Cu-S codoping TiO2/SiO2 and TiO2/SiO2/Fe3O4 core-shell nanocomposites as a novel purple LED illumination active photocatalyst for degradation of diclofenac: the effect of different scavenger agents and optimization

Abstract

Cu-S co-doped TiO2/SiO2 as a novel photocatalyst which is active in visible light was synthesized by simple so-gel method. Also, Fe3O4 nanoparticles were used as the core to create a magnetically separable photocatalyst. The prepared samples were characterized by XRD, BET, BJH, DRS-UV/Vis, PL, FESEM, EDX, TEM, XPS, and VSM analysis. The photocatalytic effect of synthesized samples was examined on diclofenac (as a model hazardous contaminant) degradation. The central composite design was employed to optimize the operational parameters including irradiation time, pH, photocatalyst mass, and diclofenac concentration, whose optimal values were 213.85 min, 4.31, 0.06 g, and 10.25 mg L−1 for irradiation time, pH, photocatalyst mass, and diclofenac concentration, respectively. Under the optimum conditions, the photocatalytic degradation percentages of diclofenac at desirability function value of 1.0 were found to be 99.56%. The photocatalytic activity of the nanoparticles was also studied under sunlight. Overall, the UV/Vis spectrophotometry and total organic carbon results indicated that the synthesized nanoparticles have an extraordinary photocatalytic activity for the degradation of diclofenac under both purple LED and solar lights. Furthermore, different scavenger agents were investigated.