title: Reaction mechanisms for enhancing mineral sequestration of CO2.
abstract: Storage of CO2 through mineral sequestration using olivine has been shown to produce environmentally benign carbonates. However, due to the formation of a rate-limiting reaction product layer, the rate of reaction is insufficient for large-scale applications. We report the results of altering the reactant solution composition and the resultant reaction mechanism to enhance the reaction rate. The products were analyzed for total carbon content with thermal decomposition analysis, product phase compositions with Debye-Scherrer X-ray powder diffraction (XRD), surface morphology with scanning electron microscopy (SEM), and composition with energy dispersive X-ray spectroscopy (EDXS). Carbon analysis showed that an increase in bicarbonate ion activity increased the olivine to carbonate conversion rate. The fastest conversion rate, 63% conversion in one hour, occurred in a solution of 5.5 M KHCO3. Additionally, SEM confirmed that when the bicarbonate ion activity was increased, magnesium carbonate product particles significantly increased in both number density and size and the rate passivating-reaction layer exfoliation was augmented.
authors.affiliation: School of Materials, LeRoy Eyring Center for Solid State Science, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Karalee
authors.initials: K
authors.lastname: Jarvis
authors.forename: R W
authors.initials: RW
authors.lastname: Carpenter
authors.forename: Todd
authors.initials: T
authors.lastname: Windman
authors.forename: Youngchul
authors.initials: Y
authors.lastname: Kim
authors.forename: Ryan
authors.initials: R
authors.lastname: Nunez
authors.forename: Firas
authors.initials: F
authors.lastname: Alawneh
mesh_terms: D001639:Bicarbonates / Q000737:chemistry; D002245:Carbon Dioxide / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry; D012413:Rubidium / Q000737:chemistry; D017693:Sodium Bicarbonate / Q000737:chemistry; D012996:Solutions; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D001639:Bicarbonates; D008903:Minerals; D017680:Potassium Compounds; D012996:Solutions; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; C026329:potassium bicarbonate; D012413:Rubidium