title: Removal of emergent contaminants: integration of ozone and photocatalysis.
abstract: A mixture of nine pharmaceuticals has been treated by means of the systems: UV-B(313 nm), O(3), UV-B(313 nm) + TiO(2), O(3) + UV-B(313 nm), and O(3) + UV-B(313 nm)+TiO(2). Simple photolytic or ozonation processes lead to a deficient total organic carbon (TOC) elimination after 120 min of exposure (25 and 30% conversions, respectively). Addition of a photocatalyst such as titanium dioxide significantly enhanced the mineralization degree, a 60% TOC conversion was obtained. A TiO(2) load optimum around 0.25 g L(-1) was observed. No loss in photoactivity was experienced after 2 reuses. Due to ozone photodegradation, the combination of ozone and radiation increased the generation of hydroxyl radicals. As a consequence, TOC removal was increased to a value in the proximity of 85%. The most complex system, O(3) + UV-B(313 nm) + TiO(2), achieved the highest TOC abatement (95%). Use of ozone in photocatalytic processes involves an increase in hydroxyl radical generation.
authors.affiliation: Departamento de Ingeniería Química y Energética, Universidad de Extremadura, Avenida de Elvas S/N, 06071 Badajoz, Spain. fjrivas@unex.es
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Rivas
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Beltrán
authors.forename: Angel
authors.initials: A
authors.lastname: Encinas
mesh_terms: D002384:Catalysis / Q000528:radiation effects; D010126:Ozone / Q000737:chemistry*; D010777:Photochemistry / Q000379:methods*; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D010126:Ozone; D014025:Titanium