Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA.
Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA.
J Hazard Mater. 2016 Apr 15;307:184-92. doi: 10.1016/j.jhazmat.2016.01.001. Epub 2016 Jan 6.
Several studies have demonstrated the ability of drinking water treatment residuals (WTRs) to efficiently sorb metal cations from aqueous solutions. Reported results have stimulated interest on the potential use of WTRs as sorbent for metal removal from contaminated aqueous effluents as well as in metal immobilization in contaminated soils. However, knowledge on mechanisms of metal sorption by WTRs remains very limited and data on the long-term stability of formed metal-WTR complexes as a function of changing key environmental parameters are lacking. In this study, chemical selective sequential extraction (SSE), scanning electron microscopy combined with X-ray energy dispersive spectrometer (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were used to gain insight into the different mechanisms of mercury (Hg) binding to aluminum based WTR (Al-WTRs). Results from sorption studies show that a significant portion of Hg becomes incorporated in the operationally defined residual fraction of Al-WTRs, and therefore, not prone to dissolution and mobility. The results of solid phase analyses suggested that Hg immobilization by Al-WTR occurs largely through its binding to oxygen donor atoms of mineral ligands driven by a combination of electrostatic forces and covalent bonding.
几项研究已经证明，饮用水处理残渣（WTRs）能够有效地从水溶液中吸附金属阳离子。已有的研究结果激发了人们对 WTRs 作为吸附剂从受污染的水废水中去除金属以及在受污染的土壤中固定金属的潜在应用的兴趣。然而，WTRs 对金属的吸附机制的知识仍然非常有限，并且缺乏关于形成的金属-WTR 配合物在不断变化的关键环境参数下的长期稳定性的数据。在这项研究中，化学选择性顺序提取（SSE）、扫描电子显微镜结合 X 射线能量色散光谱（SEM-EDS）和 X 射线光电子能谱（XPS）被用于深入了解汞（Hg）与基于铝的 WTR（Al-WTRs）结合的不同机制。吸附研究的结果表明，相当一部分的 Hg 被结合到 Al-WTRs 的操作定义的残余部分中，因此不易溶解和迁移。固相分析的结果表明，Al-WTRs 对 Hg 的固定主要是通过静电和共价键的组合作用，使其与矿物配体的供氧原子结合。
