Thermodynamic properties and revised Helgeson-Kirkham-Flowers equations of state parameters of the hydrated and dehydrated monomeric silica species at = 0.01-600C, = 1-3000 bars, = 0.35-1.1 g cm, and = 0

Walker, C. S.*; Arthur, R. C.*; Anraku, Sohtaro; Sasamoto, Hiroshi; Mihara, Morihiro

Applied Geochemistry, 175, p.106086_1 - 106086_17, 2024/11

https://doi.org/10.1016/j.apgeochem.2024.106086

The thermodynamic properties and revised Helgeson-Kirkham-Flowers equation of state (r-H-K-F EoS) parameters of the hydrated (Si(OH)(aq), SiO(OH) and SiO(OH)) and fictive dehydrated (SiO(aq), HSiO and SiO) monomeric silicon species are used extensively to describe the pH, composition, temperature, and pressure dependence of formation/breakdown reactions of all silicon-bearing compounds globally. Experimental log10 equilbrium constant, K values describing the formation reactions of the hydrated and dehydrated monomeric silicon species were therefore compiled from the literature, extrapolated to zero ionic strength by specific ion interaction theory as required and used to derive their thermodynamic properties and r-H-K-F EoS parameters. Consideration of all formation reactions in the same study provides a collective, internally consistent update to the thermodynamic properties and r-H-K-F EoS parameters of the monomeric silicon species that can provide a satisfactory match to the experimental log10 K values at = 0.01-600C, = 1-3000 bars, = 0.35-1.1 g cm, and zero ionic strength. These temperature and pressure limits comfortably bracket t=0.01-100C and P =1-270 bars relecant to the geological disposal of radioactive wastes at depths of up to 1 km.

Geochemical studies for geologic disposal of high-level radioactive waste; Research activities in Department of Environmental Safety Research, Japan Atomic Energy Research Institute

; Sato, Tsutomu; Nagano, Tetsushi; Yanase, Nobuyuki; Yamaguchi, Tetsuji; Isobe, Hiroshi; Onuki, Toshihiko; Sekine, Keiichi

JAERI-Review 95-011, 94 Pages, 1995/07

JAERI-Review-95-011.pdf:4.81MB

no abstracts in English

Quantitative performance allocation of multi-barrier system for high-level radioactive waste disposal

; ; ; ; Sakamoto, Yoshiaki; ; ; ; Nagasaki, Shinya*; ; et al.

Nihon Genshiryoku Gakkai-Shi, 37(1), p.59 - 77, 1995/00

https://doi.org/10.3327/jaesj.37.59

no abstracts in English

Chemical behavior of neptunium in groundwater

Nihon Genshiryoku Gakkai-Shi, 32(10), p.970 - 974, 1990/10

https://doi.org/10.3327/jaesj.32.970

no abstracts in English

The Millennium scale monsoon cycles recorded in a sediment core from alpine Tibetan lake

Watanabe, Takahiro; Nara, Fumiko*; Matsunaka, Tetsuya*; Minoura, Koji*; Kakegawa, Takeshi*; Yamasaki, Shinichi*; Tsuchiya, Noriyoshi*; Nakamura, Toshio*; Junbo, W.*; Liping, Z.*

no journal, , 

Understanding of past environmental and geochemical changes is significant issues to estimate global climate variation. Therefore, these changes have been studied by continuous terrestrial sediments. The high-time resolution past environmental changes, especially monsoon fluctuations, have been reported in previous studies using geochemical signatures in stalagmites from Asian caves. However, continuous climate records in Tibetan plateau have not yet been cleared, which a key area to understand mechanism of monsoon fluctuations. In this study, mean grain size and geochemical proxies from lake sediment cores from south Tibetan plateau were used for estimation of past monsoon changes during Holocene. Spectral analysis of the mean grain size in the Tibetan lake indicated 1000-1500 years climate cycles, which might be caused by the changes in solar activities. These monsoon fluctuations based on the mean grain size were also supported by geochemical proxies in this study.

Geochemical-fluid analysis for the natural purification mechanism of arsenic and iron in Ningyo-toge mill tailings pond

Kawasaki, Yohei*; Yagisawa, Makoto*; Granata, G.*; Tokoro, Chiharu*; Ohara, Yoshiyuki

no journal, , 

no abstracts in English