【作者】 王园园；

【导师】 龚正君；

【作者基本信息】 西南交通大学 ， 环境科学与工程， 2024， 硕士

【摘要】 近年来,四环素类抗生素（TCs）在细菌感染防治方面应用广泛,TCs抗生素废水的深度净化需求迫在眉睫,亟待开发高效的催化剂和相关技术实现TC的高效降解。近些年,基于过硫酸盐活化的高级氧化技术因硫酸根自由基(SO₄^·-)的强氧化性而受到广泛关注,在四环素等抗生素废水的处理中极具应用潜力。已有研究表明,过渡金属氧化物可以作为有效的催化剂,活化过硫酸盐产生SO₄^·-,实现抗生素的高效降解。但过渡金属催化剂在面向实际应用中仍面临以下问题,如高价金属还原的热力学不利性导致金属活性位点的可循环性差,及粉末型材料的分离与回收等难题。基于此,本研究开发了基于尖晶石铁氧体的固载型复合阴极,构建了电辅助尖晶石铁氧体协同活化过一硫酸盐（PMS）降解TC的体系。此研究旨在为电辅助尖晶石铁氧体活化过硫酸盐降解TC的应用提供坚实的理论依据及实践指导。研究的主要内容及结论如下:首先,使用水热法在泡沫镍基底上沉积反相尖晶石NiFe₂O₄,经管式炉中退火后得到NiFe₂O₄/NF复合阴极。采用SEM、EDS、XRD、FT-IR、EIS及CV等表征测试方法研究了阴极的表面形貌、晶体结构、表面官能团及电化学活性等物化性质。以NiFe₂O₄/NF作为阴极,铂片作为阳极,PMS为氧化剂,构建了电辅助NiFe₂O₄/NF复合阴极催化剂活化PMS体系。结果表明,该体系在电流密度为2.5 m A/cm²、PMS剂量为1.0 m M和天然p H值的最佳运行条件下,对TC（30 mg/L）的去除率在60 min可达到81.7%,显著优于其他氧化对照体系,如EC、NiFe₂O₄/NF和PMS的单独及二元组合体系。空气和N₂氛围下的自由基猝灭实验表明SO₄^·-、·OH、O₂^·-和¹O₂等活性物种参与了TC的降解,其中¹O₂作用效果最为显著。上述活性物种被证实主要来源于PMS活化、原位产生的H₂O₂和电极反应。此外,反应前后NiFe₂O₄/NF化学价态的分析结果表明,电化学的引入不仅促进了金属活性位点的离子扩散,还促进了金属活性位点电子转移和氧化还原循环,电化学协同提高了非均相PMS活化体系的整体活性和稳定性。EC-NiFe₂O₄/NF-PMS系统还对共存物质表现出极强的抗干扰能力,在实际水体中对TC仍表现出良好的降解效能,且经过五次循环使用后对TC的降解效率依然保持在70.0%以上,这表明该体系在TC降解中具有良好的实际应用潜力。通过尖晶石铁氧体中的离子替代机制,在正相尖晶石ZnFe₂O₄掺杂Mn离子,考察多元金属协同催化活化过硫酸盐降解抗生素的效能与机制。具体为用水热法在泡沫镍基底上负载不同Fe/Mn比的正相尖晶石,并在管式炉中退火,得到ZnFe_2-xMn_xO₄/NF复合催化剂。采用SEM、XRD、FT-IR、EIS及CV等表征测试方法研究了阴极的表面形貌、晶体结构、表面官能团及电化学活性等物化性质。表征结果得出,与ZnFe₂O₄相比,Mn离子的掺杂并未改变样品的尖晶石型结构,推断出Mn离子成功地替换了部分Fe离子,并融入了尖晶石晶体结构中,在所有材料中ZnFe_0.5Mn_1.5O₄/NF的电化学活性最高。以ZnFe_2-xMn_xO₄/NF作为阴极,铂片作为阳极,PMS为氧化剂,构建了电辅助ZnFe_2-xMn_xO₄/NF复合阴极催化剂活化PMS体系。结果表明,当ZnFe_0.5Mn_1.5O₄/NF作阴极时,该体系在电流密度为2.5 m A/cm²、PMS剂量为1.0 m M和天然p H值的最佳条件下运行,对TC（30 mg/L）的去除率在60 min可达到81.3%,显著优于其他氧化对照体系,如EC、ZnFe_0.5Mn_1.5O₄/NF和PMS的单独及二元组合体系。自由基猝灭实验表明SO₄^·-、·OH、O₂^·-和¹O₂均参与了TC降解,其中¹O₂起关键作用,推测¹O₂可来源于SO₄^·-、·OH、O₂^·-的转化。此外,反应前后ZnFe_0.5Mn_1.5O₄/NF化学价态的分析结果表明,电化学的引入促进了金属活性位点电子转移和氧化还原循环。EC-ZnFe_0.5Mn_1.5O₄/NF-PMS系统还对共存物质表现出极强的抗干扰能力,经过五次循环使用后对TC的降解效率依然保持在65.0%以上,彰显出优异的重复使用性能,以上结果进一步拓展了尖晶石铁氧体在TC降解中的应用。最后,为了将催化剂真正地应用在实际污水处理中,搭建了连续流反应器,以ZnFe_0.5Mn_1.5O₄/NF作为阴极,铂片作为阳极,PMS为氧化剂,构建了电辅助ZnFe_0.5Mn_1.5O₄/NF复合阴极催化剂活化PMS连续流体系。结果表明,在水力停留时间为15 min、电流密度为2.5 m A/cm²、PMS剂量为0.8 m M和天然p H值的最佳条件下运行,对TC（30 mg/L）的去除率在可稳定在81.6%,且连续运行400 min后TC的降解率始终保持在80%以上,这表明材料在连续流条件下对TC的降解体现出良好的稳定性,该连续流装置在处理实际水样时同样展现了卓越的降解效率,以上结果也为体系的实际应用提供了坚实的理论依据及实践指导。更多还原

【Abstract】 In recent years,tetracycline antibiotics（TCs）have been extensively employed in the prevention and treatment of bacterial infections.The urgent need for advanced purification of tetracycline antibiotic wastewater necessitates the development of efficient catalysts and technologies for the effective degradation of TCs.Advanced oxidation processes（AOPs）based on persulfate activation have garnered widespread attention due to the strong oxidizing properties of sulfate radical anions(SO₄^·-),demonstrating significant potential in the treatment of antibiotic wastewater,including