JOURNAL OF NUCLEAR MATERIALS
·
2023
·
IF 3.1
S. Krat,A. Prishvitsyn,Yu. Gasparyan
A probabilistic and diffusion-based model describing concentrations of multiple hydrogen isotopes simultaneously co-depositing with slowly grown metal layer is given. The conditions modeled are identical to stationary ion implantation into bulk material with infinite fluence. Ratios of different multiple hydrogen isotopes occupying same trapping sites in metal layers co-deposited from plasma are estimated. It is shown that if hydrogen isotopes have different detrapping energies in regards to the same trap (vacancy, dislocation, etc.), only the concentration of the isotope with highest detrapping energy decreases monotonously with deposition temperature. The uncertainty of tritium concentration in co-deposited layer based on the uncertainty in detrapping energy of tritium and deuterium is evaluated; for an 0.01 eV difference, a >10% tritium concentration uncertainty is predicted.
研究领域:
材料科学
·
核能工程
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DOI
高影响因子
ORGANIC GEOCHEMISTRY
·
2024
·
IF 2.6
Wenna Liu,Wanglu Jia,Qiang Wang,Jian Chen,Jinbu Li,Ping’an Peng
The isotopic fractionation of organic compounds during evaporation is one of the most critical issues in the field of stable isotopes. The hydrogen (H) isotopic compositions of light hydrocarbons (LHs) in oil have gained increasing interest in the research of oil genesis in recent years. However, compared to carbon (C) isotopes, our understanding of H isotopic fractionation patterns and influences for various types of LHs during evaporation is limited. In this study, we performed evaporation experiments at a constant temperature on LHs in three systems: single compound, alkane mixture, and light oil. We assessed the contents and H isotopic compositions of individual LHs in the residual liquid phase. The degree of H isotopic fractionation and influencing factors are studied combined with C isotopes. The H isotopic fractionation of LHs exhibits “inverse isotope fractionation” characteristics (a depletion in D in the residual LHs) with progressive evaporation, which is opposite to the C isotopic fractionation. The degree of isotopic fractionation is influenced by the evaporation system, the compounds’ molecular weight, and their structure. (1) The isotopic fractionation degree of H and C decreases in the following order: light oil > alkane mixture > single compound system. This difference may be related to the unsaturation level of the evaporative system and the evaporation matrix. (2) For LHs with the similar structure in the same evaporation system, the degree of H isotopic fractionation increases with increasing molecular weight due to the buffering effect of the sample pool, while the magnitude of C isotopic fractionation decreases. (3) For LHs with the same C number, methylcyclohexane (MCH) has a lower evaporation rate and less isotopic fractionation than the other C 7 compounds like 3-methylhexane (3-MH), n -heptane ( n C 7 ), and toluene (Tol). The distinctive fractionation characteristics of H isotopes make them very useful in geological applications. Combining H and C isotopic compositions of the same compound with the commonly used molecular ratios of LHs (e.g., n C 7 /MCH, Tol/ n C 7 ) enables full differentiation of three critical processes controlling oil formation: evaporation, thermal maturation, and biodegradation. Furthermore, the differences in H isotopic compositions between C 7 LHs (3-MH, n C 7 , and Tol) may be changed by evaporation, but the variation range is much smaller than that caused by source differences. Therefore, combining H and C isotopes may have great potential for oil source characterizations.
研究领域:
地球化学
·
石油地质学
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产品关联
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Jinfeng Zheng,Jianbo Tang,Shenhao Jin,Hao Hu,Zhi-Jiang Jiang,Jia Chen,Jian-Fei Bai,Zhanghua Gao
An efficient method has been developed for the synthesis of α-deuterated α-amino esters via hydrogen isotope exchange of α-amino esters in D2O with 2-hydroxynicotinaldehyde as a catalyst under mild conditions. This methodology exhibits a wide range of substrate scopes, remarkable functional group tolerance, and affording the desired products in good yields with excellent deuterium incorporation. Notably, the ortho-hydroxyl group and the pyridine ring of the catalyst play a crucial role in the catalytic activity, which not only stabilizes the carbon-anion intermediates but also enhances the acidity of the amino esters’ α–C–H bond.
