Removal of Cu (II) Ions from Aqueous Solution Using Poly-Amidoxime Resin from Grafted Millet Husk Cellulose

Abstract

Poly-amidoxime ligand was synthesized on the cellulose isolated from millet husk through a graft copolymerization process for adsorption of Cu (II) ion from aqueous solution. The functional group, thermal degradation and morphology of the adsorbent were investigated by Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. The FTIR results showed that grafting was successful due to the presences of 2244 cm-1 for cyano group (CN) and also band at 1640 cm-1 and 1380 cm-1 that replaced 2244 cm-1 which successfully confirmed the synthesis of poly(amidoxime) functional group. The TGA showed two stages of thermal degradation 12 % weight loss observed in amidoxime at 2400C which is due degradation of amidoxime functional group then it reduces to 2% in second stage at 5300C which revealed the improved thermal stability of the material. The SEM image showed a clear morphology of the absorbent before adsorption and after adsorption. The Initial concentration, adsorbent dosage and contact time were taken as independent variables. The adsorption process was optimized by central composite design (CCD) in Response surface methodology (RSM). The predicted value is in good agreement with experimental value and also the ANOVA result showed that all the independent variables have significant impact with the adsorbent. The optimum condition achieved in the experiment was at initial concentration of 150 mg/L, adsorbent dosage of 0.3 g and contact time of 90 min for Cu2+ with percentage removal of 55.41 % predictably and 54.92 % experimentally.