tetracyclines.Studies have indicated that transition metal oxides can serve as effective catalysts,activating persulfates to generate SO₄^·-and achieve efficient antibiotic degradation.However,transition metal catalysts still face several challenges in practical applications,such as the thermodynamic disadvantages of high-valent metal reduction leading to poor recyclability of active metal sites,and difficulties in the separation and recovery of powder-type materials.Based on these issues,this study developed a fixed composite cathode based on spinel ferrite,constructing an electrically-assisted system for PMS activation and TC degradation using spinel ferrite.This research aims to provide a solid theoretical basis and practical guidance for the application of electrically-assisted spinel ferrite in activating persulfate for TC degradation.The main contents and conclusions of the study are as follows:Initially,inverse spinel NiFe₂O₄ was deposited on a nickel foam substrate using a hydrothermal method,followed by annealing in a tube furnace to obtain the NiFe₂O₄/NF composite cathode.The cathode’s surface morphology,crystal structure,surface functional groups,and electrochemical activity were studied using SEM,EDS,XRD,FT-IR,EIS,and CV.Using NiFe₂O₄/NF as the cathode,a platinum sheet as the anode,and PMS as the oxidant,an electrically-assisted catalyst system for PMS activation was constructed.Results demonstrated that under optimal operating conditions of 2.5 m A/cm²current density,1.0m M PMS dosage,and natural p H,the system achieved an 81.7%removal rate for TC（30mg/L）within 60 minutes,significantly outperforming other oxidation control systems such as EC,NiFe₂O₄/NF alone,and binary combinations with PMS.Radical quenching experiments in air and N₂atmospheres showed that reactive species like SO₄^·-,·OH,O₂^·-,and ¹O₂were involved in TC degradation,with ¹O₂having the most significant effect.These reactive species were primarily derived from PMS activation,in-situ generated H₂O₂,and electrode reactions.Furthermore,analysis of the chemical valence states of NiFe₂O₄/NF before and after the reaction revealed that the introduction of electrochemistry not only facilitated ion diffusion at the metal active sites but also enhanced electron transfer and redox cycling,synergistically improving the overall activity and stability of the heterogeneous PMS activation system.The EC-NiFe₂O₄/NF-PMS system also demonstrated strong anti-interference capability against co-existing substances,maintaining a degradation efficiency for TC above 70.0%after five cycles of use,indicating the system’s substantial practical application potential in TC degradation.Through the ion substitution mechanism in spinel ferrites,ZnFe₂O₄doped with Mn ions was explored for