Alpha-Induced Decomposition of Ammonia. II. Effects of Variations in Intensity and Pressure

Burtt, Benjamin P.; Zahlan, A. B.

doi:10.1063/1.1743418

Cited by 12 publications

(7 citation statements)

References 8 publications

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“…The initial yield for the disappearance of 0 2 must be equal to g(H)+g(OH) through eqn. ( 16) and (17), but the value we observe is the net result of these reactions and those in which 0 2 is regenerated, e.g., (18), (23, (23, (24) and the dimerization of hydroperoxy radicals.…”

Section: P R I M a R Y Processes I N Radiolysis Of Water V A P O U Rmentioning

confidence: 66%

The ?-radiolysis of water vapour in the presence of NH3 and O2

Anderson¹,

Knight²,

Winter³

1966

Trans. Faraday Soc.

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Measurements of H2 production from pure water vapour as a function of dose indicate that, like liquid water, it is essentially stable to y radiation. The net yield of H2 is very low leading to a mean integral value of G(H+0007 but the amount of H2 obtained depends critically on the care taken in cleaning the cells and admitting the water, and it is concluded that previously-published yields are all integral values obtained under a variety of conditions. Measurement of the primary yields in the presence of N H 3 and of NH3fO2 gives g(0H) = 6.650.2, g(H) = 5-7f0.2, g(H2) = 047f0.01, but no distinction can be made between yields of electrons and H atoms in this work.Primary processes of ionization and charge recombination are considered in view of earlier postulates, together with physical evidence which demonstrates the stability of ion clusters in water vapour even at low pressures. It is suggested that, under certain conditions in the vapour phase, charge neutralization of the H3Of ion leads to the same yield of radicals as in liquid water.Published data on the radiolysis of water vapour are sparse and contradictory, both in the absence and presence of added scavengers. Values for G(H2) from the radiolysis of pure water vapour vary from 0.014 to 5.9,1-5 while the value for the radical pair yield g(H)* = 11.7, obtained by Firestone 3 in studies of the Dz/H20 exchange reaction, has been challenged by Baxendale and Gilbert,4 who report g(HJ = 8 k0.7 from measurements in the presence of organic scavengers. These values are of prime importance in understanding the radiolysis of water vapour, and we have extended the previous work by measurements both in pure water vapour and on the addition of NH3 and 0 2 . EXPERIMENTAL PREPARATIONSamples were irradiated in Pyrex cells ; the cell volumes varied from 100 to 1000 ml. The cells carried a B10 glass joint with a fragile tip for reopening under vacuum. Water samples were prepared in separate tubes containing a septum break seal, which were joined to the cell by fusion. Water was admitted to the main irradiation cell by breaking the septum with a glass rod before irradiation. These water tubes were filled on an all-glass mercury-free vacuum line in which the water vapour was not allowed to come into contact with any greased stopcocks during addition or transfer. An all-glass valve was designed for use with this system. The amount of water distilled into each water tube was monitored by measuring the difference in height of water in a precision-bore capillary after filling and sealing each tube. The metering tube was filled with water, which was first boiled to remove most of the dissolved gases, and then subjected to several cycles of freezing at -78"C, pumping to 10-6 mm Hg and thawing. Water tubes were evacuated to 10-6 mm Hg before distilling water into them and again before they were sealed. This technique of admitting water separately was developed because of difficulty experienced in adding 0 2 * Primary yields are written as g(x) and experimental yields as G(x).

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Section: P R I M a R Y Processes I N Radiolysis Of Water V A P O U Rmentioning

confidence: 66%

The ?-radiolysis of water vapour in the presence of NH3 and O2

Anderson¹,

Knight²,

Winter³

1966

Trans. Faraday Soc.

