Calcium-Aluminum bimetallic compound enhanced bentonite for uranium removal from water

[Results] The results indicate that the equilibrium adsorption capacity of uranium is approximately 74.82 mg∙g-1 at a pH of 4.0 and a temperature of 25°C. The adsorption capacity of CA-BTN for uranium increases with the initial pH value, initial U(VI) concentration, and temperature, while still maintaining good uranium removal performance even in the presence of interfering ions. Under the conditions of an initial uranium concentration of 10.00 mg/L, a pH of 4.0, and a temperature of 25°C, the uranium removal rate exceeds 98%.

The adsorption behavior is a spontaneous monolayer chemisorption process, which can be described by the pseudo-second-order kinetics model and Langmuir fitting. Hydrophilicity measurements indicate that CA-BTN exhibits excellent hydrophilicity. XRD and SEM-EDS results reveal the crystalline structure and micro-morphology of bentonite and calcium-aluminum bimetallic compounds present in CA-BTN.

The results from XPS and FTIR tests indicate that CA-BTN removes uranium through a coordination mechanism without undergoing redox reactions. [Conclusions] This study provides technical and theoretical references for the synthesis of bentonite-based adsorbent materials and their application in the removal of uranium from radioactive wastewater.