Surface studies of chromate binding to fused quartz/water interfaces

Amanda L. Mifflin, Katie A. Gerth, Brian M. Weiss, Franz M Geiger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

While it is well known that chromium contamination in groundwater represents a considerable threat to the environment, little is known about the heterogeneous processes that govern chromium interaction with solid materials in soil. Using the nonlinear optical laser spectroscopy surface second harmonic generation (SHG), we have studied chromate adsorption and desorption at the fused quartz/liquid water interface in real time, at room temperature and at chromate concentrations between 1 × 10-6 and 2 × 10 -4 M. Adsorbed chromate is spectroscopically identified via a two-photon resonance of one of its ligand-to-metal charge-transfer bands with the fundamental probe light. Adsorption isotherm measurements at 300 K result in a free chromate adsorption energy ΔGads of 38 ± 1 kJ/mol at pH 7. Real-time kinetic measurements of chromate adsorption and desorption show reversible chromate binding to the fused quartz/water interface, consistent with the high mobility of Cr(VI) in soils and the ΔG ads determined from our adsorption isotherm measurements. The pH dependence of chromate binding to the fused quartz/water interface is discussed.

Original languageEnglish (US)
Pages (from-to)6212-6217
Number of pages6
JournalJournal of Physical Chemistry A
Volume107
Issue number32
DOIs
StatePublished - Aug 14 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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