Preparation And Characterization Of Cellulose Based Carbon Dioxide Adsorbent Materials

As the greenhouse effect became increasingly,capture and separation of CO₂ has attached the global attention.Adsorption was considered for the best way to dealing with very of carbon dioxide.Cellulose is one of best natural polymer sources for the preparation of material with good environment friendliness and biocompatibility.Synthesed adsorptive material using cellulose as a raw material had great value for research and applicaton.The work focused on the preparation and characterization of cellulose based composite material as novel adsorbent towards carbon dioxide.The composite material was synthesized by combining cellulose with 13X molecular sieve in the presence of N-??-aminoethyl-?-aminopropyl?methyl dimethoxysilane as a coupling agent.The reaction conditions such as monomer mass and coupling agent dosage were studied.Based on the 13X molecular sieve/microcrystalline cellulose adsorbent,the powder molecular sieve/nano cellulose adsorbent was prepared.Then the morphology?structure and adsorption characteristics of CO₂ on the composite material were measured using FTIR?XRD?SEM?TG?BET?static and dynamic method investigated.The saturated adsorbents were regenerated by high temperature or vacuum,and the regenerative capacity of the adsorbents was evaluated.The results showed microcrystalline cellulose was the most suitable cellulose type for the synthesis of CO₂ composite adsorbent.Meanwhile,the analysis from SEM,EDX,BET,XRD,FTIR and TG indicated that the morphology of 13X molecular sieve was modified during the synthesis,leading to a decrease of most probable pore size from 27.1 nm to 13.9 nm.However,the micropore size and micropore volume were almost not affected.Compared with the absence of AEAPMDS,the as-prepared composite asorbdent with AEAPMDS exhibited even higher adsorption capacity and adsorption rate?1.31mmol/g?towards CO₂ at 298K and 1bar,accompanying an exothermic physisorption process with isosteric heat between 17 and 27kJ/mol.Moreover,CO₂ adsorption on the composite adsorbent at a low temperature?273K?reached as high as 1.83mmol/g at 1bar and the adsorption selectivity of CO₂ over N₂was above 50 at 0.5bar.Analysis of powder molecular sieve/nano cellulose adsorbent showed that the micropore size and micropore volume of powder molecular sieve were almost not affected.However,the total volume and probable pore size and were decreased to 2.95 nm.That exhibited even higher adsorption capacity and?2.86mmol/g?towards CO₂ at 273K and 1bar than 13X molecular sieve/microcrystalli ne ellulose adsorbent accompanying an exothermic physisorption process with isosteric heat between 9 and 22kJ/mol.and the adsorption selectivity of CO₂ over N₂was above 70 at 0.5bar.The coupling agent and gas flow rate played an important role in the dynamic adsorption and the regenerated sample had stable CO₂ adsorption performance.