摘要
为了获得经济节能的烟道气CO2回收方法,制备了一种新型的N2优先渗透ZIF-8复合膜。以柔性聚砜(PSf)多孔膜为支撑层,采用Zn2+与壳聚糖的交联溶液对聚砜支撑层表面改性,使Zn2+固定在PSf膜表面;然后与2-甲基咪唑(Hmim)配位得到ZIF-8晶种层;最后通过界面聚合法二次生长制得ZIF-8复合膜。采用FTIR、XRD及SEM对ZIF-8复合膜的形貌结构进行表征,结果显示成功制备了致密的ZIF-8复合膜。在进料气为纯气条件下,探究了二次生长时间、Zn2+溶液的浓度、测试时间及测试压力对ZIF-8复合膜N2/CO2分离性能的影响,阐明其N2优先渗透机理;并进一步考察了混合气分离性能。结果表明:在25℃和0.1 MPa下,最优ZIF-8复合膜的N2渗透性为523 GPU,N2/CO2选择性为19;同条件下混合气的N2渗透性和N2/CO2选择性分别为517 GPU和18。所制备的ZIF-8复合膜可以使N2优先渗透,实现烟道气中高浓度N2渗透,低浓度CO2截留在膜的上游侧。原因主要是ZIF-8复合膜含有较多的CO2强吸附位点,使CO2被吸附在膜内不易从膜的下游侧脱附,渗透性小,而N2优先渗透,这为N2优先渗透膜的制备提供了一种新思路。
To improve the economic benefits of CO2 capture in flue gas,a novel N2 selective zeolitic imidazolate framework-8(ZIF-8)composite membrane has been designed in this work.The zinc ion(Zn^2+)was tightly adhered to the polysulfone support by chelating crosslinked chitosan matrix.The ZIF-8 seeding layer was prepared by zinc ion coordinated with 2-methylimidazole(Hmim),and then the dense ZIF-8 composite membrane was prepared by the secondary growth method.The morphological structure of ZIF-8 composite membrane was characterized by FTIR,XRD and SEM.And the results showed that the dense ZIF-8 composite membrane has been prepared.The effects of the time of secondary growth,the concentration of Zn^2+solution,the continuous test time and feed gas pressure on gas separation performance of ZIF-8 composite membrane were systematically investigated by pure gas,and the gas transport mechanism was analyzed.In addition,the separation performance of membranes was investigated by CO2/N2 mixed gas.At testing temperature of 25℃and feed gas pressure of 0.1 MPa,N2 permeance and N2/CO2 selectivity were 523 GPU and 19 for pure gas,respectively.While N2 permeance and N2/CO2 selectivity were 517 GPU and 18 for mixed gas under the same condition,respectively.The results showed that the ZIF-8 composite membrane could preferentially permeate N2 in the flue gas.The ZIF-8 composite membrane contained many CO2 active adsorption sites,so that CO2 was adsorbed in the membrane and was not easily desorbed from the downstream side of the membrane,and N2 could preferentially permeate,which provided a new idea for the preparation of N2 selective membrane.
作者
廉玉姣
王永洪
张新儒
李晋平
LIAN Yujiao;WANG Yonghong;ZHANG Xinru;LI Jinping(College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization,Taiyuan 030024,Shanxi,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2019年第9期3573-3581,共9页
CIESC Journal
基金
国家自然科学基金青年基金项目(21506140)
山西省煤层气联合基金(2015012009)
中国博士后基金(2016M601289)
山西省留学人员科技活动项目择优资助经费
作者简介
通信作者:张新儒(1984-),女,博士,副教授,zhangxinru@tyut.edu.cn;第一作者:廉玉姣(1994-),女,硕士研究生,lianyujiao678@163.com。
