Polymeric PDI-based photocatalytic nanoarchitectures promoting the performance of thin film composite membrane for forward osmosis water purification

Exploring versatile membrane with photodegradation capability provides a promising approach to overcome the fouling dilemma of membrane technologies, while the utilization of photocatalysts in the realm of forward osmosis encounters challenges, primarily due to the propensity of the potent oxidizing species produced during photocatalysis to cause substantial harm to the delicate nano-selective layer present within forward osmosis membrane. In this study, we demonstrate a multi-functional polymeric membrane with good stability for water purification via forward osmosis separation. Organic perylene diimide supermolecule was employed to construct a heterostructured catalytic layer for abating the attached pollutants under visible light irradiation. The interfacial polymerization of polyamide layer on the other side of polyethersulfone substrates allows the selective separation function. The synergistic effect of catalytic layer and selective layer simultaneously improved the separation performance and anti-fouling capability, endowing the Janus membrane with a reduced reverse NaCl flux, 83% lower, and a suppressed membrane fouling, 81% lower than the original membrane. This work provides a new strategy for the design of multi-functional composite membrane for high-efficiency water purification.