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https://www.readbyqxmd.com/read/28218678/adsorptive-desulfurization-of-model-gasoline-by-using-different-zn-sources-exchanged-nay-zeolites
#1
Jingwei Rui, Fei Liu, Rijie Wang, Yanfei Lu, Xiaoxia Yang
A series of Zn-modified NaY zeolites were prepared by the liquid-phase ion-exchange method with different Zn sources, including Zn(NO₃)₂, Zn(Ac)₂ and ZnSO₄. The samples were tested as adsorbents for removing an organic sulfur compound from a model gasoline fuel containing 1000 ppmw sulfur. Zn(Ac)₂-Y exhibited the best performance for the desulfurization of gasoline at ambient conditions. Combined with the adsorbents' characterization results, the higher adsorption capacity of Zn(Ac)₂-Y is associated with a higher ion-exchange degree...
February 17, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28218532/csbxge6-xo12-x-1-a-zeolite-sodalite-type-borogermanate-with-a-high-ge-b-ratio-by-partial-boron-substitution
#2
Rui Pan, Jian-Wen Cheng, Bai-Feng Yang, Guo-Yu Yang
The partial replacement of Ge atoms in tetrahedral positions by a small number of B atoms leads to a new microporous borogermanate, CsBxGe6-xO12 (x = 1), under solvothermal conditions. Its framework shows the highest atomic ratios of Ge/B in reported borogermanates and leads to a new type of zeolite sodalite-type net.
February 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28217845/probing-zeolite-crystal-architecture-and-structural-imperfections-using-differently-sized-fluorescent-organic-probe-molecules
#3
Bert Marc Weckhuysen, Frank Hendriks, Joel Schmidt, Jeroen Rombouts, Koen Lammertsma, Pieter Bruijnincx
A micro-spectroscopic method has been developed to probe the accessibility of zeolite crystals using a series of fluorescent 4-(4-diethylaminostyryl)-1-methylpyridinium iodide (DAMPI) probes of increasing molecular size. Staining of large zeolite crystals with MFI topology and subsequent mapping of the resulting fluorescence using confocal fluorescence microscopy reveal differences in structural integrity: the 90° intergrowth sections of MFI crystals are prone to develop structural imperfections, which act as entrance routes for the probes into the zeolite crystal...
February 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28215083/development-of-a-zeolite-filter-for-removing-polycyclic-aromatic-hydrocarbons-from-smoke-and-smoked-ingredients-whilst-retaining-the-smoky-flavor
#4
Jane K Parker, Stella Lignou, Kenneth Shankland, Phillipa Kurwie, Huw D Griffiths, David A Baines
The popularity of smoked foodstuffs such as sauces, marinades and rubs is on the rise. However, during the traditional smoking process, in addition to the desirable smoky aroma compounds, harmful polycyclic aromatic hydrocarbons (PAHs) are also generated. In this work, a selective filter was developed which reduces PAH concentrations in a smoke by up to 90%, whilst maintaining a desirable smoky flavor. Preliminary studies using a cocktail of 12 PAHs stirred with a zeolite showed the potential for this zeolite to selectively remove PAHs from a simple solution...
February 18, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28213257/a-zeolitic-imidazolate-framework-based-nanoporous-carbon-as-a-novel-fiber-coating-for-solid-phase-microextraction-of-pyrethroid-pesticides
#5
Shuaihua Zhang, Qian Yang, Xiumin Yang, Wenchang Wang, Zhi Li, Lihong Zhang, Chun Wang, Zhi Wang
A high-surface-area nanoporous carbon (NPC) has been successfully synthesized by using the metal-organic framework ZIF-90 as both the template and precursor together with furfuryl alcohol as a secondary carbon source. The prepared ZIF-90 templated NPC (ZIF-90-NPC) was then coated onto a stainless steel wire by a simple physical adhesion approach to prepare solid-phase microextraction (SPME) fiber. By coupling the ZIF-90-NPC coated fiber-based SPME with gas chromatography-microelectron capture detection (GC-μECD), the developed method gave a large enhancement factor (984-2869), low limit of detection (0...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28212030/revisiting-silicalite-1-nucleation-in-clear-solution-by-electrochemical-impedance-spectroscopy
#6
Gert Brabants, Maxim Hubin, Erwin Konrad Reichel, Bernhard Jakoby, Eric Breynaert, Francis Taulelle, Johan A Martens, Christine E A Kirschhock
EIS was used to detect and investigate nucleation in silicalite-1 clear solutions. Whereas zeolite nucleation was previously assumed to be a step event, inducing a sharp discontinuity around a Si/OH ratio of 1, complex bulk conductivity measurements at elevated temperatures reveal a gradual decay of the conductivity with increased silicon concentrations. Inverse Laplace transformation of the complex conductivity allows to observe the chemical exchange phenomena governing nano-aggregate formation. At low temperatures, the fast exchange between dissociated ions and ion pairs leads to a gradual decay of the conductivity with increasing silicon content...
