Metal–organic frameworks (MOFs) are promising candidates for the catalytic hydrolysis of nerve agents and their simulants. Though highly efficient, bulk water and volatile bases are often required ...for hydrolysis with these MOF catalysts, preventing real-world implementation. Herein we report a generalizable and scalable approach for integrating MOFs and non-volatile polymeric bases onto textile fibers for nerve agent hydrolysis. Notably, the composite material showed similar reactivity under ambient conditions compared to the powder material in aqueous alkaline solution. This represents a critical step toward a unified strategy for nerve agent hydrolysis in practical settings, which can significantly reduce the dimensions of filters and increase the efficiency of protective suits.
Here we discuss the removal of nitrogen dioxide, an important toxic industrial chemical and pollutant, from air using the MOF UiO‐66‐NH2. The amine group is found to substantially aid in the removal, ...resulting in unprecedented removal capacities upwards of 1.4 g of NO2 /g of MOF. Furthermore, whereas NO2 typically generates substantial quantities of NO on sorbents, the amount generated by UiO‐66‐NH2 is significantly reduced. Of particular significance is the formation of a diazonium ion on the aromatic ring of the MOF, and the potential reduction of NO2 to molecular nitrogen.
Clean air with MOF: The metal–organic framework UiO‐66‐NH2 was used to remove toxic nitrogen dioxide from streams of air with only small amounts of nitric oxide formed. The highly efficient reaction was due to formation of several nitrate species, as well as a diazonium ion on the MOF secondary building unit. It is also possible that molecular nitrogen was formed during the reaction.
Evaluation of UiO-66 and UiO-67 metal–organic framework derivatives as catalysts for the degradation of soman, a chemical warfare agent, showed the importance of both the linker size and ...functionality. The best catalysts yielded half-lives of less than 1 min. Further testing with a nerve agent simulant established that different rate-assessment techniques yield similar values for degradation half-lives.
This work investigates the processing–structure–activity relationships that ultimately facilitate the enhanced performance of UiO-66-NH2 metal–organic frameworks (MOFs) in electrospun polystyrene ...(PS) fibers for chemical warfare agent detoxification. Key electrospinning processing parameters including solvent type (dimethylformamide DMF) vs DMF/tetrahydrofuran THF), PS weight fraction in solution, and MOF weight fraction relative to PS were varied to optimize MOF incorporation into the fibers and ultimately improve composite performance. It was found that composites spun from pure DMF generally resulted in MOF crystal deposition on the surface of the fibers, while composites spun from DMF/THF typically led to MOF crystal deposition within the fibers. For cases in which the MOF was incorporated on the periphery of the fibers, the composites generally demonstrated better gas uptake (e.g., nitrogen, chlorine) because of enhanced access to the MOF pores. Additionally, increasing both the polymer and MOF weight percentages in the electrospun solutions resulted in larger diameter fibers, with polymer concentration having a more pronounced effect on fiber size; however, these larger fibers were generally less efficient at gas separations. Overall, exploring the electrospinning parameter space resulted in composites that outperformed previously reported materials for the detoxification of the chemical warfare agent, soman. The data and strategies herein thus provide guiding principles applicable to the design of future systems for protection and separations as well as a wide range of environmental remediation applications.
Metal organic frameworks (MOFs) are a leading class of porous materials for a wide variety of applications, but many of them have been shown to be unstable toward water. Cu-BTC (1,3,5 ...benzenetricarboxylic acid, BTC) was treated with a plasma-enhanced chemical vapor deposition (PECVD) of perfluorohexane creating a hydrophobic form of Cu-BTC. It was found that the treated Cu-BTC could withstand high humidity and even submersion in water much better than unperturbed Cu-BTC. Through Monte Carlo simulations it was found that perfluorohexane sites itself in such a way within Cu-BTC as to prevent the formation of water clusters, hence preventing the decomposition of Cu-BTC by water. This PECVD of perfluorohexane could be exploited to widen the scope of practical applications of Cu-BTC and other MOFs.
Metal-organic frameworks (MOFs) in their free powder form have exhibited superior capacities for many gases when compared to other materials, due to their tailorable functionality and high surface ...areas. Specifically, the MOF HKUST-1 binds small Lewis bases, such as ammonia, with its coordinatively unsaturated copper sites. We describe here the use of HKUST-1 in mixed-matrix membranes (MMMs) prepared from polyvinylidene difluoride (PVDF) for the removal of ammonia gas. These MMMs exhibit ammonia capacities similar to their hypothetical capacities based on the weight percent of HKUST-1 in each MMM. HKUST-1 in its powder form is unstable toward humid conditions; however, upon exposure to humid environments for prolonged periods of time, the HKUST-1 MMMs exhibit outstanding structural stability, and maintain their ammonia capacity. Overall, this study has achieved all of the critical and combined elements for real-world applications of MOFs: high MOF loadings, fully accessible MOF surfaces, enhanced MOF stabilization, recyclability, mechanical stability, and processability. This study is a critical step in advancing MOFs to a stable, usable, and enabling technology.
