Investigation on modified Linz-Donawitz slag for the treatment of Pb2+ion-laden wastewater - A slag utilization sustainable approach

The present study investigated the adsorptive chemistry of Pb 2 + ions eradication using modified Linz-Donawitz slag (LDS), a byproduct of steelmaking industries. The processing of LDS was carried out using a magnetic separation technique followed by planetary micro-crushing. The morphology of surface texture and elemental composition of LDS were examined using SEM and EDS techniques, respectively. XRD and FTIR analysis revealed that the divalent cation of Pb 2 + was replaced by Ca 2 + to form metal silicate (Pb 2 SiO 4 ) and ferrite (Pb 2 Fe 2 O 5 ) through ion exchange and finally precipitated. The experiment data best fitted Langmuir isotherm and showed excellent adsorption capacity of LDS for Pb 2 + adsorption (479 mg/g). Thermodynamic parameters, Gibbs free energy ( Delta G o ), and enthalpy change ( Delta H o ) indicated the adsorption was spontaneous and endothermic. The leachability study done by the ICP-OES technique suggested the possibility of immobilizing Ca and Si due to the dissolution of CaO and SiO 2 . The study demonstrated the potential of LDS for treating Pb 2 + ions as part of the waste utilization of the steel industry for a sustainable approach.