Study On The Preparation And Adsorption Properties Of NaY Zeolite To UO₂²⁺, Sr²⁺ And Cs⁺

With the rapid development of the nuclear industry, emissions of radioactivewasteincreases gradually. A variety of different nuclides contained in radioactive wastewater willcause serious pollution to the surrounding ecology and environment. So disposing ofradioactive waste management and environment work has become one of the main tasks.Wastewater containing uranium mainly comes from the way such as the hydrometallurgyof uranium and nuclear fuel manufacturing production, and the radioisotope waste watercontaining cesium and strontium mainly comes from nuclear fission products. NaY zeoliteand new synthesized inorganic porous materials have been applied in many fieldsincluding catalysis, adsorption, ion-exchange. The raw material of zeolite is abundant,cheap and large adsorption capacity. This paper mainly studied the synthesis,characterization of nanometer NaY zeolite and its adsorption properties to uranium,strontium and cesium. The main findings were as follows:By using fly ash as raw material, nanometer NaY zeolite was synthesized by applyingultrasound-assisted the alkali financial hydrothermal method. The phase and appearacewere characterized through XRD, SEM, TEM and IR. The structure of synthetic zeolitesunder different conditions were compared by XRD and SEM, the results showed that thehighest purity NaY zeolite could be synthesized as following conditions used: NaOHconcentration,2.2M; the synthesis temperature,100℃; the reaction time,12h. It can bedrawn that the grain size distribution of zeolite was more uniform, and the average particlesize was significantly reduced after ultrasound irradiation. On this basis, The UVspectrophotometry and atomic adsorption spectrometry were used to analyze theconcentration of simulate radioactive ions in the wastewater. Synthesized zeolite was usedto adsorb heavy metal ions in radioactive waste water.The adsorption of radioactive waste water using nanometer NaY zeolite was studied.It was shown that the nanometer zeolite could fast adsorpt simulate radioactive ions suchas UO₂²⁺, Sr²⁺, Cs⁺. The adsorption capcity of zeolite to uranium would be21.23mg·g^-1when pH was4, the reaction time was20min and the concentration of uranium solutionwas100mg·L^-1; the adsorption capcity of zeolite to strontium would be98.04mg·g^-1whenpH was7, the reaction time was30min and the concentration of strontium solution was100mg·L^-1; the adsorption capcity of zeolite to cesium would be102.04mg·g^-1when pH was6, the reaction time was30min and the concentration of cesium solution was100mg·L^-1.Adsorption thermodynamics of zeolite to uranium showed that, the adsorbent wassuitable to Langmuir and Freundlich adsorption model, and the adsorption process waspreferential adsorption. The adsorption process of zeolite on uranium was physicaladsorption according to the numerical value of ΔH and ΔG. It could be known from theLangmui radsorption parameters that the adsorption process of zeolite on Sr²⁺wasmultilayer adsorption and preferential adsorption from Freundlich adsorption parameters.The adsorption process of zeolite on Cs⁺was similar to the adsorption process of zeolite onSr²⁺.