Preparation Of Palygorskite-based Composites And Their Adsorption Properties For Radioactive Iodide

With the increasing demand for energy for economic development,and more importance being attached to national energy structure transformation and energy security strategy,the nuclear power industry of China has entered a stage of rapid development,and the total installed nuclear power capacity is increasing year by year.And the potential risks of radioactive pollution had also gradually aroused people’s concern.Radioactive iodine is one of the inevitable products formed in the reaction of nuclear power operation.Therefore,it is of great significance to study the effective adsorption of radioactive iodine from water.Two different types of palygorskite-based adsorbents were prepared and applied to the chemical and physical adsorption of radioactive iodide respectively.The main contents are as follows:（1）Copper-modified palygorskite（Cu@PAL）was prepared by impregnation-H₂ in situ reduction.And 7.5%Nano copper was firmly loaded in palygorskite（PAL）interlaminar structure by taking advantage of abundant exchangeable cations in structure of palygorskite.Compared with the traditional copper-based adsorbents,the structure of Cu@PAL can effectively delay the oxidation rate of copper.Copper is slowly oxidized by the dissolved oxygen to Cu₂O which can react with I^-.The adsorption capacity of Cu@PAL for I^-can reach 0.914 mmol/g,and the utilization rate of copper is as high as 72%.And the structure can reduce the light visibility of the product after adsorption as well.The desorption rate in deionized water of I^-is only 21.3%,which improves the stability of the product.The composites have reliable adsorption properties in neutral or weak acidic environments with the coexistence of interference ions such as SO₄^2-、NO₃^-or Na⁺.（2）Polymer microspheres（PMs）were prepared by pickling emulsion polymerization with PAL as the matrix,DEAEMA as the monomer,and EGDMA as the cross-linking agent under ultraviolet light,and it was applied to test the adsorption performance of iodide ion.Unlike traditional physical adsorption materials,adsorbption of iodide by this microsphere does not depend on the specific surface area,but rely on the surface protonated amine group.And the adsorption capacity of iodide can be as high as 1.20 mmol/g within only 5 min.PMS still have ultra-high adsorption efficiency of 87.1%after five cycles.Besides,PMs have also excellent adsorption performance to I^-from the river water,groundwater and other environments.