CO2-Induced Gate-Opening Adsorption on a Chabazite/Phillipsite Composite Zeolite Transformed from a Faujasite Zeolite Using Organic Structure-Directing Agent-Free Steam-Assisted Conversion

Organic structure-directing agent-free steam-assisted conversion and Cs+ ion exchange were used to transform the faujasite (FAU)-type zeolite to the Cs+-type chabazite/phillipsite (CHA/PHI) composite zeolite. Compared with the pure PHI-type zeolite, the Cs+-type CHA/PHI zeolite showed gate-opening CO2 adsorption behavior and good thermal stability. In situ powder X-ray diffraction (PXRD) of the CO2 adsorption was measured to elucidate the mechanism for the gate-opening adsorption on the CHA/PHI zeolite. The Na+-type CHA/PHI zeolite did not show such adsorption behavior, and the PXRD pattern of the Na+-type CHA/PHI zeolite did not change with increasing CO2 partial pressure, which suggests that this unique adsorption behavior was caused by the PHI framework transition or Cs+ ions moving in both the CHA and PHI frameworks. Furthermore, in situ Fourier-transform infrared spectra of CO2 adsorption and CO2 breakthrough measurement on the Cs+-type CHA/PHI zeolite suggest that the CHA and PHI frameworks in the CHA/PHI zeolite shared eight-membered-ring windows and that CO2 molecules could easily diffuse from a CHA cage to a PHI framework. The ideal adsorbed solution theory was used to calculate the CO2/N2 separation selectivity for the Cs+-type CHA/PHI zeolite. At 298 and 318 K, the Cs+-type CHA/PHI composite zeolite showed a high CO2/N2 separation coefficient of >10,000 compared with other zeolites with high CO2 adsorption capacity. Furthermore, the CO2 working capacity was calculated for the Cs+-type CHA/PHI zeolite in both the pressure- and temperature-swing processes, and the results showed that the CHA/PHI composite zeolite could selectively separate CO2 from the CO2/N2 gas mixtures released from power generation plants operating using these processes.

Design of Zr- and Al-Doped *BEA-Type Zeolite to Boost LDPE Cracking

Nowadays, the increase in plastic waste is causing serious environmental problems. Catalytic cracking has been considered a promising candidate to solve these problems. Catalytic cracking has emerged as an attractive process that can produce valuable products from plastic wastes. Solid acid catalysts such as zeolites decompose the plastic waste at a lower temperature. The lower decomposition temperature may be desirable for practical use. Herein, we synthesized both Zr- and Al-incorporated Beta zeolite using amorphous ZrO₂-SiO₂. The optimized Zr content in the dry gel allowed the enhancement of Lewis acidity without a significant loss of Brønsted acidity. The enhancement of Lewis acidity was mainly due to Zr species incorporated into the zeolite framework. Thanks to the enhanced Lewis acidity without any significant loss of Brønsted acidity, higher polymer decomposition efficiency was achieved than a conventional Beta zeolite.

High coke deposition resistance by Cr loading on zeolite defects: reduced regeneration in cracking reactions

A Cr-loaded zeolite cannot be considerably deactivated by coke deposition and can be reused for LDPE cracking without regeneration. The Cr species interact with hydroxyl groups derived from structural defects...

A case of lung adenocarcinoma complicated by pulmonary talcosis occurring in a patient employed in the confectionery industry

A 73-year-old Japanese man, who worked at a confectionery company for more than 20 years, was diagnosed with a 28 mm nodular lesion in the superior lobe of the right lung by whole-body computed tomography examination. A biopsy revealed the presence of adenocarcinoma. With a diagnosis of a primary lung cancer, a right upper lobectomy was performed. A nodular lesion, 25 × 23 mm in size, was observed in the upper right lobe lung field, and was diagnosed histopathologically as a papillary adenocarcinoma. In addition, fibrous scars in the central part of the tumor showed numerous Langhans and/or foreign body giant cells, and histiocytic cells that had phagocytized numerous small transparent crystals, together with coal powder deposition. The extracted crystals were observed with a scanning electron microscope, and although plate-like structures were observed, ferruginous bodies suggestive of asbestos were not found. The crystals were demonstrated to be talc by powder X-ray diffraction. Herein, we investigated a case of lung adenocarcinoma in a patient with talcosis, with discussions based on a literature search. This collision of talcosis and lung adenocarcinoma adds to an increasing body of knowledge on an apparent association between talc and cancer cases.

