Immobilization of Lead(II) Ions on Coal – A Thermodynamic View
Keywords:
adsorption thermodynamics, calorimetry, lead(II) ions, natural coalAbstract
Immobilization of Pb(II) ions from aqueous solutions on two types of coals and activated carbon was investigated at 30, 60 and 80 °C. Based on the thermodynamic analysis of the experimental data, changes in Gibbs energy, enthalpy and entropy of the adsorption were evaluated. The calculated values of the adsorption enthalpy were compared with Pb(II) adsorption heats determined experimentally using calorimetric measurements. Thus, noteworthy differences between the calculated and measured values were found for coal while for the activated carbon, the values were comparable. The discrepancy may be due to different mechanisms of the Pb(II) immobilization.