Solar photocatalytic abatement of tetracycline over phosphate oxoanion decorated Bi2WO6/polyimide composites

Environmental-friendly solar photocatalytic technology is attracting great attention in the field of pollution control. In this work, novel PO43−-Bi2WO6/PI photocatalyst achieved high degradation efficiency for tetracycline degradation in simulated solar light (1.6 times kinetic constants of Bi2WO6). The photocatalyst could produce more oxygen vacancies as well as more active species O2− and OH, and exhibited high mineralization ability, good stability and recyclability simultaneously. After 4 cycles of degradation experiments, its degradation efficiency was only reduced by 8.6 %. Tetracycline molecules gradually became small molecules under the attack of active species. The tetracycline degradation was highly pH-dependent and enhanced with the increase of solution pH. The water quality parameters humic acid and Cl− presented the inhibitory effect, while HCO3− can accelerate the tetracycline degradation. The degradation of tetracycline by PO43−-Bi2WO6/PI conformed to the Z-scheme photocatalysis mechanism, which could effectively broaden the absorption of solar light, improve the separation and transfer of photogenerated electron-hole pairs and extend the lifespan of the photocatalyst.