Absorption and adsorption of hydrophobic organic contaminants to diesel and hexane soot

Thanh H. Nguyen, William P. Ball

Research output: Contribution to journalArticlepeer-review

Abstract

Soot particles vary in pore structure, surface properties, and content of authigenic (native) extractable organic chemicals. To better understand the effects of these properties on sorption, aqueous sorption isotherms for 14C-labeled phenanthrene and 1,2,4-trichlorobenzene were obtained for four soots of varying properties: two diesel reference soots, a hexane soot, and an ozonated hexane soot. Substantial isotherm nonlinearity was observed. In comparison to diesel soot SRM 2975, diesel soot SRM 1650b had a much higher content of extractable authigenic organic chemicals, showed less sorption of 14C-labeled sorbate at low relative concentrations (C e/SW), and showed higher sorption at high C e/SW. In comparison to normal hexane soot, the ozonated hexane soot had a higher surface O/C ratio and showed substantially less sorption at all concentrations studied. The sorption differences were attributed to the noted differences in properties, and results were interpreted through a dual-mode sorption model that included the possibility of both surface adsorption (modeled using a Polanyi-based approach) and simple phase partitioning (linear absorption). Generally, such modeling indicated that overall uptake at low concentrations in all four soots was dominated by surface adsorption but that sorption at higher sorbate concentrations in SRM 1650b was heavily influenced by linear absorption within the natively bound organic phase.

Original languageEnglish (US)
Pages (from-to)2958-2964
Number of pages7
JournalEnvironmental Science and Technology
Volume40
Issue number9
DOIs
StatePublished - May 1 2006
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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