【摘要】：以煤全組分分離所得密中質(zhì)組溶膠為前軀體,以酚醛樹脂為添加劑,以平板圓形陶瓷為支撐體,采用由浸漬涂膜法并經(jīng)炭化過程制備致密型復(fù)合膜分離層,再經(jīng)活化調(diào)制分離層孔結(jié)構(gòu)的兩步法制備了陶瓷-炭復(fù)合膜,系統(tǒng)研究了成膜條件、炭化條件以及活化方式和活化條件對復(fù)合膜性能的影響,考察了復(fù)合膜截留牛血清蛋白的效果。對致密型復(fù)合膜的形成及分離層孔結(jié)構(gòu)的調(diào)制機(jī)理進(jìn)行了分析。結(jié)果表明:成膜過程中,隨酚醛樹脂添加量的增加,更易形成連續(xù)膜層;延長涂膜時(shí)間或者多次涂膜可使分離層的致密性增加,但涂膜時(shí)間過長不利于致密型復(fù)合膜分離層的形成。炭化過程中,升溫速率影響熱解氣體析出,從而影響分離層孔隙率;中間恒溫一段時(shí)間有利于炭化后膜層更連續(xù)無缺陷。終溫溫度或恒溫時(shí)間的改變均會影響致密型復(fù)合膜分離層的形成。制備致密型分離層的陶瓷-炭復(fù)合膜較優(yōu)條件為:酚醛樹脂添加量為15%,涂膜4次,浸漬涂膜時(shí)間為25 min,升溫速率3℃/min,中間恒溫溫度為380℃,中間恒溫時(shí)間為90 min,炭化終溫500℃,炭化最終恒溫時(shí)間90 min。KOH活化法調(diào)制復(fù)合膜分離層孔結(jié)構(gòu)的較優(yōu)條件為:KOH浸泡時(shí)間為4 h,活化溫度為750℃,活化時(shí)間為30 min。水蒸汽活化法調(diào)制復(fù)合膜孔結(jié)構(gòu)的較優(yōu)條件為:活化溫度為850℃,活化時(shí)間為2 h,水流量為0.25 m L/min。KOH活化對牛血清蛋白的截留效果優(yōu)于水蒸氣活化。密中質(zhì)組炭化過程中生成大量小分子,一部分以氣體形式逸出體系,另一部分留在體系中作為溶劑形成液相,使體系維持良好的流動性,氣體逸出液相體系形成孔隙結(jié)構(gòu)。酚醛樹脂在此溫度下失重較少,只有少量氣體逸出,熱解殘留物會滯留在體系中,填補(bǔ)小分子氣體揮發(fā)留下的孔隙,從而有利于致密型復(fù)合膜分離層的形成。活化時(shí)酚醛樹脂開始劇烈分解,生成大量氣體,但此時(shí)密中質(zhì)組已經(jīng)固化,且結(jié)構(gòu)致密,因而酚醛樹脂分解產(chǎn)生的氣體無法逸出,在分離層內(nèi)部形成孔。KOH或水蒸氣會和分離層上的碳反應(yīng),將這些內(nèi)部孔隙打開,從而形成通透孔。
[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，

本文編號：2419825