Experimental Correlation Between Interfacial Water Structure and Mineral Reactivity.
We present an experimental demonstration of the effect of solvent structure on the interfacial reactivity of the silica/water interface using in situ vibrational Sum-frequency Generation (vSFG) spectroscopy. The response of the molecular arrangement of the interfacial solvent to the presence of cations is pH dependent with the highest sensitivity at neutral pH, relevant to geochemical and biological environments. The pH-dependent changes in vSFG spectra are in excellent correlation with the enhancement of quartz dissolution in salt water, which was hypothesized by Dove et al. to be due to changes of the interfacial solvent structure at the silica surface. vSFG provides mechanistic insights into silica dissolution and sheds light on the role of ions in altering interfacial solvent ordering, which has implications in fields ranging from protein-water interactions to oil recovery.
†Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.
Shalaka
S
Dewan
‡ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, New Jersey 08801, United States.
Mohsen S
MS
Yeganeh
†Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.
Eric
E
Borguet
salt effect; silica dissolution; silica/water interface; sum-frequency generation