III International Conference

PP-III-1INFLUENCE OF DISSOLVED OXYGEN ON PHOTOELECTROCATALYTIC AZODYES OXIDATIONAdamadzieva N., Isaev A., Aliev Z.Daghestan State University, Makhachkala, RussiaE-mail: abdul-77@yandex.ruInfluence of dissolved oxygen at different pressure on photoelectrocatalytic azo dyesoxidation is investigated. It is shown, that in the presence of dissolved oxygen the rate ofphotoelectrocatalytic azo dyes oxidation on TiO 2 increases due to formation of active particlesupon oxygen reduction.Synthetic dyes are extensively used for dyeing and printing in textile industries. Over10,000 dyes with an annual production over 7·10 -5 metric tonnes worldwide are commerciallyavailable and about 50 % among them are azo dyes. It is estimated that approximately 15 %of the dyestufs are lost in the industrial effluents during manufacturing and processingoperations. Synthetic dyes, classified by their chromophores, have different and stablechemical structures to meet various coloring requirements. The release of these coloredwastewaters in the ecosystem causes aesthetic pollution, eutrophication and perturbations inaquatic life. Color is usually the first contaminant to be recognized in wastewater. Many azodyes may be decomposed into potential carcinogenic amines under anaerobic conditions inthe environment. Color removal from wastewater is often more important than the removal ofsoluble colorless organic substances, a major fraction of which contributes to the COD andBOD, besides disturbing the ecological system of the receiving waters.In the present work the photoelectrocatalytic oxidation of azo dye direct black 22 at highpressure of oxygen was investigated. For the determination of concentration of dyespectrophotometer was used. Oxidation of azo dye upon photoelectrolysis under pressure ofoxygen occurs not only on the anode TiO 2 , but also on the cathode due to generating activeparticles of ions О 2-, НО2-, radicals НО2·, НО·etc. Increasing of the oxygen pressure leads toan increase of the process efficiency. We have undertaken investigation of the dye-sensitizeddegradation using TiO 2 under artificial source of UV light in a shallow pond slurry reactor atlaboratory scale. Effect of parameters such as UV intensity, pH, initial concentration,oxidants, aperture to volume ratio and catalyst loading on reaction kinetics were studied tooptimize the process.471