Photocatalytic evaluation of the magnetic core@shell system (Co,Mn)Fe2O4@TiO2 obtained by the modified Pechini method

A.M Neris,W.H Schreiner,C Salvador,U.C Silva,C Chesman,E Longo,I.M.G Santos

doi:10.1016/j.mseb.2017.12.029

Abstract

TiO2 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)Fe2O4@TiO2 was prepared by adding commercial (Co,Mn)Fe2O4 nanoparticles to the titanium polymeric resin synthesized by the modified Pechini method. Optimization of photocatalyst properties was achieved by variation of the TiO2: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 TiO2: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)Fe2O4@TiO2, synthesized with 90% TiO2 and calcined at 500 °C for 8 h, presented a discoloration of 76.3% after 16 h of exposure to UV light.

Highlights

Titanium dioxide is a semiconductor material widely used in heterogeneous photocatalysis due to its high photochemical reactivity, stability in aqueous systems and low environmental toxicity [1,2,3,4]
Xin et al reports the synthesis of the Fe3O4@TiO2 core@shell system by the solvothermal method, with good magnetic properties at room temperature and good photocatalytic activity for degradation of Rhodamine B dye (RhB) in solution [24]
The reuse of a core-shell photocatalyst was determined by Zheng et al [26], who evaluated the photodegradation of methylene blue by Fe3O4@TiO2 obtained by the liquid phase deposition (LPD) method, using visible irradiation with a high efficiency

Summary

Introduction

Titanium dioxide is a semiconductor material widely used in heterogeneous photocatalysis due to its high photochemical reactivity, stability in aqueous systems and low environmental toxicity [1,2,3,4]. Xin et al reports the synthesis of the Fe3O4@TiO2 core@shell system by the solvothermal method, with good magnetic properties at room temperature and good photocatalytic activity for degradation of Rhodamine B dye (RhB) in solution [24]. The reuse of a core-shell photocatalyst was determined by Zheng et al [26], who evaluated the photodegradation of methylene blue by Fe3O4@TiO2 obtained by the liquid phase deposition (LPD) method, using visible irradiation with a high efficiency. Habila et al [20] reported the high photocatalytic efficiency of the core@shell system containing a magnetic core and multiple layers, forming the Fe3O4@SiO2@TiO2 system for decomposition of tartrazine and the yellow twilight in aqueous solution under UV radiation. In addition to other core@shell systems with magnetic cores, the use of structures containing Ag [30,31] or Cu [32] stands out for photocatalytic applications

Objectives

Methods

Findings

Conclusion