微流控反应器中苯酚电催化氧化研究

发布时间：2018-05-03 13:54

本文选题：阳极氧化 + 微流控反应器　；参考：《天津大学》2015年硕士论文

【摘要】：酚类物质在目前的工业生产中应用十分广泛,是典型的有毒、生物难降解有机物,这类物质的排放对环境及生物都有严重的危害。在含酚废水的处理技术中电化学催化氧化技术具有良好的发展前景。针对电催化技术中反应器的开发,本文研究了微流控反应器中苯酚的直接阳极氧化过程,分析了此种微流控反应器对苯酚电催化氧化降解的促进作用。首先,采用高温氧化法和电沉积法制备得到六种不同的活性阳极,分别对各电极进行电化学特性和常规反应器中的降解效果分析。使用循环伏安扫描曲线和线性伏安曲线对各电极的过氧电位及苯酚氧化峰进行对比,以优选出过氧电位高、苯酚氧化峰电势低的阳极。将对比结论与苯酚降解效果结合分析,最终筛选出电化学性能良好的Ti/SnO_2-Sb_2O_5及Ti/Sn-Sb/PbO_2电极,二者的析氧电位均为2.5 V,7小时后降解终点的苯酚去除率也可分别达到80%及90%。进一步将筛选后电极分别安置在微通道电解槽内,并对各操作参数如ΦV、h、i进行了考察。研究结果表明,微通道电解槽的特别构型可以强化有机物在阳极表面的传质,增大了反应速率常数,使降解过程可以在较短的时间内达到相同的降解效果。在同样达到90%苯酚去除率的情况下,微流控反应器可以将降解时间由常规反应器中的6~7小时缩短到2~3小时,提高了电流效率,有效控制能耗。对苯酚的第一步氧化过程进行动力学分析,提出零级和拟一级反应假设对实验数据进行回归,回归结果显示不同阳极表面苯酚在微通道电解槽内的动力学分析结果有所不同。当使用Ti/SnO_2-Sb_2O_5/PbO_2时回归偏差较大,说明此时苯酚的降解过程不是由传质及电子转移控制,推测该过程为反应控制。在Ti/SnO_2-Sb_2O_5阳极环境下的良好回归结果说明微流控反应器中Ti/SnO_2-Sb_2O_5阳极表面的苯酚电催化氧化过程主要受传质控制,并与电子转移进行的次级控制协同作用。
[Abstract]:Phenols are widely used in industrial production, which is a typical toxic and biodegradable organic matter. Electrochemical catalytic oxidation (ECO) technology has a good prospect in the treatment of phenol-containing wastewater. The direct anodizing process of phenol in microfluidic reactor was studied in this paper, and the effect of this microfluidic reactor on the electrocatalytic degradation of phenol was analyzed. Firstly, six kinds of active anode were prepared by high temperature oxidation method and electrodeposition method. The electrochemical characteristics of each electrode and the degradation effect in conventional reactor were analyzed. The peroxidation potential and phenol oxidation peak of each electrode were compared by cyclic voltammetry and linear voltammetry to select the anode with high peroxidation potential and low potential of phenol oxidation peak. Finally, the Ti/SnO_2-Sb_2O_5 and Ti/Sn-Sb/PbO_2 electrodes with good electrochemical performance were selected by combining the results with phenol degradation. The removal rates of phenol at the end point of degradation were 80% and 90%, respectively, when the oxygen evolution potentials of the two electrodes were both 2.5 V ~ (2) V ~ (-1) for 7 hours. Further, the selected electrodes were placed in the microchannel electrolysis cell respectively, and the operation parameters such as 桅 VHN I were investigated. The results show that the special configuration of the microchannel electrolysis cell can enhance the mass transfer of organic matter on the anode surface, increase the reaction rate constant, and make the degradation process achieve the same degradation effect in a relatively short time. When the removal rate of phenol is 90%, the degradation time of microfluidic reactor can be shortened from 6 ~ 7 hours in the conventional reactor to 2 ~ 3 hours, which improves the current efficiency and effectively controls the energy consumption. The kinetic analysis of the first step oxidation of phenol was carried out, and the zero-order and quasi-first-order reaction assumptions were proposed to regression the experimental data. The regression results showed that the kinetic analysis results of phenol on different anodic surfaces in the microchannel electrolyzer were different. When Ti/SnO_2-Sb_2O_5/PbO_2 was used, the regression deviation was large, which indicated that the degradation process of phenol was not controlled by mass transfer and electron transfer, and the process was supposed to be controlled by reaction. The good regression results under Ti/SnO_2-Sb_2O_5 anodic environment indicate that the electrocatalytic oxidation of phenol on the surface of Ti/SnO_2-Sb_2O_5 anode is mainly controlled by mass transfer and the secondary control of electron transfer is synergistic.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;O646;O643.3

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