[Fractionation and relevant influencing factors of rare-earth elements (REEs) in a soil-plant system]

A potted method was carried out in this paper to research fractionation and some influencing factors (including the concentrations of REEs, humic acids and pH of soil) of the REEs (La, Ce, Nd, Sm, Eu, Gd, Tb and Yb) in a soilplant- system. The results showed that the fractionation model of REEs in red soil used in this experiment was similar to the average fractionation model of soil in China. The fractionation model of REEs in wheat root was similar to the model of the soil, but the fractionation model of REEs in wheat tops was not similar to that one. When REEs were added, the fractionation model of REEs in wheat root was changed similarly to that of the soil, but the model of wheat tops was kept constant. The results suggest the adsorbing way of REEs by wheat root and wheat tops were different. Humic acid showed little influence on the fractionation of REEs in wheat. High pH value (pH = 6.7) promoted the adsorption of light REEs by wheat; whereas, low pH value (pH = 4.2) promoted the adsorption of heavy REEs by wheat.