Magnetic CoFe2O4 ferrite for peroxymonosulfate activation for disinfection of wastewater

Resumen

The total inactivation processes of two pathogenic bacteria, Escherichia coli and Enterococcus sp., by peroxymonosulfate (PMS) activation with CoFe2O4 nanoparticles was studied in real and simulated wastewater matrices. The catalyst was prepared by solvothermal method and characterized by means of powder X-ray diffraction and Transmission Electron Microscopy. It shows an excellent heterogeneous catalytic activity for PMS activation, easy separation, acceptable reusability and negligible leaching. A systematic study for the determination of optima catalyst and PMS dosages (0.05 g/L CoFe2O4 and 0.2 mM PMS) were investigated under UV-A radiation and darkness for an initial bacteria concentration of 106 CFU/mL. Scavenging experiments using methanol and TBA were performed to confirm that both, sulfate (SO4•-) and hydroxyl radicals (HO•), are involved in the inactivation process. A plausible mechanism reaction was proposed for UV-A and darkness and a Double Weibull mathematical model seems to fully describe the kinetic inactivation of both bacteria. The use of low catalyst and PMS concentrations concomitantly to the high efficiency showed for the total inactivation of wild bacteria in darkness makes this process suitable to be the last stage in a full wastewater treatment plant.