【作者】 李超；

【导师】 叶立群； 林高；

【作者基本信息】 三峡大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 随着工业生产技术的提高和社会的飞速发展,造成的水资源污染问题日益严重。而常规的污水处理工艺很难将这些成分复杂的污染物有效去除,化学高级氧化法因其具有操作方便,降解速率快,二次污染小等优势被国内外学者广泛研究,对于大规模的废水处理和水资源问题,利用过硫酸盐的高级氧化技术提供了一条重要的途径。基于过一硫酸盐（PMS）的高级氧化技术因其反应速度快、p H适应范围广等优点,引起了水处理研究人员的广泛关注。产生的活性物种具有较强的氧化能力,表现出优异的抗污染物和细菌性能。因此,本论文聚焦于过渡金属催化剂,在保证其稳定高效活化过硫酸盐的同时,对其活化机理进行深入的探究。本文的主要研究结果如下:基于目前过硫酸盐体系的稳定性和扩展性问题,通过简便的化学沉积法（CVD）法制备了碳纳米管包覆钴（Co-NC）膜,进一步构建流动反应器的PMS催化系统。对大肠杆菌（E.coli）的杀菌效率达99.99%,对于金黄色葡萄球菌也表现出100%的灭活活性,并在40次重复循环后仍保持96.29%的优越稳定性。此外,在362 L m^-2 h^-1。723 L m^-2 h^-1、1448 L m^-2 h^-1的高通量下测试Rh B中,其平均可以达到92.5%的降解效率。ICP测试了其6次过滤反应后溶液中Co离子浓度平均仅为7μg/L。还测试了不同实验条件（包括浓度、p H值、流速、无机阴离子的存在和腐植酸浓度）对于对E.coli的杀菌影响。将Co-NC/PMS系统的装置扩展到秋溪水。在连续12小时的真实污水处理中,其灭活效率也达到了99.99%。机理实验表明Co-NC膜大多数Co元素是以Co金属纳米颗粒的形式的,被氧化形成高价的Co金属（Co^Ⅳ=O）作为主要活性物种。SO₄?^-和¹O₂作为次级物种。在水流过程中,Co-NC膜被用作PMS和细菌之间反应的催化平台,活性物种将首先攻击细胞壁/膜并引起脂质过氧化,导致细胞膜的破坏。然后破坏了细胞内的防御系统,随后大量的钾离子被浸出,进一步导致细胞溶解。细胞呼吸也被打断,能量供应逐渐丧失,这反过来又影响了细胞的活力,导致关键的细胞功能（核酸）丧失,最终细胞完全失活。针对目前过硫酸盐体系的成本和效率问题,通过共沉淀热法合成了高熵合金氧化物（HEOs）,并且将HEOs成功运用于活化过硫酸盐体系,表现优异的降解效果。实验表明降解ATZ、BPA、RHB、TC等有机污染物在5min内都达到96%以上的去除率。HEOs在灭活细菌方面也可以达到几乎100%的灭活性能。随后又进行环境耐性测试证明HEOs/PMS具有实际水净化的应用潜力。并设计了HEOs-纤维球/PMS反应装置,测试了在水力停留时间约1s、流量为362 L m^-2 h^-1的情况下连续水净化的性能,HEOs-纤维球/PMS在流动运行模式下的系统表现出稳定的处理性能,连续运行期间TC去除率可达92.7%。电化学实验证明PMS与HEOs表面形成过渡态PMS*的形成,此外,DFT结果证明了HEOs（010）面上（Zn Co）与PMS有较强的吸附能,差分电荷证明了HEOs与PMS有较强的相互作用能力。通过Co-Mn超交换相互作用和协同作用增强HEOs/PMS活性和调节途径的分子机制。更小的电化学阻抗地促进了电荷的传输。活性物种测试了Co ^IV/Mn ^V是HEOs/PMS系统中产生的主要活性物种。HEOs在活化PMS方面也表现90.21%非自由选择性。更多还原

