Effects of Hydroxyl and Carboxyl Functional Groups on Calcite Surface Wettability Using Atomic Force Microscopy and Density Functional Theory

Abstract

Surface-active compounds, primarily in asphaltene fractions of crude oil, are responsible for binding the nonpolar oil components to mineral surfaces and, therefore, control wettability changes on reservoir rock/mineral surfaces. Surface wettability changes occur mainly through polar functional groups in these compounds, such as hydroxyl, carboxyl, or carbonyl. By using crude oil with its asphaltene fraction removed, so-called maltenes, we investigate the effect of hydroxyl and carboxyl functional groups on wettability changes of calcite surfaces. Atomic force microscopy (AFM) images show significantly increased adsorption of maltenes on calcite samples treated with two asphaltene surrogates (phenol with a hydroxyl group and benzoic acid with a carboxyl one) than that on water-treated samples. However, the adsorbate patterns are different between those two asphaltene surrogates, suggesting different aggregation mechanisms. In addition, we observed the formation of larger surface-adsorbed droplets on the phenol or benzoic acid-treated calcite samples even for relatively short exposure times (<30 min) to maltenes. Quantum-mechanical calculations show more favorable adsorption for benzoic acid onto the calcite surface both on terraces and step edges. However, when a model oil molecule adsorbs onto those two preadsorbed asphaltene surrogates, nonpolar oil molecules preferentially adsorb onto phenol on terrace sites and benzoic acid on step edges. Overall, benzoic acid changes the calcite surface wettability more significantly than phenol.

Effect of Reservoir Mineralogy on Asphaltene Structure and Remediation Strategy Efficiency

“…This suggests that the asphaltene molecules found in the Arab light, medium, and heavy crude oils do not have carboxylic groups on their structures. This is an important finding because the literature − has primarily linked the changes in reservoir rock wettability to the presence of carboxylic groups on asphaltene structure, which raises the question of how wettability alteration is induced by a sulfur-containing asphaltene molecule. More so, the identification of sulfoxide on the structure of asphaltene samples from Arab light crude oil agrees with the report of Boukir et al who studied only Arab light blend.…”

Complementary Adsorption of Binary Levelers for Highly Uniform Cu Micropillars

“…3-Hydroxy-6-( tert -butyl)pyridine (HBP) and pyridinium tribromide (PTB) were adopted on the basis of their different adsorption behaviors. HBP composed of polar functional groups, such as hydroxyl or carbonyl groups, prevented excessive inhibition of Cu deposition by the weak adsorption on the cathode surface, 18 while another cationic leveler PTB containing positively charged nitrogen 19 promoted strong adsorption on the center area of the cathode, i.e., the electric-field-concentrated region. Therefore, simultaneous use of two levelers enabled a flat surface to be realized on the Cu micropillars, as evidenced by the microscopy results.…”

Virtual Special Issue of ACS Earth and Space Chemistry in Honor of Prof. Michael F. Hochella, Jr.

“…In addition, the three Hochella Symposium organizers were invited by Prof. Joel Blum, Editor-in-Chief of ACS Earth and Space Chemistry , to organize and serve as Guest Editors of a virtual special issue of this journal in honor of Mike Hochella. A total of 20 peer-reviewed manuscripts were accepted for publication in this virtual special issue (), with topics ranging from mineral/water interface chemistry and mineral/organic matter nanoparticles to organic matter/soil chemistry and microbial geochemistry studies. − These papers highlight the importance of nanogeoscience, mineral/aqueous solution interface chemistry, biogeochemistry, and organic matter/soil chemistry in understanding the Earth system.…”