Obtaining TiO2:CoFe2O4 nanocatalyst by Pechini method for diuron degradation and mineralization

Abstract

This paper proposes the obtaining of TiO2:CoFe2O4 nanocatalyst aiming to study the efficiency of photocatalytic degradation and mineralization of diuron (DRN). Therefore, the required nanocatalysts were synthesized, and the concentration effect of cobalt spinel ferrite (CoFe2O4) on the properties of TiO2 was investigated. TiO2 and TiO2:CoFe2O4 were synthesized via the Pechini method, while CoFe2O4 was synthesized via the combustion method. The nanocatalysts were characterized by XRD with Rietveld refinement, BET, SEM, granulometric analyses, FTIR, and zeta potential and magnetic measurements. Photocatalytic activity was evaluated by quantification of the final concentration of DRN and total organic carbon. The environmental toxicity was analyzed by using CE50 test. Results showed that all of the nanocatalysts were successfully synthesized. Formation of the major phases, namely, anatase TiO2 and spinel, was observed. Increasing amounts of CoFe2O4 added to TiO2 increased the saturation magnetization of the nanocatalysts from 2.51 emu/g to 19.03 emu/g, which indicates that increasing concentrations of CoFe2O4 could improve the separability of the nanocatalyst from the system after application. The photocatalytic systems achieved 100% DRN degradation, and their mineralization efficiency increased with decreasing CoFe2O4 concentration. The combination of photolysis and photocatalysis improved the efficiency of mineralization. The developed photocatalytic treatment decreased the system toxicity and increased CE50 from 1.5% to 14%.