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Chemisorption And Precipitation Reactions
Citation:
FORD, R. G. Chemisorption And Precipitation Reactions. Chapter 17, P.M. Huang, Y. Li, and M.E. Sumner (ed.), Handbook of Soil Sciences: Properties and Processes, Second Edition. CRC Press - Taylor & Francis Group, LLC, Boca Raton, FL, Part II :17-1 - 17-21, (2011).
Impact/Purpose:
To provide a synopsis of the current phenomenological understanding of governing reaction processes based on observations of solid-phase partitioning reactions in controlled monomineralic systems and the chemical speciation of ions partitioned to solid surfaces in soil systems.
Description:
The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suite of chemical bonding reactions between solutes in solution and chemical moieties at the surface of existing soil solids, whereas precipitation reactions conventionally involve chemical bonding between solutes in solution to form a new solid phase. The purpose of this chapter is to provide a synopsis of the current phenomenological understanding of governing reaction processes based on observations of solid-phase partitioning reactions in controlled monomineralic systems and the chemical speciation of ions partitioned to solid surfaces in soil systems. Conceptual distinctions between surface complexation, coprecipitation, and precipitation reactions with reference to published observations for experimental and field systems are discussed. The role of abiotic and biotic processes is also discussed in the context of element fluxes that impact the partitioning process. Finally, observations of solid-phase partitioning for a selection of cationic and anionic species in soils are summarized to illustrate the complexity of these reaction processes in soil systems.