The effect of organic and ionic liquid solvents on structure crystallinity and crystallite size of ZIF-8 for CO2 uptake

In the present work, the effect of different synthesis solvents on the structure crystallinity, and the CO2 adsorption capacity of zeolitic imidazolate framework-8 (ZIF-8) has been investigated. In this regard, the synthesis of ZIF-8 using different organic and ionic liquid solvents, including Deionized (DI) water, acetone, ammonia, dimethylformamide (DMF), ethanol, and a synthesized ionic liquid (IL) in the presence of ultrasonic waves at room temperature was fulfilled. The obtained results unveiled that fabricated ZIF-8 using acetone and ionic liquid gives the smallest and largest crystal sizes around 17.7 and 27.6 ​nm, corresponded to the highest and lowest crystallinity respectively. Besides, TEM and N2 adsorption-desorption analyses illustrated higher crystallinity of acetone-synthesized ZIF-8 would result in lower particle size and higher BET surface area. Finally, the adsorption study shows that CO2 uptake on the ZIF-8 decreases from 150 to 95 CC(STP)/g at 1400 ​kPa when the acetone solvent is replaced by IL.