China Nonferrous Metallurgy

Bentonite is oftern used for adsorption and solidification of radionuclide uranium, but the silica structure of natural bentonite has a strong hydrophilicity, leading to a poor adsorption effect on pollutants. In this paper, DTAB organic modified bentonite was prepared by co-precipitation method with DTAB as a modifier and bentonite as raw material.And the effects of pH value,dosage of modified bentonite, temperature,adsorption time and initial concentration of U(VI) solution on the adsorption of U(VI) contained in wastewater by DTAB organic modified bentonite were investigated. It is concluded that the adsorption effect of modified bentonite is greatly improved with a wider pore and spacing as well as a large number of hydrophobic functional groups. The experimental results show that the best adsorption effect is achieved at pH 40, the modified bentonite dosage of 01g (2g/L), the temperature of 33315K, the initial concentration of U(VI)-containing wastewateras 10mg/L and the adsorption time of 240min, and the U(VI) removal rate could reach 9957% under such condition. The kinetics-equation fitting shows that the adsorption model of the material is in accordance with the quasi-secondary kinetic model, indicating that the adsorption is dominated by chemisorption. The isothermal adsorption model fitting shows that the adsorption model is more consistent with the Langmuir isothermal adsorption model, and the fitted maximum adsorption amount is 3445mg/g.