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Sparks, D. L.. 2000. New frontiers in elucidating the kinetics and mechanisms of metal and oxyanion sorption at the soil mineral/water interface. J. Plant Nutri. Soil Sci. 163:563-570.
New frontiers in elucidating the kinetics and mechanisms of metal and oxyanion sorption at the soil mineral/water interface
Donald L. Sparks
Department of Plant and Soil Sciences, University of Delaware. Newark. DE 19716
Key words: metal sorption / oxyanion sorption / XAFS / kinetics /sorption mechanisms
An understanding of the kinetics and mechanisms of metal and oxyanion sorption on soil minerals and soils is fundamental in assessing the speciation, mobility, and bioavailability of metals and oxyanions in natural systems. Traditionally, sorption has been studied using macroscopic equilibrium approaches. It is now well recognized that the kinetics of metal and oxyanion sorption/release must be understood if accurate predictions are to be made about metal/oxyanion fate/mobility and soil remediation. This paper covers aspects of kinetic models and their applicability to heterogeneous systems and the rates and mechanisms of rapid and slow metal and oxyanion sorption reactions. With some metals (e.g. Co, Ni, Zn) residence time affects the rate of metal release while with other metals such as Pb, there is little effect of residence time. To definitively understand the dynamics of sorption mechanisms, one must employ molecular scale approaches. Over the past decade, with the advent of cutting-edge molecular-scale in-situ analytical techniques, significant advances have occurred in determining the speciation and sorption/release mechanisms of metals and oxyanions in the subsurface environment. These frontiers in environmental science have major impacts on: soil remediation strategies, development of predictive models, and contaminant/binavailability assessments. Frontiers in metal sorption at the soil mineral/water interface are highlighted in this review.