Complex Pore Structure of Mesoporous Zeolites: Unambiguous TEM Imaging Using Platinum Tracking

The article proposes a new way for visualization of mesopores and quantitative evaluation of the pore structure in zeolite crystals. The approach is based on platinum tracking inside the zeolite material after its incorporation from a gaseous precursor using an electron beam prior to preparing a TEM specimen by the focused ion beam technique. The pores in mesoporous silica and purely microporous zeolite Y were visualized in TEM images in a demonstration of the capabilities of the approach. Finally, platinum tracking was used for studying the pore structure of zeolite Y (CBV 720) containing mesopores both inside the crystal and those emerging at its surface, which were unambiguously distinguished from each other. The obtained sizes of the mesopores and the calculated material porosity are in good agreement with the results obtained by the low-temperature argon sorption isotherms method.     

Synthesis of Micro-Mesoporous Ti-MOR/Silica Composite Spheres in Oil-in-Water Microemulsion System

The hierarchically structured micro-mesoporous spheres(MMS) composed of mesoporous silica and Ti-containing mordenite (Ti-MOR) zeolite were self-assembled in an oil-in-water microemulsion system containing tetrabutyl orthosilicate as silica source, cetyltrimethylammonium bromide as template and aluminum sulfate as additive. The composite materials possessed the connatural microporosity of zeolite together with the disordered mesopores(5.41 nm) in silica part. With a special focus on the importance of aluminum sulfate additive, a possible formation mechanism has been proposed, in which double electrostatic interactions played the crucial role of mediating the mesosilica species and zeolite crystals. The obtained MMS materials, with a tunable particle dimension(250-720 μm) and a changeable content of active component Ti-MOR(44%-70%), showed enhanced catalytic activity and lifetime in the liquid-phase ammoximation of cyclohexanone in comparison to the parent Ti-MOR powder.     

Sulphate resistance and passivation ability of the mortar made from pozzolan cement with zeolite

Sulphate resistance and passivation ability of the mortars made from pozzolan cement of CEM IV/A (P) type according to European Standard EN 197-1 (zeolite blended cement with 60.82 mass% of PC clinker, 35.09 mass% of zeolite and 4.09 mass% of gypsum abbreviated as ZBC) and ordinary Portland cement (abbreviated as PC) are introduced. Resistance tests were performed in water and 5% sodium sulphate solution (both 20°C) for 720 days. The increased sulphate resistance of pozzolan cement relative to that of PC was found. The key quantitative insight into the hydrate phase behaviour is given by thermal analysis. This is due to pozzolanic reaction of zeolite with PC resulting in reduction of the formed Ca(OH)₂ opposite to the reference PC. Ability of pozzolan cements with 15 to 50 mass% of zeolite to protect steel against corrosion was verified in 20°C/85% RH-wet air within 180-day cure. Steel was not corroded in the mortars made with pozzolan cement containing up to 35 mass% of zeolite. Pozzolan cement of CEM IV/A (P) type containing 35 mass% of zeolite is a suitable cementitious material for concrete structures exposed to sulphate attack. Steel is protected against corrosion by this pozzolan cement in the same measure as the reference PC.     

Metabolic responses of BV-2 cells to puerarin on its polarization using ultra-performance liquid chromatography–mass spectrometry

Microglia are the primary immune cells in the central nervous system with functional plasticity. They can be activated into M1 and M2 phenotypes when neuroinflammation-related diseases occur. M1 phenotype cells produce pro-inflammatory mediators that cause neuroinflammation and the M2 phenotype can secrete anti-inflammatory cytokines that protect neurons from damage. Therefore, inhibiting the M1 phenotype while stimulating the M2 phenotype has been suggested as a potential therapeutic approach for treating neuroinflammation-related diseases. Puerarin has been demonstrated to exert anti-inflammatory and neuroprotective effects. However, the role of puerarin in regulating microglia polarization and its reaction mechanism has not been fully elucidated. In this paper, a metabolomics approach with ultra-performance liquid chromatography–mass spectrometry was performed to investigate the metabolic changes of BV-2 cells in different phenotypes and test the effects of puerarin on polarization. Thirty-nine metabolites were identified as the biomarkers related to the polarization of BV-2 cells and puerarin intervention reverted the content of most of the biomarkers. Our study demonstrated that puerarin could play a key role in M1/M2 polarization of BV-2 cells from a perspective of metabolomics, and it could regulate the balance between promotion and suppression of inflammation.     

