The Usage of Modified Chitosan for the Removal of Hexavalent Chromium from Waste Water

Abstract

This study presents the results of chromate adsorption upon chitosan modified with thiourea, glutaraldehyde. Firstly modified chitosan was synthesized by using thiourea, glutaraldehyde and chitosan at different molar ratios and adsorption capacities were compared to the original chitosan. The modified chitosan showed higher Cr (VI) retention performance than the original chitosan. While the original chitosan had a percent removal of 32% at an initial concentration of 50 ppm, the percentage of chitosan removal improved to 99.9%. Kinetic and thermodynamic constants are determined at appropriate ambient conditions and adsorption is defined by appropriate adsorption isotherms. Langmuir isotherms were found to be suitable for characterizing the adsorption of chitosan with the modified Cr (VI) ions. Under appropriate experimental conditions, percentages of removal in Cr (VI) removal studies by adsorption using modified chitosan reached 99% and adsorption capacity of 442 mg/g was observed.Characterization of the modified chitosan and original chitosan were characterized by FTIR (Fourier Transform Infrared Spectroscopy), TGA (Thermal Gravimetric Analysis), XRD (X-ray Diffraction) and DSC (Differential Scanning Calorimetry) .