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Cyclodextrins for remediation of soils contaminated with chlorinated organics

Authors
  • Fenyvesi, É.1
  • Balogh, K.1
  • Oláh, E.1
  • Bátai, B.2
  • Varga, E.1
  • Molnár, M.2
  • Gruiz, K.2
  • 1 Cyclolab Cyclodextrin R&D Laboratory Ltd., Budapest, Hungary , Budapest (Hungary)
  • 2 Budapest University of Technology and Economics, Department of Applied Biotechnology and Food Science, Budapest, Hungary , Budapest (Hungary)
Type
Published Article
Journal
Journal of Inclusion Phenomena and Macrocyclic Chemistry
Publisher
Springer-Verlag
Publication Date
Aug 24, 2010
Volume
70
Issue
3-4
Pages
291–297
Identifiers
DOI: 10.1007/s10847-010-9839-8
Source
Springer Nature
Keywords
License
Yellow

Abstract

The effect of random methylated βCD (RAMEB) on the efficiency of various remediation technologies was studied in lab-scale model-experiments applying soil and groundwater originating from a site contaminated with trichloroethylene (TCE). The solubility of TCE was enhanced to tenfold in 10% solution of RAMEB compared to that in water. This solubilizing effect was utilized for remediation of the TCE contaminated soil using enhanced groundwater extraction and in situ TCE oxidation by ISCO (= in situ chemical oxidation). The effect of CD on TCE extraction from soil was studied using two technologies: ground-water extraction followed by air stripping or UV irradiation. The RAMEB-enhanced ISCO was applied directly to the water-saturated soil without water extraction or separation. The efficiency of air stripping of TCE (removal by bubbling air through the contaminated ground-water obtained by extraction) was decreased in the presence of RAMEB due to the volatility decreasing effect of complexation. The efficiency of the entire technology (extraction and air stripping together) was, however, enhanced as three times more TCE was dissolved, and more than twice as much could be removed when 5% RAMEB solution was applied instead of water. Similar results were obtained by UV irradiation. Although the complexation has a protective effect against degradation caused by irradiation, the efficiency of the technology (extraction and subsequent UV irradiation) is enhanced to approximately threefold, because more than 10 times higher TCE concentration was found in the extract using 20% RAMEB concentration. ISCO is based on Fe-catalyzed oxidation using hydrogen peroxide. The catalytic effect of RAMEB was observed only when it was applied together with Fe(II) salts. Without Fe(II) the effect of complex formation dominated. When hydrogen peroxide and FeSO4 were applied with RAMEB, over five times enhancement in TCE removal was obtained compared to the technology based on the addition of hydrogen peroxide and Fe(II) salts without RAMEB. This effect shows that the solubilizing effect on iron catalyst is at least as much or even more important than the solubilizing effect on TCE. The ternary complex formation with ferrous/ferric ion and TCE seems to be responsible for the enhanced efficacy.

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