铜铁氧化物复合碳纳米管催化剂的合成、表征和活性研究

发布时间：2018-04-08 16:27

本文选题：硫酸根自由基　切入点：铜铁氧化物复合碳纳米管　出处：《南京大学》2017年硕士论文

【摘要】：基于硫酸根自由基(SO_4~(·-))的高级氧化技术在有机污染物的降解中有着良好的应用前景。两种典型氧化剂过硫酸盐(PS)和过一硫酸盐(PMS)易产生高反应活性的SO_4~(·-)(2.5-3.1V),高于羟基自由基(2.2-2.7V)的氧化性。且具有稳定性好、利用率高、反应不受碳酸盐和氯化物等无机盐干扰等优点。据报道铜铁氧化物(CuFe_2O_4)可以高效催化活化氧化剂PMS,然而对于PS的激活作用研究较少。再者,通过引入共催化剂,可进一步提高CuFe_2O_4对于氧化剂的催化活化效率。因此,本研究着眼于铜铁氧化物的复合催化剂的设计与合成,并研究了其在催化活化PS和PMS中的作用机理,最终成功地应用于氧化降解两种典型环境内分泌干扰物邻苯二甲酸二乙酯(DEP)和2-苯基苯并咪唑-5-磺酸(PBSA)。(1)利用凝胶-混凝法将CuFe_2O_4负载到碳纳米管上制备催化剂CuFe_2O_4/MWCNTs,并将其应用于DEP的催化降解。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、BET(Brunauer-Emmett-Teller)比表面积分析、X射线电子能谱学(XPS)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)等方法对催化剂进行性能表征。此外,系统研究催化PS降解DEP的多种影响因素(催化剂的负载量,PS浓度,温度和pH)。实验结果表明,CuFe_2O_4/MWCNTs在DEP去除过程中表现出较高的催化活性及可回收利用性。特别指出的是,利用原子吸收光谱检测到CuFe_2O_4/MWCNTs在使用过程中的金属离子溶出率极低(浓度0.4%),表明了该催化剂具有高稳定性。电子顺磁共振分析(EPR)确认了 CuFe_2O_4/MWCNTs能够加快PS分解产生SO_4~(·-);淬灭实验结果进一步证明了在该催化反应中SO_4~(·-)起主导作用。此外,通过对降解产物的鉴定提出了可能的降解路径。(2)基于理性设计,利用共沉淀法负载CuFe_2O_4于氮和硫共掺杂的多壁碳纳米管上,合成了催化剂NS-CNTs/CuFe_2O_4,并将其应用于催化PMS氧化PBSA(一种典型的防晒剂添加剂)。在本研究中,我们对此催化剂进行了系统地性能表征,包括SEM、TEM、BET比表面积分析、XPS、XRD、FT-IR等,进一步展示了其晶体结构,目标元素以及官能团的存在等。然后系统研究了该污染物的降解动力学,降解产物及可能的反应路径,以及NS-CNTs/CuFe_2O_4催化PMS降解PBSA的机理。实验结果表明该催化剂在催化PMS降解PBSA中具有良好的催化活性,稳定性和可回收利用性。EPR和淬灭实验结果表明PMS被NS-CNTs/CuFe_2O_4降解过程中SO_4~(·-)起到主导作用。此外,CuFe_2O_4与NS-CNTs在激活PMS过程中存在联合的催化机制。最后,由LC-MS鉴别出PBSA的8种降解产物且进一步提出其降解路径。总之,该研究为NS-CNTs/CuFe_2O_4催化PMS氧化PBSA提供了参考资料。
[Abstract]:Based on sulfate radical (SO_4~ (-)) advanced oxidation technology has good application prospects in the degradation of organic pollutants. Two typical oxidant persulfate (PS) and sulfate (PMS) is easy to produce the high activity of SO_4~ (-) (2.5-3.1V), higher than that of hydroxyl free radical (2.2-2.7V) oxidation. And it has good stability, high utilization rate, the advantages of the reaction against carbonate and chloride interference. According to reports of copper and iron oxide (CuFe_2O_4) can catalyze the activation of oxidant PMS, but for PS activation research. Furthermore, by introducing the co catalyst to further to improve the CuFe_2O_4 for catalytic oxidation of activated agent efficiency. Therefore, the design and synthesis of composite catalyst, this study focuses on copper and iron oxide, and studied its mechanism of activation of PS and PMS in catalysis, finally successfully applied to oxidative degradation of two The typical environmental endocrine disruptors phthalate two formic acid ethyl ester two (DEP) and 2- -5- phenylbenzimidazole sulfonic acid (PBSA). (1) coagulation method to load CuFe_2O_4 to the catalyst CuFe_2O_4/MWCNTs carbon nanotube by gel, and its application in the photocatalytic degradation of DEP. By using scanning electron microscopy (SEM), transmission electron microscope (TEM), BET (Brunauer-Emmett-Teller) surface area analysis, X - ray photoelectron spectroscopy (XPS), X ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) method of the catalyst. In addition, the effect of various factors on the catalytic degradation of PS system DEP (catalyst loading. The concentration of PS, temperature and pH). The experimental results show that the CuFe_2O_4/MWCNTs in the DEP removal process showed higher catalytic activity and Recyclable utilization. In particular, the absorption spectrum of CuFe_2O_4/MWCNTs is detected in the process of using atomic The metal ions in the dissolution rate is very low (0.4% concentration), show that the catalyst has high stability. Electron paramagnetic resonance (EPR) confirmed that CuFe_2O_4/MWCNTs can accelerate the decomposition of SO_4~ (PS -); quenching experiment results prove that the SO_4~ in the catalytic reaction of (-) play a leading role. In addition, through the identification of degradation products presents a possible degradation pathway. (2) based on the rational design, the use of multi walled carbon nanotube CuFe_2O_4 in nitrogen and sulfur doped co precipitation method, catalyst NS-CNTs/CuFe_2O_4 was synthesized and applied to catalyze the oxidation of PMS PBSA (a kind of typical sunscreen additives). In this study, we have characterized the performance system, including SEM, TEM, BET surface area analysis, XPS, XRD, FT-IR and so on, to further demonstrate its crystal structure, the target element and the existence of functional groups. Then system. The degradation kinetics of the pollutants, degradation products and the possible reaction paths, and the mechanism of NS-CNTs/CuFe_2O_4 catalytic degradation of PMS PBSA. The experimental results show that the catalyst has good catalytic activity in the catalytic degradation of PMS in PBSA, the stability and Recyclable use.EPR and quenching experiment results show that the PMS is SO_4~ NS-CNTs/CuFe_2O_4 in the degradation process (. -) play a leading role. In addition, CuFe_2O_4 and NS-CNTs are combined with the catalytic mechanism in the activation process of PMS. Finally, identified by LC-MS PBSA of the 8 kinds of degradation products and further put forward the degradation path. Overall, this study provides a reference for the oxidation of PMS NS-CNTs/CuFe_2O_4 PBSA.

【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;O643.36

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