Arhoun, B.

Herruzo, F. García

Lahoz, C. Gómez

Merchán, M. C. Rey

Paz-Garcia, Juan Manuel

Rubio, A. García

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 19, 2017Study of the effectiveness of some chelant agents for the remediation of the mercurycontaminated soil from almadenRubio, A. García; Merchán, M. C. Rey; Arhoun, B.; Paz Garcia, Juan Manuel; Lahoz, C. Gómez; Herruzo,F. GarcíaPublished in:Abstracts. 12th Mediterranean Congress of Chemical EngineeringPublication date:2011Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Rubio, A. G., Merchán, M. C. R., Arhoun, B., Paz-Garcia, J. M., Lahoz, C. G., & Herruzo, F. G. (2011). Study ofthe effectiveness of some chelant agents for the remediation of the mercury contaminated soil from almaden. InAbstracts. 12th Mediterranean Congress of Chemical Engineering12th Mediterranean Congress of Chemical Engineering 2.Applied Chemical Engineering 2.2 Environmental Technology   STUDY OF THE EFFECTIVENESS OF SOME CHELANT AGENTS FOR THE REMEDIATION OF THE MERCURY CONTAMINATED SOIL FROM ALMADEN  A. García Rubio, M.C. Rey Merchán, B. Arhoun, J.M. Paz García, C. Gómez Lahoz and F. García Herruzo. Dpto. Ingeniería Química, Universidad de Málaga, Málaga 29071, Spain Tel.: 952 131915, Fax: 952 132000, E-mail: agrubio@uma.es  Scientific Topic: Environmental Technology; Soil Remediation.  In most of the in-situ remediation technologies for heavy metal contaminated soil the use of an extractant agent is usually needed. Therefore, the corresponding feasibility studies of each technological alternative should include the selection of the most suitable agent. This work studies the effectiveness of some chelant agents (thiosulfate, EDTA, iodide and HNO3) for the remediation of the mercury contaminated soil from Almaden mining district (Ciudad Real, Spain).  The kinetic study was performed in batch extraction assays to determine both the adequate extractant agent and its optimal concentration. The extractants tested were NaCl (0.01 M and 0.1 M), EDTA (0.01 M, 0.1 M and 1 M), HNO3 (0.01 M and 0.1 M), KI (5x10-3 M, 0.01 M, 0.1 M and 1 M) and Na2S2O3 (0.01 M, 0.1 M and 1 M).  In addition, the fractionation of the mercury species by the sequential extraction technique based on the method from BCR (Bureau Communautaire de Référence) was also carried out in the initial soil and in the sample corresponding to the equilibrium of each extractant agent. This procedure provides four fractions, which from higher to lower mobility are: weak acid soluble (WAS), reducible, oxidizable and residual.   The results indicate that iodide and thiosulfate and the 1 M solution of EDTA yield the best mercury removal percentages among the 5 chelants tested. The lower EDTA concentration solution and chloride solution extracted at most a 2% of the initial concentration of Hg in the soil. No mercury was extracted by the nitric acid solution. As can be seen in the figure, the equilibrium is reached within the first 24 hours and about 30% of the initial mercury was removed from the soil when iodide and thiosulfate solutions are used.  The distribution of the Hg species in the soil after the iodide extraction is different from that obtained with the thiosulfate extraction. Comparing with the results from the initial soil, the weak acid soluble fraction in the soil after each treatment is much higher than before treatment. This may result in an increase of the environmental risks because this is the most mobile fraction (Subirés-Muñoz et al., 2011). After the evaluation of the best extractant agent for the remediation, we have explored its possible application for soil flushing. When iodide is used as chelating agent in the flushing experiment, a 35% of the mercury can be removed and the speciation results were similar to the ones obtained in the batch experiments. The next flushing experiment will study the removal of mercury with thiosulfate solution as extractant agent. Acknowledgement. This research was funded by Grant PPQ2003-01902  (Spanish Ministry of Education and Science) and Project 148/2004/3 (Ministry for Environment). References J.D. Subirés-Muñoz, A. García-Rubio, C. Vereda-Alonso, C. Gómez-Lahoz, J.M. Rodríguez-Maroto, F. García-Herruzo, J.M. Paz-García. Feasibility study of the use of different extractant agents in the remediation of a mercury contaminated soil from Almaden. Separation and Purification Technology 79 (2011) 151-156. 05101520253035400 6 12 18 24time (h)Hg recovered (%)Iodide 100 mMThiosulfate 100 mM72 168 Figure. Comparison between the kinetic of the extraction of Hg with the iodide solution and with the thiosulfate solution. 

