YU Tian1,2, WANG Dan1, DONG Hai-liang1, ZENG Qiang1
1. State Key Laboratory of Biogeology Environmental Geology, China University of Geosciences(Beijing), Beijing 100083, China;
2. School of Water Resources and Environment, China University of Geosciences(Beijing), Beijing 100083, China
Abstract: Clay minerals have ability to adsorb organic matter due to their layered structures and large surface area. However, the role of microbial reduction of structural Fe(III) in clay minerals in organic matter preservation remains unclear. In this study, we studied the effect of microbial iron reduction on the organic matter preservation in an iron-rich clay mineral nontronite. We first intercalated an organic compound (12-Aminolauric acid, ALA) into the interlayer of an iron-rich smectite (nontronite), and then used a sulfate-reducing bacterium Desulfovibrio vulgaris to reduce structural Fe(III) in the ALA-intercalated nontronite (ALA-NAu-2). Our results demonstrated that:1. Desulfovibrio vulgaris was able to reduce structural Fe(III) in NAu-2 and ALA-NAu-2, and AQDS enhanced the reduction rate and the reduction extent. 2. The presence of sulfate increased the reduction rate and extent, suggesting that sulfide produced during sulfate reduction abitically reduced structural Fe(III) in NAu-2 and ALA-NAu-2. 3. The results of X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and total organic carbon (TOC) confirmed that a large amount of ALA was still preserved in the interlayer of nontronite, implying that nontronite has the ability to preserve organic matter.
Keywords: clay mineral bioreduction organic carbon sulfate-reducing bacterium
*Corresponding Author, E-Mail: dongh@cugb.edu.cn
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 33, No.6, 2014, page 790-796