Dehydrogenation of propane over high silica *BEA type gallosilicate (Ga-Beta)

Propane was found to be dehydrogenated over the Brønsted acid sites derived from incorporated Ga in the 12-membered large micropores of a *BEA-type structure.

High Water Tolerance of a Core-Shell-Structured Zeolite for CO2 Adsorptive Separation under Wet Conditions

Dehumidification in CO₂ adsorptive separation processes is an important issue, owing to its high energy consumption. However, available adsorbents such as low-silica zeolites show a significant decrease in CO₂ adsorption capacity when water vapor is present. A core-shell-structured MFI-type zeolite with a hydrophilic ZSM-5 coated with a hydrophobic silicalite-1 shell layer was applied in CO₂ adsorptive separation under wet conditions. This hybrid material demonstrated remarkably high water tolerance with stable CO₂ adsorption performance without additional thermal treatment for regeneration, whereas a significant decrease in the CO₂ adsorption amount because of water vapor was observed on the parent ZSM-5. The core-shell structure of zeolites with high pore volumes, such as LTA or CHA, could also be suitable candidates for high CO₂ adsorption capacity and high water tolerance for practical applications.

Synthesis and crystal structures of a novel layered silicate SSA-1 and its microporous derivatives by topotactic transformation

The synthesis of a novel layered silicate SSA-1 (SSA: silicate synthesized with a quaternary amine) was achieved in the SiO₂-H₂O-TEAOH (TEAOH: tetraethylammonium hydroxide - as an organic structural directing agent) system. The crystal structure of SSA-1 involved two silicate layers composed of bre [10T]-type CBU (Composite Building Unit) and TEAOH in interlayers. The topotactic transformation of SSA-1 by calcination was examined, resulting in a porous material (PML-1: porous material transformed from a layered silicate) with a 108 m² g^-1 BET surface area and 0.035 cm³ g^-1 pore volume. PML-1 is a siliceous microporous material with silanols in the framework and possesses unique properties, such as hydrophilicity, in spite of all its silica composition. The most reasonable crystal structure of PML-1 was successfully determined on the basis of the crystal structure of SSA-1 by a combination of manual modelling, PXRD pattern simulation, DFT optimization and Rietveld analysis. Additionally, an interlayer expanded siliceous zeolite SSA-1 (IEZ-SSA-1) was also successfully prepared by silylation using trichloro(methyl)silane under acidic conditions. IEZ-SSA-1 showed hydrophilicity or hydrophobicity properties by changing the functional group of the pillar part in the interlayer. Additionally, IEZ-SSA-1 showed a large gas adsorption property (537 m² g^-1 and 0.21 cm³ g^-1).

Design of Microporous Material HUS-10 with Tunable Hydrophilicity, Molecular Sieving, and CO2 Adsorption Ability Derived from Interlayer Silylation of Layered Silicate HUS-2

