【作者】 刘芳；

【导师】 杨朝晖； 孙赛武；

【作者基本信息】 湖南大学 ， 环境工程（专业学位）， 2021， 硕士

【摘要】 四环素（TC）由于其抗菌效果好,因此被广泛应用于医疗以及畜牧养殖行业。然而,在近些年以来,由于含TC废水的不合理处置,导致对环境的污染和对人类的危害更加严重。传统的水处理方法难以将TC完全去除,因此需要开发高效能的方法对TC废水进行处理。目前,基于硫酸根自由基的高级氧化技术因其良好的催化效果得到广泛关注,过一硫酸盐（PMS）的活化可以产生SO₄^·-。Co²⁺被证明是活化PMS最有效的金属离子。然而,Co以均相的离子形式存在于溶液中是有一定毒性的。与Co²⁺诱导的均相催化体系相比,基于Co²⁺掺杂的MIL-53（Al）的非均相催化体系在对Co²⁺的高效利用的同时能避免金属浸出。本研究的目标是采用溶剂热一步法合成Co掺杂的MIL-53（Al）,并用其活化PMS去除水中的TC。在本研究中,基于Co和Al的不同摩尔比10%、15%、20%、25%,制备了不同Co掺杂含量的MIL-53（Al）。通过X射线衍射（XRD）、场发射扫描电镜（SEM）和傅里叶红外变换光谱（FTIR）、氮气吸附脱附、X射线电子能谱（XPS）、电感耦合等离子体质谱表征（ICP-MS）表征表明了Co-MIL-53（Al）样品的成功合成。去除TC效果最佳的材料25%Co-MIL-53（Al）呈现立方长条状,平均直径为75 nm,比表面积是905.02 m2g-1。25%Co-MIL-53（Al）/PMS非均相催化体系对TC的去除效果优于单独的PMS和MIL-53（Al）/PMS系统,并且Co掺杂量越高效果越好。捕获实验与电子顺磁共振（EPR）测试表明Co-MIL-53（Al）活化PMS降解四环素主要是由于硫酸根自由基(SO₄^·-)和单线态氧（¹O₂）非自由基的作用。识别了TC的7种降解中间产物,提出了TC两条可能的降解途径。PMS添加剂量适当提高到30 mg时,Co-MIL-53（Al）/PMS体系去除TC效果变好,再增加到40 mg因为活性物质自猝灭作用反而降低效果。Co-MIL-53（Al）/PMS体系具有良好的稳定性,在溶液初始p H为3-11范围内对TC均有良好的去除效果,在合成样品Co-MIL-53（Al）四次循环后仍能去除80%的TC,几乎不受共存物质例如腐殖酸（HA）、NO₃^-、Cl^-和CO₃^2-的影响,并且在实际水体条件下（自来水、湘江水、制药废水）仍具有优异的催化性能。这些结果表明,Co-MIL-53（Al）是一种很有前途的可用于活化PMS降解水中四环素的非均相催化剂。更多还原

【Abstract】 Tetracycline（TC）is widely used in the medical and animal husbandry industries because of its antibacterial effect.However,in recent years,due to the unreasonable disposal of wastewater containing TC,the pollution to the environment and the harm to human beings had become more serious.It is difficult for traditional water treatment methods to remove TC completely,so it is necessary to develop efficient methods to treat TC wastewater.At present,advanced oxidation technology based on sulfate radical(SO₄^·-)has attracted wide attention because of its good catalytic effect.The activation of permonosulfate can produce SO₄^·-and Co²⁺is proved to be the most effective metal ion for activating PMS.However,the presence of Co²⁺in solution as homogeneous ions is toxic to a certain extent.Compared with the homogeneous catalytic system induced by Co²⁺,the heterogeneous catalytic system based on Co-doped MIL-53（Al）is stable for the efficient utilization of Co²⁺and avoiding the Co²⁺leaching.The aim of this work is to synthesize Co-doped MIL-53（Al）by one-step solvent thermal method and use it to activate PMS to remove TC in water.In this study,MIL-53（Al）with different Co doping content was prepared based on the different molar ratios of Co and Al of 10%,15%,20%and 25%.The results of X-ray diffraction（XRD）,field emission scanning electron microscopy（FE-SEM）,Fourier transform infrared spectroscopy（FTIR）,nitrogen adsorption and desorption,X-ray electron spectroscopy（XPS）and inductively coupled plasma mass spectrometry（ICP-MS）indicated that the Co-MIL-53（Al）samples were successfully synthesized.25%Co-MIL-53（Al）with the best TC removal effect presented a cubic strip with an average diameter of 75 nm and a specific surface area of 905.02m²g^-1.The removal effect of TC in 25%Co-MIL-53（Al）/PMS heterogeneous catalytic system is better than that of PMS alone and MIL-53（Al）/PMS system.The higher the doping amount of Co,the better the removal effect.Quenching experiments and electron paramagnetic resonance（EPR）tests showed that Co-MIL-53（Al）activating PMS to degrade TC was mainly due to the action of sulfate radical(SO₄^·-)and singlet oxygen（¹O₂）non-radical.The catalytic performances of Co-MIL-53（Al）/PMS system in conditions of different p H,co-existing substances and water bodies were investigated.Quenching experiments and electron paramagnetic resonance（EPR）showed that the degradation mechanism by Co-MIL-53（Al）activation PMS was mainly attributed to SO₄^·-and singlet oxygen（¹O₂）non-radical.Seven degradation intermediates of TC were identified,and two possible degradation pathways of TC were proposed.Co-MIL-53（AL）/PMS system had a better TC removal effect when the addition dose of PMS was appropriately increased to 30mg,but the effect was decreased when the addition dose was increased to 40mg because of the self-quenching effect of active substances.Co-MIL-53（Al）/PMS system had good stability:this system had good removal effect on TC in the initial p H range of 3-11.80%of TC could still be removed after four cycles of synthetic sample Co-MIL-53（Al）using,and it was almost not affected by the coexisting substances such as humic acid（HA）,NO₃^-,Cl^-and CO₃^2-.Moreover,it still had excellent catalytic performance under actual water conditions（tap water,Xiang River water,pharmaceutical wastewater）.These results indicate that Co-MIL-53（Al）is a promising heterogeneous catalyst for the activation of PMS to degrade TC in water.更多还原