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Erionite is the name for a zeolite mineral series originating from diagenesis or hydrothermal alteration of volcanic rocks. The particular erionite “species” is based on the dominant extra-framework cation, erionite-Ca, erionite-K, or erionite Na. Irrespective of the species, erionite can display a fibrous/asbestiform morphology and has been linked with cases of malignant mesothelioma, a disease typically associated with asbestos exposure. Characterization of new discoveries of erionite is therefore important to assess any potential exposure hazards. This study describes a new asbestiform erionite from vesicles within the Upper Cretaceous Mt. Somers Volcanics Group (MSVG), Canterbury, New Zealand. The erionite is within the Hinds River Dacite, the youngest unit within the MSVG at Gawler Downs, ~100 km west of Christchurch, in the foothills of the Southern Alps. A multi-analytical approach was taken to analyze the sample which included micro-Raman spectroscopy, thermogravimetric analysis, electron microscopy, electron microprobe analysis, and X-ray powder diffraction with the Rietveld method. Results confirmed the mineral as fibrous erionite-K. The chemical composition of the mineral is unique due to the presence of higher levels of Mg. While Fe was also identified, this was due to smectite flakes occurring on the surface of the erionite fibers. According to the World Health Organization (WHO) respirable mineral fiber definition, where length ≥5 μm. width ≤3 μm, and aspect ratio (L/w) ≥3:1, the Gawler Downs erionite fibers are respirable, while the fibers themselves exceed respirable thickness. In addition to morphology, a value for the potential toxicity model was computed to be 2.28 for the Gawler Downs erionite. This is similar to those of other carcinogenic erionites from Karain, Turkey (2.33), and Nevada, U.S.A. (2.28). Taken together, results indicate Gawler Downs erionite represents an environmental hazard. Nevertheless, further investigation is required to determine potential environmental exposure pathways by which erionite may become airborne and assess the actual environmental risk in the Gawler Downs area.

In this contribution, we tried to shed light on the molecular structure of octyl methoxycinnamate (octinoxate, OMC) adsorbed in NaX zeolite, which represents a promising hybrid UV filter system. The combination of infrared spectroscopy and density functional theory modeling was crucial to identify all the complex host–guest interactions and to unveil that, although slightly thermodynamically unfavored, OMC is dominantly present in the trans-form inside the NaX framework. We also showed that the interaction between the zeolite Na cations and the OMC molecule is the key feature that determines the stability and efficacy of these hybrid UV filters. These findings confirm that cationic zeolites are promising materials for the encapsulation of UV filters to decrease their negative impact on the environment and their photochemical instability.

Germanium is known to occupy tetrahedral sites by substituting silicon in germanosilicate zeolites. In this study, we present pioneering findings regarding the synthesis of zeolites with an MFI structure (GeMFI) incorporating a high germanium amount (16% Ge). Remarkably, the germanium atoms feature a slight electron deficiency with respect to GeO2, and the typical coordination number of 4, as usually reported for the germanosilicate zeolites, is exceeded, giving rise to Ge dimers in a double-bridge configuration. Notably, the compensation of the ammonium template is achieved not through fluorine ions in the [415262] cages of the framework, as conventionally considered, but rather through oxygen. The GeMFI zeolite with the high Ge content reported in this work demonstrated exceptional thermal and hydrothermal stability, surpassing up to 1050 °C, thanks to both the double-bridge configuration and the defect-free structure. The unexpected role of germanium in MFI zeolite challenges previous assumptions, representing a paradigm shift in the understanding of porous germanosilicate structures, paving the way for a reevaluation of their synthesis, hydrolysis, and potential applications.

