An efficient photocatalyst coating strategy for intimately coupled photocatalysis and biodegradation (ICPB): Powder spraying method

Intimately coupled photocatalysis and biodegradation (ICPB) is an attractive wastewater treatment technology, and the key to a successful ICPB is a carrier capable of accumulating biofilm inside and adhering photocatalyst firmly on its exterior. However, the photocatalysts coated on the carrier by the conventional method not only occupy the internal pores which should be left for microorganism loading, but also possess an insufficient adhesion to the carrier. To solve this problem, a powder spraying method has been proposed for the first time, which allows the photocatalyst to adhere more firmly on the exterior surface of the carrier, and to reserve the inside pore structures for biofilm accumulation. In the end, when using visible-light-induced ICPB (called VPCB), the degradation rate of tetracycline hydrochloride achieved 97.2%, and the stability of recycled carrier was still excellent even after 6 cycles of operation. This work provides a novel avenue for the design of a highly stable ICPB system with low-cost and high degradation efficiency.