The influence of thermal treatment on the nitrate band intensities in infra-red spectra of nitrate inclusion complexes of the zeolite 4A

The changes occurring in the included component in the course of thermal treatment of inclusion complexes of zeolite 4A with alkali nitrates were followed by IR spectroscopy and the results obtained were correlated with the data of TG analysis. An increase in temperature caused changes in the breadth and intensity of the nitrate bands (at about 1450 and 1380 cm^–1) and the appearance of a new band at about 1350 cm^–1. All the mentioned effects relate to the temperature interval starting from room temperature up to 670 K and are attributed to the increase in the thermal motion of included species in zeolite cages. The activation energy of the coordination change of the nitrate groups in the cage was calculated from the ratio of intensities of the nitrate bands at 1450 and 1350 cm^–1 and the intensity of the zeolite band at 460 cm^–1, originating from aT–O bending vibration as a function of temperature. At temperatures exceeding 720 K decomposition of included nitrate was noticed. Having this in mind, it was concluded that the changes of the band intensities were closely connected with this process.     

Celastrol inhibits production of nitric oxide and proinflammatory cytokines through MAPK signal transduction and NF-kappaB in LPS-stimulated BV-2 microglial cells

Excessive production of nitric oxide (NO) and proinflammatory cytokines from activated microglia play an important role in human neurodegenerative disorders. Here, we investigated whether celastrol, which has been used as a potent anti-inflammatory and anti-oxidative agent in Chinese medicine, attenuates excessive production of NO and proinflammatory cytokines such as TNF-alpha and IL-1betal in LPS-stimulated BV-2 cells, a mouse microglial cell line. We report here that the LPS-elicited excessive production of NO, TNF-alpha, and IL-1beta in BV-2 cells was largely inhibited in the presence of celastrol, and the attenuation of inducible iNOS and these cytokines resulted from the reduced expression of mRNAs of iNOS and these cytokines, respectively. The molecular mechanisms that underlie celastrol-mediated attenuation were the inhibition of LPS-induced phosphorylation of MAPK/ERK1/2 and the DNA binding activity of NF-kappaB in BV-2 cells. The results indicate that celastrol effectively attenuated NO and proinflammatory cytokine production via the inhibition of ERK1/2 phosphorylation and NF-kappaB activation in LPS-activated microglia. Thus, celastrol may be an effective therapeutic candidate for use in the treatment of neurodegenerative human brain disorders.     

分子筛表面酸性对微波固相法制备ZnCl2/Y催化剂的影响

 采用XRD和原子吸收光谱法研究了微波作用下分子筛表面酸性对ZnCl2与Y分子筛固态相互作用的影响．结果表明，微波辐射可显著促进ZnCl2在分子筛表面分散，其分散阈值与分子筛表面酸性有关．随着分子筛表面酸量和酸强度增加，ZnCl2在分子筛表面的最大分散量减少，分散的ZnCl2与Y分子筛的固态离子交换量也减少；NaY型分子筛比HY分子筛更容易发生固态离子交换反应．考察了微波固相法制备的ZnCl2／HY催化剂在苯甲醚与乙酰氯酰化反应中的催化性能．结果表明，在分子筛表面分散的ZnCl2具有更高的催化活性及对甲氧基苯乙酮选择性．     

一种新型共生沸石(T-L)的合成与表征

在Na₂O-K₂O-Al₂O₃-SiO₂-H₂O体系中水热合成了一种新型的共生沸石, 它由L型沸石生长在T型沸石的一端而形成, 称之为T-L型沸石. 通过XRD, SEM, TEM, EDX, IR等手段对其进行了初步的表征. SEM相片表明这种沸石具有特殊的铆钉状外形; 在TEM相片上可以清楚地看到L型沸石的大孔道, 此孔道与L型沸石的表面垂直. 通过EDX的数据计算发现共生沸石的两相有不同的骨架硅铝比: T型沸石部分Si/Al＝3.71, L型沸石部分Si/Al＝3.41. 在该样品中B酸大于L酸.     

