Influence of pH on cadmium, copper, and lead removal from wastewater by steel slag

Steel slag is a byproduct of steel manufacturing which raises an important environmental concern due to the high volume of generation and, specially, its basicity. The aim of this work was to determine its recycling potential and use for the removal of Cd, Cu, and Pb given its ability to increase the pH of a solution to values close to 13.5. Remediation of cadmium-, copper-, and lead-contaminated water was studied by means of induced precipitation/sorption reactions. Precipitation of these metals was evaluated by kinetic and batch tests that were analyzed by commonly used sorption models. The results confirmed that Cd, Cu, and Pb can be removed from solutions by the addition of steel slag particles, while the removal efficiency depends on metal type and on the ion interaction, concentration, and pH of precipitation of each metal.