Clays and Clay Minerals, Vol. 57, No. 2, 161–167, 2009.
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Authors
Kawano, Motoharu
Hatta, Tamao
Hwang, Jinyeon
Issue Date
2009
Type
Article
Language
Keywords
Periodicals , Geology , Amino Acids , Amorphous Silica , Cationic Species , Dissolution Rate , Rate Enhancement
Alternative Title
Enhancement Of Dissolution Rates Of Amorphous Silica By Interaction With Amino Acids In Solution At Ph 4
Abstract
Amino acids are present in various geochemical environments and they interact with mineral surfaces. To evaluate the effects of amino acids on mineral dissolution at pH conditions less than their isoelectric points (pI), dissolution experiments of X-ray amorphous silica in solutions containing 10.0 mmol/L of various amino acids (cysteine, asparagine, serine, tryptophan, alanine, threonine, histidine, lysine, and arginine) at pH 4 were performed. The results confirmed that basic amino acids (histidine, lysine, and arginine) produce an 8- to 8.5-fold enhancement of the rate of dissolution of amorphous silica compared with an amino acid-free control. Neutral amino acids (cysteine, asparagine, serine, tryptophan, alanine, and threonine) enhanced rates of dissolution by a factor of ~3 to 3.5. The rateenhancement effects of amino acids are controlled by concentrations of the amino acid’s cationic species which interact with the negatively charged >SiO sites at the surface of the amorphous silica.
Description
gsccm57203-kaw.pdf: 229KB
Citation
Clays and Clay Minerals, Vol. 57, No. 2, 161–167, 2009.
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