Electrokinetic removal of chromium and copper from contaminated soils by lactic acid enhancement in the catholyte

Abstract： The electrokinetic removal of chromium and copper from contaminated soils by adding lactic acid in cathode chamber as an enhancing reagent was evaluated. Two sets of duplicate experiments with chromium contaminated kaolinite and with a silty soil sampled from a superfund site in California of USA and polluted by Cr and Cu, were carried out in a constant current mode. Changes of soil water content and soil pH before and after the electrokinetic experiments, and variations of voltage drop and electroosmosis flow during the treatments were examined. The results indicated that Cr, spiked as Cr(Ⅵ) in the kaolinite, was accumulated mainly in the anode chamber, and some of Cr and metal hydroxides precipitated in the soil sections in contact with the cathode, which significantly increased electrical energy consumption. Treatment of the soil collected from the site showed accumulation of large amounts of Cr and Cu in the anode chamber while none was detected in the cathode one. The results suggested that the two metals either complexed with the injected lactic acid at the cathode or existed as negatively charged complex, and electromigrated toward the anode under a voltage gradient. 作 者： ZHOU Dong-mei    Alshawabkeh Akram N    DENG Chang-fen    CANG Long    SI You-bin   作者單位： ZHOU Dong-mei(State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China;Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts, USA)

Alshawabkeh Akram N(Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts, USA)

DENG Chang-fen,CANG Long,SI You-bin(State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China) 

期 刊： 環境科學學報(英文版)  ISTICSCI   Journal： JOURNAL OF ENVIRONMENTAL SCIENCES  年，卷(期)： 2004, 16(4)  分類號： X131.3  Keywords： electrokinetic remediation    metal    soil    lactic acid