Removal of Pb (II) ions using chitosan oligosaccharide/carboxymethyl starch blend crosslinked with glutaraldehyde: a study on batch adsorption

Heavy metal removal from wastewater has emerged as a major environmental concern on a global scale. The primary objective of this study was to determine how well lead (Pb) can be removed from wastewater by adsorptive processes using a chitosan-oligosaccharide-based hybrid (chitosan oligosaccharide (COS)/carboxymethyl starch binary blend material developed in the presence of glutaraldehyde (Glu). The amine and hydroxyl groups in the COS structure, the hydroxy and carboxy groups in the carboxymethyl starch, and the imine groups created when the amino group of COS reacts with the aldehydic group glutaraldehyde aid in the removal of Pb ions. FTIR, SEM, and X-ray diffraction were used to characterize the COS/CMC + Glu blend. Batch adsorption experiments, in which various factors including the impact of initial concentration, the dose of adsorbent, and the duration of contact, were used to analyze the removal of ions. The pH-dependent adsorption of Pb ions peaked at pH 5. The favorability of the reported experimental data was confirmed using various theoretical models, such as the Freundlich, the Langmuir isotherms, and pseudo-first- and pseudo-second-order kinetics. Adsorption was best fit by the pseudo-second-order and Langmuir isotherms.

Graphical abstract