Recently, filling zeolites with gaseous hydrocarbons at high pressures in diamond anvil cells has been carried out to synthesize novel polymer-guest/zeolite-host nanocomposites with potential, intriguing applications, although the small amount of materials, 10–7cm3, severely limited true technological exploitation. Here, liquid phenylacetylene, a much more practical reactant, was polymerized in the 12 Å channels of the aluminophosphate Virginia Polytechnic Institute—Five (VFI) at about 0.8 GPa and 140 °C, with large volumes in the order of 0.6 cm3. The resulting polymer/VFI composite was investigated by synchrotron X-ray diffraction and optical and 1H, 13C, and 27Al nuclear magnetic resonance spectroscopy. The materials, consisting of disordered π-conjugated polyphenylacetylene chains in the pores of VFI, were deposited on quartz crystal microbalances and tested as gas sensors. We obtained promising sensing performances to water and butanol vapors, attributed to the finely tuned nanostructure of the composites. High-pressure synthesis is used here to obtain an otherwise unattainable true technological material.

The insertion of H2O in the siliceous zeolites TON (Theta-one) and MFI (Mobil Five) was studied at pressures up to 0.9 GPa by synchrotron X-ray diffraction, infrared spectroscopy, and Monte Carlo modeling. TON (orthorhombic, Cmc21) and MFI (monoclinic, P21/n) have 1D and 3D pore systems, respectively. H2O insertion was quantified by a combination of structure refinements and Monte Carlo modeling. Complete pore filling is observed at 0.9 GPa in the high-pressure forms of TON (orthorhombic, Pbn21) and MFI (orthorhombic, Pnma). This corresponds to more than twice as many H2O molecules per SiO2unit in the 3D pore system of MFI than in the 1D pore system of TON. This results in a greater swelling of the MFI system as compared to the TON system upon insertion. In both cases, both experiments and modeling indicate that the density of water in the pores is close to that of bulk water at the same pressure. A greater degree of molecular disorder is observed in the 3D H2O network of MFI. Infrared spectroscopy indicates a weakening of the hydrogen bonds associated with geometrical constraints because of confinement. The majority of the H2O molecules are extruded on pressure release, indicating that this insertion is reversible to a great extent, which gives rise to the molecular spring properties of these materials.

The host–guest and guest–guest interactions governing the CO2adsorption/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 CO2adsorption/desorption in the FAU zeolites at different levels, that is, average structure by XRPD versus local structure by FTIR spectroscopy . The presence of physisorbed CO2molecules in both zeolites was detected by XRPD, whereas only a high amount of chemisorbed CO2in 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 CO2from both nanosized zeolites; on the contrary, high temperature is required to remove the chemisorbed species from the nanosized Na–X zeolite. Understanding the CO2sorption behavior and capacity of nanosized zeolites is of great importance in broadening their use in environmental, clinical, and biomedical applications.

In this paper, we report the results of the first study focused on the thermal stability and dehydration dynamics of the natural zeolite mineral ferrierite. A sample from Monastir, Sardinia [(Na0.56K1.19Mg2.02Ca0.52Sr0.14) (Al6.89Si29.04)O72·17.86H2O; a= 19.2241(3) Å; b= 14.1563(2) Å; c= 7.5106(1) Å, V= 2043.95(7) Å3] was investigated by thermogravimetric analysis and in-situ synchrotron X‑ray powder diffraction. Thermogravimetric data show that H2O release begins already in the range 50–100 °C and is complete at ~600 °C. The results of the structure refinements performed in Immmspace group by Rietveld analysis with data collected up to 670 °C show that ferrierite belongs to the group of zeolites that do not undergo phase transitions. Upon heating to 670 °C, ferrierite behaves as a non-collapsible structure displaying only a slight contraction of the unit-cell volume (ΔV= –3%). The unit-cell parameter reductions are anisotropic, more pronounced for athan for band c(Δa= –1.6%; Δb= –0.76%; Δc= –0.70%). This anisotropic response to a temperature increase is interpreted as due to the presence in the ferrierite framework of five-membered ring chains of SiO4tetrahedra, which impart a higher structural rigidity along band c. Upon dehydration we observe: (1) the gradual H2O loss, beginning with the molecules hosted in the 10MR channel, is almost complete at 670 °C, in good agreement with the TG data; (2) as a consequence of the decreased H2O content, Mg and K migrate from their original positions, moving from the center of the 10MR channel toward the walls to coordinate the framework oxygen atoms. The observation of transmission electron microscopy selected-area electron diffraction patterns revealed defective crystals with an occasional and moderate structural disorder. Beyond providing information on the thermal stability and behavior of natural ferrierite, the results of this work have significant implications for possible technological applications. These data allow for comparison with the dehydration kinetics/mechanisms of the corresponding synthetic phases, clarifying the role played by framework and extra-framework species on the high-temperature behavior of porous materials with ferrierite topology. Moreover, the information on the thermal behavior of natural ferrierite can be used to predict the energetic performances of analogous synthetic Si-pure counterparts, namely “zeosil-electrolyte” systems, under non-ambient conditions. Specifically, the very high thermal stability of ferrierite determined in this study, coupled with the baric behavior determined in other investigations, suggests that the “Si-FER–electrolyte” system may be an excellent candidate for use as an energy reservoir. Indeed, ferrierite exhibits the so-called “spring behavior,” i.e., upon compression in water or in an electrolyte solution, it converts the mechanical energy into interfacial energy, and—when pressure is released—it can completely restore the supplied mechanical energy accumulated during the compression step.

