Preparation of K-doped g-C3N4 composite loaded on magnetic attapulgite and its degradation performance for malachite green

Abstract

Visible-light-driven photocatalysis is a promising technology for the treatment of dye wastewater. In this work, a novel photocatalyst of K-doped g-C₃N₄ loaded on magnetic attapulgite (ATP) (K_ω-g-C₃N₄@ATP-Fe₃O₄) with excellent visible light photocatalytic properties and stability were successfully prepared and characterized. The removal efficiency of K_ω-g-C₃N₄@ATP-Fe₃O₄ for malachite green (MG) was studied, and the degradation mechanism was analyzed and proposed. It was found that the K₅-g-C₃N₄@ATP-Fe₃O₄ photocatalyst possessed excellent degradation efficiency of over 98.0% for the MG dye wastewater under optimal conditions. Moreover, the K₅-g-C₃N₄@ATP-Fe₃O₄ materials possessed good recyclability with a removal rate over 82% after 4 cycles. Under visible light condition, the K₅-g-C₃N₄@ATP-Fe₃O₄ photocatalyst produce radicals of ·OH and $·O_2^{-}$ to degrade the MG dyes, which was supported by electron paramagnetic resonance (EPR) and radical trapping experiments. In addition, the LC-MS analysis interpreted the degradation pathways and intermediates of MG in the solution. The findings in this work indicate that the prepared photocatalytic material has excellent degradation efficiency for MG and can be applied in dye wastewater treatment.