February 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28208658/synthesis-and-transport-properties-of-novel-mof-pim-1-mof-sandwich-membranes-for-gas-separation
#7
Alessio Fuoco, Muhanned R Khdhayyer, Martin P Attfield, Elisa Esposito, Johannes C Jansen, Peter M Budd
Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes...
February 11, 2017: Membranes
https://www.readbyqxmd.com/read/28207233/nanoscale-pdo-catalyst-functionalized-co3o4-hollow-nanocages-using-mof-templates-for-selective-detection-of-acetone-molecules-in-exhaled-breath
#8
Won-Tae Koo, Sunmoon Yu, Seon-Jin Choi, Ji-Soo Jang, Jun Young Cheong, Il-Doo Kim
The increase of surface area and the functionalization of catalyst are crucial to development of high-performance semiconductor metal oxide (SMO) based chemiresistive gas sensors. Herein, nanoscale catalyst loaded Co3O4 hollow nanocages (HNCs) by using metal-organic framework (MOF) templates have been developed as a new sensing platform. Nanoscale Pd nanoparticles (NPs) were easily loaded on the cavity of Co based zeolite imidazole framework (ZIF-67). The porous structure of ZIF-67 can restrict the size of Pd NPs (2-3 nm) and separate Pd NPs from each other...
February 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28199049/towards-organic-zeolites-and-inclusion-catalysts-heptazine-imide-salts-can-exchange-metal-cations-in-the-solid-state
#9
Markus Antonietti, Aleksandr Savateev, Sergey Pronkin, Marc Willinger, Dariya Dontsova
Highly crystalline potassium (heptazine imides) were prepared by the thermal condensation of substituted 1,2,4-triazoles in eutectic salt melts. These semiconducting salts are already known to be highly active photocatalysts, e.g. for the visible light driven generation of hydrogen from water. Herein, we show that within the solid state structure, potassium ions can be exchanged to other metal ions while the crystal habitus is essentially preserved.
February 15, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28197839/the-role-of-water-in-the-elastic-properties-of-aluminosilicate-zeolites-dft-investigation
#10
Ilya A Bryukhanov, Andrey A Rybakov, Alexander V Larin, Dmitry N Trubnikov, Daniel P Vercauteren
The bulk and Young moduli and heats of hydration have been calculated at the DFT level for fully optimized models of all-siliceous and cationic zeolites with and without water, and then compared to the corresponding experimental data. Upon the addition of water, the monovalent alkali ion and divalent alkaline earth ion exchanged zeolites presented opposite trends in the elastic modulus. The main contribution to the decrease in the elastic modulus of the alkali ion exchanged zeolites appeared to be a shift of cations from the framework oxygen atoms upon water addition, with the coordination number often remaining the same...
