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  2. Hydrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_cycle

    Because H 2 is the lightest element, atmospheric H 2 can readily be lost to space via Jeans escape, an irreversible process that drives Earth's net mass loss. [7] Photolysis of heavier compounds not prone to escape, such as CH 4 or H 2 O, can also liberate H 2 from the upper atmosphere and contribute to this process.

  3. Hydrogen production - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_production

    High pressure electrolysis is the electrolysis of water by decomposition of water (H 2 O) into oxygen (O 2) and hydrogen gas (H 2) by means of an electric current being passed through the water. The difference with a standard electrolyzer is the compressed hydrogen output around 120–200 bar (1740–2900 psi , 12–20 MPa ). [ 146 ]

  4. Hydrogen purification - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_purification

    Hydrogen can be purified by passing through a membrane composed of palladium and silver. Permeability of the former to hydrogen was discovered back in the 1860s. [2] An alloy with a ca. 3:1 ratio for Pd:Ag is more structural robust than pure Pd, which is the active component that allows the selective diffusion of H 2 through it.

  5. Environmental chemistry - Wikipedia

    en.wikipedia.org/wiki/Environmental_chemistry

    Environmental chemistry is used by the Environment Agency in England, Natural Resources Wales, the United States Environmental Protection Agency, the Association of Public Analysts, and other environmental agencies and research bodies around the world to detect and identify the nature and source of pollutants. These can include:

  6. Hydrogen storage - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_storage

    Hydrogen can be produced using aluminium by reacting it with water. [26] It was previously believed that, to react with water, aluminium must be stripped of its natural oxide layer using caustic substances, alloys, [ 27 ] or mixing with gallium (which produces aluminium nanoparticles that allow 90% of the aluminium to react). [ 28 ]

  7. Natural hydrogen - Wikipedia

    en.wikipedia.org/wiki/Natural_hydrogen

    Modelling suggests that enough natural hydrogen exists to meet humanity's demand for hydrogen for thousands of years, however most of this cannot be extracted economically. [ 5 ] [ 6 ] Natural hydrogen has been identified in many source rocks in areas beyond the sedimentary basins where oil companies typically operate.

  8. Liquid hydrogen - Wikipedia

    en.wikipedia.org/wiki/Liquid_hydrogen

    Liquid hydrogen bubbles forming in two glass flasks at the Bevatron laboratory in 1955 A large hydrogen tank in a vacuum chamber at the Glenn Research Center in Brook Park, Ohio, in 1967 A Linde AG tank for liquid hydrogen at the Museum Autovision in Altlußheim, Germany, in 2008 Two U.S. Department of Transportation placards indicating the presence of hazardous materials, which are used with ...

  9. Ultrapure water - Wikipedia

    en.wikipedia.org/wiki/Ultrapure_water

    Ultrapure water (UPW), high-purity water or highly purified water (HPW) is water that has been purified to uncommonly stringent specifications. Ultrapure water is a term commonly used in manufacturing to emphasize the fact that the water is treated to the highest levels of purity for all contaminant types, including organic and inorganic compounds, dissolved and particulate matter, and ...