Effects of Initial pH and CuS/ZnS Loading in Rhodamine B Photodegradation Under Visible Light Irradiation

Abstract

Copper sulphide doped zinc sulphide (CuS/ZnS) microporous aggregate nanocomposites were synthesised through one-step solid phase thermal decomposition method. This work focused on the effect of initial solution pH and catalyst loading on the degradation of rhodamine B dye using a CuS/ZnS photocatalyst under visible light irradiation. Rhodamine B is a dye widely applied in the textile industry during the colouring process; however, its minute traces in water antagonistically affect the environment and all life forms. The physical and optical properties of the synthesised catalyst were characterised using techniques namely, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET). Optimum rhodamine B dye removal measured 97 % efficiency at 10 gL^-1 loading after 2.5 h and complete mineralisation (100 % efficiency) at a pH of 1 after 4 h under visible irradiation. This study reports a promising CuS/ZnS heterogeneous photocatalyst in rhodamine B removal from wastewater.