March 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28194971/ultrasensitive-assay-for-telomerase-activity-via-self-enhanced-electrochemiluminescence-ruthenium-complex-doped-metal-organic-frameworks-with-high-emission-efficiency
#11
Chengyi Xiong, Wenbin Liang, Yingning Zheng, Ying Zhuo, Yaqin Chai, Ruo Yuan
Here, an ultrasensitive "off-on" electrochemiluminescence (ECL) biosensor was proposed for the determination of telomerase activity by using self-enhanced Ruthenium- polyethylenimine (Ru-PEI) complex doped zeolitic imidazolate framework-8 (Ru-PEI@ZIF-8) with high ECL efficiency as ECL indicators and an enzyme-assisted DNA cycle amplification strategy. The Ru-PEI@ZIF-8 nanocomposites were synthesized by self-enhanced Ru-PEI complex doping during the growth of zeolitic imidazolate framework-8 (ZIF-8), which presented high ECL efficiency and excellent stability...
February 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192360/selective-fenton-like-oxidation-of-methylene-blue-on-modified-fe-zeolites-prepared-via-molecular-imprinting-technique
#12
Yuanyuan Zhang, Jiaobo Shang, Yanqun Song, Chuan Rong, Yinghui Wang, Wenyu Huang, Kefu Yu
A facile strategy to increase the selectivity of heterogeneous Fenton oxidation is investigated. The increase was reached by increasing selective adsorption of heterogeneous Fenton catalyst to a target pollutant. The heterogeneous Fenton catalyst was prepared by a two-step process. First, zeolite particles were imprinted by the target pollutant, methylene blue (MB), in their aggregations, and second, iron ions were loaded on the zeolite aggregations to form the molecule imprinted Fe-zeolites (MI-FZ) Fenton catalyst...
February 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28192359/using-numerical-simulation-of-a-one-stage-vertical-flow-wetland-to-optimize-the-depth-of-a-zeolite-layer
#13
Bernhard Pucher, Hernán Ruiz, Joëlle Paing, Florent Chazarenc, Pascal Molle, Guenter Langergraber
This simulation study investigates the treatment performance of a compact French vertical flow wetland using a zeolite layer in order to increase ammonium nitrogen removal. For the modelling exercise, the biokinetic model CW2D of the HYDRUS Wetland Module is used. The calibrated model is able to predict the effect of different depths of the zeolite layer on ammonium nitrogen removal in order to optimize the design of the system. For the model calibration, the hydraulic effluent flow rates as well as influent and effluent concentrations of chemical oxygen demand (COD) and NH4-N have been measured...
February 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28192353/removal-of-ammonium-and-heavy-metals-by-cost-effective-zeolite-synthesized-from-waste-quartz-sand-and-calcium-fluoride-sludge
#14
Qian Zhang, Bing Lin, Junming Hong, Chang-Tang Chang
This study focuses on the effectiveness of zeolite (10% CF-Z [0.5]) hydrothermally synthesized from waste quartz sand and calcium fluoride (CF) for ammonium ion and heavy metal removal. Zeolite was characterized through powder X-ray diffraction, Fourier-transform infrared spectroscopy, micromeritics N2 adsorption/desorption analysis, and field emission scanning electron microscopy. The effects of CF addition, Si/Al ratio, initial ammonium concentration, solution pH, and temperature on the adsorption of ammonium on 10% CF-Z (0...
February 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28191867/fabrication-of-polyamide-thin-film-nanocomposite-membranes-with-enhanced-surface-charge-for-nitrate-ion-removal-from-water-resources
#15
A Ghaee, M M Zerafat, P Askari, S Sabbaghi, B Sadatnia
Exclusion due to membrane surface charge is considered as one of the main separation mechanisms occurring in charged membranes, which can be varied through various approaches to affect membrane rejection performance. In this study, thin-film composite (TFC) polyamide (PA) membranes were fabricated via interfacial polymerization of m-phenylenediamine (m-PDA) and 2,4-diaminobenzene sulfonic acid with trimesoyl chloride (TMC) on a polysulfone sub-layer. The ability of the prepared membrane to remove nitrate ions from water resources has been investigated...
