Abstract
Silicalite-1 crystals with a modified shape have been synthesized using organic polycations (dimer and trimer TPA) as zeolite shape modifiers to enhance the relative growth rate along the b-axis (straight channels). The crystal surface microstructure and subsequent identification of the crystallographic faces has been analyzed using High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED). The modified morphology enabled the fabrication of b-oriented silicalite-1 membranes that show the best performance reported up to now in xylene separation. A method based on growth of an oriented seed layer to a well-packed film is also reported here.