Study of NaY Zeolite Modified With 3 Alkanolamines and (3-aminopropyl) Trimethoxysilane (APTMS) to be Used in the Production of Mixed Matrix Membranes (MMM's) for CH4/CO2 and CH4/H2S Gas Mixtures Separation

Abstract

NaY zeolite was physical and chemically modified using 3 different alkanolamines: monoethanolamine (MEA), diethanolamine (DEA) and methyl diethanolamine (MDEA), which are commonly used in adsorption of acid gases during the natural gas sweetening process. Additionally, chemical modification of NaY zeolite was performed with (3-aminopropyl) trimethoxysilane (APTMS) usually utilized for grafting of silica surfaces with amine groups, which enhance the chemical affinity with acid gases such as: CO₂ and H₂S.

Surface and structural properties of the modified NaY zeolite were determined by X-Ray Diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Transmission Electron Microscopy (STEM) and N₂ Porosimetry adsorption-desorption. The results showed the introduction of the alkanolamines into the zeolite NaY pores even after several methanol washing steps. On the other hand, the chemically modified NaY Zeolite showed the amine grafting without any microstructural modification in the zeolite surface. Both methodologies (physical and chemical modifications) could increase the affinity of the particles toward polar molecules such as CO₂ and H₂S, improving the performance of these materials in Mixed Matrix Membranes (MMM’s) intended for separation of acid gases.