Serpentinization and H2 production during an iron-clay interaction experiment at 90C under low CO2 pressure

Interaction of O(-) and H2 at low temperatures.

Reactive collisions between O(-) and H2 have been studied experimentally at temperatures ranging from 10 K to 300 K using a cryogenic radiofrequency 22-pole ion trap. The rate coefficients for associative detachment, leading to H2O + e(-), increase with decreasing temperature and reach a flat maximum of 1.8 × 10(-9) cm(3) s(-1) at temperatures between 20 K and 80 K. There, the overall reaction ...

Redox-driven dissolution of clay minerals by uranium under high pressure CO2 conditions

Growth, CO2 consumption and H2 production of Anabaena variabilis ATCC 29413-U under different irradiances and CO2 concentrations.

AIMS The objective of this study is to develop kinetic models based on batch experiments describing the growth, CO(2) consumption, and H(2) production of Anabaena variabilis ATCC 29413-U(TM) as functions of irradiance and CO(2) concentration. METHODS AND RESULTS A parametric experimental study is performed for irradiances from 1120 to 16100 lux and for initial CO(2) mole fractions from 0.03 t...

H2-rich fluids from serpentinization: geochemical and biotic implications.

Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine w...

The H2/CH4 ratio during serpentinization cannot reliably identify biological signatures

Serpentinization potentially contributes to the origin and evolution of life during early history of the Earth. Serpentinization produces molecular hydrogen (H2) that can be utilized by microorganisms to gain metabolic energy. Methane can be formed through reactions between molecular hydrogen and oxidized carbon (e.g., carbon dioxide) or through biotic processes. A simple criterion, the H2/CH4 ...