Effects of Fe oxides and their redox cycling on Cd activity in paddy soils: A review

Gao, Yining; Tong, Hui; Zhao, Zhikai; Cheng, Ning; Wu, Pan

doi:10.1016/j.jhazmat.2023.131665

Cited by 29 publications

(2 citation statements)

References 135 publications

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“…14 In natural environments, the adsorbed Fe has a tendency to transform into more stable structural Fe. 33 The sequential extraction results of iron plaque (Figure 3b) showed that the adsorbed and structural Fe accounted for 23.9% and 76.1% of the total iron plaque, respectively. In the structural Fe, weak crystal minerals (ferrihydrite and/or lepidocrocite) and crystalline iron minerals accounted for 62.6% and 37.4%, respectively.…”

Section: ■ Resultsmentioning

confidence: 96%

“…The species of Fe in the iron plaque could be divided into surface-adsorbed Fe and mineral structural Fe (Figure a) . In natural environments, the adsorbed Fe has a tendency to transform into more stable structural Fe . The sequential extraction results of iron plaque (Figure b) showed that the adsorbed and structural Fe accounted for 23.9% and 76.1% of the total iron plaque, respectively.…”

Section: Resultsmentioning

confidence: 99%

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New Barrier Role of Iron Plaque: Producing Interfacial Hydroxyl Radicals to Degrade Rhizosphere Pollutants

Meng,

Zhang,

et al. 2023

Environ. Sci. Technol.

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Iron plaque, as a natural barrier between rice and soil, can reduce the accumulation of pollutants in rice by adsorption, contributing to the safe production of rice in contaminated soil. In this study, we unveiled a new role of iron plaque, i.e., producing hydroxyl radicals (•OH) by activating rootsecreted oxygen to degrade pollutants. The •OH was produced on the iron plaque surface and then diffused to the interfacial layer between the surface and the rhizosphere environment. The iron plaque activated oxygen via a successive three-electron transfer to produce •OH, involving superoxide and hydrogen peroxide as the intermediates. The structural Fe(II) in iron plaque played a dominant role in activating oxygen rather than the adsorbed Fe(II), since the structural Fe(II) was thermodynamically more favorable for oxygen activation. The oxygen vacancies accompanied by the structural Fe(II) played an important role in oxygen activation to produce •OH. The interfacial •OH selectively degraded rhizosphere pollutants that could be adsorbed onto the iron plaque and was less affected by the rhizosphere environments than the free •OH. This study uncovered the oxidative role of iron plaque mediated by its produced •OH, reshaping our understanding of the role of iron plaque as a barrier for rice.

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Section: ■ Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%