Effect of Soil Parameters on the Kinetics of the Displacement of Fe from FeEDDHA Chelates by Cu

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• 作者：Walter D. C. Schenkeveld ; Arjen M. Reichwein ; Erwin J. M. Temminghoff ; Willem H. van Riemsdijk
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：June 28, 2012
• 年：2012
• 卷：116
• 期：25
• 页码：6582-6589
• 全文大小：399K
• 年卷期：v.116,no.25(June 28, 2012)
• ISSN：1520-5215

文摘

In soil application, o,o-FeEDDHA (iron (3+) ethylene diamine-N,N鈥?bis(2-hydroxy phenyl acetic acid) complex) is the active ingredient of FeEDDHA chelate-based Fe fertilizers. The effectiveness of o,o-FeEDDHA is potentially compromised by the displacement of Fe from FeEDDHA by Cu. The actual impact of Cu competition is codetermined by the kinetics of the displacement reaction. In this study, the influence of soil parameters on the displacement kinetics has been examined in goethite suspensions. The displacement reaction predominantly takes place on the reactive surface rather than in solution. The rate at which the o,o-FeEDDHA concentration declined depended on the available reactive surface area, the Cu loading, and the FeEDDHA loading. Soil factors reducing FeEDDHA adsorption (high ionic strength, humic acid adsorption onto the goethite surface, and monovalent instead of divalent cations in the electrolyte) decreased the displacement rate. For meso o,o-FeEDDHA, the displacement rate equation was derived, which is first order in FeEDDHA loading and half order in Cu loading. For soil conditions, the equation can be simplified to an exponential decay function in meso o,o-FeEDDHA solution concentration.