炭气凝胶及其有机气凝胶前驱体的吸附性能

间苯二酚和糠醛的醇溶液在六次甲基四胺催化下经溶胶-凝胶过程合成醇凝胶,常压干燥后得到有机气凝胶,经炭化获得炭气凝胶.利用TEM和N2吸附表征了炭气凝胶及其有机气凝胶前驱体的结构,并通过有机蒸汽吸附实验研究了气凝胶的结构-吸附性能关系.实验结果表明：有机气凝胶和炭气凝胶对极性有机蒸汽的静态饱和吸附量高于对非极性有机蒸汽的静态饱和吸附量;提高热处理温度,有利于气凝胶对低浓度极性有机蒸汽和各种浓度非极性有机蒸汽的吸附,但不利于对高浓度极性有机蒸汽的吸附;随着有机蒸汽浓度的提高,气凝胶对极性有机蒸汽的吸附量明显增大,但对非极性有机蒸汽的吸附量影响不大,仅略微上升.此外,气凝胶的室温脱附率高达60 %～85 %.

The adsorption of organic vapours on carbon aerogels and their precursor organic aerogels

Carbon aerogels were prepared by sol-gel polycondensation of resorcinol and furfural in alcohol using hexamethylenetetramine as a catalyst, and then directly drying the organic gels under conventional ambient pressure drying conditions, followed by carbonization under a nitrogen atmosphere. The structures of the organic aerogels and the carbon aerogels obtained were investigated by TEM and N2 adsorption-desorption analysis. Relationships between the structure and adsorption property of the carbon aerogels and their precursor organic aerogels were studied by the adsorption of organic vapor. It was found that both the organic aerogels and the carbon aerogels have a higher static adsorption capacity for polar organic vapors than that for non-polar organic vapors. With an increase of pyrolysis temperature, the aerogels have a higher adsorption capacity for the non-polar ben- zene vapor with various concentrations and for the polar ethanol vapor with a low concentration, but have a lower adsorption capacity for the polar ethanol vapor with a high concentration. With an increase in the concentration of the organic vapors, the adsorption capacity of the aerogels for the non-polar benzene vapor only slightly increases whereas that for the polar ethanol vapor sharply increases. In addition, the desorption efficiencies of the various organic vapors on the organic aerogels and on their related carbon aerogels at room temperature are up to 60 -85 %, and that on the former is higher than that on the latter.