The attractive properties of zeolites, which make them suitable for numerous applications for the energy and chemical industries and for life sciences, are derived from their crystalline framework structures. Herein, we describe the rational synthesis of a microporous material, HUS-10, utilizing a layered silicate precursor, HUS-2, as a structural building unit. For the ordered micropores to be formed, interlayer pillars that supported the original silicate layer of HUS-2 were immobilized through the interlayer silylation of silanol groups with trichloromethylsilane and a subsequent dehydration-condensation reaction of the hydroxyl groups on the preintroduced tetrahedral units. An actual molecular sieving ability, enabling the adsorption of molecules smaller than ethane, was confirmed in the ordered micropores of HUS-10. The hydrophilic adsorption could also be controlled by changing the number of methyl and hydroxyl groups in the immobilized interlayer pillars. In addition, when the adsorption behaviors of CO2, CH4, and N2 on HUS-10 were compared to those on siliceous MFI and CDO zeolites with approximately the same pore diameter, the CO2 adsorption capacity of HUS-10 was comparable. Conversely, because of the adsorption inhibition of CH4 and N2, HUS-10 exhibited larger CO2/CH4 and CO2/N2 adsorption ratios relative to those of MFI and CDO zeolites. These results reveal that the unique microporous framework structure presented by the rational structural design using the layered silicate precursor HUS-2 has the potential to separate CO2 from gas mixtures.

In situ solvothermal growth of highly oriented Zr-based metal organic framework UiO-66 film with monocrystalline layer

A highly oriented UiO-66 film, with a monocrystalline layer, was successfully prepared by the solvothermal method.

Diabetes mellitus aggravates hemorrhagic transformation after ischemic stroke via mitochondrial defects leading to endothelial apoptosis

Diabetes is a crucial risk factor for stroke and is associated with increased frequency and poor prognosis. Although endothelial dysfunction is a known contributor of stroke, the underlying mechanisms have not been elucidated. The aim of this study was to elucidate the mechanism by which chronic hyperglycemia may contribute to the worsened prognosis following stroke, especially focusing on mitochondrial alterations. We examined the effect of hyperglycemia on hemorrhagic transformation at 24 hours after middle cerebral artery occlusion (MCAO) in streptozotocin (STZ) -induced diabetic mice. We also examined the effects of high-glucose exposure for 6 days on cell death, mitochondrial functions and morphology in human brain microvascular endothelial cells (HBMVECs) or human endothelial cells derived from induced pluripotent stem cells (iCell endothelial cells). Hyperglycemia aggravated hemorrhagic transformation, but not infarction following stroke. High-glucose exposure increased apoptosis, capase-3 activity, and release of apoptosis inducing factor (AIF) and cytochrome c in HBMVECs as well as affected mitochondrial functions (decreased cell proliferation, ATP contents, mitochondrial membrane potential, and increased matrix metalloproteinase (MMP)-9 activity, but not reactive oxygen species production). Furthermore, morphological aberration of mitochondria was observed in diabetic cells (a great deal of fragmentation, vacuolation, and cristae disruption). A similar phenomena were seen also in iCell endothelial cells. In conclusion, chronic hyperglycemia aggravated hemorrhagic transformation after stroke through mitochondrial dysfunction and morphological alteration, partially via MMP-9 activation, leading to caspase-dependent apoptosis of endothelial cells of diabetic mice. Mitochondria-targeting therapy may be a clinically innovative therapeutic strategy for diabetic complications in the future.

Synthesis and crystal structure of a layered silicate HUS-1 with a halved sodalite-cage topology

A new layered silicate, HUS-1, was synthesized by hydrothermal synthesis using decomposed FAU- and *BEA-type zeolites as nanosized silica parts. Structural analyses by X-ray powder diffractometry and solid-state magic-angle-spinning (MAS) NMR spectroscopy revealed that HUS-1 has a layered structure containing a silicate layer per unit cell along a stacking direction. Its framework topology is similar to that of SOD-type zeolites and consists of a halved sodalite cage, which includes four- and six-membered Si rings. Structure refinement by the Rietveld method showed that tetramethylammonium (TMA) ions used as a structure-directing agent (SDA) were incorporated into the interlayer. The four methyl groups of the TMA molecule were located orderly in a hemispherical cage in the silicate layer, which suggests restraint of molecular motion. The interlayer distance is estimated at about 0.15 nm, which is unusually short in comparison with that in other layered silicates (e.g., β-HLS or RUB-15) with similar framework topologies. The presence of hydrogen bonding between adjacent terminal O atoms was clearly revealed by the (1)H MAS NMR spectroscopy and by electron-density distribution obtained by the maximum entropy method.

