Thermodynamic properties of divalent cations complexed by ethylenesulfide immobilized on silica gel

Thermodynamic data of the energetic interaction of some cations like Cd, Pb, Hg, Cu, Ni, and Co with silica modified by 3-mercaptopropyltrimethoxysilane have been obtained through calorimetric titration. The amount of ethylenesulfide anchored on silica surface was estimated to be 0.80 mmol g−1. The ΔH values of metal ion binding with the modified silica were found to be −11.10 ± 0.5, −10.18 ± 0.3, −5.65 ± 0.2, −7.33 ± 0.2, −1.52 ± 0.1, and −4.11 ± 0.2 kJ mol−1 for divalent cations Co, Cu, Ni, Cd, Pb and Hg, respectively.