分子量和NaY添加量对炭分子筛膜CO_(2)分离性能的影响

Effects of molecular weight and NaY addition on separation performance of carbon molecular sieve membrane for CO_(2)

以均苯四甲酸酐(PMDA)和二氨基二苯醚(ODA)为原料,通过改变反应时间和反应温度制得不同分子量的聚酰胺酸(PAA),然后通过原位掺杂NaY制得炭分子筛膜(CMSMs),用于CO_(2)分离性能研究.考察了前驱体分子量及无机填料对CMSMs气体分离性能的影响,同时测试了混合气分离性能,并研究了CMSMs的老化过程.结果表明,PMDA和ODA在0~5℃下反应6.5h后合成的PAA分子量最大,为13.55×10^(4),其对应的CMSMs的CO2渗透系数和CO_(2)/N_(2)选择性分别为291 Barrer和30.5.随着NaY含量的增加,CMSMs的CO_(2)渗透系数逐渐增加,而CO_(2)/N_(2)选择性先增大后减小;当NaY掺杂量为6%时,所制备的CMSMs的气体分离性能达到最优(CO_(2)渗透系数为699 Barrer,CO_(2)/N_(2)选择性为47.6).混合气分离性能测试表明,CMSMs的气体分离性能略低于纯气.在70 d的老化测试中,CMSMs气体分离性能表现出良好的稳定性,表明其具有一定的工业应用价值.

Polyamic acid(PAA)with different molecular weights are prepared by changing the reaction time and reaction temperature with pyromellitic anhydride(PMDA)and diaminodiphenyl ether(ODA)as raw materials.Na Y inorganic fillers are doped into the prepared PAA in situ to prepare carbon molecular sieve membrane(CMSMs),which is used for studying separation performance to CO_(2).The effects of PAA molecular weight and Na Y on the gas separation performance of CMSMs are investigated,and their separation performance for mixed gas is also tested.The aging process of CMSMs is investigated.Results indicate that PAA with the maximum molecular weight 13.55×10^(4)g·mol^(-1) can be obtained if the reaction between PMDA and ODA occurs at 0-5℃ for 6.5 h.The permeability coefficient of CO_(2) over CMSMs derived from PAA with the maximum molecular weight is 291 Barrer and the selectivity of CO_(2)/N_(2) over that is30.5.With the increasing of Na Y loading,the permeability coefficient of CO_(2) over CMSMs increases gradually while the selectivity of CO_(2)/N_(2) by CMSMs increases firstly and decreases then.As the doping amount of Na Y is 6 wt%,the prepared CMSMs exhibits the optimal gas separation performance,with a CO_(2) permeability coefficient of 699 Barrer and a CO_(2)/N_(2) selectivity of 47.6.The separation performance of CMSMs to mixed gas is slightly lower than that to pure gas.In a 70-day aging test,CMSMs’gas separation performance shows a good stability,indicating that it has certain industrial application value.