Electro-Fenton and photoelectro-Fenton degradations of the drug beta-blocker propranolol using a Pt anode: identification and evolution of oxidation products.
The beta-blocker propranolol hydrochloride has been degraded by electrochemical advanced oxidation processes like electro-Fenton (EF) and photoelectro-Fenton (PEF) using a single cell with a Pt anode and an air diffusion cathode (ADE) for H(2)O(2) electrogeneration and a combined system containing the above Pt/ADE pair coupled in parallel to a Pt/carbon-felt (CF) cell. Organics are mainly oxidized with hydroxyl radical (OH) formed from Fenton's reaction between added Fe(2+) and electrogenerated H(2)O(2). The PEF treatment in Pt/ADE-Pt/CF system yields almost total mineralization because OH production is enhanced by Fe(2+) regeneration from Fe(3+) reduction at the CF cathode and Fe(III) complexes with generated carboxylic acids are rapidly photodecarboxylated under UVA irradiation. Lower mineralization degree is found for PEF in Pt/ADE cell due to the little influence of UVA light on Fe(2+) regeneration. The homologous EF processes are much less potent as a result of the persistence of Fe(III)-carboxylate complexes. Aromatic intermediates such as 1-naphthol, 1,4-naphthoquinone and phthalic acid and generated carboxylic acids such as pyruvic, glycolic, malonic, maleic, oxamic, oxalic and formic are identified. While chloride ion remains stable, NH(4)(+) and NO(3)(-) ions are released to the medium. A reaction sequence for propranolol hydrochloride mineralization is proposed.
Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
Eloy
E
Isarain-Chávez
Pere Lluís
PL
Cabot
Francesc
F
Centellas
Rosa María
RM
Rodríguez
Conchita
C
Arias
José Antonio
JA
Garrido
Enric
E
Brillas
D000319:Adrenergic beta-Antagonists / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry / Q000379:methods*; D011433:Propranolol / Q000737:chemistry*; D014466:Ultraviolet Rays
D000319:Adrenergic beta-Antagonists; C045076:Fenton's reagent; D011433:Propranolol; D006861:Hydrogen Peroxide; D007501:Iron