Electrokinetic Remediation of Cadmium-Contaminated Clay

Yeung, Albert T.; Hsu, Cheng-non

doi:10.1061/(asce)0733-9372(2005)131:2(298)

Cited by 92 publications

(58 citation statements)

References 15 publications

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“…Thus, the direction of anion migration is dependent on the direction of the resultant of these opposite movements. If reverse electroosmotic flow occurs, i.e., from the cathode toward the anode, the situations are reversed (Yeung and Hsu 2005). Electroosmosis and ionic migration move anions toward the anode, and the direction of cation migration is dependent on the direction of the resultant of the two opposite movements.…”

Section: Conceptual Modelingmentioning

confidence: 99%

Electrokinetic extraction of lead from kaolinites: I. Numerical modeling

Yeung

Hsu²,

Menon³

2011

Environmentalist

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Experimental results obtained to date indicate electrokinetic extraction is viable in removing organic and inorganic contaminants from fine-grained soils. However, electrochemical reactions and soil-contaminant interactions that occur simultaneously may enhance or reduce the removal efficiency of the hazardous waste site remediation process. Many sites worldwide are contaminated by lead and its compounds, resulting in lead poisoning. It is difficult to remove lead from fine-grained soil because of the existence of a great variety of lead complexes and their pH-dependent and reversible physicochemical properties. The feasibility of electrokinetic extraction of lead from kaolinites is investigated theoretically, numerically, and experimentally in this study. This is the first paper of two companion papers presenting the theoretical and numerical modeling of the transport of lead species, and electrochemical reactions and soil-contaminant interactions occurring during the electrokinetic extraction process. The comparison between simulation results and experimental results is presented in the second paper.

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Section: Conceptual Modelingmentioning

confidence: 99%

Electrokinetic extraction of lead from kaolinites: I. Numerical modeling

Yeung

Hsu²,

Menon³

2011

Environmentalist

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“…In order to enhance the mobility and removal of heavy metals in electric fields, several techniques have been applied to electrokinetic systems, such as control of the pH of the electrolyte to prevent metal-hydroxide precipitation [19][20][21][22], use of various chelating reagents [7,9], ionexchange membranes [13,20], the polarity exchange technique [23], and pulsed voltage [19,24,25]. In this study, a pulsed power supply was used to increase extraction of heavy metals from the soil surface and to decrease polarization and electrical energy consumption by periodically supplying an electric field [19].…”

Section: Introductionmentioning

confidence: 99%

“…Electrokinetic remediation is a promising technique for various low permeability matrixes, including silty/clayey soils, mine tailings, saline soils, industrial sites, harbor sediments, sewage sludge, and treated wood contaminated with heavy metals, mixed inorganic species, and organic pollutants [3][4][5][6][7][8][9][10][11][12][13][14][15]. In electrokinetic remediation systems, charged species migrate toward anodes and cathodes through electro-migration, electro-osmotic flow, electrophoresis, and diffusion [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Pulsed electrokinetic removal of Cd and Zn from fine-grained soil

et al. 2009

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Pulsed electrokinetics studies were carried out to optimize the removal of Zn and Cd from fine-grained soils and to observe the effects of varying the pulse frequency, pulse time ratio (on/off), and DC voltage gradient. Existing forms of heavy metals in the soil matrix were determined using a sequential extraction method. The strongly bound fraction (bound to organic matter and residuals) that is difficult to remove from the soil matrix comprised 74 and 62% of the total Zn and Cd, respectively. In the electrokinetic remediation experiments, MgSO 4 was employed to increase the ionic strength of the soil for 2 weeks. Transportation of heavy metals was influenced by the frequency, pulse ratio, and the voltage gradient of the pulsed electric field. Extraction efficiency of Zn and Cd near the anode was correlated positively with the voltage gradient at a given pulse and ratio. A high pulse frequency (1,800 cycles/h) enhanced the removal efficiency of the heavy metals compared to a low pulse frequency (1,200 cycles/h) at a supplied voltage gradient of 1 V/cm. Although pulsed electrokinetics was more effective in extracting and desorbing ions near the anode than conventional electrokinetics, its ability to transport heavy metals from the anode to the cathode was relatively small. Total removals with pulsed electrokinetics were 21-31% for Zn and 18-24% for Cd. In summary, pulsed electrokinetics can enhance removal efficiency of heavy metals and is beneficial with regard to electrical energy consumption.

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“…Pertinent physicochemical properties of the two kaolinites are tabulated in Table 1 of the first paper of these two companion papers. More detailed descriptions of the soils are given by Yeung et al (1996), Yeung and Hsu (2005).…”

Section: Soil Propertiesmentioning

confidence: 99%

“…The technique of electrokinetic extraction has been applied successfully in laboratory bench-scale experiments to mobilize and to remove organic contaminants such as phenol (Acar et al 1992;Shapiro and Probstein 1993;Gopinath 1994;Yang and Long 1999) and gasoline hydrocarbons (Bruell et al 1992;Maini et al 2000); and inorganic contaminants such as Cu(II), Pb(II), Hg(II), and Cd(II) (Hamed et al 1991;Pamukcu and Wittle 1992;Eykholt and Daniel 1994;Yeung et al 1996;Sawada et al 2003;Suèr and Allard 2003;Yeung and Hsu 2005) spiked in clayey soil specimens. Banerjee et al (1991), and Lageman and Godschalk (2007) conducted pilot-scale field electrokinetic extraction experiments and obtained very promising results.…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic extraction of lead from kaolinites: II. Experimental investigation

Hsu¹,

Yeung

Menon³

2011

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This is the second paper of two companion papers presenting the results of laboratory bench-scale experimental studies on electrokinetic extraction of lead from two different kaolinites. The theoretical formulation and numerical simulation of the process are presented in the first paper. Two different kaolinites were used in the study: (1) Georgia kaolinite and (2) Milwhite kaolinite. The lead spiked in Georgia kaolinite was highly mobilized and effectively extracted by the technique as the pH in the soil was significantly lowered by the electrokinetic process. Milwhite kaolinite has a much higher acid/base buffer capacity, and the required acidic environment could not be developed. As a result, removal of the lead spiked in Milwhite kaolinite was minimal. Comparison between simulations and experimental results is also presented. Factors affecting the cleanup efficiency of the process and potential enhancement techniques are also discussed.

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Electrokinetic Remediation of Cadmium-Contaminated Clay

Cited by 92 publications

References 15 publications

Electrokinetic extraction of lead from kaolinites: I. Numerical modeling

Electrokinetic extraction of lead from kaolinites: I. Numerical modeling

Pulsed electrokinetic removal of Cd and Zn from fine-grained soil

Electrokinetic extraction of lead from kaolinites: II. Experimental investigation

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