研究领域:
有机化学
·
合成化学
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DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Ming Wen,Min Chen,Guang-Kun Ren,Pei-Long Li,Chao Lv,Yong Yao,Yin-Ke Liu,Sun-Jie Deng,Zhe Zheng,Ci-Gang Xu,De-Li Luo
Isotopes of hydrogen are playing an increasingly important role in applications such as controllable nuclear fusion and other nuclear processes, yet directly separating isotopic water from its mixture is still energy-intensive and largely limited by the moderate separation factor values. In this study, Graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets , combining optimized hydrophobicity by grafting perfluoroalkylsilanes (PFAS), have been used for improving the selectivity of isotopic water in membrane distillation. By utilizing heavy/light water mixture as a model, permeation flux and isotopic selectivity of the membranes are systematically evaluated. The graphene oxide membranes, particularly for the rGO grafted by PFAS, exhibit enhanced selectivity with an increased isotopic separation factor, as compared with that of commercial membranes, which is probably due to the efficient synergy between unimpeded nanochannels and near-super hydrophobic surface. A maximum mean separation factor value of 1.067, combined with a permeation flux of 0.47 kg m −2 h −1 have been achieved for the grafted rGO -membrane reduced at 750 °C. Furthermore, our study demonstrates utilizing two-dimensional materials, like GO and rGO, can be an effective avenue for promoting the isotopic selectivity in membrane distillation, based on increasing hydrophobic water vapor channels with higher selectivity.
研究领域:
材料科学
·
环境工程
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产品关联
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2017
·Vol. 20
·期 2
·1700745
·
IF 2.319
Nan Sun,Quan-Ping Zhang,Hao-Ran Sun,Wen-Bin Yang,Yuan-Lin Zhou,Jiang-Feng Song,De-Li Luo
5A molecular sieves have been widely used as adsorbents in cryogenic distillation for hydrogen isotope separation in fusion reactor engineering, but its low thermal conductivity is detrimental to the process stability. Improving the thermal conductivity of 5A molecular sieves is one of the most important goals for high-performance devices. Here, firm segregated structures with boron nitride sheets (BNs) are constructed around 5A molecular sieve particles. SEM results show 30 µm BNs tend to form the better networks in comparison with that of 0.12 µm BNs at 40 wt% loadings. It is further verified that BNs with the larger size promote the thermal conductivity. Meanwhile, the thermal conductivity increases with the increasing amounts of BNs. XRD and specific surface area results indicate that the sintering and the addition of BNs exert negligible effects on the structure of 5A molecular sieve. These results indirectly show 5A molecular sieve with BNs segregated structures is very likely to be used for the application of hydrogen isotopic separation. Besides, this work provides new insight into the construction of segregated structure in inorganic porous materials.
研究领域:
材料科学
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核工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Xiaoxiao Chen,Mengyao Liu,Lijuan Zhang,Yunshan Zhou,Enming Ping,Chunyan Ding
ZIF-67@NH 2 –SiO 2 composites were prepared by loading the metal-organic frameworks ZIF-67 on amino modified SiO 2 gel particles (NH 2 –SiO 2 , 80–100 mesh) through layer-by-layer self-assembly method. Systematic investigation on the effects of ZIF-67 loading amounts on NH 2 –SiO 2 packed stainless steel chromatographic column (specification 1.0 m×2.0 mm I.D.), the flow rate of He as carrier gas and the injection amount of mixed gas (H 2 /D 2 ) on the hydrogen isotope H 2 /D 2 separation performance at liquid nitrogen temperature, unraveled the optimal conditions for H 2 /D 2 isotope separation . The results showed that the optimal stationary phase materials under the optimized conditions can effectively separate H 2 and D 2 with separation resolution R = 1.52 and the separation time t = 10.15 min. The superior performance of the ZIF-67 is tentatively thought to be due to kinetic quantum sieving (pore size 3.3 Å) effect and chemical affinity sieving effect of Co ion in ZIF-67.
