Abstract
Manganese oxide-coated sand (MOCS) and manganese oxide-coated crushed brick (MOCB) were characterized and employed for the removal of Pb(II) ions from aqueous solution. Scanning electron microscopy (SEM), FT-IR, X-ray diffraction (XRD) methods and BET analyses were used to study the surface properties of the adsorbents. Adsorption of Pb(II) ions from aqueous solutions was investigated by batch experiments. The estimated optimum pH for Pb(II) ion retention by the considered adsorbents was 5.
Both the Freundlich and Langmuir isotherms provided a reasonable fit to the experimental data for the adsorption of Pb(II) ions. The adsorption capacities of the coated adsorbents at a pH value of 5 and a temperature of 20 °C were 0.029 mmol/g and 0.030 mmol/g for MOCS and MOCB, respectively. The adsorption kinetics were tested using the pseudo-first-order and pseudo-second-order equations as well as the intraparticle diffusion model, with the rate constants from the three kinetic models being calculated. The best correlation coefficients were obtained using the pseudo-second-order kinetic model. Results from this study suggest that the manganese oxide-coated sorbent is potentially suitable for the removal of Pb(II) ions from aqueous solutions.