Title: Decontamination of a natural multicomponent aqueous liquid waste by titania photocatalysis

Authors: Amjad S. Qazaq, Tedi Hudaya, Ivy A.L. Lee, Andrew Sulidis, Adesoji A. Adesina

Addresses: Reactor Engineering and Technology Group, School of Chemical Sciences and Engineering, The University of New South Wales, NSW 2052, Australia. ' Reactor Engineering and Technology Group, School of Chemical Sciences and Engineering, The University of New South Wales, NSW 2052, Australia. ' Reactor Engineering and Technology Group, School of Chemical Sciences and Engineering, The University of New South Wales, NSW 2052, Australia. ' Reactor Engineering and Technology Group, School of Chemical Sciences and Engineering, The University of New South Wales, NSW 2052, Australia. ' Reactor Engineering and Technology Group, School of Chemical Sciences and Engineering, The University of New South Wales, NSW 2052, Australia

Abstract: The aerobic photocatalytic degradation of municipal dump-site leachate at 300 K has been carried out in a pilot-scale bubble column reactor. The leachate feed is a complex mixture of various organics and nitrogenous compounds. Runs were performed over a 48-hour period at atmospheric pressure. Compositional analysis of aliquots from the reactor revealed simultaneous total organic carbon removal and conversion of uric compounds to ammoniacal species as evidenced by time-on-stream pH increase. A Langmuir-Hinshelwood kinetic model with a unimolecular rate-determining step and a strong adsorption constant (41.6 M−1) adequately described the TOC reduction rate while NH4+ ions production rate attained a maximum around a TOC concentration of 35mM suggesting competitive adsorption between the precursors for the two parallel reactions. Reaction rates exhibited linear dependency on light intensity up to 10−4 Einstein s−1 and thereafter levelled off.

Keywords: titania photocatalysis; leachate; slurry bubble column reactor; municipal solid waste; aqueous liquid waste; waste decontamination; aerobic degradation; kinetic modelling; total organic carbon; TOC removal.

DOI: 10.1504/IJETM.2008.017863

International Journal of Environmental Technology and Management, 2008 Vol.9 No.1, pp.97 - 104

Published online: 20 Apr 2008 *

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