Separation performance study of metal organic framework (MOF) based mixed matrix membrane for CO2 and CH4

Abstract

The CO2 capture is important not only in fuel upgrading but also for controlling global warming issues. The fossil fuels are major source of energy, which are the main contributors of greenhouse gas emission. So it is necessary to separate these gases. For controlling CO2 emission, membrane technology has great potential because of its low energy consumption and maximum efficiency. Therefore, the work is designed to separate CO2 from CH4 with the help of membrane. In this study, a novel bimetallic NiO/CuO MOF based mixed matrix membranes (MMMs) were fabricated from polysulfone (PSf) and polyethylene glycol (PEG), and investigated for gas separation application. Polysulsone (PSf) was used as main polymer matrix, while polyethylene glycol (PEG) and NiO/CuO MOF were used as plasticizer and filler respectively. The four different composition of filler (NiO/CuO MOF) i.e. 0.05%, 0.1%, 0.15%, 0.2% and 2% of additive (PEG) was incorporated with polysulfone (PSf) to evaluate the results. All prepared membranes were characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) techniques. The obtained results revealed defects free membranes. The structure confirmed that MOF particles were uniformly embedded, which is the confirmation of good affinity of filler (NiO/CuO MOF) as well as additive/plasticizer (PEG) with polysulfone matrix. Furthermore, mechanical testing implied that by adding NiO/CuO MOF in Polysulfone, brittleness appeared and strength decreased from 2.84 MPa to 2.26 MPa. However, the strength increased to 4.11 MPa by adding PEG as plasticizer. The permeation was also performed to investigate the performance of pure PSf, PSf/MOF, PSf/PEG and PSf/PEG/MOF membranes. By adding 0.2% NiO/CuO Pyrazize and BDC MOF with 2% PEG, the CO2 permeability increased from 6.82 Barrer (for pure PSf membrane) to 17.13 Barrer (for PSf/PEG with NiO/CuO MOF based membrane). Moreover, the best CO2/CH4 selectivity achieved was 20.70 for the same membrane at the pressure of 5 bar. The separation performance study was investigated in the pressure range of 2 to 5 bar, at room temperature. The study revealed a great potential of MMMs for CO2 gas separation application.