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“…It means that the photochemical formation of hydrazine begins by the absorption of TiO 2 particles. It is well known that the electronically excited TiO 2 by the absorption of UV light is created as the geminated form on the surface of the TiO 2 as presented in equation (1).…”

Section: Resultsmentioning

confidence: 99%

Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂

2008

Bulletin of the Korean Chemical Society

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Ammonia is produced in huge quantities worldwide not only by commercial chemical factories but by decaying vegetation, garbage, even decomposition of the other protein materials. Ammonia with foul odor causes a serious environmental pollution in the atmosphere. Therefore, the decomposition of ammonia has attracted considerable attention in respect to environmental pollution of the atmosphere.Earlier investigation on the decomposition of ammonia using a light was performed by means of radiolysis 1,2 and photolysis 3-8 in the gaseous state. Ammonia molecules are incorporated into water droplets and form liquid aerosols which can range in diameter with nanoscale particle.9 Recently, we have reported on the photochemical decomposition of aqueous ammonia in the absence and presence of oxygen using 184.9 nm UV light. 10 It was found that hydrazine was mainly produced by the dimerization of NH 2 radicals and oxygen affected the formation of hydrazine. In order for a photochemical reaction to occur, reactant chemical species must absorb the light illuminated. NH 3(aq) , NH 4 + (aq) , OH aq and H 2 O species exist in the aqueous ammonia solution. Since such chemical species have relatively strong intramolecular chemical force, a high enough energy is necessary to begin the photochemical reaction. It corresponds to vacuum UV light to break the chemical bond of such chemical species. The photochemical reaction of aqueous ammonia can not be carried out by a natural ultraviolet solar radiation on the earth's surface, because the solar energy reached on the earth's surface is the wavelength above λ = 314 nm UV light. It is necessary to use a photocatalyst to begin the photochemical decomposition of aqueous ammonia. Metal oxide such as titanium oxide and zinc oxide may be used for the purpose as a photocatalyst. It is well known that titanium oxide absorbs photons with energy higher than its bandgap (~3.2 eV) and electronhole pairs, so called geminated form, are produced.11 To our knowledge, there has been no report to date on the quantitative results for photochemical reaction of aqueous ammonia in the presence of TiO 2 particles. Since the photochemical reactions are very fast, products analysis is generally used to determine the photochemical behavior in a system. The aim of this study is to present the quantitative results for the photochemical reaction of the aqueous ammonia containing TiO 2 particles using 253.7 nm UV light, and to elucidate the behavior of TiO 2 during the photochemical reaction of aqueous ammonia based on the product analysis. Experimental SectionLightsource and Actinometry. Irradiations were carried out at 25 o C usinglow pressure Hg lamp (Osram HNS 10W/ U OFR). Low pressure Hg lamp is classified into two types depending on the method of its emitting wavelength; ozone generating lamp and ozonefree lamp. 12 The ozonefree lamp used in this study emits only 253.7 nm UV light, but on the other hand ozone generating lamp emits two monochromatic lights of 184.9 and 253.7 nm. The lamp was mounted in a quart...

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“…The disadvantage of this method is that very low irradiation intensities must be used, about one-thousandth of that produced by the polonium-210 source used in this work. This fact is significant because the ion yield •varies with intensity as shown by Burtt and his coworkers (17,19) and Luyckx (9). Burtt and his coworkers found that the ion yield increased slightly with increasing intensity.…”

Section: Rfp-1089mentioning

confidence: 96%

Radiolysis of Gaseous Ammonia.

Kazanjian¹,

Brown²

1968

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This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor.

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Alpha-Induced Decomposition of Ammonia. II. Effects of Variations in Intensity and Pressure

Cited by 12 publications

References 8 publications

The ?-radiolysis of water vapour in the presence of NH3 and O2

The ?-radiolysis of water vapour in the presence of NH3 and O2

Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂

Radiolysis of Gaseous Ammonia.

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Alpha-Induced Decomposition of Ammonia. II. Effects of Variations in Intensity and Pressure

Cited by 12 publications

References 8 publications

The ?-radiolysis of water vapour in the presence of NH3 and O2

The ?-radiolysis of water vapour in the presence of NH3 and O2

Photochemical Behavior of Ammonia in Aqueous Suspension of TiO2

Radiolysis of Gaseous Ammonia.

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Photochemical Behavior of Ammonia in Aqueous Suspension of TiO₂