Steel-Making dust as a potential adsorbent for the removal of lead (II) from an aqueous solution

The presence of high concentrations of toxic heavy metals such as lead Pb(II) in water is a major hazard to human health and may have a detrimental effect on the aquatic life and the environment. Implementing an efficient and economical treatment method for the reduction of Pb(II) is a major challenge that is being addressed through employing such processes as adsorption, utilizing low cost adsorbents. In this study, SteelMaking dust obtained from a local Steel Factory was utilized for the adsorption of lead Pb(II) from an aqueous solution. The determination of optimum pH condition, adsorption isotherms and kinetics studies were carried out. The experimental data were fitted to five different isotherms, including Langmuir, Freundlich, Sips, Dubinin-Radushkevich and exponential models; while the kinetic data were fitted to Pseudo-first order, Pseudosecond order, Elovich's and intraparticle diffusion models. The fitting of the isotherm experimental data to the five isotherm models was compared through the Akaike Information Criterion (AIC). The Dubinin-Radushkevich model was found to best describe the experimental data for the adsorption of lead ions onto Ladle furnace and cyclone steel dust with high Akaike weight (w(i)) of 0.91 and 0.83, respectively. The optimum pH range was found to be around 4-5; working within this range prevents lead precipitation during the adsorption process. The maximum adsorption capacity for lead on Steel Dust as obtained from the Langmuir isotherm was 208.9 mg/g for the Ladle Furnace steel dust, and 39.8 mg/g for the Cyclone steel dust. Overall, the Steel-Making dust gave a high efficiency for the reduction of lead concentration in the aqueous solutions and thus could be utilized in industrial adsorption processes.