In order to understand the adsorption behavior of the dyeing of polyester fibres in supercritical carbon dioxide at 95 degrees C and 300 bar, the rate of dyeing and the equilibrium adsorption of a disperse dye, C.I. Disperse Orange 30 (DO30), have been investigated. The pseudo-first-order and pseudo-second-order kinetic models and particle diffusion model were used to describe the rate and the rate constants for the dyeing of polyester fibres were evaluated. The pseudo-second-order kinetic model fitted well to experimental data and the dyeing of polyester fibres was also followed by the particle diffusion model up to 60 min at 95 degrees C. The dyeing isotherm was obtained at 95 degrees C and 300 bar. The Freundlich model agreed very well with experimental data. The activation energy and adsorption enthalpy were calculated for adsorption of DO30 onto polyester fibres in supercritical carbon dioxide as well. (c) 2005 Elsevier B.V All rights reserved.