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Sample records for boracite-network-topology porous mof

  1. Activation of porous MOF materials

    Science.gov (United States)

    Hupp, Joseph T; Farha, Omar K

    2013-04-23

    A method for the treatment of solvent-containing MOF material to increase its internal surface area involves introducing a liquid into the MOF in which liquid the solvent is miscible, subjecting the MOF to supercritical conditions for a time to form supercritical fluid, and releasing the supercritical conditions to remove the supercritical fluid from the MOF. Prior to introducing the liquid into the MOF, occluded reaction solvent, such as DEF or DMF, in the MOF can be exchanged for the miscible solvent.

  2. Design and Synthesis of Novel Porous Metal-Organic Frameworks (MOFs) Toward High Hydrogen Storage Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Eddaoudi [USF; Zaworotko, Michael [USF; Space, Brian [USF; Eckert, Juergen [USF

    2013-05-08

    Statement of Objectives: 1. Synthesize viable porous MOFs for high H2 storage at ambient conditions to be assessed by measuring H2 uptake. 2. Develop a better understanding of the operative interactions of the sorbed H2 with the organic and inorganic constituents of the sorbent MOF by means of inelastic neutron scattering (INS, to characterize the H2-MOF interactions) and computational studies (to interpret the data and predict novel materials suitable for high H2 uptake at moderate temperatures and relatively low pressures). 3. Synergistically combine the outcomes of objectives 1 and 2 to construct a made-to-order inexpensive MOF that is suitable for super H2 storage and meets the DOE targets - 6% H2 per weight (2kWh/kg) by 2010 and 9% H2 per weight (3kWh/kg) by 2015. The ongoing research is a collaborative experimental and computational effort focused on assessing H2 storage and interactions with pre-selected metal-organic frameworks (MOFs) and zeolite-like MOFs (ZMOFs), with the eventual goal of synthesizing made-to-order high H2 storage materials to achieve the DOE targets for mobile applications. We proposed in this funded research to increase the amount of H2 uptake, as well as tune the interactions (i.e. isosteric heats of adsorption), by targeting readily tunable MOFs:

  3. Porous carbon derived from Metal–organic framework (MOF) for capacitive deionization electrode

    International Nuclear Information System (INIS)

    Highlights: • Porous carbons (PC) were obtained from the carbonization of MOF-5. • The PC-900 exhibited much higher electrochemical performance than AC. • The PCs derived from MOF-5 were investigated for CDI. • The maximum electrosorption capacity of 9.39 mg g−1 was obtained by PC-900. - Abstract: Porous carbon (PC) was easily prepared by synthesis of a metal–organic framework (MOF-5) followed by carbonization step. The morphology, structure, Brunauer-Emmett-Teller (BET) surface areas, wettability, and electrochemical performance for PCs carbonized at different temperatures from 500 to 1000 °C were characterized by the techniques of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), N2 adsorption-desorption, contact angle of glycerin, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), and compared with a commercially available activated carbon (AC). The results showed that MOF-5 was fully carbonated at 900 °C, having the highest specific surface area of 1563.09 m2 g−1 and the largest pore volume of 1.07 cm3 g−1. The PC carbonized at 900 °C (PC-900) exhibited better wettability, a higher specific capacity and a lower charge transfer resistance than other PCs and AC. In further capacitive deionization (CDI) process, the PC-900 electrode exhibited 9.39 mg g−1 CDI capacity, significantly higher than 5.47 mg g−1 of AC electrode. More importantly, easy and good repeatability could be obtained for PC-900 electrode. This study suggests that the PC-900 derived from MOF-5 may be a potential electrode material for CDI

  4. A “green” strategy to construct non-covalent, stable and bioactive coatings on porous MOF nanoparticles

    Science.gov (United States)

    Agostoni, V.; Horcajada, P.; Noiray, M.; Malanga, M.; Aykaç, A.; Jicsinszky, L.; Vargas-Berenguel, A.; Semiramoth, N.; Daoud-Mahammed, S.; Nicolas, V.; Martineau, C.; Taulelle, F.; Vigneron, J.; Etcheberry, A.; Serre, C.; Gref, R.

    2015-01-01

    Nanoparticles made of metal-organic frameworks (nanoMOFs) attract a growing interest in gas storage, separation, catalysis, sensing and more recently, biomedicine. Achieving stable, versatile coatings on highly porous nanoMOFs without altering their ability to adsorb molecules of interest represents today a major challenge. Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings. Cyclodextrin molecules bearing strong iron complexing groups (phosphates) were firmly anchored to the nanoMOFs' surface, within only a few minutes, simply by incubation with aqueous nanoMOF suspensions. The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities. The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system. These results pave the way towards the design of surface-engineered nanoMOFs of interest for applications in the field of targeted drug delivery, catalysis, separation and sensing.

  5. Low-temperature loading of Cu+ species over porous metal-organic frameworks (MOFs) and adsorptive desulfurization with Cu+-loaded MOFs.

    Science.gov (United States)

    Khan, Nazmul Abedin; Jhung, Sung Hwa

    2012-10-30

    Porous metal-organic frameworks (MOFs, MIL-100-Fe, iron-benzenetricarboxylate) supported with Cu(+) species were obtained for the first time under mild condition without high temperature calcinations. The Cu(+)-loaded MOFs were evaluated as efficient adsorbents for the liquid-phase adsorption of benzothiophene (BT). The effect of Cu(+) loading on the adsorption kinetics and maximum adsorption capacity (Q(0)) for the adsorption of BT was also studied. Q(0) increased with increasing copper loading up to a Cu/Fe (wt./wt.) ratio of 0.07 in Cu(+)-loaded-MIL-100-Fe, resulting in an increase in the Q(0) by 14% compared with the virgin MIL-100-Fe without Cu(+) ions. Since the surface area and pore volume decrease with the loading of copper, the increased Q(0) over the Cu(+)-loaded MIL-100-Fe adsorbents suggests specific favorable interactions (probably by π-complexation) between Cu(+) and BT. PMID:22959132

  6. Incorporating polyoxometalates into a porous MOF greatly improves its selective adsorption of cationic dyes.

    Science.gov (United States)

    Yan, Ai-Xue; Yao, Shuang; Li, Yang-Guang; Zhang, Zhi-Ming; Lu, Ying; Chen, Wei-Lin; Wang, En-Bo

    2014-06-01

    Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL-101 resulting in a series of POM-MOF composite materials POM@MIL-101 (POM = K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one-pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr(3+) ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy-dispersive X-ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL-101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL-101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL-101. An uptake capacity of 371 mg g(-1), comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL-101 in the methylene blue (MB) solution (100 mL of 100 mg L(-1) MB solution). Further study revealed that the POM@MIL-101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL-101 (10 mg) towards MB (100 mL of 10 mg L(-1)) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL-101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process. PMID:24737342

  7. A 3D porous zinc MOF constructed from a flexible tripodal ligand: Synthesis, structure, and photoluminescence property

    International Nuclear Information System (INIS)

    A new metal-organic framework, [Zn5(trencba)2(OH)2Cl2.4H2O] (1) [H3trencba=N,N,N',N',N'',N''-tris[(4-carboxylate-2-yl)methyl]-tris (2-aminoethyl)amine], constructed from a flexible tripodal ligand based on C3 symmetric tris(2-aminoethyl)amine, has been synthesized hydrothermally and characterized by elemental analysis, IR, TG, XRD and single-crystal X-ray diffraction analysis. Compound 1 contains an unprecedented linear penta-nuclear zinc cluster fragment. Each ligand links four penta-nuclear fragments, and every fragment links eight ligands to generate a three-dimensional non-interpenetrated porous framework. The uncoordinated water molecules were observed trapped in the void pores. Compound 1 represents the first example of (6,8)-connected 3D bi-nodal framework based on a single kind of organic ligand. The photoluminescence measurements showed that complex 1 exhibits relatively stronger blue emissions at room temperature than that of the ligand. - Graphical abstract: The MOF [Zn5(trencba)2(OH)2Cl2.4H2O] (H3trencba=N,N,N',N',N',N'-tris[(4-carboxylate-2-yl)methyl]-tris (2-aminoethyl)amine) reveals a (6,8)-connected bi-nodal three-dimensional porous framework with unprecedented penta-nuclear fragment, which appears to be a good candidate of hybrid inorganic-organic photoactive materials

  8. Porous carbon as electrode material in direct ethanol fuel cells (DEFCs) synthesized by the direct carbonization of MOF-5

    KAUST Repository

    Khan, Inayatali

    2014-01-12

    Porous carbon (PC-900) was prepared by direct carbonization of porous metal-organic framework (MOF)-5 (Zn4O(bdc)3, bdc=1,4-benzenedicarboxylate) at 900 °C. The carbon material was deposited with PtM (M=Fe, Ni, Co, and Cu (20 %) metal loading) nanoparticles using the polyol reduction method, and catalysts PtM/PC-900 were designed for direct ethanol fuel cells (DEFCs). However, herein, we are reporting PtFe/PC-900 catalyst combination which has exhibited superior performance among other options. This catalyst was characterized by powder XRD, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) technique. The electrocatalytic capability of the catalyst for ethanol electrooxidation was investigated using cyclic voltammetry and direct ethanol single cell testing. The results were compared with those of PtFe and Pt supported on Vulcan XC72 carbon catalysts (PFe/CX-72 and Pt/XC-72) prepared via the same method. It has been observed that the catalyst PtFe/PC-900 developed in this work showed an outstanding normalized activity per gram of Pt (6.8 mA/g Pt) and superior power density (121 mW/cm2 at 90 °C) compared to commercially available carbon-supported catalysts. © Springer-Verlag Berlin Heidelberg 2014.

  9. Cobalt nanoparticle-embedded carbon nanotube/porous carbon hybrid derived from MOF-encapsulated Co3O4 for oxygen electrocatalysis.

    Science.gov (United States)

    Dou, Shuo; Li, Xingyue; Tao, Li; Huo, Jia; Wang, Shuangyin

    2016-08-11

    We successfully obtained a novel bi-functional electrocatalyst towards the ORR and OER: Co nanoparticle-embedded N-doped carbon nanotube (CNT)/porous carbon (PC) by pyrolyzing metal organic framework (MOF) encapsulated Co3O4. The as-obtained hybrid exhibited highly efficient electrocatalytic activity for the ORR and OER. Furthermore, the assembled Zn-air batteries also revealed promising performance and long-term stability. PMID:27411845

  10. Colorometric detection of water using MOF-polymer films and composites

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Talin, Albert Alec

    2016-05-24

    A method including exposing a mixture of a porous metal organic framework (MOF) and a polymer to a predetermined molecular species, wherein the MOF has an open metal site for the predetermined molecular species and the polymer has a porosity for the predetermined molecular species; and detecting a color change of the MOF in the presence of the predetermined molecular species. A method including combining a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species. An article of manufacture including a mixture of a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species.

  11. U(VI) capture from aqueous solution by highly porous and stable MOFs. UiO-66 and its amine derivative

    International Nuclear Information System (INIS)

    Metal-organic frameworks (MOFs) UiO-66 and its amine derivative (UiO-66-NH2) with high surface area and unprecedented chemical stability were synthesized and first explored for U(VI) capture from aqueous solutions. At pH 5.5, U(VI) sorption reach equilibrium in ca. 4 h and the maximum sorption capacity is more than 100 mg g-1. Moreover, they show desirable selectivity towards U(VI) over a range of competing metal ions. Sorption results demonstrate that introduction of amino groups into MOFs does not enhance U(VI) sorption, probably result from the lower activity of aromatic amines, decrease of surface area and formation of intermolecular hydrogen bonds. (author)

  12. MOF作模板制备多孔Au/CuxO催化剂及其CO氧化性能%MOF-templated preparation of porous Au/CuxO catalysts with octahedral structures for CO oxidation

    Institute of Scientific and Technical Information of China (English)

    刘朋飞; 张所瀛; 杨祝红; 陆小华

    2016-01-01

    采用MOF材料作模板,通过在Cu-BTC材料表面预先负载贵金属Au再热解的方法,成功制备了具有正八面体结构的新型多孔Au/CuxO负载型催化剂。通过降低热解环境中的O2浓度,调节氧化时间,实现了Au/Cu-BTC氧化产物组分的调节,分别制得了Au/Cu2O、Au/Cu2O-CuO、Au/CuO复合催化材料。将其用于CO催化氧化,发现所有Au/CuxO催化剂都表现出比Cu-BTC和Au/Cu-BTC更优异的催化性能,其中由于拥有较高的比表面积、Cu2O含量以及更好的Au的分散性,Au/Cu2O的CO氧化活性最佳,180℃即能实现CO的完全转化。%More recently, metal-organic frameworks (MOFs), as a excellent sacrificial template, have been widely used to fabricate a variety of porous metal oxides with special structures and performances. To take full advantage of MOFs in composition regulation, herein a novel method to prepare porous Au/CuxO composites with octahedral structures inherited from MOFs was introduced. Au/Cu-BTC was firstly prepared by the traditional deposition-precipitation method. Subsequently, pyrolysis of Au/Cu-BTC was conducted in 2% (volume fraction) O2 balanced with helium. By varying the time of heating, Au/CuxO composites including Au/Cu2O, Au/Cu2O-CuO and Au/CuO were successfully achieved. When tested in CO oxidation, these supported catalysts exhibited much better catalytic performances than Cu-BTC and Au/Cu-BTC due to the more active support of metal oxides. Thus, Au/Cu2O showed the best catalytic activity since the high surface area, Cu2O content and better dispersion of Au.

