Adsorption studies of Cu (II), Pb (II) and Cr (VI) by chitosan/unitiol composite

Abstract

Chitosan-unithiol composite for the first time was synthesized by simple and short period procedure. The sorption process was carried out under static conditions at temperature 298 K and at pH=4.5. The concentration of ions of toxic metals before and after sorption was determined by the atomic absorption method. The removal characteristics such as the removal degree and equilibrium time of Cu²⁺, Pb²⁺ and Cr⁶⁺ were illustrated. The adsorption equilibrium for Cu²⁺ ions was best described by Langmuir model and for Pb²⁺ and Cr⁶⁺ ions by Freundlich model. It was found that adsorption of Cu²⁺ and Cr⁶⁺ by chitosan-unithiol followed first-order kinetics. Adsorption of Pb²⁺ was followed second-order kinetics. The sorption process was also investigated under co-presence of heavy metal ions. The obtained results indicate that the synthesized chitosan-unithiol composite is the effective sorbent for removing toxic metal ions.