陶瓷-炭复合膜分离层的孔结构调制与性能表征
发布时间：2019-02-11 14:44
【摘要】：以煤全组分分离所得密中质组溶胶为前躯体,以酚醛树脂为添加剂,以平板圆形陶瓷为支撑体,采用由浸渍涂膜法并经炭化过程制备致密型复合膜分离层,再经活化调制分离层孔结构的两步法制备了陶瓷-炭复合膜,系统研究了成膜条件、炭化条件以及活化方式和活化条件对复合膜性能的影响,考察了复合膜截留牛血清蛋白的效果。对致密型复合膜的形成及分离层孔结构的调制机理进行了分析。结果表明:成膜过程中,随酚醛树脂添加量的增加,更易形成连续膜层;延长涂膜时间或者多次涂膜可使分离层的致密性增加,但涂膜时间过长不利于致密型复合膜分离层的形成。炭化过程中,升温速率影响热解气体析出,从而影响分离层孔隙率;中间恒温一段时间有利于炭化后膜层更连续无缺陷。终温温度或恒温时间的改变均会影响致密型复合膜分离层的形成。制备致密型分离层的陶瓷-炭复合膜较优条件为:酚醛树脂添加量为15%,涂膜4次,浸渍涂膜时间为25 min,升温速率3℃/min,中间恒温温度为380℃,中间恒温时间为90 min,炭化终温500℃,炭化最终恒温时间90 min。KOH活化法调制复合膜分离层孔结构的较优条件为:KOH浸泡时间为4 h,活化温度为750℃,活化时间为30 min。水蒸汽活化法调制复合膜孔结构的较优条件为:活化温度为850℃,活化时间为2 h,水流量为0.25 m L/min。KOH活化对牛血清蛋白的截留效果优于水蒸气活化。密中质组炭化过程中生成大量小分子,一部分以气体形式逸出体系,另一部分留在体系中作为溶剂形成液相,使体系维持良好的流动性,气体逸出液相体系形成孔隙结构。酚醛树脂在此温度下失重较少,只有少量气体逸出,热解残留物会滞留在体系中,填补小分子气体挥发留下的孔隙,从而有利于致密型复合膜分离层的形成。活化时酚醛树脂开始剧烈分解,生成大量气体,但此时密中质组已经固化,且结构致密,因而酚醛树脂分解产生的气体无法逸出,在分离层内部形成孔。KOH或水蒸气会和分离层上的碳反应,将这些内部孔隙打开,从而形成通透孔。
[Abstract]:A dense composite membrane separation layer was prepared by impregnation coating method and carbonization process using dense mesoplasm sol as precursor, phenolic resin as additive and flat circular ceramic as supporting body. The ceramic / carbon composite membrane was prepared by two-step method of activated modulation and separation layer pore structure. The effects of film forming conditions, carbonization conditions, activation mode and activation conditions on the properties of the composite membrane were systematically studied. The effect of the composite membrane on the retention of bovine serum protein (BSA) was investigated. The formation of compact composite membrane and the modulation mechanism of the pore structure of the separation layer were analyzed. The results show that the continuous film is more easily formed with the increase of the amount of phenolic resin in the process of film formation. The densification of the separation layer can be increased by prolonging the coating time or by coating several times, but too long coating time is not conducive to the formation of dense composite membrane separation layer. In the process of carbonization, the rate of heating affects the precipitation of pyrolytic gas, thus affects the porosity of the separation layer, and the intermediate constant temperature for a period of time is conducive to the film layer being more continuous without defects after carbonization. The change of final temperature or constant temperature time will affect the formation of dense composite membrane separation layer. The optimum conditions for the preparation of dense ceramic / carbon composite membrane are as follows: the amount of phenolic resin added is 15, the coating time is 4 times, the coating time is 25 min, the heating rate is 3 鈩，
本文编号：2419825
[Abstract]:A dense composite membrane separation layer was prepared by impregnation coating method and carbonization process using dense mesoplasm sol as precursor, phenolic resin as additive and flat circular ceramic as supporting body. The ceramic / carbon composite membrane was prepared by two-step method of activated modulation and separation layer pore structure. The effects of film forming conditions, carbonization conditions, activation mode and activation conditions on the properties of the composite membrane were systematically studied. The effect of the composite membrane on the retention of bovine serum protein (BSA) was investigated. The formation of compact composite membrane and the modulation mechanism of the pore structure of the separation layer were analyzed. The results show that the continuous film is more easily formed with the increase of the amount of phenolic resin in the process of film formation. The densification of the separation layer can be increased by prolonging the coating time or by coating several times, but too long coating time is not conducive to the formation of dense composite membrane separation layer. In the process of carbonization, the rate of heating affects the precipitation of pyrolytic gas, thus affects the porosity of the separation layer, and the intermediate constant temperature for a period of time is conducive to the film layer being more continuous without defects after carbonization. The change of final temperature or constant temperature time will affect the formation of dense composite membrane separation layer. The optimum conditions for the preparation of dense ceramic / carbon composite membrane are as follows: the amount of phenolic resin added is 15, the coating time is 4 times, the coating time is 25 min, the heating rate is 3 鈩，
本文编号：2419825
本文链接：https://www.wllwen.com/kejilunwen/huaxuehuagong/2419825.html
