Evaporation-Induced Reticular Growth of UiO-66_NH in Chitosan Films: Adsorption of Iodine.

Metal-organic frameworks (MOFs) combined with polymers as hybrid materials offer numerous advantages such as enhanced performances through synergistic effects at their interface. The primary challenge in developing polymer/MOF hybrid matrix films is ensuring optimal dispersion and strong adhesion of crystalline MOFs to the polymer without aggregation, weak interaction, or phase separation. In this study, hierarchically porous UiO-66_NH/chitosan (ZrCSx-) films were designed by crystallizing UiO-66_NH within a chitosan (CS) skeleton.

Probing the water adsorption and stability under steam flow of Zr-based metal-organic frameworks using Zr solid-state NMR spectroscopy.

The stability of metal-organic frameworks (MOFs) in the presence of water is crucial for a wide range of applications, including the production of freshwater, desiccation, humidity control, heat pumps/chillers and capture and separation of gases. In particular, their stability under steam flow is essential since most industrial streams contain water vapor. Nevertheless, to the best of our knowledge, the stability under steam flow of Zr-based MOFs, which are among the most widely studied MOFs, has not been investigated so far.

Virucidal activity of porphyrin-based metal-organic frameworks against highly pathogenic coronaviruses and hepatitis C virus.

The antiviral effect of four porphyrin-based Metal-Organic Frameworks (PMOFs) with Al and Zr, namely Al-TCPP, PCN-222, PCN-223 and PCN-224 was assessed for the first time against HCoV-229E, two highly pathogenic coronaviruses (SARS-CoV-2 and MERS-CoV) and hepatitis C virus (HCV). Infection tests were done under dark or light exposure for different contact times, and it was found that 15 min of light exposure were enough to give antiviral properties to the materials, therefore inactivating HCoV-229E by 99.98 % and 99.

Chemical shaping of CPO-27-M (M = Co, Ni) through an crystallization within chitosan hydrogels.

The preparation of MOF composites is considered as an effective method to address the challenges of shaping MOFs and to create porous solids with enhanced properties and broader applications. In this study, CPO-27-Co was crystallized a simple strategy within porous chitosan beads. The resulting CS@CPO-27-Co composites were tested for CO sorption and they demonstrated promising performances by exceeding 3 mmol g.

Stability of Iodine Species Trapped in Titanium-Based MOFs: MIL-125 and MIL-125_NH.

Two titanium-based MOFs MIL-125 and MIL-125_NH are synthesized and characterized using high-temperature powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), N sorption, Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), and electron paramagnetic resonance (EPR). Stable up to 300 °C, both compounds exhibited similar specific surface areas (SSA) values (1207 and 1099 m g for MIL-125 and MIL-125_NH, respectively). EPR signals of Ti are observed in both, whith MIL-125_NH also showing ─NH signatures.

Green synthesis of MOF-based textile composites for the degradation of a chemical warfare agent simulant.

A green synthesis of UiO-66-NH embedded in chitosan and deposited on textiles has been investigated for the degradation of chemical warfare agents. This method requires no heating or use of toxic solvents. The composite synthesized presents an interesting efficiency in detoxifying common simulants of chemical warfare agents, such as DMNP.

Probing oxygen exchange between UiO-66(Zr) MOF and water using O solid-state NMR.

The Zr-based Metal Organic Framework (MOF) UiO-66(Zr) is widely employed owing to its good thermal and chemical stabilities. Although the long-range structure of this MOF is preserved in the presence of water during several days, little is known about the formation of defects, which cannot be detected using diffraction techniques. We apply here O solid-state NMR spectroscopy at 18.

Enhanced Gas Adsorption in HKUST-1@Chitosan Aerogels, Cryogels, and Xerogels: An Evaluation Study.

This study investigates the use of chitosan hydrogel microspheres as a template for growing an extended network of MOF-type HKUST-1. Different drying methods (supercritical CO, freeze-drying, and vacuum drying) were used to generate three-dimensional polysaccharide nanofibrils embedding MOF nanoclusters. The resulting HKUST-1@Chitosan beads exhibit uniform and stable loadings of HKUST-1 and were used for the adsorption of CO, CH, Xe, and Kr.

Cooperative Synthesis of Raspberry-Like Covalent Organic Framework-Polymer Particles with a Radial Single-Crystal Grain Orientation.

Despite many efforts devoted toward the design of covalent organic frameworks (COFs) at the framework level by selecting the building blocks, their organization in the nano to meso regimes is often neglected. Moreover, the importance of processability for their applications has recently emerged and the synthesis of COF nanostructures without agglomeration is still a challenge. Herein, the first example of hybrid COF-polymer particles for which polymers are used to manipulate the 2D COF growth along a specific direction is reported.