微波法研制催化降解亚硝胺的ZrO2/NaY沸石新材料

通过微波辐射能将ZrO2直接分散在NaY沸石上,调变沸石的表面酸碱性质并制成降解亚硝胺的催化新材料;其分散阈值约为10%。ZrO2/NaY对于吡咯烷亚硝胺降解的催化能力优于ZrO2和NaY沸石,在空气中降解还能显著抑制生成NOx。     

磁性4A沸石制备及其对水中氯乙酸吸附

以工业级水玻璃、NaAlO2、NaOH和去离子水为原料,采用水热法先合成4A分子筛,然后在二价和三价铁离子混合溶液中用氨水调节负载铁的氧化物及真空干燥等步骤,制得了一系列磁化率不同的磁性分子筛,并对其进行了XRD、SEM、IR及TG等表征分析.结果表明,合成磁性4A沸石晶形完整,表面负载的四氧化三铁分布均匀,磁化率随所负载四氧化三铁量的增加而增大,粒度比纯4A沸石大.磁性4A沸石对钙、镁、铅和氯乙酸的吸附性能与纯4A沸石相当,利用磁性4A沸石可以方便地用磁场分离的特性,其粉末状产品不用成型就可以直接在溶剂或溶液中使用.     

The Effects of Berry Extracts on Oxidative Stress in Cultured Cardiomyocytes and Microglial Cells: A Potential Cardioprotective and Neuroprotective Mechanism

Oxidative stress is a key underlying factor in cognitive decline and atherosclerosis. Oxidative stress occurs at the cellular level with an imbalance between reactive oxygen species and reactive nitrogen species and a deficiency in antioxidants. Mounting evidence suggests that berry flavonoids may promote cellular health by exerting antioxidant properties. Black currant and various berry extracts were tested in microglia (BV-2) and cardiomyocyte (HL-1) cell lines to study their biological effects. The principal ingredients in black currant and cranberry extract–delphinidin 3-rutinoside (D3R) and cyanidin 3-glucoside (C3G), were also assessed. A menadione-induced oxidative stressor was used, and its output was quantified to detect oxidative stress (CellROX^TM). Black currant extract had similar antioxidant effects as N-acetylcysteine (NAC) in HL-1 cells with regard to cellular protection, whereas cranberry extract was ineffective. In contrast, cranberry extract was comparable in effectiveness to black currant extract in BV-2 cells. D3R and C3G also reduced oxidative stress similarly to whole berry extracts, which indicates that these ingredients may confer the antioxidant effects of berries. Black currant and cranberry extracts inhibit oxidative stress in microglial and cardiomyocyte cell lines. Black currant extract was more effective in reducing oxidative stress in the HL-1 cells, whereas cranberry extract was comparable in reducing oxidative stress in the BV-2 cells. The results suggest that berry flavonoids exert neuro- and cardioprotective effects.     

Chemical Structure and In Vitro Antitumor Activity of Rhamnolipids from Pseudomonas aeruginosa BN10

A newly isolated indigenous strain BN10 identified as Pseudomonas aeruginosa was found to produce glycolipid (i.e., rhamnolipid-type) biosurfactants. Two representative rhamnolipidic fractions, RL-1 and RL-2, were separated on silica gel columns and their chemical structure was elucidated by a combination of nuclear magnetic resonance and mass spectroscopy. Subsequently, their cytotoxic effect on cancer cell lines HL-60, BV-173, SKW-3, and JMSU-1 was investigated. RL-1 was superior in terms of potency, causing 50 % inhibition of cellular viability at lower concentrations, as compared to RL-2. Furthermore, the results from fluorescent staining analysis demonstrated that RL-1 inhibited proliferation of BV-173 pre-B human leukemia cells by induction of apoptotic cell death. These findings suggest that RL-1 could be of potential for application in biomedicine as a new and promising therapeutic agent.     

含有乙醚的无胺无氟反应物体系中高硅丝光沸石的合成

本文研究含有乙醚的Na2O-Al2O3-SiO2-H2O反应物中高硅丝光沸石在413-453K下的水热合成。乙醚的存在能有效促进丝光沸石的结晶过程,且有助于提高产物结晶度和硅铝比。反应物胶体中硅铝比与碱度对产物的生成有关键作用。合成原料使用不同铝源,体系结晶规律相近,但产物的形貌和硅铝比有差异。在优化的反应条件下合成的高硅丝光沸石硅铝比达30左右。低温氮吸附与27Al魔角旋转核磁谱表征证实该沸石骨架结构完美,孔道开放畅通,其水热稳定性优于低硅丝光沸石。     

微波辐射促进ZnCl_2与Y分子筛固相反应的研究

采用XRD、IR和原子吸收光谱等手段对微波固相法制备的ZnCl2／Y催化剂进行了表征·微波辐射促进了ZnCl2在分子筛表面分散和固态离子交换，分散的ZnCl2可与分子筛表面氧原子发生较强的配住键合作用．当ZnCl2的负载量达到37．5％时，ZnCl2仍可完全分散于NaY分子筛表面，此时的固态离子交换度为84％．随着分子筛表面酸菌和区强度的增加，ZnCl2与分子筛的固态离子交换量减少．     