We have performed a structural investigation of the high pressure intrusion/extrusion of a series of electrolyte aqueous solutions (NaCl, NaBr, and CaCl2) with different concentrations (2 and 3 M) in a pure-silica chabazite. In situ synchrotron X-ray powder diffraction experiments were performed in the pressure range of 0.12–2.6 GPa and upon pressure release, to unravel the interactions among intruded species and host material. The energetic performances of the systems were determined by porosimetric studies. Results show that the chemical nature of saline solution influences the intrusion–extrusion pressure, whereas the structural evolutions undergone by the systems upon pressure-induced intrusion are essentially independent of the nature of the penetrating media. Moreover, the initial electrolyte concentration influences only the value of the intrusion pressure, but neither the amount nor the interaction mode of the intruded species. Both water and salt molecules enter the pores and the penetration of comparable extra-framework volumes occurs at similar pressure values. However, the composition of the intruded species is different from that of the initial solution and depends on the applied pressure, thus reinforcing the hypothesis on ion desolvation under penetration into the pores. After pressure release, pure-silica chabazite intruded by NaCl and NaBr aqueous solutions does not recover the initial cell volume and partially retains the intruded extra-framework species. On the contrary, the zeolite intruded by CaCl2recovers the original cell parameters. These differences have been structurally interpreted on the basis of the electrolyte/zeolite interactions. Interestingly, the extrusion behavior was found to be mainly determined by the interactions of the anion with silanol defects of the chabazite framework, rather than by the coordination bonds of the cation with the framework oxygen atoms.

The interest for the environmental, industrial and technological applications of Si-rich zeolites is very high. Among the large-pore zeolites, faujasite is one of the most exploited. The aim of this paper is to obtain detailed structural information on natural and NH4-exchanged faujasite before using this zeolite for dealumination tests, targeting the realization of large single crystals of all-silica faujasite. As one of the most Si-rich natural samples, faujasite from Sasbach (Na13.64K0.87Mg10.46Ca8.89Sr0.34(Al51.95Si139.57)O384·272.29 H2O; space group Fd-3m;a?=?24.6906(2)?Å) was chosen for study. Single-crystal X-ray diffraction structural refinements of both natural and NH4-exchanged samples are reported and discussed. In the natural faujasite sample, almost all the extraframework species could be located for the first time. In the NH4-exchanged sample the ammonium and water molecule sites were located. Ammonium cations occupy two of the sites occupied by the extraframework species in the original mineral.

