粉煤灰基沸石X的制备与邻二甲苯、CO_(2)和H_(2)的吸附应用

Preparation of Coal Fly Ash-Based Zeolite X and Its Adsorption Application for O-Xylene, CO_(2), and H_(2)

本文通过探索碱熔活化条件,获得了最优的活化粉煤灰的条件(400℃,m(氢氧化钠)∶m(粉煤灰)=1∶2),并且在80℃下水热合成18 h获得了相对结晶度最高的粉煤灰基沸石X,通过XRD、FT-IR、SEM、BET等表征了粉煤灰基沸石X的物理特征。结果表明,合成沸石的相对比表面积达315.6 m^(2)/g,平均孔径为8.53 nm,总孔容积为0.412 cm^(3)/g。粉煤灰基沸石X展现了显著的邻二甲苯、二氧化碳和氢气吸附能力,分别为75.20 mg/g、2.45 mmol/g和0.22%(质量分数),且其吸附行为可以被Langmuir吸附等温线很好地拟合,属于单分子层吸附。本研究降低了粉煤灰沸石化过程中的能源消耗,并且所制备的粉煤灰基沸石X在能源和环境保护方面具有潜在的商用价值。

The optimal conditions for activating coal fly ash(400℃,m(NaOH)∶m(coal fly ash)=1∶2)were obtained by exploring the alkali fusion activation conditions,and the coal fly ash-based zeolite X with the highest relative crystallinity was obtained by hydrothermal synthesis at 80℃for 18 h.The physical characteristics of synthesized zeolite X were characterized by XRD,FT-IR,SEM,and BET.The results show that the synthesized zeolite obtains a relatively specific surface area of up to 315.6 m^(2)/g,an average pore diameter of 8.53 nm,and a total pore volume of 0.412 cm^(3)/g.Coal fly ash-based zeolite X also shows higher adsorption capacity of o-xylene,carbon dioxide and hydrogen,which are 75.20 mg/g,2.45 mmol/g,and 0.22%(mass fraction),respectively.The adsorption behavior can be well fitted by Langmuir adsorption isotherm,which belongs to monolayer adsorption.This study reduces the energy consumption in the zeolite process of coal fly ash,and the prepared coal fly ash-based zeolite X has potential commercial value in energy and environmental protection.