Gustin Mae Sexauer, Ladwig Kenneth
Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, Nevada 89557, USA.
J Air Waste Manag Assoc. 2004 Mar;54(3):320-30. doi: 10.1080/10473289.2004.10470900.
Some mercury (Hg) naturally present in coal is retained in the fly ash remaining after combustion. Concern has been raised regarding the potential for release of this Hg to the environment. The exchange of Hg between fly ash and the atmosphere was measured in the laboratory and in situ at a fly ash landfill. All samples of fly ash used in the laboratory study, with the exception of that derived from lignite-type coal, acted as a sink for atmospheric Hg. Deposition rates were found to increase as air Hg concentrations increased and to decrease with incident light and increased temperature. Addition of water to fly ash samples resulted in re-emission of deposited atmospheric Hg. Deposition was the dominant flux measured in situ at a fly ash landfill. Atmospheric Hg was deposited to all samples collected as part of two demonstration projects using carbon injection for enhanced Hg capture. Hg concentrations of extracts derived using U.S. Environmental Protection Agency Method 1312 (Synthetic Precipitation Leaching Procedure) were < or = 14.4 ng/L. Data developed demonstrate that fly ash, including that collected from Hg removal projects, will release little Hg to the air or water, and under certain conditions, absorbs Hg from the air.
煤中天然存在的一些汞（Hg）会保留在燃烧后剩余的飞灰中。人们对这种汞向环境释放的可能性表示担忧。在实验室和飞灰填埋场现场测量了飞灰与大气之间汞的交换情况。实验室研究中使用的所有飞灰样品，除了来自褐煤型煤的飞灰外，都充当了大气汞的汇。发现沉积速率随着空气中汞浓度的增加而增加，并随着入射光和温度的升高而降低。向飞灰样品中加水会导致沉积的大气汞重新排放。在飞灰填埋场现场测量时，沉积是主要的通量。作为两个使用碳注入增强汞捕获的示范项目的一部分，大气汞沉积到所有收集的样品中。使用美国环境保护局方法1312（合成沉淀浸出程序）得到的提取物中的汞浓度≤14.4 ng/L。所获得的数据表明，飞灰，包括从汞去除项目收集的飞灰，向空气或水中释放的汞很少，并且在某些条件下会从空气中吸收汞。
