College of Science and Technology, Department of Biochemistry, Chemistry and Physics, University of Central Missouri, Warrensburg, MO 64093, USA.
Chemosphere. 2010 Mar;78(11):1295-300. doi: 10.1016/j.chemosphere.2010.01.020. Epub 2010 Feb 2.
Ultrasonic extraction (UE) was used to estimate the total bioaccessible fractions of arsenic and selenium released from rocks associated with mountaintop removal/valley fill coal mining. The combined readily bioaccessible amounts of arsenic and selenium in water soluble, exchangeable and NaOH fractions can be extracted from the solid phase within a 20 or 25 min application of 200 W cm(-2) ultrasound energy in nanopure water for selenium and arsenic, respectively. Application of a two-way ANOVA predicted that there are no significant differences (p0.001, n=12) in the extracted arsenic and selenium concentrations between the combined bioaccessible and ultrasonic extracts. The mechanisms for the UE of arsenic and selenium are thought to involve the formation of secondary minerals on the particle surfaces which eventually dissolve with continued sonication. This is supported by the presence of transient Si-O stretching and OH absorption and bending ATR-FTIR peaks at 795.33 cm(-1), 696.61 cm(-1) and 910.81 cm(-1). The subsequent dissolution of secondary minerals is followed by the release of chemical species that include selenium and arsenic. Release rates decrease after the ultrasound energy elastic limit for the particles is reached. Selenium and arsenic are bound differently within the rock lattice because no selenium was detected in the acid soluble fraction and no arsenic was found in the exchangeable fraction. However, selenium was found in the exchangeable fraction and arsenic was found in the acid soluble fraction. The characterization of coal associated rocks is essential to the design of methodologies and procedures that can be used to control the release of arsenic and selenium from valley fills.
超声萃取 (UE) 被用于估计从与露天采矿/山谷填充相关的岩石中释放的砷和硒的总生物可利用分数。在 200 W cm(-2) 的超声能量下，分别在纳米纯水中应用 20 或 25 分钟，可以从固相中提取出水中可溶、可交换和 NaOH 部分中砷和硒的组合易生物利用量。双向方差分析的应用预测，在组合生物可利用和超声提取物中，砷和硒的提取浓度没有显著差异（p0.001，n=12）。认为砷和硒的 UE 机制涉及在颗粒表面形成次生矿物，这些矿物最终会随着连续的超声作用而溶解。这得到了瞬态 Si-O 伸缩和 OH 吸收和弯曲 ATR-FTIR 峰在 795.33 cm(-1)、696.61 cm(-1)和 910.81 cm(-1)处的存在的支持。随后，次生矿物的溶解伴随着包括硒和砷在内的化学物质的释放。当颗粒的超声能量弹性极限达到时，释放速率会降低。硒和砷在岩石晶格中的结合方式不同，因为在酸可溶部分中未检测到硒，在可交换部分中也未发现砷。然而，在可交换部分中发现了硒，在酸可溶部分中发现了砷。与煤相关的岩石的特征对于设计可以用于控制山谷填充中砷和硒释放的方法和程序是必不可少的。