  13. Ligand flexibility and framework rearrangement in a new family of porous metal-organic frameworks

    DEFF Research Database (Denmark)

    Hawxwell, Samuel M; Espallargas, Guillermo Mínguez; Bradshaw, Darren; Rosseinsky, Matthew J; Prior, Timothy J; Florence, Alastair J; van de Streek, Jacco; Brammer, Lee

    Ligand flexibility permits framework rearrangement upon evacuation and gas uptake in a new family of porous MOFs.......Ligand flexibility permits framework rearrangement upon evacuation and gas uptake in a new family of porous MOFs....

  14. Metal-Organic Framework (MOF) Compounds: Photocatalysts for Redox Reactions and Solar Fuel Production.

    Science.gov (United States)

    Dhakshinamoorthy, Amarajothi; Asiri, Abdullah M; García, Hermenegildo

    2016-04-25

    Metal-organic frameworks (MOFs) are crystalline porous materials formed from bi- or multipodal organic linkers and transition-metal nodes. Some MOFs have high structural stability, combined with large flexibility in design and post-synthetic modification. MOFs can be photoresponsive through light absorption by the organic linker or the metal oxide nodes. Photoexcitation of the light absorbing units in MOFs often generates a ligand-to-metal charge-separation state that can result in photocatalytic activity. In this Review we discuss the advantages and uniqueness that MOFs offer in photocatalysis. We present the best practices to determine photocatalytic activity in MOFs and for the deposition of co-catalysts. In particular we give examples showing the photocatalytic activity of MOFs in H2 evolution, CO2 reduction, photooxygenation, and photoreduction. PMID:26970539

  15. Homochiral porous metal-organic frameworks: Why and how?

    International Nuclear Information System (INIS)

    This paper highlights the most significant recent advances in the synthesis, characterization, and applications of single-crystalline homochiral porous metal-organic frameworks (MOFs). The motivations for the synthesis of homochiral porous solids and the strategies on how they can be designed are provided. The latest examples of chiral separation and Lewis acid heterogeneous asymmetric catalysis using homochiral porous MOFs are presented

  16. Cd(ii)-MOF-IM: post-synthesis functionalization of a Cd(ii)-MOF as a triphase transfer catalyst.

    Science.gov (United States)

    Wang, Jian-Cheng; Ma, Jian-Ping; Liu, Qi-Kui; Hu, Yu-Hong; Dong, Yu-Bin

    2016-05-19

    A robust and porous Cd(ii)-MOF based on a bent imidazole-bridged ligand was synthesized and post-synthetically functionalized with linear alkyl chains to afford imidazolium salt (IM)-type triphase transfer catalysts for organic transformations. The imidazolium salt decorated Cd(ii)-MOF-IM exhibits typical solid phase transfer catalytic behavior for the azidation and thiolation of bromoalkane between aqueous/organic phases. Moreover, they can be easily recovered and reused under the PTC conditions. Cd(ii)-MOF-IM herein created a versatile family of solid phase transfer catalysts for promoting a broad scope of reactions carried out in a biphasic mixture of two immiscible solvents. PMID:27039710

  17. MOF Crystal Chemistry Paving the Way to Gas Storage Needs: Aluminum Based soc-MOF for CH4, O2 and CO2 Storage

    KAUST Repository

    Alezi, Dalal

    2015-09-28

    The molecular building block approach was employed effectively to construct a series of novel isoreticular, highly porous and stable, aluminum based Metal-Organic Frameworks with soc topology. From this platform, three compounds were experimentally isolated and fully characterized, namely, the parent Al-soc-MOF-1 and its naphthalene and anthracene analogues. Al-soc-MOF-1 exhibits outstanding gravimetric methane uptake (total and working capacity). It is shown experimentally, for the first time, that the Al-soc-MOF platform can address the challenging Department of Energy dual target of 0.5 g/g (gravimetric) and 264 cm3 (STP)/cm3 (volumetric) methane storage. Furthermore, Al-soc-MOF exhibited the highest total gravimetric and volumetric uptake for carbon dioxide and the utmost total and deliverable uptake for oxygen at relatively high pressures among all microporous MOFs. In order to correlate the MOF pore structure and functionality to the gas storage properties, to better understand the structure-properties relationship, we performed a molecular simulation study and evaluated the methane storage performance of Al-soc-MOF platform using diverse organic linkers. It was found that shortening the parent Al-soc-MOF-1 linker resulted in a noticeable enhancement in the working volumetric capacity at specific temperatures and pressures with amply conserved gravimetric uptake/working capacity. In contrast, further expansion of the organic linker (branches and/or core) led to isostructural Al-soc-MOFs with enhanced gravimetric uptake but noticeably lower volumetric capacity. The collective experimental and simulation studies indicated that the parent Al-soc-MOF-1 exhibits the best compromise between the volumetric and gravimetric total and working uptakes in a wide range of pressure and temperature conditions.

  18. Synthesis and Characterization of Metal-Organic Frameworks (MOFs) That Are Difficult to Access De Novo

    Science.gov (United States)

    Karagiaridi, Olga

    Metal-organic frameworks (MOFs) are a class of intriguing hybrid materials, comprised of metal-based nodes joined by organic linkers into a crystalline, porous, three-dimensional lattice. Their signature properties (well-defined surfaces, tailorability and ultra-high porosity) render them promising candidates for many applications, including, but not limited to, gas storage, gas separation, catalysis and sensing. One of the greatest challenges associated with MOF synthesis lies in the fact that obtaining a desired MOF structure that is tailored to perform a specific application is often not trivial. Traditional synthetic pathways termed "de novo synthesis" (typically one-pot reactions between the MOF structural building blocks under solvothermal conditions) often give rise to side products that do not possess the desired structure. To circumvent this problem, we have studied in depth two powerful MOF synthetic techniques -- solvent-assisted linker exchange (SALE) and transmetalation. These are heterogeneous reactions of parent MOF crystals with concentrated solutions of organic linkers and inorganic metal salts, respectively, that lead to the replacement of the linkers or metal nodes within the parent MOFs by the desired components, while the overall framework topology is preserved. The projects described in this dissertation have aimed to apply these techniques to transform simple (unfunctionalized) and easy to synthesize representative materials from various MOF systems to structurally and functionally interesting daughter products. Examples include synthesis of MOFs that are energetically "unfavorable", extension of MOF cages by longer linker incorporation, functionalization of MOF pores and endowment of MOFs with permanent and persistent porosity. Through these projects, we have been able to formulate a set of rules that can be applied to predict the successful outcome of SALE. Since the allure of MOFs lies in their applications, expanding the range of

  19. Tunable porous structure of metal organic framework derived carbon and the application in lithium-sulfur batteries

    Science.gov (United States)

    Li, Xia; Sun, Qian; Liu, Jian; Xiao, Biwei; Li, Ruying; Sun, Xueliang

    2016-01-01

    For the first time, we report a facile approach to fabricate metal organic framework derived carbon (MOF-C) with tunable porous structure. Different from direct pyrolysis of MOFs and blind attempt in application, the in-situ ammonia treatment enables MOF-C with desired porous structure from enriched microporous structure to hierarchically mesoporous structure. Further, NH3 treated MOF-C as carbon host for sulfur loading performing as the cathode for Li-S batteries results in twice higher capacity retention than that of pristine MOF-C. Besides, different Li-S electrochemical mechanisms regarding the different porous structures of carbon are also revealed and investigated in this paper.

  20. The Road to MOF-Related Functional Materials and Beyond: Desire, Design, Decoration, and Development.

    Science.gov (United States)

    Chen, Junying; Li, Yingwei

    2016-06-01

    Metal-organic frameworks (MOFs), which are known as a class of porous coordination polymers, have proven to be of great significance to manifold applications, owing to their fascinating topology, ultrahigh porosity, enormous internal surface area, and the combination of being as rigid as inorganic materials and as flexible as organic materials . In this review, we give a concise history of the development of MOFs as functional materials prior to our entry into this area in 2006, then a summary of our road to participate in and extend the outline of the research in MOFs chemistry, as well as the challenge in further designing applicable functional materials. We describe not only the road of evolution from the past, present, and future of this chemistry, but also the road to finalize a functional material from the desire to the design, synthesis, and postmodification of a MOF. Throughout the review, we particularly emphasize the improvements in the application of MOFs as heterogeneous catalysts, such as employing MOFs as one component for the construction of composites, and their extended scope in tough catalytic reactions. Examples of applications in gas storage and separation, small molecular sensing, and our perspectives for future applications triggered by MOFs, are also introduced. PMID:27185058

  1. Molecular simulation of polar molecules interaction with MOFs family materials

    International Nuclear Information System (INIS)

    The topic of this thesis is the adsorption of simple molecular fluids in nano-porous materials. Many industrial processes are based on this phenomenon, including ionic exchange, selective separation and heterogeneous catalysis. I used molecular simulation to study the adsorption properties of polar molecules of industrial interest (CO2 and H2O) in a new class of crystalline microporous hybrid organic-inorganic materials called Metal-Organic Frameworks (MOFs). They have exceptional adsorption properties due to their topological variety and their versatility, allowed by the large range of possibilities offered by organic and coordination chemistry and functionalizations. I first studied the adsorption of CO2 in a family of materials called IRMOFs, which share the same topology but have different porous volume, in order to characterize the effect of confinement on their adsorption performance. In particular, a general behavior has been highlighted: the critical temperature decreases when the confinement increases. Then, I looked at a recently synthesized cationic MOF called Zn2(CBTACN). After having localized the extra-framework halogen anions in the unit cell of the material, something which was not possible experimentally, I characterized CO2 adsorption in this system first as a pure gas and then as a component of different mixtures. Finally, I was interested in the hydrothermal stability of MOFs, a crucial issue for their use in industrial applications. I observed the hydration mechanism of system that is analogous to the MOF-5 (IRMOF-0h) and shed light on some collaborative effects of the attack of water that were unknown to in the literature. (author)

  2. Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

    Science.gov (United States)

    Anstoetz, Manuela; Rose, Terry J; Clark, Malcolm W; Yee, Lachlan H; Raymond, Carolyn A; Vancov, Tony

    2015-01-01

    A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha(-1)). While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils. PMID:26633174

  3. Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs: Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

    Directory of Open Access Journals (Sweden)

    Manuela Anstoetz

    Full Text Available A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF was investigated as a microbially-induced slow-release nitrogen (N and phosphorus (P fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate and N (urea fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha(-1. While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils.

  4. Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

    Science.gov (United States)

    Anstoetz, Manuela; Rose, Terry J.; Clark, Malcolm W.; Yee, Lachlan H.; Raymond, Carolyn A.; Vancov, Tony

    2015-01-01

    A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha-1). While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils. PMID:26633174

  5. Versatile Rare Earth Hexanuclear Clusters for the Design and Synthesis of Highly-connected ftw-MOFs

    KAUST Repository

    Eddaoudi, Mohamed

    2015-04-15

    A series of highly porous MOFs were deliberately targeted to contain a 12-connected rare earth hexanuclear cluster and quadrangular tetracarboxylate ligands. The resultant MOFs have an underlying topology of ftw, (4, 12)-c ftw-MOFs. This targeted RE ftw-MOF platform offers potential to assess the effect of pore functionality and size, via ligand functionalization and/or expansion, on adsorption properties of relevant gases. Examination of gas adsorption properties of these compounds showed that the ftw-MOF-2 analogues, constructed from rigid ligands having a phenyl, a naphthyl or an anthracene core, exhibited a relatively high degree of porosity. The specific surface areas and pore volumes of these analogs are amongst the highest reported for rare earth based MOFs. Further studies reveal that Y-ftw-MOF-2 shows promising attributes as a storage media for methane (CH4) at high pressures. Furthermore, Y-ftw-MOF-2 shows potential as a separation agent for the selective removal of normal butane (n-C4H10) and propane (C3H8) from natural gas (NG) as well as interesting properties for the selective separation of n-C4H10 from C3H8 or isobutane (iso-C4H10).

