Novel active heterogeneous Fenton system based on Fe3-xMxO4 (Fe, Co, Mn, Ni):: The role of M2+ species on the reactivity towards H2O2 reactions
Novel active heterogeneous Fenton system based on Fe3-xMxO4 (Fe, Co, Mn, Ni):: The role of M2+ species on the reactivity towards H2O2 reactions
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DOI：
10.1016/j.jhazmat.2005.08.028
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发表时间：
2006-02-28
影响因子：
13.6
通讯作者：
Lago, RM
中科院分区：
文献类型：
--
作者：
Costa, RCC;Lelis, MFF;Lago, RM
在这项工作中，将M2+物种，即Co2+，Mn 2+和Ni 2+，到磁铁矿结构，以增加对H2 O2反应的反应性的效果进行了研究。制备了Fe_（3-x）Mn_xO_4、Fe_（3-x）Co_xO_4、Fe_（3-x）O_4和铁氧化物Fe_3 O_4、γ-Fe_2 O_3、α-Fe_2 O_3，并通过穆斯堡尔谱、XRD、BET比表面积、磁化强度和化学分析进行了表征。结果表明，磁铁矿中八面体位置的M2+物种强烈影响H2 O2的反应活性，即（i）过氧化物分解为O-2和（ii）有机分子的氧化，如染料亚甲基蓝和氯苯在水介质中。磁赤铁矿，γ-Fe_2O_3和赤铁矿，α-Fe_2O_3的实验表明，与Fe_3O_4相比，活性非常低，这表明氧化物中Fe ~（2+）的存在对H_2O_2的活化起着重要作用。在磁铁矿结构中的Co或Mn的存在下产生的反应性显着增加，而Ni抑制H2 O2反应。所获得的结果表明，涉及M-surf（2+）（Fe，Co或Mn）的表面引发的反应，产生HO。自由基，其可导致两个竞争性反应，即H2 O2的分解或存在于水性介质中的有机物的氧化。从Fe-磁铁矿（2+）对Co-surf（3+）和M-surf（3+）的还原作用以及对活性物种M2+的再生作用方面讨论了Co和Mn的独特作用。(c)2005 Elsevier B. V.保留所有权利。
In this work, the effect of incorporation of M2+ species, i.e. Co2+, Mn2+ and Ni2+, into the magnetite structure to increase the reactivity towards H2O2 reactions was investigated. The following magnetites Fe3-xMnxO4, Fe3-xCoxO4 and Fe3-xO4 and the iron oxides Fe3O4, gamma-Fe2O3 and alpha-Fe2O3 were prepared and characterized by Mossbauer spectroscopy, XRD, BET surface area, magnetization and chemical analyses. The obtained results showed that the M2+ species at the octahedral site in the magnetite strongly affects the reactivity towards H2O2, i.e. (i) the peroxide decomposition to O-2 and (ii) the oxidation of organic molecules, such as the dye methylene blue and chlorobenzene in aqueous medium. Experiments with maghemite, gamma-Fe2O3 and hematite, alpha-Fe2O3, showed very low activities compared to Fe3O4, Suggesting that the presence of Fe2+ in the oxide plays an important role for the activation of H2O2. The presence of Co or Mn in the magnetite structure produced a remarkable increase in the reactivity, whereas Ni inhibited the H2O2 reactions. The obtained results suggest a surface initiated reaction involving M-surf(2+) (Fe, Co or Mn), producing HO. radicals, which can lead to two competitive reactions, i.e. the decomposition of H2O2 or the oxidation of organics present in the aqueous medium. The unique effect of Co and Mn is discussed in terms of the thermodynamically favorable Co-surf(3+) and M-surf(3+) reduction by Fe-magnetite(2+) regenerating the active species M2+. (c) 2005 Elsevier B.V. All rights reserved.