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Nachtegaal, M and D.L. Sparks. Nickel sequestration in a mixed kaolinite-humic acid system. SSSA Annual Meeting Abstracts, Nov 5-9, 2000, Minneapolis, MN. p.232.
Understanding nickel speciation in soils is of major importance in predicting the binavailability of nickel. Formation of Ni surface precipitates may play an important role in the immobilization of Ni in non-acidic soils. These precipitates have been shown to form upon contacting Ni with Al bearing clay minerals. Little is known on how organic matter interferes with this sorption process. in real soils, organic matter is an important sink for sorption of Ni, Si and Al. In this paper, the influence of natural humic acids on the formation of surface precipitates in kaolinite suspensions will be presented. In addition, the effects of organic coatings on the stability of sorbed nickel will he discussed. Preliminary results show enhanced Ni sorption in the presence of HA, and an increased stability of sorbed Nickel on coated versus non-coated kaolinite.