  6. Synthesis of MOF-199 and application to CO2 adsorption

    International Nuclear Information System (INIS)

    In this study a metal-organic framework (MOF-199) has been synthesized by solvent-thermal method. The conditions of preparation and activation processes have been investigated. The obtained material was characterized by methods of x-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimatric analysis (TGA) and scanning electron microscopy (SEM). The CO2 adsorption measurements were carried out on a high pressure volumetric analyzer (Micromeritics HPVA − 100). According to experimental results, Cu(NO3)2·3H2O has been shown to be the best copper(II) precursor for the synthesis of MOF-199 and N,N-dimethylformamide (DMF):C2H5OH:H2O with the ratio of 1:1:1 has been chosen as the most suitable solvent. The appropriate activation condition has been determined as follows: activate at 200 °C for 5 h and use CH3OH as the solvent to remove DMF. At the optimal conditions, an octahedral shape and three-dimensional (3D) structure of crystallite of MOF-199 was obtained. The synthesized MOF-199 expressed a high value of specific surface area (1448 m2 g−1 by Brunauer–Emmet–Teller (BET) method and 2028 m2 g−1 by Langmuir method) with Ta porous size of crystal of 11.8 Å and specific volume of 0.693 cm3 g−1; it was still stable up to 332 °C and its CO2 storage capacity reached to 206.59 cm3 (STP) g−1 at 25.76 bar. (paper)

  7. Computational Methods for MOF/Polymer Membranes.

    Science.gov (United States)

    Erucar, Ilknur; Keskin, Seda

    2016-04-01

    Metal-organic framework (MOF)/polymer mixed matrix membranes (MMMs) have received significant interest in the last decade. MOFs are incorporated into polymers to make MMMs that exhibit improved gas permeability and selectivity compared with pure polymer membranes. The fundamental challenge in this area is to choose the appropriate MOF/polymer combinations for a gas separation of interest. Even if a single polymer is considered, there are thousands of MOFs that could potentially be used as fillers in MMMs. As a result, there has been a large demand for computational studies that can accurately predict the gas separation performance of MOF/polymer MMMs prior to experiments. We have developed computational approaches to assess gas separation potentials of MOF/polymer MMMs and used them to identify the most promising MOF/polymer pairs. In this Personal Account, we aim to provide a critical overview of current computational methods for modeling MOF/polymer MMMs. We give our perspective on the background, successes, and failures that led to developments in this area and discuss the opportunities and challenges of using computational methods for MOF/polymer MMMs. PMID:26842308

  8. Geometrical Properties Can Predict CO2 and N2 Adsorption Performance of Metal-Organic Frameworks (MOFs) at Low Pressure.

    Science.gov (United States)

    Fernandez, Michael; Barnard, Amanda S

    2016-05-01

    Metal-organic frameworks (MOFs) are nanoporous materials with exceptional host-guest properties poised for groundbreaking innovations in gas separation applications according to high-throughput (HT) screening data. However, MOF structural libraries are nearly infinite in practice and so statistical and information technology will play a fundamental role in implementing and rationalizing MOF virtual screening. In this work, we apply k-means clustering and archetypal analysis (AA) to identify the truly significant nanoporous structures in a large library of ∼82 000 virtual MOFs. Quantitative structure-property relationship (QSPR) models of the theoretical CO2 and N2 uptake capacities were also developed using a calibration set of ∼16 000 hypothetical MOF structures derived from the prototypes and archetype frameworks. Since uptake capacities correlated poorly to the void fraction, surface area and pore size but these properties were used to build binary classifier predictors that successfully identify "high-performing" nanoporous materials in an external test set of ∼65 000 MOFs with accuracy higher than 94%. The accuracy of the classification decreased for MOFs with fluorine substituents. The classification models can serve as efficient filtering tools to detecting promising high-performing candidates at the early stage of virtual high-throughput screening of novel porous materials. PMID:27022760

  9. Co(II)-doped MOF-5 nano/microcrystals: Solvatochromic behaviour, sensing solvent molecules and gas sorption property

    International Nuclear Information System (INIS)

    Co(II)-doped MOF-5 nano/microcrystals with controllable morphology and size were successfully obtained by solvothermal method. The products were characterized by powder X-ray diffraction (PXRD), energy dispersive spectrometry (EDS), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), inductively coupled plasma optical emission spectrometer (ICP-OES), elemental analysis, UV–vis and infrared (IR) spectroscopy. The factors influencing the crystal morphology and size were investigated. The gas sorption measurements reveal that highly crystalline particles have large Langmuir surface area. It was found that the Co(II)-doped MOF-5 shows enhanced hydrostability and the sorption profiles of the Co(II)-doped MOF-5 nano/microcrystals are dependent on the morphology and size of the particles. Porous Co(II)-doped MOF-5 is stable upon the removal of guest molecules and exhibits different colour with accommodating different solvent molecule, which means that it can act as solvatochromic sensing materials for recognition of solvent molecules. - Graphical abstract: Co(II)-doped MOF-5 nano/microcrystals with different shapes and sizes were synthesized by a facile hydrothermal method, which not only enhance gas sorption properties and structural stability of MOFs towards moisture, but also act as new sensing materials for sensing small molecules. - Highlights: • Co(II)-doped MOF-5 nano/microcrystals with controllable morphology and size were obtained. • Co(II)-doped MOF-5 nano/microcrystals enhance the structural stability towards moisture. • Co(II)-doped MOF-5 can act as new sensing material for sensing small molecules

  10. Transforming MOFs for Energy Applications Using the Guest@MOF Concept.

    Science.gov (United States)

    Ullman, Andrew M; Brown, Jonathan W; Foster, Michael E; Léonard, François; Leong, Kirsty; Stavila, Vitalie; Allendorf, Mark D

    2016-08-01

    As the world transitions from fossil fuels to clean energy sources in the coming decades, many technological challenges will require chemists and material scientists to develop new materials for applications related to energy conversion, storage, and efficiency. Because of their unprecedented adaptability, metal-organic frameworks (MOFs) will factor strongly in this portfolio. By utilizing the broad synthetic toolkit provided by the fields of organic and inorganic chemistry, MOF pores can be customized to suit a particular application. Of particular importance is the ability to tune the strength of the interaction between the MOF pores and guest molecules. By cleverly controlling these MOF-guest interactions, the chemist may impart new function into the Guest@MOF materials otherwise lacking in vacant MOF. Herein, we highlight the concept of the Guest@MOF as it relates to our efforts to develop these materials for energy-related applicatons. Our work in the areas of H2 and noble gas storage, hydrogenolysis of biomass, light-harvesting, and conductive materials will be discussed. Of relevance to light-harvesting applications, we report for the first time a postsynthetic modification strategy for increasing the loading of a light-sensitive electron-donor molecule in the pores of a functionalized MIL-101 structure. Through the demonstrated versatility of these approaches, we show that, by treating guest molecules as integral design elements for new MOF constructs, MOF science can have a significant impact on the advancement of clean energy technologies. PMID:27399607

  11. Advanced fabrication method for the preparation of MOF thin films: Liquid-phase epitaxy approach meets spin coating method.

    KAUST Repository

    Chernikova, Valeriya

    2016-07-14

    Here we report a new and advanced method for the fabrication of highly oriented/polycrystalline metal-organic framework (MOF) thin films. Building on the attractive features of the liquid-phase epitaxy (LPE) approach, a facile spin coating method was implemented to generate MOF thin films in a high-throughput fashion. Advantageously, this approach offers a great prospective to cost-effectively construct thin-films with a significantly shortened preparation time and a lessened chemicals and solvents consumption, as compared to the conventional LPE-process. Certainly, this new spin-coating approach has been implemented successfully to construct various MOF thin films, ranging in thickness from a few micrometers down to the nanometer scale, spanning 2-D and 3-D benchmark MOF materials including Cu2(bdc)2•xH2O, Zn2(bdc)2•xH2O, HKUST-1 and ZIF-8. This method was appraised and proved effective on a variety of substrates comprising functionalized gold, silicon, glass, porous stainless steel and aluminum oxide. The facile, high-throughput and cost-effective nature of this approach, coupled with the successful thin film growth and substrate versatility, represents the next generation of methods for MOF thin film fabrication. Thereby paving the way for these unique MOF materials to address a wide range of challenges in the areas of sensing devices and membrane technology.

  12. Development of Metal–Organic Frameworks for Catalysis : Designing Functional and Porous Crystals

    OpenAIRE

    Carson, Fabian

    2015-01-01

    Metal–organic frameworks, or MOFs, have emerged as a new class of porous materials made by linking metal and organic units. The easy preparation, structural and functional tunability, ultrahigh porosity, and enormous surface areas of MOFs have led to them becoming one of the fastest growing fields in chemistry. MOFs have potential applications in numerous areas such as clean energy, adsorption and separation processes, biomedicine, and sensing. One of the most promising areas of research with...

  13. Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

    OpenAIRE

    Manuela Anstoetz; Rose, Terry J.; Clark, Malcolm W.; Yee, Lachlan H.; Raymond, Carolyn A.; Tony Vancov

    2015-01-01

    A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha(-1)). While urea hydrolysis in the O...

  14. NMR studies of benzene mobility in microporous metal-organic framework MOF-5

    International Nuclear Information System (INIS)

    Microporous metal-organic frameworks (MOF) are crystalline coordination polymers with regular three dimensional pore networks. These pore networks enable adsorption and diffusion of guest molecules. Molecular Dynamics (MD) simulations show that benzene has a liquid-like mobility inside the pores of MOF-5. Nuclear Magnetic Resonance (NMR) methods allow experimental access to guest mobilities inside such pore networks. This report presents the results of pulsed field gradient NMR (PFG NMR) self-diffusion measurements of benzene adsorbed in MOF-5. In these experiments multi-exponential spin echo decays were observed, which are usually caused by different phases of self-diffusion. These different phases of benzene mobility were unexpected for diffusion of molecules inside an isotropic framework and have to originate in the host-guest and guest-guest interaction. By modern diffusion-relaxation correlation spectroscopy (DRCOSY) translational self-diffusion and microscopic relaxation behavior were correlated. Together with magic angle spinning (MAS) NMR spectroscopy these investigations reveal that the faster component of the diffusion coefficients can be assigned to diffusion inside the porous crystal structure of MOF-5.

  15. Facile method to disperse nonporous metal organic frameworks: composite formation with a porous metal organic framework and application in adsorptive desulfurization.

    Science.gov (United States)

    Hasan, Zubair; Jhung, Sung Hwa

    2015-05-20

    It is generally not easy to utilize nonporous metal organic frameworks (MOFs) with a large crystal size (especially for catalysis or adsorption) because their surface area is low and the majority of the active sites exist inside the MOFs. Composing with porous materials may be one way to disperse the nonporous materials. In this study, a nonporous/nonsoluble MOF (in which the particle size was much larger than the cavity size of the porous MOFs) containing Cu(I) ((Cu2(pyz)2(SO4)(H2O)2)n, denoted as CP) was composed with typical porous MOFs such as MIL100(Fe) (iron-benzenetricarboxylate) and CuBTC (cupper-benzenetricarboxylate). The Cu(I) species of the nonporous MOF was effectively utilized for the adsorptive desulfurization (ADS) of model fuel. Even though the porosities of the composed MOFs decreased as the content of CP increased, the adsorption capacity increased as the content of CP increased (up to a certain content). Considering the negligible capacity of CP for ADS, the enhanced adsorption capacity may be a result of the well-dispersed Cu(I), which is known to be beneficial for ADS via π-complexation. The dispersed CP was also observed by transmission electron microscopy mapping. Therefore, composing a nonporous MOF with porous MOF is a new and facile way to disperse/utilize the active sites of a nonporous MOF. PMID:25912936

  16. Remarkable Improvement in the Mechanical Properties and CO2 Uptake of MOFs Brought About by Covalent Linking to Graphene.

