Ag3PO4/g-C3N4 Z-scheme composites with enhanced visible-light-driven disinfection and organic pollutants degradation: Uncovering the mechanism

Abstract

A novel Z-scheme Ag3PO4/g-C3N4 heterostructures was constructed successfully for Escherichia coli inactivation and organic pollutants degradation under visible light irradiation. The Ag3PO4(8)/g-C3N4 possessed the highest photocatalytic effect with more than 7 log of live Escherichia coli (E. coli) totally inactivated within 75 min and complete BPA degradation within 180 min. By mimicking the components of natural water individually, humic acid (HA) and inorganic anion were found to deeply affected the photocatalytic disinfection activity. Moreover, the Ag3PO4(8)/g-C3N4 revealed significantly boosted visible-light-driven photocatalytic performance for ciprofloxacin and sulfadiazine degradation. The satisfying degradation effects of bisphenol A in nature waters were also obtained. The improved photocatalytic efficiency of Ag3PO4/g-C3N4 may be attributed to the formation of Z-scheme heterostructure structure and matching valence band and conduction band, resulting in rapid separation of photo-induced carrier, enhanced electronic transport capacity and prolonged carrier lifetime. The possible mechanism was studied using radical quenching tests and electron spin resonance, suggesting that the hole, electron and hydroxyl radical were the paramount active species during Escherichia coli disinfection. This work pioneers a novel strategy for upgrading the photocatalytic disinfection and degradation capacities of g-C3N4 based catalysts.