Uptake of heavy metal ions from aqueous solutions by sorbents obtained from the spent ion exchange resins

Obtaining useful sorbents from spent materials is of great importance. The paper presents the results of tests determining the kinetic and adsorption parameters on the removal of heavy metal Cu(II), Cd(II), Co(II) and Pb(II) ions on the carbonaceous adsorbents W1 KPS, W2 KPS, D1 CC3 and D2 CC3 obtained from spent ion exchangers. Among others the sorption effects of contact time, initial concentration, solution pH, influence of interfering ions were studied. W1 KPS obtained by the microwave heating exhibits a higher affinity for heavy metal ions than W2 KPS. However, for the sorbent obtained in the resistance furnace higher values of the sorption capacity were obtained for D2 CC3 rather than D1 CC3. It was found that the sorption capacity increases with the increasing initial concentration of the solution and phase contact time. The maximum pH adsorption was found at pH 5.0. A better fit of the kinetic data from the experimental one was presented using the pseudo second order model. In this paper, desorption using acidic desorbing agents was also examined. The results show that 2 M HNO3 is the most effective desorbing agent. Carbonaceous sorbents were characterized using elemental analysis, Fourier transform infrared spectroscopy and point of zero charge measurements. Differential scanning calorimetry analysis was also conducted.