Abstract : Heterogeneous catalysts for the oxidation of toxic compounds are extremely important for many applications including environmental remediation. Here, we assessed the ability of Ti-substituted magnetite, i.e., titanomagnetite (Fe-III ((2-2x)) Fe-II ((1+x)) TixO4) to promote Fenton-like heterogeneous reactions. Two titanomagnetites with x values respectively equal to 0.25 (TM0.25) and 0.75 (TM0.75), as well as unsubstituted magnetite (M, x = 0) were tested for the degradation of phenol under different conditions. Kinetic assessments over 1 h reaction time showed that all the studied systems had the best performance at pH 3. This is the typical, optimal pH value of the Fenton reaction. Moreover, titanomagnetite-based systems were active at low loading and afforded the application of relatively low H2O2 doses. The titanomagnetites had lower ability than magnetite to induce phenol degradation at pH > 3. However, presumably because of the higher Fe(II) content, TM0.75 was less susceptible than M or TM0.25 to the loss in reactivity caused by air exposure. TM0.75 can thus be handled in ambient systems or O-2-containing environments, which may be a key advantage from an application point of view.
