title: UV/TiO2 photocatalytic degradation of xanthene dyes.
abstract: 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.
authors: IBB-Institute of Biotechnology and Bioengineering, Centre of Biologic Engineering, Minho University, Braga, Portugal. lucianapereira@deb.uminho.pt
authors: Luciana
authors: L
authors: Pereira
authors: Raquel
authors: R
authors: Pereira
authors: Catarina S
authors: CS
authors: Oliveira
authors: Laura
authors: L
authors: Apostol
authors: Mariana
authors: M
authors: Gavrilescu
authors: Marie-Noëlle
authors: MN
authors: Pons
authors: Orfan
authors: O
authors: Zahraa
authors: Maria Madalena
authors: MM
authors: Alves
mesh_terms: D000327:Adsorption; D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D004396:Coloring Agents / Q000737:chemistry*; D004801:Eosine Yellowish-(YS) / Q000737:chemistry*; D004923:Erythrosine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D055668:Photochemical Processes; D055672:Static Electricity; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; D004923:Erythrosine; D004801:Eosine Yellowish-(YS)