Institute for Materials Research, Graduate School of Environmental Studies, Tohoku University, Sendai 980-8577, Japan.
Chemosphere. 2011 Oct;85(4):598-602. doi: 10.1016/j.chemosphere.2011.06.099. Epub 2011 Jul 23.
Coal fly ash emitted from coal-fired electric power stations generally contains environmentally regulated trace elements. In particular, boron, arsenic, and selenium have been recognized as troublesome trace elements because elutions from the fly ash contain them. In order to design an effective removal process for these trace elements, we have developed and investigated an acid-washing process. The dissolution behavior of selenium from coal fly ash particles was focused on for the improvement of the process, and was found to greatly depend on the pH of the acid solutions. The species of selenium in solutions with a pH of around 0-1 was determined to be H2SeO3. The dissolved H2SeO3 transformed into HSeO3- and adsorbed onto the surface of the ash particles in solution upon elevation of the pH. The re-elution of the absorbed HSeO3- as SeO3(2-) at a pH of 10 was also confirmed, and will cause the elution of the excess selenium from the acid-washed ash.
燃煤火力发电站排放的粉煤灰通常含有环境法规规定的微量元素。特别是硼、砷和硒已被认为是有害的微量元素，因为粉煤灰中的浸出液含有这些元素。为了设计一种有效的去除这些微量元素的方法，我们开发并研究了一种酸洗工艺。重点研究了硒从粉煤灰颗粒中的溶解行为，发现其极大地取决于酸溶液的 pH 值。在 pH 值约为 0-1 的溶液中，硒的形态被确定为 H2SeO3。当 pH 值升高时，溶解的 H2SeO3 转化为 HSeO3-并吸附在溶液中灰分颗粒的表面上。在 pH 值为 10 时，也证实了被吸附的 HSeO3-可以重新洗脱为 SeO3(2-)，这将导致过量的硒从酸洗后的灰分中洗脱出来。