【Abstract】 With the improvement of industrial production technology and the rapid development of society,the pollution of water resources is becoming more and more serious.While conventional wastewater treatment processes are difficult to remove these pollutants with complex compositions effectively,chemical advanced oxidation has been widely studied by domestic and foreign scholars for its advantages of easy operation,fast degradation rate and small secondary pollution,etc.Advanced oxidation technology using peroxymonosulfate is an important way for large-scale wastewater treatment and water resources problems.The advanced oxidation technology based on peroxymonosulfate（PMS）has attracted a lot of attention from water treatment researchers because of its advantages such as fast reaction rate and wide p H adaptation range.The generated reactive species have a strong oxidation capacity and exhibit excellent anti-pollutant and bacterial properties in terms of free and non-free radicals.Therefore,this thesis focuses on transition metal catalysts to ensure their stable and efficient activation of persulfate while providing an in-depth investigation of their activation mechanisms.The main findings of this paper are as follows:Based on the stability and scalability problems of the current persulfate system,carbon nanotube-coated cobalt（Co-NC）membranes were prepared by Chemical vapor deposition（CVD）to further construct a PMS catalytic system for flow reactors.The bactericidal efficiency against Escherichia coli（E.coli）was 99.99%,and it also showed 100%inactivation activity for Staphylococcus aureus,respectively,maintaining a superior stability of 96.29%after 40 repeated cycles.In addition,it reaches an average degradation efficiency of 92.5%at 362 L m^-2 h^-1.723 L m^-2 h^-1,1448 L m^-2 h^-1 for organic pollutants（Rh B）tested at high fluxes.The effect of different experimental conditions（including concentration,p H,flow rate,presence of inorganic anions and humic acid concentration）on the bactericidal activity of E.coli was also tested.The installation of the Co-NC/PMS system was extended to Autumn Creek water.The inactivation efficiency also reached 99.99%in a real wastewater treatment for 12 consecutive hours.Mechanistic experiments showed that most of the Co elements of the Co-NC membrane were in the form of Co metal nanoparticles,which were oxidized to form high-valent Co metal(Co ^IV=O)as the primary active species.SO₄^?-and ¹O₂ as secondary species.During water flow,the Co-NC membrane is used as a catalytic platform for the reaction between the PMS and the bacteria,and the active species will first attack the cell wall/membrane and cause lipid peroxidation,leading to the breakage of the cell membrane.The intracellular defense system is then disrupted,followed by leaching of large amounts of potassium ions,which further leads to cell lysis.Cellular respiration is also interrupted and energy supply is gradually lost,which in turn affects cell viability,leading to loss of key cellular functions（nucleic acids）and eventually complete cellular inactivation.To address the cost and efficiency problems of the current persulfate system,high-entropy alloy oxides（HEOs）were synthesized by co-precipitation thermal method,and HEOs were applied to activate the persulfate system with excellent degradation effect.The experiments showed that the degradation of ATZ,BPA,RHB,TC and other organic pollutants achieved more than 96%removal rate within 5 min.HEOs could also achieve almost 100%inactivation performance in terms of bacteria.Subsequently,environmental resistance tests were conducted to show that HEOs/PMS showed potential for practical water purification applications.The HEOs-fiber spheres/PMS reactor was designed and tested for continuous water purification at a hydraulic retention time of about 1 s and a flow rate of 362 L m^-2 h^-1.The HEOs-fiber spheres/PMS system in flow operation mode showed stable treatment performance with TC removal rates of 92.7%during continuous operation.Electrochemical experiments show that PMS form transition state PMS*on the surface of HEOs.In addition,the DFT results proved that（Zn Co）on the surface of HEOs（010）had strong adsorption energy with PMS,and the differential charge proved that HEOs had strong interaction ability with PMS.Molecular mechanisms of enhanced HEOs/PMS activity and regulatory pathways through Co-Mn superexchange interactions and synergistic interactions.Smaller electrochemical impedance ground facilitates charge transport.Active species tested were Co^IV/Mn^V as the main active species generated in the HEOs/PMS system.HEOs also exhibited 90.21%non-free selectivity in activating PMS.更多还原