Fu Rong-Bing, Liu Fang, Ma Jin, Zhang Chang-Bo, He Guo-Fu
Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
Huan Jing Ke Xue. 2012 Jan;33(1):280-5.
Electrokinetic transport processes have been shown to have potential for the effective removal of heavy metals from soils. However, pH changes near the anode and cathode limit their widespread application in the remediation of contaminated soils. Permeable reactive composite electrodes (PRCE) were made by attaching reactive materials such as Fe(0) and zeolite to the electrodes, and the effects of the composite electrodes on pH control, chromium removal efficiency and Cr speciation changes were studied in the electrokinetic remediation process of Cr( VI) contaminated soil. Composite electrodes consisting of permeable reactive materials gave better pH control and Cr removal efficiency compared to traditional electrodes, and a Fe(0) + zeolite reactive layer in the anode exhibited the best performance compared to zeolite or Fe(0) alone. After 5 days of electrokinetic remediation with a DC voltage of 2 V x cm(-1), the Fe(0) + zeolite reactive layer lowered the pH fluctuation, maintained the soil pH in the range of 5.5 to 8.5, raised the Cr(VI) removal efficiency up to 97% in any soil section, produced lower Cr(III) residues, enhanced the amount of Cr retention up to 8 and 1.8 times respectively, and transformed 98% of the Cr(VI) into lower toxicity Cr(III). This study provides a theoretical basis for the exploitation of permeable reactive composite electrodes which are a practical option for future applications.
电动传输过程已被证明在有效去除土壤中的重金属方面具有潜力。然而，阳极和阴极附近的pH值变化限制了它们在污染土壤修复中的广泛应用。通过将诸如Fe(0)和沸石等活性材料附着到电极上制备了可渗透反应性复合电极（PRCE），并在Cr(VI)污染土壤的电动修复过程中研究了复合电极对pH值控制、铬去除效率和Cr形态变化的影响。与传统电极相比，由可渗透反应性材料组成的复合电极具有更好的pH值控制和铬去除效率，并且阳极中的Fe(0)+沸石反应层与单独的沸石或Fe(0)相比表现出最佳性能。在以2 V x cm(-1)的直流电压进行5天的电动修复后，Fe(0)+沸石反应层降低了pH值波动，将土壤pH值维持在5.5至8.5范围内，在任何土壤区域将Cr(VI)去除效率提高到97%，产生了较低的Cr(III)残留量，分别将Cr保留量提高了8倍和1.8倍，并将98%的Cr(VI)转化为毒性较低的Cr(III)。本研究为开发可渗透反应性复合电极提供了理论基础，这种电极是未来实际应用的一个可行选择。
