Lara Gigli

Removal of sulfonamide antibiotics from water: Evidence of adsorption into an organophilic zeolite Y by its structural modifications

Sulfonamide antibiotics are persistent pollutants of aquatic bodies, known to induce high levels of bacterial resistance. We investigated the adsorption of sulfadiazine, sulfamethazine, and sulfachloropyridazine sulfonamides into a highly dealuminated faujasite zeolite (Y) with cage window sizes comparable to sulfonamide dimensions. At maximal solubility the antibiotics were almost completely (>90%) and quickly (t<1min) removed from the water by zeolite. The maximal amount of sulfonamides adsorbed was 18-26% DW of dry zeolite weight, as evidenced by thermogravimetric analyses and accounted for about one antibiotic molecule per zeolitic cage. The presence of this organic inside the cage was revealed by unit cell parameter variations and structural deformations obtained by X-ray structure analyses carried out using the Rietveld method on exhausted zeolite. The most evident deformation effects were the lowering of the Fd-3m real symmetry in the parent zeolite to Fd-3 and the remarkable deformations which occurred in the 12-membered ring cage window after sulfadiazine or sulfachloropyridazine adsorption. After sulfamethazine adsorption, zeolite deformation caused a lowering in symmetry up to the monoclinic P2/m space group. The effective and irreversible adsorption of sulfonamides into organophylic Y zeolite makes this cheap and environmentally friendly material a suitable candidate for removing sulfonamides from water.

Removal of sulfamethoxazole sulfonamide antibiotic from water by high silica zeolites: A study of the involved host-guest interactions by a combined structural, spectroscopic, and computational approach

Sulfonamide antibiotics are persistent pollutants present in surface and subsurface waters in both agricultural and urban environments. Sulfonamides are of particular concern in the environment because they are known to induce high levels of bacterial resistance. Adsorption of sulfamethoxazole sulfonamide antibiotic into three high silica zeolites (Y, mordenite, and ZSM-5) with pore opening sizes comparable to sulfamethoxazole dimensions is reported. Sulfamethoxazole was almost completely removed from water by zeolite Y and MOR in a few minutes. Adsorption onto ZSM-5 showed an increased kinetics with increasing temperature. Antibiotic sorption was largely irreversible with little antibiotic desorbed. Sulfamethoxazole incorporation and localization into the pore of each zeolite system was defined along with medium-weak and cooperative host-guest interactions in which water molecules play a certain role only in zeolite Y and mordenite.

Irreversible Conversion of a Water–Ethanol Solution into an Organized Two-Dimensional Network of Alternating Supramolecular Units in a Hydrophobic Zeolite under Pressure.

Turning disorder into organization is a key issue in science. By making use of X-ray powder diffraction and modeling studies, we show herein that high pressures in combination with the shape and space constraints of the hydrophobic all-silica zeolite ferrierite separate an ethanol-water liquid mixture into ethanol dimer wires and water tetramer squares. The confined supramolecular blocks alternate in a binary two-dimensional (2D) architecture that remains stable upon complete pressure release. These results support the combined use of high pressures and porous networks as a viable strategy for driving the organization of molecules or nano-objects towards complex, pre-defined patterns relevant for the realization of novel functional nanocomposites.

A new soluble and bioactive polymorph of praziquantel

Graphical abstract Figure. No caption available. &NA; Praziquantel is the only available drug to treat Schistosomiasis. However, its utilization is limited by many drawbacks, including the high therapeutic dose needed, resulting in large tablets and capsules difficult to be swallowed, especially from pediatric patients. In this study, an alternative option to overcome these disadvantages is proposed: to switch to a novel crystalline polymorph of racemic compound praziquantel. The preparation of the crystalline polymorph was realized via a neat grinding process in a vibrational mill. The new phase (Form B) was chemically identical to the starting material (as proved by HPLC, 1H NMR, and polarimetry), but showed different physical properties (as evaluated by SEM, differential scanning calorimetry, thermogravimetry, ATR‐FTIR spectroscopy, X‐ray powder diffraction, and solid‐state NMR). Furthermore, the crystal structure of the new phase was solved from the powder synchrotron X‐ray diffraction pattern, resulting in a monoclinic C2/c cell and validated by DFT‐D calculation. Moreover the simulated solid‐state NMR 13C chemical shifts were in excellent agreement with the experimental data. The conversion of original praziquantel into Form B showed to affect positively the water solubility and the intrinsic dissolution rate of praziquantel. Both the in vitro and in vivo activity against Schistosoma mansoni were maintained. Our findings suggest that the new phase, that proved to be physically stable for at least one year, is a promising product for designing a new praziquantel formulation.

