Mechanism of action of persulfate activation based on humic acid modified sludge biochar: Enhancement of electron transfer mechanism

Humic acid (HA) was used to modify sludge biochar (SBC) in order to prepare HBC with higher defect structure and abundant oxygenated functional groups. The degradation of TC by HBC was up to 90 % much higher than that of SBC (30 %). HBC possessed a large number of defective structures and oxygenated functional groups, which contributed greatly to the activation of PMS. The co-regulation of highly exposed active sites such as C--O, pyrrole N and pyridine N on HBC2, which played a key role in the activation of PMS. In addition, the results of electrochemical tests indicated that an active intermediate (Persistent free radicals PFRs). Oxygen-centered PFRs were implicated in the movement of electrons through conversion to carbon centers. The conductivity of the process was enhanced by the presence of graphite N. A large number of reactive radicals made sufficient preparations for the production of PFRs. Mutual electron transfer between the oxygen and carbon centers of PFRs was the main mechanism. In addition, the PFRs mechanism and the 1 O 2 mechanism were subjected, which yielded that both degrade TC by electrophilic addition attack and ring-opening reaction, respectively.