ISBN: 9781243506009

Mineral dissolution is among the most important sets of chemical reactions that occur at and near the Earth's surface. In recent years, efforts to understand mineral dissolution have shif… Mehr…

Mineral dissolution is among the most important sets of chemical reactions that occur at and near the Earth's surface. In recent years, efforts to understand mineral dissolution have shifted to include both macro-scale processes, in which batch reactors are used to determine bulk dissolution rates, and micro-scale processes, in which surface techniques such as Atomic Force Microscopy (AFM) are used to directly observe processes occurring on mineral surfaces during dissolution. Significant Mineral dissolution is among the most important sets of chemical reactions that occur at and near the Earth's surface. In recent years, efforts to understand mineral dissolution have shifted to include both macro-scale processes, in which batch reactors are used to determine bulk dissolution rates, and micro-scale processes, in which surface techniques such as Atomic Force Microscopy (AFM) are used to directly observe processes occurring on mineral surfaces during dissolution. Significant progress that links the physical processes of mineral dissolution to solution chemistry has been achieved through this approach. This study embraces the same strategy and aims at exploring the kinetic and thermodynamic constraints of mineral dissolution reactions and the relations between surface processes and bulk dissolution rates.;An experimental approach through in-situ observations by fluid cell Atomic Force Microscopy (AFM) of the real-time processes was used to investigate crystallographic direction-dependence behaviors of calcite and gypsum during dissolution. AFM observations show simultaneous retreat and advance of the + and - steps on calcite {lcub}101¯4{rcub} cleavage faces, indicating that steps in those two directions may have different solubilities. This result is consistent with the thermodynamic prediction that solubility (Kb) is face dependent as long as energy changes associated with the attachment of individual growth units in symmetrically unrelated directions are different. Furthermore, the measurements of critical step lengths on calcite {lcub}101¯4{rcub} cleavage faces display a clearly defined inverse dependence on saturation state that closely follows the theoretical curve. These findings suggest that the direction-dependence of Kb should be taken into account if the thermodynamic and kinetic properties of monolayer steps are of interest and the size-dependence of Kb should not be ignored when nano- to Books, Science~~General, Thermodynamic-and-kinetic-restraints-on-the-dissolution-of-sparingly-soluble-salt-minerals~~Chunfang-Fan, 999999999, Thermodynamic and kinetic restraints on the dissolution of sparingly soluble salt minerals., Chunfang Fan, 1243506008, BiblioLabsII, , , , , BiblioLabsII<

ISBN: 9781243506009

Mineral dissolution is among the most important sets of chemical reactions that occur at and near the Earth's surface. In recent years, efforts to understand mineral dissolution have shif… Mehr…

Mineral dissolution is among the most important sets of chemical reactions that occur at and near the Earth's surface. In recent years, efforts to understand mineral dissolution have shifted to include both macro-scale processes, in which batch reactors are used to determine bulk dissolution rates, and micro-scale processes, in which surface techniques such as Atomic Force Microscopy (AFM) are used to directly observe processes occurring on mineral surfaces during dissolution. Significant progress that links the physical processes of mineral dissolution to solution chemistry has been achieved through this approach. This study embraces the same strategy and aims at exploring the kinetic and thermodynamic constraints of mineral dissolution reactions and the relations between surface processes and bulk dissolution rates.;An experimental approach through in-situ observations by fluid cell Atomic Force Microscopy (AFM) of the real-time processes was used to investigate crystallographic direction-dependence behaviors of calcite and gypsum during dissolution. AFM observations show simultaneous retreat and advance of the + and - steps on calcite {lcub}101¯4{rcub} cleavage faces, indicating that steps in those two directions may have different solubilities. This result is consistent with the thermodynamic prediction that solubility (Kb) is face dependent as long as energy changes associated with the attachment of individual growth units in symmetrically unrelated directions are different. Furthermore, the measurements of critical step lengths on calcite {lcub}101¯4{rcub} cleavage faces display a clearly defined inverse dependence on saturation state that closely follows the theoretical curve. These findings suggest that the direction-dependence of Kb should be taken into account if the thermodynamic and kinetic properties of monolayer steps are of interest and the size-dependence of Kb should not be ignored when nano- to Books Science~~General Thermodynamic-and-kinetic-restraints-on-the-dissolution-of-sparingly-soluble-salt-minerals~~Chunfang-Fan BiblioLabsII<