Understanding of the formation of mesostructured alkylammonium-alkaline earth metal phosphates composed of ionic frameworks

A lamellar material composed of alternating layers of magnesium phosphate sheets and n-hexadecylammonium (n-C16H33NH3+) ions was synthesized by the reaction between magnesium acetate tetrahydrate and phosphoric acid. The chemical formula of the composite material was determined to be (n-C16H33NH3+)Mg2+(HPO4(2-))(H2PO4-) by ICP, TG, and 31P MAS NMR measurements. The lamellar composite was obtained under basic conditions adjusted with tetramethylammonium (TMAOH) and tetraethylammonium hydroxides (TEAOH), while ammonium ions did not act as an alkali source useful for obtaining the composite material. The formation of crystalline byproducts such as hydrated newberyite (MgHPO4.3H2O) and ammonium-type struvite (MgNH4PO4. 6H2O) was suppressed by using the EtOH/H2O mixed solution and by adding TMAOH and TEAOH to adjust the synthetic condition, respectively. Including the data on calcium, barium and strontium phosphates, we can totally understand the formation of the mesostructured materials composed of ionic frameworks in the presence of n-alkylamines in detail. It is quite important to suppress the formation of crystalline alkaline earth metal phosphates and control the solubilities of reactants and products for synthesizing pure mesostructured materials with ionically crosslinked frameworks.

Templating route for mesostructured calcium phosphates with carboxylic acid- and amine-type surfactants

Mesostructured calcium phosphates constructed by ionic frameworks were synthesized using carboxylic acid- and amine-type surfactants in mixed solvent systems of ethanol and water. A lamellar mesostructured calcium phosphate was prepared using palmitic acid as an anionic surfactant, as in the case using n-alkylamines. A wormhole-like mesostructured calcium phosphate can be obtained using dicarboxyl N-lauroyl- l-glutamic acid, whose headgroup is larger than that of palmitic acid. Similar mesostructured product was obtained using 4-dodecyldiethylenetriamine with a large headgroup containing two primary amine groups. Interactions of carboxyl and primary amino groups in the surfactant molecules with inorganic species are quite important for the formation of mesostructured calcium phosphates. The Ca/P molar ratio of mesostructured calcium phosphates was strongly affected by the molecular structure of surfactants containing carboxyl and primary amino groups. Ca-rich materials can be obtained using carboxylic acid-type surfactants (Ca/P approximately 1.7) rather than amine-type surfactants (Ca/P approximately 1.0).

Nanoacorns: Anisotropically Phase-Segregated CoPd Sulfide Nanoparticles

The anisotropically phase-segregated CoPd sulfide nanoparticles, named "CoPd nanoacorns", were spontaneously generated by reducing the corresponding metal precursors with 1,2-hexadecanediol in the presence of various alkanethiols. The CoPd nanoacorn consisting of crystalline Co9S8 and amorphous PdSx phases with the Co9S8 (001) plane at their interface was found to spontaneously form through the anisotropic growth of the Co9S8 phase after the generation of PdSx nanoparticles.

Formation of low-symmetric 2D superlattices of gold nanoparticles through surface modification by acid-base interaction

In the present work, a novel method was developed for the fabrication of 2D superlattices with different symmetries. Same-surface amino-functionalized Au nanoparticles as building blocks were self-assembled to form different 2D superlattices using surface modification with organic acids. The 2D superlattices of quasi-honeycomb and square structures were obtained by neutralizing amino-functionalized Au nanoparticles with 1,3,5-tribenzenecarboxylic acid and acetic acid, respectively. These results strongly suggest that the different types of 2D or 3D superlattices can be constructed by simple addition of proper acid to nanoparticles functionalized with amino groups. This method will allow us to obtain various desired metal superlattices without fully synthesizing the ligands.