Rapid removal of high-concentration Rhodamine B by peroxymonosulfate activated with Co 3 O 4 -Fe 3 O 4 composite loaded on rice straw biochar

In this study, rice straw biochar modified with Co 3 O 4 -Fe 3 O 4 (RSBC@Co 3 O 4 -Fe 3 O 4 ) was successfully prepared via calcinating oxalate coprecipitation precursor and employed as a catalyst to activate peroxymonosulfate (PMS) for the treatment of Rhodamine B (RhB)-simulated wastewater. The results indicated that RSBC@Co 3 O 4 -Fe 3 O 4 exhibited high catalytic performance due to the synergy between Co 3 O 4 and Fe 3 O 4 doping into RSBC. Approximately 98% of RhB (180 mg/L) was degraded in the RSBC@Co 3 O 4 -Fe 3 O 4 /PMS system at initial pH 7 within 15 min. The degradation efficiency of RhB maintained over 90% after the fourth cycle, illustrating that RSBC@Co 3 O 4 -Fe 3 O 4 displayed excellent stability and reusability. The primary reactive oxygen species (ROS) answerable for the degradation of RhB were 1 O 2 , •OH, and SO 4 •− . Moreover, the intermediates involved in the degradation of RhB were identified and the possible degradation pathways were deduced. This work can provide a new approach to explore Co-based and BC-based catalysts for the degradation of organic pollutants.