the multi-metal synergistic catalytic activation of persulfate for antibiotic degradation.Using a hydrothermal method,different Fe/Mn ratios of normal spinel were loaded onto a nickel foam substrate and annealed in a tube furnace to obtain the ZnFe_2-xMn_xO₄/NF composite catalyst.Characterization studies of the cathode’s surface morphology,crystal structure,surface functional groups,and electrochemical activity using SEM,XRD,FT-IR,EIS,and CV revealed that Mn ion doping did not alter the spinel structure of the samples,suggesting successful substitution of some Fe ions and integration into the spinel crystal structure,with ZnFe_0.5Mn_1.5O₄/NF showing the highest electrochemical activity.Using ZnFe_2-xMn_xO₄/NF as the cathode,a platinum sheet as the anode,and PMS as the oxidant,an electrically-assisted composite cathode catalyst system for PMS activation was constructed.Results indicated that when ZnFe_0.5Mn_1.5O₄/NF served as the cathode,the system achieved an 81.3%removal rate for TC（30 mg/L）within 60minutes under optimal conditions of 2.5 m A/cm²current density,1.0 m M PMS dosage,and natural p H,markedly surpassing other oxidation control systems such as EC,NiFe₂O₄/NF alone,and binary combinations with PMS.Radical quenching experiments indicated the involvement of SO₄^·-,·OH,O₂^·-,and ¹O₂in TC degradation,with ¹O₂playing a key role,presumably arising from the transformation of SO₄^·-,·OH,and O₂^·-.Additionally,analysis of the chemical valence states of ZnFe_0.5Mn_1.5O₄/NF before and after the reaction showed that the introduction of electrochemistry promoted electron transfer and redox cycling at the metal active sites.The EC-ZnFe_0.5Mn_1.5O₄/NF-PMS system also exhibited strong anti-interference capability against co-existing substances,maintaining a degradation efficiency for TC above 65.0%after five cycles of use,showcasing superior repeatability,and further expanding the application of spinel ferrites in TC degradation.Lastly,to apply the catalyst in actual wastewater treatment,a continuous flow reactor was constructed using ZnFe_0.5Mn_1.5O₄/NF as the cathode,a platinum sheet as the anode,and PMS as the oxidant,creating an electrically-assisted continuous flow system for PMS activation.Results showed that under optimal conditions of 15 minutes hydraulic retention time,2.5 m A/cm²current density,0.8 m M PMS dosage,and natural p H,the system consistently achieved over 81.6%TC removal rate（30 mg/L）,maintaining a degradation rate above 80%even after 400 minutes of continuous operation.This demonstrated the material’s stability under continuous flow conditions and its excellent degradation efficiency in handling actual water samples,providing solid theoretical support and practical guidance for the system’s real-world application.更多还原