Confinement-driven self-assembly of dyes in nanomatrices is an effective route for the production of hybrid supramolecular structures of high technological relevance, among which the archetypal zeolite L based systems are exploited in Förster resonance energy transfer (FRET) sensitized solar cells, luminescent solar concentrators, and color-changing media but also in sensing in analytical chemistry, biology, and diagnostics. Despite this progress in applications, the organization of confined chromophores in zeolite L materials remains elusive. Herein, by integrating experiments with different time scale and radiation source (IR, XRPD, total scattering) with first-principles DFT modeling, we attained a microscopically detailed picture of a technologically important hybrid composite of zeolite L with a perylene–diimide (also known as perylene–bisimide) dye at both hydrated and anhydrous conditions. The asymmetric positioning of the dye in the zeolite channel is determined by two factors: shape-volume constraints, and relative strength of competitive interactions among confined species. Our multitechnique experimental-theoretical approach thoroughly described the supramolecular chemistry of this hybrid material, identifiying possible strategies to further enhance FRET efficiency and improve functionality. This work deepens the understanding of host–guest interactions in dye–zeolite L composites, a key requirement to master the finely tuned mechanisms governing supramolecular organization in confined nanospaces.

The beginning of the 1st millennium BC was one of the key periods in the development of glassmaking technologies, characterized by the supplanting of plant-ash technology by natron-based production, which would be typical of the Roman glass industry. The ESEM-EDS, EMPA, and LA-ICPMS analyses of 72 glass samples from Sarno, Cuma and Capua (Campania, southern Italy), dated to the 9th –6th century BC, revealed a complex picture as regards both the chemical composition of the glass and the trade routes of Early Iron Age Campania. The sample set was composed of classic natron glass, natron black glass (characterised by high levels of FeO =10 wt%), natron alumina-cobalt blue glass coloured with Egyptian cobaltiferous alum, and plant-ash glass. The traceelement analysis made it possible to hypothesize the trade routes that linked ancient Campania with the Eastern Mediterranean.

The process of light conversion is at present deeply investigated to develop more efficient devices for artificial photosynthesis, water splitting, photovoltaic applications, and targeting therapeutic agents. This process is induced by nanostructured functional materials, such as zeolites light sensitized by dye molecules adsorbed into their pores. Here a detailed study of the organization of the cationic dye thionine (Th) inserted into the linear 12MR channels of zeolite L is carried out by XRPD, FT-IR spectroscopyfor the determination of the host–guest interactionsand UV–vis absorption and photoluminescence spectroscopies for the investigation of the electronic states of the guest. Two composites with different Th loading (labeled ZL/0.15Th and ZL/0.27Th) were obtained through ion exchange. TGA spectra and IR-ATR spectroscopy clearly indicated penetration of Th molecules into the ZL channels. Rietveld structural refinement showed that Th molecules in both composites are aligned parallel to the 12MR channel axis and located on the mirror planes parallel to the c-axis. Water molecules interact strongly with the dye and form a kind of solvent–matrix tube shaped around the Th molecule, favoring the upright arrangement of the molecules. DR–UV–vis spectra of the ZL/Th composites indicated that Th molecules are hosted in the ZL channels in a monomeric form. Photoluminescence spectroscopy demonstrated that photoluminescent dyes correspond to ca. 5% of the total amount of Th molecules in the zeolite porosities. While most of the photoluminescent Th molecules exhibit a lifetime equivalent to Th in solutions, the complementary fraction of photoluminescent Th exhibit significantly longer lifetimes, resulting from an entrapment in defects of the zeolite structure, inducing strong rotational constraints to the molecules.

