Investigation of transport properties of 6FDA-durene polymeric membrane for landfill gas application using molecular simulation approach

Abstract

Gas separation of carbon dioxide (CO₂) and methane (CH₄) from landfill gas (LFG) is very crucial to be undertaken to treat significant greenhouse gases (GHG) emitted to the atmosphere. Among the well-developed conventional technologies, membrane has drawn a huge attraction from many researchers to leverage on its application, which favors an efficient and environmentally safe process. In membrane technology, inorganic membrane type requires a complex and pricey fabrication process which is contradictory from the polymeric membrane features. The impressive gas permeability and acceptable value of selectivity possessed by polymeric membranes has contributed to its main attractiveness over the other types of membranes available. Besides, the frequent approach used which is through experimental methods requires complicated procedures and possess high difficulty to obtain a defect-free membrane sample. In this work, 6FDA-durene has been investigated by employing a molecular simulation approach to further examine its fractional free volume within the membrane matrix and transport properties. The structure creation of complete framework and the analysis of project deliverables has been adopted through a molecular dynamic simulation in Materials Studio software. FFV value obtained based on the simulated framework is 0.1743 which establishes about 3.15% deviation to the published experimental works. Upon the increment of operating temperature, most of the gasses would be in their activation condition and possess higher gas diffusivities and permeabilities. However, with increasing operating pressure simulation, the membrane framework was compressed and reached its asymptotic limit at 7 atm which acts as a maximum point when the membrane system becomes saturated. In both cases, the selectivity of CO₂/CH₄ gas pairs are validated with low percentage deviation (less than 10%) towards the reported experimental works hence affirms the reliability of results and methodology conducted.

Keywords: 6FDA-Durene; CO(2)/CH(4) separation; Membrane; Transport properties.