木棉基活性炭纤维的可见光光催化的性能研究

发布时间：2018-01-06 00:04

本文关键词：木棉基活性炭纤维的可见光光催化的性能研究　出处：《武汉纺织大学》2017年硕士论文　论文类型：学位论文

更多相关文章： 木棉基ACF 光催化 共掺杂 CNT

【摘要】：当今社会快速发展,纺织领域中印染排放的废水污染、汽车排放的尾气污染等日益严重。各种各样的治理方法被开发应用,而活性炭纤维(ACF)因比表面积大、吸附脱附快、吸附量大、孔径适中等优点,是近几年来应用最广泛、最新型的功能材料。本课题以木棉纤维为基体,采用化学活化的方法,制备Ag掺杂TiO_2木棉基ACF、Mn掺杂TiO_2木棉基ACF和CNT负载木棉基ACF三种活性炭纤维。采用FTIR、RAMAN、SEM、XRD、元素分析等对木棉基ACF的微观结构和表面形态等进行表征,以亚甲基蓝溶液模拟染色废水,研究了木棉基ACF的吸附动力学,探究Ag、Mn对TiO_2木棉基ACF的可见光光催化降解性能的影响,比较不同掺杂量对木棉基ACF吸附性能的影响,并获得最佳掺杂比。首先,采用凝胶-溶胶法制备7种不同Ag掺杂量的TiO_2木棉基ACF,以及木棉基ACF和TiO_2木棉基活性炭,结果表明:活性炭纤维的物相结构具有相似性,均存在石墨成分。Ag掺杂没有与木棉基ACF发生化学键合,属物理过程。掺杂Ag对活性炭纤维的可见光吸附性能有一定的提高。当Ag掺杂含量为0.5%,活性炭纤维吸附性能最佳,吸光度最小。用凝胶-溶胶法制备6种不同Mn掺杂量的TiO_2木棉基ACF。结果证明,Mn掺杂属物理过程,不与ACF发生化学键合。掺杂可改善TiO_2的团聚以及龟裂,提升TiO_2木棉基ACF的可见光催化降解能力。当掺杂量n(Mn):n(Ti)=1:150时,制备的ACF的可见光吸附模拟废水的性能最佳。Mn掺杂ACF具有较高重复使用率,经5次吸附处理,吸附率仅下降了36%,重复使用仍然保持较高的吸附与光催化降解率。最后选用孔径为10~20nm的CNT浸渍负载,制备6种不同CNT负载量的木棉基ACF。结果发现:CNT不与木棉基ACF发生化学反应,仅物理附着;随CNT负载量的增加,木棉基ACF的吸附性能先增大后减小。当CNT负载量为12%时,吸附效果达到最好,制备的ACF炭化程度高且在可见光下具有良好的吸附活性。制备的三种木棉基ACF对亚甲基蓝的吸附均适合准二级动力学方程模拟,属单分子吸附。对于TiO_2木棉基ACF,当掺杂量较小时,Ag或Mn可以在TiO_2的导带和价带之间产生附加能级,降低其禁带宽度,提高了TiO_2的光催化活性,扩宽其光响应范围。当掺杂量较大时,过量的Ag或Mn在TiO_2表面附着,成为电子和空穴的复合中心,反而降低TiO_2的光催化活性。
[Abstract]:Nowadays, with the rapid development of society, the pollution of printing and dyeing wastewater and the exhaust gas of automobile are becoming more and more serious in the textile field. A variety of treatment methods have been developed and applied. Activated carbon fiber (ACFC) is the most widely used and new functional material in recent years because of its large surface area, fast adsorption and desorption, large amount of adsorption and moderate pore size, etc. In this paper, kapok fiber is used as the matrix. Three kinds of Ag-doped TiO_2 kapok based ACF and CNT supported kapok based ACF activated carbon fibers were prepared by chemical activation method. FTIR was used. The microstructure and surface morphology of kapok based ACF were characterized by elemental analysis, and methylene blue solution was used to simulate dyeing wastewater. The adsorption kinetics of kapok based ACF was studied, and the effect of Agnon mn on the visible photocatalytic degradation of TiO_2 kapok based ACF was investigated. The effects of different doping contents on the adsorption properties of kapok based ACF were compared, and the optimum doping ratio was obtained. Firstly, seven kinds of Ag-doped TiO_2 kapok based ACF were prepared by gel sol method. And kapok based ACF and TiO_2 kapok based activated carbon. The results show that the phase structure of the activated carbon fiber is similar, and there is no chemical bond between the carbon component. Ag doped and the kapok based ACF. It is a physical process. The absorption property of activated carbon fiber can be improved by doping Ag. When Ag doping content is 0.5, the adsorption property of activated carbon fiber is the best. The absorbance is minimum. Six kinds of TiO_2 kapok cotton based CFCs with different mn doping amount were prepared by gel-sol method. The results show that mn doping is a physical process. No chemical bonding with ACF occurs. Doping can improve the agglomeration and cracking of TiO_2. The visible light catalytic degradation ability of TiO_2 kapok based ACF was improved when the doping amount was 1: 150. The performance of the simulated wastewater by visible light adsorption of the prepared ACF is the best. Mn-doped ACF has a high reuse rate. After five times of adsorption treatment, the adsorption rate is only reduced by 36%. The repeated use still keeps high adsorption and photocatalytic degradation rate. Finally, the CNT impregnation loading with pore diameter of 10 ~ 20 nm is selected. Six kinds of CNT loaded kapok ACFs were prepared. The results showed that CNT did not react with kapok ACF, but only physically adhered to them. With the increase of CNT loading, the adsorption performance of kapok based ACF firstly increased and then decreased. When the amount of CNT loading was 12%, the adsorption effect was the best. The prepared ACF has high carbonization degree and good adsorption activity under visible light. The adsorption of methylene blue by three kinds of kapok based ACF is suitable for quasi-second-order kinetic equation simulation. For TiO_2, Ag or mn can produce additional energy levels between the conduction band and valence band of TiO_2, and decrease the band gap. The photocatalytic activity of TiO_2 is improved and the range of photoresponse is broadened. When the doping amount is high, the excess Ag or mn is attached to the surface of TiO_2 and becomes the composite center of electron and hole. On the contrary, the photocatalytic activity of TiO_2 was decreased.
【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424;TB34

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