Title: Quartz formation in natural environment with respect to diffusion-reaction of water molecules in nano-scale open spaces
Authors: K. Sato
Addresses: Department of Environmental Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan
Abstract: Steady-state quartz formation in geological environment is an important phenomenon that can address the global environmental issues as diagenetic evolution, biogeochemical cycling, and reservoir formation, but the mechanism is not fully understood. Here, we discuss the steady-state quartz formation on the basis of water migration through nano-scale pores (nanopores) together with the results of x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). XRD and XPS revealed structural evolution toward crystalline quartz with increasing the synthesised time. Water molecules diffuse through 2 Å nanopores in amorphous silica with an activation energy of 2.3 eV. They react with highly reactive nanopore surfaces involving an energy cost of 1.9 eV triggering off the quartz formation. We show experimentally that diffusion and reactions of water molecules in nanopores underlie the formation mechanism of silica quartz.
Keywords: steady-state quartz formation; geological environment; water migration; nanoscale pores; molecule diffusion; molecule reaction; water molecules; nanopores; amorphous silica; silica quartz; diagenetic evolution; biogeochemical cycling; reservoir formation.
International Journal of Environmental Engineering, 2014 Vol.6 No.3, pp.324 - 332
Accepted: 01 Jun 2013
Published online: 30 Aug 2014 *