Adsorption properties of crosslinked carboxymethyl-chitosan resin with Pb(II) as template ions

In the current study, we attempt to find a new adsorbent material based on chitosan to improve adsorption selectivity for heavy metals, so that the crosslinked N,O-carboxymethyl-chitosan resin with Pb(II) as template ions (crosslinked CMC template) were synthesized by using CMC adsorbed Pb(II) ions crosslinked with glutaraldehyde. The effects on adsorption capacities such as amount of crosslinking agent, degree of substitution of CMC, pH value of the initial solution and adsorption time were investigated. The adsorption experiments demonstrated the crosslinked CMC template has high adsorption selectivity for Pb(II) ions in solution containing single metal ions or coexistence of three metals ions of Cu(II), Zn(II) and Pb(II). Furthermore, it was investigated that the crosslinked CMC template has a good reusability and stability as compared to CMC. Finally, we studied the adsorption mechanism by FTIR spectra and XPS analysis. The results reveal that the adsorption of crosslinked CMC template and CMC for Pb(II) is a chelation process.