Publication Date

2019

Document Type

Thesis

Committee Members

Steven Higgins, Ph.D. (Advisor); David Dolson, Ph.D. (Committee Member); Ioana Pavel, Ph.D. (Committee Member)

Degree Name

Master of Science (MS)

Abstract

Barite (BaSO4) growth on the (001) surface was studied under solutions of alkali metal chloride salts (LiCl, NaCl, KCl, RbCl and CsCl) as a function of saturation index and ionic strength of the salts at 108 C. When LiCl was used as the background electrolyte, growth hillocks on the barite surface consisted of both [010] steps and <120> steps at ionic strengths of 0.05 and 0.1 M, but [010] steps were not observed at lower ionic strength. In NaCl solutions, hillocks displayed greater prominence of the [010] steps when compared with LiCl. From the saturation state dependent studies, it was found that the kinetic coefficient for step growth increased by 200% when ionic strength increased from 0.01 M LiCl to 0.1 M LiCl. When KCl was used as the background electrolyte, conversion from a surface dominated by <120> steps to a surface consisting primarily of [010] steps was observed, however, a thorough explanation for this phenomenon was hampered by changes in the surface – tip interaction which led to poorly resolved surface features. When RbCl or CsCl was used as the background electrolyte, the growth of hillocks was partially or completely inhibited. The larger cations thus may behave as impurities whose interactions with the kink sites serve to block attachment of barium ions to sulfate-terminated kink sites.

Page Count

55

Department or Program

Department of Chemistry

Year Degree Awarded

2019


Included in

Chemistry Commons

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