A core-heteroshell structural magnetic composite of ZIF-67/Vanadium-titanium magnetite (VTM) was successfully synthesized through a feasible solvothermal method and efficiently used in activation of peroxymonosulfate (PMS) for the treatment of levofloxacin (LVF) in an aqueous solution. The catalytic activity of the ZIF-67/VTM composite in LVF degradation was thoroughly evaluated, demonstrating the LVF removal rate could reach up to 93.3% within 60 min at ZIF-67/VTM composite dosage of 100 mg/L, PMS concertation of 75 mg/L, and the natural pH of 6.4. It is quite interesting that the carbon organic skeleton (in the ZIF-67 shell) have accelerated the internal electron transformation rate of the ZIF-67/VTM composite, thus efficiently promoting the O–O band (in PMS) breakage and the redox cycle of cobalt, further favoring the free radicals generation. The quenching experiments and EPR analysis results demonstrated that ·SO 4 − would play a crucial role in the LVF degradation process. Surprisingly, we have found that the introduction of Cl − (at some certain dosage) would not always decrease the LVF degradation ratio, for a new reactive oxygen species (singlet oxygen) was emerged in this system. What's more, the ZIF-67 (as the wrapping structure) could stabilize the VTM (the inner structure) in changing reaction conditions, prompting a good adaptability at a wider pH range (3–10) for inhibiting the leaching of various metal ions into the aqueous solution. This novel ZIF-67/VTM composite could provide new ideas and routes for the removal of emerging pollutants from an aqueous solution.
Jingwei Yan,Lin Gong,Senyou Chai,Cong Guo,Wei Zhang,Hongyou Wan
The dual effect of chloride anions (Cl − ) on sulfate radical-advanced oxidation process (SR-AOP) systems has recently garnered increasing attention, particularly the inhibitory effects of Cl − on the degradation of organic pollutants. However, few studies have characterized the promoting effect of Cl − on SR-AOPs. Our study investigated the effect of Cl − on the degradation of levofloxacin (LVF) in peroxymonosulfate (PMS) with ZIF-67/VTM (Z-VTM) as an activator. With the addition of Cl − , singlet oxygen ( 1 O 2 ) was the dominant driver of LVF degradation in the Cl − /Z-VTM/PMS system, which differed from the dominant role of HOCl (generated from Cl − ) in the degradation of organic pollutants in previous studies. To the best of our knowledge, our study is the first to describe the conversion of HOCl to 1 O 2 in a Cl − /Z-VTM/PMS system. 1 O 2 was effectively generated in Cl − containing water at a 3.0–9.0 pH range. This work provides novel insights into the formation of ROS from HOCl during the degradation of organic pollutants in SR-AOPs, which is of great significance for the removal of organic pollutants in wastewater with high salt concentrations.
危险品化学品经营许可证（带存储）