Microwave-induced catalytic degradation is considered amongst the most efficient techniques to remove antibiotic such as chlortetracycline from contaminated water. Described here is a new microwave-induced oxidation catalyst based on carbon nanotubes (CNTs) decorated uniformly with nanoparticles of Fe3O4. The combination of dielectric loss and magnetic loss of the material contributed to its stronger microwave absorption and the ability to produce more "hot spots". These hot spots promoted the oxidation of common antibiotics such as chlortetracycline, tetracycline, and oxytetracycline under microwave irradiation. Experiments with the addition of scavenger showed that hydroxy radicals (•OH) together with superoxide radicals (•O2-) contributed to the antibiotics removal as well. The final degradation products included CO2 and NO3- as confirmed by mass spectroscopy and ion chromatography analyses. The results indicated that the Fe3O4/CNTs was an efficient catalyst for microwave-induced oxidation.
Keywords: catalysts; chlortetracycline; degradation; microwave induced oxidation; nanocomposites.