Efficient degradation of lomefloxacin by Co-Cu-LDH activating peroxymonosulfate process: Optimization, dynamics, degradation pathway and mechanism

Abstract

In this study, bimetal layered double hydroxides (CoxCuy-LDHs) containing a carbonate interlayer were synthesized using coprecipitation with a variety of Co/Cu mole ratios. Meanwhile, the corresponding layered double oxides (CoxCuy-LDOs) were prepared as controls. In this study, Electrical energy per order was performed to evaluate economic analysis. Correspondingly, we found that CoxCuy-LDHs possessed a significantly better PMS activation capability than the corresponding metal oxide composite (Co3O4/CuO). Compared with other CoxCuy-LDHs, Co2Cu1 LDH possessed the best PMS activation capability for LOM degradation and the lowest electrical energy per order (EE/O) value during the reaction. Additionally, Co2Cu1 LDH presented an excellent stability and worked over a wide pH range. The hydroxide states of Co(III), Co(II), Cu(I) and Cu(II) were all able to activate PMS, indicating that there were many active sites on the surface of Co2Cu1 LDH. The involvement of radicals in this reaction system was determined via scavenger experiments and electron paramagnetic resonance (EPR). Meanwhile, it's worth noting that a mathematical model was developed to quantify the involvement of SO4− and OH. Subsequently, we determined PMS activation mechanism and LOM decomposition pathway for the PMS/Co2Cu1 LDH system.