This paper presents the results of an experimental study of mass transfer at gas drying by adsorption on composite materials, in fixed bed. In the experimental investigations were employed two composite adsorbent materials, MCS1 and MCS2, composed of spherical silica gel grains impregnated with CaCl(2) and wet air (relative humidity: 69% and 97.75%) at several values of temperature (300, 311, 322 K) and air flow rate (0.3, 0.6, 0.9, 1.2, 1.5 m(3).h(-1)). There were also experimentally determined as a function of time the variation of water concentration in solid phase and water concentration and temperature at the column exit in gas, phase. Based on these data the formal adsorption rate of water vapor, v(a), and apparent mass transfer coefficient, K, were determined as a function of time and it was studied the influence of temperature, air flow velocity and CaCl(2) concentration in adsorbent over v(a) and K.