A new procedure for the spectrophotometric determination of nitrogen(II) oxide in solutions

Pukhovskaya, S. G.; Guseva, L. Zh.; Макаров, С. В.; Naidenko, E. V.

doi:10.1007/s10809-005-0037-6

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…(Siddiqui et al, 1996). The oxidizing free radical (OH ) and the reducing species (H and eaq ) are the most reactive products of this reaction and generally control the rate of degradation observed during E-beam treatment.…”

Section: Activation Methodsmentioning

confidence: 99%

“…This free radical anion is a strong reductant with a reported standard reduction potential of -0.66 V (Mayhew, 1978). Dithionite has an absorption peak in the ultraviolet near 315 nm (Ohlsson et al, 1986;McKenna et al, 1991;Pukhovskaya et al, 2005), so irradiation near this wavelength can provide energy to break the weak S-S bond. Although sulfite (SO 3 2 -) is a particular anion, it will be used as a general term to describe the group that includes sulfurous acid (H 2 SO 3 ), bisulfite (HSO 3 -), and sulfite (SO 3 2 -).…”

Section: Reducing Agentsmentioning

confidence: 99%

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Advanced Reduction Processes: A New Class of Treatment Processes

Vellanki

Batchelor

Abdel‐Wahab

2013

Environmental Engineering Science

177

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A new class of treatment processes called advanced reduction processes (ARPs) is proposed. ARPs combine activation methods and reducing agents to form highly reactive reducing radicals that degrade oxidized contaminants. Batch screening experiments were conducted to identify effective ARPs by applying several combinations of activation methods (ultraviolet light, ultrasound, electron beam, and microwaves) and reducing agents (dithionite, sulfite, ferrous iron, and sulfide) to degradation of four target contaminants (perchlorate, nitrate, perfluorooctanoic acid, and 2,4 dichlorophenol) at three pH-levels (2.4, 7.0, and 11.2). These experiments identified the combination of sulfite activated by ultraviolet light produced by a low-pressure mercury vapor lamp (UV-L) as an effective ARP. More detailed kinetic experiments were conducted with nitrate and perchlorate as target compounds, and nitrate was found to degrade more rapidly than perchlorate. Effectiveness of the UV-L/sulfite treatment process improved with increasing pH for both perchlorate and nitrate. We present the theory behind ARPs, identify potential ARPs, demonstrate their effectiveness against a wide range of contaminants, and provide basic experimental evidence in support of the fundamental hypothesis for ARP, namely, that activation methods can be applied to reductants to form reducing radicals that degrade oxidized contaminants. This article provides an introduction to ARPs along with sufficient data to identify potentially effective ARPs and the target compounds these ARPs will be most effective in destroying. Further research will provide a detailed analysis of degradation kinetics and the mechanisms of contaminant destruction in an ARP.

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Section: Activation Methodsmentioning

confidence: 99%

Section: Reducing Agentsmentioning

confidence: 99%

Advanced Reduction Processes: A New Class of Treatment Processes

Vellanki

Batchelor

Abdel‐Wahab

2013

Environmental Engineering Science

177

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“…The concentration of nitrogen monoxide in solutions was determined spectrophotometrically using a special procedure. 15 Purity of porphyrins 1-4 was checked by TLC on aluminum plates with the 0.5 mm fixed layer of silica gel F 254 (Merck) with a CHCl 3 -EtOH eluate (ratio of solvents was chosen depending on individual properties of porphyrins) and by the electronic absorption spectra, which corresponded to literature data. [16][17][18] …”

