The thermodynamics of sequestration of toxic copper(ii) metal ion pollutants from aqueous media by l-cysteine methyl ester modified glassy carbon spheres

Abstract

l-Cysteine methyl ester modified glassy carbon powder (CysOMe-GC) has been shown to have potential for the removal of toxic heavy metal ions, such as copper(ii), cadmium(ii) and arsenic(iii), from "real" water samples. To develop this material for environmental applications we must develop an understanding of the thermodynamic parameters controlling the uptake of metal ions by the modified carbon powder. Here we characterise the material using X-ray photoelectron spectroscopy (XPS), before investigating the effect of varying the solution pH, the concentration of copper(ii) ions and the mass of CysOMe-GC powder added to the solution using square wave voltammetry (SWV). This data allows us to understand the thermodynamics controlling the copper(ii) ion uptake and elucidate that the adsorption of copper(ii) onto the CysOMe modified surface is controlled by a Freundlich isotherm.