Removal of Hexavalent Chromium Ions from Aqeous Medium using Chitosan Magnetic Nanocomposite Modified with Hexamine

Abstract

This work integrates nanotechnology, adsorption, and magnetic separation to remove chromium (Cr) pollutant from industrial wastewater using magnetic nanoparticles. The magnetic nanocomposite consists of chitosan biopolymer and iron (Fe₃O₄) magnetic nanoparticles. The Fe₃O₄ magnetic nanoparticles were prepared by chemical co-precipitation technique and the chitosan magnetic nanocomposite (CMNC) was prepared by Ex situ process. Moreover, anoval amination of CMNC with hexamine  to get functionalized CMNC was performed to remove Cr (VI) in wider range of pH. The prepared Fe₃O₄ magnetic nanoparticles, CMNC and functionalized CMNC were characterized using different analytical techniques, XRD, FTIR, AFM, SEM, EDX and TGA. Batch adsorption was employed to determine the effects of pH. The adsorption results show that the functionalized CMNC possessed high activity for Cr (VI) removal in any condition of acidic, neutral and basic solutions with the percentage sorption of chromium reached to 91.7%. Sorption isotherms were fitted with the Langmuir, Freundlich and Temkin models, it was found that the Freundlich isotherm model have the best fit with R²=0.998 with functionalized CMNC. The kinetic data of Cr (VI) sorption with functionalized CMNC were fitted well with the pseudo-second order kinetic model. The reuse of the functionalized CMNC indicates that the adsorbent material is more than 80% adsorption capacity after five regeneration cycles. The results of this work shown that functionalized CMNC is a potential adsorbent to removal of Cr (VI) contaminated in a wider range of pH.