Study On Green Synthesis And Removal Performance Of Uranium By FeCu/BT

According to the current research status of heavy metal removal methods at home and abroad,the nano-iron material have the advantages of large specific surface area,strong activity,and certain adsorption capacity for the removal of heavy metal ion contaminants.The nano-iron material prepared by the green method is a better choice because of environmental friendliness,low cost,and good removal effect.Bentonite-supported nano-iron-copper bimetal material?FeCu/BT?,a new type of adsorption material which was prepared by reduction of sunflower extract in the experiment.It aims to provide a new way to reduce the oxidation of nano-iron during the preparation process and remove agglomeration in the reaction.Then discuss some parameters of this material in application.Experiment researched how to compound FeCu/BT by a green method.Then studied the removal of uranium from aqueous solutions at different pH,dosage,initial concentration,and ion interference conditions.And analyzed the reaction kinetic model and adsorption isotherm model of the removal of uranium.The morphological and structural characteristics of the materials were analyzed by SEM,EDS,FTIR,XRD,XPS and other methods.And the characterization analysis of the materials after reaction with uranium was used to explore the material adsorption mechanism.The experimental results are as follows:?1?Preparation and characterization of FeCu/BTMix bentonite,0.1mol/L FeSO₄ solution and 0.1mol/L CuSO₄solution at a ratio of 2.24g:200mL:10mL.Then add 200ml sunflower extract with a concentration of 200g/L to prepare FeCu/BT with the best removal effect.The material was mainly composed of micron-level natural bentonite.The nano-iron-copper which particle size was between50-100nm was fixed on the surface in the form of irregular partial spheres.Nano iron-copper bimetal particles were mainly Fe⁰ and Cu⁰inside,and the outer layers were mainly Fe₂O₃,CuO,Fe₃O₄,Cu₂O.The outer layer of the composite material that formed a core-shell like structure was combined with a large number of organic groups?-OH,C-O,C=O,etc.?.?2?Uranium removal effect under various conditionsAt the best condition of pH=7,the dosage is 4g/L,the reaction time is 60min,and the initial uranium concentration is 10mg/L,the uranium removal rate reached 95.5%.The removal rate of uranium by materials had low dependence on pH and temperature.The weak acid radicals had negative effects on the removal reaction.PO₄^3-had the largest negative effect on the reaction.The materials had good oxidation resistance which had good removal performance within 7 days.?3?Kinetic analysis of uranium removal by FeCu/BTThe removal of uranium by the FeCu/BT was well fitted with quasi-second-order kinetic model,and the process was mainly chemical adsorption.At pH=7,the adsorption amount of 4g/L material for 10mg/L uranium is 2.3875mg/g and the adsorption amount for 50mg/L uranium was 11mg/g.The process of removal uranium by the materials was well fitted with Freundlich isothermal adsorption model that was a heterogeneous multi-layer adsorption on the surface and had a variety of adsorption sites.The material was easy to adsorb and has good adsorption performance.?4?Uranium removal mechanismA large amount of uranium is adsorbed on the surface of the FeCu/BT during the reaction and it was also fixed to the mater ial in combination with the organic groups?mainly-OH?attached to the surface of the material.The uranium is adsorbed by iron and copper oxides on the surface and the reduction of uranium by iron mainly occurs inside the material.Cu plays the role of catalysi s,fixation and adsorption.