Application of Advanced Oxidation Processes (AOP) such as sono, photo and sonophoto catalysis in the purification of polluted water under ambient conditions involve the formation and participation of Reactive Oxygen Species (ROS) like ·OH, HO2·, O2(-), H2O2 etc. Among these, H2O2 is the most stable and is also a precursor for the reactive free radicals. Current investigations on the ZnO mediated sono, photo and sonophoto catalytic degradation of phenol pollutant in water reveal that H2O2 formed in situ cannot be quantitatively correlated with the degradation of the pollutant. The concentration of H2O2 formed does not increase corresponding to phenol degradation and reaches a plateau or varies in a wave-like fashion (oscillation) with well defined crests and troughs, indicating concurrent formation and decomposition. The concentration at which decomposition overtakes formation or formation overtakes decomposition is sensitive to the reaction conditions. Direct photolysis of H2O2 in the absence of catalyst or the presence of pre-equilibrated (with the adsorption of H2O2) catalyst in the absence of light does not lead to the oscillation. The phenomenon is more pronounced in sonocatalysis, the intensity of oscillation being in the order sonocatalysis>photocatalysis⩾sonophotocatalysis while the degradation of phenol follows the order sonophotocatalysis>photocatalysis>sonocatalysis>sonolysis>photolysis. In the case of sonocatalysis, the oscillation continues for some more time after discontinuing the US irradiation indicating that the reactive free radicals as well as the trapped electrons and holes which interact with H2O2 have longer life time (memory effect).

Contamination of water by chemical and bacterial pollutants as well as ‘white pollution’ caused by carelessly discarded waste plastics are major environmental problems. In the current study, the possibility of using semiconductor photocatalysis for the removal of last traces of organic water pollutants of different types is investigated. Semiconductors ZnO and TiO

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The significant studies of the texture by human hands of polyethylene carry bags [different types that are used for the experimentation are yellow paper plastic (polyethylene) bag sheet, pure transparent polythene carry bag sheet, yellow polythene carry bag sheet, and a piece of a hard plastic coffee cup] with and without incubation inside the crown of the soil part has been compared. The comparisons were tabulated with a conclusion that trivial fraction levels of degradation of polyethylene carry covers. The results are represented in a series so as to which variety resolve degrade greater (++++) percentage or lesser (+) percentage levels with an index parameter of 'texture' of feeling smooth or rough.