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Polysaccharide-based adsorbents prepared in ionic liquid with high performance for removing Pb(II) from aqueous systems
- Rufato, Késsily B., Almeida, Vitor C., Kipper, Matt J., Rubira, Adley F., Martins, Alessandro F., Muniz, Edvani C.
- Carbohydrate polymers 2019 v.215 pp. 272-279
- X-ray photoelectron spectroscopy, adsorbents, adsorption, alginates, chitosan, infrared spectroscopy, ionic liquids, ions, lead, nuclear magnetic resonance spectroscopy, scanning electron microscopy, sulfates, zeta potential
- Alginate/chitosan (ALG/CHT) and alginate/N,N-dimethyl chitosan (ALG/DMC) polyelectrolyte complex (PEC)-based adsorbents with high capacities for removing Pb(II) from aqueous systems are produced in [1-hydrogen-3-methylimidazolium hydrogen sulfate ionic liquid ([Hmim][HSO4―]). The [Hmim][HSO4―] is recovered, characterized by 1H NMR and reused to yield novel polysaccharide-based adsorbents. As-obtained PEC materials are characterized through infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Zeta potential measurements. Kinetic and equilibrium adsorption studies reveal that the pseudo-second-order Kinetic, as well as the Redlich-Peterson isotherm, provide the best fits for the experimental data, respectively. CHT/ALG and DMC/ALG adsorbents promoted maximum adsorption capacities (qm) of 529.4 mg g−1 and 560.2 mg g−1, respectively. After adsorption, the materials are characterized by infrared spectroscopy and X-ray photoelectron spectroscopy, confirming that the chemisorption prevails upon Pb(II) removal. Also, PECs produced in the recovered [Hmim][HSO4―] have good capacities for removing Pb(II) ions from aqueous systems as well. This study showed that the [Hmim][HSO4―] is an alternative solvent to prepare novel and eco-friendly PEC-based adsorbents.