Promotion effect of rare earth elements (Ce, Nd, Pr) on physicochemical properties of M-Al mixed oxides (M = Cu, Ni, Co) and their catalytic activity in N2O decomposition

A series of M-AlOx mixed oxides (M = Cu, Co, Ni) with the addition of high loadings of rare earth elements (REE, R = Ce, Nd, Pr; R0.5M0.8Al0.2, molar ratio) were investigated in N2O decomposition. The precursors were prepared by coprecipitation and subsequent calcination at 600\ua0\ub0C. The obtained mixed metal oxides were characterized by X-ray diffraction with Rietveld analysis, N2 sorption, and H2 temperature-programmed reduction. Depending on the nature of REE and the initial M-Al system, R cations could be separately segregated in oxide form or coordinated with the transition metal cations and form mixed structures. The addition of Ce3+ consistently led to nanocrystalline CeO2 mixed with the divalent oxides, whereas the addition of Nd3+ or Pr3+ resulted in the formation of their respective oxide phases as well as perovskites/Ruddlesden–Popper phases. The presence of REE modified the textural and redox properties of the calcined materials. The rare earth element-induced formation of low-temperature reducible MOx species that systematically improved the N2O decomposition on the modified catalysts compared to the pristine M-Al materials by the order of Co > Ni > Cu. The Ce0.5Co0.8Al0.2 catalyst revealed the highest activity and remained stable (approximately 90% of N2O conversion) for 50\ua0h during time-on-stream in 1000\ua0ppm N2O, 200\ua0ppm NO, 20 000\ua0ppm O2, 2500\ua0ppm H2O/N2 balance at WHSV = 16 L g−1\ua0h−1

Cell cycle block by p53 activation reduces SARS-CoV-2 release in infected alveolar basal epithelial A549-hACE2 cells

SARS-CoV viruses have been shown to downregulate cellular events that control antiviral defenses. They adopt several strategies to silence p53, key molecule for cell homeostasis and immune control, indicating that p53 has a central role in controlling their proliferation in the host. Specific actions are the stabilization of its inhibitor, MDM2, and the interference with its transcriptional activity. The aim of our work was to evaluate a new approach against SARS-CoV-2 by using MDM2 inhibitors to raise p53 levels and activate p53-dependent pathways, therefore leading to cell cycle inhibition. Experimental setting was performed in the alveolar basal epithelial cell line A549-hACE2, expressing high level of ACE2 receptor, to allow virus entry, as well as p53 wild-type. Cells were treated with several concentrations of Nutlin-3 or RG-7112, two known MDM2 inhibitors, for the instauration of a cell cycle block steady-state condition before and during SARS-CoV-2 infection, and for the evaluation of p53 activation and impact on virus release and related innate immune events. The results indicated an efficient cell cycle block with inhibition of the virion release and a significant inhibition of IL-6, NF-kB and IFN-λ expression. These data suggest that p53 is an efficient target for new therapies against the virus and that MDM2 inhibitors deserve to be further investigated in this field

Location of pharmaceuticals adsorbed from water on Y organophilic zeolite by neutron powder diffraction

