Preprints
https://doi.org/10.5194/bgd-9-557-2012
https://doi.org/10.5194/bgd-9-557-2012

  16 Jan 2012

16 Jan 2012

Review status: this preprint was under review for the journal BG but the revision was not accepted.

Pyrite Oxidation under initially neutral pH conditions and in the presence of Acidithiobacillus ferrooxidans and micromolar hydrogen peroxide

Y. Ma1 and C. Lin2 Y. Ma and C. Lin
  • 1Centre for Ecological and Environmental Technologies, South China Agricultural University, Guangzhou 510642 China
  • 2Australian Centre for Sustainable Catchments, University of Southern Queensland, Toowoomba, QLD 4350 Australia

Abstract. Hydrogen peroxide (H2O2) at a micromolar level played a role in the microbial surface oxidation of pyrite crystals under initially neutral pH. When the mineral-bacteria system was cyclically exposed to 50 μM H2O2, the colonization of \textit{Acidithiobacillus ferrooxidans} onto the mineral surface was markedly enhanced, as compared to the control (no added H2O2). This can be attributed to the effects of H2O2 on increasing the roughness of the mineral surfaces, as well as the acidity and Fe2+ concentration at the mineral-solution interfaces. All of these effects tended to create more favourable nano- to micro-scale environments in the mineral surfaces for the cell adsorption. However, higher H2O2 levels inhibited the attachment of cells onto the mineral surfaces, possibly due to the oxidative stress in the bacteria when they approached the mineral surfaces where high levels of free radicals are present as a result of Fenton-like reactions. The more aggressive nature of H2O2 as an oxidant caused marked surface flaking of the mineral surface. The XPS results suggest that H2O2 accelerated the oxidation of pyrite-S and consequently facilitated the overall corrosion cycle of pyrite surfaces. This was accompanied by pH drop in the solution in contact with the pyrite cubes.

Y. Ma and C. Lin

 
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AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Y. Ma and C. Lin

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