Polymer‐based metal adsorbents via graft copolymerization of polyvinyl alcohol with diaminomaleonitrile: A green chemistry approach

Abstract

Synthesis, characterization, and amidoximation of diaminomaleonitrile‐functionalized polyvinyl alcohol (PVA) grafts were studied. Ceric ammonium nitrate (CAN) was used as an initiator in an aqueous nitric acid medium under N2 atmosphere. Optimum conditions for grafting were as follows: monomer concentration [DAMN] = 1.4M, [CAN] = 16 × 10−2 mol/L, T = 50°C, and t = 2 h. Water uptake of the PVA graft films increased with the increase of grafting yield. The imparted cyano group of the grafted PVA polymer chains (with degree of grafting up to 136%) was converted into amidoxime group by the reaction with hydroxylamine hydrochloride. The grafted polymers were characterized by FTIR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. The grafted PVA films are more thermally stable than the ungrafted PVA membrane, because the grafted membrane showed a single degradation pattern despite having two components. A decrease in Tg values is observed as the grafting yield of copolymers increases indicating the incorporation of polydiaminomaleonitrile chains in amorphous copolymers with higher thermal stability. The prepared amidoximated DAMN136‐g‐PVA was investigated for its properties in removing heavy toxic metals, such as Pb2+, Cd2+, Zn2+, Fe3+, Cu2+, Ni2+, and Co2+ from water. The amidoximated film is characterized by a considerably greater binding ability with respect to heavy metals. The nature of the metal ion also has great importance in the amount binding to the polymeric material. The kinetics of the sorption/desorption process for Co2+, Ni2+, and Zn2+ were investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Solid state grafting copolymerization of acrylamide onto poly(vinyl alcohol) initiated by redox system

“…Both the higher beginning temperature and less total weight loss means that the grafted PVA are more thermally stable than the original PVA. This is consistent with observations of Demchenko's group 30 and Abdel‐Razik's group . The main reason for this has been claimed to be the result of cooperative hydrogen bonding between the main and graft chains and then cross‐linking before the thermal decomposition …”

Preparation and adsorption behaviors of ethylene diamine tetraacetic acid modified zwitterionic hybrid materials

“…[1][2][3][4] Generally, these toxic heavy-metal ions cannot be effectively biodegraded in nature and are easily accumulated in the human body and other organisms. It has been reported 5 that an excess intake of toxic heavy metals will induce various diseases and health problems in humans.…”

“…Water pollution caused by toxic heavy‐metal ions, such as Cu 2+ , Pb 2+ , and Cd 2+ , from aqueous solution and industrial wastewater has become a hot topic and is challenging researchers and engineers . Generally, these toxic heavy‐metal ions cannot be effectively biodegraded in nature and are easily accumulated in the human body and other organisms.…”