Kinetics and diffusion processes in colour removal from effluent using wood as an adsorbent

Abstract

The rates of adsorption of a basic dye, Astrazone Blue, and an acidic dye, Telon Blue, on wood have been studied. The rate controlling step is mainly intraparticle diffusion, although a small resistance due to a boundary layer is experienced. The activation energies for the adsorption of Astrazone Blue and Telon Blue on wood are 16.8 kJ mol−1 and 9.6 kJ mol−1, respectively. The diffusion coefficients vary from 6×10−13 cm 2 s−1 to 18×10−13 cm 2 s−1 for Astrazone Blue at 18°C and from 3 × 10−13 cm 2 s−1 to 8 × 10−13 cm 2 s−1 for Telon Blue at 18°C. The variation in diffusivities is attributed to boundary layer effects.