A new organosilane passivation agent prepared at ambient temperatures to inhibit pyrite oxidation for acid mine drainage control. (15th October 2022)

• Record Type: Journal Article
• Authors: Dong, Yingbo; Liu, Zhirui; Liu, Wei; Lin, Hai
• Is Part Of: Journal of environmental management. Volume 320(2022)
• Publication Date: 2022-10-15
• Subjects: Acid mine drainage abatement -- Organosilane coating -- Passivation -- Pyrite -- Ambient temperature; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.115835
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Acid mine drainage (AMD) is a significant environmental problem caused by the oxidation of pyrite and other metal sulfide ores. Organosilane passivation is an effective strategy to inhibit pyrite oxidation. However, synthetic organic silane passivation agents generally require temperatures of 50–80 °C, resulting in high energy consumption and high synthesis cost. In this study, a 3-aminopropyltrimethoxysilane -methyltrimethoxysilane (APS-MTMS) coatings was successfully prepared at ambient temperatures of 15–40 °C as a passivation agent to inhibit pyrite oxidation. Chemical leaching tests were used to study the inhibition performance of APS-MTMS for pyrite oxidation. The experimental results showed that the release of the total Fe from APS-MTMS-coated pyrite was 11.31 mg/L after chemical oxidation for 7 hours, and the passivation rate can reach 77.78%. The contact angle of the APS-MTMS-coated pyrite was significantly larger (140.4°) than that of the bare pyrite (58.8°), indicating that APS-MTMS prompted the formation of a superhydrophobic surface of pyrite, improving the oxidation resistance. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to probe the interaction mechanism of APS-MTMS with pyrite. The results indicated that APS accelerated the Si–O–Si formation by amino protonation and enriched a crosslinked network of Si–O–Si and Fe–O–Si on the pyrite surface to prevent pyrite oxidation. This study provides a novel method for preparing organosilane passivation materials at ambient temperatures for AMD control. Graphical abstract: Image 1 Highlights: Successfully prepared organosilane passivated materials at ambient temperatures. The passivation material exhibited 77.78% oxidation resistance of pyrite. Surface hydrophobicity of passivation agent coated pyrite was greatly improved. Good oxidation resistance is attributed to Si–O–Si and Fe–O–Si net structure.