Study of the effectiveness of some chelant agents for the remediation of the mercury contaminated soil from almaden

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 19, 2017Study of the effectiveness of some chelant agents for the remediation of the mercurycontaminated soil from almadenRubio, A. García; Merchán, M. C. Rey; Arhoun, B.; Paz Garcia, Juan Manuel; Lahoz, C. Gómez; Herruzo,F. GarcíaPublication date:2011Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Rubio, A. G., Merchán, M. C. R., Arhoun, B., Paz-Garcia, J. M., Lahoz, C. G., & Herruzo, F. G. (2011). Study ofthe effectiveness of some chelant agents for the remediation of the mercury contaminated soil from almaden.Poster session presented at 12th Mediterranean Congress of Chemical Engineering, Barcelona, Spain.Study of the effectiveness of some chelant agents for the remediation of the mercury contaminated soil from AlmadénA. García Rubio1, M. C. Rey Merchán1, B. Arhoun1, J. M. Paz García2, C. Gómez Lahoz1 and F. García Herruzo11Dpto. de Ingeniería Química, Universidad de Málaga. Málaga, Spain.2Dpt. of Civil Engineering, Technical University of Denmark (DTU), Lyngby, DenmarkFlushing experimentsExperimental setupResultsAcknowledgementThis research was funded by Grant PPQ2003-01902  (Spanish Ministry of Education and Science) and Project 148/2004/3 (Ministry for Environment).In most of the in-situ remediation technologies for heavy metal contaminated soil the use of an extractant agent is usually needed. Therefore, the corresponding feasibility studies of each technological alternative should include the selection of the most suitable agent. This work studies the effectiveness of some chelant agents for the remediation of the mercury contaminated soil from Almaden mining district (Ciudad Real, Spain) based on lixiviation test together with a standard sequential extraction procedure (SEP). The fractionation of the mercury species by BCR (Bureau Communautaire de Référence) was carried out in the initial soil and in the sample corresponding to the equilibrium of each extractant agent. This procedure provides four fractions, which from higher to lower mobility are: weak acid soluble (WAS), reducible, oxidizable and residual.contaminated soil1 g + extraction solution25 mLNaCl (0.01 M, 0.1 M)EDTA (0.01 M, 0.1 M, 1 M)HNO3 (0.01 M, 0.1 M)Na2S2O3 (0.01 M, 0.1 M, 1 M)KI (5·10-3 M, 0.01 M, 0.1 M, 1 M)Shaker22±1ºC∆t: 3 samplespH, [Hg]equilibrium: BCRThe results indicate that iodide, thiosulfate and the 1 M solution of EDTA yield the best mercury removal percentages. However, the lower EDTA concentration solution and chloride solution extracted at most a 2% of the initial concentration of Hg in the soil. No mercury was extracted by the nitric acid solution.The figure on the left shows the distribution of the Hg species in the soil after the batch chelant extraction experiments. Comparing with the results from the initial soil, the weak acid soluble fraction in the soil after each treatment is higher than before treatment. This may result in an increase of the environmental risks because this is the most mobile fraction.Introduction010203040500 6 12 18 24t (h)Hg removal (%)1000 mM100 Mm10 mMModel72 1680102030400 6 12 18 24t (h)Hg removal (%)1000 mM 100 mM10 mM 5 mMModel72 168IODIDE SOLUTION THIOSULFATE SOLUTION020406080100Initial Soil Thiosulphate10 mMKI 100mM EDTA1000mM% HgResidual OxidizableReducible WASBatch chelant extraction experimentsWith Fresh Solutionv=20 cm/h200 mm80 mmperistaltic pumpSamples: pH [Metal]RecycledsolutionmanometersoilWith Recycled Solutionv=2 cm/h80 mmperistaltic pumpSamples: pH [Metal]10-1 M KImanometersoil BCR(each slices)After the evaluation of the best extractant agent for the remediation, we have explored its possible application for soil flushing. When iodide is used as chelating agent in the flushing experiment, a 35% of the mercury can be removed and the speciation results were similar to the ones obtained in the batch experiments. 020040060080010000 5 10Volume of solution (L)[Hg] (mg/L)010203040Hg removal (%)Recycled solution (v=2 cm/h)Fresh solution (v=20 cm/h)5030020406080100% Hg in each BCR fractionResidual Oxidizable Reducible WASRecycled solutionFresh solution1 2 3 4 5 6 7 8 9 10 Initial

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Study of the effectiveness of some chelant agents for the remediation of the mercury contaminated soil from almaden

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