    Science.gov (United States)

    Kumar, Ram; Raut, Devaraj; Ramamurty, Upadrasta; Rao, C N R

    2016-06-27

    Metal-organic frameworks (MOFs) are exceptional as gas adsorbents but their mechanical properties are poor. We present a successful strategy to improve the mechanical properties along with gas adsorption characteristics, wherein graphene (Gr) is covalently bonded with M/DOBDC (M=Mg(2+) , Ni(2+) , or Co(2+) , DOBDC=2,5-dioxido-1,4-benzene dicarboxylate) MOFs. The surface area of the graphene-MOF composites increases up to 200-300 m(2)  g(-1) whereas the CO2 uptake increases by ca. 3-5 wt % at 0.15 atm and by 6-10 wt % at 1 atm. What is significant is that the composites exhibit improved mechanical properties. In the case of Mg/DOBDC, a three-fold increase in both the elastic modulus and hardness with 5 wt % graphene reinforcement is observed. Improvement in both the mechanical properties and gas adsorption characteristics of porous MOFs on linking them to graphene is a novel observation and suggests a new avenue for the design and synthesis of porous materials. PMID:27282430

  17. Structure-property relationship of metal-organic frameworks (MOFs) and physisorbed off-gas radionuclides

    International Nuclear Information System (INIS)

    We report on the host-guest interactions between metal-organic frameworks (MOFs) with various profiles and highly polarizable molecules (iodine), with emphasis on identifying preferential sorption sites in these systems. Radioactive iodine 129I, along with other volatile radionuclides (3H, 14C, Xe and Kr), represents a relevant component in the off-gas resulted during nuclear fuel reprocessing. Due to its very long half-life, 15.7 x 106 years, and potential health risks in humans, its efficient capture and long-term storage is of great importance. The leading iodine capture technology to date is based on trapping iodine in silver-exchanged mordenite. Our interests are directed towards improving existent capturing technologies, along with developing novel materials and alternative waste forms. Herein we report the first study that systematically monitors iodine loading onto MOFs, an emerging new class of porous solid-state materials. In this context, MOFs are of particular interest as: (i) they serve as ideal high capacity storage media, (ii) they hold potential for the selective adsorption from complex streams, due to their high versatility and tunability. This work highlights studies on both newly developed in our lab, and known highly porous MOFs that all possess distinct characteristics (specific surface area, pore volume, pore size, and dimension of the window access to the pore). The materials were loaded to saturation, where elemental iodine was introduced from solution, as well as from vapor phase. Uptakes in the range of ∼125-150 wt% I2 sorbed were achieved, indicating that these materials outperform all other solid adsorbents to date in terms of overall capacity. Additionally, the loaded materials can be efficiently encapsulated in stable waste forms, including as low temperature sintering glasses. Ongoing studies are focused on gathering qualitative information with respect to localizing the physisorbed iodine molecules within the frameworks: X

  18. Structure-property relationship of metal-organic frameworks (MOFs) and physisorbed off-gas radionuclides.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Chupas, Peter J. (Argonne National Laboratory); Garino, Terry J.; Rodriguez, Mark Andrew; Chapman, Karena W. (Argonne National Laboratory); Sava, Dorina Florentina

    2010-11-01

    We report on the host-guest interactions between metal-organic frameworks (MOFs) with various profiles and highly polarizable molecules (iodine), with emphasis on identifying preferential sorption sites in these systems. Radioactive iodine 129I, along with other volatile radionuclides (3H, 14C, Xe and Kr), represents a relevant component in the off-gas resulted during nuclear fuel reprocessing. Due to its very long half-life, 15.7 x 106 years, and potential health risks in humans, its efficient capture and long-term storage is of great importance. The leading iodine capture technology to date is based on trapping iodine in silver-exchanged mordenite. Our interests are directed towards improving existent capturing technologies, along with developing novel materials and alternative waste forms. Herein we report the first study that systematically monitors iodine loading onto MOFs, an emerging new class of porous solid-state materials. In this context, MOFs are of particular interest as: (i) they serve as ideal high capacity storage media, (ii) they hold potential for the selective adsorption from complex streams, due to their high versatility and tunability. This work highlights studies on both newly developed in our lab, and known highly porous MOFs that all possess distinct characteristics (specific surface area, pore volume, pore size, and dimension of the window access to the pore). The materials were loaded to saturation, where elemental iodine was introduced from solution, as well as from vapor phase. Uptakes in the range of {approx}125-150 wt% I2 sorbed were achieved, indicating that these materials outperform all other solid adsorbents to date in terms of overall capacity. Additionally, the loaded materials can be efficiently encapsulated in stable waste forms, including as low temperature sintering glasses. Ongoing studies are focused on gathering qualitative information with respect to localizing the physisorbed iodine molecules within the frameworks: X

  19. Study of the incorporation and release of the non-conventional half-sandwich ruthenium(II) metallodrug RAPTA-C on a robust MOF.

    Science.gov (United States)

    Procopio, Elsa Quartapelle; Rojas, Sara; Padial, Natalia M; Galli, Simona; Masciocchi, Norberto; Linares, Fátima; Miguel, Delia; Oltra, J Enrique; Navarro, Jorge A R; Barea, Elisa

    2011-11-14

    The highly porous and robust [Ni(8)(OH)(4)(OH(2))(2)(4,4'-(buta-1,3-diyne-1,4-diyl)bispyrazolato)(6)](n) MOF can be used as a proof of concept for the incorporation and release of the non-conventional [Ru(p-cymene)Cl(2)(pta)] RAPTA-C metallodrug. PMID:21952589

  20. Quest for Highly-connected MOF Platforms: Rare-Earth Polynuclear Clusters Versatility Meets Net Topology Needs.

    KAUST Repository

    Alezi, Dalal

    2015-04-07

    Gaining control over the assembly of highly porous rare-earth (RE) based metal-organic frameworks (MOFs) remains challenging. Here we report the latest discoveries on our continuous quest for highly-connected nets. The topological exploration based on the non-compatibility of 12-connected RE polynuclear carboxylate-based cluster, points of extension matching the 12 vertices of the cuboctahedron (cuo), with 3-connected organic ligands led to the discovery of two fascinating and highly-connected minimal edge-transitive nets, pek and aea. The reduced symmetry of the employed triangular tricarboxylate ligand, as compared to the prototype highly symmetrical 1,3,5-benzene(tris)benzoic acid guided the concurrent occurrence of nonanuclear [RE9(μ3-OH)12(μ3-O)2(O2C–)12] and hexanuclear [RE6(OH)8(O2C–)8] carboxylate-based clusters as 12-connected and 8-connected molecular building blocks in the structure of a 3-periodic pek-MOF based on a novel (3,8,12)-c trinodal net. The use of a tricarboxylate ligand with modified angles between carboxylate moieties led to the formation of a second MOF containing solely nonanuclear clusters and exhibiting once more a novel and a highly-connected (3,12,12)-c trinodal net with aea topology. Notably, it is the first time that RE-MOFs with double six-membered ring (d6R) secondary building units are isolated, representing therefore a critical step forward toward the design of novel and highly coordinated materials using the supermolecular building layer approach while considering the d6Rs as building pillars. Lastly, the potential of these new MOFs for gas separation/storage was investigated by performing gas adsorption studies of various probe gas molecules over a wide range of pressures. Noticeably, pek-MOF-1 showed excellent volumetric CO2 and CH4 uptakes at high pressures.

  1. Single-Crystal-to-Single-Crystal Anion Exchange in a Gadolinium MOF: Incorporation of POMs and [AuCl4]−

    Directory of Open Access Journals (Sweden)

    Javier López-Cabrelles

    2016-04-01

    Full Text Available The encapsulation of functional molecules inside porous coordination polymers (also known as metal-organic frameworks, MOFs has become of great interest in recent years at the field of multifunctional materials. In this article, we present a study of the effects of size and charge in the anion exchange process of a Gd based MOF, involving molecular species like polyoxometalates (POMs, and [AuCl4]−. This post-synthetic modification has been characterized by IR, EDAX, and single crystal diffraction, which have provided unequivocal evidence of the location of the anion molecules in the framework.

  2. Simulation and Modelling of MOFs for Hydrogen Storage

    OpenAIRE

    Başdoğan, Yasemin; Keskin Avcı, Seda

    2015-01-01

    Metal organic frameworks (MOFs) have received significant attention in recent years both from academia and industry since this new class of nanoporous materials has many potential advantages over traditional nanoporous materials in gas storage and separation applications. Hydrogen storage has been one of the most widely investigated applications of MOFs and recent experimental studies have shown that several MOFs are promising for hydrogen storage at low temperatures and moderate pressures. I...

  3. MOF-based electronic and opto-electronic devices.

    Science.gov (United States)

    Stavila, V; Talin, A A; Allendorf, M D

    2014-08-21

    Metal-organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure-property relationships to identify and rationalize the factors that impact device performance. PMID:24802763

  4. Synthesis and gas adsorption study of porous metal-organic framework materials

    Science.gov (United States)

    Mu, Bin

    Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for postsynthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gasadsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structureproperty relationships of these novel adsorbents.

  5. Application of MD Simulations to Predict Membrane Properties of MOFs

    Directory of Open Access Journals (Sweden)

    Elda Adatoz

    2015-01-01

    Full Text Available Metal organic frameworks (MOFs are a new group of nanomaterials that have been widely examined for various chemical applications. Gas separation using MOF membranes has become an increasingly important research field in the last years. Several experimental studies have shown that thin-film MOF membranes can outperform well known polymer and zeolite membranes due to their higher gas permeances and selectivities. Given the very large number of available MOF materials, it is impractical to fabricate and test the performance of every single MOF membrane using purely experimental techniques. In this study, we used molecular simulations, Monte Carlo and Molecular Dynamics, to estimate both single-gas and mixture permeances of MOF membranes. Predictions of molecular simulations were compared with the experimental gas permeance data of MOF membranes in order to validate the accuracy of our computational approach. Results show that computational methodology that we described in this work can be used to accurately estimate membrane properties of MOFs prior to extensive experimental efforts.

  6. The quest for modular nanocages: Tbo -MOF as an archetype for mutual substitution, functionalization, and expansion of quadrangular pillar building blocks

    KAUST Repository

    Eubank, Jarrod F.

    2011-09-14

    A new blueprint network for the design and synthesis of porous, functional 3D metal-organic frameworks (MOFs) has been identified, namely, the tbo net. Accordingly, tbo-MOFs based on this unique (3,4)-connected net can be exclusively constructed utilizing a combination of well-known and readily targeted [M(R-BDC)]n MOF layers [i.e., supermolecular building layers (SBLs)] based on the edge-transitive 4,4 square lattice (sql) (i.e., 2D four-building units) and a novel pillaring strategy based on four proximal isophthalate ligands from neighboring SBL membered rings (i.e., two pairs from each layer) covalently cross-linked through an organic quadrangular core (e.g., tetrasubstituted benzene). Our strategy permits the rational design and synthesis of isoreticular structures, functionalized and/or expanded, that possess extra-large nanocapsule-like cages, high porosity, and potential for gas separation and storage, among others. Thus, tbo-MOF serves as an archetypal tunable, isoreticular MOF platform for targeting desired applications. © 2011 American Chemical Society.

  7. Waste polyethylene terephthalate (PET) materials as sustainable precursors for the synthesis of nanoporous MOFs, MIL-47, MIL-53(Cr, Al, Ga) and MIL-101(Cr).

    Science.gov (United States)

    Lo, Sheng-Han; Senthil Raja, Duraisamy; Chen, Chia-Wei; Kang, Yu-Hao; Chen, Jiun-Jen; Lin, Chia-Her

    2016-06-21

    In our novel green approach, the waste polyethylene terephthalate (PET) bottle material has effectively been used as the starting precursor instead of terephthalic acid for the synthesis of five terephthalate based nanoporous trivalent metal-organic frameworks (MOFs) namely MIL-47, MIL-53(Cr), MIL-53(Al), MIL-53(Ga), and MIL-101(Cr). The optimum reaction parameters to achieve the green synthesis were studied. These MOFs were structurally identified by using powder X-ray diffraction (PXRD) measurements. Scanning electron microscopy (SEM) images confirm the particle nature and size of the synthesized MOFs. Nitrogen gas sorption measurements have been done for some of the MOFs to check their porous properties. All the characterization techniques strongly supported that the synthesized MOFs using PET are similar to their literature reports. The gas adsorption studies for the synthesized MIL-53(Cr) and MIL-101(Cr) showed their significant gas uptake capability towards CO2 and H2 gases. Further, the synthesized MIL-47 and MIL-101(Cr) have been tested for their catalytic ability in chemical fixation of CO2 gas through the conversion of CO2 and epoxides to the corresponding cyclic carbonates which shows promising results to use them as catalysts. PMID:27198203

  8. Probing the structural flexibility of MOFs by constructing metal oxide@MOF-based heterostructures for size-selective photoelectrochemical response

    Science.gov (United States)

    Zhan, Wenwen; He, Yue; Guo, Jiangbin; Chen, Luning; Kong, Xiangjian; Zhao, Haixia; Kuang, Qin; Xie, Zhaoxiong; Zheng, Lansun

    2016-07-01

    It is becoming a challenge to achieve simpler characterization and wider application of flexible metal organic frameworks (MOFs) exhibiting the gate-opening or breathing behavior. Herein, we designed an intelligent MOF-based system where the gate-opening or breathing behavior of MOFs can be facially visualized in solution. Two types of metal oxide@MOF core-shell heterostructures, ZnO@ZIF-7 and ZnO@ZIF-71, were prepared using ZnO nanorods as self-sacrificial templates. The structural flexibility of both the MOFs can be easily judged from the distinct molecular-size-related formation modes and photoelectrochemical performances between the two ZnO@ZIF heterostructures. Moreover, the rotational dynamics of the flexible parts of ZIF-7 were studied by analyzing the intrinsic physical properties, such as dielectric constants, of the structure. The present work reminds us to pay particular attention to the influences of the structural flexibility of MOFs on the structure and properties of MOF-involved heterostructures in future studies.It is becoming a challenge to achieve simpler characterization and wider application of flexible metal organic frameworks (MOFs) exhibiting the gate-opening or breathing behavior. Herein, we designed an intelligent MOF-based system where the gate-opening or breathing behavior of MOFs can be facially visualized in solution. Two types of metal oxide@MOF core-shell heterostructures, ZnO@ZIF-7 and ZnO@ZIF-71, were prepared using ZnO nanorods as self-sacrificial templates. The structural flexibility of both the MOFs can be easily judged from the distinct molecular-size-related formation modes and photoelectrochemical performances between the two ZnO@ZIF heterostructures. Moreover, the rotational dynamics of the flexible parts of ZIF-7 were studied by analyzing the intrinsic physical properties, such as dielectric constants, of the structure. The present work reminds us to pay particular attention to the influences of the structural flexibility of

  9. Gas sensing using porous materials for automotive applications.

    Science.gov (United States)

    Wales, Dominic J; Grand, Julien; Ting, Valeska P; Burke, Richard D; Edler, Karen J; Bowen, Chris R; Mintova, Svetlana; Burrows, Andrew D

    2015-07-01

    Improvements in the efficiency of combustion within a vehicle can lead to reductions in the emission of harmful pollutants and increased fuel efficiency. Gas sensors have a role to play in this process, since they can provide real time feedback to vehicular fuel and emissions management systems as well as reducing the discrepancy between emissions observed in factory tests and 'real world' scenarios. In this review we survey the current state-of-the-art in using porous materials for sensing the gases relevant to automotive emissions. Two broad classes of porous material - zeolites and metal-organic frameworks (MOFs) - are introduced, and their potential for gas sensing is discussed. The adsorptive, spectroscopic and electronic techniques for sensing gases using porous materials are summarised. Examples of the use of zeolites and MOFs in the sensing of water vapour, oxygen, NOx, carbon monoxide and carbon dioxide, hydrocarbons and volatile organic compounds, ammonia, hydrogen sulfide, sulfur dioxide and hydrogen are then detailed. Both types of porous material (zeolites and MOFs) reveal great promise for the fabrication of sensors for exhaust gases and vapours due to high selectivity and sensitivity. The size and shape selectivity of the zeolite and MOF materials are controlled by variation of pore dimensions, chemical composition (hydrophilicity/hydrophobicity), crystal size and orientation, thus enabling detection and differentiation between different gases and vapours. PMID:25982991

  10. Structure and Mobility of Metal Clusters in MOFs: Au, Pd, and AuPd Clusters in MOF-74

    DEFF Research Database (Denmark)

    Vilhelmsen, Lasse; Walton, Krista S.; Sholl, David S.