Section: Methodsmentioning

confidence: 99%

Coordination compounds of cobalt porphyrins with nitrogen monoxide

2007

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Complex formation of NO and the NO 2 -ion with cobalt porphyrins bearing various substituents in the porphyrin macrocycle, viz., tetraphenylporphine (1), β octabromo meso tetraphenylporphyrin (2), protoporphyrin IX (3), and 5,10,15,20 tetra(4N carboxymethylene pyridyl)porphyrin tetrabromide (4), was studied. The stability constants of the nitrosyl and nitrite extracomplexes in water and in ethanol were determined. Porphyrin 4 forms the most stable extracomplexes. Nitrogen monoxide is produced by enzymatic systems in mammals and acts as a versatile regulator of metabolic processes. 1-3 Nitrogen monoxide is found 4,5 to be an endogenic vasodilator and neurotransmitter and oppresses thrombocyte aggregation; the superoxide radical and NO during oxidative stress act in conjugation.Nitrogen monoxide is produced in biological systems by NO synthases from L arginine, which is classified as an enzyme forming the NO • free radical and citrulline as a by product. 6 In the organism nitrogen monoxide is rapidly oxidized to stable end products, NO 2 -and NO 3 -ions. The nitrite ion in vivo oxidizes oxyhemoglobin and cata lyzes reactions involving NO. The mechanism of toxic effect of nitrites is mainly attributed to the oxidation of hemoglobin to methemoglobin accompanied by the vio lation of oxygen transport to tissues due to which hemic hypoxia is developed. Nitrogen monoxide can coordinate to thiols, sulfur-iron proteins of plasma, secondary amines, and hemoglobin and be consumed in reactions with oxygen, superoxide radicals, and hemoglobin. 5-8 Therefore, non heme models of iron containing proteins are being developed and their nitrosyl complexes are un der study. 9 However, the single compensatory adjustment form of NO depositing and utilization is complex forma tion with hemoglobin that occurs via axial coordination on the protoheme. 10 Therefore, investigation of binding (axial coordination) processes of nitrogen monoxide and its metabolite (nitrite ion) by metal porphyrins in solu tions is key for understanding of the essence of biological processes involving NO.In the present work, we studied the equilibrium of formation of the axial NO and NO 2 -complexes with Co II porphyrins of different structural types: tetraphe nylporphine (1), β octabromo meso tetraphenylpor phyrin (2), protoporphyrin IX (3), and 5,10,15,20 tetra(4N carboxymethylenepiridyl)porphyrin tetrabro R = H (1), Br (2)

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“…Dithionite consists of a structure with a long and weak SeS bond, which can easily be broken into two sulphur dioxide radical anions (SO 2 % − ) with a standard reduction potential (E 0 ) of −0.66 V [35]. The maximum absorption peak is obtained at a wavelength of 315 nm, which is optimal to break the SeS bond to yield radicals [21,36]. At the experimental wavelength of 253.7 nm employed in this study, the formation of SO 2 % − will, however, not be optimal, resulting in a lower degradation efficiency of 2,4-DCP.…”

Section: Type Of Reductive Agentmentioning

confidence: 99%

Effects of process variables and kinetics on the degradation of 2,4-dichlorophenol using advanced reduction processes (ARP)

Cabooter

Dewil

2018

Journal of Hazardous Materials

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This study aims at investigating the efficiency and kinetics of 2,4-DCP degradation via advanced reduction processes (ARP). Using UV light as activation method, the highest degradation efficiency of 2,4-DCP was obtained when using sulphite as a reducing agent. The highest degradation efficiency was observed under alkaline conditions (pH = 10.0), for high sulphite dosage and UV intensity, and low 2,4-DCP concentration. For all process conditions, first-order reaction rate kinetics were applicable. A quadratic polynomial equation fitted by a Box-Behnken Design was used as a statistical model and proved to be precise and reliable in describing the significance of the different process variables. The analysis of variance demonstrated that the experimental results were in good agreement with the predicted model (R = 0.9343), and solution pH, sulphite dose and UV intensity were found to be key process variables in the sulphite/UV ARP. Consequently, the present study provides a promising approach for the efficient degradation of 2,4-DCP with fast degradation kinetics.

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A new procedure for the spectrophotometric determination of nitrogen(II) oxide in solutions

Cited by 6 publications

References 7 publications

Advanced Reduction Processes: A New Class of Treatment Processes

Advanced Reduction Processes: A New Class of Treatment Processes

Coordination compounds of cobalt porphyrins with nitrogen monoxide

Effects of process variables and kinetics on the degradation of 2,4-dichlorophenol using advanced reduction processes (ARP)

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