In this study, a kind of functionalized graphene oxide (GO) membranes was fabricated. GO nanosheets were pre-coated by polydopamine (PDA) via spontaneous polymerization of dopamine (DA) and then cross-linked with zinc ions (Zn) via dopamine-mediated complexation reaction. The PDA coating rendered GO nanosheets a large number of evenly distributed oxygen-containing functional groups, which are beneficial to bond zinc ions effectively and to create favorable microenvironments of the nanochannels in GO membranes. Both PDA and Zn acted as cross-linkers to tune the interlayer spacing of GO nanosheets. Zinc ions also afforded facilitated transport ability towards CO in dry state. Taking CO/CH separation as the model system, the GO-PDA-Zn membrane exhibited significantly enhanced CO permeance of 175 GPU with CO/CH selectivity of 19.1 in dry state owing to the large transport channels and facilitated transport carriers. Moreover, the GO-PDA-Zn membrane exhibited high CO/CH selectivity of 32.9 in wet state owing to the stable intergalleries and moderate interlayer spacing. It is envisioned that the synergistic manipulation of PDA and metal ions can be utilized to exploit a variety of 2D membranes with superior gas separation performance.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors gratefully acknowledge the support from National Key R&D Program of China (2017YFB0603400), National Natural Science Foundation of China (No. 21490583 and 21621004), State Key Laboratory of Organic-Inorganic Composites (oic-201701004), National Science Fund for Distinguished Young Scholars (No. 21125627), State Key Laboratory of Separation Membranes and Membrane Processes (Tianjin Polytechnic University) (No. M1-201701 and No. M1-201501), the Program of Introducing Talents of Discipline to Universities (B06006), National Key Laboratory of United Laboratory for Chemical Engineering (SKL-ChE-17B01).