Photocatalytic evaluation of the magnetic core@shell system (Co,Mn)Fe 2 O 4 @TiO 2 obtained by the modified Pechini method

Abstract

TiO 2 is a highly active photocatalyst, sometimes obtained with nanometric particle size, which improves its behavior but makes its removal from aqueous media more difficult. To avoid this drawback, this work aims to obtain a photocatalyst easily removable from aqueous media using magnetism. The core@shell system (Co,Mn) Fe 2 O 4 @TiO 2 was prepared by adding commercial (Co,Mn)Fe 2 O 4 nanoparticles to the titanium polymeric resin synthesized by the modified Pechini method. Optimization of photocatalyst properties was achieved by variation of the TiO 2 :ferrite ratio, synthesis temperature and time, followed by their evaluation in photodegradation of an azo dye. The highest efficiency was attained when anatase was the major crystalline phase, whereas TiO 2 :ferrite ratio was limited to 90% to retain the magnetic properties, which enabled its removal from aqueous media using simple magnets. The system (Co,Mn)Fe 2 O 4 @TiO 2 , synthesized with 90% TiO 2 and calcined at 500°C for 8 h, presented a discoloration of 76.3% after 16 h of exposure to UV light.

TiO2 Synthesis by the Pechini’s Method and Application for Diclofenac Photodegradation†

“…In summary, the synthesis may have performed the following functions: (1) sensitization to absorb visible light and (2) the crystalline structure effectively contributes to an effective reduction of band gap energy. The presence of rutile crystalline phase produces these changes in the optical properties (68).…”