Preparation of PEBAX-1074/modified ZIF-8 nanoparticles mixed matrix membranes for CO2 removal from natural gas

Abstract

In this work, as synthesized and modified ZIF-8 nanoparticles were used as the filler particles for mixed matrix membranes (MMMs) preparation for natural gas CO2 removal. Characterization of the prepared MMMs using SEM, XRD and FTIR were performed provided essential insights to the MMMs structure and revealed no defect in the MMMs due to incorporation of the ZIF-8 nanoparticles within the polymer matrix. The nanoparticles were also loaded by ethylenediamine (ED) amine loaded and incorporated within the PEBAX1074 matrix up to 20 wt% without agglomeration. After modification of the nanoparticles with ED, the ZIF-8 nanoparticles loading in the MMMs were extended up to 30 wt% without any agglomeration. The MMMs CO2 and CH4 adsorption and permeation rate were evaluated at the room temperature and different transmembrane pressures. The unmodified ZIF-8 nanoparticles loaded MMMs adsorption capacities for CH4 and CO2 were found as 6.28, 27.07 cm3 STP/cm3, respectively, compared with those of the modified ZIF-8 nanoparticles loaded MMMs were found as 6.88 and 30.46 cm3 STP/cm3, respectively. CH4 and CO2 permeabilities through the unmodified ZIF-8 nanoparticles loaded MMMs were found as ~9.39 and 134 Barrer, respectively, while for the modified MMMs, CH4 and CO2 permeation were measured as ~14.2 and 344 Barrer, respectively. The results showed significant improvement in ideal and real CO2/CH4 selectivity (71% and 40%) at 30 wt% of the ZIF-8 loading.