Electrokinetic decontamination of heavy metals in construction materials: contribution of the different parameters to the global efficiency

Castellote, Marta; Botija, Samuel

doi:10.1007/s10800-011-0282-3

Cited by 8 publications

(10 citation statements)

References 10 publications

(20 reference statements)

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“…on soil as well as desorption of these ions using enhancement agents, has been studied. Global efficiency of EK is also very much dependent on zeta potential and conductance as reported by Environ Earth Sci Castellote and Botija (2011). Zeta potential and specific conductivity were also studied to investigate the role of enhancement agents in extraction of Cd ??…”

Section: Introductionmentioning

confidence: 89%

Electrokinetic removal of mixed heavy metals from a contaminated low permeable soil by surfactant and chelants

2014

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This paper presents the experimental findings of electrokinetic (EK) studies conducted to remove cadmium (Cd ?? ) and copper (Cu ?? ) present together as contaminants in clayey soil. Competitive sorption between cadmium and copper has been studied, which provides an insight into selection of Cd ?? and Cu ?? concentrations for maximum contamination of soil in the EK study. To explore the effect of pH on the desorption of both Cd ?? and Cu ?? and to compare the efficacy of different agents in enhancing the removal of these ions during the EK remediation process, the desorption studies have also been conducted using ammonium citrate (1 M), sodium citrate (1 M) and non-ionic surfactant Tween-20 (0.2 % v/v) at pH 2, pH 7, and pH 12. It was found that maximal sorption capacity of the soil for Cd ?? and Cu ?? was 8.34 and 12.1 mg g -1 , respectively. The desorption of both Cd ?? and Cu ?? influenced by pH for all desorbing agents is considered in the study. Overall desorption values for both Cd ?? and Cu ?? have been observed to be higher when ammonium citrate (1 M) was used as desorbing agent in the study. The results indicate the possibility of competition of complexation of Cd ?? and Cu ?? leading to desorption mechanism in the presence of desorbing agents. The EK tests on the Cd ?? and Cu ?? contaminated soil are carried out at a voltage of 35 V (1.0 V/cm) DC for 5 days. Sequential extraction experiments were conducted to determine fractionation of Cd ?? and Cu ?? in the EKtreated soil using deionized water at pH values of 2, 7 and 12. It is observed that current, electroosmotic flow and mobilization of Cd ?? and Cu ?? depend on pH, zeta potential (1) and specific conductance. Removal of these heavy metals was observed to be higher when ammonium citrate was used both for saturation as well as flushing solution during EK process.

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Section: Introductionmentioning

confidence: 89%

Electrokinetic removal of mixed heavy metals from a contaminated low permeable soil by surfactant and chelants

2014

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“…A few of the previous studies 34,36,37,39,41,44,73 discussed the reference conditions of contaminated concretes and considered them to the simulated specimens. Although various contamination methods were proposed, they are not thoroughly validated against the actual sample conditions.…”

Section: Specimen Contamination Methodsmentioning

confidence: 99%

“…Data from the studies of Bostick et al, Lomasney et al, Popov et al, and Castellote et al are excluded from the efficiency evaluation, because they did not report the molar concentration of the targeted contaminants in concrete samples and simply presented the radioactivity of the radioactive contaminants. 34,35,41,73,75 Journal of The Electrochemical Society, 165 (9) E330-E344 (2018) E339 99.7 (Co), 99.6 (Cs) * Varieties of contaminants are noted in parentheses. * * Electric field (V/m) and time (h) used for decontamination.…”

Section: Evaluation Of the Efficiency Of Previous Decontamination Testsmentioning

confidence: 99%

Editors' Choice—Review—Electro-Kinetic Decontamination of Radioactive Concrete Waste from Nuclear Power Plants

