树脂基固态胺吸附剂室温下对低浓度CO2的吸附性能研究

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.

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

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^-1 and 150 mg·g^-1 were 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 of 139 mg·g^-1 was 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.