Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020, USA.
Water Res. 2011 Nov 1;45(17):5441-8. doi: 10.1016/j.watres.2011.08.003. Epub 2011 Aug 11.
This study investigated the role of dissolved organic matter on mercury partitioning between a hydrophobic surface (polyethylene, PE) and a reduced sulfur-rich surface (polysulfide rubber, PSR). Comparative sorption studies employed polyethylene and polyethylene coated with PSR for reactions with DOM-bound mercuric ions. These studies revealed that PSR enhanced the Hg-DOM removal from water when DOM was Suwannee River natural organic matter (NOM), fulvic acid (FA), or humic acid (HA), while the same amount of 1,3-propanedithiol-bound mercuric ion was removed by both PE and PSR-PE. The differences for Hg-DOM removal efficiencies between PE and PSR-PE varied depending on which DOM was bound to mercuric ion as suggested by the PE/water and PSR-PE/water partition coefficients for mercury. The surface concentrations of mercury on PE and PSR-PE with the same DOM measured by x-ray photoelectron spectroscopy were similar, which indicated the comparable amounts of immobilized mercury on PE and PSR-PE being exposed to the aqueous phase. With these observations, two major pathways for the immobilization reactions between PSR-PE and Hg-DOM were examined: 1) adsorption of Hg-DOM on PE by hydrophobic interactions between DOM and PE, and 2) addition reaction of Hg-DOM onto PSR by a complexation reaction between Hg and PSR. The percent contribution of each pathway was derived from a mass balance and the ratios among aqueous mercury, PE-bound Hg-DOM, and PSR-bound Hg-DOM concentrations. The results indicate strong binding of mercuric ion with both dissolved organic matter and PSR polymer. The FT-IR examination of Hg-preloaded-PSR-PEs after the reaction with DOM corroborated a strong interaction between mercuric ion and 1,3-propanedithiol compared to Hg-HA, Hg-FA, or Hg-NOM interactions.
本研究探讨了溶解有机质在疏水性表面（聚乙烯，PE）和富含还原硫的表面（多硫化橡胶，PSR）之间分配汞的作用。比较吸附研究采用聚乙烯和涂覆有 PSR 的聚乙烯与 DOM 结合的汞离子进行反应。这些研究表明，当 DOM 为苏万尼河天然有机物 (NOM)、富里酸 (FA) 或腐殖酸 (HA) 时，PSR 增强了 Hg-DOM 从水中的去除，而相同量的 1,3-丙二硫醇结合的汞离子被 PE 和 PSR-PE 去除。PE 和 PSR-PE 之间 Hg-DOM 去除效率的差异取决于哪种 DOM 与汞离子结合，这是由汞在 PE 和 PSR-PE 中的水分配系数所表明的。通过 X 射线光电子能谱测量的具有相同 DOM 的 PE 和 PSR-PE 上的汞表面浓度相似，这表明暴露于水相的 PE 和 PSR-PE 上固定的汞量相似。根据这些观察结果，研究了 PSR-PE 与 Hg-DOM 之间的固定化反应的两种主要途径：1）DOM 与 PE 之间的疏水相互作用将 Hg-DOM 吸附在 PE 上，2）Hg-DOM 与 PSR 通过 Hg 和 PSR 之间的络合反应添加到 PSR 上。每种途径的贡献百分比是从质量平衡和水相中汞、PE 结合的 Hg-DOM 和 PSR 结合的 Hg-DOM 浓度之间的比值推导出来的。结果表明，汞离子与溶解有机质和 PSR 聚合物均具有很强的结合能力。与 Hg-HA、Hg-FA 或 Hg-NOM 相互作用相比，对反应后与 DOM 反应的 Hg 预加载 PSR-PE 的傅里叶变换红外 (FT-IR) 检查证实了 Hg 与 1,3-丙二硫醇之间的强烈相互作用。
