Two‐resistance mass transfer model for the adsorption of various dyestuffs onto chitin

The kinetics of the adsorption of various dyestuffs onto chitin have been studied. The dyestuffs used are Neoland Blue 2G, Eriochrome Flavine A, and Solophenyl Brown 3RL and a number of process variables were considered, such as adsorbent mass and dye concentration. The mass transfer model is based on the assumption of a pseudoirreversible isotherm and two resistances to mass transfer. These are external mass transfer and internal pore diffusion mass transfer. The rate of adsorption of dyestuffs onto chitin can thus be described by an external mass transfer coefficient and a pore diffusion coefficient. The external mass transfer coefficients are 5.0 × 10⁻⁵, 5.0 × 10⁻⁵, and 1.0 × 10⁻⁵ m·s⁻¹ and the pore diffusivities are 3.0 × 10⁻¹⁰ and 4.0 × 10⁻¹¹ m²·s⁻¹ for Neolan Blue 2G, Eriochrome Flavine A, and Solophenyl Brown 3RL, respectively.