Zn-Ferrite and Hematite Dispersed by SBA-15 Silica Grains: Nature, Accessibility and Shape of Supported Oxides Particles: Activity Tests Performed with Visible Light for Advanced Oxidation Process (in Water) on One Antibiotic AMX

Nanoparticles of ZnFe2O4 or hematite of different sizes and shapes are obtained using the two-solvent method (cyclohexane, water) on SBA-15 silica batches. Calcination is performed in air at 700°C with a rate of 2°C by min and quenching for a rapid cooling down until room-temperature. The two inorganic oxides varieties are selected because they are less soluble in water than magnetite and a true heterogeneous reaction can be studied without having a significant parallel homogeneous reaction occurring because of the formation of Fe (II) ions by corrosion (limited Fenton reaction). Their photocatalytic activity is compared under visible light irradiation from a LED lamp, using O2 from air as an oxidizing agent. No H2O2 addition is necessary. We have studied the decomposition of the broad-spectrum antibiotic amoxicillin (AMX) by following the intensity of its signature peak in UV visible spectra and by HPLC chromatography with a C18 column. The photocatalytic activation was demonstrated by measurements performed in the dark also for 225 min. The photocatalytic reaction generates hydroxyl (°OH) and superoxide radicals that yield to a rapid AMX decomposition. An absorption of 7% of AMX occurs within the first 30 minutes of the catalytic test.