Biosorptive removal of cobalt (II) ions from aqueous solution by Amaranthus hydridus L. stalk wastes

Abstract

The objective of this study was to investigate the possibility of using Amaranthus hybridus L. stalk as an alternative to high cost commercial adsorbent materials for the removal of Co (II) from aqueous solution. The experiment was carried out by batch method at 33°C. The influence of pH, contact time and initial metal ion concentration were evaluated. It was observed that pH had marked effect on the Co (II) uptake. The optimum contact time between the adsorbent and the adsorbate was found to be 90 min. Maximum adsorption was obtained at pH 5. Freundlich models were used to correlate equilibrium data on sorption of Co (II) ion at 33°C and pH 5, and different coefficients were calculated. The data generated, fitted well with Freundlich adsorption model. The biomass was successfully used for removal of cobalt (II) ion from synthetic aqueous solution and the technique appears industrially applicable and viable.

Key words: Biosorption, cobalt, aqueous solution, Amaranthus hydrides.