Electron-Donor Functional Groups, Band Gap Tailoring, and Efficient Charge Separation: Three Keys To Improve the Gaseous Iodine Uptake in MOF Materials.

Metal-organic frameworks (MOFs) have been largely investigated worldwide for their use in the capture of radioactive iodine due to its potential release during nuclear accident events and reprocessing of nuclear fuel. The present work deals with the capture of gaseous I under a continuous flow and its subsequent transformation into I within the porous structures of three distinct, yet structurally related, terephthalate-based MOFs: MIL-125(Ti), MIL-125(Ti)_NH, and CAU-1(Al)_NH. The synthesized materials exhibited specific surface areas (SSAs) with similar order of magnitude: 1207, 1099, and 1110 m g for MIL-125(Ti), MIL-125(Ti)_NH, and CAU-1(Al)_NH, respectively.

Development of a TiO/Sepiolite Photocatalyst for the Degradation of a Persistent Organic Pollutant in Aqueous Solution.

A clay-based TiO nanocomposite material was synthesized by a facile method, to investigate its structure and photocatalytic efficiency. The supported TiO nanoparticles were generated using a sol-gel method, and subsequently, mixed with a suspension of sepiolite. The material was recovered in powder form (Mc-80) and then calcined to properly arrange the crystal lattice of the TiO particles for use in heterogeneous photocatalysis (Mc-80-500).

Capture and immobilization of gaseous ruthenium tetroxide RuO in the UiO-66-NH metal-organic framework.

Ru is a radioactive isotope usually generated by the nuclear industry within power plant reactors. During a nuclear accident, Ru reacts with oxygen, leading to the production of highly volatile ruthenium tetroxide RuO. The combination of volatility and radioactivity makes RuO, one of the most radiotoxic species and justifies the development of a specific setup for its capture and immobilization.

Crystalline Molecular Assemblies of Complexes Showing Eightfold Coordinated Niobium(IV) Dodecahedral Geometry in the Pyridine-Dicarboxylic Acid System.

The reactivity of 2,3-pyridine-dicarboxylic (known as quinolinic or qui) acid and 2,5-pyridine-dicarboxylic (known as isocinchomeronic or icc) acid has been investigated as a complexing agent toward the niobium(IV) tetrachloride precursor (NbCl·2THF) in different organic solvent mixtures. It resulted in the isolation of four crystalline assemblies of mononuclear coordination complexes [Nb(L)·solvent], where L is the monoprotonated quinolinate (Hqui) ligand (complexes -) or the monoprotonated isocinchomeronate ligand (complex ). For each complex, the discrete niobium(IV) center is eightfold coordinated to four oxygen atoms from the deprotonated carboxylate arm and four nitrogen atoms from the pyridine part of the dicarboxyl ligand with a dodecahedral environment [NbON].

Structural Variety of Niobium(V) Polyoxo Clusters Obtained from the Reaction with Aromatic Monocarboxylic Acids: Isolation of {Nb O}, {Nb O } and {Nb O } Cores.

The reactivity of aryl monocarboxylic acids (benzoic, 1- or 2-naphtoic, 4'-methylbiphenyl-4-carboxylic, and anthracene-9-carboxylic acids) as complexing agents for the ethoxide niobium(V) (Nb(OEt) precursor has been investigated. A total of eight coordination complexes were isolated with distinct niobium(V) nuclearities as well as carboxylate complexation states. The use of benzoic acid gives a tetranuclear core Nb (μ -O) (L) (OEt) ] (L=benzoate (1)) with four Nb-(μ -O)-Nb linkages in a square plane configuration.

Iodine Uptake by Zr-/Hf-Based UiO-66 Materials: The Influence of Metal Substitution on Iodine Evolution.

Many works reported the encapsulation of iodine in metal-organic frameworks as well as the I → I chemical conversion. This transformation has been examined by adsorbing gaseous iodine on a series of UiO-66 materials and the different Hf/Zr metal ratios (0-100% Hf) were evaluated during the evolution of I into I. The influence of the hafnium content on the UiO-66 structure was highlighted by PXRD, SEM images, and gas sorption tests.

Microwave-Assisted Synthesis of Porous Composites MOF-Textile for the Protection against Chemical and Nuclear Hazards.

Since the emergence of chemical, biological, radiological, and nuclear risks, significant efforts have been made to create efficient personal protection equipment. Recently, metal-organic framework (MOF) materials have emerged as new promising candidates for the capture and degradation of various threats, like chemical warfare agents (CWAs) or radioactive species. Herein, we report a new synthesis method of MOF-textile composites by microwave irradiation, with direct anchoring of MOFs on textiles.

