Removal of Cu(II) ions from aqueous water by l -arginine modifying magnetic chitosan

Abstract

A new adsorbent l-Arg-CS/Fe3O4 was prepared by l-arginine modifying magnetic chitosan for the removal of Cu(II) ions from aqueous solution. The compositions of l-Arg-CS/Fe3O4 were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis and thermogravimetric (TG) analysis, respectively. The surface morphology, particle size and specific surface area were measured on scanning electron microscope (SEM) and micromeritics gas adsorption surface analyzer. The adsorption behavior of l-Arg-CS/Fe3O4 for Cu(II) were investigated as a function of pH, contact time and initial Cu(II) concentration. The maximum adsorption capacity for Cu(II) was 2.13 mmol g−1 at the optimized adsorption conditions, which were pH = 5.5, t = 13 min, C0 = 4.0 mmol L−1. The adsorption behavior was evaluated by the analysis of adsorption kinetics. Freundlich and Langmuir isotherm models were used to estimate the adsorption mode. l-Arg-CS/Fe3O4 exhibited high adsorption capability after five regeneration cycles. The adsorption and desorption mechanisms were discussed. The results show that l-Arg-CS/Fe3O4 is a promising adsorbent for removal of Cu(II) from aqueous solutions.