锰
反应性(心理学)
歧化
背景(考古学)
焦磷酸盐
化学
氧化还原
无机化学
催化作用
地质学
有机化学
替代医学
酶
古生物学
病理
医学
生物化学
作者
Xingxing Wang,Qihuang Wang,Peng Yang,Xiaoming Wang,Liwu Zhang,Xionghan Feng,Mengqiang Zhu,Zimeng Wang
标识
DOI:10.1021/acs.est.0c05459
摘要
Dissolved Mn(III) species have been recognized as a significant form of Mn in redox transition environments, but a holistic understanding of their geochemical properties still lacks the characterization of their reactivity as reductants. Through using PbO2 as a surrogate oxidant and pyrophosphate (PP) as a model ligand, we evaluated the thermodynamic and kinetic constrains of dissolved Mn(III) oxidation under environmentally relevant pH. Without disproportionation, Mn(III) complexes could be directly oxidized by PbO2 to produce Mn oxides. The reaction rates decreased with increasing PP:Mn(III) ratio and became negligible when the ratio was above a threshold value. Particulate manganite could also be oxidized by PbO2 with detectable production of Pb(II). The favorability of Mn(III) oxidation by PbO2 as a function of the PP:Mn ratio could be predicted by the stability constant of the Mn(III)–PP complex. We developed kinetic models that couple multiple pathways of Mn oxidation by PbO2 to simulate the dynamics of Pb release, loss of dissolved Mn, as well as Mn(III) production and consumption. Beyond the context of Mn geochemistry, the interactions between Pb and various Mn species, including its trivalent forms, may also have important implications to the water quality in lead service lines within distribution systems.
科研通智能强力驱动
Strongly Powered by AbleSci AI