This study presents the results of an archaeometrical investigation of Bronze Age vitreous materials from the archaeological site of Punta di Zambrone (Calabria, southern Italy). The analyses of a set of samples (9 faience beads, 1 glassy bead) from approximately 1200 BCE (Recent Bronze Age) were carried out with an environmental scanning electron microscope (ESEM) and LA-ICPMS (for the glassy bead) following a non-destructive protocol. Only very small chips of faience were sampled for X-ray powder diffraction (XRPD) and preparation of thin sections for ESEM analysis. The glassy bead is an opaque light-blue silica-soda-lime type with an uncommon chemical composition, comparable to some coeval Italian and Mycenaean glassy faience artefacts. These are called LMLK (low magnesium low potassium) glassy faience, but the flux used for their production has not yet been identified. The trace-element analysis allows exclusion of a Mesopotamian or Egyptian provenance for this sample, suggesting it was produced with rather impure raw materials. The nine faience beads have suffered from extensive weathering. The microstructural examinations carried out with the ESEM enabled definition of three different groups: (1) light beads consisting almost entirely of quartz crystals without any original interparticle glass, which could be due to the heavy weathering; (2) dark beads with a high content of manganese and iron oxide and scarce presence of interparticle glass in the body, suggesting the original presence of Mn/Fe-rich interparticle glass; this presence indicates that a glazing mixture containing alkalis and colorants was mixed with quartz, therefore the efflorescence method could have been used for glazing, in combination with either cementation or application glazing (hybrid glazing methods); and (3) one green sample exhibiting an heterogeneous body rich in Mg, K, Ti, and Fe but not containing Mn. The XRPD analysis of a faience bead of group 1 confirmed the exclusive presence of quartz, whereas for group 2, an additional small peak compatible with Mn oxide (Possibly hausmannite) was observed. Considering the colorant used for the dark beads, the Zambrone faience beads can be compared to Mesopotamian and Minoan faience beads. They belong to a type widespread in north-central Italy between the Middle and Late Bronze Age, and in southern Italy between the Early and Late Bronze Age. The same type of faience is found in the Aegean from the middle of the 3rd millennium BCE to the 12th century BCE.

A tough challenge in nanomaterials chemistry is the determination of the structure of multicomponent nanosystems. Dye–zeolite L composites are building blocks of hierarchically organized multifunctional materials for technological applications. Supramolecular organization inside zeolite L nanochannels, which governs electronic properties, is barely understood. This is especially true for confined close-packed dye molecules, a regime not investigated in applications yet and that might have great potential for future development in this field. Here we realize for the first time composites of zeolite L with maximally packed fluorenone molecules and elucidate their structure by integrated multitechnique analyses. By IR spectroscopy, thermogravimetric analysis, and X-ray diffraction, we establish the maximum degree of dye loading obtained (1.5 molecules per unit cell), and by modeling we reveal that at these conditions fluorenone molecules form quasi 1-D supramolecular nanoladders running along the zeolite channels. Spatial and morphological control provided by the nanoporous matrix combined with a complex blend of strong dye–zeolite and weaker dye–dye van der Waals interactions lie at the origin of this unique architecture, which is also stabilized by the hydrogen bond network of coadsorbed water molecules surrounding the dye nanoladder and penetrating between its rungs.

The thermoelastic behavior and structural evolution of a natural levyne-Ca [(Ca7.8Na2.2K1.1)S11.1Al20.0Si34.2O108·51.5H2O; R3m; a = 13.377(4) Å, c = 22.870(1) Å, V = 3544.1(3) Å3] were studied by both T-resolved synchrotron X-ray powder diffraction (SR-XRPD) between room temperature and 800 °C, and by conventional-source high-temperature single-crystal X-ray diffraction (SC-XRD). Above 230 °C, water loss and reallocation of extraframework cations induce the straining and consequent breaking of T-O-T bridges in the D6R, with resulting migration of tetrahedral cations to new tetrahedral sites. The new tetrahedra share an edge with the previously occupied tetrahedra. This phenomenon gives rise to a new topology, which coexists to about 40%, with the original one. The new framework consists of a sequence of a novel zeolitic cage (described as a 20-hedron formed by fourteen 6mR and six 4mR) and two consecutive cancrinite cages along [0001]. This topology, which is reported in the database of the hypothetical zeolite structures as 166_2_293, belongs to the ABC-6 family and can be described by the following sequence of 6-rings: ABCBCACAB, to be compared with that of levyne AABCCABBC. In the new topology the extraframework cations are distributed over 3 new sites: one at the center of the 6mR ? [0001] shared by the two cancrinite cages, one near the center of the 6mR ? [0001] at the base of the new cage, and a last one in a 6mR window of the new cage. The 8mR bidimensional channel system originally present in levyne is therefore absent in the new topology and hence molecular diffusion is likely to be partially hindered in the dehydrated form. The phase transition is not completely reversible, at least in the short term, as only partial rehydration was demonstrated

