A型沸石/活性炭复合材料的制备及甲烷/氮气吸附分离性能

以沥青和煤矸石为原料,经炭化、活化后获得型体活性炭材料(AC),并在此基础上进行水热晶化,研究晶化时间对复合材料中4A沸石的形成、孔结构和甲烷、氮气吸附性能的影响。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、77 K下的氮气吸附-脱附以及273 K下的CO_2吸附等温线对样品进行表征,结果表明水热晶化后,复合材料中的硅铝形成立方结构的4A沸石,出现了0.45~0.6 nm的微孔,微孔孔容增加,并伴有少量的中孔和大孔。复合材料在298 K下的甲烷(CH_4)和氮气(N_2)吸附等温线的结果表明,晶化时间6 h的复合材料AC-2的甲烷吸附量被提高至10.8 m L/g,并保持较高的CH4/N2平衡分离比(3.7)。

Synthesis of Zeolite A/Activated Carbon Composite and CH4/N2 Adsorption Separation Performance

A shaped activated carbon(AC) prepared after carbonization and physical activation, starting from pitch and elutrilithe, was further hydrothermally treated with alkaline solution. The effect of crystallization time on the formation of zeolite 4A, the pore structure and the adsorption ability of the composite towards CH₄ and N₂ were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), N₂ adsorption-desorption at 77 K and CO₂ adsorption isotherm at 273 K. The results show that silicon and aluminum in this composite are converted to zeolite 4A during the hydrothermal treatment. Simultaneously, micropores between 0.45~0.6 nm are appeared, the micropore volume is increased, accompanied by the presence of a few mesopores and macropores. Adsorption isotherms at 298 K indicate that the adsorption amount of CH₄ by composite AC-2(crystalized for 6 hours) is elevated to 10.8 mL/g with a high CH₄/N₂ equilibrium selectivity of 3.7.