Buchireddy Prashanth R, Bricka R Mark, Gent David B
Mississippi State University, Dave C. Swalm School of Chemical Engineering, Mississippi State, MS, USA.
J Hazard Mater. 2009 Feb 15;162(1):490-7. doi: 10.1016/j.jhazmat.2008.05.092. Epub 2008 May 23.
As a result of wood treatment, and the recent banning of the copper, chromium, and arsenic (CCA) treated wood for residential use many CCA treatment facilities have been abandoned or being closed. Soil contamination resulting from CCA is common at these sites. In this study, the feasibility of electrokinetic technique to remove CCA from contaminated soil was investigated. To better understand the ionic mobility within the soil and to detect the generation and advancement of acid front, sampling ports were provided along the longitudinal axis of a test cell. To determine the effect of varying current, three tests were performed at different current densities of 5.9, 2.9, and 1.5mA/cm(2) for a period of 15 days. The initial concentrations of copper, chromium, and arsenic in the soil were 4800, 3100, and 5200mg/kg, respectively. Dilute nitric acid was used as an amendment to neutralize the hydroxyl ions produced at the cathode. Experiments resulted in removal efficiencies as high as 65% for copper, 72% for chromium, and 77% for arsenic. The results also indicated that the advancement of acid front favored desorption of metals from the soil and the metals were mobilized either as free cations or metal complexes. Chromium that was in its +6 valence state was transported as anion prior to its reduction. However, once the chromium was reduced to chromium(III) its transport direction reversed with transport being favored towards the cathode.
由于木材处理以及近期禁止将铜铬砷（CCA）处理过的木材用于住宅用途，许多CCA处理设施已被废弃或即将关闭。这些场地普遍存在CCA造成的土壤污染。在本研究中，对电动技术从污染土壤中去除CCA的可行性进行了研究。为了更好地了解土壤中的离子迁移率并检测酸前沿的产生和推进情况，在测试单元的纵轴上设置了采样端口。为了确定不同电流的影响，在5.9、2.9和1.5mA/cm²的不同电流密度下进行了三项测试，持续15天。土壤中铜、铬和砷的初始浓度分别为4800、3100和5200mg/kg。使用稀硝酸作为改良剂来中和阴极产生的氢氧根离子。实验结果表明，铜的去除效率高达65%，铬为72%，砷为77%。结果还表明，酸前沿的推进有利于金属从土壤中解吸，金属以游离阳离子或金属络合物的形式被 mobilized。处于+6价态的铬在还原之前以阴离子形式迁移。然而，一旦铬被还原为铬（III），其迁移方向就会反转，向阴极方向的迁移更为有利。 （注：“mobilized”此处可能有误，推测原文可能是“mobilized”，暂按此翻译，如有准确原文可进一步修正）
