【作者】 王晓东；

【导师】 顾平；

【作者基本信息】 天津大学 ， 环境工程， 2008， 博士

【摘要】 半导体光催化剂在光催化降解氯酚类等难生化处理有机物方面具有能耗低,反应条件温和,操作简便,可减少二次污染等突出特点,因此备受环境科学工作者的关注。半导体粒子吸收能量大于其带隙能的光量子时,一个电子从价带被激发到导带,结果这个电子对吸附在颗粒表面的分子起化学还原作用,同时价带上的空穴起化学氧化的作用。纳米ZnO微球具有很高的活性,能够把有机物降解为CO2、H2O和一些无机酸,而且ZnO具有安全、廉价、无污染等优点,是最有发展前途的绿色环保型催化剂之一。本文采用醇解方法制备纳米晶体ZnO微球,探讨了升温速率对醇解反应发生温度的影响。考察了种子液用量以及醇解时间对纳米级的ZnO微球的形貌影响。膜生物反应器(MBR)技术应用于饮用水的处理尚是一项较新的技术,90年代中期首次在法国出现应用实例。目前应用MBR对微污染水源水中微量2,4,6–TCP的去除尚未见报道。本试验设计采用MBR作为主体工艺来处理微污染地表水,向反应器内投加PAC以强化处理效果,在关注MBR对微污染地表水中有机物总量去除的同时,还将水中同时存在的微量氯酚类化合物2,4,6–TCP作为目标污染物之一。本试验的目的是使MBR及其组合工艺(MBR+PAC)能够稳定运行,能够实现对微污染水中有机物总量去除的同时,保证对其中的微量人工合成有机物高效的去除,使出水水质能够达到《生活饮用水卫生标准》(GB5749–2006)的要求,为实现MBR的工程化提供技术支持。研究中考察了微量水平下的2,4,6–TCP在膜生物反应器中的降解机理,实验中面临的难题之一就是2,4,6-TCP及其各种降解中间产物的检测问题。SPME是一种新型的微量样品富集技术。目前国内对于SPME–HPLC联用技术的研究还刚刚起步,应用性文献不多。论文综述了近年来SPME技术的发展状况,详细介绍了SPME-HPLC联用技术的原理、仪器及其在各环境领域的应用。通过对SPME和HPLC联用技术的研究,优化了SPME和HPLC联用的实验条件,初步建立了SPME–HPLC分析环境水样中痕量酚类化合物的方法。更多还原

【Abstract】 Semiconductor photo-catalysts have attracted considerable attention in the field of environmental science due to their many significant advantages such as low consumption, mild reaction condition, simple operation and decrease of secondary pollution in photo-degradation of refractory organic pollutants including chlorophenol. When the semiconductor particle is illuminated by light having higher energy than its band gap energy, an electron is excited from the conduction band to valence band to reduce the molecule absorbed on the surface of the particle and the hole in valence band can act as an oxidant. ZnO is one of the most promising green catalysts due to its higher photo-degradation ability in decomposing of the organic pollutants into CO2, H2O and some mineral acid as well as its many advantages (i.e., safety, non-toxic nature, low cost and no pollution). In this thesis, ZnO nanoparticles were firstly prepared through the thermal alcoholysis reaction of zinc acetate in diethylene glycol (DEG). The effect of heating rate on the alcoholysis temperature was explored. The influences of seed solution amount added and reaction time on the surface morphologies of zinc oxide microspheres were also discussed.MBR process used in the treatment of drinking water is still a relatively new technology, which was first developed in the mid-1990s in France. Using MBR for trace 2,4,6-TCP removal in micro-polluted water sources has not been reported up to present. In this thesis, the experimental design used MBR as the main technology to address micro-polluted surface water to the reactor, adding PAC to strengthen the effect in the mean time. The purpose of this test is not only to remove the organic pollutants as a whole, but also to achieve effective removal of the trace 2,4,6-TCP compound at the same time during the stable operation of MBR. As a result, the treated water from MBR or MBR-PAC process could meet the requirements of Standards for drinking water quality (GB5749-2006).SPME is a new kind of micro-sample enrichment technology. In this thesis, the development of the technology of SPME coupled with HPLC, including the principle, the apparatus and its various applications, in the field of environment in recent years were reviewed. Through the preliminary study, the analysis methods under the optimized experimental conditions of SPME-HPLC were established for fast determination of trace phenolic compounds in micro-polluted lake water.更多还原