Study On Catalytic Activation Of Peroxymonosulfate For Organic Pollutants Degradation By Iron Doped Cobalt Titanate

Heterogenous catalytic generation of sulfate radicals(SO₄^·-)from peroxymonosulfate（PMS）was found to be an effective way for degrading and mineralizing persistent organic pollutants.In particular,cobalt-based catalysts have been studied extensively,but are still confronted with some problems:（1）Co leaching from catalyst trends to cause environmental pollution;（2）The catalytic activity is restricted by the redox cycles of Co（II）/Co（III）;（3）The catalyst powders are difficult to be recycled in heterogeneous reactions,and the catalyst remaining in the water body is likely to cause secondary pollution.To overcome the inherent drawback of cobalt-based catalysts,ilmenite CoTiO₃with a stable crystal structure was selected as the catalyst for activating PMS.Fe-doped CoTiO₃ catalyst was prepared via the co-precipitation method by controlling the feed ratio of the iron source and the cobalt source.Research found that the substitution of partial Co by Fe can modulate the electronic structure and surface chemistry of catalysts,accelerate the Co（II）/Co（III）redox cycle,thereby increasing the reaction rate by 5 times during the process of activating PMS to remove TC.Quenching experiment and electron paramagnetic resonance spectrum found that SO₄^·-,·OH and ¹O₂ were generated during the activation of PMS.Among them,SO₄^·-and ¹O₂ play an important role in the degradation of organic matter.Aiming at the problem that the powder catalyst is difficult to recycle,the Fe-doped CoTiO₃ catalysts were fixed uniformly on the Si O₂ fiber membrane by in-situ growth method to form catalytic separation membrane（FCTSM）with an open catalytic network.In the presence of PMS,organic pollutants（such as nimesulide,methylene blue,etc.）can be effectively degraded into less toxic species after penetrating through the membrane driven by gravity.Besides,98.4%of oil could be rejected from emulsion through the membrane,also indicating good membrane performance.In summary,the Fe-doped CoTiO₃ can efficiently activate PMS to degrade organic pollutants,and it has good application prospects in endowing the membrane with catalytic oxidation performance and improving water treatment efficiency.