In-situ Remediation Of Uranium Tailings Contaminated Grounderwater With Natrural Pyrite As PRB Material

Due to the existence of leakage in the groundwater near the tailings pond,based on this situation,this paper carried out the research on the use of natural pyrite as the filling reaction material in PRB for the adsorption of U(?)in water.Through static experiments,the effects of pyrite size,pH,contact time and initial uranium concentration on the effect of U(?)in the adsorbed water were studied to determine the optimal experimental conditions and then,and the adsorption mechanism of pyrite on U(?)were studied in isothermal and kinetics.Through the adsorption column experiment,the adsorption effect of pyrite on U(?)in real environment was simulated under the optimal experimental conditions.Research indicates:(1)The adsorption amount of pyrite to uranium climbed with the increase of initial concentration,but the removal rate decreased.Among them,160-200 mesh pyrite has a better adsorption effect.(2)The experiment was greatly affected by pH,and the adsorption effect was better when the pH was 7-8;and the adsorption equilibriumreached about 12 h during the process of adsorbing uranium from 160-200 mesh pyrite;(3)According to the fitting results of adsorption isotherm model,the adsorption of U(?)by pyrite can be well-fitted with the Langmuir and Freundlich adsorption isotherms,and it is in accordance with the quasi-secondary kinetic model;(4)According to the SEM characterization results,the adsorbed pyrite is smoother than previous state.According to the XRD characterization results,obvious offset peaks appeared before and after adsorption,and uranium oxidation precipitates might be formed.(5)The results of dynamic adsorption column experiments show that the breakthrough point of 160-200 mesh pyrite reached about 28 h,and the adsorption saturation is about 94h;the adsorption rate is about 94.7%,and the permeability is suitable.It can be used for treatment of Uranium groundwater theoretical.