Preparation Of ?-complexation Reaction Facilitated Transport Membranes With Enhanced CO₂ Separation Performance

The development of CO₂ separation technology can provide an important basis for addressing climate change and achieving global low carbon green development.Membrane separation technology has become one of the most popular CO₂ separation technology because of its low energy consumption,high efficiency,mild conditions,simple operation and so on.Design and development of membrane materials with high performance is the key of membrane separation technology.A series of membrane materials based on?complexation reaction have been designed.Through the adjustment of the membrane matrix-interface-surface structure,the integrated optimization of membrane solubility-diffusivity-reaction multi-selection mechanism is realized,and finally the membrane permeability and selectivity are strengthened simultaneously.Based on synergistic enhancement of solubility-based and reaction-based selection mechanism:hybrid membranes are prepared with sulfonated pitch particles containing zinc ion(SP-Zn²⁺)as the filler and Pebax^?1657 as the membrane matrix.The solubility-based selection mechanism of membrane is enhanced by utilizing the affinity between sulfonate and CO₂.Zinc ion,as the CO₂ carrier,introduces?complexation mechanism into the membrane.Compared with Pebax membrane,the CO₂ permeability and CO₂/CH₄ selectivity of the Pebax/SP-Zn²⁺?2?hybrid membrane are increased significantly by 104%and 70.2%.Based on synergistic enhancement of diffusivity-based and reaction-based selection mechanism:hybrid membranes are prepared with graphene oxide containing zinc ion(GO-DA-Zn²⁺)as the filler and Pebax^?1657 as the membrane matrix.GO nanosheets make the gas transport channels more tortuous and then strengthen the diffusivity-based selection mechanism of membrane.High specific surface area of GO and strong metal ion complexation capacity of PDA ensure the high stability of zinc ion in the membrane.In addition,the Pebax/GO-DA-Zn²⁺hybrid membranes exhibit the enhanced CO₂ separation performance with CO₂ permeability of 137.9 Barrer and CO₂/CH₄ selectivity of 30.6,which are 49%and 78%higher than those of Pebax membrane.Based on synergistic enhancement of solubility-based,diffusivity-based and reaction-based selection mechanism:GO composite membranes,which take both PDA and zinc ion as crosslinking agent,are designed.Due to the good affinity between CO₂ and PDA layer on the surface of the membrane,it is advantageous to strengthen the solubility-based selection mechanism of membrane.Besides PDA and zinc ion are applied to adjust the layer spacing of GO in order to realize the size sieving.Meanwhile,zinc ion existed in the membrane channels can also play a role in facilitating CO₂ transport.The CO₂ permeation rate and CO₂/CH₄ selectivity of GO-DA-Zn²⁺?1?/PES membrane under dry condition are 175 GPU and 19.1respectively,increased by 661%and 91%compared with those of GO membrane.