title: Kinetic modeling of antimony(V) adsorption-desorption and transport in soils.
abstract: Antimonate [Sb(V)] adsorption-desorption and transport in an acidic red soil (Yingtan) and a calcareous soil (Huanjiang) was investigated using kinetic batch and miscible displacement experiments. Different formulations of a multi-reaction model (MRM) were evaluated for their capabilities of describing the retention and transport mechanisms of Sb(V) in soils. The experimental results showed that adsorption of Sb(V) by two soils was kinetically controlled and largely irreversible. The Sb(V) adsorption capacity and kinetic rate of the acidic red soil was much higher than that of the calcareous soil. The asymmetrical breakthrough curves indicated the strong dominance of non-equilibrium retention of Sb(V). A four step sequential extraction procedure provided evidence that majority of applied Sb(V) was irreversibly retained. A formulation of MRM with two kinetic sorption sites (reversible and irreversible) successfully described Sb(V) adsorption-desorption data. The use of kinetic batch rate coefficients for predictions of breakthrough curves (BTCs) underestimated Sb(V) retention and overestimated its mobility. In an inverse mode with optimized rate coefficients, the MRM formulation was capable of simulating Sb(V) transport in soil columns.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China. Electronic address: hzhang@yic.ac.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Chemical and Environmental Engineering, Qingdao University, Qingdao, Shandong, China.
authors.forename: Lulu
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Zhou
mesh_terms: D000327:Adsorption; D000965:Antimony / Q000032:analysis / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D007700:Kinetics; D008962:Models, Theoretical; D012987:Soil / Q000737:chemistry*
chemical_list: D007477:Ions; D012987:Soil; D000965:Antimony
keywords: Adsorption–desorption; Antimony; Mobility; Soil; Transport