Econ. Environ. Geol. 2009; 42(5): 445-455

Published online October 31, 2009

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

In-situ Precipitation of Arsenic and Copper in Soil by Microbiological Sulfate Reduction

Hae-Young Jang1, Hyo-Taek Chon2* and Jong-Un Lee3

1GS Caltex Corporation, GS Gangnam Tower, Seoul 135-985, Korea
2Department of Energy Resources Engineering, Seoul National University, Seoul 151-744, Korea
3Department of Energy and Resources Engineering, Chonnam National University, Gwangju 500-757, Korea

Correspondence to :

Hyo-Taek Chon

chon@snu.ac.kr

Received: August 25, 2009; Accepted: October 15, 2009

Abstract

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfatereducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox
potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides.
Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

Keywords microbiological sulfate reduction, in-situ precipitation, mine soil, arsenic, copper

Article

Econ. Environ. Geol. 2009; 42(5): 445-455

Published online October 31, 2009

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

In-situ Precipitation of Arsenic and Copper in Soil by Microbiological Sulfate Reduction

Hae-Young Jang1, Hyo-Taek Chon2* and Jong-Un Lee3

1GS Caltex Corporation, GS Gangnam Tower, Seoul 135-985, Korea
2Department of Energy Resources Engineering, Seoul National University, Seoul 151-744, Korea
3Department of Energy and Resources Engineering, Chonnam National University, Gwangju 500-757, Korea

Correspondence to:

Hyo-Taek Chon

chon@snu.ac.kr

Received: August 25, 2009; Accepted: October 15, 2009

Abstract

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfatereducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox
potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides.
Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

Keywords microbiological sulfate reduction, in-situ precipitation, mine soil, arsenic, copper

    KSEEG
    Jun 30, 2024 Vol.57 No.3, pp. 281~352

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