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This content will become publicly available on October 26, 2018

Title: Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO 2

Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO 2. With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO 2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO 2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO 2 decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO 2 salting-out effect. Finally, our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.
Authors:
ORCiD logo [1] ; ORCiD logo [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-11633J
Journal ID: ISSN 1520-6106; 658199; TRN: US1703134
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 121; Journal Issue: 51; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1406374