高选择性PEI@MOF-808吸附剂在潮湿烟气中的碳捕集性能研究

Study on the carbon capture performance of highly selective PEI@MOF-808 adsorbent in humid flue gas

以Zr基金属有机框架MOF-808为载体,采用聚乙烯亚胺(polyethylenimine, PEI)进行官能化,得到PEI@M-808复合材料,用于选择性捕集潮湿烟气(10%CO_(2)+90%N_(2)+10 kPa H_(2)O)中的低浓度CO_(2)。采用XRD、FT-IR、SEM以及BET等表征了吸附剂的物理化学性质,并评估改性方案的可行性。由于MOF-808表面PEI的负载引入了丰富胺基官能团,使复合吸附剂在低浓度CO_(2)下的吸附性能大幅提升。PEI300-30@M-808在典型烟气温度(343 K)的低压CO_(2)吸附量相比原材料由0.052 mmol/g上升到0.89 mmol/g,增加了约16倍。此外,CO_(2)/N_(2)吸附选择性在0.1 bar (1 bar=10~5 Pa)时能达到5524.65,相比原材料提升了约56倍。更重要的是,当吸附剂放置到5%RH工况中时吸附量由0.89 mmol/g提高到1.47 mmol/g,证明了水分对其CO_(2)吸附起着良好的促进作用。经过5次循环后,PEI300-30@M-808的CO_(2)饱和吸附量仍可维持在90.7%。

Zr-based metal organic framework MOF-808 is used as the carrier and is functionalized with polyethylenimine(PEI)to obtain PEI@M-808 composite material,which is used to selectively capture humid flue gas(10%CO_(2)+90%N_(2)+10 kPa H_(2)O).The physicochemical properties of the sorbents are characterized by XRD,FT-IR,SEM,and BET techniques,and the effectiveness of the modification scheme is assessed.The sorption performance of PEI300-30@M-808 at trace CO_(2) with moisture is dramatically enhanced due to the abundant amine groups on the surface of PEI@M-808 corresponding to the loading of PEI molecules.The adsorption performance of the composite adsorbent at trace CO_(2) concentration is greatly enhanced by the introduction of abundant amine functional groups on the surface of MOF-808 due to the loading of PEI.The PEI300-30@M-808 could trap 0.89 mmol/g at 343 K and 0.1 bar while the MOF-808 manifests sorption capacity of approximately 0.052 mmol/g under the same condition.Furthermore,the sorption selectivity of PEI300-30@M-808 is 5524.65 at 10/90 CO_(2)/N_(2) at 0.1 bar and 343 K,which is about 56 times larger compared to that of MOF-808.Additionally,per gram of PEI300-30@M-808 could react with 1.47 mmol/g at the sorption condition with 5%RH,indicating that the moisture has a positive effect for CO_(2) capture with PEI-based materials.After 5 cycles,the CO_(2) saturated adsorption capacity of PEI300-30@M-808 can still be maintained at 90.7%.Therefore,the PEI300-30@M-808 feature great potential for trace carbon capture in moist flue gas.