Se(IV)在北山花岗岩上的吸附

Adsorption of Se(IV) onto Beishan Granite

采用批式法研究了粉碎的甘肃北山花岗岩样品(BS03, 600 m)对Se(IV)的吸附作用. 实验结果表明: 在pH 3-7范围内, Se(IV)的吸附分配比(Kd)基本不随pH变化; 当pH > 7时, Se(IV)在北山花岗岩上的Kd随pH的增大而减小. Se(IV)在北山花岗岩上的吸附不随离子强度变化. 北山地下水条件下的Ca2+(4.10×10-3 mo·lL-1)和SO42- (3.17×10-3 mo·lL-1)对Se(IV)的吸附没有影响. 此外, Se(IV)/Eu(III)/北山花岗岩三元吸附体系的实验结果表明, Se(IV) (1.46×10-5 mo·lL-1)和Eu(III) (3.33×10-6 mo·lL-1)在北山花岗岩上的吸附作用相互之间没有表观影响. 通过假定HSeO3-在广义的吸附位点≡SOH上发生了生成≡SHSeO3和≡SSeO3-的两个表面配位反应, 定量解释了Se(IV)的吸附实验结果.

The adsorption of Se（IV） onto crushed Beishan granite （BS03, 600 m） was studied by a batch experimental method. The results showed that the distribution coefficient （Kd） remained almost constant in the pH range of 3-7 and decreased at pH〉7. The adsorption of Se（IV） did not vary with ionic strength. The presence of Ca2. （4.10 ×10^-3 mol· L^-1） and SO4^2- （3.17× 10^-3 mol· L^-1） had no effect on Se（IV） adsorption. Moreover, we found that the adsorption of Se（IV） （1.46× 10^-5 mol· L^-1） and Eu（III） （3.33 × 10-6 mol· L^-1） on Beishan granite had no effect on each other in the ternary adsorption system consisting of Se（IV）/Eu（III）/ granite. The adsorption of Se（IV） onto Beishan granite was quantitatively interpreted by considering the two surface complexation reactions of HseO3 to form -SHSeO3 and =SSeO3- on the =SOH general adsorption sites.