Acceleration and quenching of the photolysis of PCB in the presence of surfactant and humic materials

Wei Chu, K. H. Chan, C. Y. Kwan, C. T. Jafvert

Research output: Journal article publicationJournal articleAcademic researchpeer-review

41 Citations (Scopus)

Abstract

The photodecay of a polychlorobiphenyl (PCB) congener, 2,3,4,5- tetrachlorobiphenyl (TeCB), in a surfactant-aided soil-washing process was investigated. The surfactant was found to be a useful hydrogen source in improving the TeCB photodecay via photoreduction process, while the light attenuation effect resulted from the nontarget compounds in the solution, and the impact of humic materials that co-extracted from the soil played important roles in the process of photolvtic destruction of TeCB. A well-defined sediment, EPA-11, was used as the source of humic materials in examining the acceleration and quenching effects in the photolysis process. Experimental results indicated that the low dose of humic materials mainly acted as a supplementary hydrogen source to improve the photodegradation rate, while at a higher dose its amphoteric property of being a photochemical quencher become perceptible gradually, thus retarding the reaction. These effects were inspected and the dominant rate constants were quantified through the examination of possible sub-reactions in the assistant of proposed linear models in this study. The models under three different conditions at zero, low, and high humic levels associated with a light attenuation model were successfully developed to solve the dominant rate constants of the process. The good correlations between the experimental data and the models verify that the proposed reaction mechanisms of rate acceleration (resulting from the hydrogen source characteristics of the surfactant and humic material) and rate retardation (high levels of humic materials) coexist in the process.
Original languageEnglish
Pages (from-to)9211-9216
Number of pages6
JournalEnvironmental Science and Technology
Volume39
Issue number23
DOIs
Publication statusPublished - 1 Dec 2005

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

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