SGER: Exploratory Research on the Stability and Reactivity of Higher Oxidation State Mn and Fe Complexes in Seawater

海水中高氧化态锰铁络合物的稳定性和反应活性的探讨盐沼沉积物中的黄铁矿氧化和黑海和切萨皮克湾水域的硫化物氧化可通过厌氧过程进行。这些过程在电子转移步骤是化学的，但可以通过生物过程进行调节。在溶解铁浓度达到毫米级的盐沼中，由于溶解铁的快速循环，铁(III)有机络合物可以促进黄铁矿的氧化。铁循环的主要反应是(1)有机配体对Fe(III)的增溶，(2)这些配体将可溶的Fe(III)还原为Fe(II)，可溶的还原硫或黄铁矿，(3)生成的Fe(II)(与有机络合物络合)被Fe(III)矿物氧化，释放出更多的溶解的Fe(III)，(4)溶解硫化物过多时形成铁硫化物矿物。只要细菌和/或植物产生有机配体，铁的溶解循环就会继续下去。研究了硫化物与可溶性Fe(III)、Mn(III)络合物的反应，建立了测定缺氧水中溶解性Mn(III)的方法。这些络合物甚至应该以催化中间体的形式存在于富含有机的缺氧水中。根据化学文献中的方法，它们很容易制备。//

Exploratory Research On The Stability And Reactivity Of Higher Oxidation State Mn and Fe Complexes In Seawater Pyrite oxidation in salt marsh sediments and sulfide oxidation in the waters of the Black Sea and the Chesapeake Bay can occur by anaerobic processes. These processes are chemical at the electron transfer step, but can be mediated by biological processes. In salt marshes where dissolved Fe concentrations reach mM levels, pyrite oxidation can be mediated by Fe (III) organic complexes because of the rapid cycling of dissolved Fe. The main reactions of the iron cycle are (1) solubilization of Fe(III) by organic ligands, (2) reduction of soluble Fe(III) to Fe(II) by these ligands, soluble reduced sulfur or pyrite, (3) the oxidation of the resulting Fe(II) (complexed to organic chelates) by Fe(III) minerals releasing more dissolved Fe(III), and (4) the formation of iron sulfide minerals when dissolved sulfide is in excess. This cycle of iron solubilization will continue as long as bacteria and/or plants produce organic ligands. This study will investigate the reaction of sulfide with soluble Fe(III) and Mn(III) complexes and develop a method for the determination of dissolved Mn(III) in anoxic waters. These complexes should exist even as catalytic intermediates in organic rich anoxic waters. They are easily prepared based on methods in the chemical literature. //