WANG Dan1, DONG Hai-liang1,2
1. Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences(Beijing), Beijing 100083, China;
2. Department of Geology and Environmental Earth Science, Miami University, Ohio 45056, USA
Abstract: In this work, the utilization of organic matters in clay minerals by microorganisms was investigated. Thermophilic bacteria Thermus scotoductus SA-01 and mesophilic bacteria Shewanella putrefaciens CN-32 were selected to reduce structural Fe3+ in the nontronite NAu-2 without other carbon source. The rate and extent of Fe3+ bioreduction were measured by chemical methods. Bioreduced NAu-2 was characterized with X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to investigate mineralogical changes as a result of microbial activity. The amount of total organic carbon released from NAu-2 was determined by an N/C analyzer and the concentrations of different organic compounds released from NAu-2 were measured by high performance liquid chromatography (HPLC). Experimental results demonstrated that: compared with Shewanella putrefaciens CN-32, Thermus scotoductus SA-01 can effectively use organic matter in NAu-2 as the carbon source.We concluded that the reductive dissolution happens when structural Fe3+ in clay minerals is being reduced by microbes. The organic matter associated with nontronite is released into the aqueous solution due to reductive dissolution of nontronite. The organic compounds released from clay minerals are complicated, the rate and the type of organic compound released into solution differ under different temperatures.
Keywords: clay mineral iron reduction organic matter Thermus scotoductus SA-01 Shewanella putrefaciens CN-32
*Corresponding Author, E-Mail: dongh@muohio.edu
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.2, 2015, page 301-309
