Chitosan cross-linked and grafted with epichlorohydrin and 2,4-dichloro-benzaldehyde as an efficient adsorbent for removal of Pb(II) ions from aqueous solution

Epichlorohydrin-modified chitosan-Schiff base composite (CS/24Cl/ECH) prepared via the one-pot reaction as characterized by Fourier transform Infra-Red spectroscopy (FT-IR), X-ray powder diffraction (XRD), Differential scanning calorimetry (DSC) and Scanning electron microscope (SEM). Its removal ability of Pb(II) ions from aqueous solution was investigated. The adsorption of Pb(II) ions carried out at different initial pH, dose of CS/24Cl/ECH, contact time and co-existing ions. The maximum adsorption capacity of Pb(II) ions was 170 mg/g. Finally, based on the absorption results, the adsorption of Pb(II) ions was fitted by single-layer Langmuir isotherm model and the pseudo-second-order (PSO) kinetics model. The absorption mechanism of Pb(II) ions was controlled by chemical coordination Pb(II) ions with the active sites on the surface of CS/24Cl/ECH composite. Also, CS/24Cl/ECH showed excellent recyclable efficiency up to 5 cycle and potential sorbent for other heavy metal ions.

Automated summary

Epichlorohydrin-modified chitosan-Schiff base composite (CS/24Cl/ECH) was characterized using FT-IR, XRD, DSC, and SEM. The removal efficiency of Pb(II) ions from aqueous solution was investigated. The maximum adsorption capacity of Pb(II) ions was found to be 170 mg/g. The adsorption mechanism involved chemical coordination between Pb(II) ions and the active sites on the surface of CS/24Cl/ECH composite. CS/24Cl/ECH also showed excellent recyclability and potential for adsorption of other heavy metal ions.