retained dye on the membrane surface could be easily degraded through photoirradiation owing to the photocatalytic activities of POM. The POM-modified membrane has a desirable regeneration ability for six repetition cycles. The antifouling performance was also investigated using humic acid aqueous solution under 1 bar. The POM-modified membrane exhibited the water flux 3.8 times higher than the unmodified membrane. Compared with the 23.8% flux recovery ratio (FRR) of the unmodified membrane, a 67.1% FRR of POM-modified membrane was attained. The enhanced water permeability, superhydrophilicity, and antifouling performance of an as-prepared membrane made it a promising candidate for wastewater purification.