Amidoximated Sunflower Stalks (ASFS) as a New Adsorbent for Removal of Cu (II) from Aqueous Solution

A sunflower stalk graft copolymer was prepared by the reaction of ground sunflower stalks (SFS) with acrylonitrile (AN) in aqueous solution initiated by KMnO4-citric acid (CA) system. It has been shown that the grafting parameters, such as concentration of KMnO4, AN, and CA, have a significant effect on graft copolymerization. The temperature as well as the duration time of the reaction were studied and also showed a significant effect on the graft copolymerization reaction. The possible reaction was deduced by estimation of nitrogen content. Amidoximation of the grafted stalks was performed by the reaction of grafted SFS with hydroxylamine hydrochloride in alkaline medium to obtain amidoximated sunflower stalks (ASFS). The obtained amidoximated product was detected by FT-IR spectra. The effects of pH and concentration of the adsorbent, ASFS, on adsorption of Cu (II) were studied. The study shows that the ASFS was effectively used in adsorption of Cu (II) ions from aqueous solution. The adsorption data obeyed Langmuir and Freundlich isotherms.