【作者】 张林；

【导师】 王松林；

【作者基本信息】 华中科技大学 ， 市政工程（含给排水等）（专业学位）， 2024， 硕士

【摘要】 零价铁（ZVI）作为一种来源广泛、成本低廉且环境友好的过渡金属,在基于过硫酸盐（PS）的高级氧化技术中备受研究者青睐。然而零价铁在活化过硫酸盐的反应过程中却存在易氧化、易团聚、易腐蚀、电子选择性差等缺点。因此,本研究利用液相还原法和一步硫化法制备纳米零价铁（nZVI）和硫化纳米零价铁（S-nZVI）,构建了S-nZVI/PS体系,系统地研究了S-nZVI催化剂活化PS对阿特拉津（ATZ）的去除效果,考察各关键反应条件参数对该体系的影响,并设计一系列实验和表征方法探究了S-nZVI/PS体系的反应机理;最后,考察了S-nZVI/PS体系在不同自然水体中处理不同有机污染物的效果,评估该体系的工程实际应用潜力。主要研究成果如下:（1）催化剂的制备与表征和S-nZVI/PS体系去除ATZ的效果研究。采用液相还原法制备了nZVI和S-nZVI,并用SEM、XRD、BET和XPS等表征方法分析了催化剂的理化特性;在硫铁比（S/Fe）为0.025、催化剂投加量为0.04 g/L、PS浓度为0.4m M、初始p H值为3.0、温度为25℃的最佳实验条件下,反应40 min后S-nZVI/PS体系对ATZ的去除率达到92.5%;水中的SO₄^2-、NO₃^-离子对ATZ的去除基本无影响,HCO₃^-、HPO₄^2-和腐殖酸（HA）对ATZ的去除有抑制作用,而溶液中的Cl^-会促进S-n ZVI/PS体系对ATZ的去除效果;此外,不同反应条件下ATZ的降解过程更符合拟二级动力学模型。（2）S-n ZVI/PS体系去除ATZ的机理研究。采用淬灭实验和电子顺磁共振波谱实验（EPR）分析了S-nZVI/PS体系中产生的活性物种,证明S-n ZVI/PS体系中产生了硫酸根自由基(SO₄^·-)、羟基自由基（·OH）、高价铁（Fe（Ⅳ））和单线态氧（¹O₂）,且SO₄^·-、·OH和Fe（Ⅳ）对ATZ降解的贡献比例分别为48.2%、35.1%和16.7%,¹O₂对ATZ降解几乎没有贡献;明晰了硫化改性能促进体系中SO₄^·-、·OH、Fe（Ⅳ）等活性物种的生成,揭示了反应过程中铁的循环机制和硫的转化机制;理论计算结合中间产物分析,阐明了ATZ的降解过程主要包括脱烷基、脱氯和羟基化。（3）S-n ZVI/PS体系的适用性研究。在催化剂投加量为0.10 g/L,PS浓度为2mM,初始p H值为3.0,温度为25℃的最佳实验条件下,反应60 min后S-nZVI/PS体系对磺胺甲噁唑（SMX）的去除率达到88.9%;在同等反应条件下,对乙酰氨基酚（ACE,10 mg/L）和甲基异噻唑啉酮（MIT,10mg/L）的去除率在10 min内达到99%;且该体系在两种自然水体中也能对SMX保持较好的去除效果,在实际处理有机废水时有一定的应用潜力。更多还原

【Abstract】 Zero valent iron,a transition metal known for its wide availability,low cost,and eco-friendly nature,is a preferred choice for researchers in persulfate-based advanced oxidation technologies.Despite its advantages,ZVI is susceptible to oxidation,aggregation,corrosion,and lacks electron selectivity when activating persulfate.To solve these problems,this study employed liquid-phase reduction and one-step vulcanization methods to synthesize nano zero valent iron（nZVI）and sulfurized nano zero valent iron（S-nZVI）.The research focused on constructing an S-nZVI/PS system and examining the efficiency of atrazine（ATZ）removal by activating PS with S-nZVI catalyst.Various key reaction condition parameters were analyzed,along with a series of experiments and characterization methods to investigate the reaction mechanism of the S-nZVI/PS system.Subsequently,the effectiveness of the S-nZVI/PS system in treating diverse organic pollutants in different natural water bodies was assessed,providing insights into the system’s potentiality for practical engineering applications.The primary research results are as follows:（1）The preparation and characterization of catalysts and the efficiency of S-nZVI/PS system in removing ATZ have been investigated.S-nZVI and nZVI were synthesized using liquid-phase reduction and one-step vulcanization methods.The catalyst’s physicochemical properties were characterized through SEM,XRD,BET,and XPS analyses.Optimal experimental conditions,including a sulfur iron ratio（S/Fe）of 0.025,catalyst dosage of0.04 g/L,PS concentration of 0.4 mM,initial pH of 3.0,and temperature of 25℃,resulted in a 92.5%removal rate of ATZ after 40 minutes of reaction.Meanwhile,the presence of SO₄^2-and NO₃^-ions did not significantly impact ATZ removal,while HCO₃^-,HPO₄^2-,and humic acid（HA）exhibited inhibitory effects.Moreover,Cl^-in the solution would promote the removal effect of ATZ by the system.Kinetic modeling indicated that the degradation of ATZ in the S-n ZVI/PS system aligned more closely with a pseudo second-order kinetic model under various reaction conditions.（2）The mechanism of S-nZVI/PS system for removing ATZ has been investigated.The active species generated in the S-nZVI/PS system were analyzed through quenching experiments and electron paramagnetic resonance spectroscopy experiment（EPR）.The study revealed the production of hydroxyl radicals（·OH）,sulfate radicals(SO₄^·-),singlet oxygen（¹O₂）,and high valent iron（Fe（IV））in the S-n ZVI/PS system.The contribution ratios of·OH,SO₄^·-,and Fe（IV）to ATZ degradation were determined to be 35.1%,48.2%,and 16.7%,respectively,with ¹O₂ showing minimal impact on ATZ degradation.The vulcanizability promoted the formation of active species such as SO₄^·-,·OH and Fe（Ⅳ）in the system,and revealed the cycling mechanism of iron and the transformation mechanism of sulfur during the reaction.The theoretical calculation combined with the analysis of intermediate products showed that the degradation process of ATZ mainly included dealkylation,dechlorination and hydroxylation.（3）The applicability of the S-nZVI/PS system has been investigated.Optimal experimental conditions included a catalyst dosage of 0.10 g/L,PS concentration of 2 mM,initial pH value of 3.0,and temperature of 25℃,resulting in an 88.9%removal rate of SMX after 60 minutes of reaction.Furthermore,the S-nZVI/PS system demonstrated consistent removal efficiency for SMX in various natural water bodies.Additionally,under the same conditions,acetaminophen（ACE,10 mg/L）and methylisothiazolinone（MIT,10mg/L）were efficiently degraded by the S-n ZVI/PS system,achieving a degradation rate of over 99%within 10 minutes.There is certain potential for application in the actual treatment of organic wastewater.更多还原