    2012-01-01

    Understanding the adsorption and mobility of metal–organic framework (MOF)-supported metal nanoclusters is critical to the development of these catalytic materials. We present the first theoretical investigation of Au-, Pd-, and AuPd-supported clusters in a MOF, namely MOF-74. We combine density...... functional theory (DFT) calculations with a genetic algorithm (GA) to reliably predict the structure of the adsorbed clusters. This approach allows comparison of hundreds of adsorbed configurations for each cluster. From the investigation of Au8, Pd8, and Au4Pd4 we find that the organic part of the MOF is......’s adsorption energy and diffusion barrier is established, confirming that Au clusters are highly mobile in the MOF-74 framework and Pd clusters are less mobile....

  11. H2 Adsorption in a Porous Crystal: Accurate First-Principles Quantum Simulation.

    Science.gov (United States)

    D'Arcy, Jordan H; Jordan, Meredith J T; Frankcombe, Terry J; Collins, Michael A

    2015-12-17

    A general method is presented for constructing, from ab initio quantum chemistry calculations, the potential energy surface (PES) for H2 absorbed in a porous crystalline material. The method is illustrated for the metal-organic framework material MOF-5. Rigid body quantum diffusion Monte Carlo simulations are used in the construction of the PES and to evaluate the quantum ground state of H2 in MOF-5, the zero-point energy, and the enthalpy of adsorption at 0 K. PMID:26322374

  12. Modulations of hMOF autoacetylation by SIRT1 regulate hMOF recruitment and activities on the chromatin

    Institute of Scientific and Technical Information of China (English)

    Lu Lu; Lei Li; Xiang Lv; Xue-Song Wu; De-Pei Liu; Chih-Chuan Liang

    2011-01-01

    A wide variety of nuclear regulators and enzymes are subjected to acetylation of the lysine residue, which regulates different aspects of protein functions. The MYST family histone acetyltransferase, human ortholog of MOF (hMOF), plays critical roles in transcription activation by acetylating nucleosomai H4K16. In this study, we found that hMOF acetylates itself in vitro and in vivo, and the acetylation is restricted to the conserved MYST domain (C2HC zinc finger and HAT), of which the K274 residue is the major autoacetylation site. Furthermore, the class Ⅲ histone deacetylase SIRT1 was found to interact with the MYST domain of hMOF through the deacetylase catalytic region and deacetylate autoacetylated hMOF. In vitro binding assays showed that non-acetylated hMOF robustly binds to nucleosomes while acetylation decreases the binding ability. In HeLa cells, the recruitment of hMOF to the chromatin increases in response to SIRT1 overexpression and decreases after knockdown of SIRT1. The acetylation mimic mutation K274Q apparently decreases the chromatin recruitment of hMOF as well as the global H4K16Ac level in HeLa cells. Finally, upon SIRT1 knockdown, hMOF recruitment to the gene body region of its target gene HoxA9 decreases, accompanied with decrease of H4K16Ac at the same region and repression of HoxA9 transcription. These results suggest a dynamic interplay between SIRT1 and hMOF in regulating H4K16 acetylation.

  13. The Functional Analysis of Histone Acetyltransferase MOF in Tumorigenesis

    Science.gov (United States)

    Su, Jiaming; Wang, Fei; Cai, Yong; Jin, Jingji

    2016-01-01

    Changes in chromatin structure and heritably regulating the gene expression by epigenetic mechanisms, such as histone post-translational modification, are involved in most cellular biological processes. Thus, abnormal regulation of epigenetics is implicated in the occurrence of various diseases, including cancer. Human MOF (males absent on the first) is a member of the MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of histone acetyltransferases (HATs). As a catalytic subunit, MOF can form at least two distinct multiprotein complexes (MSL and NSL) in human cells. Both complexes can acetylate histone H4 at lysine 16 (H4K16); however, the NSL complex possesses broader substrate specificity and can also acetylate histone H4 at lysines 5 and 8 (H4K5 and H4K8), suggesting the complexity of the intracellular functions of MOF. Silencing of MOF in cells leads to genomic instability, inactivation of gene transcription, defective DNA damage repair and early embryonic lethality. Unbalanced MOF expression and its corresponding acetylation of H4K16 have been found in certain primary cancer tissues, including breast cancer, medulloblastoma, ovarian cancer, renal cell carcinoma, colorectal carcinoma, gastric cancer, as well as non-small cell lung cancer. In this review, we provide a brief overview of MOF and its corresponding histone acetylation, introduce recent research findings that link MOF functions to tumorigenesis and speculate on the potential role that may be relevant to tumorigenic pathways. PMID:26784169

  14. The Functional Analysis of Histone Acetyltransferase MOF in Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Jiaming Su

    2016-01-01

    Full Text Available Changes in chromatin structure and heritably regulating the gene expression by epigenetic mechanisms, such as histone post-translational modification, are involved in most cellular biological processes. Thus, abnormal regulation of epigenetics is implicated in the occurrence of various diseases, including cancer. Human MOF (males absent on the first is a member of the MYST (Moz-Ybf2/Sas3-Sas2-Tip60 family of histone acetyltransferases (HATs. As a catalytic subunit, MOF can form at least two distinct multiprotein complexes (MSL and NSL in human cells. Both complexes can acetylate histone H4 at lysine 16 (H4K16; however, the NSL complex possesses broader substrate specificity and can also acetylate histone H4 at lysines 5 and 8 (H4K5 and H4K8, suggesting the complexity of the intracellular functions of MOF. Silencing of MOF in cells leads to genomic instability, inactivation of gene transcription, defective DNA damage repair and early embryonic lethality. Unbalanced MOF expression and its corresponding acetylation of H4K16 have been found in certain primary cancer tissues, including breast cancer, medulloblastoma, ovarian cancer, renal cell carcinoma, colorectal carcinoma, gastric cancer, as well as non-small cell lung cancer. In this review, we provide a brief overview of MOF and its corresponding histone acetylation, introduce recent research findings that link MOF functions to tumorigenesis and speculate on the potential role that may be relevant to tumorigenic pathways.

  15. Elucidating Negative Thermal Expansion in MOF-5

    International Nuclear Information System (INIS)

    Multi-temperature X-ray diffraction studies show that twisting, rotation, and libration cause negative thermal expansion (NTE) of the nanoporous metal-organic framework MOF-5, Zn4O(1,4-benzenedicarboxylate)3. The near-linear lattice contraction is quantified in the temperature range 80-500 K using synchrotron powder X-ray diffraction. Vibrational motions causing the abnormal expansion behavior are evidenced by shortening of certain interatomic distances with increasing temperature according to single-crystal X-ray diffraction on a guest-free crystal over a broad temperature range. Detailed analysis of the atomic positional and displacement parameters suggests two contributions to cause the effect: (1) local twisting and vibrational motion of the carboxylate groups and (2) concerted transverse vibration of the linear linkers. The vibrational mechanism is confirmed by calculations of the dynamics in a molecular fragment of the framework.

  16. Synthesis and characterization of UiO-67-BNDC MOF

    OpenAIRE

    Wu, Lianpao

    2015-01-01

    In this study, the 1,1'-binaphthyl-4,4'-dicarboxylic acid (BNDC) linker has been synthesized by six-step synthesis route in five gram level. Meanwhile, a four-step synthesis route was also explored in a milligram scale. Then a new Zr-MOF with the BNDC linker was prepared by the conventional method. The synthesis of this MOF single crystal was also tested.This new Zr-MOF was characterized by a various methods including powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), N2 adsor...

  17. Positronium in MOFs: the Atom out of the box

    CERN Document Server

    Crivelli, P; Barbiellini, B; Brown, B L; Feldblyum, J I; Guo, P; Gidley, D W; Gerchow, L; Matzger, A J

    2013-01-01

    Recently, evidence for positronium (Ps) in a Bloch state in self-assembled metal--organic frameworks (MOFs) has been reported [Dutta et al., Phys. Rev. Lett. 110, 197403 (2013)]. In this paper, we study Ps emission into vacuum from four different MOFs crystals: MOF-5, IRMOF-8, FMA and IRMOF-20. Our measurements of Ps yield and emission energy into vacuum provide definitive evidence of Ps delocalization. We determine with a different technique Ps diffusion lengths in agreement with the recently published results. Furthermore, we measure that a fraction of the Ps is emitted into vacuum with a distinctly smaller energy than what one would expect for Ps localized in the MOFs' cells. We show that a calculation assuming Ps delocalized in a Kronig--Penney potential reproduces the measured Ps emission energy.

  18. Finely tuning MOFs towards high-performance post-combustion CO2 capture materials.

    Science.gov (United States)

    Wang, Qian; Bai, Junfeng; Lu, Zhiyong; Pan, Yi; You, Xiaozeng

    2016-01-11

    CO2 capture science and technology, particularly for the post-combustion CO2 capture, has become one of very important research fields, due to great concern of global warming. Metal-organic frameworks (MOFs) with a unique feature of structural fine-tunability, unlike the traditional porous solid materials, can provide many and powerful platforms to explore high-performance adsorbents for post-combustion CO2 capture. Until now, several strategies for finely tuning MOF structures have been developed, in which either the larger quadrupole moment and polarizability of CO2 are considered: metal ion change (I), functional groups attachment (II) and functional group insertion (III), vary the electronic nature of the pore surface; or targeting the smaller kinetic diameter of CO2 over N2 is focused on: framework interpenetration (IV), ligand shortening (V) and coordination site shifting (VI) contract the pore size of frameworks to improve their CO2 capture properties. In this review, from the viewpoint of synthetic materials scientists/chemists, we would like to introduce and summarize these strategies based upon recent work published by other groups and ourselves. PMID:26512792

  19. Multiple-photon isotope separation in MoF6

    International Nuclear Information System (INIS)

    Isotopically selective dissociation of MoF6 has been induced by irradiating low pressure samples of MoF6 with intense CO2 laser radiation. Several frequencies within the weak γ3 + γ5 combination band were employed. The isotopic selectivity was about 1% per mass unit which reflects the small isotope shifts, and the reaction yield was substantially less than for similar experiments with SF6. (Auth.)

  20. Understanding and controlling the water stability of MOF-74

    Science.gov (United States)

    Zuluaga, Sebastian; Fuentes, Erika; Tan, Kui; Xu, Feng; Li, Jing; Chabal, Yves; Thonhauser, Timo

    Metal organic framework (MOF) materials in general, and MOF-74 in particular, have promising properties for many technologically important processes. However, their instability under humid conditions severely restricts their practical use. In this work, we show that this instability and the accompanying reduction of the CO2 uptake capacity of MOF-74 under humid conditions originate in the dissociation of water molecules at the metal centers. In turn, the reduction in the CO2 uptake capacity occurs as the metal centers are occupied by the remaining OH groups after the water molecules dissociate. It follows that the reduction in CO2 uptake depends on the catalytic activity of MOF-74 towards the water dissociation reaction H2O --> OH+H. On the other hand, we show that--while the water molecules themselves do only have a negligible effect on the crystal structure of MOF-74--the OH and H products of the dissociation reaction can significantly weaken the MOF framework and lead to the observed crystal structure breakdown. With this knowledge, we can now propose a way to suppress this particular reaction and therefore control the stability of the system under humid conditions. This work was supported in full by DOE Grant No. DE-FG02-08ER46491.

