Radiation degradation adsorption treatment of some toxic dyes present in wastewater

The degradation kinetics due to gamma irradiation of aqueous solutions of some organic pollutants (Reactive Yellow Dye, acidic yellow dye and fast yellow dye) were investigated. A combined treatment of gamma irradiation and conventional methods was applied and is much more effective than either alone. Factors affecting the radiolysis of the pollutants such as concentration, irradiation dose, dose rate, and pH of the solutions was studied. Radiochemical degradation yields were calculated to elucidate the mechanism of the degradation process. Also, the feasibility of using granular Activated carbon (GAC), ion exchange resins (Metck I, II, III, IV) for the removal of these pollutants from aqueous solutions were studied. Synergistic treatment of the dye solutions by irradiation methods showed that the saturation of the dye solutions with nitrogen did not enhance the radiation degradation of the dyes, while addition of O2, H2O2 or NaOCI resulted in remarkable enhancement. Adsorption of the dyes onto GAC and some ion-exchangers, showed that GAC has the highest adsorption capacity compared with ion-exchangers. Irradiation followed by adsorption resulted in the removal of these toxic pollutants from wastewater. (author)