Chromium (VI) Biosorption Using Novel Biosorbents from Calotropis Gigantea

Abstract

Biosorption of heavy metals using plant based materials contributes a significant role in reducing environmental pollution. Here, we investigated removal of hexavalent chromium metal [Cr (VI)] from an aqueous solution by alkali treated novel biosorbent prepared from Calotropis gigantea (L.) Dryand. ex W.T. Aiton leaves and flower. Batch studies were conducted to examine the process parameters. The effect of pH, biomass dosage, initial metal ion concentration, contact time was evaluated keeping temperature and agitation speed constant. As much as 70% removal of Cr (VI) was observed with a leaf biomass dosage of 4 g/L at pH 2.0 and initial metal ion concentration of 1.0 ppm. Data obtained from the experiment were used to calculate the equilibrium data with two variable isothermal models. Freundlich and Temkin isotherm models suited the process for leaves and petals, respectively. Pseudo second order reaction suited in the kinetic study. The data obtained from the study suggests that biosorbents derived from C. gigantea has effective chromium biosorption capability. The results indicate that C. gigantea could be used as an efficient, cost effective and environmental friendly biosorbent for the treatment of chromium contaminated water bodies.