Facile synthesis of highly efficient and cost-effective photo-Fenton catalyst by ball milling commercial TiO2 and natural magnetite

Heterogeneous Fenton reaction is a usable technique to remove organic contaminants in water, while developing highly efficient and cost-effective catalysts with simple preparation method is critical for its practical application. In this work, novel TiO 2 /Mag composites were prepared from commercial TiO 2 and natural magnetite (Mag) via a facile ball milling process. We expect the obtained composites to be efficient photo-Fenton catalysts, as photo-generated electrons from TiO 2 can be transferred to Mag to accelerate the reduction of Fe(III) to Fe(II), promoting the decomposition of H 2 O 2 and production of ·OH. Structural characterization results exhibited ball milling could not change mineral phases of both TiO 2 and Mag. TiO 2 /Mag composites remained good magnetic saturation and could be rapidly separated from reaction medium. In degrading cefotaxime, TiO 2 /Mag composites showed high photo-Fenton catalytic activities, with the degradation rate by 10%TiO 2 /Mag at near neutral pH of 5.6 being about 11.6 and 8.2 times higher than that of natural and ball-milled Mag, respectively. Moreover, even at low H 2 O 2 concentration of 1 mmol/L, 10%TiO 2 /Mag remained relatively high photo-Fenton catalytic activity when compared to natural and ball-milled Mag. The better production of ·OH in the photo-Fenton system catalyzed by 10%TiO 2 /Mag (0.244 mmol/L) than that by natural and ball-milled Mag (0.049 and 0.064 mmol/L) also illustrated efficient utilization of H 2 O 2 by 10%TiO 2 /Mag. Above results well support our hypothesis that photo-generated electrons from TiO 2 were transferred to Mag, which then benefited the Fenton reactivity of Mag and degradation of cefotaxime. In all, TiO 2 /Mag composites prepared by ball milling have promising practical application in water treatment, thanks to their merits such as high photo-Fenton catalytic activity, facile preparation, cost-effective, easy magnetic separation, good stability, suitable for near neutral pH, and efficient utilization of H 2 O 2 .