The influence of humic acids on the weathering of pyrite: Electrochemical mechanism and environmental implications

摘要: Abstract Pyrite weathering often occurs in nature and causes heavy metal ion pollution acid mine drainage during the process. Humic (HA) is a critical natural organic material that can bind ions, thus affecting transfer transformation. In this work, situ electrochemical techniques combined with spectroscopic analysis were adopted to investigate interfacial processes involved pyrite with/without HA. The results showed mechanism HA FeS2 → Fe2+ + 2S0 + 2e−. presence of did not change mechanism, but adsorbs on surface inhibits further transformation sulfur. Furthermore, Fe(II) ions form complex at 45.0 °C. Increased concentration HA, decreased solution acidity or environmental temperature would all weaken weathering, for above conditions cause have larger resistance double layer passive film resistance. will release 73.7 g m−2·y−1 Fe2+ pH 4.5, amount decreases 36.8 g m−2·y−1 100 mg/L This study provides an method assessment weathering.