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Removal of Chromium from Liquid Waste by Gamma Aluminum Oxide (γ-Al2O3) Nanoparticles Synthesized using Citrate Sol–gel Method

Abstract Gamma Aluminum oxide (γ-Al2O3) nanoparticles of particle size less than 8 nm were synthesized from aluminum nitrate nonahydrate and citric acid fuel via a citrate sol-gel method. The prepared alumina products were characterized by means of X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FE-SEM) and High Resolution Transmission Electron Microscope (HR-TEM). Different phases of alumina like amorphous, γ- Al2O3 and α/γAl2O3 nanoparticles were obtained on changing the calcination temperature for the alumina samples. The adsorption properties of the active phase γ-Al2O3 for the removal of Cr(VI) from liquid waste were examined by batch adsorption study. The effect of different parameters such as initial pH value in solution, contact time and temperature on the adsorption performance of Cr (VI) onto γ-Al2O3 was studied . The adsorption process reached the equilibrium at 75 min and was found to be maximum at pH =3. The removal efficiency percent of Cr(VI) using γ-Al2O3 was increased with increasing temperature .The equilibrium adsorption was described with Langmuir model and the adsorption kinetics fits well pseudo- second-order model.