As(III) oxidation kinetics of biogenic manganese oxides formed by Acremonium strictum strain KR21-2
As(III) oxidation kinetics of biogenic manganese oxides formed by Acremonium strictum strain KR21-2
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DOI：
10.1016/j.chemgeo.2013.03.012
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发表时间：
2013-06
期刊：
影响因子：
3.9
通讯作者：
J. Watanabe;Y. Tani;Jianing Chang;N. Miyata;H. Naitou;H. Seyama
中科院分区：
文献类型：
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作者：
J. Watanabe;Y. Tani;Jianing Chang;N. Miyata;H. Naitou;H. Seyama
我们研究了As（III）的氧化动力学的生物锰氧化物（BMOs）收获在不同阶段的形成由锰氧化真菌，枝顶孢菌株KR 21 -2。在BMO形成的早期阶段收获的未成熟BMO富含低价Mn（II）和Mn（III），氧化As（III）非常缓慢。随着BMO的成熟，BMO中的Mn（IV）含量增加，并具有较高的As（III）氧化速率。较慢的As（III）的氧化速率的不成熟的BMO可能是由于网站阻塞由大量的吸附Mn（II）和/或由于增加的结构Mn（III），这是反应性低于Mn（IV）。新鲜成熟的BMO表现出不同的As（III）氧化动力学取决于溶解氧。在脱气的解决方案中，As（III）的氧化速率较慢，Mn（II）被释放作为As（III）的氧化进展，表明表面钝化与还原的氧化锰相产生Mn（II）和可能的Mn（III）。与此相反，在空气平衡的解决方案，作为（III）氧化遵循伪一级速率动力学在整个反应过程中没有明显的钝化或显着释放锰（II）。我们假设，活性锰（II）氧化酶存在于BMO再氧化锰（II）和锰（III）作为高压灭菌的BMO表现出表面钝化，即使在空气平衡条件下。BMO的这种自我再生使钝化最小化，因此是连续As（III）氧化的重要途径。提出的数据提供了新的见解BMO作为补救以及氧化处理的化学品以外的作为（III）的潜在适用性。
We investigated As(III) oxidation kinetics of biogenic manganese oxides (BMOs) harvested at various stages of formation by a manganese-oxidizing fungus, Acremonium strictum strain KR21-2. Immature BMOs harvested at an early stage of BMO formation were rich in lower-valence Mn(II) and Mn(III) and oxidized As(III) very slowly. As the BMOs matured, the Mn(IV) content in the BMOs increased and had higher As(III) oxidation rates. The slower As(III) oxidation rates of the immature BMOs may be due to site-blocking by larger amounts of sorbed Mn(II) and/or due to increased structural Mn(III), which is less reactive than Mn(IV). Freshly mature BMOs demonstrated varying As(III) oxidation kinetics depending on dissolved oxygen. In deaerated solutions, the As(III) oxidation rate was slower and Mn(II) was released as As(III) oxidation progressed, indicating surface passivation with reduction of the manganese oxide phase producing Mn(II) and possibly Mn(III). In contrast, in air-equilibrated solutions, As(III) oxidation followed pseudo-first-order rate kinetics throughout the reaction without apparent passivation or significant release of Mn(II). We hypothesize that the active Mn(II) oxidase present in BMOs reoxidized Mn(II) and Mn(III) as autoclaved BMOs exhibited surface passivation even under air-equilibrated conditions. This self-regeneration of BMO minimizes passivation and is hence an important pathway for continuous As(III) oxidation. The data presented provide new insights into the potential applicability of BMOs for As remediation as well as for the oxidative treatments of chemicals other than As(III).