Hydrogen production in the γγ-radiolysis of aqueous sulfuric acid solutions containing Al2O3, SiO2, TiO2 or ZrO2 fine particles

Yamada, R.

doi:10.1016/j.ijhydene.2007.11.028

Cited by 20 publications

(11 citation statements)

References 27 publications

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“…The second term was introduced to explain the additional production of H 2 due to the mordenite. The value of g MOR (H 2 ) was determined to be 2.3 6 10 78 mol/J, so that Equation (7) agrees with the experiment for w aq 4 0.2. The solid line in Figure 3(b) shows G total (H 2 ) calculated by Equation (7).…”

Section: Empirical Expression Of the H 2 Productionsupporting

confidence: 59%

“…Supposing the mordenite had no influence on the H 2 production, G aq (H 2 ) was expected to be the same as that for seawater in the absence of the mordenite and to be constant at 4.8 6 10 78 mol/J as shown by the dashed line in Figure 3(a). The additional production of H 2 suggests that the energy of g-rays originally absorbed by the mordenite was involved in the H 2 production, as proposed in the studies on the radiolysis of heterogeneous systems of aqueous solutions and solid oxides [4][5][6][7][8][9][10][11][12][13][14][15][16]. However, G aq (H 2 ) is inadequate for quantitative discussions on the additional production of H 2 because the absorbed energy of the mordenite is neglected in the calculation of G aq (H 2 ).…”

Section: Influence Of the Mordenitementioning

confidence: 99%

“…In these studies, the high productions of H 2 were interpreted as indicating that the energies originally absorbed by the zeolites transferred to the surfaces of the zeolites and decomposed the adsorbed water. In addition, the energy transfer process has been proposed as a possible mechanism of the H 2 production in a lot of studies on the influences of fine particles or porous materials of insoluble ceramics [7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen production in gamma radiolysis of the mixture of mordenite and seawater

Kumagai

Kimura

Taguchi

et al. 2013

Journal of Nuclear Science and Technology

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Hydrogen production by g-radiolysis of the mixture of mordenite, a zeolite mineral, and seawater was studied in order to provide basic points of view for the influences of zeolite minerals, of the salts in seawater, and of rise in temperature on the hydrogen production by the radiolysis of water. These influences are required to be considered in the evaluation of the hydrogen production from residual water in the waste zeolite adsorbents generated in Fukushima Dai-ichi Nuclear Power Station. As the influence of the mordenite, an additional production of hydrogen besides the hydrogen production by the radiolysis of water was observed. The additional hydrogen can be interpreted as the hydrogen production induced by the absorbed energy of the mordenite at the yield of 2.3610 78 mol/J. The influence of the salts was observed as increase of the hydrogen production. The influence of the salts can be attributed to the reactions of bromide and chloride ions inhibiting the reaction of hydrogen with hydroxyl radical. The influence of the rise in temperature was not significantly observed up to 608C in the mixture with seawater. The results show that the additional production of hydrogen due to the mordenite had little temperature dependence.

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Section: Empirical Expression Of the H 2 Productionsupporting

confidence: 59%

Section: Influence Of the Mordenitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrogen production in gamma radiolysis of the mixture of mordenite and seawater

Kumagai

Kimura

Taguchi

et al. 2013

Journal of Nuclear Science and Technology

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“…Besides, grains of U-Th-rich kenopyrochlores are often replaced/rimmed by pyrite ( Figure 3b) and valleriite ( Figure 3c) and sometimes by strontianite (Figure 3d), probably, due to radiolytic splitting of water into hydrogen peroxide and molecular hydrogen. In particular, with radiation dose growth, a water solution of H 2 SO 4 (below 200 • C) becomes significantly rich in H 2 due to H 2 O 2 [33,34], and this, probably, causes precipitation of sulfides around the radiation source. Table 3 shows the results of precision EPMA analyses conducted on 12 different members of the pyrochlore supergroup found in the Kovdor massif, and Table 4 presents statistical data on the PSM composition in different rocks of this massif.…”

