FeS2@NCNT阴极电活化过硫酸盐降解诺氟沙星效能的研究

Efficiency of FeS2@NCNT cathodic electroactivation of persulfate for the degradation of norfloxacin

  • 摘要: 基于过硫酸盐活化的高级氧化技术在降解新污染物方面具有独特优势。在利用氮掺杂碳纳米管材料的基础上,将二硫化亚铁包裹在其表面,制备成二硫化亚铁修饰的氮掺杂碳纳米管(FeS2@NCNT),并以诺氟沙星(NOR)为目标污染物,对材料进行表征与电化学性能检测,开展了FeS2@NCNT电活化过一硫酸盐(PMS)降解NOR的机理和性能研究,并进行自由基淬灭实验,探讨共存阴离子对体系性能的影响以及重复性试验。结果表明:1)FeS2@NCNT具有优异的电催化活性和低阻抗特性,表现出良好的电荷存储能力和电子转移能力;2)在FeS2@NCNT/PMS体系中,确定了最佳反应条件为电流密度15 mA/cm2、pH=6.0和PMS浓度3 mmol/L,此条件下60 min内NOR去除率达到93.0%;3)自由基淬灭实验表明单线态氧(1O2)是降解NOR的主要活性物种,超氧自由基(\mathrmO_2^-\cdot )、羟基自由基(·OH)和硫酸根自由基(\mathrmSO_4^ - \cdot)也有一定贡献;4)Cl和\mathrmSO_4^2- 对参与电子转移过程或作为电子供体对体系有促进作用,而\mathrmH_2\mathrmPO_3^-、\mathrmH\mathrmCO_3^- 、\mathrmNO_3^- 和腐殖酸(HA)天然离子对体系降解NOR起到抑制作用,且FeS2@NCNT在多次循环使用后仍能保持良好的催化活性,展示了该复合材料在水处理领域的应用潜力。

     

    Abstract: Advanced oxidation technology based on persulfate (PS) activation has unique advantages in the degradation of emerging pollutants. Based on the use of nitrogen-doped carbon nanotube (NCNT) materials, ferrous disulfide was wrapped on its surface to prepare ferrous disulfide-modified nitrogen-doped carbon nanotubes (FeS2@NCNT). With norfloxacin (NOR) as the target pollutant, the materials were characterized and their electrochemical properties were detected. The mechanism and performance of NOR degradation by FeS2@NCNT-electro-activated peroxymonosulfate (PMS) were studied, and free radical quenching experiments were carried out. The influence of co-existing anions on the system performance and repeatability tests were also investigated. The results showed that: (1) FeS2@NCNT had excellent electrocatalytic activity and low-impedance characteristics, showing good charge storage capacity and electron transfer ability. (2) In the FeS2@NCNT/PMS system, the optimal reaction conditions were determined as a current density of 15 mA/cm2, pH=6.0 and a PMS concentration of 3 mmol/L. Under these conditions, the NOR removal rate reached 93.0% within 60 minutes. (3) Free radical quenching experiments indicated that singlet oxygen (1O2) was the main active species for NOR degradation, and superoxide radicals (\mathrmO_2^-\cdot ), hydroxyl radicals (·OH) and sulfate radicals (\mathrmSO_4^-\cdot ) also contributed to some extent. (4) Cl and \mathrmSO_4^2- participated in the electron transfer process or acted as electron donors, which had a promoting effect on the system, while \mathrmH_2\mathrmPO_3^-、\mathrmH\mathrmCO_3^- 、\mathrmNO_3^- and humic acid (HA) natural ions had an inhibitory effect on the system's degradation of NOR. Moreover, FeS2@NCNT could still maintain good catalytic activity after multiple cycles of use, demonstrating the application potential of this composite material in the field of water treatment.

     

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