CoNx@TiOx纳米棒高效活化PMS降解左氧氟星

CoNx@TiOx degradation of levofloxacin by highly activated PMS with nanorods

  • 摘要: 非均相类芬顿催化氧化是一种很有前途的有机污染物去除方法。本文采用简单乙二醇辅助的方式制备了棒状多孔CoNx@TiOx催化剂。通过XRD、SEM、TEM、HRTEM、XPS对催化剂进行了表征,进一步研究了催化剂活化过氧单硫酸盐(PMS)降解左氧氟沙星(Levo)性能,并详细研究了催化机制。结果表明,CoNx@TiOx在10.5 min内对Levo (20 mg/L)的降解率可达90%左右。进一步探讨了PMS用量、催化剂用量、Levo浓度、水质、污染物及阴离子种类、pH值等环境参数对Levo降解的影响。同时循环实验结果表明,在循环设备运行大约16h内,Levo的降解率仍保持在85%左右,实现了对Levo的持续高效处理。这主要是因为前驱体在高温氮化过程中形成了碳膜,包裹在CoNx@TiOx表面,使催化剂具有优异的稳定性和循环性。电化学测试和自由基淬灭实验表明,空穴和1O2在CoNx@TiOx/PMS体系降解Levo过程中起主要作用。

     

    Abstract: Heterogeneous Fenton catalytic oxidation is a promising method for removing organic pollutants. In this work, a simple ethylene glycol assisted method was used to prepare rod-shaped porous materials CoNx@TiOx catalyzer. The catalyst was characterized and tested by XRD, SEM, TEM, HRTEM, and XPS to further investigate its performance in activating peroxymonosulfate (PMS) to degrade levofloxacin (Levo), and the catalytic mechanism was studied in detail. The results showed that the degradation rate of Levo (20 mg/L) by CoNx@TiOx reached about 90% within 10.5 min. Further exploration was conducted on the effects of environmental parameters such as PMS dosage, catalyst dosage, Levo concentration, water quality, pollutant types, anion types, pH value, etc. on Levo degradation. The results of the cyclic experiment showed that within approximately 16 hours of operation of the cyclic equipment, the degradation rate of Levo remained at around 85% of the catalyst, achieving sustained and efficient treatment of Levo. This is mainly because the precursor formed a carbon film in the high temperature nitriding process, which was wrapped on the surface of CoNx@TiOx, making the catalyst with excellent stability and repeatability. Electrochemical tests and free radical quenching experiments showed that the hole and non-free radical (1O2 and electron transfer) played the main role in the process of Levo degradation in CoNx@TiOx/PMS system.

     

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