采用批式法研究了粉碎的甘肃北山花岗岩样品(BS03,600m)对Se(IV)的吸附作用.实验结果表明:在pH3—7范围内,Se(IV)的吸附分配比(Kσ)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Ca^2+(4.10×10~mol·L^-1)和SO4^2-(3.17×10^-3mol·L^-1)对Se(IV)的吸附没有影响.此外,Se(IV)/Eu(III)/4k山花岗岩三元吸附体系的实验结果表明,Se(IV)(1.46×10~mol·L^-1)和Eu(III)(3.33×10^-6mol·L^-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.