Evaluation of Electrokinetic Remediation of Arsenic-contaminated Soils

Abstract

The potential of electrokinetic (EK) remediation technology has been successfully demonstrated for the remediation of heavy metal-contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic from two soil samples; a kaolinite soil artificially contaminated with arsenic and an arsenic-bearing tailing-soil taken from the Myungbong (MB) gold mine area. The effectiveness of enhancing agents was investigated using three different types of cathodic electrolytes; deionized water (DIW), potassium phosphate (KH(2)PO(4)) and sodium hydroxide (NaOH). The results of the experiments on the kaolinite show that the potassium phosphate was the most effective in extracting arsenic, probably due to anion exchange of arsenic species by phosphate. On the other hand, the sodium hydroxide seemed to be the most efficient in removing arsenic from the tailing-soil. This result may be explained by the fact that the sodium hydroxide increased the soil pH and accelerated ionic migration of arsenic species through the desorption of arsenic species as well as the dissolution of arsenic-bearing minerals.

Waste Treatment and Remediation Technologies for Arsenic

“…Many of these electrokinetic techniques are also energy intensive and complicated (Cundy and Hopkinson, 2005), which hinders their commercialization. Kim, Kim and Kim (2005) evaluated the treatment of arsenic in two fine-grained soils with an ex situ electrokinetic technology, which consisted placing the samples in a three-compartment chamber with a platinum anode and titanium cathode on opposite ends. One soil consisting of a Korean kaolinite was spiked with 1500 mg kg −1 of As(V).…”

Ex-Situ Remediation Technologies for Environmental Pollutants: A Critical Perspective

“…Similarly, Awual et al ( 2011Awual et al ( , 2013 reported that ion-exchange resins, polyallylamine fi bres and primary amine could selectively take up phosphate and As(V) from contaminated groundwater systems at higher fl ow rates even in the presence of competing anions such as sulphate, bicarbonate, nitrate and chloride. Kim et al ( 2005 ) studied the effect of ion-exchange membrane (IEM)-enhanced electrokinetic (EK) soil processing on metal removal, and observed that nearly 96 % Cd and Pb was removed by this integrated mechanism within 4 days. One limitation of EK remedial system alone (soil hydroxide is precipitated near the cathodic side of the electrodes) was overcome by the use of IEMs.…”

Mathematical Modeling and Sensitivity Analysis on Cadmium Transport in Kaolinite under Direct Current Electric Field

“…Various methods including bioremediation, thermal remediation, soil vapor extraction, soil washing, soil flushing, electrokinetic remediation (EKR) have been introduced to purify contaminated lands [1]. Among them, EKR has shown to be a practical method to remedy low permeable soils (e.g., clays and silts) [2][3][4][5][6]. In the EKR process, application of low direct current (DC) into the soil medium leads to contaminants transportation by different transport phenomena such as electro-migration, electroosmotic flow, and electrophoresis.…”