165 research outputs found

    Comparison of Detachment Rates from Purple and Loess Soil Rills

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    A new MOF-5 homologue for selective separation of methane from C<sub>2</sub> hydrocarbons at room temperature

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    A new MOF-5 homologue compound UTSA-10 has been obtained under solvothermal conditions from a mixture of Zn(NO3)2â‹…6H2O and commercially available linker, 2-methylfumaric acid, in N,N-dimethylformamide. The moderate surface area and suitable pore sizes enable the activated UTSA-10a to separate methane from C2 hydrocarbons at room temperature

    Single and multicomponent sorption of CO2, CH4 and N-2 in a microporous metal-organic framework

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    Single and multicomponent fixed-bed adsorption of CO2, N-2, and CH4 on crystals of MOF-508b has been studied in this work. Adsorption equilibrium was measured at temperatures ranging from 303 to 343 K and partial pressures up to 4.5 bar. MOF-508b is very selective for CO2 and the loadings of CH4 and N-2 are practically temperature independent. The Langmuir isotherm model provides a good representation of the equilibrium data. A dynamic model based on the LDF approximation for the mass transfer has been used to describe with good accuracy the adsorption kinetics of single, binary and ternary breakthrough curves. It was found that the intra-crystalline diffusivity for CO2 is one order of magnitude faster than for CH4 and N-2.This work was supported by an Award CHE 0718281 from the National Science Foundation (B.C.), the University of Texas-Pan American (UTPA) through a Faculty Research Council Award (B.C), in part by the Welch Foundation (Grant BG-0017) to the Department of Chemistry at UTPA. J.A.C.S. acknowledges financial support provided by national research grant FCT=POCTI=EQU=60828=2004 and by LSRE financing by FEDER=POCI=2010. P.S.B. acknowledges his Ph.D. scholarship by FCT (SFRH=BD=30994=2006), and L.B. acknowledges Henri Pieper Grant (Institute HEMES Gramme, Belgium) for the financial support

    Modeling adsorption equilibria of xylene isomers in a microporous metal–organic framework

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    Single and multicomponent adsorption equilibria of xylene isomers: o-xylene (o-x), m-xylene (m-x), pxylene (p-x) and ethylbenzene (eb) was investigated on the three dimensional microporous metal–organic framework Zn(BDC)(Dabco)0.5 (BDC = 1,4-benzenedicarboxylate, Dabco = 1,4-diazabicyclo[2.2.2]-octane), MOF 1, in the range of temperatures between 398 and 448 K and partial pressures up to 0.1 bar. The equilibrium data show that a significant amount (around 34 g/100gads at 398 K) of xylene isomers can be adsorbed in MOF 1. The affinity to the adsorbent measured by the Henry’s constants to decreases in the order o-x > m-x > eb > p-x for all temperatures. The zero coverage adsorption enthalpies are all similar and range from 77.4 (eb) to 79.8 kJ/mol (o-x). The Dual-Site Langmuir model (DSL) was used for the interpretation and correlation of the experimental data. The parameters obtained from the pure component isotherms fitting were also used to predict the multicomponent equilibrium data by an extended DSL model. A good agreement was obtained between the predictions and the experimental data. It was also demonstrated that the DSL model is also capable to explain the increase in the isosteric heat of sorption with increasing coverage.José A.C. Silva acknowledges the financial support from Fundação para a Ciência e Tecnologia under Project POCI/EQU/ 60828/2004. Patrick S. Bárcia acknowledges a FCT PhD Grant (SFRH/BD/30994/2006). This work was supported by an Award CHE 0718281 from the NSF (BC)

    A microporous metal-organic framework for separation of CO2/N-2 and CO2/CH4 by fixed-bed adsorption

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    A microporous MOF Zn(BDC)(4,4'-Bipy)0.5 (MOF-508b, BDC = 1,4-benzenedicarboxylate, 4,4'-Bipy = 4,4'-bipyridine) was examined for the separation and removal of CO2 from its binary CO2/N-2 and CO2/CH4 and ternary CO2/CH4/N-2 mixtures by fixed-bed adsorption. With one-dimensional pores of about 4.0 x 4.0 angstrom to induce their differential interactions with the three components, MOF-508b exhibits highly selective adsorption to CO2 with the,adsorption capacity of 26.0 wt % at 303 K and 4.5 bar. This is the first example of microporous MOFs for the separation and removal of CO2 from its binary and ternary mixtures by fixed-bed adsorption, establishing the feasibility of the emerging microporous MOFs for their potential. applications in this very important industrial and environmental process

    Fine Tuning the Pore Surface in Zirconium Metal−Organic Frameworks for Selective Ethane/Ethylene Separation

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    Ethylene is an important chemical feedstock for production of polymers and high-value organic chemicals, and yet its conventional purification process is plagued with high consumption of energy. Metal−organic frameworks (MOFs) provide a suitable adsorption platform for selective ethane/ ethylene separation thanks to their structural diversity, tunable pore characteristics, designable pore sizes, and high pore volumes. Although there are empirical design rules like avoiding open metal sites and creating nonpolar pore surfaces for development of adsorptive MOFs, it is still challenging to design robust MOFs that can realize direct ethane-selective separation. Herein, we systematically designed and synthesized three Zr-MOFs based on the assembly of angular ligands and 12-connected Zr6 clusters that feature the pcu network structure. By changing the size and flexibility of the substituent on the angular ligand, we were able to prevent interpenetration and identified NPF-802, which exhibits good C2H6/C2H4 separation performance that is attributed to the bulky and inert tert-butyl groups of its carbazole ligand. This work provides insights for design of ligands of MOFs with suitable pore environments to address important and challenging gas separations

    Vektor Malaria Baru di Kabupaten Kotabaru, Provinsi Kalimantan Selatan, Indonesia

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    Nyamuk Anopheles merupakan vektor dari Malaria. Dari sekitar 400 spesies nyamuk Anopheles telah ditemukan 67 spesies dapat menularkan malaria dan 24 diantaranya ditemukan di Indonesia. Kabupaten Kotabaru merupakan kabupaten endemis malaria di Kalimantan Selatan. Data mengenai spesies vektor malaria spesifik pada suatu daerah sangat berperan penting sebagai salah satu bahan rekomendasi bagi tindak lanjut kebijakan pengendalian malaria. Penelitian bertujuan untuk mengetahui data vektor malaria di Kabupaten Kotabaru melalui uji PCR. Penelitian deskriptif dengan desain cross sectional. Penangkapan nyamuk dilakukan di Desa Siayuh Trans dan Magalau Hulu, tambang emas Kura-Kura dan Desa Muara Uri dengan metode penangkapan UOL, UOD, dinding dan kandang. Uji PCR dilaksanakan di laboratorium biomolekuler BBPPVRP Salatiga pada bulan Februari-April 2015. Hasil penangkapan nyamuk didapatkan 345 ekor nyamuk Anopheles yang terdiri dari 9 spesies: An. barbirostris, An. tesselatus, An. balabacensis, An. vagus, An. hyrcanus group, An. peditaeniatus, An. kochi, An. flavirostris, An. umbrosus. Seluruh nyamuk Anopheles yang didapatkan dibuat 56 pool sampel Anopheles sp untuk diuji PCR yang telah diklasifikasikan berdasarkan spesies, tanggal dan metode penangkapan. Hasil PCR terindentifikasi 3 spesies vektor malaria di Desa Siayuh Trans yaitu An. vagus, An. peditaeniatus dan An. tesselatus yang merupakan vektor malaria baru di Propinsi Kalimantan Selatan
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