Adsorption of chromium (vi) from aqueous solution using bio-sorbent

Environment is deteriorating day to day due to the industrial pollution, toxic chemicals etc. which lead to the accumulation of contaminants inclusive of heavy metals in waste water. The water polluted by industrial effluents disturbs its normal use for agriculture and aquatic/terrestrial life. In view of toxicity, non-biodegradability and persistent nature their removal becomes an absolute necessity. Hexavalent chromium metal ion is one of the major pollutants in the environment and is frequently present in waste water released from various industrial units. Several conventional physical and chemical treatment techniques are reported in the literature for the removal of hexavalent chromium. However these processes are not only expensive and energy intensive, but also lead to the production of harmful by products. The present research article reports, the potential application of self prepared activated carbon derived from the bark of Tamarindus indica followed by chitosan (deacetylated derivative of chitin) coating as an adsorbent for removal of hexavalent chromium from aqueous solution. The batch experiments were carried out to investigate the effect of significant process parameters such as pH, contact time, adsorbent dosage and initial Cr(VI) ion concentration. The maximum adsorption of Cr(VI) on bio-sorbent was found at pH 4.5. The removal of hexavalent chromium from aqueous solution increases with increase in contact time and adsorbents dose. The maximum removal capacity for Cr(VI) have been noticed to be 96.50%. This investigation verifies that the chitosan coated activated carbon derived from Tamarindus indica bark (a bio-sorbent) can be used as a valuable adsorbent material for removal of hexavalent chromium from contaminated water and may contribute in pollution control.