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Title: Molecular Dynamics Study of the Bulk and Interface Properties of Frother and Oil with Saltwater and Air

For water treatment purposes, the separation processes involving surfactants and crude oil at seawater-air interfaces are of importance for chemical and energy industries. Little progress has been made in understanding the nanoscale phenomena of surfactants on oily saltwater-air interfaces. This work focuses on using molecular dynamics with a united-atom force field to simulate the interface of linear alkane oil, saltwater, and air with three surfactant frothers: methyl isobutyl carbinol (MIBC), terpineol, and ethyl glycol butyl ether (EGBE). For each frother, although the calculated diffusivities and viscosities are lower than the expected experimental values, our results showed that diffusivity trends between each frother agree with experiments but was not suitable for viscosity. Binary combinations of liquid (frother or saltwater)-air and liquid-liquid interfaces are equilibrated to study the density profiles and interfacial tensions. The calculated surface tensions of the frothers-air interfaces are like that of oil-air, but lower than that of saltwater-air. Only MIBC-air and terpineol-air interfaces agreed with our experimental measurements. For frother-saltwater interfaces, the calculated results showed that terpineol has interfacial tensions higher than those of the MIBC-saltwater. Here, the simulated results indicated that the frother-oil systems underwent mixing such that the density profiles depicted large interfacial thicknesses.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. National Energy Technology Lab. (NETL), Pittsburgh, PA (United States)
  2. National Energy Technology Lab. (NETL), Pittsburgh, PA (United States); AECOM, South Park, PA (United States)
Publication Date:
Report Number(s):
NETL-PUB-20956
Journal ID: ISSN 1520-6106; NETL-PUB-20956; TRN: US1703085
Grant/Contract Number:
E15PG00032
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: 13; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Research Org:
National Energy Technology Laboratory, Pittsburgh, PA, and Morgantown, WV (United States)
Sponsoring Org:
USDOE; National Energy Technology Laboratory (NETL)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1366718