Removal of pesticides from water and wastewater by solar-driven photocatalysis

The chemical wastes released by industries and agricultural activities are harmful to the environment, amongst the chemicals included are pesticides, which can cause water pollution. One of the safe and less expensive methods for pesticide removal is the solar-driven photocatalysis, which is the use of sunlight to produce hydroxyl (•OH) radicals by photocatalysis and its application to remove pesticides from water. The application of photocatalytic water purification processes was shown to be effective in degrading and mineralizing the organic compounds by utilizing the solar UV and visible-light spectrum. Photocatalysis reports a step-by-step research methodology in describing the analytical tools to infer the reaction mechanisms, pathway, and kinetics and the application of various techniques for homogeneous and heterogeneous photocatalysis. Different photocatalysts can be used for homogeneous (photo-Fenton and photo-Fenton-like) and heterogeneous (ZnO and TiO2) photocatalytic systems for removal pesticide residues from wastewater. Some of which include the following: TiO2, ZnO, Fe2O3, Bi2O3, WO3, ZnS, CdS, CuS, and C3N4. Evidence from the literature search on photocatalysis showed it has good potential in removing pesticides. However, there is still a need for enlightenment and determine the practical utility of this technique on a commercial scale.