Ethylcellulose (EC), linear polyimide (LPI) or hyperbranched polyimide (HBPI) and magnetic neodymium powder MQP-14-12 have been used for the preparation of magnetic mixed matrix membranes (MMMs). Permeability diffusion and sorption coefficients of O-2, N-2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the time lag method based on dynamic experiments in a constant pressure system. The effect of magnetic powder particles on the gas transport properties of MMMs was studied. The results showed that the membrane permeation properties were improved with the magnetic neodymium particle filling. It was observed that the magnetic ethylcellulose and polyimide membranes showed higher gas permeability, while their permselectivity and solubility were rather maintained or slightly increased. The results also showed that the magnetic powder addition enhanced significantly gas diffusivity in EC and polyimide membranes. (C) 2013 Elsevier B.V. All rights reserved.