Nonionic organic solute sorption onto two organobentonites as a function of organic-carbon content

Shannon L. Bartelt-Hunt, Susan E. Burns, James A. Smith

Research output: Contribution to journalArticle

120 Scopus citations

Abstract

Sorption of three nonionic organic solutes (benzene, trichloroethene, and 1,2-dichlorobenzene) to hexadecyltrimethylammonium bentonite (HDTMA bentonite) and benzyltriethylammonium bentonite (BTEA bentonite) was measured as a function of total organic-carbon content at quaternary ammonium cation loadings ranging from 30 to 100% of the clay's cation-exchange capacity. Sorption of all three solutes to HDTMA bentonite was linear and sorption of all three solutes by the HDTMA bentonite increased as the organic-carbon content of the clay increased. 1,2-Dichlorobenzene sorbed most strongly to HDTMA bentonite, followed by benzene and TCE. The stronger sorption of benzene to HDTMA bentonite compared to TCE was unexpected based on a partition mechanism of sorption and consideration of solute solubility. Log Koc values for all three solutes increased with organic-carbon content. This suggests that the increased organic-carbon content alone may not explain the observed increase in sorption capacity. Sorption of the three solutes to BTEA bentonite was nonlinear and solute sorption increased with decreasing organic-carbon content, with a peak in the magnitude of solute sorption occurring at an organic-carbon content corresponding to 50% of CEC. Below 50% of CEC, sorption of all three solutes to BTEA bentonite decreased with decreasing organic-carbon content. Surface area measurements indicate that the surface area of both organobentonites generally decreased with increasing organic-carbon content. Since nonionic organic solute sorption to BTEA bentonite occurs by adsorption, the reduced sorption is likely caused by the reduction in surface area corresponding to increased organic-cation loading.

Original languageEnglish (US)
Pages (from-to)251-258
Number of pages8
JournalJournal of Colloid and Interface Science
Volume266
Issue number2
DOIs
StatePublished - Oct 15 2003

Keywords

  • 1,2-Dichlorobenzene
  • Adsorption
  • Bentonite
  • Benzene
  • Organic cations
  • Organoclay
  • Partitioning
  • Trichloroethylene

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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