title: Sonophotocatalytic degradation of congo red and methyl orange in the presence of TiO2 as a catalyst.
abstract: A comparative study between the photocatalytic and sonophotocatalytic oxidation process of congo red was carried out using titanium dioxide as a catalyst. The effect of a number of parameters, such as the initial concentration of dye, the presence of oxygen and ultrasound, the TiO(2) crystalline structure and the amount of TiO(2), was studied using an inexpensive reactor. In the second part of this document, the oxidation and reduction processes of methyl orange was studied using the same reactor, but by changing the chemical environment in order to drive either the oxidation or the reduction reaction. The results showed, for all the cases studied, a sinergistic effect between sonolysis and photocatalysis when an ultrasonic bath of 80W was used as a source of ultrasound. On the other hand, the electrochemical experiments showed that the current densities for the oxidation process of the azodyes were higher when a conducting glass electrode covered with a thin film of TiO(2) was used as a working electrode instead of a platinum electrode, showing that the TiO(2) electrode is not passivated by the oxidation reaction.
authors.affiliation: Departamento De Química, Facultad De Ciencias, Universidad Nacional De Colombia, Cra 30 # 45-03, Edificio 451, Bogotá, Colombia.
authors.forename: Néstor Javier
authors.initials: NJ
authors.lastname: Bejarano-Pérez
authors.affiliation: Departamento De Química, Facultad De Ciencias, Universidad Nacional De Colombia, Cra 30 # 45-03, Edificio 451, Bogotá, Colombia. Electronic address: mfsuarezh@unal.edu.co.
authors.forename: Marco Fidel
authors.initials: MF
authors.lastname: Suárez-Herrera
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D003224:Congo Red / Q000737:chemistry*; D007220:Industrial Waste; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*; D014465:Ultrasonics; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D001391:Azo Compounds; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D003224:Congo Red; C100258:methyl orange; D014025:Titanium