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The production of pure deuterium and the removal of tritium from nuclear waste are the key challenges in separation of light isotopes. Presently, the technological methods are extremely energy- and cost-intensive. Here we report the capture of heavy hydrogen isotopes from hydrogen gas by selective adsorption at Cu(I) sites in a metal-organic framework. At the strongly binding Cu(I) sites (32 kJ mol −1 ) nuclear quantum effects result in higher adsorption enthalpies of heavier isotopes. The capture mechanism takes place most efficiently at temperatures above 80 K, when an isotope exchange allows the preferential adsorption of heavy isotopologues from the gas phase. Large difference in adsorption enthalpy of 2.5 kJ mol −1 between D 2 and H 2 results in D 2 -over-H 2 selectivity of 11 at 100 K, to the best of our knowledge the largest value known to date. Combination of thermal desorption spectroscopy, Raman measurements, inelastic neutron scattering and first principles calculations for H 2 /D 2 mixtures allows the prediction of selectivities for tritium-containing isotopologues. Many applications require hydrogen isotopes and so it is important to develop alternative separation technologies. Here, the authors report a metal-organic framework capable of capturing deuterium from H 2 /D 2 mixtures, and go on to predict selectivity for isotopologues containing tritium.

The detection of deuterium and tritium retention in fusion devices via optical emission spectroscopy (OES) faces significant challenges due to experimental limitations, particularly in resolving hydrogen isotope Balmer alpha lines (H α , D α , and T α ). In this study, we propose and evaluate the coupling of laser ablation and laser-induced desorption with microwave-induced plasma (MIP) as an approach to resolve this problem. This approach effectively meets the resolution requirements for Balmer alpha lines, overcoming limitations of standard laser-induced breakdown spectroscopy (LIBS) setups. Optimization of Nd:YAG laser ablation was performed using pure copper and tungsten targets, while desorption, including femtosecond (fs) laser-induced desorption, was studied on graphite powder mixed with heavy water and water. The results demonstrate a significant improvement in spectral resolution and analytical performances, highlighting the potential of this technique for tritium retention studies in plasma-facing components.

A three-dimensional copper metal—organic framework with the rare chabazite (CHA) topology namely FJI-Y11 has been constructed with flexibly carboxylic ligand 5,5′-[(1,4-phenylenebis(methylene))bis(oxy)]diisophthalic acid (H 4 L). FJI-Y11 exhibits high water stability with the pH range from 2 to 12 at temperature as high as 373 K. Importantly, FJI-Y11 also shows high efficiency of hydrogen isotope separation using dynamic column breakthrough experiments under atmospheric pressure at 77 K. Attributed to its excellent structural stability, FJI-Y11 possesses good regenerated performance and maintains high separation efficiency after three cycles of breakthrough experiments.

Electrolysis of water is widely used for hydrogen isotope separation and the development of hydrogen evolution reaction (HER) catalysts with high selectivity and activity is of key importance. Herein, we propose single atom catalysts (SACs) as promising catalysts for efficient hydrogen isotope separation. Pt SACs and Pt nanoparticles (NPs) have been fabricated on nanoarray-structured nitrogen-doped graphite foil (NGF) substrate by a polyol reduction method. The as prepared Pt 1 /NGF electrode exhibits high activity and selectivity toward HER with a low overpotential of 0.022 V at 10 mA·cm −2 and a high separation factor of 6.83 for hydrogen and deuterium separation, much better than Pt NPs counterpart. Density functional theory (DFT) calculations ascribe the high activity and selectivity to the constructed Pt-N 2 C 2 structure. This work develops a new opportunity for the design and application of high-efficiency and stable SACs toward hydrogen isotope separation by electrolysis of water.

The unique adsorption performance of metal-organic frameworks (MOFs) indicates a new direction for gas separation and purification. The low-temperature distillation, as a traditional technique for hydrogen isotope separation, is limited as it is a high energy- and cost-intensive process. Instead of utilizing such a conventional separation route, we use ordered microporous frameworks based on a physical adsorption mechanism to solve the challenge of hydrogen isotope separation. Herein we analyze M-MOF-74 (M=Co, Ni, Mg, Zn), featuring a hexagonal channel about 11 Å and high density of open metal sites, for their ability to separate and purify deuterium from the hydrogen isotope mixture by dynamic column breakthrough experiments. Our results show that the combination of the strength of binding sites, density of coordinatively unsaturated metal sites and hydrogen isotope adsorption capacity of materials renders Co-MOF-74 as an optimal adsorbent for the capture of deuterium from hydrogen isotope mixtures in a simulated industrial process.

A database of surface Antarctic snow isotopic composition is constructed using available measurements, with an estimate of data quality and local variability. Although more than 1000 locations are documented, the spatial coverage remains uneven with a majority of sites located in specific areas of East Antarctica. The database is used to analyze the spatial variations in snow isotopic composition with respect to geographical characteristics (elevation, distance to the coast) and climatic features (temperature, accumulation) and with a focus on deuterium excess. The capacity of theoretical isotopic, regional, and general circulation atmospheric models (including “isotopic” models) to reproduce the observed features and assess the role of moisture advection in spatial deuterium excess fluctuations is analyzed.

