Pyrophyllite as a Sustainable Material for Purification of Mine-Waste Water

Wastewater from mines poses a significant problem as it often contains high concentrations of metals, which are discharged into river systems, thereby contributing to environmental pollution. Pyrophyllite is a natural hydrous aluminum silicate clay mineral (Al2Si4(OH) 10(OH) 2) with a high melting point, stable chemical properties, and low cost. The elementary sheet of pyrophyllite is composed of an aluminum-oxygen/hydroxyl octahedral layer between two tetrahedral layers of silicon-oxygen. The layered silicate structure of pyrophyllite crystals has natural adsorption activity. Mechanochemical activation (MCA) is a simple method for modification of solid materials that causes structural disorder, amorphization and increased chemical reactivity. MCA, usually performed by grinding, is an environmentally friendly process because of low energy consumption, processing temperatures and cost. This study investigates the adsorption kinetics of the divalent metal ions (Cd, Ni, Cu, Zn, and Pb) from aqueous solutions using pyrophyllite as an adsorbent. It was found that the removal depends on the mechanochemical treatment of pyrophyllite, contact time with the aqueous solution, and the mutual competition of ions. The conditions were optimized for maximum removal of metal ions from synthesized aqueous solutions. Subsequently, pyrophyllite was applied under optimal conditions for removing Zn (II) from the wastewater of the closed Red Hill mine on mountain Avala. Based on the obtained results, it can be concluded that pyrophyllite completely removes zinc from mine water in a very short time (10 minutes) and thus has great potential for application