Kim

Choi

Shin

2018

J. Electrochem. Soc.

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Electro-kinetic decontamination has been studied for radioactive concrete of nuclear power plants because of its effective removal of contaminants from deep inside concrete. Although many experiments have been conducted, a systematic comparison has been scarcely conducted. By a thorough review, this study reveals how different conditions of electro-kinetic decontamination changes the decontamination ratio and rate of Cs and Co. The tested conditions include cell configurations (i.e., geometry of concrete waste, electrode materials, and volume of solutions) and operating conditions (i.e., types and concentrations of solutions, electric field, and test duration). The careful analysis suggests the important roles of pH in electrolytic solution, electric field, and pre-treatment. We also discuss the chemical conditions under which the decontamination of Cs and Co was optimized in the presence of an applied voltage. In addition, we critically review the conditions of simulated concrete samples in the previous experiments in comparison with actual nuclear plant data.

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“…Concerning removal of metals, most of the treatments incorporate the use of acidic solutions, chelates, or mixed solutions to solubilize them (Reddy and Chinthamreddy 2004;Meers et al 2005;Nystroem et al 2006;Peng et al 2009;Castellote and Botija 2011;Rozas and Castellote 2012;Pedersen et al 2015;Song et al 2016;Yuan et al 2016;Garcia-Blas et al 2020a;Ayyanar and Thatikonda 2021). Other treatments used redox agents (Chuan et al 1996;Reddy and Chinthamreddy 1999;Nystroem et al 2006;Cang et al 2013;Pazos et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Surfactants in electrokinetic remediation of sediments to enhance the removal of metals

2022

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Purpose The study focuses on the use of surfactants as enhancing solutions in electrokinetic remediation trials on sediments, with the hypothesis that they will allow heavy metals to desorb from organic matter, and thus favour their removal to the solution. Materials and methods A total of 15 remediation trials were conducted. As enhancing solutions, four different non-ionic commercial surfactants were used, either alone or in combination with citric acid (CA) or ethylenediaminetetraacetic acid (EDTA) in both compartments. A comparison with distilled water was also performed. 30–40 VDC was applied between activated titanium electrodes. The pH, electroosmotic flow (EOF), mineralogy of the samples (before and after the electrokinetic tests), and the percentage of removal of Cr, Ni, Cu, Zn, As, Cd, Pb, and Hg were determined. Results and discussion Every test showed an increase in current intensity during the first hours, and in certain cases, additional intensity peaks were found during the trial, which were mostly attributed to the establishment of EOF episodes. Depending on the case, EOF was transferred to the anolyte or the catholyte. Reversal of EOF occurred in one case, but was not detected in the others. Cr was primarily removed when CA was used. In the catholite, Ni, Cu, Zn, and Pb were extracted preferentially with EDTA. Surfactant B was more effective at removing Zn and As. Only a few treatments removed Cd with CA and surfactant C extracting the most. Hg was detected in the electrolytes of some experiments, being extracted with surfactant A in the catholyte in all cases, and with surfactant B and surfactant C with EDTA. Cr, Ni, Cu, Zn, Cd, and Pb were preferentially collected in the anolyte. Cu and Zn were found in trace levels in the catholyte. Conclusions Surfactants have been shown to help with metal solubilisation to different degrees depending on the metal. Each metal has a unique optimal species combination in the enhancing electrolyte. The direction of the EOF is determined by the chemical conditions of the system as a whole, not by the type of surfactant. Surfactants in combination with CA and EDTA improve desorption in general, which has been attributed to an increase in charge density passed during the tests rather than a symbiotic enhancement between both types of enhancing solutions.

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Electrokinetic decontamination of heavy metals in construction materials: contribution of the different parameters to the global efficiency

Cited by 8 publications

References 10 publications

Electrokinetic removal of mixed heavy metals from a contaminated low permeable soil by surfactant and chelants

Electrokinetic removal of mixed heavy metals from a contaminated low permeable soil by surfactant and chelants

Editors' Choice—Review—Electro-Kinetic Decontamination of Radioactive Concrete Waste from Nuclear Power Plants

Surfactants in electrokinetic remediation of sediments to enhance the removal of metals

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