Ultrasound-assisted heterogeneous activation of persulfate by nano zero-valent iron (nZVI) for the PAC in-situ regeneration

In this work, a new ultrasound-assisted heterogeneous activation of persulfate by nano zero-valent iron (US-nZVI/PS) technique was employed to regenerate powder activated carbon (PAC) that had been saturated with chloramphenicol (CAP). US-nZVI/PS process can successfully regenerate the CAP-saturated PAC. Response surface methodology was effectively performed and under the specific optimum regeneration conditions the actual experimental regeneration efficiency of PAC reached 93.96%. As evidenced by the results of EPR and quenching experiments, both SO4•− and •OH were identified as the main reactive species responsible for the regeneration process. The regeneration process considerably promoted the generation of oxygen-derived surface functional groups.