微波辐射促进ZnCl2与Y分子筛固相反应的研究

ZnCl2/Y catalysts prepared by solid-state reaction of anhydrous ZnCl2 and Y zeolites under microwave irradiation were characterized by XRD, IR and AAS. ZnCl2 was intercalated in Y zeolites and dispersed on the surface of Y zeolite, part of ZnCl2 dispersed could result in solid-state ion exchange with Y. The amount of dispersion and solid-state ion exchange were related to ZnCl2 loading and the surface acid property of the zeolite. When ZnCl2 loading was 37.5% (mass fraction) in NaY zeolite, ZnCl2 was still completely dispersed on the surf are of zeolite and the degree of solid- state ion exchang was 84%. The appearance of new band at 890 cm-l in the framework IR spectra of ZnCl2/NaY sample was due to the dispersed ZnCl2 coordinating strongly with oxygen of NaY surface. With the increasing of the number of arid centers and the acid strength of the surface of Y zeolite the amount of solid-state ion exchange decreased.     

天然CXN沸石分子筛水热稳定性研究 II. 水蒸汽处理温度对铵型沸石物化性质的影响

在前文研究天然Stilbite沸石(CXN沸石)水热稳定性影响因素的基础上, 以27Al与29Si MAS NMR, NH3-TPD和低温氮吸附等详细研究了铵型CXN沸石骨架铝配位状态和硅配位状态, 表面酸性与孔性质等与水蒸汽处理温度的关系. 随温度升高, 沸石骨架硅铝比逐渐提高, 并伴随硅羟基缺陷增多. 经750 ℃水蒸汽处理3 h后沸石骨架硅铝比可达到21.3. 沸石总酸量随水蒸汽处理温度的提高而降低, 沸石骨架铝脱除造成沸石孔道部分被堵塞, 但同时形成有利于分子扩散的介孔.     

α-Fe2O3在Y沸石上的分散

用草酸高铁铵浸渍NaY沸石, 并在高温下焙烧, 得到α-Fe_2O_3/NaY沸石体系。经XRD相定量外推法测定, α-Fe_2O_3在NaY沸石上的最大分散量为0.060 gα-Fe_2O_3/gNaY, 仅占α-Fe_2O_3在沸石表面密置单层量的5.5%。首次尝试用正电子寿命谱方法测定α-Fe_2O_3在沸石表面的最大分散量, 所得结果与XRD方法完全吻合。由程序升温还原方法发现沸石上α-Fe_2O_3的还原分两步进行, α-Fe_2O_3先还原成Fe_3O_4, 然后再还原成金属。α-Fe_2O_3分散相与沸石之间的强相互作用, 使这两个还原反应受到阻抑。     

In situ evaluation of defect size distribution for supported zeolite membranes

The permporometry measurements are performed with respect to a series of zeolite membranes with different defect sizes, which can be further applied for in situ measurement of the defect size distribution in zeolite membranes. Gas permeation experiments are conducted for CO₂/N₂ gas mixture to test the separation performance of the studied zeolite membranes. By taking into account the “t-layer” on defect walls, a mathematical model and the corresponding procedure are developed so that the defect size distribution in zeolite membranes can be calculated by using the results of permporometry measurements. The defect size distribution and the maximal defect size show a good correlation with the separation performance of CO₂/N₂ gas mixture for zeolite membranes. It is demonstrated that the separation performance of zeolite membranes is mainly determined by large defects. It has been shown that the permporometry-based methodology proposed in this contribution is an effective way for the quality evaluation of zeolite membranes.     

Adsorptive desulfurization of propylene derived from bio-ethanol

We studied adsorption characteristics of a series of LTA zeolite as an adsorbent for desulfurization of propylene, that was produced from bioethanol by ethanol-to-olefin (ETO) conversion. A breakthrough curve (BTC) for adsorption of methanethiol, as one of the sulfur impurities of propylene produced from bioethanol, in the presence of propylene was measured using a fixed-bed column packed with the LTA zeolite. The BTC revealed that the effect of the competitive adsorption of propylene on the LTA zeolite strongly depended on a cation species exchanged in the micropores of the zeolite. Among the cation species examined in this study, bivalent cation of zinc (Zn²⁺) was proved to be the most effective one to increase the amount of methanethiol adsorbed on the LTA zeolite under the presence of propylene. The specific interaction of methanethiol with the LTA zeolite exchanged with Zn²⁺ was confirmed by the measurement of a temperature-programmed desorption (TPD) spectrum of methanethiol.