Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do, Republic of Korea.
Environ Sci Pollut Res Int. 2015 Jul;22(13):9912-21. doi: 10.1007/s11356-015-4155-x. Epub 2015 Feb 7.
In this study, the feasibility of an ex situ electrokinetic (EK) process combined with pre-oxidation using hydrogen peroxide (H2O2) and pre-washing using ethylenediaminetetraacetic acid (EDTA) was investigated in enhancing the extraction of Cu, Pb, and Zn from actual dredged harbor sediment. H2O2 pre-oxidation led to a change in the fractionation of Cu bound to organic matter and the sulfide fraction in the Fe-Mn oxides to the exchangeable fraction, but was not effective at removing metals. In contrast, EDTA pre-washing changed the Fe-Mn oxide-bound fractions of Cu and Pb into easily extractable fractions; 20.1, 27.5, and 32.8% of Cu, Pb, and Zn were removed, respectively. During EK treatment, metals were transported toward the anode by electromigration of negatively charged complexes such as metal-EDTA and metal-citrate. However, EK treatment did not significantly enhance the removal of metals because metals accumulated near the anodic region with an increase in the exchangeable fraction due to the short EK operating duration and low voltage gradient. Therefore, it is necessary to extend the EK operating duration and/or increase the voltage gradient for effective transportation and removal of metals from sediment.
在这项研究中，研究了在原地电动（EK）过程中结合使用过氧化氢（H2O2）预氧化和乙二胺四乙酸（EDTA）预洗，以增强从实际疏浚港口沉积物中提取 Cu、Pb 和 Zn 的可行性。H2O2 预氧化导致与有机物结合的 Cu 和 Fe-Mn 氧化物中硫化物部分的分馏发生变化，转化为可交换部分，但对去除金属没有效果。相比之下，EDTA 预洗将 Cu 和 Pb 的 Fe-Mn 氧化物结合部分转化为易于提取的部分；分别去除了 20.1%、27.5%和 32.8%的 Cu、Pb 和 Zn。在 EK 处理过程中，带负电荷的配合物（如金属-EDTA 和金属-柠檬酸盐）通过电迁移将金属向阳极输送。然而，EK 处理并没有显著提高金属的去除率，因为由于 EK 操作时间短和电压梯度低，可交换部分的增加导致金属在阳极区域附近积累。因此，需要延长 EK 操作时间和/或增加电压梯度，以有效地从沉积物中输送和去除金属。
