Synthesis and Characterization of Aminated Copolymers of Polyacrylonitrile-Graft-Chitosan and Their Application for the Removal of Heavy Metals From Aqueous Solution

Abstract

Aminated copolymers of polyacrylonitrile-graft-chitosan (APANCS) were synthesized via the reaction of copolymers of polyacrylonitrile-graft-chitosan (PANg-CS) with diethylenetriamine in solution. Specifically, copolymers of PAN-g-CS have been obtained via a graft polymerization method using acrylonitrile (AN), chitosan (CS) and a free-radical initiating process with ceric ammonium nitrate (CAN) as initiator under air presence. Superficial structure of these copolymers was modified using amination reactions to introduce amine groups on its polymeric matrix. This polymer (APANCS) was applied in the removal of Pb 2+ , Cd 2+ and Zn 2+ ions in aqueous solutions. Samples of PAN-g-CS and APANCS were characterized by FT-IR spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, TGA, DSC and gravimetric analyses. Results of this study suggest that the amine groups of the structure of chitosan are involved in the grafting process onto the polymeric matrix of polyacrylonitrile. On the other hand, the adsorption capacities for heavy metal removal of this polymer were significantly improved using the chemical modification with amination reactions. Specifically, this polymeric material showed a maximum adsorption of 12.93, 2.27 and 2.10 mg/g at pH 5 for the removal of Pb 2+ , Cd 2+ and Zn 2+ ions, respectively.

Chitosan: Sources, Processing and Modification Techniques

“…Free radical initiated grafting is one of the mostly commonly used approaches. For example chitosan-graft-poly ( N -hydroxy ethyl acrylamide) using potassium persulphate initiator [ 223 ], polyacrylonitrile-g-chitosan (PA N -g-CS) in the presence of an initiator ceric ammonium nitrate [ 224 ], binary grafted chitosan with two monomers [acrylamide and (2-methacryloyloxyethyl) trimethyl ammonium chloride] via γ-radiation [ 225 ] graft copolymer of chitosan with poly [2-(acryloyloxy)ethyl trimethylammonium chloride] in the presence of potassium persulphate initiator [ 226 ], chitosan-g-polyaniline in the presence of APS [ 227 ]. Similarly, various crosslinking molecules such as simple phenolic compounds, glutaraldehyde, epichlorohydrin, ethylene glycol, diglycidyl ether and sodium tripolyphosphate etc.…”

Progress in Research of Chitosan Chemical Modification Technologies and Their Applications

“…The reagents used in free radical graft copolymerization are relatively safe and constitute commonly used graft copolymerization modification reaction systems. For example, Ja Dena-Aguilar et al [ 84 ] used acrylonitrile (AN), CS, and cerium ammonium nitrate (CAN) as initiators to synthesize polyacrylonitrile–graft–chitosan (PAN–g–CS) copolymer and then reacted it with diethylenetriamine to synthesize polyacrylonitrile–graft–chitosan (APANCS) aminated copolymer. The research shows that APANCS can better adsorb Pb 2+ , Cd 2+ , Zn 2+ , and other heavy metal ions in water, the synthetic route of which is shown in Figure 7 .…”

Copolymerization of acrylonitrile with a nitrogen-containing ester

“…Additionally, itaconic acid monoesters and monoamides, including 2-carbamoylmethacrylic acid, N-octyl-2-carbamoylmethacrylic acid, and 2-methoxycarbonylmethacrylic acid, were effectively employed in the thermal cyclization process of acrylonitrile copolymers [10]. Through a copolymerization reaction, aminated polyacrylonitrile-transplant-chitosan (APANCS) copolymers were synthesized using diethylene triamine and polyacrylonitrile-transplant-chitosan (PANg-CS) as precursors [11]. Specifically, PAN-g-CS copolymers were prepared through graft polymerization, utilizing acrylonitrile, chitosan, and a free radical initiation process with cerium ammonium nitrate (CAN) as the initiator, in the presence of air.…”