  1. Processing and Performance of MOF (Metal Organic Framework)-Loaded PAN Nanofibrous Membrane for CO2 Adsorption

    Science.gov (United States)

    Wahiduzzaman; Khan, Mujibur R.; Harp, Spencer; Neumann, Jeffrey; Sultana, Quazi Nahida

    2016-04-01

    The objective of this experimental study is to produce a nanofibrous membrane functionalized with adsorbent particles called metal organic framework (MOF) in order to adsorb CO2 from a gas source. Therefore, Polyacrylonitrile (PAN) was chosen as the precursor for nanofibers and HKUST-1, a Cu-based MOF, was chosen as adsorbent. The experimental process consists of electrospinning PAN solution blended with HKUST-1 to produce a nanofibrous mat as working substrates. The fibers were collected in a cylindrical canister model. SEM image of this mat showed nanofibers with the presence of small adsorbent particles, impregnated into the as-spun fibers discretely. To increase the amount of MOF particles for effectual gas adsorption, a secondary solvothermal process of producing MOF particles on the fibers was required. This process consists of multiple growth cycles of HKUST-1 particles by using a sol-gel precursor. SEM images showed uniform distribution of porous MOF particles of 2-4 µm in size on the fiber surface. Energy dispersive spectroscopy report of the fiber confirmed the presence of MOF particles through the identification of characteristic Copper elemental peaks of HKUST-1. To determine the thermal stability of the fibrous membrane, Thermogravimetric analysis of HKUST-1 consisting of PAN fiber was performed where a total weight loss of 40% between 210 and 360 °C was observed, hence proving the high-temperature durability of the synthesized membrane. BET surface area of the fiber membrane was measured as 540.73 m2/g. The fiber membrane was then placed into an experimental test bench containing a mixed gas inflow of CO2 and N2. Using non-dispersive infrared CO2 sensors connected to the inlet and outlet port of the bench, significant reduction of CO2 in concentration was measured. Comparative IR spectroscopic analysis between the gas-treated and gas untreated fiber samples showed the presence of characteristic peak in the vicinity of 2300 and 2400 cm-1 which

  2. Synthesis of Framework Isomer MOFs Containing Zinc and 4-Tetrazolyl Benzenecarboxylic Acid via a Structure Directing Solvothermal Approach

    Directory of Open Access Journals (Sweden)

    Carlos Ordonez

    2015-04-01

    Full Text Available The solvothermal synthesis of framework isomers was carried out using the hybrid carboxylate and tetrazolate functional ligand, 4-tetrazolyl benzenecarboxylic acid (H2TBC, TBC = 4-tetrazolyl benzenecarboxylate and zinc. H2TBC was also synthesized with the solvothermal approach, and is referred herein as structure 1. Using single-crystal X-ray diffraction, we found that the tetrazolate groups of TBC show an unusual “opposite-on” coordination mode with zinc. Three previously characterized metal-organic frameworks (MOFs were obtained by systematically changing the solvents of the H2TBC-Zn reaction, (1 ZnTBC, 2, which has a non-porous structure; (2 Zn2(TBC2(H2O, 3, which has an amphiphilic pore structure and (3 Zn2(TBC2{guest}, 4, which is porous and has channels containing uncoordinated N heteroatoms. Fluorescence spectra of 4 reveal a strong blue emission mainly from the TBC ligands.

  3. Ab initio study of hydrogen adsorption in MOF-5.

    Science.gov (United States)

    Sillar, Kaido; Hofmann, Alexander; Sauer, Joachim

    2009-03-25

    Metal-organic frameworks (MOFs) are promising adsorbents for hydrogen storage. Density functional theory and second-order Møller-Plesset perturbation theory (MP2) are used to calculate the interaction energies between H(2) and individual structural elements of the MOF-5 framework. The strongest interaction, DeltaH(77) = -7.1 kJ/mol, is found for the alpha-site of the OZn(4)(O(2)Ph)(6) nodes. We show that dispersion interactions and zero-point vibrational energies must be taken into account. Comparison of calculations done under periodic boundary conditions for the complete structure with those done for finite models cut from the MOF-5 framework shows that the interactions with H(2) originate mainly from the local environment around the adsorption site. When used within a Multi-Langmuir model, the MP2 results reproduce measured adsorption isotherms (the predicted amount is 6 wt % at 77 K and 40 bar) if we assume that the H(2) molecules preserve their rotational degrees of freedom in the adsorbed state. This allows to discriminate between different isotherms measured for different MOF-5 samples and to reliably predict isotherms for new MOF structures. PMID:19253977

  4. A novel 3D energetic MOF of high energy content: synthesis and superior explosive performance of a Pb(ii) compound with 5,5'-bistetrazole-1,1'-diolate.

    Science.gov (United States)

    Shang, Yu; Jin, Bo; Peng, Rufang; Liu, Qiangqiang; Tan, Bisheng; Guo, Zhicheng; Zhao, Jun; Zhang, Qingchun

    2016-09-21

    The development of high-performance insensitive energetic materials is important because of the increasing demand for these materials in military and civilian applications. A novel 3D energetic metal-organic framework (MOF) of exceptionally high energy content, [Pb(BTO)(H2O)]n, was synthesized and structurally characterized by single crystal X-ray diffraction, featuring a three-dimensional parallelogram porous framework, where BTO represents 5,5'-bistetrazole-1,1'-diolate. The thermal stability and energetic properties were determined, exhibiting good thermostability (Td = 309.0 °C), excellent detonation pressure (P) of 53.06 GPa, a detonation velocity (D) of 9.204 km s(-1), and acceptable sensitivity to confirmed impact (IS = 7.5 J). Notably, the complex possesses unprecedented superior density than the reported energetic MOFs. The results highlight this new MOF as a potential energetic material. PMID:27518537

  5. File list: Oth.ALL.50.mof.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.mof.AllCell dm3 TFs and others mof All cell types SRX146999,ERX101806,ER...X101804,SRX287892,SRX146998,SRX287891 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.50.mof.AllCell.bed ...

  6. Loading of Two Related Metal-Organic Frameworks (MOFs, [Cu2(bdc2(dabco] and [Cu2(ndc2(dabco], with Ferrocene

    Directory of Open Access Journals (Sweden)

    Wolfgang Wenzel

    2011-09-01

    Full Text Available We have studied the loading of two related, similar porous metal-organic frameworks (MOFs [Cu2(bdc2(dabco] (1, and [Cu2(ndc2(dabco] (2 with ferrocene by exposing bulk powder samples to the corresponding vapor. On the basis of powder X-ray diffraction data and molecular dynamics (MD calculations we propose that each pore can store one ferrocene molecule. Despite the rather pronounced similarity of the two MOFs a quite different behavior is observed, for 1 loading with ferrocene leads to an anisotropic 1% contraction, whereas for 2 no deformation is observed. Mössbauer spectroscopy studies reveal that the Fe oxidation level remains unchanged during the process. Time dependent studies reveal that the diffusion constant governing the loading from the gas-phase for 1 is approximately three times larger than the value for 2.

  7. 2-periodic metal-organic frameworks (MOFs) as supermolecular building layers (SBLs) for making targeted 3-periodic MOFs

    KAUST Repository

    Eddaoudi, Mohamed

    2015-09-22

    Embodiments of the present disclosure provide for chemical assemblies, multidimensional metal-organic frameworks (MOFs), supermolecular building layers (SBLs), inorganic molecular building blocks (MBBs), organic MBBs (designed ligands), methods of making each, and methods of using each, and the like. In an embodiment, the composition can be used in catalysis, separations, gas storage, and drug delivery.

  8. Synthesis and CO2 adsorption study of modified MOF-5 with multi-wall carbon nanotubes and expandable graphite

    International Nuclear Information System (INIS)

    MOF-5 was synthesized by solvothermal method and its reactivation under anhydrous conditions. This research is conducted to investigate the effect of MOF-5 and MOF-5 modified with multi-wall carbon nanotubes (MWCNTs) and expandable graphite (EG) on the performance of CO2 adsorption. The synthesized MOFs were characterized using Field emission scanning electron microscopy (FESEM) for surface morphology, Thermogravimetric analysis (TGA) for thermal stability, X-ray diffraction (XRD) for crystals plane, Brunauer-Emmet-Teller (BET) for surface area and CO2 adsorption. The result had showed that the modified MOF-5 enhanced the CO2 adsorption compared to the pure MOF-5. The increment in the CO2 uptake capacities of MOF materials was attributed to the decrease in the pore size and enhancement of micropore volume of MOF-5 by multi-walled carbon nanotube and EG incorporation. The BET surface area of the synthesized MOF-5@MWCNTs is more than MOF-5. The CO2 sorption capacities of MOF-5 and MOF-5@MWCNTs were observed to increase from 0.00008 to 0.00048 mol g-1 at 298 K and 1 bar. The modified MOF-5@MWCNTs resulted in the highest CO2 adsorption followed by the modified MOF-5@ EG and lastly, MOF-5

  9. In situ solvothermal growth of metal-organic framework-5 supported on porous copper foam for noninvasive sampling of plant volatile sulfides.

    Science.gov (United States)

    Hu, Yuling; Lian, Haixian; Zhou, Langjun; Li, Gongke

    2015-01-01

    The present study reported on an in situ solvothermal growth method for immobilization of metal-organic framework MOF-5 on porous copper foam support for enrichment of plant volatile sulfides. The porous copper support impregnated with mother liquor of MOF-5 anchors the nucleation and growth of MOF crystallites at its surface, and its architecture of the three-dimensional channel enables accommodation of the MOF-5 crystallite seed. A continuous and well-intergrown MOF-5 layer, evidenced from scanning electron microscope imaging and X-ray diffraction, was successfully immobilized on the porous metal bar with good adhesion and high stability. Results show that the resultant MOF-5 coating was thermally stable up to 420 °C and robust enough for replicate extraction for at least 200 times. The MOF-5 bar was then applied to the headspace sorptive extraction of the volatile organic sulfur compounds in Chinese chive and garlic sprout in combination with thermal desorption-gas chromatography/mass spectrometry. It showed high extraction sensitivity and good selectivity to these plant volatile sulfides owing to the extraordinary porosity of the metal-organic framework as well as the interaction between the S-donor sites and the surface cations at the crystal edges. Several primary sulfur volatiles containing allyl methyl sulfide, dimethyl disulfide, diallyl sulfide, methyl allyl disulfide, and diallyl disulfide were quantified. Their limits of detection were found to be in the range of 0.2-1.7 μg/L. The organic sulfides were detected in the range of 6.0-23.8 μg/g with recoveries of 76.6-100.2% in Chinese chive and 11.4-54.6 μg/g with recoveries of 77.1-99.8% in garlic sprout. The results indicate the immobilization of MOF-5 on copper foam provides an efficient enrichment formats for noninvasive sampling of plant volatiles. PMID:25435245

  10. MOFs for storage of natural gas in mobile applications

    Energy Technology Data Exchange (ETDEWEB)

    Marx, S.; Arnold, L.; Gaab, M.; Maurer, S.; Weickert, M.; Mueller, U. [BASF SE, Ludwigshafen (Germany); Gummaraju, R.; SantaMaria, M.; Wilson, K.; Garbotz, C.; Lynch, J. [BASF Corporation, Iselin, NJ (United States)

    2013-11-01

    Metal-organic frameworks (MOFs) are supposed to have high potential in gas storage, particular in the storage of natural gas (NG) for mobile applications. Due to the shale gas exploration and the cost advantage of natural gas on the North American market as well as the environmental benign behavior upon combustion, storage of gaseous fuels will become more important for future mobility. The main challenge with all gaseous fuels is the limited range of the fuel stored on board of a vehicle. Instead of increasing the pressure in the tank, which would lead to heavy tanks and high compression costs, MOFs might help to improve the energy density of the gas stored in a tank resulting in an increased driving distance or reduced space needed for the gas tanks. (orig.)

  11. Application of MD Simulations to Predict Membrane Properties of MOFs

    OpenAIRE

    Elda Adatoz; Seda Keskin

    2015-01-01

    Research Article Application of MD Simulations to Predict Membrane Properties of MOFs Elda Adatoz and Seda Keskin Chemical and Biological Engineering, Koc University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey Correspondence should be addressed to Seda Keskin; Received 22 May 2015; Accepted 13 July 2015 Academic Editor: Yanlin Song Copyright © 2015 E. Adatoz and S. Keskin. This is an open access article distributed under the Creative Commons A...

  12. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

    KAUST Repository

    Sapsanis, Christos

    2015-07-24

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

  13. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study.

