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作 者:张守玉[1] 王洋[2] 吕俊复[1] 岳光溪[1]
机构地区:[1]清华大学热能工程系,北京100084 [2]中国科学院山西煤炭化学研究所,山西太原030001
出 处:《煤炭学报》2003年第5期531-536,共6页Journal of China Coal Society
基 金:国家重大基础研究规划资助项目(G1999022204)
摘 要:在一流化床上制备彬县煤活性焦,利用X射线光电子能谱(XPS)等分析手段考察了活化条件对制得的彬县煤活性焦表面性质的影响.结果表明:活性焦表面多环芳香系统的离域π电子是活性焦碱性的主要来源;活化温度提高,在活性焦表面上的离域π电子的电子给体-受体作用增强,活性焦表面碱性增强.究其原因是活化温度提高,一方面有利于活性焦孔隙结构的发展,从而使得更多的表面多环芳香系统暴露于外部空间;另一方面有利于活性焦表面结构的重排,形成多环芳香系统,同时,由于氧的逸出,使得多环芳香系统上的π电子离域效应增强所致.The effects of activating conditions on the surface properties of the activated chars prepared from Binxian coal on a batch fluidized bed were investigated using X ray photoelectron spectroscopy (XPS) and other analytical methods. The results show that the basicity of the activated chars arises from the itinerant π electrons within the system of polynuclear aromatic ring on the surface of activated chars. It is also found that the increase of activating temperature results in the increase of the number of the itinerant π electrons and then enhances the basicity of the activated chars. The reasons may be as follows: (1) The increase of the activating temperature favors the development of the porous structure in the activated chars and more and more polynuclear aromatic rings are exposed. (2) The increase of the activating temperature is propitious to the resetting of the surface structure in activated chars and then results in the formation of polynuclear aromatic rings. (3) More oxygen incorporated into the edge sites of the surface carbon structure is dismissed because of the increase of the activating temperature and this lead to the decrease of localization of π electrons towards the periphery of polynuclear aromatic rings.
分 类 号:TQ522[化学工程—煤化学工程]
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