Reaction of zero-valent magnesium with water: Potential applications in environmental remediation

Lee, Giehyeon; Park, Jaeseon

doi:10.1016/j.gca.2012.10.031

Cited by 27 publications

(32 citation statements)

References 57 publications

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“…The NO 3 − reduction takes place according to several reactions that can simultaneously occur and involve different chemical species. In aqueous solutions the metallic magnesium is oxidized by H 2 O, O 2 and H + according the following reactions [32,37]:…”

Section: Reaction Mechanisms and Characteristics Of Exhausted Materialsmentioning

confidence: 99%

Chemical Denitrification with Mg0 Particles in Column Systems

2020

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The removal of nitrate from aqueous environments through zero-valent metallic elements is an attractive technique that has gained increasing interest in recent years. In comparison to other metallic elements, zero-valent magnesium (ZVM) has numerous beneficial aspects. Nevertheless, the use of Mg0 particles for nitrate reduction in column systems has not been investigated yet. To overcome the lack of research, in the present study, a wide experimental activity was carried out to develop a chemical denitrification process through ZVM in batch column equipment. Several tests were executed to evaluate the effects of recirculation hydraulic velocity, pH, Mg0 amount, N-NO3− initial concentration and temperature on the process performance. The results show that the process efficiency is positively influenced by the recirculation velocity increase. In particular, the optimal condition was detected with a value of 1 m/min. The process pH was identified as the main operating parameter. At pH 3, abatements higher than 86.6% were reached for every initial nitrate concentration tested. In these conditions, nitrogen gas was detected as the main reaction product. The pH increase up to values of 5 and 7 caused a drastic denitrification decline with observed efficiencies below 26%. At pH 3, the ratio (RMN) between Mg0 and initial nitrate amount also plays a key role in the treatment performance. A characteristic value of about RMN = 0.333 gMg0/mgN-NO3− was found with which it is possible to reach the maximum reaction rate. Unexpectedly, the process was negatively affected by the increase in temperature from 20 to 40 °C. At 20 °C, the material showed satisfactory denitrification efficiencies in subsequent reuse cycles. With the optimal RMN ratio, removals up to 90% were detected by reusing the reactive material three times. By means of a kinetic analysis, a mathematical law able to describe the nitrate abatement curves was defined. Moreover, the relation between the observed kinetic constant and the operating parameters was recognized. Finally, the reaction pathways were proposed and the corrosion reaction products formed during the treatment were identified.

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Section: Reaction Mechanisms and Characteristics Of Exhausted Materialsmentioning

confidence: 99%

Chemical Denitrification with Mg0 Particles in Column Systems

2020

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“…Therefore, there is a need to identify low cost, abundant, readily available, non-toxic reactive materials that are able to efficiently remove pollutants under ambient conditions. In this regard, zero-valent Mg (ZVM) represents a valid reductant for potential applications in the treatment of aqueous solutions [4,[29][30][31][32]. Indeed, ZVM is an environmentally friendly metal, which is characterized by a higher reduction potential (−2.363 V) compared to Fe 0 (−0.44 V) [4].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis and Modeling of Nitrate Removal through Zero-Valent Magnesium Particles

Siciliano

Curcio

Limonti

2019

Water

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The pollution of water by nitrates represents an important environmental and health issue. The development of sustainable technologies that are able to efficiently remove this contaminant is a key challenge in the field of wastewater treatment. Chemical denitrification by means of zero-valent metallic elements is an interesting method to reduce the oxidized forms of nitrogen. Compared to other metallic reactants, zero-valent magnesium (ZVM) has many profitable aspects, but its use for nitrate removal has scarcely been investigated. In the present work, several batch tests were conducted to examine the concurrent effects of pH, initial nitrate concentration and Mg0 quantity on process performance. The experimental results proved that at pH 3, for a given initial nitrate concentration, the dose of ZVM largely influences process efficiency. In particular, with a ratio between Mg0 and initial N-NO3− amount (Mg/NNi) of 0.33 g/mg, it is possible to obtain complete denitrification within 30 min. Beyond this ratio, no further improvement of treatment was observed. The experiments allowed us to identify the nitrogen forms produced during the treatment. Nitrogen gas was generally the main reaction product, but the trends of the different compounds (NO3−, NO2−, NH4+ and N2) notably changed in response to the modification of operating parameters. Moreover, the results demonstrated that, in a highly acidic environment, when treating solutions with a low nitrate concentration, process performances are unsatisfactory even when using a high Mg/NNi ratio. By increasing the process pH to 5 and 7, a significant denitrification decline occurred. Furthermore, at these pH levels, the enhancement of nitrate concentration caused a progressive process deterioration. Through detailed analysis of experimental results, reactions kinetics and new mathematical equations, able to describe the trends of different nitrogen forms, have been defined. Moreover, reactions pathways have been proposed. Finally, the characterization of exhausted material allowed us to identify the corrosion products formed during the treatment.

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“…In our paper, we did not interpret the results of McMurray et al [2] and Swiatkowska et al [1] other than to repeat their conclusions that there was no evidence for unipositive Mg. It can also now be noted that the recent work of Frankel et al [4] can be added to this list, as can the recent work of Souto et al [5] and Lee et al [12]. We also remind readers that no one has yet managed to isolate any compounds containing Mg + , nor has any spectroscopic data ever been published which confirms even the transient appearance of such a species.…”

Section: Commentmentioning

confidence: 67%

“…We don't believe that this is actually the forum to debate the work of Shi and Atrens, which is best done by a broader revisiting by interested readers in the wider literature, who we believe can use their own interpretation [1][2][3][4][5][6][7][8][9][10][11][12].…”

mentioning

confidence: 99%

Response to comments from Shi and Atrens on the paper “Observations of the galvanostatic dissolution of pure magnesium”

2013

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Abstract:A consolidated response is made here to address the comments of Shi and Atrens concerning the manuscript "Observations of the galvanostatic dissolution of pure magnesium". We provide discussion to indicate that the claims made by Shi and Atrens are invalid from an electrochemical and logical perspective, and therefore there is no basis for Shi and Atrens claim that our work provides evidence for Mg + .

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Reaction of zero-valent magnesium with water: Potential applications in environmental remediation

Cited by 27 publications

References 57 publications

Chemical Denitrification with Mg0 Particles in Column Systems

Chemical Denitrification with Mg0 Particles in Column Systems

Experimental Analysis and Modeling of Nitrate Removal through Zero-Valent Magnesium Particles

Response to comments from Shi and Atrens on the paper “Observations of the galvanostatic dissolution of pure magnesium”

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