China Nonferrous Metallurgy

Treating low-uranium wastewater directly by natural bentonite has limited removal efficiency. The adsorption capacity will increase significantly after modification, but the current modification technologies are more complicated. In the paper, CTAB/CTS-B adsorption material was successfully prepared with cetyltrimethylammonium bromide and chitosan as modified materials, and characterized by SEM, EDS, XRD, XPS and FTIR. In this work, the adsorption performance and mechanism of CTAB/CTS-B for uranium were mainly studied. The results showed that the maximum removal rate of CTAB/CTS-B for low-concentration uranium-containing wastewater was more than 99% under the conditions of pH 7, dosage 3g/L, adsorption time 2h, rotational speed 180r/min and room temperature. The adsorption process conforms to the pseudo-second-order kinetics and Elovich kinetics equation, and the adsorption behavior is complex with Langmuir equation. Thermodynamic analysis showed that the adsorption enthalpy changed to negative, ΔG⁰ 0, adsorption entropy change ΔG⁰ 0. Analysis of adsorption mechanism showed that ion exchange, electrostatic adsorption, C-C, C-O, amino, hydroxyl and carbonyl played an important role in the adsorption of uranium by CTAB/CTS-B, and the removal of uranium was still good after five cycles, indicating that CTAB/CTS-B has good reusability. CTAB/CTS-B has good adsorption capacity for low-uranium wastewater, and the synthesis technology is relatively simple, which is more suitable for application and promotion.