The preparation and gas separation properties of zeolite/carbon hybrid membranes

Zeolite/carbon hybrid membranes with enhanced gas permeability were prepared by the incorporation of zeolites Y, β, or ZSM-5 into the precursor of polyamic acid and carbonization at high temperature. The effects of physical and chemical properties of zeolites and the preparation parameters, involving the agglomeration size and crystal diameter of zeolites, content and carbonization temperature, on the related gas separation performances were investigated. Results indicate that embedding the zeolites into carbon membrane can greatly increase the gas permeability of carbon membranes without losing the selectivity obviously. The properties of embedded zeolites and the preparation parameters greatly affect the gas separation performances of derived zeolite/carbon hybrid membranes. The gas permeability and selectivity of derived hybrid carbon membranes can be tuned by optimizing the embedded zeolite properties such as the agglomeration size and crystal diameter, and the preparation parameters such as the zeolite content and carbonization temperature. The effects of incorporating the zeolite into carbon membrane on enhancing the gas permeability might be attributed to the intactly ordered inner pore channels of embedded zeolite, which provides rapid and continuous diffusive routes for gas molecules and interfaced pores formed between the embedded zeolite and carbon matrix, which create new channels for gas diffusion in carbon membranes.