基于静电纺丝技术制备ZnO-碳复合纳米纤维及电容去离子研究

发布时间：2018-04-20 09:01

本文选题：静电纺丝 + 碳纳米纤维　；参考：《东华大学》2015年硕士论文

【摘要】：淡水是人类及一切生物赖以生存的必不可少的重要物质，，是工农业生产、经济发展和环境改善不可替代的极为宝贵的自然资源。淡水资源短缺是目前正面临的全球问题。海水或者苦咸水淡化对解决这一重大问题来说具有重要意义。因此开发高效的脱盐淡化技术至关重要。电容器脱盐，又称电容去离子（CDI）是一种新型的电化学水处理技术。与现有的反渗透和电渗析等膜技术相比，CDI技术操作成本低，无二次污染，是目前比较受广大研究者关注的一种新型除盐技术。电极材料是制约CDI技术发展的关键。碳纳米纤维是一种出色的电极材料。静电纺丝技术是一种非常简单的制备纤维材料的方法。聚丙烯腈（PAN）具有良好的可纺性和相对较高的碳产量，而且经过预氧化、碳化后可以直接获得碳纳米纤维（CNF），被广泛选择用于制造CNF的前驱体。然而，以纯PAN作前驱体静电纺丝制备的碳纳米纤维电极结构性能不佳，离子吸附能力较差。本文选用氯化锌（ZnCl2）、醋酸锌（Zn(Ac)2）为添加剂，通过静电纺丝技术制备纳米纤维，在后续预氧化、碳化处理过程中添加剂分解为ZnO负载在纤维内部，得到ZnO分布均匀的ZnO-碳复合纳米纤维，并作为电极用于电容脱盐。利用能量色散谱、X射线光电子能谱、透射电镜、拉曼光谱、热重分析、场发射扫描电镜、接触角测量仪和电化学技术研究了不同添加剂对纤维元素成分、结构性能的影响以及不同配比对电容脱盐的影响。主要研究成果如下：通过在纺丝前驱液中加入添加剂ZnCl2静电纺制备ZnCl2/PAN复合纳米纤维原丝，由于ZnCl2在热处理过程中高温分解，经预氧化、碳化和水洗，得到ZnO-CNF(ZnCl2)复合纳米纤维。研究表明其亲水性增加，石墨化程度提高，ZnO分布均匀。以ZnO-CNF(ZnCl2)为电极材料组装电容器，脱盐量大大提高，且脱盐量与ZnO含量成正比关系，ZnO含量越高，其脱盐效果越好。当ZnCl2添加比例为2wt%时，EDS测得ZnO-CNF(ZnCl2)中负载的ZnO含量最高，其对应的脱盐量较大，最大脱盐量为8.35mg/g，电流效率为69.89%。通过在纺丝前驱液中加入添加剂Zn(Ac)2静电纺制备Zn(Ac)2/PAN复合纳米纤维原丝，所得纤维均匀性更好，经预氧化、碳化和水洗，得到ZnO分布均匀的ZnO-CNF(Zn(Ac)2)复合纳米纤维。SEM及TEM表征表明纤维表面ZnO分布均匀。以ZnO-CNF(Zn(Ac)2)为电极材料组装电容器用电容脱盐，脱盐量与ZnO含量成正比关系，ZnO含量越高，其脱盐效果越好。当Zn(Ac)2添加比例为3wt%时，ZnO-CNF(Zn(Ac)2)中负载的ZnO含量最高。以此电极组装电容器进行电容脱盐，最大脱盐量为11.24mg/g，电流效率为58.74%。综上所述，以ZnCl2和Zn(Ac)2为添加剂制得的ZnO-碳复合纳米纤维皆可应用于电容脱盐，且脱盐性能良好，有望应用于实际脱盐。对比两种材料发现，以Zn(Ac)2为添加剂制得的ZnO-碳复合纳米纤维电极的脱盐量更高。
[Abstract]:Fresh water is an indispensable and important material for human beings and all living things. It is an irreplaceable and valuable natural resource for industrial and agricultural production, economic development and environmental improvement. The shortage of fresh water is a global problem. Desalination of seawater or brackish water is of great significance in solving this major problem. Therefore, it is very important to develop efficient desalination and desalination technology. Capacitor desalination, also known as capacitor deionization (CDI), is a new electrochemical water treatment technology. Compared with the existing membrane technologies such as reverse osmosis and electrodialysis, the CDI technology has low operating cost and no secondary pollution, so it is a new desalination technology which has been paid more attention to by many researchers at present. Electrode material is the key to the development of CDI technology. Carbon nanofibers are an excellent electrode material. Electrostatic spinning is a very simple method for preparing fiber materials. Polyacrylonitrile (pan) has good spinnability and relatively high carbon yield, and after carbonization, carbon nanofibers can be directly obtained. However, the carbon nanofiber electrode prepared by electrospinning with pure PAN as precursor has poor structure performance and poor ion adsorption ability. In this paper, zinc chloride (ZnCl _ 2) and zinc acetate (Zn _ 2O _ 3) were used as additives to prepare nanofibers by electrostatic spinning. The additives were decomposed into ZnO loaded fibers during subsequent preoxidation and carbonization. ZnO- carbon nanofibers with uniform ZnO distribution were obtained and used as electrodes for capacitor desalination. X-ray photoelectron spectroscopy, transmission electron microscope, Raman spectrum, thermogravimetric analysis, field emission scanning electron microscope, contact angle measuring instrument and electrochemical technique were used to study the composition of fiber elements with different additives. The influence of structure performance and different ratio on capacitance desalting. The main findings are as follows: The ZnCl2/PAN composite nanofiber precursor was prepared by adding the additive ZnCl2 electrospun into the spinning precursor solution. Because the ZnCl2 was decomposed at high temperature during the heat treatment, the composite nanofibers were prepared by pre-oxidation, carbonization and water washing. The results show that the increase of hydrophilicity and the increase of graphitization degree lead to uniform distribution of ZnO. Using ZnO-CNFU ZnCl2) as the electrode material, the desalination amount is greatly increased, and the higher the ZnO content is, the better the desalting effect is. When the proportion of ZnCl2 added is 2 wt%, the loading ZnO content is the highest, the corresponding desalting amount is larger, the maximum desalting amount is 8.35 mg / g, and the current efficiency is 69.89%. The Zn(Ac)2/PAN composite nanofiber precursor was prepared by adding the additive Zn(Ac)2 electrospun into the spinning precursor solution. The obtained fiber has better homogeneity and is preoxidized, carbonized and washed. The ZnO distribution of ZnO-CNF / ZnAZAK _ (2)) composite nanofibers was obtained. The results showed that the ZnO distribution on the surface of the fibers was uniform. The capacitance desalination of capacitors assembled with ZnO-CNF Zn-Zn-AZO _ 2) was carried out. The higher the content of ZnO was, the better the desalination effect of the capacitors was when the amount of desalination was in direct proportion to the content of ZnO-CNF _ (2). When the ratio of Zn(Ac)2 was 3 wt%, the content of ZnO was the highest. The capacitor was desalted with this electrode, the maximum desalting amount was 11.24 mg / g, and the current efficiency was 58.74%. In conclusion, ZnO-carbon nanofibers prepared with ZnCl2 and Zn(Ac)2 as additives can be used in capacitive desalination, and the desalination performance is good, which is expected to be used in practical desalination. Compared with the two materials, it was found that the amount of desalination of ZnO-carbon composite nanofiber electrode prepared with Zn(Ac)2 as additive was higher.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ343;TB383.1

【参考文献】