Extraction of hexavalent chromium from polluted waters using bioadsorbents derived from leaves of Croton tiglium and Cassia occidentalis plants

摘要

The adsorption abilities of bio-sorbents derived from plant materials towards polluting ions is one of the highly thrust areas of pollution control research and is being intensively probed in developing simple, efficient and ecofriendly methodologies in the removal of hazardous ions. In the present work, bio-adsorbents derived from leaves of Croton tiglium and Cassia occidentalis, have been investigated for their adsorption nature towards Chromium (VI) ions. The effects of various physicochemical parameters viz., equilibration time, pH and sorbent concentration, on the extraction of Chromium (VI) have been studied and optimized. Common cation ions (in tenfold excess) normally present in natural waters, viz., Ca2+, Mg2+, Cu2, Zn2+, Ni2+ and Fe2+ are found to have synergistic effect in increasing the % removal of Chromium. Anions like Phosphate, SO4 2- and Carbonate are found to be interfering in the order: PO4 3- SO4 2- CO3 2-. The monovalent ions: NO3-, Chloride, and Fluoride are found to have marginal interference. More than 90.0% extraction of Chromium (VI) is observed with the developed active sorbents. The methodologies developed are applied to real samples of industrial effluents and polluted lakes and found be remarkably successful.