Removal of Hexavalent Chromium from Aqueous Solution using Magnetic Sepiolite Nano-composite as an Adsorbent

Abstract

Magnetic nano-composite (MNCs) samples were prepared by co-precipitation method and characterized by XRD, SEM, nitrogen adsorption–desorption. The prepared MNCs evaluated for removal of hexavalent chromium Cr(VI) from its solutions. The adsorption experiments performed by bath method and the effects of solution pH, Cr(VI) concentration and contact time were studied. The adsorption capacity of the MNCs was affected significantly by pH of the Cr(VI) solution and based on the degree of magnetite. The results showed that the adsorption of Cr(VI) decreased with the increase of pH. The highest removal efficiency was achieved with the composite having the highest content of magnetite. The optimum contact time for maximum adsorption capacity was determined to be 480 min. The obtained adsorption data analyzed by the Langmuir, Freundlich and Sips isotherm models. The equilibrium data fitted well to the Sips model at a solution pH value of 2.0. The kinetic study showed the adsorption process followed pseudo-second-order kinetic. The prepared nano-composite materials can be used to remove Cr(VI) from water and industrial wastewater.