Desenvolvimento de fotocatalisador magnético para degradação do antibiótico ciprofloxacino por fotocatalise heterogênea.

Abstract

This work aimed to synthesize a magnetic photocatalyst, with activity under visible light, capable of degrading the antibiotic ciprofloxacin (cip), by heterogeneous photocatalysis (FH), and to study the operating parameters of

the system. For this, the photocatalysts TiO2, Ag-TiO2, TiO2:CoFe2O4 and Ag- TiO2:CoFe2O4 were synthesized by the Pechini method and CoFe2O4 by the

pilot scale combustion method. Then the structural, morphological, chemical, physical, optical and magnetic characterizations were manifested. The adsorptive behavior was evaluated through the construction of kinetic and isothermal curves. The photocatalytic activity was evaluated under different operational conditions, analyzing the influence of the irradiation source, pH, photocatalyst and CIP concentration and water characteristics. The characteristics appreciated that the synthesis methods were efficient for the production of photocatalysts with desired properties. In adsorption, all photocatalysts, with the exception of CF (CoFe2O4), exhibit significant adsorptive capacity, indicating that the interaction between photocatalyst and CIP in FH will be favored. In FH, LED lamps were the most suitable for activating the studied photocatalysts and Ag-Ti:CF (Ag-TiO2:CoFe2O4) showed superior practicability. The pH of the medium and the concentration of the photocatalyst influenced the degradation of the CIP, with the natural pH (5.8- 6.85) of the solution and the concentration of Ag-Ti:CF equal to 4 mg.mL-1 the conditions that promoted greater efficiency. Ag-Ti:CF was efficient in the photodegradation of CIP in tap water, but pH adjustment was necessary to promote better performance. Salts commonly found in drinking water affected the photodegradation of CIP, with reductions between 6 and 48% being

observed, depending on the salt and pH of the medium. The post- photodegradation CIP solution presented physical-chemical parameters within

the limit recommended by the Brazilian Legislation and the values of significant COD reduction, revealing that Ag-Ti:CF has excellent performance in the photocatalytic treatment of water contaminated with CIP.