炭载金属氧化物粒子电极制备及其电催化氧化苯酚实验研究
发布时间：2019-02-15 21:48
【摘要】：填充床电化学水处理工艺是一种被环保工作者寄予厚望的水处理技术,而床层中填料的制备是该技术的主要研究方向之一,尤其是对于炭载金属氧化物粒子电极的全面评价及其催化氧化有机物机理的探究,将为炭载金属氧化物种类的比选提供依据。基于此,本研究以活性炭为载体,进行了Mn、Sn及Sb等单组份金属氧化物或复合型金属氧化物负载型粒子电极的制备,通过物化表征、苯酚氧化实验,充分研究了不同粒子电极的电催化氧化性能,也对其电催化氧化苯酚机理进行了探讨。主要结论如下:在填料的制备中,利用浸渍法制备了Mn O2/AC(后文简称锰型)、利用溶胶凝胶法制备了Sn O2-Sb Ox/AC(锡锑型)和Mn O2-Sn O2-Sb Ox/AC(锰锡锑型)。在物理表征中,SEM分析表明,三种填料负载物负载均匀,分散性好,无大块负载物团聚。XRD分析表明,锰型填料中二氧化锰的物相为α与β相相混合型;锡锑型中二氧化锡为四方晶系;锰锡锑型中,二氧化锰为β相,二氧化锡为四方晶系。BET分析表明,负载过后,比表面积及孔容孔径均有大范围下降,负载物侵占孔道能力较强,负载充分,其中以锰锡锑型最为显著。在电化学表征中,0~1.8V的循环伏安(CV)表明,锰锡锑型出现了氧化还原峰,推测为金属氧化物与过氧化物的氧化还原过程引起,填料的活性点位数较未负载的均有了明显的提高,三者差异不大。-0.1~0.6V的CV表明,填料负载过后,通过双电层电场氧化苯酚的能力均有了提高。极化曲线分析表明,在析氧电位方面,锰锡锑型优于锡锑型优于未负载型优于锰型;交换电流密方面,负载型普遍优于未负载型,锰锡锑型最为显著。交流阻抗的测试表明,在电荷转移电阻方面,锡锑型填料的电阻最小,其次为锰锡锑型,锰型,这三者均小于未负载型;在扩散控制方面,则是锰锡锑型扩散最具优势,其次为锡锑型,锰型。以填料做粒子电极,在填充床反应器内进行了苯酚废水水处理实验。水处理结果显示锰锡锑型填料的COD及苯酚浓度去除效果最优,其次为锡锑型、锰型及未负载型。UV分析来看,负载过后填料对苯酚的中间产物苯醌等闭环有机物的降解均有了提高,其中以锰型填料最优,其次为锰锡锑型、锡锑型。结合相关水处理指标及电化学表征等分析,在电化学水处理中,推测二氧化锰生成了Mn Ox+1,其促进了填料对苯酚及苯醌等闭环有机物的选择性氧化;推测二氧化锡型生成了Sn O2(?OH),其促进了填料对苯环等有机物的电化学燃烧。能耗及电流效率分析表明,锰锡锑型填料优势明显,其次锡锑型、锰型。
[Abstract]:The electrochemical water treatment process in packed bed is a kind of water treatment technology which is highly expected by environmental protection workers, and the preparation of the filler in the bed is one of the main research directions of the technology. In particular, the comprehensive evaluation of carbon-loaded metal oxide particle electrodes and the study of the mechanism of catalytic oxidation of organic compounds will provide the basis for the comparison and selection of carbon-loaded metal oxides. Based on this, the single component metal oxide or composite metal oxide supported particle electrodes, such as Mn,Sn and Sb, were prepared with activated carbon as the carrier, and were characterized by physicochemical characterization and phenol oxidation experiments. The electrocatalytic oxidation performance of different particle electrodes was studied and the mechanism of phenol oxidation was also discussed. The main conclusions are as follows: in the preparation of filler, Mn O2/AC (manganese type) was prepared by impregnation method, Sn O2-Sb Ox/AC (tin antimony type) and Mn O2-Sn O2-Sb Ox/AC (manganese tin antimony type) were prepared by sol-gel method. In physical characterization, SEM analysis showed that the three fillers had uniform loading, good dispersion and no agglomeration of bulk loads. XRD analysis showed that the phase of manganese dioxide in manganese type fillers was a mixture of 伪 and 尾 phase. Tin dioxide is tetragonal in antimony type. In the manganese-tin antimony type, manganese dioxide is 尾 phase and tin dioxide is tetragonal system. BET analysis shows that after loading, the specific surface area and pore volume pore size decrease in a wide range, and the load has a strong ability to encroach on the pore channel and has sufficient load. Among them, manganese, tin and antimony type is the most significant. In the electrochemical characterization, the cyclic voltammetry (CV) of 0 ~ 1.8V indicates that the oxidation and reduction peaks of manganese, tin and antimony type appear, which may be caused by the redox process of metal oxides and peroxides. The number of active sites of fillers was significantly higher than that of unloaded fillers, and the difference among the three was not significant. The CV of -0.1 ~ 0.6V showed that the ability of phenol oxidation by double-layer electric field was improved after the filler was loaded. The analysis of polarization curves shows that the manganese tin antimony type is superior to the unloaded type in oxygen evolution potential, and the load type is generally superior to the unloaded type in the exchange current density, and the manganese tin antimony type is the most significant. The measurement of AC impedance shows that the resistance of tin antimony type filler is the smallest, followed by manganese tin antimony type and manganese type in charge transfer resistance, which are all smaller than that of unloaded type. In the aspect of diffusion control, manganese, tin and antimony type have the most advantages, followed by tin antimony type and manganese type. Phenol wastewater treatment experiment was carried out in packed bed reactor with filler as particle electrode. The results of water treatment showed that the removal efficiency of COD and phenol was the best, followed by tin antimony type, manganese type and unloaded type. UV analysis showed that, After loading, the degradation of phenol intermediate products, such as benzoquinone, was improved, among which manganese filler was the best, followed by manganese tin antimony type and tin antimony type. Based on the analysis of related water treatment indexes and electrochemical characterization, it was suggested that manganese dioxide formed Mn Ox _ 1 in electrochemical water treatment, which promoted the selective oxidation of phenol and benzoquinone by fillers. It is inferred that tin dioxide type produces Sn O 2 (? OH),) which promotes the electrochemical combustion of benzene ring and other organic compounds. The analysis of energy consumption and current efficiency showed that Mn-Sn-Sb-type filler had obvious advantage, followed by Sn-Sb-type and Mn-type.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
