Oxidative breakdown of acid orange 7 by a manganese oxide containing mine waste: Insight into sorption, kinetics and reaction dynamics

Clarke, Catherine E.; Johnson, Karen L.

Abstract

The reaction rates and orders of azo dye, acid orange 7 (AO 7), oxidation by a Mn oxide containing mine tailings were determined. The reaction is pseudo-first order with respect to the tailings surface area concentration [SA] and pseudo-fractional (0.6) order with respect to AO 7 concentration. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to probe surface sorption and oxidation of AO 7 on a synthetic manganite surface. Sorption is rapid, pH dependent and predominantly outer-sphere. At pH 2.7 a distinct lag phase of 8 min has been observed between dye sorption and the initiation of oxidation. This lag phase suggests that either transfer of the first electron is rate limiting or there is a time consuming re-orientation and inner-sphere sorption step prior to electron transfer.

Citation

Clarke, C. E., & Johnson, K. L. (2010). Oxidative breakdown of acid orange 7 by a manganese oxide containing mine waste: Insight into sorption, kinetics and reaction dynamics. Applied Catalysis B: Environmental, 101(1-2), 13-20. https://doi.org/10.1016/j.apcatb.2010.08.020

• Journal Article Type: Article
• Publication Date: Nov 1, 2010
• Deposit Date: Dec 19, 2011
• Journal: Applied Catalysis B: Environmental
• Print ISSN: 0926-3373
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 101
• Issue: 1-2
• Pages: 13-20
• DOI: https://doi.org/10.1016/j.apcatb.2010.08.020
• Keywords: Orange II, Mn oxide, Mine waste, Redox, Sorption.