【作者】 刘宏伟；

【导师】 任何军；

【作者基本信息】 吉林大学 ， 环境工程， 2022， 硕士

【摘要】 利用尖晶石相FeCo₂O₄活化过一硫酸盐（PMS）技术净化废水中有机污染物,具有广阔的应用前景。为了进一步提高FeCo₂O₄活化PMS的效能,本文应用形貌调控和晶格氧空位（V_Os）调整策略制备了富含八面体CO（Ⅱ）的FeCo₂O₄量子点/β-Fe OOH纳米片复合物（CO（Ⅱ）-FCQDs/FNS）,以增强PMS活化来高效降解水中甲硝唑（MNZ）。探究了该催化剂结构与催化性能之间的构效关系,揭示了晶格氧空位衍生的八面体CO（Ⅱ）对PMS活化的增强机制。本文主要研究成果如下:（1）利用形貌调控和晶格氧空位调整策略制备出了具有增强PMS活化性能的新型FeCo₂O₄催化剂:即新型改性FeCo₂O₄量子点催化剂（CO（Ⅱ）-FCQDs/FNS）。系列表征证明CO（Ⅱ）-FCQDs/FNS的形貌是富含八面体CO（Ⅱ）的FeCo₂O₄量子点锚定在具有花状层次结构的β-Fe OOH纳米片上。（2）CO（Ⅱ）-FCQDs/FNS具有较高的PMS利用率（62.90%）。在对MNZ的降解反应中,低浓度的MNZ（C₀[MNZ]<30 mg/L）可以在5 min内完全分解,高浓度MNZ（100 mg/L）的分解率在40分钟时也能达到99.92%,且降解速率常数k_obs是FCQDs/PMS体系的～6.45倍。（3）电子顺磁共振（EPR）和猝灭实验表明PMS/CO（Ⅱ）-FCQDs/FNS体系是纯自由基(硫酸根自由基(SO₄^·-)和羟基自由基（·OH）)的氧化过程。DFT理论计算表明:由晶格氧空位衍生的八面体CO（Ⅱ）:（1）可以改善催化剂晶格内部的电荷转移,即沿着CO（Ⅱ）-O-Fe（II）键;（2）加速金属离子的氧化还原循环;（3）增强HSO₅^-在FeCo₂O₄上的表面吸附,进而增强对PMS的活化能力。更多还原

【Abstract】 The use of spinel FeCo₂O₄-activated peroxymonosulfate（PMS）technology for the purification of organic pollutants in wastewater has promising applications.In order to further improve the effectiveness of FeCo₂O₄-activated PMS,FeCo₂O₄quantum dot/β-Fe OOH nanosheet complexes（CO（Ⅱ）-FCQDs/FNS）enriched with octahedral CO（Ⅱ）were prepared in this paper to boost PMS activation for the efficient degradation of metronidazole（MNZ）in water by applying morphology modulation and lattice oxygen vacancy（V_Os）adjustment strategies.The conformational relationship between the catalyst structure and catalytic performance was investigated,and the mechanism of boosted activation of PMS by lattice oxygen vacancy-derived octahedral CO（Ⅱ）was revealed.The main findings of this paper are as follows.（1）A new FeCo₂O₄catalyst with boosted PMS activation properties was prepared using a morphology modulation and lattice oxygen vacancy adjustment strategy:namely,a new modified FeCo₂O₄quantum dot catalyst（CO（Ⅱ）-FCQDs/FNS）.A series of characterizations demonstrated that the morphology of CO（Ⅱ）-FCQDs/FNS is that of octahedral CO（Ⅱ）-rich FeCo₂O₄quantum dots anchored onβ-Fe OOH nanosheets with a flower-like hierarchical structure.（2）CO（Ⅱ）-FCQDs/FNS had a high PMS utilisation rate（62.90%）.In the degradation reaction for MNZ,low concentrations of MNZ（C₀[MNZ]<30 mg/L）could be completely degraded within 5 min,and the degradation rate for high concentrations of MNZ（100 mg/L）could also reach 99.92%at 40 min,and the degradation rate constant k_obswas～6.45 times higher than that of the FCQDs/PMS system.（3）Electron paramagnetic resonance（EPR）and quenching experiments show that the PMS/CO（Ⅱ）-FCQDs/FNS system was a pure radical-based(sulfate radicals(SO₄^·-)and hydroxyl radicals（·OH）)oxidation process.Density functional theory calculation revealed that the generation of octahedral CO（Ⅱ）derived from V_Os:（i）improved the charge transfer within the catalyst lattice,i.e.along the CO（Ⅱ）-O-Fe（II）bond;（ii）accelerated the redox cycle of metal ions;（iii）strengthened the surface adsorption of HSO₅^-,which in turn boosted the activation of PMS.更多还原