Kinetic and thermodynamic studies on gas adsorption behaviour of natural fibres

Gas adsorption properties of key natural fibres were investigated through monitoring the adsorption process of ammonia onto wool and cotton by time-resolved infrared spectroscopy. It was found that Langmuir isotherm model best described ammonia adsorption onto wool and cotton, indicating monolayer adsorption. The adsorption capacity of wool and cotton for ammonia was found to be 7.948 × 10⁻⁵mol g⁻¹ and 3.066 × 10⁻⁵mol g⁻¹, respectively. Adsorption diffusion was found to be the rate limiting step for wool in the initial adsorption stage, following the Dumwald–Wagner model. For cotton, adsorption reaction process was found to be the rate limiting step for the whole adsorption, following the pseudo-second-order model. The activation energy values of ammonia adsorption were calculated to be 26.50 kJ mol⁻¹ for wool and 30.43 kJ mol⁻¹ for cotton, which demonstrates that ammonia adsorption onto fibres requires energy. The study could promote developing textile products for odour control.