Visible light-driven photocatalytic degradation of rhodamine B and 5-fluorouracil using ZIF-8/GO: unveiling mechanisms

Abstract

The removal of pharmaceutical and organic contaminants from wastewater remains a pressing challenge for conventional treatment technologies. In this study, a novel photocatalyst composed of Zeolitic Imidazolate Framework-8 (ZIF-8) nanocrystals integrated with a graphene oxide (GO) matrix was developed via a facile interfacial synthesis approach. The structural and morphological properties of the resulting ZIF-8/GO composite were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The composite's photocatalytic efficiency was assessed through the degradation of Rhodamine B (Rho-B), a representative dye pollutant, and 5-fluorouracil (5-Flu), a widely used pharmaceutical, under visible light irradiation. The ZIF-8/GO catalyst achieved near-complete degradation of Rho-B (100%) and 5-Flu (97.4%) within 100 minutes. This high performance is attributed to the synergistic effects of ZIF-8 and GO, which enhance surface area, improve light absorption, and promote charge separation. Moreover, the catalyst retained considerable activity over five cycles, with only a 12.8% decrease in Rho-B degradation due to minor material loss. The findings demonstrate that the ZIF-8/GO composite is a highly efficient, recyclable, and sustainable photocatalyst, showing great promise for the removal of complex pollutants from wastewater and contributing to environmentally friendly water purification technologies.