Novel preparation of zinc oxide based Nanocomposites for the degradation Of organic dyes under sunlight

Abstract

The aim of this research work is to treat textile industry end products (dye wastes) using renewable, cost effective method in an eco-friendly manner. Water available for human use is limited and is often highly polluted which warrants an immediate response to reduce pollution of the aquatic resources. Thousands of scientists continue to focus on this crucial issue and have succeeded in treating polluted waters. Of the several methods used to treat polluted waters, semiconductor based photocatalytic degradation of organic pollutants is an efficient method to treat water in a short time. ZnO and TiO2 are the two main candidates playing a key role in the hotocatalytic degradation of dyes. But bot semiconductors were useful only in the ultraviolet light source as these materials absorb UV light alone and the ecombination rate is very high. These are the major disadvantages of using these materials in the visible light source. When compared with TiO2, ZnO was non-toxic, easy to synthesize and cost of the preparation is very low. Sunlight contains more amount of visible light spectrum (47%) than the UV light. In the first part of the work, we attempted to modify the absorption range and morphology of ZnO nanoparticles (NPs), and increase the photocatalytic efficiency towards anionic and cationic dyes under sunlight irradiation. The prepared ZnO has an absorption peak of 422 nm and all the photoluminescence emissions are in the visible region only. ZnO NPs were found to have chain and plate like morphology. ZnO was in the form of a hexagonal crystal. ZnO NPs completely degraded all the organic dyes in an efficient manner under natural sunlight. newline