    Science.gov (United States)

    Sapsanis, Christos; Omran, Hesham; Chernikova, Valeriya; Shekhah, Osama; Belmabkhout, Youssef; Buttner, Ulrich; Eddaoudi, Mohamed; Salama, Khaled N

    2015-01-01

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance. PMID:26213943

  14. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

    Directory of Open Access Journals (Sweden)

    Christos Sapsanis

    2015-07-01

    Full Text Available A prototypical metal-organic framework (MOF, a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc ligands (Cu(bdc·xH2O, was grown successfully as a thin film on interdigitated electrodes (IDEs. IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs. Accordingly, the resultant IDEs coated with the Cu(bdc·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

  15. Synthesis and characterization of MOF-aminated graphite oxide composites for CO2 capture

    International Nuclear Information System (INIS)

    A kind of metal-organic frameworks (MOF-5) and aminated graphite oxide (AGO) composites were prepared for CO2 capture to mitigate global warming. MOF-5, MOF-5/GO (composite of MOF-5 and graphite oxide) and MOF-5/AGO samples were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscope (SEM), nitrogen adsorption as well as thermogravimetric analysis to figure out their chemistry and structure information. Three types of samples with suitable specific surface area and pore diameter were chosen to test CO2 adsorption performance and stability under humidity conditions. The results indicate that high surface area and pore volume, pore similar in size to the size of gas adsorbate, and extra reactive sites modified in the composites contributes to the high CO2 capacity. Besides, the composites involved by GO or AGO show better anti-moisture performance than the parent MOF.

  16. Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

    Science.gov (United States)

    Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

    2016-06-01

    Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials. PMID:27061210

  17. Regulation of the histone acetyltransferase activity of hMOF via autoacetylation of Lys274

    Institute of Scientific and Technical Information of China (English)

    Bingfa Sun; Shunling Guo; Qingyu Tang; Chen Li; Rong Zeng; Zhiqi Xiong; Chen Zhong; Jianping Ding

    2011-01-01

    Dear Editor, Males-absent-on-the-first (MOF, also called MYST1 or KAT8) is a histone acetyltransferase (HAT) belonging to the MOZ, Ybf2/Sas3, Sas2 and Tip60 (MYST) family.MOF has been shown to possess a specific HAT activity towards Lysl6 of histone H4 (H4K16) [1].Homozygous knockout of MOF in mice results in loss of H4K16 acetylation and embryonic lethality, indicating that MOF and H4K16 acetylation are essential for embryogenesis and genome stability in mammals [2].Downregulation of human MOF (hMOF) leads to dramatic nuclear morphological deformation and inhibition of cell cycle progression [3], and has recently been correlated with primary breast carcinoma and medulloblastoma [4].

  18. Structure distortion of Zn4O13C24H12 framework (MOF-5)

    International Nuclear Information System (INIS)

    Zn4O13C24H12 framework (MOF-5) can occupy either cubic or tetragonal structure. It was recognized that the tetragonal MOF-5 was a distorted cubic MOF-5 caused by filling effect of ZnO or solvent. However, herein, it was found that the ZnO and solvent inside the pores of the framework did not cause the distortion of cubic MOF-5. Furthermore, the distortion is strongly dependent on the solvent vacuumed to dry the framework. If the vacuumed solvent was dimethylformamide (DMF), the crystal structure of MOF-5 was tetragonal. In contrast, if DMF was displaced by CH2Cl2 before the vacuum, the obtained MOF-5 occupied a perfect cubic structure. The thermal decomposition of cubic and tetragonal MOF-5s produced the same products: CO2, benzene, amorphous carbon, and crystal ZnO. However, the thermal decomposition of cubic MOF-5 requires a higher temperature than the tetragonal one, indicating that cubic MOF-5 is more stable than the tetragonal one.

  19. Electron attachment to MoF6, ReF6, and WF6; reaction of MoF6- with ReF6 and reaction of Ar+ with MoF6

    International Nuclear Information System (INIS)

    Rate constants were measured for electron attachment to MoF6, ReF6, and WF6 in 133 Pa of helium gas using a flowing-afterglow Langmuir-probe apparatus. The experiment is a thorny one because the molecules tend to form oxide impurities on feedline surfaces and because of thermal decomposition of MoF6 on surfaces as the gas temperature is increased. The electron attachment rate constant for MoF6 is (2.3±0.8)x10-9 cm3 s-1 at 297 K; only MoF6- is formed in the temperature range of 297-385 K. The rate constant increases with temperature up to the point where decomposition becomes apparent. Electron attachment to ReF6 occurs with a rate constant of (2.4±0.8)x10-9 cm3 s-1 at 297 K; only ReF6- is produced. MoF6- reacts with ReF6 to form ReF6- on essentially every collision, showing definitively that the electron affinity of ReF6 is greater than that of MoF6. A rate constant of (5.0±1.3)x10-10 cm3 s-1 was measured for this ion-molecule reaction at 304 K. The reverse reaction is not observed. The reaction of Ar+ with MoF6 was found to produce MoF5++F, with a rate constant of (1.8±0.5)x10-9 cm3 s-1. WF6 attaches electrons so slowly at room temperature that the attachment rate was below detection level (≤10-12 cm3 s-1). By 552 K, the attachment rate constant reaches a value of (2±1)x10-10 cm3 s-1

  20. Robust, chiral, and porous BINAP-based metal-organic frameworks for highly enantioselective cyclization reactions.

    Science.gov (United States)

    Sawano, Takahiro; Thacker, Nathan C; Lin, Zekai; McIsaac, Alexandra R; Lin, Wenbin

    2015-09-30

    We report here the design of BINAP-based metal-organic frameworks and their postsynthetic metalation with Rh complexes to afford highly active and enantioselective single-site solid catalysts for the asymmetric cyclization reactions of 1,6-enynes. Robust, chiral, and porous Zr-MOFs of UiO topology, BINAP-MOF (I) or BINAP-dMOF (II), were prepared using purely BINAP-derived dicarboxylate linkers or by mixing BINAP-derived linkers with unfunctionalized dicarboxylate linkers, respectively. Upon metalation with Rh(nbd)2BF4 and [Rh(nbd)Cl]2/AgSbF6, the MOF precatalysts I·Rh(BF4) and I·Rh(SbF6) efficiently catalyzed highly enantioselective (up to 99% ee) reductive cyclization and Alder-ene cycloisomerization of 1,6-enynes, respectively. I·Rh catalysts afforded cyclization products at comparable enantiomeric excesses (ee's) and 4-7 times higher catalytic activity than the homogeneous controls, likely a result of catalytic site isolation in the MOF which prevents bimolecular catalyst deactivation pathways. However, I·Rh is inactive in the more sterically encumbered Pauson-Khand reactions between 1,6-enynes and carbon monoxide. In contrast, with a more open structure, Rh-functionalized BINAP-dMOF, II·Rh, effectively catalyzed Pauson-Khand cyclization reactions between 1,6-enynes and carbon monoxide at 10 times higher activity than the homogeneous control. II·Rh was readily recovered and used three times in Pauson-Khand cyclization reactions without deterioration of yields or ee's. Our work has expanded the scope of MOF-catalyzed asymmetric reactions and showed that the mixed linker strategy can effectively enlarge the open space around the catalytic active site to accommodate highly sterically demanding polycyclic metallocycle transition states/intermediates in asymmetric intramolecular cyclization reactions. PMID:26335305

  1. Robust, Chiral, and Porous BINAP-Based Metal–Organic Frameworks for Highly Enantioselective Cyclization Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sawano, Takahiro; Thacker, Nathan C.; Lin, Zekai; McIsaac, Alexandra R.; Lin, Wenbin (UC)

    2016-05-06

    We report here the design of BINAP-based metal–organic frameworks and their postsynthetic metalation with Rh complexes to afford highly active and enantioselective single-site solid catalysts for the asymmetric cyclization reactions of 1,6-enynes. Robust, chiral, and porous Zr-MOFs of UiO topology, BINAP-MOF (I) or BINAP-dMOF (II), were prepared using purely BINAP-derived dicarboxylate linkers or by mixing BINAP-derived linkers with unfunctionalized dicarboxylate linkers, respectively. Upon metalation with Rh(nbd)2BF4 and [Rh(nbd)Cl]2/AgSbF6, the MOF precatalysts I·Rh(BF4) and I·Rh(SbF6) efficiently catalyzed highly enantioselective (up to 99% ee) reductive cyclization and Alder-ene cycloisomerization of 1,6-enynes, respectively. I·Rh catalysts afforded cyclization products at comparable enantiomeric excesses (ee’s) and 4–7 times higher catalytic activity than the homogeneous controls, likely a result of catalytic site isolation in the MOF which prevents bimolecular catalyst deactivation pathways. However, I·Rh is inactive in the more sterically encumbered Pauson–Khand reactions between 1,6-enynes and carbon monoxide. In contrast, with a more open structure, Rh-functionalized BINAP-dMOF, II·Rh, effectively catalyzed Pauson–Khand cyclization reactions between 1,6-enynes and carbon monoxide at 10 times higher activity than the homogeneous control. II·Rh was readily recovered and used three times in Pauson–Khand cyclization reactions without deterioration of yields or ee’s. Our work has expanded the scope of MOF-catalyzed asymmetric reactions and showed that the mixed linker strategy can effectively enlarge the open space around the catalytic active site to accommodate highly sterically demanding polycyclic metallocycle transition states/intermediates in asymmetric intramolecular cyclization reactions.

  2. Metal-Organic Frameworks (MOFs) as Sandwich Coating Cushion for Silicon Anode in Lithium Ion Batteries.

    Science.gov (United States)

    Han, Yuzhen; Qi, Pengfei; Zhou, Junwen; Feng, Xiao; Li, Siwu; Fu, Xiaotao; Zhao, Jingshu; Yu, Danni; Wang, Bo

    2015-12-01

    A novel metal-organic framework (MOF) sandwich coating method (denoted as MOF-SC) is developed for hybrid Li ion battery electrode preparation, in which the MOF films are casted on the surface of a silicon layer and sandwiched between the active silicon and the separator. The obtained electrodes show improved cycling performance. The areal capacity of the cheap and readily available microsized Si treated with MOF-SC can reach 1700 μAh cm(-2) at 265 μA cm(-2) and maintain at 850 μAh cm(-2) after 50 cycles. Beyond the above, the commercial nanosized Si treated by MOF-SC also shows greatly enhanced areal capacity and outstanding cycle stability, 600 μAh cm(-2) for 100 cycles without any apparent fading. By virtue of the novel structure prepared by the MOFs, this new MOF-SC structure serves as an efficient protection cushion for the drastic volume change of silicon during charge/discharge cycles. Furthermore, this MOF layer, with large pore volume and high surface area, can adsorb electrolyte and allow faster diffusion of Li(+) as evidenced by decreased impedance and improved rate performance. PMID:26569374

  3. Direct observations of the MOF (UiO-66) structure by transmission electron microscopy

    KAUST Repository

    Zhu, Liangkui

    2013-01-01

    As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure was determined and further confirmed by Rietveld refinements of powder X-ray diffraction. HRTEM gave direct imaging of the channels. © 2013 The Royal Society of Chemistry.

  4. Computational Screening of MOF-Based Mixed Matrix Membranes for CO2/N2 Separations

    Directory of Open Access Journals (Sweden)

    Zeynep Sumer

    2016-01-01

    Full Text Available Atomically detailed simulations were used to examine CO2/N2 separation potential of metal organic framework- (MOF- based mixed matrix membranes (MMMs in this study. Gas permeability and selectivity of 700 new MMMs composed of 70 different MOFs and 10 different polymers were calculated for CO2/N2 separation. This is the largest number of MOF-based MMMs for which computational screening is done to date. Selecting the appropriate MOFs as filler particles in polymers resulted in MMMs that have higher CO2/N2 selectivities and higher CO2 permeabilities compared to pure polymer membranes. We showed that, for polymers that have low CO2 permeabilities but high CO2 selectivities, the identity of the MOF used as filler is not important. All MOFs enhanced the CO2 permeabilities of this type of polymers without changing their selectivities. Several MOF-based MMMs were identified to exceed the upper bound established for polymers. The methods we introduced in this study will create many opportunities to select the MOF/polymer combinations with useful properties for CO2 separation applications.

  5. Exceptionally water stable heterometallic gyroidal MOFs: tuning the porosity and hydrophobicity by doping metal ions.

    Science.gov (United States)

    Zhu, Xiao-Wei; Zhou, Xiao-Ping; Li, Dan

    2016-05-01

    A strategy to improve the framework porosity and hydrophobicity of the pore surface by doping metal ions (Cu(2+), Cd(2+), or Fe(2+)) into a gyroidal MOF STU-1 has been developed. It is found that the obtained heterometallic MOFs are exceptionally water stable. PMID:27094095

  6. Mof-Tree: A Spatial Access Method To Manipulate Multiple Overlapping Features.

    Science.gov (United States)

    Manolopoulos, Yannis; Nardelli, Enrico; Papadopoulos, Apostolos; Proietti, Guido

    1997-01-01

    Investigates the manipulation of large sets of two-dimensional data representing multiple overlapping features, and presents a new access method, the MOF-tree. Analyzes storage requirements and time with respect to window query operations involving multiple features. Examines both the pointer-based and pointerless MOF-tree representations.…

  7. Effective Thermal Conductivity of MOF-5 Powder under a Hydrogen Atmosphere

    Directory of Open Access Journals (Sweden)

    Hui Wang

    2015-11-01

    Full Text Available Effective thermal conductivity is an important thermophysical property in the design of metal-organic framework-5 (MOF-5-based hydrogen storage tanks. A modified thermal conductivity model is built by coupling a theoretical model with the grand canonical Monte Carlo simulation (GCMC to predict the effect of the H2 adsorption process on the effective thermal conductivity of a MOF-5 powder bed at pressures ranging from 0.01 MPa to 50 MPa and temperatures ranging from 273.15 K to 368.15 K. Results show that the mean pore diameter of the MOF-5 crystal decreases with an increase in pressure and increases with an increase in temperature. The thermal conductivity of the adsorbed H2 increases with an increased amount of H2 adsorption. The effective thermal conductivity of the MOF-5 crystal is significantly enhanced by the H2 adsorption at high pressure and low temperature. The effective thermal conductivity of the MOF-5 powder bed increases with an increase in pressure and remains nearly unchanged with an increase in temperature. The thermal conductivity of the MOF-5 powder bed increases linearly with the decreased porosity and increased thermal conductivity of the skeleton of the MOF-5 crystal. The variation in the effective thermal conductivities of the MOF-5 crystals and bed mainly results from the thermal conductivities of the gaseous and adsorption phases.

