Abstract
Electrokinetic remediation (also known as electrokinetics) is a promising technology for removing metals from fine-grained soils. However, few studies have been conducted regarding the transport behavior of multi-metals during electrokinetics. We investigated the transport of As, Cu, Pb, and Zn from soils during electrokinetics, the metal fractionation before and after electrokinetics, the relationships between metal transport and fractionation, and the effects of electrolyte conditioning. The main transport mechanisms of the metals were electroosmosis and electromigration during the first two weeks and electromigration during the following weeks. The direction of electroosmotic flow was from the anode to the cathode, and the metals in the dissolved and reducible-oxides fractions were transported to the anode or cathode by electromigration according to the chemical speciation of the metal ions in the pore water. Moreover, a portion of the metals that were initially in the residual fraction transitioned to the reducible and soluble fractions during electrokinetic treatment. However, this alteration was slow and resulted in decreasing metal removal rates as the electrokinetic treatment progressed. In addition, the use of NaOH, H3PO4, and Na2SO4 as electrolytes resulted in conditions that favored the precipitation of metal hydroxides, phosphates, and sulfates in the soil. These results demonstrated that metal removal was affected by the initial metal fractionation, metal speciation in the pore solution, and the physical-chemical parameters of the electrolytes, such as pH and electrolyte composition. Therefore, the treatment time, use of chemicals, and energy consumption could be reduced by optimizing pretreatment and by choosing appropriate electrolytes for the target metals.
| Original language | English |
|---|---|
| Pages (from-to) | 79-86 |
| Number of pages | 8 |
| Journal | Chemosphere |
| Volume | 117 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2014 Jan 1 |
| Externally published | Yes |
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Keywords
- Arsenic
- Electrokinetics
- Electromigration
- Electroosmosis
- Sequential extraction
ASJC Scopus subject areas
- Environmental Chemistry
- Chemistry(all)
Cite this
The transport behavior of As, Cu, Pb, and Zn during electrokinetic remediation of a contaminated soil using electrolyte conditioning. / Yang, Jung Seok; Kwon, Man Jae; Choi, Jaeyoung; Baek, Kitae; O'Loughlin, Edward J.
In: Chemosphere, Vol. 117, No. 1, 01.01.2014, p. 79-86.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The transport behavior of As, Cu, Pb, and Zn during electrokinetic remediation of a contaminated soil using electrolyte conditioning
AU - Yang, Jung Seok
AU - Kwon, Man Jae
AU - Choi, Jaeyoung
AU - Baek, Kitae
AU - O'Loughlin, Edward J.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - Electrokinetic remediation (also known as electrokinetics) is a promising technology for removing metals from fine-grained soils. However, few studies have been conducted regarding the transport behavior of multi-metals during electrokinetics. We investigated the transport of As, Cu, Pb, and Zn from soils during electrokinetics, the metal fractionation before and after electrokinetics, the relationships between metal transport and fractionation, and the effects of electrolyte conditioning. The main transport mechanisms of the metals were electroosmosis and electromigration during the first two weeks and electromigration during the following weeks. The direction of electroosmotic flow was from the anode to the cathode, and the metals in the dissolved and reducible-oxides fractions were transported to the anode or cathode by electromigration according to the chemical speciation of the metal ions in the pore water. Moreover, a portion of the metals that were initially in the residual fraction transitioned to the reducible and soluble fractions during electrokinetic treatment. However, this alteration was slow and resulted in decreasing metal removal rates as the electrokinetic treatment progressed. In addition, the use of NaOH, H3PO4, and Na2SO4 as electrolytes resulted in conditions that favored the precipitation of metal hydroxides, phosphates, and sulfates in the soil. These results demonstrated that metal removal was affected by the initial metal fractionation, metal speciation in the pore solution, and the physical-chemical parameters of the electrolytes, such as pH and electrolyte composition. Therefore, the treatment time, use of chemicals, and energy consumption could be reduced by optimizing pretreatment and by choosing appropriate electrolytes for the target metals.
AB - Electrokinetic remediation (also known as electrokinetics) is a promising technology for removing metals from fine-grained soils. However, few studies have been conducted regarding the transport behavior of multi-metals during electrokinetics. We investigated the transport of As, Cu, Pb, and Zn from soils during electrokinetics, the metal fractionation before and after electrokinetics, the relationships between metal transport and fractionation, and the effects of electrolyte conditioning. The main transport mechanisms of the metals were electroosmosis and electromigration during the first two weeks and electromigration during the following weeks. The direction of electroosmotic flow was from the anode to the cathode, and the metals in the dissolved and reducible-oxides fractions were transported to the anode or cathode by electromigration according to the chemical speciation of the metal ions in the pore water. Moreover, a portion of the metals that were initially in the residual fraction transitioned to the reducible and soluble fractions during electrokinetic treatment. However, this alteration was slow and resulted in decreasing metal removal rates as the electrokinetic treatment progressed. In addition, the use of NaOH, H3PO4, and Na2SO4 as electrolytes resulted in conditions that favored the precipitation of metal hydroxides, phosphates, and sulfates in the soil. These results demonstrated that metal removal was affected by the initial metal fractionation, metal speciation in the pore solution, and the physical-chemical parameters of the electrolytes, such as pH and electrolyte composition. Therefore, the treatment time, use of chemicals, and energy consumption could be reduced by optimizing pretreatment and by choosing appropriate electrolytes for the target metals.
KW - Arsenic
KW - Electrokinetics
KW - Electromigration
KW - Electroosmosis
KW - Sequential extraction
UR - http://www.scopus.com/inward/record.url?scp=84908458169&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84908458169&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2014.05.079
DO - 10.1016/j.chemosphere.2014.05.079
M3 - Article
C2 - 24972074
AN - SCOPUS:84908458169
VL - 117
SP - 79
EP - 86
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
IS - 1
ER -