Photocatalyzed N-de-methylation and degradation of crystal violet in titania dispersions under UV irradiation

Chiing Chang Chen, Fu Der Mai, Kung Tung Chen, Chia Wei Wu, Chung Shin Lu

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


TiO2-mediated photocatalytic process has been successfully applied to degrade dye pollutants. In order to obtain a better understanding on the mechanistic details of the TiO2-assisted photodegradation of crystal violet (CV, N,N,N′,N′,N″,N″-hexamethylpararosaniline) dye with UV irradiation, 17 intermediates of the process were separated, identified and characterized by HPLC-ESI-MS techniques in this study. The results indicated that the N-de-methylation degradation of CV dye took place in a stepwise manner to yield mono-, di-, tri-, tetra-, penta-, and hexa-N-de-methylated CV species with N-hydroxymethylated intermediates, which were found for the first time, generated during the processes. Several probable photodegradation pathways were proposed and discussed. The reaction mechanisms of TiO2/UV proposed in this study would be useful for future application of this technology for decoloration of dyes.

Original languageEnglish
Pages (from-to)434-442
Number of pages9
JournalDyes and Pigments
Issue number2
Publication statusPublished - 2007
Externally publishedYes


  • Crystal violet
  • Dye
  • N-De-methylation
  • Photodegradation
  • TiO

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Process Chemistry and Technology


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