Section: Occurrence and Morphologymentioning

confidence: 99%

Three-D Mineralogical Mapping of the Kovdor Phoscorite-Carbonatite Complex, NW Russia: III. Pyrochlore Supergroup Minerals

et al. 2018

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The pyrochlore supergroup minerals (PSM) are typical secondary phases that replace (with zirconolite-laachite) earlier Sc-Nb-rich baddeleyite under the influence of F-bearing hydrothermal solutions, and form individual well-shaped crystals in surrounding carbonatites. Like primary Sc-Nb-rich baddeleyite, the PSM are concentrated in the axial carbonate-rich zone of the phoscorite-carbonatite complex, so their content, grain size and chemical diversity increase from the pipe margins to axis. There are 12 members of the PSM in the phoscorite-carbonatite complex. Fluorine-and oxygen-dominant phases are spread in host silicate rocks and marginal carbonate-poor phoscorite, while hydroxide-dominant PSM occur mainly in the axial carbonate-rich zone of the ore-pipe. Ti-rich PSM (up to oxycalciobetafite) occur in host silicate rocks and calcite carbonatite veins, and Ta-rich phases (up to microlites) are spread in intermediate and axial magnetite-rich phoscorite. In marginal (apatite)-forsterite phoscorite, there are only Ca-dominant PSM, and the rest of the rocks include Ca-, Na-and vacancy-dominant phases. The crystal structures of oxycalciopyrochlore and hydroxynatropyrochlore were refined in the Fd3m space group with R 1 values of 0.032 and 0.054 respectively. The total difference in scattering parameters of B sites are in agreement with substitution scheme B Ti 4+ + Y OH − = B Nb 5+ + Y O 2−. The perspective process flow diagram for rare-metal "anomalous ore" processing includes sulfur-acidic cleaning of baddeleyite concentrate from PSM and zirconolite-laachite impurities followed by deep metal recovery from baddeleyite concentrate and Nb-Ta-Zr-U-Th-rich sulfatic product from its cleaning.

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“…As previously, an explanation could be that the presence of oxygen oxidized the structure of AmbOH resin, which generated less TMA and derivative compounds known to produce H 2g during their degradation (Ahmed et al, 1966;Traboulsi et al, 2012;Hall and Streat, 1963). Pure water γ-radiolysis is generally known to generate H 2g (Yamada et al, 2008(Yamada et al, , 2011 but in our case, in presence of the solid resin, water radiolysis took place in a different way because its precursors, H Á and e À solv , could react with the solid resin, decreasing their recombination probability, i.e. the H 2g production.…”

Section: Resins and Dosesmentioning

confidence: 91%

Experimental design approach for identification of the factors influencing the γ-radiolysis of ion exchange resins

Rébufa

Traboulsi

Labed

et al. 2015

Radiation Physics and Chemistry

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International audienceGamma radiolysis was investigated on a nuclear grade mixed bed ion exchange resin and its pure components under different irradiation conditions. Screening designs were performed to identify the factors influencing gas production after their γ-radiolysis and to compare their γ-degradation stability. Only hydrogen and trimethylamine quantities were considered as the response in the experimental designs. The other detected gases and water-soluble products were used to improve the resins degradation. Aerobic irradiation atmosphere decreased the H 2g production of AmbOH, MB400, and amines. The water presence increased the H 2g quantities for AmbH and decreased those for MB400 resin. Liquid water had no effect on H 2g production from AmbOH but was favorable to increased amine production. The H 2g production of AmbH increased with the absorbed dose that had little effect on the AmbOH resin. No impact of dose on the H 2g production was detected for MB400 that appeared to be less degraded

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Hydrogen production in the γγ-radiolysis of aqueous sulfuric acid solutions containing Al2O3, SiO2, TiO2 or ZrO2 fine particles

Cited by 20 publications

References 27 publications

Hydrogen production in gamma radiolysis of the mixture of mordenite and seawater

Hydrogen production in gamma radiolysis of the mixture of mordenite and seawater

Three-D Mineralogical Mapping of the Kovdor Phoscorite-Carbonatite Complex, NW Russia: III. Pyrochlore Supergroup Minerals

Experimental design approach for identification of the factors influencing the γ-radiolysis of ion exchange resins

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