The modern global climate change and global warming of Earth make it an urgent need to develop emerging CO2 capture and storage techniques. Herein, we first reported the use of WS2 nanosheets to construct laminated membranes for CO2 separation. However, the WS2 membrane showed poor CO2 separation performance with Knudsen selectivities for N2/CO2 (1.28), CH4/CO2 (1.72) and H2/CO2 (4.96). To improve the performance, an ionic liquid (IL) 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF4]) with high CO2 solubility and practically no vapour pressure was used for filling the nanochannels of the WS2 membrane. Compared to the bulk IL, the nanoconfined IL exhibits higher freezing temperature, shift of vibration bands and higher interaction energy between CO2 and ILs. Besides, the prepared WS2 laminated membrane with the nanoconfined ionic liquid shows excellent selectivities for CO2/N2 (153.21), CO2/CH4 (68.81) and CO2/H2 (13.56) in single gas measurements as well as good CO2 permeance due to the nanoconfinement of the IL. The simulation results further confirmed and explained the CO2 separation mechanism. It indicates that the nanoconfinement of ILs into the nanochannels of two-dimensional materials is a novel way to achieve CO2-philic membranes to efficiently separate CO2 from other light gases.
Bo Wen,Gaopeng Wang,Renze Xu,Chenglong Weng,Jintao Yang
With the growing global emphasis on environmental protection, supercritical CO 2 foaming technology for biodegradable materials such as polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS) and their blends has emerged as a research and application hotspot. However, the low melt strength and poor compatibility of these polymers often lead to low nucleation efficiency, cell wall rupture and coalescence, exhibiting inferior foaming performance. In this work, aiming to enhance the foamability of PLA and PLA/PBAT blends, a fluorinated chain extender, F-CE (GMA-co-DFHA-co-MMA), was designed and synthesized. Through the reactive melt blending, F-CE effectively enhanced the melt strength of PLA and interfacial adhesion between PLA and PBAT, leading to a significant improvement in foaming performance. Additionally, the fluorine groups in DFHA demonstrated high affinity for CO 2 , providing additional heterogeneous nucleation sites for bubble formation, thereby increasing both foam expansion ratio and cell density. Notably, the F-CE/PLA foam exhibited a cell diameter of ∼13.8 μm with an exceptionally high expansion ratio of ∼35. As a contrast, pristine PLA foam shows an expansion ratio of ∼30, but with large cell diameter (∼118 μm). Although PLA foam containing CE without fluorine (CE/PLA foam) exhibits small cells with an average cell diameter of ∼13.6 μm, the expansion ratio is low (∼23). In addition, F-CE also exhibits superior performance in improving the foamability of PLA/PBAT blends. This work presents a chain extender specifically engineered for foaming applications, which functions as a highly efficient foaming additive to holistically enhance the foaming performance of polymers.
危险品化学品经营许可证（带存储）