The crystal structure of mineral fibres: 2. Amosite and fibrous anthophyllite

This study reports for the first time crystal-structure data for amosite and fibrous anthophyllite. The chemical composition of the two fibre species was determined from EMPA. Crystal structures were refined using powder-diffraction data, using both laboratory sources and synchrotron radiation. Results were compared with the available literature data for the non-fibrous varieties grunerite and anthophyllite, respectively. The calculated site-occupancies for all samples are in agreement with the chemical compositions calculated from EMPA. The existing structure models of grunerite and orthorhombic anthophyllite also applies to the corresponding fibrous varieties amosite and fibrous anthophyllite, respectively. In amosite, both Fe2+ and Fe3+ atoms are found at the sites M(1), M(2) and M(3) and Fe2+ ions is the only atomic species found at site M(4). Mg is disordered over the C sites with a preference for site M(2). Minor Ca and Na have been assigned to the A site. In fibrous anthophyllite, Mg is the only atomic species found at the M1, M2 and M3 sites. Fe2+, Mg (and minor Mn) have been assigned to the M4 site, whereas minor Ca has been assigned to the A site. In both structures, the environment at the M(4) site in amosite and M4 site is in fibrous anthophyllite highly distorted. This work can be considered a basis for studies aimed at understanding the potential toxicity/pathogenicity of these mineral fibres.

Thermal expansion of boron subnitrides

Abstract The lattice parameters of two boron subnitrides, B13N2 and B50N2, have been measured as a function of temperature between 298 and 1273u202fK, and the corresponding thermal expansion coefficients have been determined. Thermal expansion of both boron subnitrides was found to be quasi-linear, and the volume thermal expansion coefficients of B50N2 (15.7 (2)u202f×u202f10−6u202fK−1) and B13N2 (21.3 (2)u202f×u202f10−6u202fK−1) are of the same order of magnitude as those of boron-rich compounds with structure related to α-rhombohedral boron. For both boron subnitrides no temperature-induced phase transitions have been observed in the temperature range under study.

MCX@Elettra: powder diffraction in ambient and non-ambient conditions

The beamline Material Characterization by X-ray diffraction (MCX), is the general purpose powder diffraction beamline at the Elettra synchrotron in Trieste, one of currently four diffraction beamlines at Elettra . The beamline is designed to host a wide range of experiments, that cover many scientific fields with standard applications such as phase identification, structure determination, residual stress measurements and line profile analysis. The experimental station houses a four circle Huber diffractometer. The two-theta arm can be equipped with a scintillator detector either with slits or with a Si 111 analyzer crystal. A multichannel analyzer is also available, which can be used to eliminate the background signal resulting from the fluorescence of the sample in a diffraction experiment, or can be used to perform chemical analysis on samples. Alternatively, a ccd detector can be installed on the arm, which is especially useful in the case of in operando studies on for example batteries, where changes in the diffraction pattern in a range of 2-theta can be followed instantaneously while the battery is operating. A hot air blower and a cryo stream are available to measure powder samples in capillaries from 100 to 1273 K. As a second experimental setup a furnace has been installed, which has been designed for powder diffraction measurements at high temperature (up to 1373 K at the present state). Around the measurement region the geometry of the radiative heating element assures a negligible temperature gradient along the capillary and can accommodate either powder samples in capillary or small flat samples. A double capillary holder allows a flow of gas in the inner sample capillary while the outer one serves as the reaction chamber. The furnace is coupled to a translating curved imaging-plate detector, allowing the collection of diffraction patterns up to 130 degrees two-theta in order to follow chemical reactions and phase transformations. Here the current status of the beamline will be presented illustrated by recent experiments using the different setups available at MCX. A room temperature and high temperature structural studies have been performed through the whole compositional range of the (Ce1–xMx)O2–x/2 for M = Sm, Gd and Lu revealing a complicated hybrid structural behavior. The relation between microstructure and thermoluminiscence of LiF2 has been investigated using both the funcace and the hot air blower. Finally, the phase diagram at high temperature Cu-TiS2 has been studied using the furnace in an inert atmosphere.

Supramolecular organization of water–ethanol solution in ferrierite under pressure

Simona Quartieri1, Rossella Arletti2, Lara Gigli3, Giovanna Vezzalini4, Ettore Silvestro Fois5, Tabacchi Gloria5 1MIFT Department, University Of Messina (Italy), Messina S. Agata, Italy, 2University of Torino, Department of Earth Sciences, Torino, Italy, 3Elettra Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy, 4Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Modena, Italy, 5Dipartimento di Scienza ed Alta Tecnologia, Università dell’Insubria and INSTM, Como, Italy E-mail: squartieri@unime.it