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应用量子化学密度泛函理论,在6-311 g水平上对建立的吸附模型进行全优化。结果表明,煤的表面能够与多组分气体发生混合吸附。煤表面吸附氧、氮和二氧化碳分子组成的吸附态中,氧分子和氮分子在煤表面的侧链吸附,CO_2则在苯环的上方。煤表面氨基上的C原子和N原子的电子向氧分子中的氧原子转移。煤表面吸附了二氧化碳和氮分子,氧分子所得的电子减少,表明如果煤表面吸附其它种类分子,则削弱了吸附氧的作用。吸附后O_2的频率变化较大,N_2和CO_2的频率变化很小。煤表面与矿井采空区各种气体发生吸附时的亲和顺序为:氧气>水>二氧化碳>氮气>一氧化碳>甲烷。
Quantum chemical density functional theory was used to optimize the adsorption model established at the level of 6-311 g. The results show that the surface of coal can be mixed with multi-component gas adsorption. Oxygen, nitrogen and carbon dioxide molecules adsorbed on the surface of coal adsorption, oxygen molecules and nitrogen molecules in the coal side of the adsorption surface, CO_2 in the benzene ring above. The C atoms and N atoms on the amino surface of the coal transfer oxygen atoms to oxygen molecules. Carbon dioxide and nitrogen molecules are adsorbed on the surface of the coal, and the electrons obtained from the oxygen molecules decrease, indicating that if the coal surface adsorbs other kinds of molecules, the role of adsorbed oxygen is weakened. The frequency of O 2 changes greatly after adsorption, and the changes of the frequency of N 2 and CO 2 are small. The order of affinity for the adsorption of gases on the coal surface and the goaf is: oxygen> water> carbon dioxide> nitrogen> carbon monoxide> methane.