CO2 Adsorption/Desorption in FAU Zeolite Nanocrystals: In Situ Synchrotron X-ray Powder Diffraction and in Situ Fourier Transform Infrared Spectroscopic Study

International audienceThe host–guest and guest–guest interactions governing the CO2 adsorption/desorption in two nanosized zeolite samples with FAU framework type and different Si/Al ratios (Na–X Si/Al = 1.24 and Na–Y Si/Al = 2.54) and cation distribution were investigated by in situ synchrotron high-resolution X-ray powder diffraction (XRPD) and in situ Fourier transform infrared (FTIR) spectroscopy. The two complementary techniques allow probing the CO2 adsorption/desorption in the FAU zeolites at different levels, that is, average structure by XRPD versus local structure by FTIR spectroscopy . The presence of physisorbed CO2 molecules in both zeolites was detected by XRPD, whereas only a high amount of chemisorbed CO2 in the Na–X zeolite was found. The presence of unshielded Na cations and H2O molecules in the supercage of the Na–X sample induces the formation of stable bidentate bicarbonate groups. Evacuating CO2-loaded samples resulted in the efficient removal of physisorbed CO2 from both nanosized zeolites; on the contrary, high temperature is required to remove the chemisorbed species from the nanosized Na–X zeolite. Understanding the CO2 sorption behavior and capacity of nanosized zeolites is of great importance in broadening their use in environmental, clinical, and biomedical applications

Sample preparation for an optimized extraction of localized metabolites in lichens: Application to Pseudevernia furfuracea

International audienceLichens are symbiotic organisms known for producing unique secondary metabolites with attractive cosmetic and pharmacological properties. In this paper, we investigated three standard methods of preparation of Pseudevernia furfuracea (blender grinding, ball milling, pestle and mortar). The materials obtained were characterized by electronic microscopy, nitrogen adsorption and compared from the point of view of extraction. Their microscopic structure is related to extraction efficiency. In addition, it is shown using thalline reactions and mass spectrometry mapping (TOF-SIMS) that these metabolites are not evenly distributed throughout the organism. Particularly, atranorin (a secondary metabolite of interest) is mainly present in the cortex of Pseudevernia furfuracea. Finally, using microwave assisted extraction (MAE) we obtained evidence that an appropriate preparation can increase the extraction efficiency of atranorin by a factor of fiv

Extraction of metabolites of lichen "Pseudevernia furfuracea" via ionic liquids technology under microwave irradiation

Les lichens sont des organismes symbiotiques constitués d'un champignon (mycobionte) associé à une algue et/ou une cyanobactérie (photobionte). Leurs métabolites secondaires sont des molécules originales appartenant au groupe des depsides, depsidones, dibenzofuranes et présentent un intérêt pour la cosmétique et/ou la pharmaceutique en raison de leur propriété antibiotique, anti-inflammatoire, antioxydant, filtre UV. Nous avons choisi d'étudier le lichen Pseudevenia furfuracea qui est l'un des lichens utilisés en tant que matière première pour la parfumerie et la cosmétique (1900 tonnes / an), car il est d'une part abondant dans la nature et d'autre part, il possède des métabolites secondaires très variés. Classiquement, les extraits utilisés sont obtenus par extraction au reflux de solvants organiques; cette méthode à l'inconvénient d'induire des durées d'extractions relativement longues et est consommatrice en solvants. L'objectif de notre travail est d'extraire les métabolites secondaires d'une manière sélective et innovante tout en diminuant la durée d'extraction. Pour cela, nos travaux reposent sur l'extraction assistée sous micro-onde (EAM) combinée ou non aux liquides ioniques. Dans ce dessein, deux familles de liquides ioniques (LIs) "hydrophiles" et "hydrophobes" ayant un cation imidazolium et pyridinium ont été synthétisés. Trois différentes préparations de lichen (mixé, broyé au mortier et broyé planétaire) ont été effectuées en faisant varier la granulométrie et chaque préparation a été étudiée par microscopie électronique à balayage. L'optimisation de l'EAM a été effectuée à une température d'extraction optimale de 75 °C et a permis de générer un énorme gain de temps (24 h sous conditions classiques contre 15 min sous irradiation micro-onde). Une étude comparative des taux d'extraction entre l'EAM et l'extraction en condition classique a été éffectuée par analyse au spectrodensitomètre CAMAG®, celle-ci a montré que la première est plus performante dans la plupart des cas. L'utilisation des liquides ioniques a mis en évidence l'existence d'une sélectivité d'extraction en fonction de la structure des LIs qui résulte d'interactions intermoléculaires entre les LIs et les substances extraites. L'effet de chaque liquide ionique sur la dégradation d'un des métabolites, en particulier l'atranorine, a également été étudié. Également, les interactions entre un liquide ionique et la surface du lichen ont été étudiées par mesure d'angle de contact et par les mesures de Brunauer Emett et Teller. Une extraction à plus grande échelle a été réalisée pour étudier la reproductibilité de la méthode et la possibilité de recycler le liquide ionique.Lichens are symbiotic organisms constituted of fungus (mycobiont) associated to algae and/or cyanobacteria (photobiont). Their secondary metabolites are original molecules belonging to the group of depsides, depsidones, dibenzofurans. Lichens presented special interest for cosmetic and pharmaceutical industry due to their antibiotic, anti-inflammatory, antioxidant and UV filter properties. In this work we focused our study on Pseudevenia furfuracea lichen, which is intensively used as a raw material in perfumery and cosmetics (1900 tons/year), due to its large availability in nature as well as possessing various secondary metabolites. In this work we presented extraction of the secondary metabolites using a selective and innovative solventfree method in shorter extraction time in comparison to the conventional extraction methods requiring under reflux of large quantities of solvents with longer times for extraction. The proposed method is based on the use of microwave irradiation for extraction (MIE) associated to (or not) appropriate ionic liquids. Two kinds of hydrophilic or hydrophobic imidazolium- and pyridinium-based ionic liquids (ILs) were synthesized. Three different methods of grinding for lichen were used, leading to different particle size and the crushed products were observed by scanning electron microscopy (SEM). Heating optimization of MIE was performed during 15 min at optimal temperature (75 °C) (instead of 24 h under conventional heating). A comparative study of extraction rates between MIE and extraction with conventional heating was realized with a CAMAG® spectrodensitometer and results of analysis showed that MIE is efficient in most of the studied cases. The use of ionic liquids showed selectivity for extraction and it depended on the structure of ILs and also intermolecular interactions between ILs and extracted substances.Effect of each ionic liquid on the degradation of one of the secondary metabolites, atranorin, was also been studied. In addition, interactions between IL and the surface of the lichen surface were studied by measurements of the angle of contact and by Brunauer Emett and Teller measurements. Scale-up for extraction was carried out to investigate the reproducibility of the method and the possibility of reuse of the ionic liquid

