Enhanced activation of peroxymonosulfate for ofloxacin rapid degradation and inhibition of metal leaching on LaNi0.6Co0.4O3 stably anchored at ZnO

The citrate sol-gel method was used to synthesize LaNi0.6Co0.4O3 anchored at ZnO (LaNi0.6Co0.4O3/ZnO) for activation of peroxymonosulfate to degrade ofloxacin in simulated wastewater. LaNi0.6Co0.4O3 nanoparticles were uniformly and firmly dispersed on ZnO support during the synthesis process. LaNi0.6Co0.4O3/ZnO had a rapid catalytic rate with an efficiency of 90% in 10 min, which was higher than that of LaNi0.6Co0.4O3 (87.7%). Meanwhile, LaNi0.6Co0.4O3/ZnO significantly inhibited metal ion leaching compared to LaNi0.6Co0.4O3 (Ni leaching: 0.128 mg/L to 0.022 mg/L, Co leaching: 0.083 mg/L to 0.012 mg/L). The composite material maintained great cyclic stability with efficiency of 93% after 5 cycles. Based on electron paramagnetic resonance studies and the quenching experiments, SO4·−、·OH、·O2− and 1O2 were the main reactive oxygen species involved in the reaction. The degradation intermediates of ofloxacin were detected by ICP-MS to propose the possible degradation pathways. This work provides an insight for perovskite catalyst for the activation of PMS to treat pharmaceutical wastewater.