Graphene-based core/shell hybrid photocatalysts for solar driven degradation of pesticides in water.

Rapid industrialization, urbanization and intensified agricultural activities account for the increased chemical pollution worldwide which poses a major threat to mankind and the environment. Most of the generated chemical pollutants are stable and thus accumulate in the environment, easily transferring from one medium to another, for example, polluted rivers, ground water, soil and food. Current treatment technologies cannot effectively remove these pollutants and the end products of these treatment processes are not eco-friendly. Recent developments have led to oxidative degradation of organic pollutants through catalytic and photocatalytic methods. There have been increased interests to use modified photocatalysts for the complete mineralization of organic pollutants from industrial and agricultural wastes. In this proposed project, attention will focus on degradation of pesticides such as malathion, diazinon, chloropyriphos, ridomil, dacthal, 2,4- dichloro-phenoxy-acetic acid, isoproturon, and commercial formulations like pirimiphos-methyl, methylparathion, phosphamidon, imidaclopride which are commonly used to control pests in South Africa and the Sultanate of Oman. In the proposed project, novel graphene (GR)-based core/shell hybrid photocatalytic materials (TiO2@In2S3/GR; ZnS@In2S3/GR; CdS@TiO2/GR etc.) will be developed and applied for the degradation of these pesticides using solar energy. South Africa and Oman, both with plentiful year-round sunshine offer an ideal environment for solar energy application for environmental remediation. Batch and continuous flow photocatalytic studies will be undertaken to optimize the experimental conditions. The new materials will be characterized by different advanced analytical techniques (FTIR, XRD, UV-Vis, XPS, SEM, TEM). This project will explore the fundamental understanding of the relationship between the structure and the solar-driven catalytic performance of the new material systems.