Green synthesis of Cadmium Sulphide nanoparticles for the photodegradation of Malachite green dye, Sulfisoxazole and removal of bacteria

Abstract

The development in nanoscience has led to cleaner and safer semiconductor materials that can be used for degrading toxic and resistant pollutants in water. Ecological and environmentally friendliness’s are added features that the semiconductor photocatalyst should possess and these are incorporated via green synthetic approaches. Hence, in this study, Sutherlandia frutescence (S. frutescens), leaf extract was used during the synthesis of Cadmium Sulphide (CdS) nanostructures, as a reducing and stabilising agent. Their morphological analysis revealed the presence of spherical particles. Structural analysis by XRD confirmed the presence of hexagonal S. frutescens CdS nanostructures. Furthermore, through FTIR, the deposition of the phytochemicals on the S. frutescens CdS was confirmed. The S. frutescens CdS nanostructures exhibited a bandgap of 3.55 eV. Thus, they were further investigated for their degradation of Malachite Green dye and Sulfisoxazole (SIZ) under UV light irradiation. Approximately, 91% photocatalytic efficiency was achieved for MG (dye:10 mg/L, catalyst: 50 mg, pH: 2) and the materials could be recycled up to 3 times without using stability. The photogenerated electrons were the major contributors to the photodegradation. The pharmaceutical pollutant, sulfisoxazole, had a 68% degradation after 120 min. In addition, the antibacterial activity of the S. frutescens CdS gave excellent removal against all the bacterial strains for both the model and real water pollutants. This study has shown that various pollutants can be degraded (MG and SIZ) and removed (bacteria) using the S. frutescens CdS.