Hostname: page-component-848d4c4894-x24gv Total loading time: 0 Render date: 2024-05-10T01:24:22.024Z Has data issue: false hasContentIssue false
  • English
  • Français

The kinetics of O2(aq) reduction during oxidative weathering of naturally occurring fracture minerals in groundwater

Published online by Cambridge University Press:  05 July 2018

J. Rivas-Perez ,
E.-L. Tullborg  and
S. A. Banwart
J. Rivas-Perez
Affiliation:
Department of Civil and Environmental Engineering, The University of Bradford, Bradford BD7 2DP, UK
E.-L. Tullborg
Affiliation:
Terralogica AB, Gråbo, Sweden
S. A. Banwart*
Affiliation:
Groundwater Protection and Restoration Group, Department of Civil and Structural Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
*
E-mail: s.a.banwart@sheffield.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

Aqueous chemistry methods assessed the kinetic reactivity and reduction capacity of fracture-filling minerals from a granitic groundwater environment at the Aspo Hard Rock Laboratory, a field station for research and development into the geological disposal of spent nuclear fuel. Naturally occurring fracture filling reacted with oxygenated test solutions of known composition in recirculating batch reactors.

The loss of O2(aq) with time was consistent with second-order reaction kinetics where O2(aq) is consumed through reduction by reaction with structural Fe(II) at the surface of the fracture minerals. Values of the second-order rate constant (k, l mole—1 h—1) varied between experiments within the range 1.7 < log k < 2.9 and values for the total concentration of reducing sites as a measure of the reduction capacity of the mineral (St, mole g—1) varied within the range 8.5 x 10—5 < St < 4.3 x 10—4. Values for the rate constant are somewhat less than those published previously for reaction between O2(aq) and Fe(II) surface complexes; i.e. structural Fe(II) appears to be less reactive than adsorbed Fe(II)(aq) but is significantly more reactive than Fe2+.

Values of the rate constant did not depend on release of network ions from the reacting minerals, and did not vary significantly with pH, mineral mass, specific surface area or mineral Fe(II) content. Oxidative weathering of sulphide minerals does not occur to any measurable extent. When corrected to rock/water ratios for granite aquifers, the rate constants correspond to a half-life for O2(aq) on the order of seconds indicating an essentially instantaneous reaction on repository time scales. Comparison of reducing capacity for the fracture fillings and oxidizing capacity for groundwater saturated with O2(aq) indicates that oxidizing fronts within the geological barrier would travel ~4000 times more slowly than the velocity of groundwater flow.

