Improvement of MOR zeolite membranes by using ion beam irradiation

Abstract

Improving water flux through a zeolite membrane is important in reducing the cost of manufacturing such membranes. Water flux through a mordenite (MOR) zeolite membrane was increased by 84% by treating it with a novel ion beam irradiation technique that maintained high water permselectivity (1200). Os ions were accelerated in a cyclotron at 490 MeV, and a fluence of 3.0 × 10¹¹ ions cm^-2 was employed for treatment. A calculation using SRIM 2012 showed that the Os ion tracks at 490 MeV should be passed through the MOR zeolite layer. In this study, ion tracks of approximately φ 8 nm were measured on the surface view of the transmission electron microscope (TEM) observations. The single gas permeation of H₂ and N₂ at room temperature was almost the same before and after irradiation treatment. The ion track pathways through the MOR layer were water permselective assuming that all the permeation change before and after irradiation was due to the ion track paths.