Isotopic separation is of paramount importance for producing high-purity heavy hydrogen, yet the process remains hugely challenging. Here, we report on an Fe/ZSM-5 zeolite that was able to efficiently separate deuterium from protium via chemical quantum sieving. Structural data showed that four types of Fe species were present in Fe/ZSM-5 and oligomeric Fe–O clusters in the zeolite pores were correlated directly with gas selectivity. Gas adsorption revealed that Fe–O species served as the main adsorption sites and interacted with D 2 more strongly than with H 2 . D 2 /H 2 separation was exemplified using thermal desorption spectroscopy. D 2 /H 2 selectivity increased with Fe loading in Fe/ZSM-5 and a selectivity of 32.1 was obtained with an optimal loading of 7 wt%. The shift of desorption temperature supports the chemical affinity-based quantum sieving of D 2 over H 2 . This study demonstrates an effective strategy for enhancing D 2 /H 2 separation and the high selectivity means that Fe/ZSM-5 has strong potential in hydrogen isotope separation.

Instrumental data suggest that major shifts in tropical Pacific atmospheric dynamics and hydrology have occurred within the past century, potentially in response to anthropogenic warming. To better understand these trends, we use the hydrogen isotopic ratios of terrestrial higher plant leaf waxes ([delta]Dwax) in marine sediments from southwest Sulawesi, Indonesia, to compile a detailed reconstruction of central Indo-Pacific Warm Pool (IPWP) hydrologic variability spanning most of the last two millennia. Our paleodata are highly correlated with a monsoon reconstruction from Southeast Asia, indicating that intervals of strong East Asian summer monsoon (EASM) activity are associated with a weaker Indonesian monsoon (IM). Furthermore, the centennial-scale oscillations in our data follow known changes in Northern Hemisphere climate (e.g., the Little Ice Age and Medieval Warm Period) implying a dynamic link between Northern Hemisphere temperatures and IPWP hydrology. The inverse relationship between the EASM and IM suggests that migrations of the Intertropical Convergence Zone and associated changes in monsoon strength caused synoptic hydrologic shifts in the IPWP throughout most of the past two millennia.

Estimates suggest billions of dollars are lost annually in the US due to fuel tax fraud. One method of fuel fraud is called “cocktailing” and involves blending products that are non-taxed, lower value, taxed at a lower rate, or unwanted/less-refined petroleum to diesel fuels. The goal of this study was to investigate compound specific isotope analysis (CSIA) using isotope ratio mass spectrometry (IRMS) for small aromatics contained in diesel fuel to determine whether this approach could be used to identify cocktailing and potentially fingerprint possible sources. However, the high chemical complexity of diesel fuels complicates CSIA owing to the need to fully separate individual compounds for effective isotope analysis. Therefore, different methods were investigated to selectively isolate aromatics for CSIA and evaluate these methods for isotopic fractionation. Analyses indicate that there is enough variability in isotopic ratios (δ2H and δ13C) between toluene samples obtained from different sources to use CSIA to differentiate/identify the origin of potential fuel adulterants. Three isolation methods were identified that provided sufficiently pure aromatic fractions for CSIA: selective solvent extraction, ionic liquid coated solid phase microextraction (SPME), and a combination of the two. However, due to the labor-intensive nature of selective solvent extraction, ionic liquid coated SPME represents the best method to quickly isolate aromatics from diesel fuel, without sacrificing selectivity or sensitivity. All methods tested can result in isotopic fractionation, but this can be compensated for by applying a correction factor. Furthermore, the chemical composition of a sample appeared to be important in the degree to which fractionation occurred during isolation. While the tested approaches for aromatic extraction from diesel showed promise, additional studies are required to refine and validate the methods prior to routine use in fuel cocktailing investigations. [Display omitted] •Toluene from diverse sources has adequate δ2H and δ13C variability for isotopic differentiation from other chemicals in a fuel.•Four different isolation methods coupled with CSIA of small aromatics in diesel fuel were evaluated.•Three isolation methods provided sufficiently pure aromatic fractions for CSIA, ionic liquid coated SPME was the best.•All isolation methods resulted in some isotopic fractionation; however, this is amenable to mathematical correction

The separation of mixtures of hydrogen isotopes is one of the greatest challenges of modern separation technology. A newly proposed separation mechanism, the quantum sieving (QS) effect, is expected to achieve high separation factors, the main desired properties for hydrogen isotope separation (HIS). Metal–organic frameworks (MOFs) and zeolites are excellent candidates to study these quantum effects because of their well-defined and tunable pore structure and the potential to introduce strong adsorption sites directly into the framework structure. This paper briefly discusses the fundamentals of QS of hydrogen isotopes in nanoporous materials, mainly including kinetic quantum sieving (KQS) and chemical affinity quantum sieving (CAQS). Recent experimental advances in the separation of hydrogen isotopes from MOFs and zeolites are highlighted.