研究领域:
分析化学
·
材料科学
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产品关联
DOI
高影响因子
ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY
·
2016
·Vol. 23
·期 1
·13-18
·
IF 1.87
Wang Weiwei,Ren Xingbi,Yu Mingming,Xia Lidong,Liu Ning,Peng Shuming
By a solution impregnation method, three modified stationary phases were prepared by contacting activated alumina with MnCl 2 at different MnCl 2 :Al 2 O 3 molar ratios = 1:10, 1:5, 1:2.5, respectively. N 2 sorption isotherms at 78 K were examined for the unmodified and modified samples, from which pore size distributions (PSD) of textural properties were derived with density function theory. Elution chromatographic tests of hydrogen isotopes were carried out at 78 K. The results indicated that both the microporous specific surface area (SSA) and the mesoporous SSA decline after modification, while the microporous SSA remains nearly unvaried among the modified ones. The chromatographic retention times as well as the bandwidths decline as the Mn content rises. The resolution of chromatographic peaks increases after modification, it remains unvaried and then decreases as the Mn content increases. The PSD of alumina SSA changed by the modification significantly influences the hydrogen isotopic elution chromatography.
研究领域:
材料科学
·
核化学
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产品关联
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2021
·
IF 4.354
Junhua Kong,Zhi-Jiang Jiang,Jiayuan Xu,Yan Li,Hong Cao,Yanan Ding,Bencan Tang,Jia Chen,Zhanghua Gao
A practical and scalable ortho-selective deuteration of aromatic aldehydes was accomplished by Pd-catalyzed hydrogen isotope exchange with deuterium oxide as an inexpensive deuterium source. The use of tert-leucine as a transient directing group facilitates the exchange, affording a wide range of ortho-deuterated aromatic aldehydes with deuterium incorporation up to 97%. The control experiments suggest that the addition of silver trifluoroacetate resists the unexpected reduction of Pd(II), while the theoretical study indicates a rapid reversible concerted metalation–deprotonation process.
研究领域:
有机化学
·
同位素化学
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产品关联
DOI
PubMed
高影响因子
CATALYSIS COMMUNICATIONS
·
2023
·
IF 3.7
Zengqi Lu,Xiaolong Fu,Jingwei Hou,Lei Yue,Jiamao Li,Guangming Ran,Chengjian Xiao,Xiaolin Wang
In order to enhance hydrogen-water isotope exchange performance, a hydrophobic microenvironment was constructed within the catalyst support and a bimetal catalyst was loaded. The catalyst was superhydrophobic, resulting in a significant improvement in performance. Through the adsorption/desorption performance test of water vapor, it was observed that the hydrophobic microenvironment could increase the diffusion rate of the reactant, while metal doping modification could enhance the concentration of the reactant around the active center. Comparatively, the catalytic performance of the catalyst containing the hydrophobic microenvironment was superior to that of the normal hydrophobic catalysts, even when the hydrophobicity was slightly diminished.
研究领域:
化学
·
材料科学
·
核能科学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2024
·
IF 13
Guilin Wei,Linsen Zhou,Xianglin Wang,Ru Tang,Kelin Chen,Junhong Luo,Jiangfeng Song,Yan Shi,Ning Liu,Xingwen Feng
The construction, use, and maintenance of tritium-related equipment will inevitably produce tritium-containing radioactive waste gas, and the production of efficient catalysts for tritium removal remains a difficult problem. Herein, silicalite-1 zeolite with entrapped Pt nanoclusters is skillfully post-oxidized at an appropriate temperature, building highly active Pt─O sites on the nanoclusters to achieve efficient oxidation of hydrogen isotopes at low temperatures. The designed Pt─O sites can directly participate in the oxidation reaction of hydrogen isotopes. Compared to the case without Pt─O sites, the presence of these sites significantly reduces the reaction energy barrier to 0.55 eV, enabling the catalyst to achieve a hydrogen conversion rate of 99% at a low temperature of 40 °C. Specifically, the O atoms consumed by the Pt─O sites in the reaction are replaced by O 2 gas and this cycle repeats, which is consistent with the Mars-van Krevelen (M–K) theory. This ensures efficient catalytic oxidation of hydrogen isotopes, and provides an astonishingly high conversion rate of 99% in the nearly 34 days restart performance test. The results of this study provide insights into the strategic design of efficient catalysts for hydrogen isotope oxidation.
