MESOGEOCHEMISTRY: GEOCHEMICAL REACTIONS AND MASS TRANSFERS IN A NANO-SCALE PORE SPACE CONFINEMENT

Surface chemistry and ion sorption capability of mesoporous materials are greatly influenced by a nano-scale pore space confinement. As the pore size is reduced to a few nanometers, the separation of surface acidity constants (dpK=pK₂ – pK₁) becomes significantly narrowed, resulting in a high surface charge density on mesopore surfaces. The change in surface acidity constants can significantly affect ion sorption onto nano-scale pore surfaces. Given the fact that nano-scale pores are widely distributed in geologic media and account for over 90% of total mineral surface area, the observed effect of nano-scale pore space confinement has important implications to many fundamental geochemical issues such as the irreversibility of ion sorption/desorption, the bioavailability of subsurface contaminants, the enrichment of trace metals in ore deposits, and the kinetics of mineral dissolution.

Sandia is multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Co., for the United States Department of Energy (US DOE) under Contract DE-AC04-94AL8500.