title: Mineralization of paracetamol in aqueous medium by anodic oxidation with a boron-doped diamond electrode.
abstract: The degradation of 100ml of solutions with paracetamol (N-(4-hydroxyphenyl)acetamide) up to 1 g l(-1) in the pH range 2.0-12.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a graphite cathode, both of 3-cm2 area, by applying a current of 100, 300 and 450 mA between 25 and 45 degrees C. Complete mineralization is always achieved due to the great concentration of hydroxyl radical (*OH) generated at the BDD surface, with release of NH4+ and NO3- ions. The mineralization rate is pH-independent, increases with increasing applied current and temperature, but decreases when drug concentration raises from 315 mg l(-1). Reversed-phase chromatography revealed a similar complex paracetamol decay in acid and alkaline media. Ion-exclusion chromatography allowed the detection of oxalic and oxamic acids as ultimate carboxylic acids. When the same solutions have been comparatively treated with a Pt anode, a quite poor mineralization is found because of the production of much lower *OH concentration. Under these conditions, the degradation rate is enhanced in alkaline medium and polymerization of intermediates is favored in concentrated solutions. Paracetamol can be completely destroyed with Pt and its kinetics follows a pseudo-first-order reaction with a constant rate independent of pH.
authors.affiliation: Laboratori de Ciència i Tecnologia Electroquímica de Materials, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain. brillas@ub.edu
authors.forename: Enric
authors.initials: E
authors.lastname: Brillas
authors.forename: Ignasi
authors.initials: I
authors.lastname: Sirés
authors.forename: Conchita
authors.initials: C
authors.lastname: Arias
authors.forename: Pere Lluís
authors.initials: PL
authors.lastname: Cabot
authors.forename: Francesc
authors.initials: F
authors.lastname: Centellas
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Rodríguez
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Garrido
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D001895:Boron / Q000737:chemistry; D002244:Carbon / Q000737:chemistry / Q000302:isolation & purification; D018130:Diamond / Q000737:chemistry*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D010084:Oxidation-Reduction; D014867:Water; D018508:Water Purification / Q000379:methods*
chemical_list: D008903:Minerals; D014867:Water; D000082:Acetaminophen; D002244:Carbon; D018130:Diamond; D001895:Boron