研究领域:
催化化学
·
核能科学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
Water
·
2024
·Vol. 16
·期 7
·967
·
IF 3
Zhen Luo,Yong Hu,Linyuan Cao,Shen Li,Xin Liu,Ruizhi Fan
The treatment of tritiated nuclear wastewater is facing greater challenges with the continuous expansion of the nuclear industry. The key to solving the issue of detritium in low-abundance tritium water lies in developing highly efficient and cost-effective hydrogen isotope separation technology. Graphene oxide (GO) membrane separation method exhibits greater potential compared to other existing energy-intensive technologies for the challenging task of hydrogen isotope separation in nuclear wastewater. In recent years, researchers have explored few strategies to enhance the performance of graphene oxide (GO) membranes in hydrogen isotope water treatment, recognizing the current limitations in separation efficiency. In this study, the GO/g-C3N4composite membrane has been successfully employed for the first time in the separation of hydrogen isotopes in water. A series of GO membranes were prepared and their performances were tested by a self-made experimental device. As a result, the separation performance of the GO membrane was enhanced by the modification with graphitic carbon nitride (g-C3N4). The permeation rate of the GO/g-C3N4membrane was higher than that of the GO membrane, while maintaining a high separation factor. Our study also demonstrated that this phenomenon can be attributed to the changes in membrane structure at the microscopic scale. The H/D separation factor and the permeate flux of the composite membrane containing g-C3N4of 6.7% by mass were 1.10 and 7.2 × 10−5g·min−1·cm−2are both higher than that of the GO membrane under the same experimental conditions, which is promising for the isotope treatment.
研究领域:
材料科学
·
环境科学
·
核能工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Xiaoyu Hu,Fengyun Ding,Renjin Xiong,Yongtao An,Xingwen Feng,Jiangfeng Song,Linsen Zhou,Peilong Li,Changlun Chen
Realizing ideal deuterium separation from isotopic mixtures remains a daunting challenge because of their almost identical sizes, shapes, and physicochemical properties. Using the quantum sieving effect in porous materials with suitable pore size and open metal sites (OMSs) enables efficient hydrogen isotope separation. Herein, synthetic HKUST-1-derived microporous mixed-valence Cu(I)Cu(II)-BTC (BTC = benzene-1,3,5-tricarboxylate), featuring a unique network of distinct Cu(I) and Cu(II) coordination sites, can remarkably boost the D2/H2 isotope separation, which has a high selectivity (SD2/H2) of 37.9 at 30 K, in comparison with HKUST-1 and other porous materials. Density functional theory (DFT) calculations indicate that the introduction of Cu(I) macrocycles in the framework decreases the pore size and further leads to relatively enhanced interaction of H2/D2 molecules on Cu(II) sites. The significantly enhanced selectivity of Cu(I)Cu(II)-BTC at 30 K can be mainly attributed to the synergistic effect of kinetic quantum sieving (KQS) and chemical affinity quantum sieving (CAQS). The results reveal that Cu(I) OMSs exhibit counterintuitive behaviors and play a crucial role in tuning quantum sieving without a complex structural design, which provides a deeper insight into quantum sieving mechanisms and a new strategy for the intelligent design of highly efficient isotope systems.
研究领域:
材料科学
·
物理化学
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产品关联
DOI
PubMed
高影响因子
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