Removal of malachite green dye from aqueous solution by adsorption using agro-industry waste:: a case study of Prosopis cineraria

Adsorbents prepared from Prosopis Cineraria sawdust-an agro-industry waste-were successfully used to remove the malachite green from an aqueous solution in a batch reactor. The adsorbents included formaldehyde-treated sawdust (PCSD) and sulphuric acid-treated sawdust (PCSDC). The effects of adsorbent surface change, initial pH, initial dye concentration, adsorbent mass and contact time on dye removal have been determined. Similar experiments were carried out with commercially available coconut based carbon (GAC) to evaluate the performance of PCSD and PCSDC. The adsorption efficiency of different adsorbents was in the order GAC>PCSDC>PCSD. Kinetic parameters of adsorption such as the Lagergren pseudo-first-order constant and the intra particle diffusion were determined. An initial pH of the solution in the range 6-10 was favourable for the malachite green removal for both the adsorbents. These experimental studies have indicated that PCSD and PCSDC could be employed as low-cost alternatives in wastewater treatment for the removal of dyes. (C) 2003 Elsevier Ltd. All rights reserved.