Two-resistance mass transfer models for the adsorption of dyestuffs from aqueous solutions using activated carbon

The adsorption of telon blue (acid blue 25) dye and deorlene yellow (basic yellow) dye on to carbon has been studied. A two-resistance mass transfer model has been developed based on film resistance and homogeneous solid phase diffusion. The model may be applied over a wider range of operating conditions than previous models since it has more extensive analytical components. The variables investigated were initial dye concentration and solid: liquid ratio, and the experimental and theoretical results were in good agreement. The adsorption of telon blue on to carbon has been described using an external mass transfer coefficient of 2.0 × 10⁻³ cm s⁻¹ and a homogeneous solid phase diffusion coefficient of 2.0 × 10⁻⁹ cm² s⁻¹. The adsorption of deorlene yellow has been described using an external mass transfer coefficient of 1.0 × 10⁻³ cm s⁻¹ and a homogeneous solid phase diffusion coefficient of 3.0 × 10⁻¹⁰ cm² s⁻¹.