Certain investigations on bare and doped zno nanocrystals for photocatalytic degradation of methylene blue

Abstract

The textile industry is one of the important consumers of variety of dyes along with large number of chemicals for dyeing, printing and finishing processes. The main aim of industrial waste water treatment is to reduce or remove colouring materials and dissolved organic substances to attain environmental demands. Many conventional and non-conventional waste water treatment methods are existing and emerging to remove pollutant materials from waste water but they finally create pollutant in different form. For example, the usage of activated carbon is easy process but it increases the cost in waste disposal. Hence there is an intension to find an alternative cost effective method. The advanced oxidation processes using heterogeneousmsemiconductor photo-catalysis is interesting technique used for dye removal in industrial wastewater. There are various nanostructures semiconductor metal oxides like TiO2, ZnO, WO3 and PbS are used as electron acceptors for eco-friendlyapplications. Among them TiO2 and ZnO are very important, because they have been developed in various nanostructures. They are having ability to produce radicals and decompose most organic pollutants under UV irradiation or sunlight. However, both TiO2 and ZnO are activated only under UV irradiation because of their large band gap, which greatly limits their application in environmental decontamination as solar spectra only contain 5% of UV. newline