Biosorption of hexavalent chromium using tamarind ( Tamarindus indica  ) fruit shell-a comparative study

The adsorption of chromium (VI) ions from aqueous solutions has been investigated on crude tamarind fruit shell, HCl treated and Oxalic acid treated shells at room temperatures. The biosorbents are characterized by FT-IR, EDXRF and porosimetry. The biosorption experiments are conducted through batch system. The influence of different experimental parameters such as pH, effect of initial metal ion concentration and effect of dosage of adsorbent on biosorption are evaluated. The adsorption followed first order kinetics. The data are fitted well to Langmuir and Freundlich isotherm models. A comparison is drawn on the extent of biosorption between untreated and treated forms of the tamarind shells. Due to their outstanding adsorption capacities, tamarind shells are excellent sorbents for the removal of chromium ions.

Keywords
biosorption, chromium (VI), pre-treatment, Tamarindus indica fruit shell.