Comparative studies of various iron-mediated oxidative systems for the photochemical degradation of endosulfan in aqueous solution

Noor S. Shah, Xuexiang He, Javed Ali Khan, Hasan M. Khan, Dominic L. Boccelli, Dionysios D. Dionysiou

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

This study investigated iron-mediated oxidative processes for the photochemical degradation of endosulfan, a chlorinated insecticide and central nervous system disruptor. At UV fluence of 360 mJ/cm2, 52.4% and 32.0% removal of 2.45 μM initial endosulfan was observed by UV/Fe3+ and UV/Fe2+ processes, respectively, at an initial concentration of 17.8 μM iron. The degradation of endosulfan by UV/Fe3+ or UV/Fe2+ was dramatically enhanced by adding peroxide (i.e., H2O2, S2O82- or HSO5-). Among the UV/peroxide/Fe processes, the highest degradation efficiency of 99.0% at UV fluence of 360 mJ/cm2 was observed by UV/HSO5-/Fe2+ with 2.45 μM [endosulfan]0, 17.8 μM [Fe2+]0, and 49.0 μM [HSO5-]0. The observed degradation rate constant of endosulfan was promoted either by increasing [Fe2+]0 and/or [peroxide]0 or by decreasing [endosulfan]0, while the initial degradation rate of endosulfan increased with increasing [Fe2+]0, [peroxide]0, or [endosulfan]0. At UV fluence of 6000 mJ/cm2, 45.0% mineralization as represented by the decrease in total organic carbon content was observed by UV/HSO5-/Fe2+ at 9.80 μM [endosulfan]0, 980 μM [HSO5-]0, and 17.8 μM [Fe2+]0. The major by-product of endosulfan was observed in all cases to be endosulfan ether which was further degraded with an extended reaction time. The results suggest that iron-mediated advanced oxidation processes (AOPs) have a high potential for the removal of endosulfan and its by-product from contaminated water.

Original languageEnglish (US)
Pages (from-to)80-86
Number of pages7
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume306
DOIs
StatePublished - Jun 15 2015
Externally publishedYes

Keywords

  • Advanced oxidation processes (AOPs)
  • Endosulfan
  • Iron
  • Peroxides
  • UV-254 nm
  • Water treatment

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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