Chitosan/ZIF-8 Composite Beads Fabricated by In Situ Growth of MOFs Crystals on Chitosan Beads for CO2 Adsorption

摘要

CO2 responsive polymer chitosan is introduced to fabricate polymer/MOFs composite materials used to explore CO2 adsorption and recyclability.Chitosan beads(CBs)are successively immersed in the solution of Zn~(2+)and the solution of 2-methylimidazole to fabricate chitosan/ZIF-8 composite beads(CBsZx)by in situ growth of ZIF-8 crystal on chitosan beads.CBsZx are characterized by powder XRD,FT-IR,SEM,TEM,TGA and BET.The morphology,size and distribution of the ZIF-8 crystals on CBsZx are tuned by adjusting the concentration of Zn~(2+)in the soaking solution.The coordination of the free amino groups on chitosan skeleton with Zn~(2+)and selfemulsifying properties of chitosan have played a key role in situ growth of the ZIF-8 crystals on chitosan beads.Additionally,the adsorption capacity and recyclability of CBsZx for CO2 has been evaluated.Compared with the pure ZIF-8 crystals,the adsorption capacity of CBsZx for CO2 is significantly enhanced by 90%.The kinetic models indicate that the adsorption of CBsZx for CO2 belongs to physical adsorption,when the ZIF-8 crystals on chitosan beads have the regular shape and size.Moreover,the adsorption capacity of CBsZx for CO2 is remained more than 80% after 3 recycling.