Cellulose Derivatives Functionalized with Multidentate N‑Donor Atoms: Comparative Adsorption of Cadmium(II) and Lead(II) Ions from Water

Abstract

Abstract Cellulose derivatives functionalized with multidentate N‑donor atoms containing two, three and four amino functional groups (as marked N2-CL, N3-CL and N4-CL) have been prepared by grafting of linear aliphatic polyamines into the cellulose backbone through the Schiff base reaction. Adsorption performances of these cellulose derivatives have been compared. An increase in the adsorptive amounts of Cd2+ and Pb2+ ions with increasing N‑donor atoms of the grafted polyamines onto the cellulose backbone is found to give the maximum capacity N4-CL > N3-CL > N2-CL for both the ions. The N4-CL with high N content (up to 5.2 mmol N g− 1) exhibits higher adsorptive capacities of 249.7 mg g− 1 for Cd2+ and 401.2 mg g− 1 for Pb2+. The adsorption of both the ions by the three cellulose derivatives is achieved within 30 min, is independent of pH in the range of 4.5-6 for Cd2+ and 4–6 for Pb2+, and can be satisfactorily fitted by Langmuir and pseudo-second-order equations. Thermodynamic parameters for the adsorption of both the ions suggest an endothermic and endothermic nature and favorable interactions between N‑donor atoms and the ions. The developed cellulose derivatives are promising for the enhanced removal of Cd2+ and Pb2+ from water.