Chemical processes on active carbon surface: A new example of nitrogen fixation

Vorob'ev-Desyatovskii, N. V.; Ibragimova, R. I.; Gordeev, S. K.; Nikolaev, B. P.

doi:10.1134/s107036320606017x

Cited by 8 publications

(15 citation statements)

References 27 publications

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“…As can be seen, Carboxen 572 had the smoothest surface with the least amount of surface defects, while AqC and PSC particles showed considerable microdefects on their surfaces which may interact with dissolved oxygen to generate ROS. 47 Since these two carbons have higher NDMA yield than F400 or Carboxen 572, carbon surface defects may indeed be responsible for reactions involved in nitrosamine formation.…”

Section: ' Results and Discussionmentioning

confidence: 99%

N-Nitrosamines Formation from Secondary Amines by Nitrogen Fixation on the Surface of Activated Carbon

Padhye

Hertzberg

Yushin

et al. 2011

Environ. Sci. Technol.

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Our previous study demonstrated that many commercial activated carbon (AC) particles may catalyze transformation of secondary amines to yield trace levels of N-nitrosamines under ambient aerobic conditions. Because of the widespread usage of AC materials in numerous analytical and environmental applications, it is imperative to understand the reaction mechanism responsible for formation of nitrosamine on the surface of ACs to minimize their occurrence in water treatment systems and during analytical methods employing ACs. The study results show that the AC-catalyzed nitrosamine formation requires both atmospheric oxygen and nitrogen. AC's surface reactive sites react with molecular oxygen to form reactive oxygen species (ROS), which facilitate fixation of molecular nitrogen on the carbon surfaces to generate reactive nitrogen species (RNS) likely nitrous oxide and hydroxylamine that can react with adsorbed amines to form nitrosamines. AC's properties play a crucial role as more nitrosamine formation is associated with carbon surfaces with higher surface area, more surface defects, reduced surface properties, higher O(2) uptake capacity, and higher carbonyl group content. This study is a first of its kind on the nitrosamine formation mechanism involving nitrogen fixation on AC surfaces, and the information will be useful for minimization of nitrosamines in AC-based processes.

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Section: ' Results and Discussionmentioning

confidence: 99%

N-Nitrosamines Formation from Secondary Amines by Nitrogen Fixation on the Surface of Activated Carbon

Padhye

Hertzberg

Yushin

et al. 2011

Environ. Sci. Technol.

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“…The ability of AC surfaces to react with oxygen to generate ROS has been well recognized and is related to surface defects (66). ROS generated or carbene centers created by reactions on carbon surfaces could be responsible for nitrogen fixation by reacting with dissolved N 2 to form RNS like N 2 O or diazo intermediates (67,68). Reductive transformation promoted by AC surfaces may convert N 2 O to yield NH-containing species such as Н 2 N 2 O, NН 2 OH and ammonia (69).…”

Section: Reaction Mechanismsmentioning

confidence: 99%

Catalytic Impact of Activated Carbon on the Formation of Nitrosamines from Different Amine Precursors

Huang

Padhye

Wang

2013

ACS Symposium Series

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N-nitrosamines are emerging carcinogenic contaminants and can be generated from transformation of amines. Activated carbon (AC) materials with micro-and nano-porous structures are commonly used for extraction of nitrosamines in water, and for removal of micropollutants in water and wastewater treatment. Recent research demonstrated that AC materials may catalyze transformation of amine precursors to yield nitrosamines under environmentally relevant conditions. AC catalyzes the formation of nitrosamine primarily via two different types of reactions: (I) catalyzing nitrosation of amine with nitrite or nitrate to yield nitrosamine, and (II) catalyzing oxidation of amine in the presence of molecular oxygen and nitrogen to generate nitrosamine. The AC-catalyzed nitrosamine formation is highly influenced by AC's properties, amine precursors' structures and reaction conditions. Considering the widespread usage of AC in environmental and industrial applications, a better understanding of the catalytic impact of AC on nitrosamine formation is critical to minimize undesirable nitrosamine formation where co-existence of AC and amine precursors is encountered.

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“…Presumably, this concentration can be considered quasi-stationary because activated carbons are catalysts for H 2 O 2 decomposition [17,18]. It should be noted that the formation of hydrogen peroxide in solution is not necessarily associated with the occurrence of reaction (2), but may result from the appearance of superoxide anion radicals O 2 -• in an aqueous solution contacting with activated carbon and dissolved atmospheric oxygen and further transformations of these species [19].…”

mentioning

confidence: 99%

“…It is known that activated carbons commonly contain in their composition a very small number of nitrogen atoms bound with the matrix. Even in the case when a starting sample of activated carbons did not contain these atoms at all, dissolved atmospheric nitrogen is fi xed on carbene-like centers in water and aqueous solutions without addition of oxidizing agents (H 2 O 2 ) [19,23,24]. A part of the surface nitrogen-containing fragments being formed possess basic properties, which may also lead to an ion exchange of OHanions bound with nitrogen-containing anion centers formed in contact with water for [Au(CN) 2 ]anions.…”

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Use of ion-exchange resins to deal with the effect of preg-robbing of gold in the course of cyanide leaching

Fedyukevich¹,

Kubyshkin²,

Блохин

et al. 2015

Russ J Appl Chem

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Possibility of using strongly basic anion exchange resin of MINIX brand and weakly basic anion exchange resin Purogold S992 brand in the high-temperature-caustic conditioning (HiTeCC) technological process for diminishing the loss of gold via adsorption on natural organic carbon-containing substances (pregrobbing phenomenon) in the course of cyanide leaching was studied. It was shown that the strongly basic anion exchanger MINIX has a higher affi nity for the anion [Au(CN) 2 ] -, compared with the microporous activated carbon WSC-207C-GR. As a result, the adsorbed dicyanoaurate(I) anion is transferred from the activated carbon to the ion-exchange resin. Reasons for binding of the dicyanoaurate(I) anion with active centers of activated carbons are considered, based on the fact that the adsorbent contains carbene-like carbon atoms. The existence of paramagnetic centers belonging to carbon atoms in the activated carbon was demonstrated by the EPR method. The suggested concept was used to diminish the loss of gold via partial oxidation of metallic gold in autoclave processing of pyrite-and arsenopyrite-containing concentrates.

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Chemical processes on active carbon surface: A new example of nitrogen fixation

Cited by 8 publications

References 27 publications

N-Nitrosamines Formation from Secondary Amines by Nitrogen Fixation on the Surface of Activated Carbon

N-Nitrosamines Formation from Secondary Amines by Nitrogen Fixation on the Surface of Activated Carbon

Catalytic Impact of Activated Carbon on the Formation of Nitrosamines from Different Amine Precursors

Use of ion-exchange resins to deal with the effect of preg-robbing of gold in the course of cyanide leaching

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