Monosilicate adsorption by ferrihydrite and goethite at pH 3-6

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The constant capacitance model and the Elovich equation were combined in the following mathematical expression enabling calculation of the amount of silicic acid adsorbed by iron oxides as a function of the Si concentration, pH, soil:solution ratio, and reaction time: [GRAPHICS] K(a1) is the protolytic surface constant and K(Si) is the stability constant for the Fe oxide-silicate surface complex; -logK(a1) = 6.40-0.54(8-pH) and logK(Si) = 3.85 for ferrihydrite and goethite. Good agreement was found between calculated Si adsorption and the amount actually found to be adsorbed by synthetic ferrihydrite and goethite at different pH (3-6), Si concentration (1-600 muM), solid:solution ratio (1:300, 1:1200) and reaction time (1-480h).
Original languageEnglish
JournalSoil Science
Issue number1
Pages (from-to)40-46
Number of pages7
Publication statusPublished - 1994

ID: 8028989