Zirconium-based metal–organic frameworks (Zr-MOFs) based on edge-transitive nets such as fcu, spn, she, csq, and ftw with diverse potential applications have been widely reported. Zr-MOFs based on ...the highly connected 6,12-connected alb net, however, remain absent on account of synthetic challenges. Herein we report the ligand-directed reticular syntheses and isoreticular expansion of a series of Zr-MOFs with the edge-transitive alb net from 12-connected hexagonal-prismatic Zr6 nodes and 6-connected trigonal-prismatic linkers, i.e., microporous NU-1600, mesoporous NU-1601, and mesoporous NU-1602. These Zr-MOFs exhibit remarkable activities toward the destruction of a nerve agent (soman) and a nerve agent simulant (DMNP).
Fibrous composite materials provide distinct advantages in large surface area and enhanced molecular transport through the media, lending themselves to diverse applications. Despite substantial ...development in synthetic methods, it is still lacking in insights into structure–property relationships that can correlate features of the functional materials to absorptive, transport, and catalytic performance of the composites. Herein, for the first time, a systematic structure–property–function analysis is provided for Zr‐based metal–organic frameworks (MOFs) coated onto polypropylene nonwoven textiles. MOF fraction on the fabric and defect density in MOF microstructures are controlled by an in situ seeded growth, where fiber surfaces are pretreated with metal‐oxide by atomic layer deposition. The best performing MOF‐fiber composite shows a rapid catalytic hydrolysis rate for a chemical warfare agent simulant, p‐nitrophenyl phosphate with t1/2 < 5 min, and a significant permeation restriction of a real agent GD‐vapor through the composite. Of added advantage is the observed moisture vapor transport rate of 15 000 g m−2 day−1 for the composite, which is notably superior to that of other commercially available chemical‐protective fabrics. The chemical‐protective composites realized in this work overcome the breathability/detoxification trade‐off and show promise for the materials to be deployed in a realistic field.
High‐performing MOF‐textile catalysts are obtained by a combination of seed‐mediated and modulator‐induced synthetic approaches, showing a substantial enhancement in hydrolytic‐ and adsorptive removal of hazardous chemicals. In addition, the composites reported here also feature an excellent moisture vapor transport rate, overcoming breathability/detoxification trade‐off and ensuring their practical use as a field‐deployable chemical‐protective system.
The nerve agent VX is among the most toxic chemicals known to mankind, and robust solutions are needed to rapidly and selectively deactivate it. Herein, we demonstrate that three Zr6-based ...metal–organic frameworks (MOFs), namely, UiO-67, UiO-67-NH2, and UiO-67-N(Me)2, are selective and highly active catalysts for the hydrolysis of VX. Utilizing UiO-67, UiO-67-NH2, and UiO-67-N(Me)2 in a pH 10 buffered solution of N-ethylmorpholine, selective hydrolysis of the P–S bond in VX was observed. In addition, UiO-67-N(Me)2 was found to catalyze VX hydrolysis with an initial half-life of 1.8 min. This half-life is nearly 3 orders of magnitude shorter than that of the only other MOF tested to date for hydrolysis of VX and rivals the activity of the best nonenzymatic materials. Hydrolysis utilizing Zr-based MOFs is also selective and facile in the absence of pH 10 buffer (just water) and for the destruction of the toxic byproduct EA-2192.
Abstract
Conserving more than 7 million plant germplasm accessions in 1,750 genebanks worldwide raises the hope of securing the food supply for humanity for future generations. However, there is a ...genetic cost for such long-term germplasm conservation, which has been largely unaccounted for before. We investigated the extent and variation of deleterious and adaptive mutations in 490 individual plants representing barley, wheat, oat, soybean, maize, rapa, and sunflower collections in a seed genebank using RNA-Seq technology. These collections were found to have a range of deleterious mutations detected from 125 (maize) to 83,695 (oat) with a mean of 13,537 and of the averaged sample-wise mutation burden per deleterious locus from 0.069 to 0.357 with a mean of 0.200. Soybean and sunflower collections showed that accessions acquired earlier had increased mutation burdens. The germplasm with more years of storage in several collections carried more deleterious and fewer adaptive mutations. The samples with more cycles of germplasm regeneration revealed fewer deleterious and more adaptive mutations. These findings are significant for understanding mutational dynamics and genetic cost in conserved germplasm and have implications for long-term germplasm management and conservation.
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