In this work the experimental and numerical techniques employed to estimate the diffusion coefficient of gold(III) in a macroporous particle of resin XAD-2 impregnated with triisobutyl phosphine sulfide (TIBPS) have been described. Batch and column experiments were performed in order to get the necessary experimental results to determine the effective diffusion coefficient, D e . In the studied initial metal concentration range (39.3-196 mg/dm 3 ), D e was found to increase with increasing the initial feed concentration from 1.28x10 - 8 to 6.40x10 - 8 m 2 /h.