Microwave-green synthesis of AlPO-n and SAPO-n (n = 5 and 18) nanosized crystals and their assembly in layers

International audienceGreen synthesis of nanosized AlPO-n and SAPO-n (n = 5 and 18) crystals with AFI and AEI type structures from non-reacted precursor suspensions with an essential chemical compensation is presented. The crystallization of both materials was accomplished within few minutes (5-18 minutes) instead of several days by replacing the conventional with microwave heating. The nanosized AlPO-n and SAPO-n (n = 5 and 18) crystals were stabilized in coating suspensions and deposited in layers on silicon wafers. It is shown that the AFI-type crystals (one-dimensional pores with a diameter of 0.73 nm) were primarily oriented with (001) direction perpendicular to the substrate, while the AEI-type crystals (three-dimensional pores with a diameter of 0.38 nm) were randomly oriented. The relationship between the crystal orientation and the adsorption behavior of the AFI and AEI layers toward water was studied by GI-XRD and operando IR spectroscopy

Acute Toxicity of Silver Free and Encapsulated in Nanosized Zeolite for Eukaryotic Cells

CERVOXYInternational audienc

Ruthenium tris(2,2′-bipyridyl) complex encapsulated in nanosized faujasite zeolite as intracellular localization tracer

CERVOXYInternational audienceDesigning zeolites for medical applications is a challenging task that requires introducing new functionalities without altering the intrinsic properties such as morphology, crystallinity, colloidal stability, surface charge, and porosity. Herein, we present the encapsulation of luminescent ruthenium-tris(2,2′-bipyridyl) complex in faujasite (FAU) zeolite nanocrystals (Ru(bpy)3-FAU) and their use as an intracellular localization tracer. Upon exciting the Ru(bpy)3-FAU zeolite at 450 nm, the sample gives rise to an orange-red emission at 628 nm, thus permitting its use for cellular imaging and localization of the zeolite nanoparticles. The nanosized Ru(bpy)3-FAU zeolite is characterized in terms of size, charge, crystallinity, morphology, porosity, thermal stability, and sorption capacity. The potential toxicity of Ru(bpy)3-FAU on U251-MG glioblastoma cells was evaluated. A safe concentration (50-100 µg/ml) for the Ru(bpy)3-FAU zeolite is identified. The luminescent properties of the ruthenium complex confined in the zeolite nanocrystals allow their localization in the U251-MG cells with a main accumulation in the cytoplasm. The Ru(bpy)3-FAU nanosized zeolite is a potential candidate for biological applications for being stable, safe, capable of loading respiratory gases, and easily probed in the cells owing to its luminescent properties

A Facile Route toward the Increase of Oxygen Content in Nanosized Zeolite by Insertion of Cerium and Fluorinated Compounds

CERVOXY COLLInternational audienc

Incorporation of trivalent cations in NaX zeolite nanocrystals for the adsorption of O 2 in the presence of CO 2

CERVOXY COLLInternational audienceThe O2 and CO2 sorption properties of nanosized zeolite X with faujasite type structure through a partial ionic exchange of sodium (Na +) by trivalent cations (Gd 3+ and Ce 3+) were evaluated. Three faujasite samples were studied, the as-synthesized Na-X possessing Na + solely, and the modified samples Na-Gd-X and Na-Ce-X containing Gd 3+ (1.8 wt%) and Ce 3+ (0.82 wt%), respectively. Incorporating scarce amounts of trivalent cations modified the adsorption affinity of zeolites towards O2 and CO2 as demonstrated by in situ Fourier-transform infrared spectroscopy (FTIR). While Na-Ce-X encounters the highest O2 physisorption capacity, the Na-Gd-X is adsorbing the highest quantities of molecular CO2. All three samples exhibit the chemisorbed CO2 in the form of carbonates, while the Na-X stores carbonates in monodentate and polydentate forms, the Na-Gd-X and Na-Ce-X allow the formation of polydentate carbonates only. Density functional theory (DFT) calculations revealed that trivalent cations tend to adsorb gases through two cations simultaneously which explains the presence of polydentate carbonates exclusively in the corresponding modified zeolites. The DFT results confirmed the higher affinity of Na-Gd-X and Na-Ce-X nanocrystals towards O2 in the presence of CO2. The affinity of Na-Gd-X and Na-Ce-X nanocrystals towards O2 opens the door of their use as oxygen transporters for medical applications where CO2 is constantly present. The toxicity of the nanosized zeolites and their performance in O2 release are reported too

A new strategy for treatment of glioblastoma via reoxygenation using zeolites nanocrystals

CERVOXYInternational audienc