Use of activated carbons prepared from sawdust and rice-husk for adsorption of acid dyes: a case study of Acid Yellow 36

Activated carbons, prepared from low-cost mahogany sawdust and rice husk have been utilized as the adsorbents for the removal of acid dyes from aqueous solution. An acid dye, Acid Yellow 36 has been used as the adsorbate. Results show that a pH value of 3 is favourable for the adsorption of acid dye. The isothermal data could be well described by the Langmuir and Freundlich equations. Kinetic parameters of adsorption such as the Langergren pseudo-first-order constant and the intraparticle diffusion rate constant were determined. For the present adsorption process, intraparticle diffusion of dye molecule within the particle has been identified to be rate limiting. The adsorption capacities of sawdust carbon (SDC) and rice husk carbon (RHC) were found to be 183.8 mg and 86.9 mg per g of the adsorbent respectively. The results indicate that SDC and RHC could be employed as low-cost alternatives to commercial activated carbon in wastewater treatment for the removal of acid dyes. (C) 2003 Elsevier Science Ltd. All rights reserved.