Sorption isotherms and kinetics of Sb(V) on several Chinese soils with different physicochemical properties

Abstract

Sorption of antimony on soils is the primary factor that influences its immobilization and migration in the environment. In the present study, the sorption of Sb(V) onto seven Chinese soils with different physicochemical properties was investigated for exploring the relationship between the sorption capacity of Sb(V) and the physicochemical properties of the soils. Sorption isotherms and kinetics experiments were performed to ascertain the sorption capacity and the kinetic rate, respectively. The relationship between the sorption capacity of Sb(V) and the physicochemical properties of the soils was analyzed by multiple linear regressions. The results showed that the sorption isotherms fitted with both the Langmuir and Freundlich equations very well (R 2 = 0.936–0.997), and the sorption kinetic of Sb(V) onto the seven Chinese soils followed a pseudo-second-order reaction. The maximum sorption capacity of Sb(V) on the soils ranged from 134 to 1,333 mg kg−1. Nearly 94 % of the variability in maximum sorption of Sb(V) modeled by Freundlich equation could be described by FeDCB (dithionite–citrate–bicarbonicum extractable), and nearly 98 % of the variability could be described by FeDCB and AlDCB. Multiple linear regressions can be successfully applied to analyzing the relationship between sorption capacity and soil properties. FeDCB and AlDCB played important roles in Sb(V) sorption onto soils. It would be useful to understand the environmental behaviors of Sb and for the implementation of risk assessment management and remediation strategies of Sb.