Heterogeneous catalytic ozonation of phenacetin in water using magnetic spinel ferrite as catalyst: Comparison of surface property and efficiency

In this study, a systematic investigation on the degradation of phenacetin (PNT) by magnetic spinel ferrite (including MnFe2O4and NiFe2O4) via catalytic ozonation was carried out. The structural and surface property of the catalyst, the performance and mineralization during PNT degradation, and •OH/H2O2identification were studied. The precursors of the catalyst, i.e. MnFe2(OH)8and NiFe2(OH)8, showed certain magnetic properties and a superior catalytic activity for ozonation enhancement than spinel ferrites. Spinel ferrites containing manganese initiate an ozone mass transfer into the solution, where the critical intermediate (H2O2) is generated. The manganese ferrite spinel triggers H2O2decomposition in the presence of ozone and generates •OH for the mineralization of PNT and its intermediates. Spinel ferrites involved nickel catalyzed ozone decomposition and generate H2O2and •OH. All catalysts showed a weak heavy metal leaching, which suggests that the heterogeneous reaction dominates the catalytic reaction and the resultant effluent is safe for the aqueous environment. The magnetic variation of catalysts involving nickel is insignificant, suggesting that the catalyst can be reused many times. The fate of the intermediates on spinel oxides surface influenced for the catalytic ozonation process differently.