The adsorption kinetics study of curcumin on a cotton fabric was investigated at three diff erent temperatures at neutral pH with 1 : 20 material liquid ratio and 1 g/L initial dye concentration. Pseudo fi rst-order and pseudo second-order kinetics were approached to experimental data and the adsorption kinetics of curcumin on cotton fi tted well with the pseudo second-order kinetic model. The activation energy was 71.96 kJ/ mol, whereas enthalpy and entropy were 68.99 kJ/mol and -59.7 J/mol K, respectively. Dye adsorption declined with increasing temperature, which suggests that the process is exothermic and the negative value of entropy indicates the presence of interaction between the adsorbent and adsorbate.

A kinetic study of curcumin on modal fabric was carried out using an initial dye concentration of 1 g/L at three diff erent temperatures, 70 °C, 85 °C and 100 °C, at pH 7 and an material to liquor ratio of 1:20. Pseudo fi rst-order and pseudo second-order kinetics were applied, and it was found that the adsorption kinetics of curcumin on modal fabric matched the pseudo second-order kinetic model. The activation energy was found to be equal to 71.14 kJ/mol, while the enthalpy and entropy of activation were 68.16 kJ/mol and -66.02 J/molK respectively.