CO_(2)/N_(2)在MOF-74(Mg_(x)Zn_(1-x))上的吸附分离性能研究

Adsorption and Separation Performance of CO_(2)/N_(2) on MOF-74(Mg_(x)Zn_(1-x))

以Mg、Zn为中心金属,十二烷基苯磺酸钠(SDBS)为模板剂,采用溶剂热法合成HP-MOF-74(Mg_(x)Zn_(1-x))(x=0.25、0.5、0.75)材料,以CO_(2)和N_(2)为吸附质,考察了不同比例的HP-MOF-74(Mg_(x)Zn_(1-x))在273 K和298 K下吸附分离CO_(2)/N_(2)的性能。以烟道气CO_(2)和N_(2)为吸附质,使用静态容量法在273 K和298 K处测试了3种不同HP-MOF-74(Mg_(x)Zn_(1-x))材料上CO_(2)和N_(2)的等温线,并使用Virial模型对获得的实验数据集进行拟合。根据Henry系数估算了CO_(2)/N_(2)二元混合物的吸附选择性。此外,使用Virial方程计算等量吸附热(Q_(st))。结果表明:HP-MOF-74(Mg_(0.75)Zn_(0.25))样品在273 K和100 kPa下,CO_(2)的吸附量为1.90 mmol·g^(-1);Virial方程拟合CO_(2)和N_(2)曲线的相关系数都在0.999以上;273K下,HP-MOF-74(Mg_(0.25)Zn_(0.75))对CO_(2)的Henry吸附选择性为61.48;CO_(2)在3组样品HP-MOF-74(Mg_(x)Zn_(1-x))上的等量吸附热在均高于N_(2),说明CO_(2)在HP-MOF-74(Mg_(x)Zn_(1-x))样品上的表面自由结合能更高。

HP-MOF-74(Mg_(x)Zn_(1-x))(x=0.25,0.5,0.75)was synthesized by solvothermal method with Mg and Zn as central metals and sodium dodecylbenzene sulfonate(SDBS)as template.The adsorption and separation properties of different proportions of HP-MOF-74(Mg_(x)Zn_(1-x))at 273 K and 298 K were investigated.Using flue gas CO_(2) and N_(2) as adsorbents,the isotherms of CO_(2) and N_(2) on three different HP-MOF-74(Mg_(x)Zn_(1-x))materials were measured at 273 K and 298 K by static volumetric method,and the experimental data sets were fitted by Virial model.The adsorption selectivity of CO_(2)/N_(2) binary mixture was estimated according to Henry coefficient.In addition,the isosteric heat of adsorption(Q_(st))was calculated using the Virial equation.The results showed that HP-MOF-74(Mg_(0.75)Zn_(0.25))sample had CO_(2) adsorption capacity of 1.90 mmol·g^(-1) at 273 K and 100 kPa;The correlation coefficients of CO_(2) and N_(2)curves fitted by virial equation were more than 0.999;At 273 K,the Henry adsorption selectivity of HP-MOF-74(Mg_(0.25)Zn_(0.75))for CO_(2) was 61.48;The isosteric adsorption heat of CO_(2) on HP-MOF-74(Mg_(x)Zn_(1-x))was higher than that of N_(2),indicating that the surface free binding energy of CO_(2) on HP-MOF-74(Mg_(x)Zn_(1-x))was higher.