In the last decade, it was demonstrated that domestic wastewaters contain a variety of organic contaminants such as pharmaceuticals and personal care products. Most of these compounds undergo both incomplete removal in wastewater treatment plants and slow natural degradation, consequently they are found in surface waters receiving effluent from treatment plants [1]. Pharmaceuticals can also be found in surface waters due to their veterinary use, in such cases they enter the environment via manure dispersion and animal excretion onto soils [2]. Studies on conventional biological drinking-water treatment processes such as biofiltration have shown that they are largely ineffective in removing pharmaceuticals [3]. In literature, several works focused on advantages of zeolites as adsorbents, such as high selectivity, rapid kinetics, reduced interference from salt and humic substances [4], excellent resistance to chemical, biological, mechanical and thermal stress [5-7 and references therein]. Even if zeolites are more expensive with respect to other adsorbents, they offer the possibility to be regenerated without loss of performances at relatively low temperatures [8-10]. In this work, the removal of three different pharmaceuticals (atenolol C14H22N2O3, ketoprofen C16H14O3, diclofenac C14H11Cl2NO2) from water by high-silica organophilic zeolite Y (with a SiO2/Al2O3 ratio equal to 200) will be investigated. All selected drugs differ in chemical properties and molecular dimensions and are ubiquitous contaminants in the sewage waters, while not being effectively removed by conventional activated sludge treatment and membrane bioreactors (MBRs). Despite the large effort devoted to these studies, up to now, a limited number of investigations on drugs-loaded zeolites have been carried out by X-ray or neutron diffraction to obtain the location and population of atoms sites [4-7, 9-10]. The present study is designed to determine the contribution of hydrogen bonding, hydration and dynamics to the thermostability of selected pharmaceuticals adsorbed onto zeolites from water. Neutron diffraction has been shown to be a powerful technique for locating light atoms even at medium resolution. By using the deuterated forms of the target pharmaceuticals almost all accessible labile H atoms (i.e., most of those in O-H and N-H groups) will been replaced by D atoms thus increasing the overall scattering power of the crystal for neutrons and cancelling the negative scattering density of H atoms which tends to reduce the positive density of other atoms. Additionally, deuteration also reduces the incoherent scattering from hydrogen in the sample as well as the background scattering thus increasing the diffraction signal. Finally, the extent of H/D exchange in the OH/COOH groups, as determined in neutron Fourier maps, directly reflects local dynamics in the drugs structure. This experimental technique has already been used by our group to determine the population and location of hydroxyls in deuterated and calcined D-ferrierite [11-12], mordenite [13] and heulandite [14] and very recently zeolite L (proposal 5-22-744 ) by using the data collected at D2B beamline (ILL, Grenoble). The aim of this proposal is to determine the number and location of adsorbed-drugs sites in zeolite Y, the synthetic counterpart of natural faujasite, via powder neutron diffraction. Zeolite Y is a large pore material which crystallizes in the cubic space group Fd-3m, with a lattice constant ranging from about 24.2 to 25.1 A, depending on the framework aluminium concentration, cations, and state of hydration. The pore structure is characterized by approximately 12A diameter cages, linked through access windows ( 7.0A×7.1A in diameter) and thus permitting quite large molecules to enter, making this structure potentially useful in the adsorption of thedrugs under study. The sample to be used in this project is a synthetic commercial zeolite Y (code HSZ-390HUA) with a 200 SiO2/Al2O3 (mol/mol) ratio, purchased in its protonated form from the Tosoh Corporation (Japan). We plan to collect three samples of zeolite Y powders (Atenolol-Y, diclofenac-Y and ketoprofen-YL, respectively). In particular, all samples will be obtained by the ion exchanging the as-synthesized form with deuterated drugs in aqueous solution for ≈140 h at room temperature and then washed with D2O. All samples will be packed in our laboratory in an argon-flushed glove-bag into a vanadium container sealed with a rubber gasket to ensure humidity-free transport to the neutron source. Powder diffraction data will be preferentially collected at the D2B beamline, with satisfactory counting statistics in order to allow full Rietveld refinements of all datasets. The powder data will be processed using the GSAS package. The location of extraframework species will be carried out by a combination of least squares and Difference Fourier map techniques. To achieve these results high resolution at high-q is mandatory to obtain powder diffraction data for accurate Rietveld refinement. The proposed D2B instrument will dramatically expand the knowledge of drugs adsorption on zeolites, allowing large chemical complexes and a range of pharmaceuticals to be studied. References [1] Martucci, A., Braschi, I., Marchese, L., & Quartieri, S. (2014) Mineral. Mag., 78(5), 1115. [2] Figueroa R.A., Leonard A., MacKay A.A. (2004) Environ. Sci. Technol. 38, 476. [3] Ternes T.A., Meisenheimer M., McDowell D., Sacher F., Brauch H.J., Haist- Gulde B., Preuss G., Wilme U., Zulei-Seibert N. (2002) Environ. Sci. Technol. 36, 3855. [4] Braschi I., Martucci A., Blasioli S., Mzini L. L., Ciavatta C., & Cossi M. (2016) Chemosphere, 155, 444. [5] Martucci A., Pasti L., Marchetti N., Cavazzini A., Dondi F., Alberti A. (2012) Micro. Meso. Mater. 148, 174. [6] Pasti L., Sarti E., Cavazzini A., Marchetti N., Dondi F., Martucci, A. (2013) J. Sep. Sci. 36, 1604.[7] Braschi I., Blasioli S., Gigli L., Gessa C.E., Alberti A., Martucci A. (2010) J. Hazard. Mater. 17, 218. [8] Rodeghero E., Martucci A., Cruciani G., Bagatin R., Sarti E., Bosi V., Pasti L. (2016) Catal. Today 227, 118. [9] Martucci A., Rodeghero E., Pasti L., Bosi V., Cruciani G. (2015) Micro. Meso. Mater. 215, 175. [10] Braschi I., Blasioli S., Buscaroli E., Montecchio D., & Martucci A. (2016). J. Env. Sciences, 43, 302. [11] Martucci A., Alberti A., Cruciani G., Radaelli P., Ciambelli P., Rapacciuolo M., (1999) Micro. Meso. Mater., 30, 95. [12] Alberti A. and Martucci A. (2010) J. Phys. Chem. C 114, 7767. [13] Martucci A., Cruciani G., Alberti A., Ritter C., Ciambelli P., Rapacciuolo M., (2000) Micro. Meso. Mater. 35–36, 405. [14] Martucci A., Parodi I., Simoncic P., Armbruster T., Alberti A. (2009), Micro. Meso. Mater. 123, 15.pharmaceuticals, Y organophilic zeolite, neutron powder diffractio

