Solubility and dissimilatory reduction kinetics of iron(III) oxyhydroxides: A linear free energy relationship
Solubility and dissimilatory reduction kinetics of iron(III) oxyhydroxides: A linear free energy relationship
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DOI：
10.1016/j.gca.2009.06.006
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发表时间：
2009-09-15
影响因子：
5
通讯作者：
Van Cappellen, Philippe
中科院分区：
文献类型：
--
作者：
Bonneville, Steeve;Behrends, Thilo;Van Cappellen, Philippe
由细菌希瓦氏菌腐败的Fe（III）羟基氧化物的还原率作为细菌密度和Fe（III）底物浓度的函数进行测量。结果表明，早期报道的溶度积（*K-so）和主要是不良结晶Fe（III）羟基氧化物的最大细胞特异性还原速率（nu（max））之间的正相关性也适用于不溶性和结晶Fe（III）羟基氧化物。通过透析袋技术在酸性条件（pH 1至2.5）下在25 ℃下测量矿物质溶解度。S.在过量乳酸盐作为电子供体存在下测定腐败菌。在所有情况下，微生物还原率表现出饱和行为相对于Fe（III）羟基氧化物浓度。在双对数尺度上，最大速率nu（最大）和溶解度产品定义了一个单一的线性自由能关系（LFER）的所有Fe（III）羟基氧化物考虑。溶解度比矿物相的比表面积提供了更好的nu（max）预测因子。由铁还原酶和Fe（III）中心之间的电子转移，或由随后的解吸的Fe 2+从氧化铁矿物表面的速率限制，都与观察到的LFER一致。(C)2009爱思唯尔有限公司保留所有权利。
Rates of reduction of Fe(III) oxyhydroxides by the bacterium Shewanella putrefaciens were measured as a function of the bacterial density and the Fe(III) substrate concentration. The results show that an earlier reported positive correlation between the solubility products (*K-so) and the maximum cell-specific reduction rates (nu(max))of predominantly poorly crystalline Fe(III) oxyhydroxides also applies to insoluble and crystalline Fe(III) oxyhydroxides. The mineral solubilities were measured by a dialysis bag technique under acidic conditions (pH 1 up to 2.5) at 25 degrees C. Initial iron reduction rates by S. putrefaciens were determined in the presence of excess lactate as electron donor. In all cases, the microbial reduction rate exhibited saturation behavior with respect to the Fe(III) oxyhydroxide concentration. On a double logarithmic scale, the maximum rates nu(max) and the solubility products defined a single linear free energy relationship (LFER) for all the Fe(III) oxyhydroxides considered. The solubility provided a better predictor of nu(max), than the specific surface area of the mineral phase. A rate limitation by the electron transfer between an iron reductase and a Fe(III) center, or by the subsequent desorption of Fe2+ from the iron oxide mineral surface, are both consistent with the observed LFER. (C) 2009 Elsevier Ltd. All rights reserved.