| As nuclear energy was widely applied, the uranium mining demand has obtained a sustaining development, which lead to a lot of low concentration of uranium containing radioactive wastewater and potentially threats to the ecological environment seriously. However the application of existing uranium adsorption materials has shortages in adsorption capacity, stability, etc. Therefore looking for new adsorption materials of uranium has already be a research hot topic.CS-Bent and OH-Fe-Bent were prepared with Na-bentonite while using chitosan and hydroxyl Fe as intercalated material respectively. The synthesized two composites were applied to adsorb uranium（Ⅵ） from water solution. By changing the p H, initial U（Ⅵ） ions concentration, temperature of environment, and contact time, selected out the best conditions of adsorption. The process of the adsorption were investigated by kinetic and thermodynamic analysis, and the prepared composites were characterized by scanning electron SEM, FTIR, XRD. the main results are as follows :The results indicate that the maximum adsorption of CS-Bent occurs at p H of 6 and the removal rate reaches 97.97% for initial U（Ⅵ） concentration of 10mg﹒L-1 and adsorbent dosage of 1.6g﹒L-1 at 25℃. Meanwhile the adsorption reach equilibrium within 60 min. The adsorption process fits well with the Langmuir isotherm model and pseudo-second-order kinetic model, and the saturated adsorption capacity for U（Ⅵ） irons is 59.52mg﹒g-1. The XRD indicate chitosan has already intercalated bentonite, FTIR and SEM indicate that it has absorb U（Ⅵ） successfully. The used CS-Bent can be desorbed by HCl（the fifth desorption rate is up to 90%）, which indicated CS-Bent can be reusable.The results indicate that the maximum adsorption capacity of OH-Fe-Bent occurs at p H 4 and the removal rate reaches 99.55% for initial U（Ⅵ） concentration of 10mg﹒L-1 and adsorbent dosage of 0.8g﹒L-1 at 15℃. Meanwhile the adsorption reaches equilibrium within 90 min. The adsorption process fit well with the Langmuir isotherm model and pseudo-second-order kinetic mode, and the saturated adsorption capacity for U（Ⅵ） irons is 97.09 mg ﹒ g-1, adsorption mechanism of U（Ⅵ） is a monolayer adsorption. The FTIR and SEM show that the structure of OH-Fe-Bent has no change after absorbing U（Ⅵ） and XRD show that the hydroxyl Fe has already intercalated bentonite. |
