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Investigation on the adsorption characteristics of Pb(II) onto bone char

The adsorption characteristics of Pb(II) onto bone char were studied by conducting batch experiments, and the influence of the solid–liquid ratio, pH, ionic strength, reaction time, temperature, and initial concentration on Pb(II) adsorption was evaluated. Based on the adsorption kinetic and isothermal adsorption characteristics of Pb(II), Cd(II), Ni(II), and Cu(II), the competitive adsorption characteristics between heavy metal ions in the multi-component system were explored. The results reveal that bone char exhibits a relatively high adsorption capacity for Pb(II). The adsorption capacity reached 158.36 mg g–1 when the initial concentration was 200 mg L–1, the solid–liquid ratio was 1.0 g L–1, the temperature was 20°C, and the optimum pH was 2–3. Furthermore, Pb(II) adsorption onto bone char was substantially affected by the solid–liquid ratio and the pH, and less affected by the ionic strength. Langmuir model fit the isothermal processes better than the Freundlich model, and the coefficients of determination were larger than 0.970. Pseudo-second-order kinetic model was best fitted to the adsorption kinetic processes of Pb(II), Cd(II), Ni(II), and Cu(II), which had the coefficients of determination larger than 0.990. Moreover, Cd(II) and Ni(II) had a low impact on the adsorption capacity of bone char to Pb(II), while Cu(II) showed a significant impact.