Activation of persulfate by blue algae biochar supported FeOX particles for tetracycline degradation: Performance and mechanism

Recent research has shown that iron modified biochar has high catalytic performance in peroxydisulfate (PDS) activation; however, the role of iron or complex biochar structure and reaction mechanisms remains unclear. With blue algae as a raw material, recyclable magnetic biochar modified with iron catalyst was produced in this study. Using a combination of electron spin resonance (ESR) and radicals scavenging experiments, it was determined that the TC degradation process included free and non-free radicals. It was accomplished in order to analyse the TC degradation mechanism comprehensively. Superoxide radicals (O2•−) derived from FeOX (zero-valent iron and iron oxide) and PDS played a dominant role by attacking adsorbed TC molecules. The results demonstrated that the modification of FeOX and the structural properties of biochar increased the production of O2•−, thereby accelerating the degradation rate of TC. CC, CO, O-CO, Fe-O functional groups and persistent free radicals (PFRs) promoted the activation of PDS. This non-free radical catalytic process was applicable over a broad pH range and has superior inorganic ion tolerance. This study aids in comprehending the mechanism of the activation and degradation of organic pollutants for PDS by biochar catalysts derived from blue algae. It provides a new method for the future utilization of blue algae resources.