Optimization Of Fenton Reaction Conditions For Treatment Of Radiation Liquid Scintillation Waste Using Response Surface Methodology(RSM)

Fenton reaction is the one of Advanced Oxidation Processes?AOPs?,which utilize ferrous irons(Fe²⁺)as catalysts to induce hydrogen peroxide?H₂O₂?to generate hydroxyl radicals?·OH?.Hydroxyl radicals can oxidize the difficult degradation organics in the wastewater.The organics finally are mineralized as carbon dioxide,water or lower fatty acid with inorganic salts.Therefore,the Fenton reaction can be employed to decompose the organic compound of the radiation liquid scintillation waste.The factors that could influence the Fenton reagent oxidation performance included initial ferrous irons concentration,initial hydrogen peroxide concentrations,initial pH,reaction time and operation temperature.In this study,it was found that all the five factors had effect on the removal of chemical oxygen demand?COD?of liquid scintillation waste sample by single factor experiments and one-way analysis of variance?ANOVA?.From one-way ANOVA,the relatively optimal experiment conditions were gained.However,single factor experiments could not indicate the interaction of between two or more factors.Hence,the response surface methodology?RSM?was employed for further Fenton reagent oxidation performance analysis.The five factors 1/2 fraction central composite design?CCD?with RSM was used for investigation the application of Fenton's reagent in the treatment of liquid scintillation wastes.The regression quadratic model was obtained by experiment data from RSM.According to the results of ANOVA,the p-value of the model was less than 0.0001,which means the predicted model is significant.The coefficient of determination R² was 0.938,the adjust coefficient of determination R²_Adj was 0.880,and the Adeq Precision value was 15.90,which all means the predictability of the model was excellent.The optimal experiment conditions of Fenton reagent in the treatment of liquid scintillation waste were as follow calculated by the regression quadratic model:0.99mmol/L of the initial Fe²⁺concentration,57.5mmol/L of initial H₂O₂ concentration,pH as 2.5,76.6?and 69minutes.In these experiment conditions,the predicted CODCr removal rate was 0.8719,and the actual COD_Cr removal rate of the waste sample was 0.8581.The relative error was 1.58%,which verified the predictability of the numerical model.The results also showed the Fenton reagent had excellent oxidation performance in the treatment of liquid scintillation waste and the response surface methodology was suitable for the design and optimization of the Fenton oxidation processes.