The addn. of inert particles of lighter d. and smaller diam. increases considerably the mass transfer coeff. in comparison to that of mono-component active particles at the same liq. velocity. This effect was applied to elimination of Cu ions by adsorption on a chelating resin. The intensification of the film mass transfer coeff. in binary system leads to a 15% increase of the usable adsorbent efficiency. [on SciFinder (R)]