Chemical affinity and pH effects on chlorite dissolution kinetics under geological CO₂ sequestration related conditions

Journal Article · Wed Jan 14 00:00:00 EST 2015 · Chemical Geology

DOI:https://doi.org/10.1016/j.chemgeo.2015.01.001· OSTI ID:1210470

Zhang, Shuo ^[1]; Yang, Li ^[2]; DePaolo, Donald J. ^[1]; Steefel, Carl I. ^[2]

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1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

The kinetic dissolution of Flagstaff Hill chlorite (CCa-2 from Clay Minerals Society), (Mg_4.55Al_1.23Fe_0.12)(Al_1.04Si_2.96)O₁₀(OH)₈, was investigated using a well-mixed flow-through reactor at 100 °C, pH values ranging from 3.0 to 7.5, and variable saturation states. The objective was to measure the dependence of chlorite dissolution rate on pH as well as on degree of undersaturation under conditions applicable to geologic carbon storage. A batch experiment was conducted to determine the equilibrium constant of the dissolution reaction at 100 °C for the chlorite mineral phase used in this study. A series of experiments was run at varying CO₂ partial pressures (0–60 bars) and different flow rates (0.01–0.25 ml/min). Here, we use our experimental results in conjunction with previously published data to separate the effects of pH and solution saturation state. At constant pH, the chlorite dissolution rate decreases slowly as a function of the Gibbs free energy of reaction (ΔG_r), which is a quantitative measure of the degree of undersaturation.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Nanoscale Control of Geologic CO2 (NCGC)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02–05CH11231; AC02-CH11231
• OSTI ID: 1210470
• Alternate ID(s): OSTI ID: 1246656
• Journal Information: Chemical Geology, Vol. 396, Issue C; Related Information: NCGC partners with Lawrence Berkeley National Laboratory (lead); University of California, Davis; Lawrence Livermore National Laboratory; Massachusetts Institute of Technology; Ohio State University; Oak Ridge National Laboratory; Washington University, St. Louis; ISSN 0009-2541
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
58 GEOSCIENCES
bio-inspired
mechanical behavior
carbon sequestration
chlorite dissolution kinetics
chemical affinity effects
CO2 sequestration