• Daramola, Michael O.

Abstract

The continuous anthropogenic carbon dioxide (CO2) emission into the atmosphere in the past decades with its associated global climate changes and other environmental disasters has received substantial attention worldwide. Other greenhouse gases (GHG) such as methane are likewise emitted but research findings indicated CO2 as the major pollutant, requiring urgent attention to combat climate change. Thus mitigating the climate change through reduction of CO2 emission constitutes a technological and scientific challenge [1]. However, numerous technologies (absorption, adsorption and membrane technology) for CO2 capture from power plants have been proposed and evaluated. Presently, the most advance and mature technique for CO2 capture is absorption technology using monoethanolamine (MEA), but this technology is considered cost and energy inefficient and the amine solvent (monoethanolamine) possesses low stability at elevated temperature [1]. The development of superior and advance materials with considerable lower energy and cost penalty is essential. Therefore one of the promising candidate is membrane technology and zeolite based membrane systems prove to handy and useful than the traditional processes [2] . Zeolite membranes have found tremendous uses in the industry for separation and purification application. For instance, hydroxy sodalite (SOD membranes are known to possess high chemical and thermal stability up to 450oC) [3]. However, commercial applications of zeolite based membranes are hampered by high cost of support and poor reproducibility. Moreover, zeolite membrane with zeolite coating on the support (i.e. thin-film supported zeolite membranes) are susceptible to abrasion and thermal shock at high temperature due to temperature mismatch caused by difference in thermal expansion of the zeolite material and the support, making them to lose selectivity very fast. On the contrary, nanocomposite architecture membranes obtained via pore-plugging hydrothermal synthesis protocol are more thermally stable and membrane defects are controlled [4, 5]. In this work, a nanocomposite architecture hydroxy sodalite membrane with zeolite crystals embedded within an α-alumina tube was synthesized using the pore-plugging hydrothermal synthesis technique and characterized. The as-prepared membrane was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM). The results obtained from these characterization techniques reveal that sodalite crystals were indeed grown within the porous structures of the support. In addition, the XRD analysis reveals the formation of sodalite crystals within the support. In addition, Small Angle X-Ray Scattering (SAXS) confirmed structural information such as particle size, shape and internal structure of SOD crystals. Since the average cage dimension of hydroxy sodalite is 0.265 nm, similar to the molecular size of an H2 (0.27 nm), the successfully synthesized membrane will be evaluated for removal of H2 from H2/CO2 mixture, a mixture that is obtained from pre-combustion after gasification in an Integrated Gasification Combined Cycle (IGCC) during power generation.

Topics

• porous
• nanocomposite
• impedance spectroscopy
• pore
• Carbon
• scanning electron microscopy
• x-ray diffraction
• combustion
• thermal expansion
• amine
• small angle x-ray scattering
• gasification