Amphoteric effect of humic acids in surfactant-aided photolysis of polychlorobiphenyls

Wei Chu, C. Y. Kwan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)


Polychlorobiphenyls (PCBs) are one of the most environmentally problematic organic contaminants present in soils and sediments due to their long-life in direct disposal or spills in soil. It is known that surfactant-aided soil washing followed by a photodechlorination process has the ability to separate PCBs from the soil and decompose them all in one step. However, the influence of humic substances on the removal of PCBs in surfactant-aided ultraviolet systems is of special interest because of the involvement of humic materials in the soil-washing process. A PCB congener, 4,4′-dichlorobiphenyl (DCB) was used as a probe in this study. At low humic acid (HA) concentrations, humic substances promote the photochemical reaction, but a high dose of HA leads to retardation of the DCB decay. A mechanism for the amphoteric effect of HA on the photodecay of DCB is proposed in this study, and two mathematical models are developed to successfully rationalize the amphoteric effect of HA in the photolysis process.
Original languageEnglish
Pages (from-to)716-722
Number of pages7
JournalJournal of Environmental Engineering
Issue number8
Publication statusPublished - 1 Aug 2003


  • Acids
  • PCB
  • Soil pollution
  • Surface-active agents

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry
  • Civil and Structural Engineering


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