Phosphate imposed limitations on biological reduction and alteration of ferrihydrite
Phosphate imposed limitations on biological reduction and alteration of ferrihydrite
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DOI：
10.1021/es060695p
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发表时间：
2007-01-01
影响因子：
11.4
通讯作者：
Fendorf, Scott
中科院分区：
文献类型：
--
作者：
Borch, Thomas;Masue, Yoko;Fendorf, Scott
生物地球化学转化（包括溶解）的铁（氢）氧化物产生的异化还原有显着的影响的命运和运输的营养物质和污染物在地下环境。尽管原始（未反应）矿物具有反应性，但天然环境中的铁（氢）氧化物可能具有不同的反应性，部分原因是表面组成的变化。因此，在这里，我们探讨了表面改性引起的磷酸盐吸附对水合铁矿还原希瓦氏菌腐败在静态和平流条件下的影响。磷酸盐引起的表面反应性的改变的程度，降低Fe（III）还原几乎线性增加P表面覆盖度，和铁的生物矿化的途径。磁铁矿是最明显的矿化产物，而少量的蓝铁矿和绿色锈状相形成于具有高含水浓度的磷酸盐、亚铁和碳酸氢盐的系统中。针铁矿和纤铁矿，在低亚铁浓度的特征生物矿化产物，在吸附的磷酸盐的存在下被抑制。因此，铁（氢）氧化物的反应性与表面组成的变化，如那些在这里指出的磷酸盐的偏差，需要考虑在自然环境中。
Biogeochemical transformation (inclusive of dissolution) of iron (hydr)oxides resulting from dissimilatory reduction has a pronounced impact on the fate and transport of nutrients and contaminants in subsurface environments. Despite the reactivity noted for pristine (unreacted) minerals, iron (hydr)oxides within native environments will likely have a different reactivity owing in part to changes in surface composition. Accordingly, here we explore the impact of surface modifications induced by phosphate adsorption on ferrihydrite reduction by Shewanella putrefaciens under static and advective flow conditions. Alterations in surface reactivity induced by phosphate changes the extent, decreasing Fe(III) reduction nearly linearly with increasing P surface coverage, and pathway of iron biomineralization. Magnetite is the most appreciable mineralization product while minor amounts of vivianite and green rust-like phases are formed in systems having high aqueous concentrations of phosphate, ferrous iron, and bicarbonate. Goethite and lepidocrocite, characteristic biomineralization products at low ferrous-iron concentrations, are inhibited in the presence of adsorbed phosphate. Thus, deviations in iron (hydr)oxide reactivity with changes in surface composition, such as those noted here for phosphate, need to be considered within natural environments.