Atomic Dislocations and Bond Rupture Govern Dissolution Enhancement under Acoustic Stimulation

Abstract

By focusing the power of sound, acoustic stimulation (i.e., often referred to as sonication) enables numerous "green chemistry" pathways to enhance chemical reaction rates, for instance, of mineral dissolution in aqueous environments. However, a clear understanding of the atomistic mechanism(s) by which acoustic stimulation promotes mineral dissolution remains unclear. Herein, by combining nanoscale observations of dissolving surface topographies using vertical scanning interferometry, quantifications of mineral dissolution rates via analysis of solution compositions using inductively coupled plasma optical emission spectrometry, and classical molecular dynamics simulations, we reveal how acoustic stimulation induces dissolution enhancement. Across a wide range of minerals (Mohs hardness ranging from 3 to 7, surface energy ranging from 0.3 to 7.3 J/m2, and stacking fault energy ranging from 0.8 to 10.0 J/m2), we show that acoustic fields enhance mineral dissolution rates (reactivity) by inducing atomic dislocations and/or atomic bond rupture. The relative contributions of these mechanisms depend on the mineral's underlying mechanical properties. Based on this new understanding, we create a unifying model that comprehensively describes how cavitation and acoustic stimulation processes affect mineral dissolution rates.

Department(s)

Materials Science and Engineering

Comments

National Science Foundation, Grant DMREF-1922167

Keywords and Phrases

Acoustic Stimulation; Activation Energy; Atomic Bond Rupture; Mineral Dissolution; Molecular Dynamics Simulations

International Standard Serial Number (ISSN)

1944-8244; 1944-8252

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 American Chemical Society (ACS), All rights reserved.

Publication Date

09 Dec 2020

PubMed ID

33258375

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