Azo dye decolorization by ZVI under circum-neutral pH conditions and the characterization of ZVI corrosion products

Abuzar Khan, Subbaiah Muthu Prabhu, Jaeseon Park, Woojin Lee, Chul Min Chon, Joo Sung Ahn, Giehyeon Lee

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This study examined the effects of initial solution pH (pHi), ZVI dosage, initial Trypan Blue (TB) concentration ([TB]0), and background electrolytes (NaCl and NaNO3) on the rate and extent of dye decolorization. TB azo dye ([TB]0 = 90 μM) was almost completely removed in 1320 min at pHi 4, while only 54% at pHi 10. The effects of Cl and NO3 as a common major anion (10 mM) were contrasting on the efficiency of ZVI decolorization. The former accelerated the decolorization presumably due to impeding surface passivation of secondary Fe (oxyhydr)oxides by forming dissolved Fe–Cl complexes. On the contrary, the latter promoted the formation of secondary oxide layers resulting in the declining the ZVI reactivity. The XRD spectra of reacted ZVI particles suggested that lepidocrocite was initially formed as the ZVI corrosion products, which gradually transformed to magnetite. FT-IR spectroscopy revealed the decolorization processes as the destruction of N[dbnd]N bond in TB dye structure, followed by the formation of free aromatic amine groups ([sbnd]NH2) after 1320 min of reaction with ZVI. The experimental results demonstrated that the novel ZVI treatment system could be a potential and promising alternative technique to remove TB dye by reductive decolorization treatment processes.

Original languageEnglish
Pages (from-to)86-93
Number of pages8
JournalJournal of Industrial and Engineering Chemistry
Publication statusPublished - 2017 Mar 25


All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)

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