Mushroom biochar-based catalysts for high-efficient activated peroxymonosulfate to degrade ketoprofen in the water

In recent years, biochar catalysts have shown great potential in activating persulfate (PS) for organic pollutant degradation in water. However, current challenges persist in biochar-activated PS systems: variations in pyrolysis conditions and precursors compromise long-term operational stability, complex aqueous environments lead to suboptimal degradation efficiency, and activation mechanisms remain scientifically contentious. The characterizations of the mushroom derived biochar (MBC) showed the unique sieve tube structure, rich surface functional groups and large specific surface area (SSA) (632.08 m2/g). The rich surface functional groups and large SSA could facilitate mass transfer and provide rich active sites for activating peroxymonosulfate (PMS). In the MBC-800/PMS system, the degradation efficiency of ketoprofen (KTP) could reach 88.83 %, which higher than other biomass derived biochar and many synthetic activators. The free radical degradation and non-free radical degradation were both involved in this activation reaction, and the sulfate radicals (SO4•-) were the dominant oxidative species for KTP degradation. According to the XPS analysis results, the ketone groups and carboxyl groups were the active sites for activating PMS. In addition, the main intermediates of KTP were analyzed and the pathway of KTP degradation was investigated. This study could provide an effective catalyst for activating PMS and insight into the mechanism of the radicals produced in the biochar/PMS system, which could provide high value for the research of biomass activator to activate PMS.