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UV / TiO 2 Photocatalytic Degradation of Xanthene Dyes
Author(s) -
Pereira Luciana,
Pereira Raquel,
Oliveira Catarina S.,
Apostol Laura,
Gavrilescu Mariana,
Pons MarieNoëlle,
Zahraa Orfan,
Madalena Alves Maria
Publication year - 2012
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2012.01208.x
Subject(s) - photocatalysis , xanthene , chemistry , titanium dioxide , biodegradation , degradation (telecommunications) , erythrosine , chemical oxygen demand , respirometry , eosin y , nuclear chemistry , anaerobic exercise , chromatography , photochemistry , chemical engineering , organic chemistry , catalysis , wastewater , environmental engineering , biology , physiology , telecommunications , computer science , engineering
UV /titanium dioxide ( TiO 2 ) degradation of two xanthene dyes, erythrosine B (Ery) and eosin Y (Eos), was studied in a photocatalytic reactor. Photocatalysis was able to degrade 98% of Ery and 73% of Eos and led to 65% of chemical oxygen demand removal. Experiments in buffered solutions at different initial pH values reveal the pH dependence of the process, with better results obtained under acidic conditions due to the electrostatic attraction caused by the opposite charges of TiO 2 (positive) and of anionic dyes (negative). Batch activity tests under methanogenic conditions showed the high toxicity exerted by the dyes even at low concentrations (~85% with initial concentration of 0.3 mmol L −1 ), but the end products of photocatalytic treatment were much less toxic toward methanogenic bacteria, as detoxification of 85 ± 5% for Eos and 64 ± 7% for Ery were obtained. In contrast, the dyes had no inhibitory effect on the biogenic‐carbon biodegradation activity of aerobic biomass, obtained by respirometry. The results demonstrate that photocatalysis combining UV / TiO 2 as a pretreatment followed by an anaerobic biological process may be promising for the treatment of wastewaters produced by many industries.