球形与粉状4A沸石的锌交换及气体吸附性能研究

Zn(Ⅱ)-exchange and gas adsorption properties of spherical and powdered 4A zeolites

以一定浓度的Zn(Ⅱ)水溶液对3mm球形4A沸石分子筛进行离子交换,获得不同交换度的ZnNaA沸石。采用XRD、SEM及273K下的CO2吸附等温线表征了球形ZnNaA沸石的晶型、晶貌和微孔孔径分布。考察了不同交换度的球形ZnNaA沸石对CO2、CO、CH4和N2的吸附性能并与相同交换度的粉状样品进行比较。研究结果表明,在初始Zn(Ⅱ)浓度为0.1mol/L、时间为60min、固液比为0.1g/mL、温度为298K交换条件下,球形4A沸石与Zn(Ⅱ)交换的离子交换度最高可达45.6%,此时球形ZnNaA(45)沸石对气体吸附容量虽略低于粉状ZnNaA(42)沸石,但是其对气体的吸附选择性稍高于粉状ZnNaA沸石。

A zeolites with different degree of exchange were prepared by ion exchange of 3 mm spherical 4A zeolite with a certain concentration of Zn(Ⅱ)aqueous solution.XRD,SEM and CO2 adsorption isotherms at 273k were used to characterize the crystal form,morphology and pore size distribution of the ZnNaA zeolites.The adsorption properties of ZnNaA zeolites with different degrees of exchange on CO2,CO,CH4 and N2 were investigated and compared with that of the powder samples.The results showed that under the ion exchange conditions of initial Zn(Ⅱ)concentration of 0.1mol/L,time of 60min,solid-liquid ratio of 0.1g/mL,and temperature of 298K,the highest Zn(Ⅱ)ion exchange rate of spherical 4A zeolite was 45.6%.Although the gas adsorption capacity of spherical ZnNaA(45)zeolite was slightly lower than that of powdered ZnNaA(42),its gas adsorption selectivity was a little higher than that of powdered ZnNaA zeolite.