Extrusion-Spheronization of UiO-66 and UiO-66_NH into Robust-Shaped Solids and Their Use for Gaseous Molecular Iodine, Xenon, and Krypton Adsorption.

The use of an extrusion-spheronization process was investigated to prepare robust and highly porous extrudates and granules starting from UiO-66 and UiO-66_NH metal-organic framework powders. As-produced materials were applied to the capture of gaseous iodine and the adsorption of xenon and krypton. In this study, biosourced chitosan and hydroxyethyl cellulose (HEC) are used as binders, added in low amounts (less than 5 wt % of the dried solids), as well as a colloidal silica as a co-binder when required.

Capture of Gaseous Iodine in Isoreticular Zirconium-Based UiO-n Metal-Organic Frameworks: Influence of Amino Functionalization, DFT Calculations, Raman and EPR Spectroscopic Investigation.

A series of Zr-based UiO-n MOF materials (n=66, 67, 68) have been studied for iodine capture. Gaseous iodine adsorption was collected kinetically from a home-made set-up allowing the continuous measurement of iodine content trapped within UiO-n compounds, with organic functionalities (-H, -CH , -Cl, -Br, -(OH) , -NO , -NH , (-NH ) , -CH NH ) by in-situ UV-Vis spectroscopy. This study emphasizes the role of the amino groups attached to the aromatic rings of the ligands connecting the {Zr O (OH) } brick.

Post-synthetic modification of aluminum trimesate and copper trimesate with TiO nanoparticles for photocatalytic applications.

Organic pollutants have been a significant source of concern in recent years due to their facile dissemination and harmful effects. In this work, two different metal-organic frameworks (MOFs) were initially prepared by hydrothermal treatment, namely aluminum trimesate (MIL-100(Al)) and copper trimesate (HKUST-1). These materials were subsequently submitted to a post-synthetic modification step to grow titania nanoparticles on their surface.

Stability and radioactive gaseous iodine-131 retention capacity of binderless UiO-66-NH granules under severe nuclear accidental conditions.

In the present work, we aim to investigate the ability of the zirconium-based MOF-type compound UiO-66-NH, to immobilize molecular gaseous iodine under conditions analogous to those encountered in an operating Filtered Containment Venting System (FCVS) line. Typically, the UiO-66-NH particles were exposed to I (beta and gamma emitters) and submitted to air/steam at 120 °C, under gamma irradiation (1.9 kGy h).

Quantitative Precipitation of Uranyl or Plutonyl Nitrate with N-(1-Adamantyl)acetamide in Nitric Acid Aqueous Solution.

The reactivity of the N-(1-adamantyl)acetamide ligand (L = ) has been evaluated as precipitating agent for the hexavalent uranyl cation ([U] = 20-60 g L) in concentrated nitric acid aqueous solution (0.5-5 M). It results in the formation of a crystalline complex (UO)()(NO)·2() (), in which the uranyl center is 8-fold coordinated to two chelating nitrate groups and two N-(1-adamantyl)acetamide (= ) ligands through the oxygen atom of the amide function.

Direct conversion of uranium dioxide UO to uranium tetrafluoride UF using the fluorinated ionic liquid [Bmim][PF].

The industrial fluorination of UO2 to UF4 is based on a complex process involving the manipulation of a large amount of HF, a very toxic and corrosive gas. We present here a safer way to accomplish this reaction utilizing ionic liquid [Bmim][PF6] as a unique reaction medium and fluoride source.

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process.

Modeling of plutonium(IV) behavior during an accidental fire in a reprocessing plant was considered using various non-radioactive metallic surrogates. Among those elements, cerium(IV) was supposed to be a suitable candidate due to possible formation of a complex with TPB, but its extractability and stability have not been studied previously under representative plutonium uranium reduction extraction (PUREX) conditions. In this work, we investigated the chemical analogy between cerium(IV) and plutonium(IV) in this extractive process and combustion thereof.

Time-controlled synthesis of the 3D coordination polymer U(1,2,3-Hbtc) followed by the formation of molecular poly-oxo cluster {U} containing hemimellitate uranium(iv).

Two coordination compounds bearing tetravalent uranium were synthesized in the presence of tritopic hemimellitic acid in acetonitrile with a controlled amount of water (HO/U ≈ 8) and structurally characterized. Compound 1, [U(1,2,3-Hbtc)]·0.5CHCN is constructed around an eight-fold coordinated uranium cationic unit [UO] linked by the poly-carboxylate ligands to form dimeric subunits, which are further connected to form infinite corrugated ribbons and a three-dimensional framework.