PropS-SH/SiO₂ nanocomposite coatings for pyrite oxidation inhibition to control acid mine drainage at the source

To control acid mine drainage (AMD) at the source, a novel nanocomposite coating, based on SiO₂ nanoparticles as nanofiller embedded in γ-mercaptopropyltrimethoxysilane (PropS-SH) coating is introduced in this paper. The performance of the PropS-SH/SiO₂ (PSS) nanocomposite coatings with a different content of SiO₂ nanoparticles on pyrite oxidation inhibition was evaluated by electrochemical measurements and chemical leaching testing. The results of the investigations revealed that the addition of appropriate SiO₂ nanoparticles could greatly enhance the passivation efficiency of PropS-SH coating. The best coating was obtained from 3% (v/v) of PropS-SH solution with 2wt% SiO₂ nanoparticles as this coating decreased pyrite oxidation by 81.1% (based on Fe release). In addition, the coating mechanism of PSS coatings on pyrite surfaces is presented in this paper.