March 2017: Environmental Technology
https://www.readbyqxmd.com/read/28187926/removal-of-210-po-from-aqueous-media-and-its-thermodynamics-and-kinetics
#16
S Akyil Erenturk, A Kilincarslan Kaygun
In this study, the composite adsorbent as granule was prepared by mixing of polyacrylonitrile (PAN) and a natural zeolite (clinoptilolite) in specific conditions. The prepared composite adsorbent was used for investigating the adsorption behaviour of (210)Po. Adsorption of (210)Po was studied in a column system. The effective parameters such as initial activity concentration of (210)Po, pH of the aqueous solution, contact time and temperature of solution for adsorption behaviour of (210)Po were studied. Adsorption yield of (210)Po on composite adsorbent from aqueous solution in optimum conditions were determined as 75...
February 7, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28187387/permeable-bio-reactive-barriers-to-address-petroleum-hydrocarbon-contamination-at-subantarctic-macquarie-island
#17
Benjamin L Freidman, Deborah Terry, Dan Wilkins, Tim Spedding, Sally L Gras, Ian Snape, Geoffrey W Stevens, Kathryn A Mumford
A reliance on diesel generated power and a history of imperfect fuel management have created a legacy of petroleum hydrocarbon contamination at subantarctic Macquarie Island. Increasing environmental awareness and advances in contaminant characterisation and remediation technology have fostered an impetus to reduce the environmental risk associated with legacy sites. A funnel and gate permeable bio-reactive barrier (PRB) was installed in 2014 to address the migration of Special Antarctic Blend diesel from a spill that occurred in 2002, as well as older spills and residual contaminants in the soil at the Main Power House...
January 30, 2017: Chemosphere
https://www.readbyqxmd.com/read/28187255/redox-route-from-inorganic-precursor-li2c2-to-nanopatterned-carbon
#18
Paul Simon, Xian-Juan Feng, Matej Bobnar, Peter Höhn, Ulrich Schwarz, Wilder Carrillo-Cabrera, Michael Baitinger, Yuri Grin
We present the synthesis route to carbon with hierarchical morphology on the nanoscale. The structures are generated using crystalline orthorhombic lithium carbide (Li2C2) as precursor with nanolamellar organization. Careful treatment by SnI4 oxidizes carbon at the fairly low temperature of 80 °C to the elemental state and keeps intact the initial crystallite shape, the internal lamellar texture of particles, and the lamellae stacking. The reaction product is amorphous but displays in the microstructure parallel band-like arrangements with diameters in the range of 200-500 nm...
February 15, 2017: ACS Nano
https://www.readbyqxmd.com/read/28186217/time-and-space-resolved-study-of-the-methanol-to-hydrocarbons-mth-reaction-influence-of-zeolite-topology-on-axial-deactivation-patterns
#19
Daniel Rojo-Gama, Samaneh Etemadi, Eliot Kirby, Karl Petter Lillerud, Pablo Beato, Stian Svelle, Unni Olsbye
Zeolites representing seven different topologies were subjected to life-time assessment studies as methanol to hydrocarbons (MTH) catalysts at 400 °C, P(MeOH) = 13 kPa and P(tot) = 100 kPa. The following topologies were studied: ZSM-22 (TON), ZSM-23 (MTT), IM-5 (IMF), ITQ-13 (ITH), ZSM-5 (MFI), mordenite (MOR) and beta (BEA). Two experimental approaches were used. In the first approach, each catalyst was tested at three different contact times, all giving 100% initial conversion. The life-time before conversion decreased to 50% at each contact time was measured and used to calculate critical contact times (i...
February 10, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28184244/solid-binding-peptides-for-immobilisation-of-thermostable-enzymes-to-hydrolyse-biomass-polysaccharides
#20
Andrew Care, Kerstin Petroll, Emily S Y Gibson, Peter L Bergquist, Anwar Sunna
BACKGROUND: Solid-binding peptides (SBPs) bind strongly to a diverse range of solid materials without the need for any chemical reactions. They have been used mainly for the functionalisation of nanomaterials but little is known about their use for the immobilisation of thermostable enzymes and their feasibility in industrial-scale biocatalysis. RESULTS: A silica-binding SBP sequence was fused genetically to three thermostable hemicellulases. The resulting enzymes were active after fusion and exhibited identical pH and temperature optima but differing thermostabilities when compared to their corresponding unmodified enzymes...
2017: Biotechnology for Biofuels
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