Photocatalytic Detoxification of Antibiotic- and Bacteria-Contaminated Water using Cobalt-Doped Ni–Zn Ferrites Magnetic Separable Nanopowders

Abstract

\n Here, metronidazole (MZ) antibiotic degradation and bactericidal efficacy of Co–Ni0.5Zn0.5Fe2O4 (Co–NZF) with and without photoactivation by UV light is reported as a viable cost-competitive water disinfection solution. Co–NZF has a total pore volume of 0.298 cm3 g−\u20091, a specific surface area of 70.2 m2 g−\u20091 and sufficiently high magnetic properties (80.35 emu g−\u20091). After 360 min of UV–assisted irradiation at pH 3, 10 mg Co–NZF, and 4 mM H2O2, the maximum MZ degradation was reached (92.8%). The adsorption result of 10 mg Co–NZF in the dark for 12 h resulted in 70.2% MZ removal, whereas MZ self-degradation was significantly minimal in a blank trial. In the presence of interfering anions and very high molecular weight tylosin antibiotic, Co–NZF maintained 51.7–75.4% degradation efficiency. The effect of the Co–NZF dosage on the viability of Staphylococcus aureus and Escherichia coli strains showed that 15 mg of the catalyst was sufficient to cause bactericidal activity after 180 min in the presence of UV light, while 25 mg is needed under dark conditions. In addition, when compared to Escherichia coli strains, Co–NZF showed higher inhibition against Staphylococcus aureus in time-kill experiments under dose variation.