title: Self-Generated Electrokinetic Fluid Flows during Pseudomorphic Mineral Replacement Reactions.
abstract: Pseudomorphic mineral replacement reactions involve one mineral phase replacing another, while preserving the original mineral's size and texture. Macroscopically, these transformations are driven by system-wide equilibration through dissolution and precipitation reactions. It is unclear, however, how replacement occurs on the molecular scale and what role dissolved ion transport plays. Here, we develop a new quantitative framework to explain the pseudomorphic replacement of KBr crystal in a saturated KCl solution through a combination of microscopic, spectroscopic, and modeling techniques. Our observations reveal that pseudomorphic mineral replacement (pMRR) is transport-controlled for this system and that convective fluid flows, caused by diffusioosmosis, play a key role in the ion transport process across the reaction-induced pores in the product phase. Our findings have important implications for understanding mineral transformations in natural environments and suggest that replacement could be exploited in commercial and laboratory applications.
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Kar
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: McEldrew
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Stout
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Mays
authors.affiliation: Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Aditya
authors.initials: A
authors.lastname: Khair
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Darrell
authors.initials: D
authors.lastname: Velegol
authors.affiliation: Department of Civil & Environmental Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gorski