Sorption of trace heavy metals by thiol containing chelating resins

The sorption of copper, cadmium, nickel and zinc ions on thiol (-SH) based chelating polymeric resins (thiomethyl resin and Duolite GT-73) has been in vestigated. The physical and chemical characterisation of these polymers in the form of scanning electron micrographs (SEM), BET and Langmuir surface area measurements, Fourier transform infra red spectroscopy (FTIR) analysis , X-ray photoelectron spectroscopy (XPS) analysis, atomic composition measu rement, sodium capacity determination and zeta potential measurements have been conducted to assess their performance as sorbents for trace toxic meta l removal. Density functional theory (DFT) has been used to analyse the por e size distribution data. The adsorption of metal ions from aqueous solutio n on these sorbents has been studied in batch equilibrium experiments. The influence of pH on metal adsorption capacity has also been examined. The ki netic performance of these polymers has been assessed and the results have been analysed by a pore diffusion model. The resins have been used in mini- columns to study the selectivity towards the desired metal ion. The desorpt ion of metal ions has been studied using hydrochloric acid (1 M and 4 M), s ulphuric acid (1 M and 4 M) and acidified thiourea. The present study confi rms that these thiol based chelating resins are very effective for selectiv e removal of trace heavy metals from Water.