摘要
以研制吸附式天然气(ANG)用金属有机骨架材料(MOFs)吸附剂为目的,在温度区间283.15~303.15K、压力范围0~9.5MPa,测试并分析了甲烷在制备MOF-5和MOF-199试样上的吸附平衡。首先,运用机械化学法和溶剂热法合成MOF-5和MOF-199,合成试样经XRD衍射、SEM微观形貌观察和热重分析,并由77.15K氮的吸附数据表征样品的孔大小及分布、比表面积和微孔容积。其次,选择极低压力下的吸附平衡数据标定亨利定律常数,确定甲烷在两吸附剂上的极限吸附热。最后,依据测试的甲烷在两种吸附剂上的高压吸附平衡数据,比较了由试验数据关联Langmuir系列方程参数后预测数据的累计相对误差,并由累计相对误差最小的Toth方程计算绝对吸附量后标绘确定甲烷在两试样上的等量吸附热。结果表明,在测试的温度压力范围内,Toth关联方程预测甲烷在MOF-5和MOF-199上吸附平衡数据的累计相对误差为3.17%和4.05%,甲烷在制备MOF-5和MOF-199试样上极限吸附热和等量吸附热的平均值分别为17.33kJ/mol、11.93kJ/mol和20.65kJ/mol、16.34kJ/mol。MOF-199对甲烷分子有较强的吸附作用。
In order to develop adsorbents for adsorption natural gas(ANG),the adsorption equilibriia of methane on MOF-5 and MOF-199 samples were measured in the temperature range of 283.15-303.15K and the pressure range of 0-9.5MPa.The MOF-5 and MOF-199 samples were synthesized by mechanochemical and solvothermal methods and characterized by XRD,SEM and TG.The pore size and distributions,specific surface areas and micropore volumes of the samples were determined by the adsorption isotherms of nitrogen measured at 77.15K.The limit adsorption heats of methane on the samples were determined by using the adsorption equilibrium data at very low pressure to calibrate Henry's law constants.Adsorption data volumetrically measured under high pressures were correlatively fitted by Langmuirian equations through nonlinear regressions.Toth equation having the smallest accumulative relative error in predicting adsorption data was then used to calculate the absolute adsorption amounts,which were finally employed to calculate the isosteric heat of adsorption via Clausius-Clapeyron equation.It shows that the accumulative relative errors of Toth equation in predicting the adsorption data are 3.17%and 4.05%,respectively,for MOF-5 and MOF-199.Results also reveal that the mean limit isosteric heats of methane adsorption on the MOF-5 and MOF-199 are 17.33 kJ·mol^-1 and 20.65 kJ·mol^-1,respectively,and the mean isosteric heats are 11.93kJ·mol^-1 and 16.34kJ·mol^-1,respectively.Compared with MOF-5,MOF-199 has stronger adsorption on methane.
作者
张维东
郑青榕
王泽浩
张轩
ZHANG Wei-dong;ZHENG Qing-rong;WANG Ze-hao;ZHANG Xuan(Provincial Key Laboratory of Naval Architecture&Ocean Engineering,Institute of Marine Engineering,Jimei University,Xiamen 361021,China)
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
2019年第6期45-51,共7页
Natural Gas Chemical Industry
基金
国家自然科学基金(51979121)
厦门市科技计划(3502Z20173026)项目资助
关键词
甲烷
MOFS
吸附模型
等量吸附热
methane
MOFs
adsorption model
isosteric heat of adsorption
