Adsorptive Removal of Hexavalent Chromium using Synthetic Goethite Nanoparticles

Abstract

This study investigated the adsorptive removal of hexavalent chromium from aqueous solution using synthetic goethite nanoparticle. The goethite particle (α-FeOOH) was synthesized and characterized usingFourier Transform Infrared, Scanning Electron Microscopy, Transmission Electron microscopy and Malvern nanosizer.Broad peaks around 3142 and 3404 cm^-1were attributed to O-H stretching vibration of the hydroxyl group and the strong intensities at 634 cm^-1, 796 cm^-1 and 893cm^-1 were attributed to Fe-OHstretching frequencies. The physico-chemical parameters including pH, colour, point of zero charge (pzc) and surface area were determined. Batch adsorptionexperiments were carried out on hexavalent chromium Cr (VI)as a function of pH, contact time, initial concentration of the adsorbateand temperature of the solution. The maximum concentration adsorbed was 20 mg/l at a maximum pH of 2. The maximum adsorption was achieved within 120 minutes and adsorption was observed to increase with increase in temperature. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption was spontaneous in nature, and endothermic. The equilibrium data better fitted the Freundlich isotherm model.

Keywords: Adsorption, Goethite, Hexavalent Chromium, Kinetics, Thermodynamic