介孔炭修饰复合炭膜的研究

发布时间：2018-05-26 09:03

  本文选题：软模板法 + 酚醛树脂　； 参考：《大连理工大学》2016年硕士论文

【摘要】：膜分离技术作为一种新型气体分离技术,因其高性能、低成本、操作简单等优点而备受瞩目。炭膜是一种由含碳物质经高温热解炭化而成的新型炭基膜材料,具有耐高温、抗腐蚀、耐酸碱、生物相容性好、孔径可调且气体分离性能优异等特点,因此应用前景十分广阔。均质炭膜因质脆、强度低无实用价值。为了实现其实际应用,通常制备成具有一定强度的复合炭膜,即在具有一定机械强度的支撑体上复合一层炭膜前驱体,经高温热解形成复合炭膜。然而,作为支撑体的多孔材料通常孔径较大,表面存在针眼或缺陷,容易转移到分离层表面,影响复合炭膜的分离性能。所以,对支撑体表面进行修饰是制备高性能复合炭膜的关键。介孔炭材料是一种具有较高比表面积,均一孔径结构的功能型材料,是修饰炭膜支撑体缺陷的理想材料。本论文利用软模板法,分别采用酸、碱催化剂合成介观相酚醛树脂,修饰支撑体,并在此基础上涂覆分离层,制备复合炭膜。主要探讨了介观相酚醛树脂的合成反应温度、时间以及炭化工艺等对介孔炭结构的影响。通过XRD、N2吸附、TEM及气体渗透装置等手段,对所制备的介孔炭的孔结构特性、微观形貌及气体渗透分离性能进行表征。得到如下结果：1、在酸性催化剂下,当合成时间为3 h,老化时间为72h,炭化温度为6000C,恒温时间为2h,制备得到的介孔炭为蠕虫状孔结构,其孔容和比表面积分别为0.613cm3/g和685.75m2/g,平均孔径为2.2 nm。用其制备介孔炭膜,其氧气通量为77390 barrer,氧氮选择性为0.99。在碱性催化剂参与下,当反应温度为70℃,合成时间为1 h,炭化温度为600 ℃,恒温时间为4 h,制备得到的介孔炭有序度良好,其平均孔径为4.0 nm;制备的介孔炭膜,其氧气通量为24850 barrer,氧氮选择性为1.11。2、采用介观相酚醛树脂聚合物修饰炭膜支撑体,得到的支撑体孔径均一,表面更加平整,渗透通量维持在2000GPU左右。3、采用旋涂法在修饰后的支撑体上涂覆分离层,制备得到了具有一定的气体分离性能的复合炭膜。发现介观相酚醛树脂的合成方法对所制备的复合炭膜的气体分离性能有一定的影响。以酸性催化剂合成的介观相酚醛树脂修饰的支撑体制备的复合炭膜其氧气通量为1615 GPU,氧氮选择性为2.07。以碱酸性催化剂合成的介观相酚醛树脂修饰的支撑体制备的复合炭膜其氧气通量为1193 GPU,氧氮选择性为1.53。
[Abstract]:As a new gas separation technology, membrane separation technology has attracted much attention because of its high performance, low cost and simple operation. Carbon film is a kind of new carbon base membrane material which is prepared by pyrolysis and carbonization of carbonaceous material at high temperature. It has the characteristics of high temperature resistance, corrosion resistance, acid and alkali resistance, good biocompatibility, adjustable pore size and excellent gas separation performance. Therefore, the application prospect is very broad. Homogeneous carbon film has no practical value because of its brittleness and low strength. In order to realize its practical application, the composite carbon film with a certain strength is usually prepared, that is, the composite carbon film is formed by pyrolysis at high temperature on the support with a certain mechanical strength. However, porous materials, which are usually used as supports, usually have large pore size and have pinhole or defects on the surface, which can easily be transferred to the surface of the separation layer and affect the separation performance of the composite carbon membrane. Therefore, the surface modification of the support is the key to the preparation of high performance composite carbon film. Mesoporous carbon is a functional material with high specific surface area and homogeneous pore structure. It is an ideal material for modifying the defects of carbon membrane support. In this paper, mesoscopic phenolic resin was synthesized with acid and alkali catalyst by soft template method, and modified with support, and then coated with separation layer to prepare composite carbon membrane. The effects of reaction temperature, reaction time and carbonization process on the structure of mesoporous carbon were investigated. The pore structure, micromorphology and gas permeation performance of the prepared mesoporous carbon were characterized by means of XRDN _ 2 adsorption TEM and gas permeation apparatus. The results are as follows: 1. Under acidic catalyst, the mesoporous carbon is worm-like structure when the synthesis time is 3 h, the aging time is 72 h, the carbonization temperature is 6 000 C, and the constant temperature time is 2 h. The pore volume and specific surface area are 0.613cm3/g and 685.75m2 / g, respectively. The average pore size is 2.2 nm. The oxygen flux and oxygen nitrogen selectivity of mesoporous carbon membrane were 77390 barrer and 0.99, respectively. When the reaction temperature was 70 鈩，

本文编号：1936647