Photocatalytic degradation of Estrone and Congo red by the magnetic antibacterial photocatalyst g-C3N4/CeO2/M-rGO under visible light and optimization by Box-Behnken statistical design (BBD)

Abstract

Construction of multi-interface contact step-scheme photocatalyst is a promising pathway to achieve high-electron transfer efficiency for photodegradation Estrone and Congo red (CR). In this work, g-C3N4 was selected as the main component, CeO2 nanosheets with unique Ce4+→Ce3+ conversion property and M-rGO were loaded on the surface of g-C3N4 to construct magnetic photocatalyst, whose structure imparted reusability by magnetic retrieval and at the same time M-rGO acted as an efficient host for g-C3N4/CeO2 composite photocatalyst. The photocatalytic performances were investigated with Estrone and CR, and the results showed that the composite photocatalyst g-C3N4/CeO2/M-rGO could degrade 71% of Estrone and 92% of CR. Free radical scavenger test showed that superoxide and hydroxyl radical species played a major role in the degradation. Furthermore, it was demonstrated that the magnetic photocatalyst g-C3N4/CeO2/M-rGO possessed strong antibacterial properties against Proteus mirabilis. A three-factor-three-level Box-Behnken design (BBD) was selected to optimize three greatly influential parameters: light irradiation time (min), the mass of photocatalyst (mg) and pollution concentration (ppm) by responding surface methodology. It was expected that the g-C3N4/CeO2/M-rGO can be used as a magnetic photocatalyst to achieve its valorization, which has very broad development prospects in the field of environmental remediation or catalysis.