Dissolution and sorption mechanisms at the aluminosilicate and carbonate mineral-AMD (Acid Mine Drainage) interface

• Published in: Applied geochemistry Vol. 131; p. 105027
• Main Authors: Kollias, Konstantinos, Godelitsas, Athanasios, Astilleros, Jose Manuel, Ladas, Spyridon, Lagoyannis, Anastasios, Mavromoustakos, Thomas
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2021
• Subjects: 29Si and 27Al NMR spectroscopy; Acid mine drainage; Atomic force microscopy; Calcite; Dissolution and sorption mechanisms; HEU zeolite; Mineral surfaces; Surface analysis; Mineral surfaces; Atomic force microscopy; HEU zeolite; 29Si and 27Al NMR spectroscopy; Dissolution and sorption mechanisms; Acid mine drainage; Surface analysis; Calcite
• ISSN: 0883-2927; 1872-9134
• DOI: 10.1016/j.apgeochem.2021.105027

Aluminosilicate/silicate and carbonate materials (pure and industrial) interacted with natural Acid Mine Drainage (AMD) under ambient conditions for different time periods in order to elucidate the chemical processes at the aluminosilicate and carbonate mineral-AMD interface. More precisely, powdered materials were subjected to macroscopic neutralization experiments (using on-line pH-measurements, Inductively Coupled Plasma Optical Emission Spectroscopy, Powder X-ray Diffraction and Scanning Electron Microscopy with Energy Dispersive Spectroscopy), whereas interacted mm-sized single crystals were examined by means of nanoscale microscopic (in-situ Atomic Force Microscopy) and surface & bulk spectroscopic techniques (X-ray Photoelectron Spectroscopy, 12C-Rutherford Backscattering Spectroscopy, Solid-State 29Si and 27Al Magic-Angle-Spinning Nuclear Magnetic Resonance). The carbonates were proven to be more effective for neutralization of AMD, related to adequate removal of metals from the contaminated aqueous medium, but they are readily dissolved. The application of aluminosilicate/silicates showed that the removal of metals is considerably lower, and the pH stabilized at lower values, but they are more resistant. The investigation of interacted zeolite and calcite crystals revealed changes to the macrotopography, microtopography and nanotopography of surfaces. It was indicated that coupled dissolution and sorption (surface precipitation/co-precipitation, nucleation/crystal growth, adsorption or even absorption-including solid-state diffusion) phenomena occur simultaneously. Based on the experimental results, two generalized models -in nano(molecular)-scale- can be suggested regarding interaction of AMD with aluminosilicate and carbonate mineral surfaces.
•Aluminosilicate/silicate and carbonate minerals and rocks interacted with AMD.•Surface nanotopography is investigated by in situ AFM.•Fe-oxyhydroxides/Fe-sulphates coating on treated surfaces is identified by XPS/RBS.•Coupled dissolution/sorption occurred in micro/nano(molecular)-scale.