【作者】 叶文彬；

【导师】 胡翔；

【作者基本信息】 北京化工大学 ， 环境科学与工程， 2010， 硕士

【摘要】 目前,PPCPs (Pharmaceutical and Personal Care Products)已被公认为是当今一类特殊的环境污染物,而常规的污水处理厂和自来水厂对这些污染物不能取得理想的去除率,这些污染物一部分残留在活性淤泥中,而大部分则直接通过二级处理系统,随出水被排放出去,因此需要寻找可行的技术去降解这些物质。本文中研究了双氯芬酸和三氯生的电化学降解过程。双氯芬酸是一种常用的非甾体抗炎药,由于其具有的难生物降解性,所以传统的城市污水处理设备并不能有效的处理双氯芬酸。三氯生是一种优异的杀菌添加剂,广泛用于卫生保健等领域。三氯生极难溶于水,并且当三氯生通过光降解转化为二恶英时,那么将对水中的生物造成巨大的危害。实验中研究了多壁碳纳米管(MWCNTs)电极对水相中PPCPs的电化学还原脱氯作用。考察了初始浓度、电解电压、pH值、电解质浓度和电解时间对PPCPs去除效率的影响。实验中,对比了石墨电极和碳纳米管电极对PPCPs的电化学降解过程,发现由于碳纳米管较大的表面积和优良的储氢能力,碳纳米管电极要优于石墨电极。实验数据还表明,对碳纳米管进行镀钯修饰能较大的提高电极的脱氯能力。实验结果表明,使用镀钯的碳纳米管电极进行电解时,当这两种PPCPs的浓度为50 mg·L-1,电压为30V,pH值为11,电解质Na2SO4浓度为1000 mg·L-1时,经过8h电解,PPCPs的去除效率达98%以上,脱氯率达80%以上。当这两种PPCPs的浓度为1 mg·L-1,电压为30V,pH值为7,电解质Na2SO4浓度为1000mg·L-1时,经过8h电解,PPCPs基本被完全去除。电极的SEM图谱显示,纯化后的MWCNTs拥有更小的粒径,因此拥有了更多的活化点。镀钯电极上钯的分布是非连续,这可能是由于碳纳米管独特的纳米结构和钯的化学沉积机理决定的。质谱的分析表明,碳纳米管上污染物降解的主要活性物质为氢气或H.。更多还原

【Abstract】 PPCPs (Pharmaceutical and Personal Care Products) has been recognized as a special kind of environmental pollutants nowadays, and the conventional sewage treatment plant and water plant could not be achieved ideal removal efficiency on these pollutants. Parts of these pollutants remained in the active mud, but most of these were directly through the secondary treatment system, and then were discharged out with the effluent. So, it is necessary to look for a technology which can degrade these substances effectively.In the aquatic environment, (i.e. internal surface waters), diclofenac is a an anti-inflammatory non-steroidal drugs and hard to biodegrade, so the traditional urban sewage treatment equipment can not remove diclofenac effectually. Triclosan is a kind of bactericides that has found applications in hygiene and health. Triclosan is poorly water-soluble and it is very toxic to water living organisms since it can be photodegraded to chlorodioxins.Electrocatalytic reductive dechlorination of diclofenac in aqueous solution was studied with a multiple-walled cardon nanotubes (MWCNTs) cathode and a platinum anode. The experiments were carried out to explore the effects of initial concentration, electrolytic voltage, pH, concentration of electrolyte and electrolysis time on dechlorination. In the experiment, the results of comparison between the MWCNTs electrode and the Graphite electrode show that MWCNTs electrode was more excellent, because it has large surface area and excellent hydrogen storage capacity. The results of the Pt/MWCNTs electrode show that when the concentration of PPCPs was 50 mg·L-1, the electrolytic voltage was 30V, the pH was 11, the concentration of Na2SO4 was 1000 mg·L-1, after 8h electrocatalytic reduction, the removal rate of diclofenac reached 98%, but the removal rate of chlorine reached 80%. when the concentration of PPCPs was 1 mg·L-1, the electrolytic voltage was 30V, the pH was 7, the concentration of Na2SO4 was 1000 mg·L-1, after 8h electrocatalytic reduction, PPCPs was completely removed.SEM images show:to unpurified MWCNTs, purified MWCNTs have smaller grain diameter and more actives sites. The distribution of palladium on the electrode is discontinuous, due to the characteristic structure of MWCNTs and the mechanism of chemical deposition. MS show that hydrogen or H·is the main active substance in the degradation of pollutants on the carbon nanotubes.更多还原