Anisotropic composites based on heterogeneous ion-exchange membranes MK-40 and polyaniline have been prepared in a constant electric field. The diffusion and electric conduction properties of these materials in sulfuric acid solutions have been studied, and the diffusion permeability of the composites has been shown to decrease compared to the base membrane, with the conductivity remaining relatively unchanged. Investigation of mass transport of ions through the composite membranes during electrodialytic demineralization of sulfuric acid solutions has revealed that the performance of such materials in high-intensity current modes is higher than that of the base MK-40 membranes. In particular, the energy consumption for demineralization of sulfuric acid solutions is reduced by 40-60% and the current efficiency increases approximately twofold under certain conditions. The mass transfer and energy characteristics of the electrodialysis process have been found to depend on the orientation of the modified layer of the composite membranes with respect to the counterion flow.