针铁矿和水铁矿纳米粒子对间苯二酚二甲醚的氧化:铁还原与表面催化。
Oxidation of a Dimethoxyhydroquinone by Ferrihydrite and Goethite Nanoparticles: Iron Reduction versus Surface Catalysis.
机构信息
Centre of Environmental and Climate Research, Lund University , SE-223 62, Lund, Sweden.
Department of Biology, Lund University , SE-223 62, Lund, Sweden.
出版信息
Environ Sci Technol. 2017 Aug 15;51(16):9053-9061. doi: 10.1021/acs.est.7b02292. Epub 2017 Jul 26.
Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite promoted 2,6-DMHQ oxidation both via reductive dissolution and heterogeneous catalysis while goethite mainly caused catalytic oxidation. These results were in agreement with changes in the reduction potential (E) of the Fe(III) oxide/Fe(II) redox couple as a function of dissolved Fe(II) where E of goethite was lower than ferrihydrite at any given Fe(II) concentration, which makes ferrihydrite more prone to reductive dissolution by the 2,6-DMBQ/2,6-DMHQ redox couple. This study showed that reactions between hydroquinones and iron oxides could produce favorable conditions for formation of reactive oxygen species, which are required for nonenzymatic Fenton-based decomposition of soil organic matter.
对苯二酚是土壤中电子转移反应的重要介体,具有还原 Fe(III)矿物和分子氧的能力,从而生成芬顿化学试剂。本研究聚焦于 2,6-二甲氧基对苯二酚(2,6-DMHQ),这是一种常见真菌代谢物的类似物,及其在可变 pH 和氧气浓度下与水铁矿和针铁矿的反应。综合湿化学和光谱分析表明,两种矿物在氧气存在下均能有效氧化 2,6-DMHQ。在厌氧条件下,一级氧化速率常数取决于 pH 和矿物,降低了 1 到几个数量级。好氧和厌氧结果的比较表明,水铁矿通过还原溶解和非均相催化促进了 2,6-DMHQ 的氧化,而针铁矿主要引起催化氧化。这些结果与 Fe(III)氧化物/Fe(II)氧化还原对的还原电位(E)随溶解 Fe(II)的变化一致,在任何给定的 Fe(II)浓度下,针铁矿的 E 均低于水铁矿,这使得水铁矿更容易被 2,6-DMBQ/2,6-DMHQ 氧化还原对还原溶解。本研究表明,对苯二酚与氧化铁之间的反应可以产生形成活性氧的有利条件,这是基于非酶芬顿的土壤有机质分解所必需的。