Facile Preparation of Attapulgite-Supported Ag-AgCl Composite Photocatalysts for Enhanced Degradation of Tetracycline

In this study, Ag-AgCl/attapulgite (Ag-AgCl/ATP) composites were synthesized via a direct precipitation method using ATP nanorods as a catalyst supporter. ATP nanorods helped to increase the dispersion of Ag-AgCl particles and broaden the light absorption spectrum, which would also help to increase the active site of the catalyst to promote the degradation of tetracycline (TC). The photocatalytic activity of the Ag-AgCl/ATP composites was evaluated through the degradation of TC, identifying the loading amount of Ag-AgCl, the concentration of TC, and the reaction temperature as critical factors influencing activity. Specifically, the optimal conditions were observed when the loading of Ag-AgCl was 75%, resulting in a photocatalytic degradation efficiency of 77.65%. Furthermore, the highest degradation efficiency (85.01%) was achieved with a TC concentration of 20 mg/L at 20 °C. Radical trapping experiments suggested that the superoxide anion radical (·O2−) was the primary active species in the degradation process, although hydroxyl radicals (·OH) and holes (h+) also contributed. Reusability tests confirmed that the Ag-AgCl/ATP composites exhibited excellent stability and could be effectively reused.