Photocatalytic oxidation of sulfamethazine.
The photocatalytic degradation of sulfamethazine (SMT), a sulfonamide drug, has been investigated in aqueous heterogeneous solutions containing n-type oxide semiconductors as photocatalysts. The disappearance of the organic molecule follows approximately a pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. It was observed that, with TiO2 P-25 and ZnO as photocatalysts, quantitative degradation of the organic molecule occurs after 4 h. During this time the desulfurization of the substrate is complete, while only 30% of the nitrogen in the organic compound was recovered in the form of nitrate and ammonium ions, indicating that various other nitrogen-containing organic compounds remain in the solution. The addition of H2O2 leads, in the case of TiO2 P-25, to a twofold increase on the reaction rate, while a negative effect has been observed in the presence of ZnO. The initial apparent photonic efficiency (zeta0) of the photooxidation and the mineralization under various experimental conditions have been calculated.
Kaniou
S
S
Veterinary Research Institute of Thessaloniki, 54627 Thessaloniki, Greece.
Pitarakis
K
K
Barlagianni
I
I
Poulios
I
I
D002384:Catalysis; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010777:Photochemistry; D013418:Sulfamethazine / Q000032:analysis* / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000528:radiation effects; D018508:Water Purification / Q000379:methods*; D015034:Zinc Oxide / Q000737:chemistry
D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D013418:Sulfamethazine; D006861:Hydrogen Peroxide; D014025:Titanium; D015034:Zinc Oxide