African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6574

Full Length Research Paper

Biphenyl sorption to different soil clay minerals

  Roman Tandlich1,2* and Štefan Baláž1,3
  1Department of Pharmaceutical Sciences, Faculty of Pharmacy, North Dakota State University, Fargo, ND 58105, USA. 2Division of Pharmaceutical Chemistry, Faculty of Pharmacy, Rhodes University, P. O. Box 94, Grahamstown 6140, South Africa. 3Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences-Vermont Campus, Colchester, VT 05446, USA.
Email: [email protected]

  •  Accepted: 22 March 2011
  •  Published: 31 May 2011

Abstract

 

Only limited information is available in the literature on the role of soil mineral surfaces in the sorption of hydrophobic organic pollutants. This knowledge gap is addressed through the assessment of biphenyl sorption to kaolinite, illite and bentonite; using the batch equilibration technique with incubations lasting 6 or 21 days at 28 ± 2°C in the dark [RT1]. Sorption of biphenyl onto kaolinite followed the Freundlich sorption isotherm, whereas linear sorption isotherms were observed on illite and bentonite [RT2]. The biphenyl sorption partition coefficient on kaolinite ranged from 0.1 to 9.1 cm3.g-1 after 6 days and no sorption was observed after 21 days. This could have been caused by a completely reversible sorption or a loss of binding capacity after 21 days [RT3]. The respective values of the biphenyl sorption partition coefficient on illite and bentonite ranged from 20.3 ± 0.3 to 120 ± 8 cm3.g-1.Sorption equilibrium on the internal clay surfaces was reached after 6 days, as indicated by the sorption data for illite and bentonite [RT4]. Access of biphenyl molecules to the internal clay surfaces is a function of the ionic strength of soil solution and the soil organic matter is the dominant site for biphenyl sorption after 6 to 21 days.

 

Key words: Biphenyl, sorption, kaolinite, illite, bentonite.