【作者】 于婷；

【导师】 张翼；

【作者基本信息】 大庆石油学院 ， 化学工艺， 2009， 硕士

【摘要】 主要研究稀土掺杂Ti/TiO₂电极的制备及其性能,并以油田废水为目标有机物,对其降解工艺进行了优化。本论文对影响稀土掺杂Ti/TiO₂电极性能的主要因素:热处理温度、热处理时间和稀土的掺杂量等内容进行了较详细的研究。通过所制备电极对油田废水处理效果的评价,确定了三种电极的制备工艺,分别为:Ce掺杂Ti/TiO₂电极,热处理温度为450℃,热处理时间为1.5h,Ce的掺杂量质量比为100:1.5时为佳;Nd掺杂Ti/TiO₂电极,热处理温度为540℃,热处理时间为1h,Nd的掺杂量质量比为100:1.0时,电极性能最佳;混合稀土（La、Ce、Nd及微量Fe）掺杂Ti/TiO₂电极,热处理温度为500℃,热处理时间为1.5h,混合稀土的掺杂量质量比以100:1.5时为佳。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、电子能谱（EDX）等检测分析方法对不同稀土掺杂Ti/TiO₂电极的涂层晶体结构、电极表面形貌、电极表面涂层的元素组成进行了表征及分析。结果表明,掺杂稀土后电极的表面凹凸感变小,表面更为平滑、致密,几乎没有裂缝,均匀一致的高密度小碎片结构提高了导电性和催化性能。掺杂后TiO₂电极的晶体结构主要为锐钛矿型。稀土的掺入使得晶相所对应的衍射峰强度变弱且峰形宽化,这说明适量稀土的掺杂使涂层表面TiO₂晶粒细化了,稀土元素较好地分散在TiO₂晶格内部,增加TiO₂吸引质子或电子的能力,提高TiO₂电极的导电性和电催化活性。本论文对油田废水的降解工艺进行了优化。得出最佳降解工艺参数为:混合稀土（La、Ce、Nd及微量Fe）掺杂Ti/TiO₂电极为阳极,Ti电极为阴极,电极浸入面积2cm2,电极间距1cm,以NaCl为电解质,浓度为0.2mol·L-1,pH=3～4,电解电压16.5V,电解时间60min。在最佳工艺条件下对油田废水CODcr的去除率平均达到87.3%。紫外光谱分析表明,降解过程中污染物直接矿化为CO2和H2O,无其它中间产物生成。更多还原

【Abstract】 This paper focused on the preparation of rare earth-doped Ti/TiO₂ electrode and investigation on its characteristics. Taking oil-field wastewater as model substrate, the optimization of degradation processes was studied.The temperature of thermal treatment and the time of thermal treatment and the doping amount of rare earth were studied in detail, which were the main influence factors on the characteristics of electrodes. On the basis of the degradation of oil-field wastewater, the preparation conditions of the three kinds of electrodes were determined. The optimal temperature and time and the proportion of doping amount of Ce-doped Ti/TiO₂ electrode were 450℃, 1.5h and 100:1.5, respectively. The best temperature and time and the proportion of doping amount of Nd-doped Ti/TiO₂ electrode were 540℃, 1h and 100:1.0, respectively. The best temperature and time and the proportion of doping amount of La/Ce/Nd mischmetal-doped Ti/TiO₂ electrode were 500℃, 1.5h and 100:1.5, respectively.The micrograph and structure of the electrode surface and the element composition of surface layers were analyzed by SEM, EDX and XRD. The electrode surface became more smooth, more dense and almost no cracks after rare earth doping. The uniform of the high-density structure of the small debris may have a larger surface area and surface roughness, which was in favor of catalytic reactions. The crystal structure of TiO₂ electrode was anatase. Experimental results showed that doping of rare earth at a proper proportion was in favor of grain refining, it could increase the specific surface area of the coating and help to enhance the electrical conductivity and electro-catalytic ability of electrodes. Rare earth elements might be highly dispersed in TiO₂ internal lattice to increase the ability of attracting electrons or protons, and then to improve the catalytic activity of TiO₂ electrode.The degradation processes of oil-field wastewater were studied. The result indicated that the best effect was obtained when La/Ce/Nd mischmetal-doped Ti/TiO₂ electrode was anode. When electrode buried area and interval were 2cm2 and 1cm, electrolytic concentration of NaCl was 0.2mol·L-1, pH was 3-4, the electrolysis voltage was 16.5V and the electrolysis time was 60min, the best treatment process was obtained. The removal efficiency of CODcr were 87.3%. Under the best treatment process, contaminant was directly mineralized to CO2 and H2O without other intermediate substances.更多还原