Here we present a mathematical model of coupled heat and mass transfer in the course of water adsorption on a single adsorbent grain, which is in thermal contact with an isothermal metal plate. Adsorption is caused by a large jump of vapour pressure over the grain. The radial profiles of the grain temperature and the water concentrations in the adsorbed and gas phases were calculated as a function of time. Strong interrelationship between the shapes of the water sorption isotherm and the radial uptake profile was revealed. The best fit to the experimental data of [B. Dawoud, Yu. I. Aristov, Experimental study on the kinetics of water vapour sorption on selective water sorbents, silica-gels and alumina under typical operating conditions of sorption heat pumps, Int. J. Heat Mass Transfer 46 (2) (2003) 273-281] corresponds to the water diffusivity D-e = 6.0 x 10(-6) m(2)/s and the coefficient of the heat transfer alpha(p) = 70 W/(m(2) K) which are larger than those measured in quasi-equilibrium experiments. (c) 2008 Elsevier Ltd. All rights reserved.