Biochar modification significantly promotes the activity of Co3O4 towards heterogeneous activation of peroxymonosulfate

Extraordinary activation of peroxymonosulfate (PMS) was achieved by Co3O4 fabricated with assistance of rice straw derived biochar (BC-Co3O4). The introduction of biochar significantly improved the specific surface area (from 37.0 to 62.7 m(2)/g). The BC-Co3O4/PMS system showed an excellent performance for the degradation of antibiotics (ofloxacin, OFX in this case). The evolution of radical species was monitored with electron paramagnetic resonance (EPR) technique. Both SO4 center dot- and (OH)-O-center dot contributed to the degradation process and the latter one played a major role. The radicals were mainly generated through heterogeneous mechanism rather than homogeneous process. The effects of experimental conditions (initial pH value, dose of PMS, naturally occurring inorganic anions) on the degradation process were systematically investigated. Eventually, the X-ray photoelectron spectroscopy (XPS) results suggested that the large amounts of Co-OH groups on BC-Co3O4 might be the reason of the extraordinary activity. The findings obtained from this study might be meaningful to enlarge the applications of biochar.