To determine effective surface self-diffusion coefficients of CO2 within type 13X zeolite particles, at various temperatures (25-70 degrees C), inverse analyses of observed CO2-uptake curves were successfully performed. The obtained effective surface self-diffusion coefficients increase with both the amount adsorbed and the temperature and ranged from 7.8 x 10(-10) to 1.95 x 10(-9) m(2)/s under the present experimental conditions. (c) 2004 Elsevier Ltd. All rights reserved.