Enhanced Photocatalytic Degradation of Diclofenac by Sn0.15Mn0.85Fe2O4 Catalyst under Solar Light

Abstract In this present study, tin (Sn) doped MnFe2O4 (Sn0.15Mn0.85Fe2O4) nanocomposites were synthesized using a microwave combustion method by employing Alocasia odutra plant extract as a natural fuel. Sn is well incorporated with spinel ferrite (MnFe2O4) which is confirmed by XRD analysis. FE-SEM analysis indicates that the synthesized sample having a rod-like structure in nature. The emerging pharmaceutical contaminant, namely, diclofenac (2-(2-(2,6-dichlorophenylamino)phenyl) acetic acid) (DCF), the non-steroidal anti-inflammatory drug was utilized as a model pollutant to evaluate the catalytic efficiency of the Sn0.15Mn0.85Fe2O4 (SMF) under solar irradiation. SMF shows higher catalytic activity than pristine MnFe2O4 due to a reduction in the bandgap energy from 1.78 eV to 1.54 eV as a result of Sn doping into MnFe2O4. The degradation efficiency of DCF using the SMF catalyst was found to be 99% in a shorter interval (50 min) with 71% mineralization. Radical trapping experiments indicate that the photo-generated holes and hydroxyl radicals actively participate in the degradation process of DCF using the SMF catalyst. The optimum pH for the removal of DCF using the SMF catalyst was found to be 4 with the catalyst dosage of 0.8 g/L. The recycling experiment shows that the SMF catalyst has high stability up to five cycles and low iron leaching ability under optimum conditions. Sn0.15Mn0.85Fe2O4 catalyst can be recovered using an external magnet from the reaction mixture and it is recycled. It was concluded that the synthesized catalyst can be used as a tertiary treatment option for the removal of emerging pharmaceutical pollutants.