Preparation And CO₂ Capture Porous Materials With Large Pore Volume Functionalized By Amine

Carbon dioxide（CO₂）emissions from fossil fuel combustion and industrial processes account for as much as 65%of anthropogenic greenhouse gas emissions.The capture and sequestration of CO₂ is considered as a major solution to control the CO₂ concentration in the atmosphere.Currently,the technology of liquid amine adsorption is widely used as the traditional and commercial method for CO₂ capture,which exhibits high CO₂ adsorption capacity and selectivity.The method still has many drawbacks,including the equipment corrosion,degradation and evaporation of active component（amine）,high regeneration energy.The most economical and effective method is to develop solid amine adsorbents with ultra-high adsorption capacity for CO₂.Al₂O₃ samples with large pore volume were prepared by the thermal decomposition of ammonium aluminum carbonate hydroxide method（yeast method）.The pure ammonium aluminum carbonate hydroxide was obtained by the optimization of experimental conditions（reaction temperature 105℃,reaction time24h,the molar ratio of NH₄HCO₃/Al（OH）₃=8,ammonia 70ml）.The as-prepared Al₂O₃ samples were functionalized with Tetraethylenepentamine（TEPA）used as CO₂ adsorbent,which were characterized by XRD,N₂ adsorption-desorption,SEM and element analysis.CO₂ capture was evaluated in a fixed-bed microreactor at atmospheric pressure.At 75℃ Al₂O₃ with the TEPA addition of 50%showed a relatively high CO₂ adsorption capability（115.4 mg/g）.Also,it was suggested that amine-functionalized Al₂O₃adsorbents had the high stability and regeneration adsorption by adsorption-desorption cycles（12）.A series of silica materials with different pore volume were synthesized and functionalized by organic amine（TEPA）as CO₂ adsorbents.The effect of different pore-expanded agent and addition on the pore volume was studied.The SBA-15-PX-4.0 sample had a larger pore volume of 2.38 cm³/g.The as-synthesized adsorbents were characterize by XRD,SEM,TEM,nitrogen adsorption-desorption analyses.The CO₂ adsorption capability was performed in a fixed bed reactor operated using the mixture of CO₂（15.1%）and N₂as the model flue.Experimental results exhibited that the CO₂ adsorption capability increased with the pore volume of support.It was found that the CO₂uptake of S-60 reached 192.3 mg/g.It was suggested that pore volume was major factor influencing the adsorption capacity of adsorbents.Three-dimensionally ordered macroporous（3DOM）alumina was obtained using a colloidal crystal template method and functionalized by organic amine（TEPA）as CO₂ adsorbents.It was indicated that 3DOM-Al₂O₃ support showed the interconnected macroprous（200 nm）and mesoporous structure.3DOM-50 exhibited the high CO₂uptake（186.2mg/g）at atmospheric press and stable adsorption-desorption behavior during 12 consecutive test cycles,which was associated with its good 3DOM structure.3DOM-Al₂O₃ support provided“a namopool”for amine to adsorb CO₂,favored the accessibility of CO₂molecule to-NH₂group and reduce the resistance mass transport.