{
  "abstract": "The reaction kinetics of reductive pyrite (FeS 2 ) dissolution by H 2 is important to predict the long-term aqueous and gaseous sulfide release in underground hydrogen storage and other engineered subsurface sites. We investigated the rates of pyrite reduction based on sulfide formation as a function of temperature (60-150 • C), H 2 partial pressure (0-150 bar), and pH in situ (~ 4-10) in deoxygenated 0.03 M NaCl solutions. The experiments used natural pyrite powder (ø = 50-100 µm) and were run in hydrothermal batch reactors made of either titanium or Dursan®-coated 316L stainless steel. After experimental durations of ~ 700-900 h, dissolved S -II (aq) concentrations measured by methylene blue spectrophotometry ranged from 10 -5 to 10 -3 M. Long-term pyrite dissolution and concomitant elevated S -II (aq) concentrations were controlled by the formation of secondary pyrrhotite (Fe 1-x S) and magnetite (Fe 3 O 4 ), which prevented the ion activity product of FeS 2 from achieving rapid saturation. Conversely, in the absence of pyrrhotite and magnetite precipitation, the solutions rapidly equilibrated with respect to pyrite, resulting in low S -II (aq) concentrations. Rates of reductive pyrite dissolution were determined at 12 h from total S - II (aq+gas) concentration vs. time data and were found to increase with temperature and H 2 -partial pressure. The rate dependency on pH at 90 • C, 7 bar P H2 was regressed either with an asymmetric 'V'-shaped (two rate-pH domains) or a 'U'-shaped (three rate-pH domains) relation. For this reason, two separate kinetic rate laws were derived, based on the 'U'-regression (E a = 35.2 kJ mol -1 ): r = 10 -5.42 e -35208/RT (P H2 ) 0.37\n\nor the 'V'-regression (E a = 29.4 kJ mol -1 ): r = 10 -5.13 e -29370/RT (a H + ) 0.13 (P H2 ) 0.37\n\nThe performance of both rate laws was validated by reproducing the experimental S -II (aq) concentrations in kinetic models. This comparison determined their applicability to be valid from 60 to 120 • C, 0-150 bar P H2 , and pH ~ 6.7-8.6 ('U' rate law) or pH ~ 4.1-8.6 ('V' rate law). The rate laws are compatible with geochemical reactive transport codes and will enhance the understanding of geochemical fluid-rock-gas interactions in H 2bearing subsurface environments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "name": "Robin Hintzen"
    },
    {
      "name": "Roland Hellmann"
    },
    {
      "name": "Vladimir Roddatis"
    },
    {
      "name": "Julia van Winden"
    },
    {
      "name": "Laurent Truche"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ahk7b6daj1awh.bib",
  "cited_by": 7,
  "doi": "10.1016/j.gca.2025.12.034",
  "fulltext_url": null,
  "id": "ahk7b6daj1awh",
  "issns": [
    "0016-7037",
    "1872-9533"
  ],
  "landing_url": "https://hal.science/hal-05769852v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.chim"
    ],
    [
      "hal",
      "0.sde"
    ],
    [
      "openalex",
      "2305|CO2 Sequestration and Geologic Interactions"
    ]
  ],
  "openalex": "W7116412759",
  "pdf_url": "https://hal.science/hal-05769852/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-29",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/ahk7b6daj1awh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:43Z",
      "native_id": "hal-05769852",
      "source": "hal",
      "url": "https://hal.science/hal-05769852v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "hal:0.chim",
      "subfield": "general"
    },
    {
      "field": "earth",
      "origin": "hal:0.sde",
      "subfield": "environmental-science"
    }
  ],
  "title": "Experimental kinetic rate laws for aqueous pyrite reduction at underground hydrogen storage conditions (60–150 °C, up to 150 bar H2)",
  "title_text": "Experimental kinetic rate laws for aqueous pyrite reduction at underground hydrogen storage conditions (60–150 °C, up to 150 bar H2)",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:43Z",
  "url": "https://research.draconitic.com/paper/ahk7b6daj1awh",
  "venue": "Geochimica et Cosmochimica Acta",
  "versions": []
}