Synthesis of Amino-Impregnated ZIF-8 for CO2 Adsorption

Abstract

Zeolitic imidazolate framework-8 (ZIF-8) is well known for its high thermal stability, high surface area and remarkable water stability as compared to the other adsorbents. However, ZIF-8 shows relatively low CO2 capture ability. In this work, ZIF-8 is modified with amino-groups via wetness impregnation method and the performance of the resultant adsorbents in CO2 capture is investigated. Two different types of amino-groups including tetraethylenepentamino (TEPA) and pentaethylenehexamino (PEHA) were used. The concentrations of TEPA and PEHA were prepared at 30, 50 and 70 volume% in chloroform solution, respectively, prior to impregnation over ZIF-8. The Fourier transform infrared (FTIR) results showed that, successful incorporation of amino groups into ZIF-8 was achieved. Meanwhile, based on SEM images, severe agglomeration of particles was observed for 50% and 70% TEPA and PEHA-impregnated ZIF-8. Subsequently, it was found that ZIF-8 impregnated with 30 % TEPA showed the highest CO2 adsorption capacity of 1.9983 mmol g-1 as compared the other adsorbents prepared in this work. This has signified the improvement of CO2 adsorption capacity by using amino-impregnated ZIF-8, which was up to 199.6% compared to the parent ZIF-8. Overall, the adsorbents developed in the present work are potential to be used in the industrial CO2 adsorption processes.