钙-铀-碳酸络合物对红土吸附铀性能的影响

摘要

The effect of calcium‐uranyl‐carbonate complex on the adsorption of uranium on red soil was investigated through static adsorption experiment .The results indicate that the increases of pH and concentrations of dissolved carbonate and calcium ion can suppress U(Ⅵ) adsorption on red soil .When pH is 7.0 ,dosage of red soil is 1 g/L and concentrations of calcium ion , dissolved carbonate and uranium are 0.4 mmol/L , 3.8 mmol/L and 50 mg/L respectively , the maximum adsorption capacity is about 4.20 mg/g .The uranium is mainly adsorbed in the forms of UO2 (CO3 )2 -2 ,UO2 (CO3 )4-3 and UO2 CO3(aq) .The c(U‐CO3 )T can be used to predict uranium adsorption capacity of red soil .The c(U‐CO3 )T has a nonlinear relationship with qe ,and the equation is qe =18.2(c(UO2+2 )c(CO2 -3 )(K1 + K2 c(CO2 -3 )+ K3 c2 (CO2 -3 )))0.36 .The research results can provide technical or theoretical references for uranium contaminated red soil remediation .%采用静态实验法研究了钙‐铀‐碳酸络合物对红土吸附铀性能的影响。结果表明：溶液的pH值、总碳酸和钙离子浓度增大会抑制红土对铀的吸附，当pH＝7.0，红土投加量为1 g／L ，钙离子、总碳酸根和初始铀浓度分别为0.4 mmol／L、3.8 mmol／L和50 mg／L时，红土对铀的最大吸附容量约为4.20 mg／g。铀在红土上的吸附形态为 UO2（CO3）2－2、UO2（CO3）4－3和 UO2 CO3（aq）。利用铀‐碳酸络合物总量 c（U‐CO3）T 可预测红土吸附铀的容量 qe ，c（U‐CO3）T 与 qe 呈非线性关系，其方程为 qe ＝18.2（c（UO2＋2）・c（CO2－3）（K1＋ K2 c（CO2－3）＋ K3 c2（CO2－3）））0.36。该研究成果可为铀污染土壤的修复和治理提供技术和理论参考。