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Role of oxygen at the TiO 2 interface during photodegradation of biologically difficult‐to‐degrade anthraquinone‐sulfonate dyes
Author(s) -
Kiwi John
Publication year - 1994
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620131004
Subject(s) - photodegradation , photocatalysis , chemistry , decomposition , degradation (telecommunications) , adsorption , oxygen , anthraquinone , photochemistry , inorganic chemistry , nuclear chemistry , catalysis , organic chemistry , telecommunications , computer science
Heterogeneous photocatalysis via TiO 2 suspensions is effective in anthraquinone 2 sulfonic acid sodium salt (ASS) degradation The presence of oxygen promotes the observed semiconductor powder oxidation of the substrate Degradation of ASS in aerated dispersions of TiO 2 needed about 24 h at 60°C Added H 2 O 2 enhances the degradation rate considerably As the pH increases, the H 2 O 2 produced also increases Also, peroxide production was observed as the concentration of TiO 2 is increased owing to the availability of more surface states for the reaction The Langmuir adsorption isotherm of ASS on TiO 2 Degussa P‐25 shows that ASS adsorbs readily on the TiO 2 particles The observed rate for H 2 O 2 production decreased as the concentration of isopropanol (hole scavenger) is increased, suggesting an oxidative pathway as the main reaction responsible for H 2 O 2 photoproduction The degradation of ASS is a result of indirect action due to light mainly absorbed by TiO 2 The experiments described here demonstrate the feasibility of dyestuff decomposition via semiconductor powders