Integrating K and P co-doped g-CN with ZnFeO and graphene oxide for S-scheme-based enhanced adsorption coupled photocatalytic real wastewater treatment.

Recently, there has been a significant increase in the interest of using photocatalysis for environmental clean-up applications. In this research, potassium, and phosphorus co-doped graphitic carbon nitride (KPCN) photocatalyst modified with graphene oxide (GO) and heterostructured with ZnFeO was synthesized via the hydrothermal method (KPCN/GO/ZnFeO). The photoactivity of KPCN/GO/ZnFeO photocatalyst was examined for the photocatalytic degradation of target pollutants such as methylene blue (MB) dye, rhodamine B (RhB) dye, and tetracycline (TC) antibiotic. Furthermore, the chemical oxygen demand (COD) removal efficiency for real wastewater was determined to explore the practical application of KPCN/GO/ZnFeO photocatalyst. The degradation efficiencies of bare graphitic carbon nitride, KPCN, KPCN/GO, and KPCN/GO/ZnFeO photocatalysts for tetracycline antibiotics were 30%, 42%, 57%, and 87% within 60 min, respectively. Moreover, KPCN/GO/ZnFeO photocatalyst showed 71% COD removal efficiency within 240 min. The OH and O were the major reactive species in the photocatalytic process. Results showed that the degradation efficiencies of graphitic carbon nitride were greatly enhanced upon doping and further improved with the addition of GO and ZnFeO. Doping improved light harvesting, GO enhanced the adsorption ability and heterojunction with ZnFeO enhanced the charge separation as well as the reusability of synthesized KPCN/GO/ZnFeO photocatalyst.