Original Articles: 2011 Vol: 3 Issue: 1
Sorption of copper and zinc using fibres of Cocos nucifera
Fibres of Cocos nucifera (coir) is a low cost biosorbent that has been used for the removal of zinc and copper metal ions from aqueous solutions. Batch sorption experiments were carried out with Zn (II) and Cu (II) to quantify the sorption kinetics, the pH dependence of the sorption, sorption isotherms at pH 3.0 and pH 5.6, and desorption. Ungrounded and unmodified coir was used and the metal concentrations ranged between 0 and 0.015 mM (1000 μgL-1) for Zn (II) and 0 and 9.7 10-4 mM (200 μgL-1) for Cu (II). The optimum pH was 4.5 (91%) for zinc and 3.5 (97%) for Copper removal. Copper had a higher sorption affinity than Zinc and the affinity was higher at pH 5.6 than at pH 3.0. The sorption data fitted well the Freundlich model in the concentration range tested. Desorption experiments demonstrated that less than 1% and 13% of the sorbed Copper and Zinc, respectively, could be desorbed at pH 5.6 during 2 h.