Metal Sulfur Complexes in Marine Waters

在缺氧和硫化环境中，微量金属的浓度受金属硫化物相的沉淀以及金属被硫化物和其他硫化物络合的控制。各种具有环境意义的金属与硫化物、硫代硫酸盐和多硫化物的稳定常数将被测定。常数将通过伏安法利用硫种和/或金属的峰来获得。这项研究还需要滴定酸和碱的配合物，以确定附着在硫类上的质子数。这项工作将建立在对海水的初步研究的基础上，该研究表明，铁（II）和硫化物形成两种配合物，即Fe(SH)+ (log B=5.5)和Fe2(SH)3+ (log B= 11.1)。这些常数比用线性自由能关系计算的常数高几个数量级。事实上，Fe2(SH)3+不能通过这种方法或任何使用硫化物作为滴定剂的实验方法来预测。因此，铁（II）在缺氧界面和硫化物环境中的溶解度可以比以前的估计提高。

9314349 LUTHER The concentration of trace metals in anoxic and sulfidic environments is controlled by the precipitation of metal sulfide phases as well as the complexation of the metals by sulfide and other sulfur species. Stability constants of a variety of metals of environmental significance with sulfide, thiosulfate and polysulfides will be determined. The constants will be obtained by voltammetric methods using the peaks of the sulfur species and/or the metal. The research also requires titrations of the complexes with acid and base to determine the number of protons attached to the sulfur species. This work will build on initial work in seawater which shows that iron (II) and sulfide form two complexes which are Fe(SH)+ (log B=5.5) and Fe2(SH)3+ (log B= 11.1). These constants are orders of magnitude higher than constants evaluated by linear free energy relationships. In fact, Fe2(SH)3+ was not predicted by this or any experimental approach which uses sulfide as a titrant. Thus, Fe(II) solubility at anoxic interfaces and in sulfidic environments can be enhanced over previous estimates.