Uranium Removal From Water by Pistia Stratiotes L. and Eichhornia Crassipes

Laboratory hydroponic and static adsorption experiments were conducted on the uranium removal by Pistia stratiotes L. and Eichhornia crassipes from the real uranium mine pit water and the solution which contained different initial uranium concentration. The removal rate of uranium could reach 58% and 48% by 1 g/L of the dried root biomass of Pistia stratiotes L. and Eichhornia crassipes from the real uranium mine pit water (the initial uranium mass concentration was 1.93 mg/L and the initial pH value was 7.83） in 1 h, respectively. After 5 d, the uranium mass concentration could reduce to below 0.3 mg/L. The uranium removal was rapid by the living Pistia stratiotes L. and Eichhornia crassipes which could remove more than 95% of total removal rate taking place in 1 d. Only 10 min was required for the Pistia stratiotes L. which has 400 g fresh weight per individual plant with the initial uranium mass concentration in water of 0.045-4.5 mg/L to reduce to below the standards of the world health organization (30 μg/L). Then 1 d was required for the Eichhornia crassipes which has 400 g fresh weight per individual plant with the initial uranium mass concentration in water of 0.5-4.5 mg/L to reduce to below the national emission standards of China (0.05 mg/L).