The reactive oxygen species produced by the oxidation of pyrite and its geochemical effects
Pyrite is the most widely distributed sulfide mineral in the earth's crust.Various reactive oxygen species(ROS)produced by the oxidation of pyrite played important roles in the transformation of environmental substances and the attenuation of pollutants.The present study systematically summarizes the reaction mechanisms and influencing factors on the ROS production through the pyrite oxidation,and geochemical effects of the ROS.Under the acidic and anoxic condition,the oxidation of adsorbed H2O by surface Fe3+at the sulfur defect is the main mechanism to produce·OH.Under the aerobic condition,the surface reaction of Fe(Ⅱ)with O2 produced H2O2,which can produce·OH through the heterogeneous/homogeneous Fenton reaction.Under the light irradiation,as a semiconductor mineral,pyrite produces photogenerated holes and electrons,which further promoted the ROS generation.The activity of the ROS generated by the oxidation of pyrite is affected by the selective faces of pyrite crystal,the isomorphous substitutions in the structure of pyrite and the coexisting substances in the environment.The ROS produced by the oxidation of pyrite could be one of the driving forces for the oxidation event of the early Earth,played important influence on the increase of global land-sea sulfur flux and the formation of banded iron formations,and played greatly controlling effects on the migration and transformation of pollutants of heavy metals and organic matters in the environment.The following aspects,including the contributions of homogeneous and heterogeneous reactions and various ROS products on the oxidation reaction,the influences of species of substituted metal ions and their microscopic coordination environment on the ROS production through the oxidation of pyrite,and the microstructural variation of the surface of pyrite during the reaction.
Pyriteoxidationreactive oxygen speciescrystal face effectisomorphic substitution
万方数据
维普
