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Diclofenac removal from water by ozone and photolytic TiO 2 catalysed processes
Author(s) -
GarcíaAraya Juan F.,
Beltrán Fernando J.,
Aguinaco Almudena
Publication year - 2010
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2363
Subject(s) - ozone , chemistry , mineralization (soil science) , oxidizing agent , radical , diclofenac , photocatalysis , aqueous solution , decomposition , hydroxyl radical , catalysis , inorganic chemistry , photochemistry , environmental chemistry , organic chemistry , biochemistry , nitrogen
BACKGROUND: The aim of this work was to establish the efficiency of single ozonation at different pH levels (5, 7 and 9) and with different TiO 2 photolytic oxidizing systems (O 2 /UV‐A/TiO 2 , O 3 /UV‐A/TiO 2 or UV‐A/TiO 2 ) for diclofenac removal from water, with especial emphasis on mineralization of the organic matter. RESULTS: In the case of single ozonation processes, results show fast and practically complete elimination of diclofenac, with little differences in removal rates that depend on pH and buffering conditions. In contrast, total organic carbon (TOC) removal rates are slow and mineralization degree reaches 50% at best. As far as photocatalytic processes are concerned, diclofenac is completely removed from the aqueous solutions at high rates. However, unlike single ozonation processes, TOC removal can reach 80%. CONCLUSION: In single ozonation processes, direct ozone reaction is mainly responsible for diclofenac elimination. Once diclofenac has disappeared, its by‐products are removed by reaction with hydroxyl radicals formed in the ozone decomposition and also from the reaction of diclofenac with ozone. In the photocatalytic processes hydroxyl radicals are responsible oxidant species of diclofenac removal as well as by‐products. Copyright © 2010 Society of Chemical Industry