The retention properties of arsenic ions from an aqueous solution by water-soluble cationic polymers and cationic-anionic copolymers were investigated. Poly [(3-methacryloylamine)propyl]trimethylammonium chloride [P(ClMPTA)] and poly [(3-methacryloylamine)propyl]trimethylammonium chloride-co-acrylic acid [P(ClMPTA-co-AA] were synthesized by radical polymerization. The copolymers were prepared with feed mole ratios of ClMPTA to AA of 1 : 1, 1 : 2, and 2 : 1. The copolymer compositions were evaluated by FTIR spectroscopy, TG-DSC, and elemental analysis. The liquid-phase polymer-based retention (LPR) technique was used. This technique consists of retention of arsenate anions by the quaternary ammonium salt of a water-soluble polymer in a filtration membrane cell. It was shown that the polymers could bind H 2 AsO À 4 species from an aqueous solution more selectively at pHs of 6 and 8, than at a pH of 4. An increase in the polymer concentration was associated with increased retention capacity but not linearly. At the highest concentration the influence of pH was better observed. Investigation of copolymers showed the concerted action of polycations and polyanions on the ability to retain arsenic. At the lowest pH, the role of ionic strength of the media had a remarkable effect on the retention ability, independently of copolymer composition. At a pH of 6 a copolymer polycation/polyanion composition of 2 : 1 had the highest selective effect. At a pH of 8, a nonequimolar copolymer composition showed the same efficiency for the retention of arsenate species.

Arsenic is one of the most hazardous pollutants, and is present in water, mainly, as As(V) and As(III), and in its inorganic hydrolysis species. Great efforts have been made to develop effective removal techniques. One alternative is the use of water‐soluble polymers containing functional groups to remove these toxic species. This paper presents the synthesis and characterization (FT‐IR and 1H NMR spectroscopy, as well as thermogravimetry TG‐DSC) of two cationic water‐soluble polymers containing tetra alkylammonium groups, poly[2‐(acryloyloxy)ethyl]trimethylammonium chloride, and poly[2‐acryloyloxy)ethyl]trimethylammonium methyl sulfate (P(SAETA)). The arsenate retention properties were investigated using the liquid‐phase polymer‐based retention technique. The polymer structure and the exchangeable anions' nature have been shown to be two important variables in the removal efficiency of arsenate anions from aqueous solutions. Both investigated polymers were found to efficiently remove HAsO42− species from an aqueous media, with pH ranging from 6 to 8. The exchange of methyl sulfate for the chloride anion on P(SAETA) improved arsenate ion retention ability. The modification of ionic strength by Na2SO4 addition induced a significant decrease in the cationic polymer's arsenate retention properties. The polymers' retention properties were not studied using real samples. POLYM. ENG. SCI., 47:1256–1261, 2007. © 2007 Society of Plastics Engineers

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Different cationic water-soluble polymers with (R) 4 N 1 X À groups and pyridinium groups were prepared, and their arsenate retention performance was investigated with the liquid-phase polymer-based retention technique. Poly [3-(methacryloylamino)propyl]trimethylammonium chloride, poly[2-(acryloyloxy)ethyl]trimethylammonium chloride, poly(ar-vinylbenzyl)trimethylammonium chloride, poly[2-(acryloyloxy)ethyl]trimethylammonium methyl sulfate, poly(4-vinyl-1-methyl pyridinium)bromide, and poly [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide were prepared. The synthesis of the polymers by solution radical polymerization produced a yield higher than 77%. Structural analyses were performed with Fourier transform infrared and 1 H-NMR spectroscopy and thermogravimetry/differential scanning calorimetry. Commercial poly(4-vinyl-1-methyl pyridinium)bromide and poly(ar-vinylbenzyl)trimethylammonium chloride were also used. The liquid-phase polymer-based retention technique was employed to study the retention of arsenate species. The polymer structure and exchange groups, such as methyl sulfate, chloride, bromide, and hydroxide, presented different properties for removing arsenate anions from aqueous solutions. The type of voluminous quaternary ammonium group present influenced arsenic retention. All the polymers could bind HAsO 4 2À species from an aqueous solution more selectively at pHs 8 and 6 than at pH 4.