本文编号：2423727
[Abstract]:The electrochemical water treatment process in packed bed is a kind of water treatment technology which is highly expected by environmental protection workers, and the preparation of the filler in the bed is one of the main research directions of the technology. In particular, the comprehensive evaluation of carbon-loaded metal oxide particle electrodes and the study of the mechanism of catalytic oxidation of organic compounds will provide the basis for the comparison and selection of carbon-loaded metal oxides. Based on this, the single component metal oxide or composite metal oxide supported particle electrodes, such as Mn,Sn and Sb, were prepared with activated carbon as the carrier, and were characterized by physicochemical characterization and phenol oxidation experiments. The electrocatalytic oxidation performance of different particle electrodes was studied and the mechanism of phenol oxidation was also discussed. The main conclusions are as follows: in the preparation of filler, Mn O2/AC (manganese type) was prepared by impregnation method, Sn O2-Sb Ox/AC (tin antimony type) and Mn O2-Sn O2-Sb Ox/AC (manganese tin antimony type) were prepared by sol-gel method. In physical characterization, SEM analysis showed that the three fillers had uniform loading, good dispersion and no agglomeration of bulk loads. XRD analysis showed that the phase of manganese dioxide in manganese type fillers was a mixture of 伪 and 尾 phase. Tin dioxide is tetragonal in antimony type. In the manganese-tin antimony type, manganese dioxide is 尾 phase and tin dioxide is tetragonal system. BET analysis shows that after loading, the specific surface area and pore volume pore size decrease in a wide range, and the load has a strong ability to encroach on the pore channel and has sufficient load. Among them, manganese, tin and antimony type is the most significant. In the electrochemical characterization, the cyclic voltammetry (CV) of 0 ~ 1.8V indicates that the oxidation and reduction peaks of manganese, tin and antimony type appear, which may be caused by the redox process of metal oxides and peroxides. The number of active sites of fillers was significantly higher than that of unloaded fillers, and the difference among the three was not significant. The CV of -0.1 ~ 0.6V showed that the ability of phenol oxidation by double-layer electric field was improved after the filler was loaded. The analysis of polarization curves shows that the manganese tin antimony type is superior to the unloaded type in oxygen evolution potential, and the load type is generally superior to the unloaded type in the exchange current density, and the manganese tin antimony type is the most significant. The measurement of AC impedance shows that the resistance of tin antimony type filler is the smallest, followed by manganese tin antimony type and manganese type in charge transfer resistance, which are all smaller than that of unloaded type. In the aspect of diffusion control, manganese, tin and antimony type have the most advantages, followed by tin antimony type and manganese type. Phenol wastewater treatment experiment was carried out in packed bed reactor with filler as particle electrode. The results of water treatment showed that the removal efficiency of COD and phenol was the best, followed by tin antimony type, manganese type and unloaded type. UV analysis showed that, After loading, the degradation of phenol intermediate products, such as benzoquinone, was improved, among which manganese filler was the best, followed by manganese tin antimony type and tin antimony type. Based on the analysis of related water treatment indexes and electrochemical characterization, it was suggested that manganese dioxide formed Mn Ox _ 1 in electrochemical water treatment, which promoted the selective oxidation of phenol and benzoquinone by fillers. It is inferred that tin dioxide type produces Sn O 2 (? OH),) which promotes the electrochemical combustion of benzene ring and other organic compounds. The analysis of energy consumption and current efficiency showed that Mn-Sn-Sb-type filler had obvious advantage, followed by Sn-Sb-type and Mn-type.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
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