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

高氧化态锰铁配合物在海水中的稳定性和反应性的探索研究盐沼沉积物中的黄铁矿氧化和黑海和切萨皮克湾水域中的硫化物氧化可通过厌氧过程发生。这些过程在电子转移步骤是化学的，但可以通过生物过程介导。在溶解铁浓度达到mM水平的盐沼中，由于溶解铁的快速循环，铁（III）有机配合物可以介导黄铁矿氧化。铁循环的主要反应有：(1)有机配体对铁（III）的增溶作用，(2)这些配体将可溶性铁（III）还原为铁（II），可溶性还原硫或黄铁矿，(3)生成的铁（II）被铁（III）矿物氧化（络合成有机螯合物），释放出更多溶解的铁（III），(4)当溶解的硫化物过量时形成硫化铁矿物。只要细菌和/或植物产生有机配体，这种铁的增溶循环就会继续下去。本研究将研究硫化物与可溶性Fe（III）和Mn（III）配合物的反应，并开发一种测定缺氧水中溶解Mn（III）的方法。这些配合物甚至可以作为催化中间体存在于富有机缺氧水中。它们很容易根据化学文献中的方法制备。//

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. //