Retention properties of arsenate anions of water‐soluble polymers by a liquid‐phase polymer‐based retention technique

Abstract

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 extraction from aqueous solution: Electrochemical oxidation combined with ultrafiltration membranes and water-soluble polymers

“…The literature suggests that the anionic exchange prefers more divalent ions than monovalent ions for the same conditions [17]. This can be confirmed by the high retention capacity of As(V) species and the non-retention of As(III) species using the water-soluble polyelectrolyte at pH 9 with the LPR technique [19].…”

“…The ability of some polymers based on ammonium salts to remove arsenate species in solution by the LPR technique has been studied [17,18]. Different modes of separations by LPR can be used for inorganic ions.…”

“…Arsenic-specific extracting water-soluble polymeric reagents, with (R) 4 N + X − groups, and ultrafiltration membranes were combined in order to selectively separate arsenic species from other charged or neutral substrates in water [17,18]. Finally, the maximum retention capacity of arsenate by these polymers was determined.…”

Bacterial generation of liquid arsenic waste and the application of water-soluble polymers for arsenic ions separation

“…According to the literature, the anionic exchange process prefers divalent ions over monovalent ions under the same conditions (Rivas et al 2006). This effect can be confirmed using the high retention capacity of As(V) species and the nonretention of As(III) when using a water-soluble polymer at different pHs via the LPR technique.…”

“…At pH 6, the monovalent (H 2 AsO 4 -) and divalent (HAsO 4 2-) oxy-arsenic species exist in equilibrium, as corroborated by the higher retention capacity of predominantly divalent species at pH 9 by the polymers. The polymer interaction capacity depends on the presence of a positively charged quaternary ammonium group because the interactions are produced using ion exchange between the chloride counter-ion of the quaternary ammonium salt and the arsenate anions (Rivas et al 2006).…”