The Preliminary Study On The Fenton Oxidation Technology Of Anion Ion-exchange Resin

In recent years,with the increase of in-service nuclear power units in China,the radioactive waste generated by nuclear power plants will further increase.Radioactive waste ion exchange resin?abbreviation:“ waste resin ”?is a radioactive solid waste generated by nuclear power,usually in the middle or low level of radioactive waste.Radioactive waste resin is the organic waste which has the risk of fire,radiation degradation and radioactive waste leak under storage and disposition conditions.Therefore it is essential that waste resin is effectively disposed with mineralization.Waste resin could be oxidized into small organic molecule,furthermore CO2 and H2 O when disposed by Fenton oxidation technology.The technology has the characteristic that mild reaction condition?100oC or so,atmospheric pressure?,not producing oxynitrides and oxysulfides,little radioactive nuclear elements carried with tail g as and high volume reduction rate.At present,Europe,United States,Japan and Taiwan have developed the equipment of Fenton wet oxidation of waste resin.Domestic research still remains tests in the laboratory stage.The thesis has preliminarily studied wet oxidation technology of anion exchange resin in nuclear level with the support of Department of Radioactive Waste Mangement in China institute for radiation protection,in order to develop the domestic wet oxidation technology applied in waste resin disposition.The main research results are as follows:In the first part,the properties of the nuclear grade IRN78 anion exchange resin were studied.The water content,wet apparent density and wet true density of the anion exchange resin were measured.In the second part,the problem of foam accumulation was studied in the reaction of Fenton wet oxidation of anion resin.The defoam performance of acetic acid,tributyl phosphate,organosilicon deformer A and organosilicon defoamer B were compared.The results showed that organosilicon deformer B was the excellent defoamer of wet oxidation of anion resin.The proper adding method of defoamers was a small amount repeatedly.In the third part,the technological condition of the reaction of Fenton wet oxidation of anion resin was studied.Furthermore the intermediate products appeared in the process of wet oxidation of anion resin were discussed.The effects of pH value,dosage of catalysts and adding rate of hydrogen peroxide on oxydative degradation of anion resin were investigated.The optimized technological parameters were determined.At 95? with initial the value of pH 2,the molar ratio of Fe²⁺/Cu²⁺ catalyst 1:2 and adding rate of hydrogen peroxide1.00mL/min in Fenton wet oxidation reaction,the degradation rate of anion resin reached to 99.7%.The resin degradation rate was improved to more than 99.8% when Co²⁺ instead of 8% Fe²⁺ in Fe²⁺/Cu²⁺ catalyst.Along with degradation process of wet oxidation of anion resin,the intermediate products produced in the reaction were changed.Quaternary ammonium groups off from the skeleton of anion resin and alkyl chain gradually breaked.At the end of the reaction,degradation products were mainly CO2,H2 O and a little amino materials and substituted benzenes.