Keywords

reduction kineticsfracture fillinggroundwater geochemistry.
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 2 , April 2003 , pp. 399 - 414
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Andersson, P., Byegiird, J., Dershowitz, B., Hermanson, D.T., Jeier, P., Tullborg, E.L. and Winberg, A. (2002) A Final Report ofthe TRUE Block Scale. 1. Characterisation and model development, SKB Technical Report TR-02-13. Swedish Nuclear Fuels and Waste Management Company (SKB), Stockholm. ISSN 1404-0344.Google Scholar
Banwart, S.A. (1999) Reduction of iron(III) minerals by natural organic matter in groundwater. Geochimica et Cosmochimica Acta, 63, 2919—2928.CrossRefGoogle Scholar
Banwart, S.A., Gustafsson, E., Laaksoharju, M., Nilsson, A.C., Tullborg, E.L. and Wallin, B. (1994) Large-scale intrusion of shallow water into a vertical fracture zone in crystalline bedrock: Initial hydrochemical perturbation during tunnel construction at the iAsp(D Hard Rock Laboratory, S.E. Sweden. Water Resources Research, 30, 1747—1763.CrossRefGoogle Scholar
Banwart, S.A., Wikberg, P. and Olsson, O. (1997) A testbed for disposal of radioactive waste. Environmental Science and Technology, 31, 510A—514A.Google Scholar
Banwart, S.A., Wikberg, P. and Puigdomenech, I. (1999a) Protecting the redox stability of a deep repository: concepts, results and experience from the Aspo Hard Rock Laboratory. Pp. 85—99 in: Chemical Containment of Wastes in the Geosphere (Metcalfe, R., editor). Special Publication, 157. The Geological Society of London.Google Scholar
Banwart, S.A., Gustafsson, E. and Laaksoharju, M. (1999b)) Hydrological and reactive processes during rapid recharge to fracture zones. The Aspo large scale redox experiment. Applied Geochemistry, 14, 873—892.CrossRefGoogle Scholar
Hering, J. and Stumm, W. (1990) Oxidation and reductive dissolution of minerals. Pp. 427—465 in: Mineral-Water Interface Geochemistry (Hochella, M.F. and White, A.F., editors). Reviews in Mineralogy, 23, Mineralogical Society of America, Washington, D.C.CrossRefGoogle Scholar
Holland, H.D., Lazar, B. and McCaffrey, M. (1986) Evolution of the atmosphere and the oceans. Nature, 320, 27—33.CrossRefGoogle ScholarPubMed
Kornfdlt, K.A., Persson, P.O. and Wikman, H. (1997) Granitoids from the Aspo area, SE Sweden — geological and geochronological data. Geologiska Foreningen i Stockholm Forhadlingar , GFF 114, 459—461Google Scholar
Mazurek, M., Bossart, P. and Eliasson, T. (1997) Classification and Characterisation of Water Conduction Features at Aspo: results of investigations on the outcrop scale. SKB Hard Rock Laboratory International Cooperation Report ICR 97—01. Swedish Nuclear Fuel and Waste Management Company (SKB), Stockholm. ISSN 114—3210.Google Scholar
Miller, W., Alexander, R., McKinley, I. and Smellie, J. (1994) Natural analogue studies in the geological disposal of radioactive wastes. Studies in Environmental Science , 57, Elsevier Publishers, Amsterdam.Google Scholar
Munier, R. (1993) Segmentation, Fragmentation and Jostling of the Baltic Shield with Time. Acta Universitatus Upsaliensis, 37. PhD thesis, University of Uppsala, Sweden.Google Scholar
Puigdomenech, I., Trotignon, L., Kotelnikova, S., Pedersen, K., Griffault, L., Michaud, V., Lartigue, J. -E., Hama, K., Yoshida, H., West, J.M., Bateman, K. , Milodowski, A.E., Banwart, S.A., Rivas Perez, J. and Tullborg, E.-L. (2000) O2 consumption in a granitic environment. Pp. 179—184 in: Scientific Basis for Nuclear Waste Management XXIII (Smith, R.W. and Shoesmith, D.W., editors).Google Scholar
Materials Research Society Symposium Proceedings Vol. 608. Materials Research Society, Warrendale, Pennsylvania, USA.Google Scholar
Puigdomenech, I., Ambrosi, J.P., Eisenhohr, L., Lartigue, J.E., Banwart, S., Bateman, K., Milodowski, A.E., West, J.M., Griffault, L., Gustaffson, E., Hama, K., Yoshida, H., Kotelnikova, S., Pedersen, K., Michaud, V., Trotignon, L., Morosini, M., Rivas-Perez, J. and Tullborg, E.L. (2001) O2 Depletion in Granitic Media. SKB Technical Report TR-01-05. Swedish Nuclear Fuel and Waste Management Company, Stockholm. ISSN 1404-0344.Google Scholar
Schnoor, J.L. (1990) Kinetics of chemical weathering: a comparison of laboratory and field weathering rates. Pp. 475—504 in: Aquatic Chemical Kinetics (Stumm, W., editor). Environmental and Technology Series, Wiley-Interscience, New York.Google Scholar
Stanfors, R., Rhen, I., Tullborg, E.L. and Wikberg, P. (1999) Overview of geological and hydrogeological conditions of the Aspo Hard Rock Laboratory Site. Applied Geochemistry, 14, 819—834.CrossRefGoogle Scholar
Stucki, J.W. and Lear, P.R. (1990) Variable oxidation states of iron in the crystal structure of smectite clay minerals. Pp. 331—358 in: Spectroscopic Characterization of Minerals and their Surfaces (Coyne, L.M., editor). American Chemical Society, Washington, D.C.Google Scholar
Veith, J.A. and Jackson, M.L. (1974) Iron oxidation and reduction effects on structural hydroxyl and layer charge in aqueous suspensions of micaceous vermiculites. Clays and Clay Minerals, 22, 345—353.CrossRefGoogle Scholar
Wehrli, B. (1990) Redox reactions of metal ions at mineral surfaces. Pp. 311—336 in: Aquatic Chemical Kinetics: Reaction Rates of Processes in Natural Waters (Stumm, W., editor). Wiley, New York.Google Scholar
White, A.F. (1990) Heterogeneous electrochemical reactions associated with oxidation of ferrous oxide and silicate surfaces. Pp. 467—509 in: Mineral- Water Interface Geochemistry (Hochella, M.F. and White, A.F., editors). Reviews in Mineralogy, 23, Mineralogical Society of America, Washington, D.C.CrossRefGoogle Scholar
White, A.F. and Yee, A. (1985) Aqueous oxidation- reduction kinetics associated with coupled electron transfer from iron-containing silicates at 25°C. Geochimica et Cosmochimica Acta, 49, 1263—1275.CrossRefGoogle Scholar