Review of the mechanisms of ionizing radiation effect on removal of organic, mineral and microbial pollutants from effluent in combination with different chemicals and photocatalysts

Concentration of population and industries in different parts has produced the large volume of wastewater, so that the lack of adequate treatment plants and no attention to proper treatment and pollutants removal techniques has created many environmental problems. The use of ionizing radiation alone to remove pollutants from wastewater needs high absorbed doses and may not be economical on an industrial scale. The application of photocatalytic and chemicals additives to induce oxidizing or reducing species depending on the type of pollutants have suggested for reducing the ionizing radiation dose to remove organic, inorganic and microbial contaminants. There was no study about combination of ionizing radiation with chemicals additives and photocatalysts in Iran, so that the introduction of these technologies and their impact mechanisms is required. According to application of sewage and wastewater mainly in the crops cultivation in Iran and entering of organic and inorganic contaminants to food chain by consumption of these plants, using of modern methods in removing contaminants from wastewater including combination techniques of ionizing radiation and compliance of added effluent with relevant standards is necessary. The present study investigates the mechanisms of integration of ionizing radiation such as gamma and electron beam with photocatalytic and chemicals additives such as methanol, tert-butanol, thiourea, hydrogen peroxide, ozone, pH, various gases, titanium dioxide and etc. to remove of organic, inorganic and biological contaminants and factors affects these mechanisms.