Effective treatment of real acid mine drainage using MgO-metakaolinite nanocomposite

In this study, synergistic effects of mechanochemically synthesized metakaolinite-Ca-rich-MgO nanocomposite for effective treatment of real acid mine drainage (AMD) was meticulously reported. The obtained results were underpinned using the state-of-the-art analytical techniques and instruments, such as FTIR, HR-FIB/SEM, EDS, XRF, and XRD. The pH REdox EQuilibrium (in C language) was employed to complement experimental results. Optimum conditions were observed to be 45–60 min of mixing time, ≥10 g L−1 of feedstock dosage, i.e. nanocomposite, and ambient temperature and pH. The metal content (Fe, Mn, Cr, Cu, Ni, Pb, Al, and Zn) embedded in real AMD matrices was practically depleted (>99 % removal) and sulphate greatly reduced (≥50 %). PHREEQC predicted metals to exist as mono-, di-, and-tri-valents including variety of chemical complexes, and they precipitated as metals hydroxides, (oxy)-hydroxides, carbonates, and (oxy)-hydro-sulphates. This synergistic treatment approach holds great promise for the sustainable management of real AMD effluents from coal mining activities and can provide a simple and effective solution for its management. Thenceforth, softening and filtration technologies will need to be coupled to this process to further enhance the reclamation of drinking and to explore possible recovery of valuable minerals from the generated sludge.