Reduction and adsorption mechanisms of selenate by zero-valent iron and related iron corrosion

Yoon, In-Ho; Kim, Kyoung-Woong; Bang, Sunbaek; Kim, Min

doi:10.1016/j.apcatb.2011.02.014

Cited by 139 publications

(95 citation statements)

References 40 publications

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“…In all of the experiments, the Se(VI) concentration continuously decreased as a function of time. Se(VI) was completely removed by ZVI from the solutions containing 10 and 25 mg/L Se(VI) within 10 h. Approximately 30 (60 %) and 48 (48 %) mg/L Se(VI) was removed from the 50 and 100 mg/L Se(VI) solutions within 10 h, respectively (Yoon et al 2011). According to the results, the initial Se(VI) concentration was determined as 50 mg/L to evaluate the effect of Fe(II).…”

Section: Effect Of Fe(ii) On the Removal Of Se(vi) By Zvimentioning

confidence: 99%

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Selenate removal by zero-valent iron in oxic condition: the role of Fe(II) and selenate removal mechanism

Yoon

Bang²,

Kim

et al. 2015

Environ Sci Pollut Res

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In this study, batch experiments were conducted to investigate the effect of the concentration of ferrous [Fe(II)] ions on selenate [Se(VI)] removal using zero-valent iron (ZVI). The mechanism of removal was investigated using spectroscopic and image analyses of the ZVI-Fe(II)-Se(VI) system. The test to remove 50 mg/L of Se(VI) by 1 g/L of ZVI resulted in about 60% removal of Se(VI) in the case with absence of Fe(II), but other tests with the addition of 50 and 100 mg/L of the Fe(II) had increased the removal efficiencies about 93 and 100% of the Se(VI), respectively. In other batch tests with the absence of ZVI, there were little changes on the Se(VI) removal by the varied concentration of the Fe(II). From these results, we found that Fe(II) ion plays an accelerator for the reduction of Se(VI) by ZVI with the stoichiometric balance of 1.4 (=nFe(2+)/nSe(6+)). Under anoxic conditions, the batch test revealed about 10% removal of the Se(VI), indicating that the presence of dissolved oxygen increased the kinetics of Se(VI) removal due to the Fe(II)-containing oxides on the ZVI, as analyzed by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) spectra also showed that the reductive process of Se(VI) to Se(0)/Se(-II) occurred in the presence of the both ZVI and Fe(II). The final product of iron corrosion was lepidocrocite (γ-FeOOH), which acts as an electron transfer barrier from Fe(0) core to Se(VI). Therefore, the addition of Fe(II) enhanced the reactivity of ZVI through the formation of iron oxides (magnetite) favoring electron transfer during the removal of Se(VI), which was through the exhaustion of the Fe(0) core reacted with Se(VI).

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Section: Effect Of Fe(ii) On the Removal Of Se(vi) By Zvimentioning

confidence: 99%

“…Our previous study reported that a low Se(VI) concentration, low pH, and the presence of dissolved oxygen increased the kinetics of Se(VI) removal. The reduction capacity and iron corrosion coating of ZVI have been found to depend on the Se(VI) concentration (i.e., the Se(VI)/ZVI ratio) (Yoon et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Selenate removal by zero-valent iron in oxic condition: the role of Fe(II) and selenate removal mechanism

Yoon

Bang²,

Kim

et al. 2015

Environ Sci Pollut Res

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“…Se VI was tested as redox-sensitive species to be reductively precipitated by Fe 0 . This effort was supported by an impressive number of modern analytical tools, using both bulk and surface methods [15,109,110,114,115]. Related studies tested several types of ) like in the Harza Process and (ii) characterizing the intrinsic reactivity of individual materials [38].…”

Section: Lessons From the Fe 0 /Se Systemmentioning

confidence: 99%

“…With the advent of Fe 0 reactive walls (permeable reactive barriers), the Fe 0 /Se system was 'rediscovered' and (mostly independently) intensively investigated over the past 17 years [15,40,102,103,[104][105][106][107][108][109][110][111][112][113]. Se VI was tested as redox-sensitive species to be reductively precipitated by Fe 0 .…”

Section: Lessons From the Fe 0 /Se Systemmentioning

confidence: 99%

Rescuing Fe0 remediation research from its systemic flaws

Noubactep¹,

Makota²,

Bandyopadhyay³

2017

Res Rev Insights

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The well-accepted assumption of metallic iron (Fe 0 ) acting as electron donor for environmental remediation has created an unstable domain of knowledge for the past 23 years. This assumption is discouraging some outstanding and prospective scientists from correctly interpreting their experimental results. Such a situation is a recipe for long-term decline. The critical situation cannot be solved with simplistic approaches. It is now imperative to develop an understanding to defend the difficulties of this assumption and re-orient Fe 0 mediated remediation research as a whole.

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“…At low concentrations of selenium in water, selenium is removed through surface adsorption and chemical reduction [9] [10]. The reaction mechanism is as follows [9] …”

Section: Introductionmentioning

confidence: 99%

Evaluating Effectiveness and Permanence of Selenium Treatment in a Solid Matrix via Aqueous-Mediated Zero Valent Iron Reaction

Grieco¹,

Singer²,

Bement³

2017

JEP

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Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fuel and subsequent combustion, metal ore refining and processing, and agricultural irrigation. Of concern is removing selenium liquid matrices and immobilizing it from leachable solid matrices. Chemical reduction and stabilization using zero valent iron (ZVI) is applicable to both concerns. The solid matrix case study is applicable to ash ponds solids or industrial bag house dust solids. This paper presents data for treatment and stabilization of selenium within a solid matrix using ZVI. The methodology uses an aqueous mediate reaction to promote a stable solid matrix of non-leachable selenium. The paper describes matrix challenges and key variables that effected successful treatment. Testing with simulated and real bag house dust solids were used to establish data to support the permeance of the reaction. The data show that ZVI converts ionic selenium to a zero valent state in the solid matrix. It was also recognized that a fraction of ionic selenium may fail to react with the ZVI, but the results show that despite the presence of the unreacted ionic selenium, the toxicity characteristic leachate procedure (TCLP) results following treatment do not exceed the 1 mg/L hazardous waste criteria.

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Reduction and adsorption mechanisms of selenate by zero-valent iron and related iron corrosion

Cited by 139 publications

References 40 publications

Selenate removal by zero-valent iron in oxic condition: the role of Fe(II) and selenate removal mechanism

Selenate removal by zero-valent iron in oxic condition: the role of Fe(II) and selenate removal mechanism

Rescuing Fe0 remediation research from its systemic flaws

Evaluating Effectiveness and Permanence of Selenium Treatment in a Solid Matrix via Aqueous-Mediated Zero Valent Iron Reaction

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