OLIVEIRA, P. L.; http://lattes.cnpq.br/3870234890996378; OLIVEIRA, Paloma Lima de.
Résumé:
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.