Rapid magnetic removal of aqueous heavy metals and their relevant mechanisms using nanoscale zero valent iron (nZVI) particles

Huang, Pengpeng; Ye, Zhengfang; Xie, Wei; Chen, Qi; Li, Jing; Xu, Zhencheng; Yao, Maosheng

doi:10.1016/j.watres.2013.01.054

Cited by 210 publications

(72 citation statements)

References 30 publications

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“…It is known that water aging under aerobic conditions, as in the present case, leads to an increase in the SSA [29] and that the SSA could increase during interaction with pollutants [11,39]. It must be taken into account that nZVI obtained by the gas reduction process has a different reaction mechanism to nZVI particles obtained by borohydride reduction and a smaller increase in SSA would be expected [27,38].…”

Section: Characterization Of Un-activated and Activated Particlesmentioning

confidence: 72%

Activation process of air stable nanoscale zero-valent iron particles

Ribas

Černík

Benito

et al. 2017

Chemical Engineering Journal

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Nanoscale Zero Valent Iron (nZVI) represents a promising material for subsurface water remediation technology. However, dry, bare nZVI particles are highly reactive, being pyrophoric when they are in contact with air. The current trends of nZVI manufacturing lead to the surface passivation of dry nZVI particles with a thin oxide layer, which entails a decrease in their reactivity. In this work an activation procedure to recover the reactivity of air-stable nZVI particles is presented. The method consists of exposing nZVI to water for 36 hours just before the reaction with the pollutants. To assess the increase in nZVI reactivity based on the activation procedure, three types of nZVI particles with different oxide shell thicknesses have been tested for Cr(VI) removal. The two types of air-stable nZVI particles with an oxide shell thickness of around 3.4 and 6.5 nm increased their reactivity by a factor of 4.7 and 3.4 after activation, respectively. However, the pyrophoric nZVI particles displayed no significant improvement in reactivity. The improvement in reactivity is related mainly to the degradation of the oxide shell, which enhances electron transfer and leads secondarily to an increase in the specific surface area of the nZVI after the activation process. In order to validate the activation process, additional tests with selected chlorinated compounds demonstrated an increase in the degradation rate by activated nZVI particles.

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Section: Characterization Of Un-activated and Activated Particlesmentioning

confidence: 72%

Activation process of air stable nanoscale zero-valent iron particles

Ribas

Černík

Benito

et al. 2017

Chemical Engineering Journal

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“…Fig. 9(a) showed the Fe 2p peaks at the binding energies of 710.1 (Fe 2p 3/2 ) and 724.1 eV (Fe 2p 1/2 ), with a shakeup satellite at 719.0 eV [57,58]. The satellite signal at 719.0 eV can be attributed to Fe in Fe 2 O 3 [58].…”

Section: Xps Analysismentioning

confidence: 96%

Studies on the optimum conditions using acid-washed zero-valent iron/aluminum mixtures in permeable reactive barriers for the removal of different heavy metal ions from wastewater

Han

Cheng

et al. 2016

Journal of Hazardous Materials

145

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“…The discrepancies may arise from different initial Cd(II) concentrations, temperature, and water chemistry such as pH (Klimkova et al, 2011;Boparai et al, 2013;Liu et al, 2008), and concentrations of dissolved oxygen Reinsch et al, 2010), phosphate (Reinsch et al, 2010;Su and Puls, 2004), and nitrate Reinsch et al, 2010). According to previous studies (Li and Zhang, 2007;Boparai et al, 2011;Huang et al, 2013), X-ray photoelectron spectroscopy (XPS) analysis indicated that Cd(II) immobilization by nZVI was mainly through adsorption. However, reduction of Cd(II) to Cd(0) may also occur due to its slightly more positive standard electrode potential (E 0 , E 1 0 ¼ À0.403 V) than Fe (E 2 0 ¼ À0.447 V) (Lide, 2004).…”

Section: Introductionmentioning

confidence: 93%

Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles

et al. 2014

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a b s t r a c tNanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the cocontaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe 3 O 4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ! 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.© 2014 Elsevier Ltd. All rights reserved. Available online at www.sciencedirect.com ScienceDirect journal homepage: www.else vier.com/locate /wa tres w a t e r r e s e a r c h 6 3 ( 2 0 1 4 ) 1 0 2 e1 1 1http://dx

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Rapid magnetic removal of aqueous heavy metals and their relevant mechanisms using nanoscale zero valent iron (nZVI) particles

Cited by 210 publications

References 30 publications

Activation process of air stable nanoscale zero-valent iron particles

Activation process of air stable nanoscale zero-valent iron particles

Studies on the optimum conditions using acid-washed zero-valent iron/aluminum mixtures in permeable reactive barriers for the removal of different heavy metal ions from wastewater

Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles

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