Competitive adsorption characteristics of Na(I)/Cr(III) and Cu(II)/Cr(III) on GMZ bentonite in their binary solution

The competitive adsorption of Na(I)/Cr(III) and Cr(III)/Cu(II) on GMZ bentonite was studied by batch experiments. The results show that the bentonite has larger total adsorption amount of Cu(II) and Cr(III) in binary ions solution compared to that of single ion solution. Increasing of Na(I) concentration reduces the adsorption capacity of Cr(III) in their binary solution. The phenomenon Cr(III) has a lager adsorption than Cu(II) indicate that the adsorption capacity of Cu(II) is inhibited in their binary solution. The sequence of distribution coefficients (Kd) in the solution as follow: Kd binary (Cr) > Kd single (Cu) > Kd single (Cr) > Kd binary (Cu).