ENTRAPPING OF IBUPROFEN AND ATENOLOL WITHIN Y ZEOLITE: A NEUTRON POWDER CHARACTERIZATION AFTER DRUGS ADSORPTION

Pharmaceuticals products are considered to be among the most common organic wastewater contaminants due to their widespread use and slow natural degradation, which still makes their complete removal from water a challenging task. Due to their unique properties, zeolites have already proved their efficiency as sorbent materials in wastewater treatments. Based on the excellent results obtained, it has been decided to study the removal of two pharmaceutical products (ibuprofen and atenolol) from aqueous solution by organophilic zeolite Y (Si/Al ratio=200). The aim was to determine the zeolite efficiency in adsorption processes of pharmaceutical compounds characterized by high molecular dimensions. Results gained suggest that Y zeolite could be successfully used as sorbent material in water remediation processes from drugs

Insights into adsorption of chlorobenzene in high silica MFI and FAU zeolites gained from chromatographic and diffractometric techniques

In this work, the capability of two commercial high silica zeolites (HSZs), namely ZSM-5 and Y, for the removal of chlorobenzene (CB) from water was investigated by combining chromatographic and diffractometric techniques. The adsorption isotherms and kinetics of CB on ZSM-5 and Y zeolites were determined from batch tests. The adsorption kinetics were very fast; the time to reach equilibrium was less than 10 min. The equilibrium data of CB on the two HSZs showed dissimilarities that are particularly evident in the adsorption data concerning the low concentration range, where Y zeolite is characterized by low adsorption. On the contrary, at higher solution concentrations the adsorption capacity of Y is higher than that of ZSM-5. The crystalline structures of Y and ZSM-5 saturated with CB were investigated by X-ray diffraction (XRD) techniques. Rietveld refinement analyses of XRD data allowed for quantitative probing of the structural modifications of both zeolites after CB adsorption and provided insight into the preferred zeolite adsorption sites in both microporous materials. The refined frameworkâ\u80\u93extraframework bond distances confirm that interactions between the selected organic contaminant and hydrophobic zeolites are mediated via co-adsorbed H2O. The occurrence of H2Oâ\u80\u93CBâ\u80\u93framework oxygen oligomers explains variations in both the unit cell parameters and the shape of the channels, clearly confirming that water plays a very relevant role in controlling the diffusion and adsorption processes in hydrophobic zeolites

EXPLORING THE EFFECT OF TEMPERATURE ON GA-DOPED ZEOLITE CATALYSTS BY IN SITU SYNCHROTRON X-RAY POWDER DIFFRACTION

Gallium-containing zeolites have been extensively investigated due to their unique catalytic performances in light hydrocarbon aromatization. Newest applications concern the conversion of biomass into biofuels and bio-based chemicals. These Ga-doped catalysts can be prepared by post synthesis methods, including impregnation, ion exchange or Chemical Vapor Deposition (CVD). The complex mechanism of galliation by post synthesis treatment is suitable to introduce gallium into both tetrahedrally coordinated framework and interstitial non-framework positions. Brønsted acidity within zeolites is generated when tetravalent Si4+ is replaced with trivalent Ga3+. Oxo cations GaO+ on exchange positions of the framework behave as Lewis acids. Non-framework gallium is the source of Lewis acidity. Thermal treatments cause the migration of Ga3+ to extraframework positions and its progressive aggregation in form of isolated, dimeric and polymeric species up to oxide nanoparticles. This migration leads to the appearance of a different type of acid sites of Lewis nature. As a consequence, after this treatment Ga-zeolites can possess both Brønsted and Lewis acid sites, working separately or in a synergistic way in acid catalyzed reactions. In spite of the growing interest on the nature of gallium species in Ga-catalysts, there is a lack of in situ studies of Ga-zeolite systems at the high temperature range, where they exhibit their catalytic activity. To predict catalysts behaviour at non-ambient conditions is mandatory to improve their effectiveness and prevent from a possible deactivation, which is still a challenging task. To ensure the long-term stability during catalytic reactions, detailed information about catalyst modifications upon thermal treatment are required. In particular, a better understanding of extraframework metal cations nature and the way they contribute to catalytic reactions is of primary importance to support the design of high-performing Ga-zeolite catalysts, at whose request in the industrial field is continuously growing. In spite of that, the particular role of the framework and non-framework gallium is still very controversial. As a result, the nature of the catalytically active sites in Ga-zeolites as well as the possible cooperative effects (framework and non-framework gallium) and the evaluation of their stability under operating conditions remain debatable

