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

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) (Kω-g-C3N4@ATP-Fe3O4) with excellent visible light photocatalytic properties and stability were successfully prepared and characterized. The removal efficiency of Kω-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 ⋅O2− to degrade the MG dyes, which was supported by 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.