Title: Degradation of azo dye in ozonation by noble metal supported mesoporous catalyst

Authors: Santosh P. Ghuge; Anil K. Saroha

Addresses: Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India ' Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India

Abstract: The mesoporous catalyst was prepared by impregnating Ru noble metal on SBA-15 material and its performance was studied in catalytic ozonation reaction for degradation of reactive orange 4 (RO4) azo dye solution. The operational variables such as Ru (%) loadings on SBA-15, initial pH and ozone concentration are optimised in order to get maximum degradation efficiency. The reaction mechanism for catalytic ozonation was analysed by introducing t-butanol as radical scavenger. The colour of RO4 azo dye solution was completely removed after 21 min of catalytic ozonation reaction. The COD removal of 61.1% was achieved at optimised conditions of Ru loading of 0.25% on SBA-15, initial pH 9.0 and ozone concentration of 5 g/m³. The addition of radical scavenger t-butanol in catalytic ozonation reaction indicated that the decolourisation mainly occurred through direct ozone molecular mechanism, whereas degradation of non-colourful groups and intermediates occurred through hydroxyl radical mechanism.

Keywords: catalytic ozonation; Ru/SBA-15; RO4 azo dye; hydroxyl radical.

DOI: 10.1504/IJEWM.2023.130722

International Journal of Environment and Waste Management, 2023 Vol.31 No.3, pp.374 - 386

Received: 13 Apr 2020
Accepted: 12 Jul 2020
Published online: 04 May 2023 *

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