Adsorption behaviors of multi-element heavy metal on white pottery clay

Batch experiments are conducted to study the adsorption process on white pottery clay for single (Pb,Cd,Cu), binary (Pb-Cd,Pb-Cu,Cu-Cd) and ternary (Pb-Cd-Cu) solutions. In the single system, the kinetics and isothermal balance adsorption characteristics of different metal ions are analyzed. The results show that each of the adsorption process is fast and can reach balance in three hours. The kinetics adsorptions of Pb, Cu and Cd on white pottery clay are well described by the pseudo-second order model. The Langmuir isotherm models can predict the isothermal adsorption process of three metal ions well on white pottery clay. The order of the maximum adsorption capacity of ions is lead >> copper > cadmium. In the binary system of Pb-Cu and Pb-Cd, Cu can significantly inhibit the adsorption of Pb on white pottery clay, and the adsorption capacity decreases with the increase of the initial concentration of Cu. The effect of Cd is relatively small. For the binary metal solution Cu-Cd , the adsorption of Cd is inhibited when the concentration of Cu is higher than a certain value, and no change occurs over the certain value. In the ternary system, because of the superposition effect of competitive adsorption between ions, three kinds of metal adsorptions decline significantly. The adsorption quantity of Pb decreases with the increase of concentration of Cu and Cd, and the change of Pb concentration has less effect on the adsorption amount of Cu and Cd.