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

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.

Removal of heavy metal ions using nano-cellulose prepared from rice husk: validation by differential pulse voltammetry

“…Also q cal are far away from qe exp . Nearly 60% removal e ciency was obtained at 30 o C and it was linearly decreased upto 50% when temperatures rise by 10 0 C. This is because of decrease in adsorption capacity with increase in temperature [27].…”

“…11c and d and Table 4, it is clari ed that, Freundlich's model can better predict metal ion adsorption by cellulosebecause correlation coe cient R 2 equal to unity (R 2 > 0.92) and the value of 1/n within limit 0.1 < 1/n < 1. Biological surfaces areexpected to have heterogeneous energies for adsorbing metals,and therefore a good t was expected [27].In Langmuir adsorption isotherm model, correlation coe cients R 2 are very small as compared to unity. Also q cal are far away from qe exp .…”