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Photocatalytic ozonation of gallic acid in water
Author(s) -
Beltrán Fernando J,
Gimeno Olga,
Rivas Francisco J,
Carbajo María
Publication year - 2006
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.1605
Subject(s) - photocatalysis , chemistry , gallic acid , oxalic acid , formic acid , ozone , adsorption , aqueous solution , catalysis , nuclear chemistry , inorganic chemistry , organic chemistry , antioxidant
Aqueous solutions of gallic acid have been treated with five different oxidation‐radiation processes: visible and ultraviolet A radiation (VUVA), TiO 2 adsorption, ozonation, VUVA/TiO 2 photocatalysis and VUVA/O 3 /TiO 2 photocatalytic ozonation. With the exception of VUVA radiation and TiO 2 adsorption, ozone and photolytic processes allow for the total removal of gallic acid in a period between 50 and 90 min. The time taken to achieve 100% gallic acid conversion depends on the oxidation process applied, photocatalytic ozonation being the most effective technique. Throughout the process, oxalic and formic acids were identified as byproducts. Some other unidentified compounds probably related to pyruvic, malonic and maleic acids were also detected. The appearance of these compounds can be justified from direct reactions of both hydroxyl radical and ozone in water. Only photocatalytic ozonation leads to total mineralisation of the organic matter in less than 90 min. The photocatalyst used, TiO 2 , showed good activity and stability (no leaching was observed) after five consecutive photocatalytic ozonation runs with the same semiconductor‐catalyst mass. Copyright © 2006 Society of Chemical Industry