树脂基固态胺吸附剂室温下对低浓度CO_2的吸附性能研究

Ambient temperature sorption of low-concentration carbon dioxide on resinbased solid amine sorbents

以大孔甲基丙烯酸酯吸附树脂为载体,聚乙烯亚胺(PEI)为有机胺,采用液相浸渍法制备出固态胺吸附剂,并研究了其在室温下对低浓度CO2的吸附行为.同时,利用氮气吸附、热重分析和扫描电镜表征了材料的物理化学性质,并采用热重法和固定床吸附法考察了材料的CO2吸附性能.结果表明,大孔树脂担载50%PEI(质量分数)时吸附性能最佳,对纯CO2的最大吸附量为175 mg·g-1;CO2的吸附行为由扩散动力学与吸附热力学共同决定,低温有利于提高吸附容量;吸附剂对400 ppm^15%浓度的CO2都具有优异的动态吸附性能,其中对400 ppm CO2的吸附量达到86 mg·g-1,对15%CO2的吸附量达到150 mg·g-1;湿度对吸附起促进作用,相对湿度为10%时,对400 ppm CO2的吸附量提高至139mg·g-1;吸附剂具有优异的循环性能,具有直接空气捕集CO2的潜力.

Resin-based solid amine sorbents were developed by macroporous adsorption resin impregnated with polyethylenimine(PEI) for regenerative ambient-temperature removal of low concentration CO2.The physicochemical properties of the sorbent were characterized by N2 adsorption /desorption,scanning electron microscopy(SEM) and thermal gravimetric analysis(TGA) followed by tests for CO2 capture using TGA and fixed bed experiment.The optimal PEI loading was 50% with a pure CO2 sorption capacity of 175 mg·g-1.The sorption behavior was determined by the kinetic diffusion and thermodynamic sorption.Low temperature favored the thermodynamic sorption and resulted in high sorption capacity.The sorbents had excellent CO2 sorption capacities over the concentration rang of 400 ppm~ 15%.The sorption capacities as high as 86 mg·g-1and 150 mg·g-1were obtained for 400 ppm CO2 and 15% CO2 flow,respectively.The humidity played a promoting role on the sorption capacity of 400 ppm CO2,and a remarkable improvement of139 mg·g-1was achieved for a relative humidity of 10%.The sorbents also exhibited stable sorption /desorption cycling performance.All these results suggested that the as-prepared solid amine sorbents had a great potential in room-temperature direct air capture of CO2.