scholarly journals The fate of carbon dioxide in water-rich fluids under extreme conditions

2016 ◽  
Vol 2 (10) ◽  
pp. e1601278 ◽  
Author(s):  
Ding Pan ◽  
Giulia Galli
Keyword(s):  
Carbon Dioxide ◽  
Upper Mantle ◽  
Carbonic Acid ◽  
Global Climate ◽  
Extreme Conditions ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Deep Earth ◽  
Geochemical Models ◽  
Dynamics Simulations

Investigating the fate of dissolved carbon dioxide under extreme conditions is critical to understanding the deep carbon cycle in Earth, a process that ultimately influences global climate change. We used first-principles molecular dynamics simulations to study carbonates and carbon dioxide dissolved in water at pressures (P) and temperatures (T) approximating the conditions of Earth’s upper mantle. Contrary to popular geochemical models assuming that molecular CO2(aq) is the major carbon species present in water under deep Earth conditions, we found that at 11 GPa and 1000 K, carbon exists almost entirely in the forms of solvated carbonate (CO32−) and bicarbonate (HCO3−) ions and that even carbonic acid [H2CO3(aq)] is more abundant than CO2(aq). Furthermore, our simulations revealed that ion pairing between Na+ and CO32−/HCO3− is greatly affected by P-T conditions, decreasing with increasing pressure at 800 to 1000 K. Our results suggest that in Earth’s upper mantle, water-rich geofluids transport a majority of carbon in the form of rapidly interconverting CO32− and HCO3− ions, not solvated CO2(aq) molecules.

scholarly journals The kinetics of the carbon dioxide-carbonic acid reaction

1933 ◽  
Vol 232 (707-720) ◽  
pp. 65-97 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solutions ◽  
Carbonic Acid ◽  
Ionization Constant ◽  
Strong Acid ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Acid Reaction ◽  
Kinetics Of ◽  
H 20

In aqueous solutions of Carbon Dioxide, the concentration of dissolved C02 as such, is, at equilibrium, far greater than the concentration of carbonic acid, [H2C03]. On this account solutions of carbon dioxide are found to be only weakly acidic, although H 2C03 itself, according to THIEL,* and THIEL and STROHECKER and later authors, is a fairly strong acid, with a true first ionization constant of about 2 X 10“4, i.e ., 2 X 10~4 [H2C03] = [H] [HC03]. The “ apparent” first ionization constant of carbonic acid, KCo2> is, however, given by the equation Kcp2 (dissolved [C02] + [H2C03]) = [H] [HODS], and since the dissolved [C02] at equilibrium is found to be of the order of 1000 times greater than the [H2C03], the value of KC02 is correspondingly smaller than 2 X 10~4, and is given as 3 X 10~7. MCBAIN, THIEL ( loc. cit. ) and others have shown that the reversible reaction C02 -f- H 20 0 H 2C03 is a relatively slow one, and hence that the neutralization of dissolved carbon dioxide by alkali differs from the neutralization of other weak acids in not being instantaneous.

Impact of Dursban and Abate on Microbial Numbers and Some Chemical Properties of Standing Ponds

1975 ◽  
Vol 10 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Butcher ◽  
M. Boyer ◽  
CD. Fowle
Keyword(s):  
Carbon Dioxide ◽  
Active Ingredient ◽  
Algal Blooms ◽  
Chemical Properties ◽  
Total Carbon ◽  
Dissolved Carbon ◽  
Photosynthetic Productivity ◽  
Dissolved Carbon Dioxide ◽  
Microbial Numbers

Abstract Eleven small ponds, lined with polyethylene, were used to assess the consequences of applications of *DursbanR at 0.004, 0.030, 0.100 and 1.000 ppm and AbateR at 0.025 and 0.100 ppm active ingredient. The treated ponds showed a more pronounced long-term increase in pH and dissolved oxygen and decreasing total and dissolved carbon dioxide in comparison with untreated ponds. Algal blooms were of longer duration in treated ponds than in controls. Total photosynthetic productivity was higher in treated ponds but bacterial numbers did not change significantly. Photosynthetic productivity was estimated by following the changes in total carbon dioxide.

scholarly journals FORMATION CONDITIONS OF GROUNDWATER OF THE UPPER JURASSIC OF THE CENTRAL REGIONS OF THE ZAURAL MEGAMONOCLYSIS

2021 ◽  
Vol 2 (1) ◽  
pp. 181-190
Author(s):  
Dmitry A. Novikov ◽  
Aleksandr N. Pyrayev ◽  
Fedor F. Dultsev ◽  
Anatoliy V. Chernykh ◽  
Svetlana V. Bakustina ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Isotopic Composition ◽  
Upper Jurassic ◽  
Biogenic Origin ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Oxygen And Hydrogen Isotopes ◽  
Central Regions ◽  
First Results ◽  
Formation Conditions

The article presents the first results of complex isotope-hydrogeochemical studies of reservoir waters of the Upper Jurassic deposits of the central regions of the Zaural megamonoclysis. It was shown that most waters have a narrow distribution of oxygen and hydrogen isotopes (δD from -103.2 to -85.6 ‰ and δO from -15.4 to -12.9 ‰). Some of them have pronounced excursions on the isotopic composition, which indicates a difference in their genesis: from condensate to mixed with ancient infiltrogenic. The isotopic composition of carbon of water-dissolved carbon dioxide (δС from -41.6 to -16.3 ‰) indicates its biogenic origin and the possibility of interstratal flows from overlying horizons.

scholarly journals Carbon dioxide, bicarbonate and carbonate ions in aqueous solutions under deep Earth conditions

2020 ◽  
Vol 22 (19) ◽  
pp. 10717-10725
Author(s):  
Riccardo Dettori ◽  
Davide Donadio
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solutions ◽  
Upper Mantle ◽  
Crust And Upper Mantle ◽  
Effect Of Pressure ◽  
Deep Crust ◽  
Carbonate Ions ◽  
Deep Earth ◽  
Thermodynamic Conditions

We investigate the effect of pressure, temperature and acidity on the composition of water-rich carbon-bearing fluids under thermodynamic conditions that correspond to the Earth's deep crust and upper mantle.

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