Degradation of 1-naphthylamine by a UV enhanced Fe2+/peroxymonosulfate system: A novel pH-dependent activation pathway

Jianghui Liu, Hiu Lam So, Wei Chu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


This study demonstrated an Advanced Oxidation Process (AOPs) by the activation of Peroxymonosulfate (PMS) through Fe2+ and UV for the degradation of 1-naphthylamine (1-NA). A series of processes including Fe2+/PMS, Fe2+/UV, PMS/UV, Fe2+/PMS/UV and direct photolysis by UV-A, UV-B, UV-C were examined. Comparatively, the Fe2+/PMS/UV process was highlighted to have the most remarkable degradation efficiency with 100% 1-NA removal within 20 min. The total organic carbon (TOC) removal can achieve 83.5% (mineralization rate = 0.08 g TOC/min) by 1.5 h under higher Fe2+/PMS dosage. The superior performance was ascribed to the activation of PMS into exclusive sulfate radicals (SO4•–) and hydroxyl radicals (OH). The optimal Fe2+/PMS ratio, pH level, and UV wavelength were determined to be [Fe2+: PMS]0 = 1: 2, wavelength = 254 nm, pH = 2.98. This process was observed to be a pH dependent process. A rise of degradation efficiency was observed once the pH was adjusted to above the pKa of 1-NA and was rationalized by the NaOH activation of PMS. Pigments were observed in different conditions and were justified by spectrophotometric analysis. By proposing GC/MS and LC/MS analysis, lawsone and juglone were identified as the major product. The oxidation reaction initiated by SO4•– and OH has contributed a dominant role in the process, nevertheless, the redox cycle introduced by Fe2+/Fe3+ can contribute the reduction of diol to quinone intermediates, which can accelerate the degradation ultimately.

Original languageEnglish
Article number136299
JournalChemical Engineering Journal
Publication statusPublished - 1 Sept 2022


  • 1-Naphthylamine
  • AOPs
  • Fe/PMS/UV
  • Hydroxyl radical
  • Sulfate radical

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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