Th(IV)在高岭土上的吸附行为研究

The sorption behavior of Th( IV) on kaolinite

采用静态批实验的方法,研究了接触时间、pH、离子强度、共存阳离子(Li^+,Na^+,K^+)/阴离子(CO_3^(2-),SO_^(2-)4,PO_4^(3-))、腐殖酸对Th(IV)在高岭土上吸附行为的影响。结果表明,pH和离子强度是影响Th(IV)在高岭土上吸附行为的重要因素,共存阳离子对吸附影响不大,而共存阴离子对吸附有较大的促进/抑制作用。在低pH条件下,HA促进Th(IV)在高岭土的吸附;随着pH升高,HA抑制吸附。表面络合和离子交换是Th(IV)在高岭土上吸附的主要机理。吸附等温线与Langmuir方程可以较好地拟合Th(IV)在高岭土上的吸附等温线。

In this paper,the effect of contact time,pH,ionic strength,coexisting cations( Li+,Na+,K+)/anions( CO2-3 ,SO2-4 ,PO3-4 ) , the humic substances( HA) and initial concentration on the sorption of thorium( Ⅳ) on kaolinite were investigated in batch experi-ments. The results indicated that pH and ionic strength influenced the sorption of Th( Ⅳ) greatly. The co-existing anoions( CO2-3 , SO2-4 ,PO3-4 )had different influences on the sorption of Th(Ⅳ). HA enhanced the sorption at low pH,while decreased the sorption as the increasing pH. The ion exchange and surface complexation are both the dominant mechanisms in the sorption of Th( Ⅳ) on Kao-linite. Langmuir function fitted the experiment well with R2=0. 9939.