C. V. Abiaziem, C. T. Onwordi, L. F. Petrik and A. B. Williams

DOI: 10.14456/sjst-psu.2021.176

pp. 1351 - 1359

Abstract

Cd²⁺ adsorption from aqueous solution onto cellulose nanocrystals from cassava peel (CP) was successfully studied.
The sample was acid hydrolysed into cellulose nanocrystals using 64% sulphuric acid at 45^oC for 45 min and was used as an
adsorbent for the removal of Cd²⁺ from aqueous solution. Cellulose nanocrystals were characterised using high-resolution
scanning electron microscope (HR-SEM), x-ray diffraction (XRD), and thermogravimetric analysis (TGA). The different
optimization factors were studied. The adsorption equilibrium data were best fit by the Freundlich model with an R² of 1,
indicating good surface heterogeneity of the active sites. Kinetic data were best fit by the pseudo-second order model type. The
thermodynamic parameters enthalpy, entropy, and the negative change in Gibbs free energy, imply that the adsorption of Cd2⁺
onto CPCNC was exothermic, spontaneous, and feasible. This nanomaterial has good potential for use in successful removal of
Cd²⁺ from wastewaters.

Keywords

• adsorption
• Cd²⁺
• cellulose nanocrystals
• cassava peel
• isotherm studies