Removal of hexavalent chromium Cr (VI) using activated carbon prepared from mango kernel activated with H3PO4

Abstract

The present work reported the adsorption of Cr (VI) from aqueous solutions on activated carbon prepared from mango kernel, a seasonal waste from mango fruits. Kernels from dried mango fruit shells were taken out and pulverized in a micro-pulverizing mill. The powder thus obtained was activated with 40% H3PO4 and carbonized at 600 °C for 1 hour in an inert atmosphere. Physico-chemical characteristics such as elemental composition, surface area, functional groups and surface morphology of the activated carbon were analyzed using elemental analyzer, BET surface area analyzer, FTIR spectroscopy and SEM analysis respectively. Batch adsorption experiments were performed to investigate the effects of Cr (VI) concentration, carbon dose, pH, rate of agitation, time and temperature. The maximum adsorption capacity of Cr(VI) was found to be 7.8 mg g−1 at pH 2 and temperature 35 °C. The Langmuir adsorption isotherm best represented the equilibrium data and a pseudo-second order relation represented the adsorption kinetics.