This paper reports the results of an in situ high-pressure synchrotron X-ray powder diffraction investigation on the natural zeolite boggsite [(K0.06Na0.36Sr0.01Ca7.00Mg1.20)(Al17.52Si78.62Fe0.05O192)·82.3 H2O]. The study was performed using both a (16:3:1) methanol:ethanol:water mixture (m.e.w.) as a nominally “penetrating” hydrostatic P-transmitting medium and silicon oil (s.o.) as a “non-penetrating” medium. The studied pressure ranges are: Pamb-7.6 and Pamb-5.9 GPa in m.e.w and s.o., respectively. No complete X-ray amorphization is observed up to the highest investigated pressures, and the original unit-cell parameters are almost completely recovered upon decompression in both media. The reductions of a, b, c, and V, within the pressure-ranges investigated, are 5.3, 4.2, 4.0, and 13.0% in s.o. and 4.1, 4.1, 3.8, and 11.5% in m.e.w. The Rietveld structural refinements of the powder patterns of the experiments in m.e.w. converged successfully up to 3.6 GPa and demonstrated the penetration of 13 additional water molecules between 0.3 and 2.9 GPa. This over-hydration occurs without any unit-cell volume expansion and can be explained by the fact that no new extraframework sites arise during compression and that water penetration is the only factor to increase the occupancy of already existing sites. Boggsite compressibility is higher in s.o. than in m.e.w. In particular, compressibility in m.e.w. is lower below 3 GPa, whereas above this pressure, the P-V trend becomes similar in the two media. This can be ascribed to the fact that, during water molecule penetration (0.3 < P < 3 GPa), the effect of the P-transmitting medium is directed to compress the system as well as to penetrate the channels.

The HP behavior of the natural zeolite yugawaralite and of the synthetic zeolite Na-A was studied by in situ synchrotron X-ray powder diffraction, using a non-penetrating P-transmitting medium. The unit-cell parameters of yugawaralite were refined up to the pressure of 10 GPa, at which reductions were found of about 7, 2.4, 7, 1.3, and 15% for a, b, c, β, and V, respectively. Contractions of 6.5 and 18.4% were found for a and V, respectively, for zeolite Na-A in the range 10-4to 6.8 GPa. Diffraction patterns collected during decompression show that the effects induced by high pressure on both samples are almost completely reversible. These results are compared with those obtained under similar experimental conditions for other natural zeolites, with the aim of rationalizing the deformation mechanisms of these porous materials and comparing their flexibility under high-pressure and high-temperature conditions.

The HP behavior of the natural zeolite yugawaralite and of the synthetic zeolite Na-A was studied by in situ synchrotron X-ray powder diffraction, using a non-penetrating P-transmitting medium. The unit-cell parameters of yugawaralite were refined up to the pressure of 10 GPa, at which reductions were found of about 7, 2.4, 7, 1.3, and 15% for a, b, c, β, and V, respectively. Contractions of 6.5 and 18.4% were found for a and V, respectively, for zeolite Na-A in the range 10-4to 6.8 GPa. Diffraction patterns collected during decompression show that the effects induced by high pressure on both samples are almost completely reversible. These results are compared with those obtained under similar experimental conditions for other natural zeolites, with the aim of rationalizing the deformation mechanisms of these porous materials and comparing their flexibility under high-pressure and high-temperature conditions.