Adsorption of small organic acids and polyphenols on hematite surfaces: Density Functional Theory + thermodynamics analysis.

Autor: Augustine LJ; University of Iowa, Department of Chemistry, Iowa City, IA 52242, USA. Electronic address: logan-augustine@uiowa.edu., Abbaspour Tamijani A; University of Iowa, Department of Chemistry, Iowa City, IA 52242, USA. Electronic address: ali-abbaspourtamijani@uiowa.edu., Bjorklund JL; University of Iowa, Department of Chemistry, Iowa City, IA 52242, USA. Electronic address: jennifer-bjorklund@uiowa.edu., Al-Abadleh HA; Wilfrid Laurier University, Department of Chemistry and Biochemistry, Waterloo, Ontario N2L 3C5, Canada. Electronic address: halabadleh@wlu.edu., Mason SE; University of Iowa, Department of Chemistry, Iowa City, IA 52242, USA. Electronic address: sara-mason@uiowa.edu.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2022 Mar; Vol. 609, pp. 469-481. Date of Electronic Publication: 2021 Nov 18.
DOI: 10.1016/j.jcis.2021.11.043
Abstrakt: Hypothesis: The interactions of organic molecules with mineral surfaces are influenced by several factors such as adsorbate speciation, surface atomic and electronic structure, and environmental conditions. When coupled with thermodynamic techniques, energetics from atomistic modeling can provide a molecular-level picture of which factors determine reactivity. This is paramount for evaluating the chemical processes which control the fate of these species in the environment.
Experiments: Inner-sphere adsorption of oxalate and pyrocatechol on (001), (110), and (012) α-Fe 2 O 3 surfaces was modeled using Density Functional Theory (DFT). Unique bidentate binding modes were sampled along each facet to study how different adsorbate and surface factors govern site preference. Adsorption energetics were then calculated using a DFT + thermodynamics approach which combines DFT energies with tabulated data and Nernst-based corrective terms to incorporate different experimental parameters.
Findings: Instead of a universal trend, each facet displays a unique factor that dominates site preference based on either strain (001), functional groups (110), or topography (012). Adsorption energies predict favorable inner-sphere adsorption for both molecules but opposite energetic trends with varying pH. Additionally, vibrational analysis was conducted for each system and compared to experimental IR data. The work presented here provides an effective, computational methodology to study numerous adsorption processes occurring at the surface-aqueous interface.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2021 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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