Adsorption Kinetic and Thermodynamic Studies of Silk Dyed with Sodium Copper Chlorophyllin.

In this study, silk was dyed into a bright green shade with a natural dye derivative, sodium copper chlorophyllin (SCC). Kinetics and thermodynamics of SCC adsorption on silk in dye bath with and without sodium chloride at different temperatures were investigated. The pseudo second-order kinetic model fitted experimental data well. Addition of sodium chloride increased SCC adsorption at equilibrium qe, increased the diffusion coefficient D and decreased the half dyeing time t1/2. The Langmuir isotherm agreed well with a high correlation coefficient (R2 > 0.99) for dyeing temperatures of 70, 80, and 90 °C with SCC concentration varying from 0.1 to 2.9 g/L. The thermodynamic parameters of SCC adsorption with and without sodium chloride showed significant difference. The adsorption affinity (−Δμ°) and enthalpy change (ΔH°) of SCC dye on silk indicated that the adsorption is a spontaneous and exothermic process. SCC could be a good candidate as a natural green dye for protein fibers. [ABSTRACT FROM AUTHOR]