Removal of reactive dye from aqueous solutions by adsorption onto activated carbons prepared from sugarcane bagasse pith

Bagasse pith, which is the main waste from sugarcane industry in Egypt, has been used as a raw material for the preparation of different activated carbons. Activated carbons were prepared from bagasse pith by chemical activation with 28% H3PO4 (AC1), 50% ZnCl2 (AC2) followed by pyrolysis at 600°C and by physical activation at 600°C in absence of air (AC3). Different activated carbons have been used for the removal of reactive orange (RO) dye from aqueous solutions. Batch adsorption experiments were performed as a function of initial dye concentration, contact time, adsorbent dose and pH. Adsorption data were modeled using the Langmuir and Freundlich adsorption isotherms. Adsorption kinetic data were tested using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Kinetic studies showed that the adsorption followed pseudo-second-order reaction with regard to the intraparticle diffusion rate.

AC1 AC2 AC3 1.0 Time1/2 Fig. 9. (a) Intraparticle and pore diffusion for adsorption of RO onto activated carbons at pH 1 dose of adsorbent = 5 g L−1 and different dye concentration, (a) 20 mg L−1, (b) 50 mg L−1 and (c) 80 mg L−1.