Development of Advanced In-situ Soil Remediation Method

电渗和离子迁移的动电土壤修复仅限于可溶性物质。在较高的pH值下，土壤颗粒吸附更多的重金属，如镉，比在较低的pH值和促进重金属的沉淀反应。这两种机制都使重金属无法移动，使清理更加困难，电动提取效率低下。因此，土壤酸化对提高电动法去除重金属污染土壤中镉的效率具有重要意义。同时，六价铬具有更强的移动的性和易溶性。六价铬在水中具有高溶解度，并且根据溶液的pH以铬酸根、单铬酸根或重铬酸根阴离子存在。这种六价铬是需要补救的化学形式。在此基础上，采用一种简单的电流与水力耦合的数值方法，对非饱和土壤中氢离子和镉离子的迁移进行了数值模拟，并对模拟结果进行了分析。 ...更多信息 ic流，和非饱和土的处理进行了研究。在这项研究中，镉和六价铬的迁移预测与一个简单的数值方法，其中电流耦合与水力流动，并在土壤中的吸附过程中引起的模型。研究结果表明：与一维电极结构相比，三维电极结构对镉的去除效果更好。同时，在去除土壤中六价铬时，与一维电极结构相比，三维电极结构可以有效地去除土壤中的六价铬。较大的电极间距增加了所需的处理时间，并且还发现较大的电场强度减少了所需的处理时间。氢和镉离子在非饱和土壤中向下迁移，特别是在上层桑迪/粘土和下层粘土/粉土中向下迁移显著。然而，修复成功地应用于非饱和土壤耦合电-水力梯度。少

Electrokinetic soil remediation by electroosmosis and ionic migration is restricted to soluble substances. At a higher pH, the soil particles sorb more heavy metals, such as cadmium, than at a lower pH and the precipitation reactions of heavy metals are promoted. Both mechanisms make heavy metals immobile, rendering cleanup more difficult and electrokinetic extraction inefficient. Therefore, the acidification of soils is very important to increase the cleanup efficiencies of heavy metals, such as cadmium by electrokinetic method from contaminated soils. Meanwhile, hexavalent chromium is more mobile and easily soluble. Hexavalent chromium has high solubility in water and exists as chromate, monochromate or dichromate anions depending on the pH of the solutions. This hexavalent chromium is the chemical form requiring remediation. And then, hydrogen and cadmium ions transport in unsaturated soils are predicted with a simple numerical method in which electrical flow is coupled with hydraul … More ic flow, and the treatment for unsaturated soils are investigated. In this study, cadmium and hexavalent chromium transport are predicted with a simple numerical method in which electrical flow is coupled with hydraulic flow, and the sorption process in the soils is induced in the model. The results obtained this study are summarized as follows :The two-dimensional electrode configurations containing cathode surrounded by three or more anodes rapidly remove cadmium from soils compared with one-dimensional electrode configuration. Meanwhile, in the removal of hexavalent chromium from soils, the two-dimensional electrode configurations containing anode surrounded by three or more cathodes can be effectively utilized compared with one-dimensional electrode configuration. A larger electrode spacing increases the processing time required, and it was also found that a larger electric field strength reduced the processing time required. Hydrogen and cadmium ions move downward in unsaturated soils, particularly, move significantly downward against upper layer, sandy/clay, and lower layer, clayey/silty soils. However, remediation is applied successfully to unsaturated soils by coupled electric-hydraulic gradient. Less