基于不同尺寸ZIF-8多孔液体的二氧化碳捕集性能

Carbon dioxide capture performance of porous liquids based on ZIF-8 with different sizes

摘要:

通过尺寸调控策略制备了基于不同尺寸ZIF-8的多孔液体（PLs），并用于CO2的捕集。结合理论和CO2吸附实验数据 ，证实了多孔液体中具有永久的孔隙结构；黏度测定结果表明，不同多孔液体均具有优异的流动性。三种不同尺寸的多孔液体室温下放置60 d或4500 r/min下离心5 min后均未出现聚集、沉积现象，表明不同尺寸多孔液体均具有较好的稳定性。考察了ZIF-8尺寸对多孔液体捕集CO2容量、速率、CO2/N2选择性及循环稳定性的影响，并对不同尺寸多孔液体的CO2吸附动力学进行研究。结果表明，利用不同尺寸ZIF-8合成的多孔液体吸附CO2过程包括物理吸附和化学吸附两种方式。其中，ZIF-8尺寸为43 nm的多孔液体ZIF-8-PLs(43) 对CO2的饱和吸附量最大，为63.0 mg/g；ZIF-8-PLs(145)展现了较快的CO2吸附速率，动力学常数为1.91×10-3 g/(mg?min)； ZIF-8-PLs(1400)具有最高的CO2/N2选择性，是ZIF-8-PLs(43)的4.8倍；三种多孔液体经过5次循环后均具有较好的循环稳定性。

Abstract:

Porous liquids (PLs) based on ZIF-8 with different particle sizes for CO2 capture were prepared through particle size control strategy. Combined with theoretical and experimental data of CO2 adsorption, it was confirmed that PLs had permanent pore structure. Viscosity experiments showed that different PLs have excellent fluidity. The three porous liquids of different sizes showed no aggregation and deposition after placement at room temperature for 60 d or centrifugation at 4500 r/min for 5 min, indicating that the PLs of different sizes have excellent stability. The influence of ZIF-8 sizes on the CO2 capture capacity, rate, CO2/N2 selectivity and cycling stability of PLs was studied, and the CO2 adsorption kinetics of PLs with different sizes were studied. The result showed that the CO2 adsorption by PLs based on ZIF-8 with different particle sizes includes physical adsorption and chemical adsorption. Among them, The ZIF-8-PLs(43) with the ZIF-8 size of 43 nm had the highest saturation CO2 adsorption capacity with 63.0 mg/g; ZIF-8-PLs(145) exhibited a faster CO2 adsorption rate with a kinetic constant of 1.91×10-3 g/(mg?min); ZIF-8-PLs(1400) had the highest CO2/N2 selectivity, which was 4.8 times higher than that of ZIF-8-PLs(43); All three PLs had excellent cycling stability after 5 cycles.