Novel N-methyl-D-glucamine-based water-soluble polymer and its potential application in the removal of arsenic

Abstract

A new water-soluble polymer based on the N-methyl-D-glucamine (NMG) group was prepared and characterized, and its arsenic retention capacity was studied using the liquid-phase polymer-based retention (LPR) technique.The monomer glycidyl methacrylate-N-methyl-D-glucamine (GMA–NMG) was synthesized, and the polymer was subsequently obtained through radical polymerization using ammonium persulfate as an initiator reagent. The polymer was dissolved in water, purified and fractionated with ultrafiltration membranes with molecular weight cut-offs of 50,000Da. The polymer was then characterized by potentiometric titration, FTIR and 1H NMR spectroscopy.The removal of arsenic was analyzed using the LPR technique with both the washing and enrichment methods. The removal experiments using the washing method were conducted by varying the pH, polymer:As(V) molar ratio, and concentrations of interfering ions. P(GMA–NMG) showed a high affinity for binding arsenate species (82% of removal) at pH 3.0. The optimum molar ratio was 70:1 polymer:As(V). Selectivity experiments showed that the presence of interferents gradually decreased the arsenic removal capacity. The maximum retention capacity was determined by the method of enrichment, obtaining a value of 45.9mgAsg−1 polymer.Finally, the results showed that the combination of P(GMA–NMG) with ultrafiltration membranes is a potential alternative for the removal of hazardous As(V) species from aqueous solutions at acidic pH.