光催化降解染料.doc

天津工业大学
毕业设计(论文)
题目:PTFE纤维金属配合物对偶氮染料的催化降解
姓名刘林云
学院纺织学院
专业轻化工程
指导教师董永春
职称教授
年月日
摘要
纤维与金属离子配合物可以作为非均相Fenton催化剂,其中改性聚丙烯腈和羊毛金属离子配合物已经得到发展并被证明对染料等有机污染物的氧化降解具有显著的催化作用。但是这两种纤维耐氧化性不高,而且其配合物作为催化剂使用时pH值适用范围较窄。因此,本文以化学稳定性极佳的聚四氟乙烯(PTFE)纤维作为基体,通过丙烯酸辐射对其进行接枝得到了改性PTFE纤维,然后将与Fe3+进行配位反应制备了改性PTFE纤维铁配合物,并考察了其作为非均相Fenton催化剂对常用偶氮染料活性红195降解反应的催化作用。重点研究了pH值对改性PTFE纤维铁配合物催化性能的影响,并对不同pH条件下活性红195降解过程的紫外可见光谱和COD去除率进行了考察。在分析pH影响改性PTFE铁配合物影响原因的基础上,考察了增加配合物Fe3+配合量、增强辐射光强度和引入Cu2+或Ce3+等助金属离子等方法对其pH适用性的改善作用。
研究结果显示,改性PTFE纤维铁配合物作为非均相Fenton反应催化剂能够明显催化活性红195的降解反应,然而升高溶液pH值会导致其催化活性有所降低。值得说明的是,增加配合物Fe3+配合量、增强辐射光和引入助金属离子Fe3+和Ce3+均能够显著促进染料的降解反应,并使改性PTFE纤维金属配合物在pH为中性和碱性条件下仍具有较高催化活性,从而对其pH适用性起到了明显的改善作用。此外,改性PTFE纤维铁配合物存在时,在各pH条件下活性红195的降解过程中染料分子中芳香环结构和共轭体系均遭到破坏,并随着反应的进行进一步发生矿化转化为无机物。
关键词:PTFE纤维;配合物;非均相Fenton催化剂;染料降解;pH适用性
ABSTRACT
The metallic plexes can be used as heterogeneous Fenton catalysts, and plexes between metal ions and modified PAN fibers or wool fibers have been effectively applied as catalysts for degradation anic pollutants. However, these fibers exhibted lower oxidation resistance, and their plexes as catalysts often showed a limited pH range. Therefore, polyfluortetraethylene (PTFE) fibers having excellent stability were modified with polyacrylic acid by Co irradiation, and then the resulting modified PTFE fibers were coordinated with Fe3+ to prepare the modified PTFE fiber plexes, and the catalytic activity of which as heterogeneous Fenton catalysts for the degradation of monly used azo dye, Reactive 195 was studied. The relationship between solution pH value and the cataltyic activity of the modified PTFE fiber plexes was studied, and the changes in UV-vis spectra and COD value during the degradation of Reactive 195 were also examined. In addition, some methods improving the pH limit such as increasing Fe content of plexes, enhancing light intensity and adding assisted metal ions are investigated.
The results indicated that modified PTFE fiber plexes could effectively catalyz