Feijoo Conde, Jorge

Matyscak, Ondrej

Ottosen, Lisbeth M.

Rivas, T.

Online Research Database In Technology

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ComparisonFeijoo Conde, Jorge; Matyscak, Ondrej; Ottosen, Lisbeth M.; Rivas, T.Published in:Proceedings of the 13th Symposium on Electrokinetic RemediationPublication date:2014Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Feijoo Conde, J., Matyscak, O., Ottosen, L. M., & Rivas, T. (2014). Desalination of granite and sandstones byelectrokinetic techniques. Comparison. In Proceedings of the 13th Symposium on Electrokinetic Remediation(pp. 75-76)EREM2014 13th Symposium on Electrokinetic Remediation Malaga, Spain  96 Nº REF.: O464 Desalination of granite and sandstones by electrokinetic techniques. Comparison Jorge Feijoo Condea*,  Ondrej  Matyščákb, Lisbeth M. Ottosenc, T. Rivas aDept. of Natural resources and environmental. University of Vigo Campus Lagoas, 36310 Vigo-Spain bDepartment of Civil Engineering, Brno University of Technology, 602 00 Brno, Czech Republic cDepartment of Civil Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark * jfeijoo@uvigo.es Soluble salts are considered as a main reason for damage of porous building materials such as rocks, bricks, granites which are used in the building constructions of the architectural and archaeological heritage. Soluble salts are also responsible for various forms of deterioration such as sand disaggregation and superficial detachments [1-3]. These problems can be solved by conservation technologies which are aimed at decreasing the salt concentration in the rocks (desalination). The present study aims to investigate the efficiency of electrokinetic techniques for desalination of two different kinds of rocks such as granite and sandstone in which this technique had already been shown to be effective [4, 5]. These rocks were contaminated with NaCl solution and the thickness of the samples used in the tests was 6 cm. This study compares the percentage removal of salts at different depths (efficacy) and the time needed to get this percentage removal (effectiveness) achieved in both stones. From the results obtained, it was possible to find those inherent factors to each stone which could have an influence on the efficacy of the treatment. As the results, this technique reduced the salt concentration in the granite almost to 100 %, however, in the sandstone samples the decreases were not so high mainly at the intermediate levels (Figure 1) where slight enrichments were observed. The obtained results indicate that although the used technique is efficient for the salt removal regardless of porosimetric distribution of the rock, the better interconnection between the pores (the granite used in this research had a better interconnection) favored that the desalination process in the material happened faster.  EREM2014 13th Symposium on Electrokinetic Remediation Malaga, Spain  97  Figure 1.: a) chloride content (%Cl- g/g referred to the dry weight of the stone) by depth inside the stones (granite; sandstone) before and after desalination test (seven application); b) efficacy (%Cl-) achieved in each rock References [1] Charola, A.E. Salts in the deterioration of porous materials: an overview. Journal of America Institute of Conservation 39 (2000) 327-343.  [2] Doehne, E. Salt weathering: a selective review. Segesmund S., Weiss T. and Vollbrecht A. Natural stone weathering phenomena, conservation strategies and case studies. Geological Society. London. Special publications, 205, 51-64 (2002). [3] Silva, B.; Rivas, T.; Prieto, B. (2003).- “Soluble   salts   in   granitic   monuments:  origin and decay effects. Applied Study of Cultural Heritage and Clays.J.L. Pérez (Ed.), pp 113-130. [4] Feijoo. J.; Nóvoa. X.R.; Rivas. T.; Mosquera. M.J.; Taboada. J.; Montojo. C.; Carrera. F. (2012).- “Granite   desalination   using   electromigration.   Influence   of  type  of  granite  and  saline  contaminant”.  Journal  of  Cultural  Heritage. [5] Ottosen, L.M.; Christensen, I. (2012) Electrokinetic desalination of sandstones for NaCl removal – Test of different clay poultices at the electrodes. Electrochimica Acta  Acknowledgements J. Feijoo research was funded by a FPU-predoctoral grant by the Ministerio de Educación of Spain.  

Desalination of granite and sandstones by electrokinetic techniques. Comparison

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Desalination of granite and sandstones by electrokinetic techniques. Comparison

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