Microbially Accelerated Carbonate Mineral Precipitation as a Strategy for in Situ Carbon Sequestration and Rehabilitation of Asbestos Mine Sites

详细信息    查看全文

• 作者：Jenine McCutcheon ; Siobhan A. Wilson ; Gordon Southam
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：February 2, 2016
• 年：2016
• 卷：50
• 期：3
• 页码：1419-1427
• 全文大小：697K
• ISSN：1520-5851

文摘

A microbially accelerated process for the precipitation of carbonate minerals was implemented in a sample of serpentinite mine tailings collected from the abandoned Woodsreef Asbestos Mine in New South Wales, Australia as a strategy to sequester atmospheric CO₂ while also stabilizing the tailings. Tailings were leached using sulfuric acid in reaction columns and subsequently inoculated with an alkalinity-generating cyanobacteria-dominated microbial consortium that was enriched from pit waters at the Woodsreef Mine. Leaching conditions that dissolved 14% of the magnesium from the serpentinite tailings while maintaining circumneutral pH (1800 ppm, pH 6.3) were employed in the experiment. The mineralogy, water chemistry, and microbial colonization of the columns were characterized following the experiment. Micro-X-ray diffraction was used to identify carbonate precipitates as dypingite [Mg₅(CO₃)₄(OH)₂·5H₂O] and hydromagnesite [Mg₅(CO₃)₄(OH)₂·4H₂O] with minor nesquehonite (MgCO₃·3H₂O). Scanning electron microscopy revealed that carbonate mineral precipitates form directly on the filamentous cyanobacteria. These findings demonstrate the ability of these organisms to generate localized supersaturating microenvironments of high concentrations of adsorbed magnesium and photosynthetically generated carbonate ions while also acting as nucleation sites for carbonate precipitation. This study is the first step toward implementing in situ carbon sequestration in serpentinite mine tailings via microbial carbonate precipitation reactions.