Adsorption of L-lysine on zeolites: effect of different framework topology and different Si/Al ratio

The study of the ability of zeolites to adsorb amino acids is significant to improve the knowledge of the interactions between these molecules and solid surfaces. This is of fundamental importance to increase the level of understanding of much more complex systems and to select adsorbent materials able to selectively capture amino acids from aqueous solutions.[1] Zeolites are aluminosilicate materials characterized by regular crystalline structure with microporous cavities which confer a high superficial area. The physico-chemical proprieties of zeolites depend on the composition of their framework that consist of tetrahedral units of SiO4 and AlO4 and, in particular, their ratio (SAR) characterizes the hydrophilic/hydrophobic behavior of the material. Moreover, the different conformation and dimension of the internal channels and cages influence the adsorption selectivity towards host molecules.[2] The ability of zeolites to adsorb biologically active biomolecules such as amino acids is of particular interest in industrial biotechnology[3] due to the fact that these adsorbent materials could be used as solid solvents to stabilize the different charged forms of the amino acids. In this study we tested the different adsorption capacity of zeolites L and ZSM-5 towards the amino acid L-lysine. These zeolites were chosen since they present different framework, with 2D and 3D channels structures, and different pore dimensions. Moreover, for the zeolite ZSM-5, two materials having different SAR were selected to study the effect of zeolite chemical composition on the adsorption capacity. Kinetic and isothermal experiments were carried out at different L-lysine initial concentrations to study the adsorption processes. The results show high capacity towards the adsorption of L-lysine for every zeolite investigated. We found a higher capacity for zeolite L with respect to ZSM-5. Moreover, zeolite ZSM-5 with greater SAR has shown less adsorption, probably a cause of different surface charge. [1][4] Moreover, the results obtained by thermal analyses (TGDTG- DTA) showed different interactions within the amino acid-zeolite adduct and different stability, depending on the peculiarities of the zeolites studied. Further investigation of the refinements of X ray powder diffraction patterns showed the adsorption sites, the orientation and the interactions of the amino acid molecules within the zeolite channels. This work allowed to improve the understanding of the formation and interactions of the adducts that originate from the adsorption of amino acids on zeolites. The information obtained are useful for separation of amino acids from complex mixtures. [1] G. Beltrami, A. Martucci, L. Pasti, T. Chenet, M. Ardit, L. Gigli, M. Cescon, E. Suard, ChemistryOpen 2020, 9(10), 978–982. [2] A. Martucci, L. Pasti, N. Marchetti, A. Cavazzini, F. Dondi, A. Alberti, Micropor. Mesopor. Mat. 2012, 148(1), 174-183. [3] K. Stückenschneider, J. Merz, and G. Schembecker, J. Phys. Chem. 2014, 118, 5810-5819. [4] T. Chenet, A. Martucci, M. Cescon, G. Vergine, G. Beltrami, L. Gigli, M. Ardit, M. Migliori, E. Catizzone, G. Giordano, L. Pasti, Micropor. Mesopor. Mat., 2021, 323, 111183

Organic guests within a ferroelastic host: the case of high silica zeolite ZSM-5

The physical–chemical properties of guest molecules confined within a zeolite framework host are known to be strongly affected by the confinement effects exerted through noncovalent host–guest interactions. On the basis of synchrotron time-resolved powder diffraction measurements and the Landau theory of ferroelastic phase transitions, we provide in this work evidence for the strong coupling existing between the thermodynamic properties of organic molecules (toluene, 1,2-dichloroethane, methyl-tert-butyl-ether) adsorbed within the ZSM-5 zeolite and the lattice strain driving the monoclinic-to-orthorhombic (ferroelastic-to-paraelastic) phase transition which controls connectivity and diffusivity in the zeolite framework