Polysaccharide-based adsorbents prepared in ionic liquid with high performance for removing Pb(II) from aqueous systems.

• Chitosan/alginate and N,N- dimethyl chitosan/alginate-based adsorbents are prepared. • An ionic liquid is used to carry out the polysaccharide-based adsorbents. • Adsorbents are produced by precipitating of blends performed in an ionic liquid. • The ionic liquid is recovered and reused to create new adsorbents. • The adsorbents have high capacity for removing Pb(II) ions from aqueous systems. 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][HSO 4 ―]). The [Hmim][HSO 4 ―] 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 (q m) 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][HSO 4 ―] have good capacities for removing Pb(II) ions from aqueous systems as well. This study showed that the [Hmim][HSO 4 ―] is an alternative solvent to prepare novel and eco-friendly PEC-based adsorbents. [ABSTRACT FROM AUTHOR]