文献类型： 外文期刊

作者： Li, Xiaomin ¹ ; Liu, Tongxu ¹ ; Li, Fangbai ¹ ; Zhang, Wei ¹ ; Zhou, Shungui ¹ ; Li, Yongtao ⁵ ;

作者机构： 1.Guangdong Inst Ecoenvironm & Soil Sci, Guangdong Key Lab Agr Environm Pollut Integrated, Guangzhou 510650, Guangdong, Peoples R China

2.Chinese Acad Sci, Inst Water & Soil Conservat, State Key Lab Soil Eros & Dryland Farming Loess P, Yangling 712100, Shanxi, Peoples R China

3.Minist Water Resources, Yangling 712100, Shanxi, Peoples R China

4.S China Agr Univ, Coll Nat Resources & Environm, Guangzhou 510642, Guangdong, Peoples R China

5.S China Agr Univ, Coll Nat Resources & Environm,

关键词： Crystalline degree;Fe(III) availability;Iron oxyhydroxides reduction;Shewanella decolorationis S12;Surface area;Surface properties

期刊名称：JOURNAL OF SOILS AND SEDIMENTS （ 影响因子：3.308； 五年影响因子：3.586 ）

ISSN： 1439-0108

年卷期： 2012 年 12 卷 2 期

页码：

收录情况： SCI

摘要： Dissimilatory iron reduction is an important iron biogeochemical process in subsurface soils. Many researchers have studied the effects of various factors on this process. However, this process in the natural environment is complicated; thus, all the factors should be investigated systematically and simultaneously. The aims of this study were to investigate the effects of Fe(III) availability, surface areas, and crystallinity on Fe(III) reduction in different buffers and to characterize the surface properties of iron minerals. Microbial reductions of four chemically synthesized iron(III) oxyhydroxides [i.e., hydrous ferric oxide (HFO), alpha-FeOOH, gamma-FeOOH, and alpha-Fe2O3] were conducted in batch cultures inoculated with an iron-reducing bacterium, Shewanella decolorationis S12, in Piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES) and Na2HPO4/NaH2PO4 (phosphate buffer solution; PBS) buffers. The hydroxylamine hydrochloride extraction process was employed to determine Fe(III) availability of the oxyhydroxides, and their total surface area was measured using the Brunauer-Emmett-Teller method. Different alpha-Fe2O3 crystalline degrees were prepared by sintering gamma-FeOOH powder from 300A degrees C to 800A degrees C. The surface properties of iron minerals before and after reduction were characterized using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectra. After 35 days of incubation, the order of Fe(III) reduction rates in the PIPES buffer was as follows: HFO > gamma-FeOOH > I +/--FeOOH > I +/--Fe2O3, while that in the PBS buffer was as follows: HFO > I +/--FeOOH > I-3-FeOOH > I +/--Fe2O3. The Michaelis-Menten rate expression was fit to describe the dependence of reduction rates on the available Fe(III). The reduction rates were positively correlated with the surface area but negatively correlated with the crystalline degree. The XRD and FTIR results coupled with the color changes in suspensions showed that in the PIPES buffer, HFO and gamma-FeOOH were reduced to magnetite but no obvious change was found on the surfaces of alpha-FeOOH and alpha-Fe2O3. All iron oxyhydroxides were predominantly reduced to vivianite in the PBS buffer. The present study suggested that S. decolorationis S12 can reduce different structural Fe(III) phases under anaerobic conditions. Iron minerals with higher Fe(III) availability and surface area can result in higher reduction rate, whereas high crystalline degree is not favorable for Fe(III) reduction. Magnetite was the dominant secondary mineral produced from the reduction of HFO and gamma-FeOOH in the PIPES buffer, while that was vivianite upon the bioreduction of all iron oxyhydroxides in the PBS buffer.