Effect of dissolved oxygen on the radiolytic conversion of nitrate ions in aqueous solutions in the presence of formate

Bludenko, A. V.; Makarov, Igor; Пономарев, А. В.

doi:10.1070/mc2002v012n04abeh001594

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…The hydrated electron and H • are capable of fast reduction reactions with inorganic cations and anions formed by atoms of the highest oxidation state, while the HO • radical interacts effectively with metal cations in the lowest oxidation state and with most inorganic anions. ,,− Consequently, effective reductive neutralization of inorganic ions dominates in water in the presence of organic compounds playing the role of HO • scavengers. ,,,− But sometimes, especially in dilute systems, reducing and oxidizing particles can give rise to opposite transformations and thereby provoke the regeneration of the pollutant. In order to regulate the contribution of oxidizing and reducing particles as well as to completely convert the reducing particles to oxidizing ones, some simple approaches are used in practice (Figure S5).…”

Section: Selection and Interconversion Of Redox Intermediatesmentioning

confidence: 99%

The Green Method in Water Management: Electron Beam Treatment

Пономарев

Ершов

2020

Environ. Sci. Technol.

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During the prebiotic era, radiolytic transformations in the oceans played a key role in purifying water from toxic impurities and, thus, played a role in the formation of the aquatic environment of our planet, making it suitable for the emergence of life. Today, the planet again faces the challenge of how to provide people with clean water. Therefore, it is reasonable to look back at past historical stages and again consider the possibility of neutralizing pollutants in water by means of radiolysis, which has already been tested by time. Modern radiolytic treatments can be much faster and safer thanks to the advent of powerful electron accelerators and high-rate electron beam treatment (ELT) of water and wastewater. Radiolytic treatment of water using accelerated electrons corresponds to the essence of advanced oxidative technologies and green chemistry. The ELT of water instantly generates a high concentration of short-lived radicals that can quickly neutralize and decompose chemical and bacterial pollutants. Due to the ability of accelerated electrons to penetrate into a substance, ELT provides the decomposition of both dissolved and suspended pollutants. The cleaning effect of ELT is due to the ability to inactivate toxic and chromophore functional groups, transform impurities into an easily removable form, damage the DNA of microorganisms and their spore forms, and increase the biodegradability of organic impurities. The use of ELT in water treatment provides significant savings in chemical reagents, thereby improving quality and reducing the number of cleaning steps. The compactness, high degree of automation of the equipment used, energy efficiency, high productivity, and excellent compatibility with traditional water treatment methods are important advantages of ELT. Unlike conventional chemicals, the excess radicals generated in the ELT process are converted back to water and hydrogen; thus, the chemical and corrosive activity of water does not increase. Equipping research institutes with electron accelerators, developing cheaper accelerators, and granting government support for pilot projects are key conditions for introducing ELT into water treatment practice.

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Section: Selection and Interconversion Of Redox Intermediatesmentioning

confidence: 99%

The Green Method in Water Management: Electron Beam Treatment

Пономарев

Ершов

2020

Environ. Sci. Technol.

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“…Borohydride is another reagent that has been studied and proven to reduce NO 3 -under neutral or basic conditions but it requires the addition of catalysts such as Cu or Zn . Formate and organic substances were also tested to form complex reactions that require the presence of initiators and catalysts (Bludenko et al 2002). Organic compounds (e.g., methanol) were used to reduce NO 3 -through a photochemical process but NO 3 -removal was only achieved under very high temperatures and pressures (Sato et al 1996).…”

Section: Nitrate (Nomentioning

confidence: 99%

Nitrate removal from water using UV-M/S2O4 2− advanced reduction process

Bensalah

Nicola

Abdel‐Wahab

2013

Int. J. Environ. Sci. Technol.

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In this work, a new process called advanced reduction process (ARP) was used for nitrate removal from water. This ARP process combines sodium dithionite as reducing agent with ultraviolet irradiation using medium pressure lamps (UV-M) as an activating method. Experimental results showed that UV-M/S 2 O 4 2-process achieved almost complete removal of nitrate from aqueous solutions containing 25 mg NO 3 -/L using stoichiometric dose of dithionite of 68.8 mg/L at neutral pH conditions. Analysis of final products and material balance confirmed that NO 3 -ions were reduced to ammonium with formation of nitrite as intermediates in addition to the formation of small amounts of volatile species, mainly ammonia and nitrogen gas. Effects of certain experimental parameters including dithionite dose, initial pH, initial nitrate concentration, and UV light source on the kinetics and efficiency of nitrate reduction were evaluated. Increasing dithionite dose augmented the rate of nitrate reduction and enhanced the efficiency of ARP process. Dithionite doses higher than stoichiometric ratios led to complete removal of nitrate in shorter reaction time. UV-M/S 2 O 4 2-process was found to be effective only under neutral pH or alkaline conditions, and its removal efficiency is negligible in acidic medium (pH \ 4). Irradiation with UV-M was more effective than low pressure or narrow band lamps. These results can be attributed to the contribution of several mechanisms for nitrate reduction to ammonium. These include the following: direct photolysis, chemical reduction of nitrate dithionite, and mediated reduction of nitrate by free reducing radicals.

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