【作者】 秦志宏； 宋兆兰； 陈冬梅； 曹丹； 李苗苗；

【Author】 QIN Zhihong;SONG Zhaolan;CHEN Dongmei;CAO Dan;LI Miaomiao;China University of Mining & Technology;

【机构】 中国矿业大学；

【摘要】 以煤萃取反萃取法分离所得密中质组分溶胶为涂覆液,经成膜和炭化,成功制备了煤基陶瓷-炭复合膜。并对复合炭膜的孔隙率、纯水渗透率和Fe(OH)3胶体和BSA溶液截留率进行了表征,系统研究了成膜条件和炭化条件对复合炭膜分离层性能的影响;通过红外分析、热重分析、扫描电子显微镜和孔径分析等考察了在复合炭膜分离层的演化过程中密中质组分的结构特征、热解行为和其表面微观结构及孔径分布。结果表明:影响复合炭膜截留率和孔隙率的最主要因素是升温速率和炭化终温,而涂膜次数则对渗透率有重要影响,通过调控成膜和炭化条件可制备性能不同的复合炭膜分离层。密中质组分溶胶涂层经干燥和炭化形成密中质组分炭层,支撑体孔隙被残炭缩小或填充,形成新的丰富孔隙结构。在炭化过程中,密中质组分发生熔融和颗粒间粘连,浸润支撑体孔隙和包裹其表面,较低终温时固化形成与支撑体紧密结合的连续致密分离层;其中,密中质组分脂肪族侧链和部分含氧官能团热分解生成气体逸出产生新的孔隙,随着热解温度的升高,热解更充分且气体析出速度加快,使分离层的孔数目增多,孔隙结构丰富,当温度升高到800℃,芳核自由基缩聚生成环数更多的芳香稠环大分子,促进小孔径孔的形成,同时使孔结构更规整。更多还原

【Abstract】 The sol of the coal dense medium component which was produced through the extraction and stripping was chosen as the coating liquid. Through the filming and charring, it was successfully prepared as coal-based ceramics-carbon composite membranes. The porosity, pure water permeability and rejection of Fe(OH)3 colloids and BSA solution of the composite membranes were characterized. The influences of membrane formation and carbonization conditions on the properties of separation layers were studied. The structural characteristics and pyrolysis behavior of the sol of the coal dense medium component, surface microstructure and pore size distribution were studied in evolution of separation layers by infrared analysis, thermal gravimetric analysis, scanning electron microscopy and pore size analysis.The results show that heating rate and final carbonization temperature are the most important factors on the rejection and porosity of the composite carbon membrane, and the number of coating times exerts an important effect on the permeability. The separation layer of composite carbon membrane with better performance can be prepared by the regulation of membrane formation and carbonization conditions. The carbon layers are formed from the dense medium component by drying and carbonization of the sol of the coal dense medium component coating. During the process, as the pores of support are reduced or filled with carbon residues, new structure with rich pores was formed. In the carbonization, the dense medium component melted and adhered with inter-particles, which infiltrated the pores and wrapped the surface of the support. When the final carbonization temperature is lower, the dense medium component forms a continuous and dense separating layer tightly binding with the support. In the process, the aliphatic side chain and partial oxygen-containing functional group of the dense medium component becomes gases and escapes to generate new porosity undergoing thermal decomposition. Upon rising the pyrolysis temperature, pore numbers of the separation layer increase and the pore structures become more abundant, for the pyrolysis being more complete and the gas evolution being speeding up. However, when the temperature is up to 800 ℃, the free radicals of aromatic nucleus are condensated to generate aromatic fused ring macromolecules with more rings, which promotes the formation of small holes and makes pore structure more regulation.更多还原