Manganese oxide-coated sand (MOCS) and manganese oxide-coated crushed brick (MOCB) were prepared and characterized and employed for the removal of phosphorus ions (PO4 3−) and Pb(II) and Ni(II) ions from aqueous solution. To study the surface properties of the adsorbents, scanning electron microscopy (SEM), X-ray diffraction (XRD) methods, and BET analyses were used. Adsorption was investigated by batch experiments. The estimated optimum pH was 7 for Ni(II) and 5 for all other ions retention by the two considered adsorbents. Both the Freundlich and Langmuir isotherms provided a reasonable fit to the experimental data for the adsorption. The adsorption capacities of the coated adsorbents at a considered pH value and a temperature of 20°C were 1.96 and 2.08 mg/g for PO4 3−, 2.4 and 3.33 mg/g for Ni(II), and 6 and 6.25 for Pb(II) onto MOCS and MOCB, respectively. The pseudo-first-order and pseudo-second-order equations as well as the intraparticle diffusion model were determined to test the adsorption kinetics and the rate constants derived from the three kinetic models being calculated. The pseudo-second-order kinetic model was better appropriated. Results obtained from this study confirm that the manganese oxide-coated sorbent is considerably considered like suitable for the removal of anions and cations from aqueous solutions.
Part of the book: Heavy Metal Toxicity in Public Health