Novel hydrogels based on itaconic acid and citraconic acid: Synthesis, metal ion binding, and swelling behavior

Abstract

Several copolymer hydrogels were prepared from radical copolymerization of 2-hydroxypropyl methacrylate (HPMA) with itaconic acid (IA) and also with citraconic acid (CA) by using different feed ratios. The copolymers were characterized by FTIR, 1 H-NMR, and 13 C-NMR spectroscopy as well as by thermal analysis. The swelling process of the different hydrogels immersed in water at different pH has been studied, and also the swelling of the hydrogels loaded with metal ions (Pb 2þ , Cd 2þ ) was investigated. The metal-binding properties were studied by using the liquid-phase polymer-based retention technique, including studies on the influence of pH on the binding process. The efficiency of these hydrogels for the recovery of metal ions in solution was determined by atomic absorption spectroscopic analysis. The thermal characteristics of these copolymers were studied by using differential scanning calorimetry and thermogravimetric analysis in nitrogen atmosphere. Accordingly, the gels loaded with metal ions showed a slight increase of the thermal decomposition temperature when compared with the pristine gels. The copolymer gel HPMA-co-CA showed a single glass transition temperature, whereas for the copolymer systems, HPMA-co-IA, only the copolymers loaded with Cd 2þ ions showed a glass transition temperature. The morphology of film produced from the copolymers was investigated by scanning electron microscopy, revealing generally smooth surfaces.

Heavy and toxic metal ion removal by a novel polymeric ion-exchanger: synthesis, characterization, kinetics and equilibrium studies

“…The separation of heavy and toxic metal ions from industrial effluents is of great interest because of their harmful nature and ability to be retained in living systems. This gives special emphasis to the recovery of these harmful ions from water using selective functional polymeric sorbents . The commonly used technologies for removing heavy metal ions from effluents include chemical precipitation, coagulation, liquid–liquid extraction, ion exchange, etc.…”

Separation of metal ions by the influence of a cation-exchange terpolymer involving 2-amino-6-nitrobenzothiazole-ethylenediamine-formaldehyde

“…Ion exchange has been widely adopted for treating heavy metal‐containing wastewater and most of the ion‐exchangers currently being used are commercially mass‐produced organic resins. Ion‐exchange properties depend on the chelating resins, fast kinetics of metal ion uptake, high mechanical strength, durability, physical and chemical properties such as type and structure of functional groups introduced into the polymer matrix, degree of crosslinking and swelling, as well as sorption conditions including the solution pH, presence of electrolyte during shaking, contact time, metal ion concentration and presence of interfering ions …”

Enhanced and selective adsorption of heavy metal ions on ion-imprinted simultaneous interpenetrating network hydrogels

“…Major attractions of hydrogels are their potential for regeneration after uptake of the contaminants and easy applicability. [5][6][7][8][9] Due to the poor mechanical strength of hydrogels, interpenetrating polymer network (IPN) technique, which can combine the properties and structures of several polymeric materials into a new material, is usually employed to improve the mechanical properties. [10,11] From a synthetic standpoint, IPN comes in two varieties, sequential IPN and simultaneous IPN.…”