  8. Theoretical study on the adsorption of carbon dioxide on individual and alkali-metal doped MOF-5s

    Science.gov (United States)

    Ha, Nguyen Thi Thu; Lefedova, O. V.; Ha, Nguyen Ngoc

    2016-01-01

    Density functional theory (DFT) calculations were performed to investigate the adsorption of carbon dioxide (CO2) on metal-organic framework (MOF-5) and alkali-metal (Li, K, Na) doped MOF-5s. The adsorption energy calculation showed that metal atom adsorption is exothermic in MOF-5 system. Moreover, alkali-metal doping can significantly improve the adsorption ability of carbon dioxide on MOF-5. The best influence is observed for Li-doping.

  9. An In Situ One-Pot Synthetic Approach towards Multivariate Zirconium MOFs.

    Science.gov (United States)

    Sun, Yujia; Sun, Lixian; Feng, Dawei; Zhou, Hong-Cai

    2016-05-23

    Chemically highly stable MOFs incorporating multiple functionalities are of great interest for applications under harsh environments. Herein, we presented a facile one-pot synthetic strategy to incorporate multiple functionalities into stable Zr-MOFs from mixed ligands of different geometry and connectivity. Via our strategy, tetratopic tetrakis(4-carboxyphenyl)porphyrin (TCPP) ligands were successfully integrated into UiO-66 while maintaining the crystal structure, morphology, and ultrahigh chemical stability of UiO-66. The amount of incorporated TCPP is controllable. Through various combinations of BDC derivatives and TCPP, 49 MOFs with multiple functionalities were obtained. Among them, MOFs modified with FeTCPPCl were demonstrated to be catalytically active for the oxidation of ABTS. We anticipate our strategy to provide a facile route to introduce multiple functionalities into stable Zr-MOFs for a wide variety of potential applications. PMID:27100570

  10. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    International Nuclear Information System (INIS)

    Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF) precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N2 adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO2 adsorption at room temperature

  11. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    Directory of Open Access Journals (Sweden)

    Anindita Chakraborty

    2014-12-01

    Full Text Available Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N2 adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO2 adsorption at room temperature.

  12. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Anindita; Maji, Tapas Kumar, E-mail: tmaji@jncasr.ac.in [Molecular Materials Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064 (India)

    2014-12-01

    Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF) precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N{sub 2} adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO{sub 2} adsorption at room temperature.

  13. Forming MOFs into spheres by use of molecular gastronomy methods.

    Science.gov (United States)

    Spjelkavik, Aud I; Aarti; Divekar, Swapnil; Didriksen, Terje; Blom, Richard

    2014-07-14

    A novel method utilizing hydrocolloids to prepare nicely shaped spheres of metal-organic frameworks (MOFs) has been developed. Microcrystalline CPO-27-Ni particles are dispersed in either alginate or chitosan solutions, which are added dropwise to solutions containing, respectively, either divalent group 2 cations or base that act as gelling agents. Well-shaped spheres are immediately formed, which can be dried into spheres containing mainly MOF (>95 wt %). The spheronizing procedures have been optimized with respect to maximum specific surface area, shape, and particle density of the final sphere. At optimal conditions, well-shaped 2.5-3.5 mm diameter CPO-27-Ni spheres with weight-specific surface areas <10 % lower than the nonformulated CPO-27-Ni precursor, and having sphere densities in the range 0.8 to 0.9 g cm(-3) and particle crushing strengths above 20 N, can be obtained. The spheres are well suited for use in fixed-bed catalytic or adsorption processes. PMID:24964774

  14. MOFs under pressure: the reversible compression of a single crystal.

    Science.gov (United States)

    Gagnon, Kevin J; Beavers, Christine M; Clearfield, Abraham

    2013-01-30

    The structural change and resilience of a single crystal of a metal-organic framework (MOF), Zn(HO(3)PC(4)H(8)PO(3)H)·2H(2)O (ZAG-4), was investigated under high pressures (0-9.9 GPa) using in situ single crystal X-ray diffraction. Although the unit cell volume decreases over 27%, the quality of the single crystal is retained and the unit cell parameters revert to their original values after pressure has been removed. This framework is considerably compressible with a bulk modulus calculated at ∼11.7 GPa. The b-axis also exhibits both positive and negative linear compressibility. Within the applied pressures investigated, there was no discernible failure or amorphization point for this compound. The alkyl chains in the structure provide a spring-like cushion to stabilize the compression of the system allowing for large distortions in the metal coordination environment, without destruction of the material. This intriguing observation only adds to the current speculation as to whether or not MOFs may find a role as a new class of piezofunctional solid-state materials for application as highly sensitive pressure sensors, shock absorbing materials, pressure switches, or smart body armor. PMID:23320490

  15. Metal-organic and zeolite imidazolate frameworks (MOFs and ZIFs) for highly selective separations

    Energy Technology Data Exchange (ETDEWEB)

    Yaghi, Omar M

    2012-09-17

    Metal-organic and zeolite imidazolate frameworks (MOFs and ZIFs) have been investigated for the realization as separation media with high selectivity. These structures are held together with strong bonds, making them architecturally, chemically, and thermally stable. Therefore, employing well designed building units, it is possible to discover promising materials for gas and vapor separation. This grant was focused on the study of MOFs and ZIFs with these specific objectives: (i) to develop a strategy for producing MOFs and ZIFs that combine high surface areas with active sites for their use in gas adsorption and separation of small organic compounds, (ii) to introduce active sites in the framework by a post-synthetic modification and metalation of MOFs and ZIFs, and (iii) to design and synthesize MOFs with extremely high surface areas and large pore volumes to accommodate large amounts of guest molecules. By the systematic study, this effort demonstrated how to introduce active functional groups in the frameworks, and this is also the origin of a new strategy, which is termed isoreticular functionalization and metalation. However, a large pore volume is still a prerequisite feature. One of the solutions to overcome this challenge is an isoreticular expansion of a MOF's structure. With triangular organic linker and square building units, we demonstrated that MOF-399 has a unit cell volume 17 times larger than that of the first reported material isoreticular to it, and it has the highest porosity (94%) and lowest density (0.126 g cm-3) of any MOF reported to date. MOFs are not just low density materials; the guest-free form of MOF-210 demonstrates an ultrahigh porosity, whose BET surface area was estimated to be 6240 m2 g-1 by N2 adsorption measurements.

  16. Drosophila MOF controls Checkpoint protein2 and regulates genomic stability during early embryogenesis

    Directory of Open Access Journals (Sweden)

    Pushpavalli Sreerangam NCVL

    2013-01-01

    Full Text Available Abstract Background In Drosophila embryos, checkpoints maintain genome stability by delaying cell cycle progression that allows time for damage repair or to complete DNA synthesis. Drosophila MOF, a member of MYST histone acetyl transferase is an essential component of male X hyperactivation process. Until recently its involvement in G2/M cell cycle arrest and defects in ionizing radiation induced DNA damage pathways was not well established. Results Drosophila MOF is highly expressed during early embryogenesis. In the present study we show that haplo-insufficiency of maternal MOF leads to spontaneous mitotic defects like mitotic asynchrony, mitotic catastrophe and chromatid bridges in the syncytial embryos. Such abnormal nuclei are eliminated and digested in the yolk tissues by nuclear fall out mechanism. MOF negatively regulates Drosophila checkpoint kinase 2 tumor suppressor homologue. In response to DNA damage the checkpoint gene Chk2 (Drosophila mnk is activated in the mof mutants, there by causing centrosomal inactivation suggesting its role in response to genotoxic stress. A drastic decrease in the fall out nuclei in the syncytial embryos derived from mof1/+; mnkp6/+ females further confirms the role of DNA damage response gene Chk2 to ensure the removal of abnormal nuclei from the embryonic precursor pool and maintain genome stability. The fact that mof mutants undergo DNA damage has been further elucidated by the increased number of single and double stranded DNA breaks. Conclusion mof mutants exhibited genomic instability as evidenced by the occurance of frequent mitotic bridges in anaphase, asynchronous nuclear divisions, disruption of cytoskeleton, inactivation of centrosomes finally leading to DNA damage. Our findings are consistent to what has been reported earlier in mammals that; reduced levels of MOF resulted in increased genomic instability while total loss resulted in lethality. The study can be further extended using

  17. Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

    International Nuclear Information System (INIS)

    A novel metal organic framework (MOF) formulated as [Eu(H2O)2(fdc)(ox)0.5·(H2O)]n (1, fdc2−=2,5-furandicarboxylate, ox2−=oxalate), was hydrothermally synthesized via in situ ox2− generation from the partial decomposition of the fdc2− ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H2O, ox2−and fdc2−) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu3+ red emission and the differences observed reflects the slightly different structures of these polymorphs. - Graphical abstract: Exploring metal organic framework polymorphism in the system Eu(H2O)2(fdc)(ox)0.5·(H2O)]n (fdc2−=2,5-furandicarboxylate, ox2−=oxalate) for tuning light emission. Display Omitted - Highlights: • Synthesis of Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOF polymorphs. • Detailed single-crystal study of polymorphs including hydrogen-bonding networks. • Photoluminescence spectroscopy show subtle differences light emission properties

  18. Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Fa-Nian, E-mail: fshi@ua.pt; Ananias, Duarte; Yang, Ting-Hai; Rocha, João, E-mail: rocha@ua.pt

    2013-08-15

    A novel metal organic framework (MOF) formulated as [Eu(H{sub 2}O){sub 2}(fdc)(ox){sub 0.5}·(H{sub 2}O)]{sub n} (1, fdc{sup 2−}=2,5-furandicarboxylate, ox{sup 2−}=oxalate), was hydrothermally synthesized via in situ ox{sup 2−} generation from the partial decomposition of the fdc{sup 2−} ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H{sub 2}O, ox{sup 2−}and fdc{sup 2−}) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu{sup 3+} red emission and the differences observed reflects the slightly different structures of these polymorphs. - Graphical abstract: Exploring metal organic framework polymorphism in the system Eu(H{sub 2}O){sub 2}(fdc)(ox){sub 0.5}·(H{sub 2}O)]{sub n} (fdc{sup 2−}=2,5-furandicarboxylate, ox{sup 2−}=oxalate) for tuning light emission. Display Omitted - Highlights: • Synthesis of Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOF polymorphs. • Detailed single-crystal study of polymorphs including hydrogen-bonding networks. • Photoluminescence spectroscopy show subtle differences light emission properties.

  19. Understanding the H 2 Sorption Trends in the M-MOF-74 Series (M = Mg, Ni, Co, Zn)

    KAUST Repository

    Pham, Tony

    2015-01-15

    © 2014 American Chemical Society. Electronic structure calculations and simulations of H2 sorption were performed in four members of the M-MOF-74 series: Mg-MOF-74, Ni-MOF-74, Co-MOF-74, and Zn-MOF-74. Notable differences were observed in the partial charge and polarizability of the metal ions derived from the electronic structure calculations. The modeling parameters obtained from the electronic structure calculations were found to influence certain features in the experimentally observed H2 sorption trends in the M-MOF-74 series. The simulations were performed with the inclusion of explicit many-body polarization, which was required to reproduce the experimental H2 sorption observables (i.e., sorption isotherms and isosteric heats of adsorption (Qst)) and the H2-metal interaction in all four MOFs using classical molecular simulation. Consistent with experimental measurements, the simulations captured the following trend for the H2-metal interaction strength: Ni-MOF-74 > Co-MOF-74 > Mg-MOF-74 > Zn-MOF-74. The calculations revealed that stronger H2-metal interactions within the M-MOF-74 series corresponded to shorter H2-metal distances and higher induced dipoles on the metal-sorbed H2 molecules. In addition, it was observed that there was a strong correlation between the H2-metal interaction and the polarization contribution. Although Mg-MOF-74 has the highest calculated partial charge for the metal ion within the series, the Mg2+ ion has a very low polarizability compared to the other M2+ ions; this explains why the H2-metal interaction in this MOF is weaker compared to those for Ni-MOF-74 and Co-MOF-74. The sterics interactions, reflected in the crystal structure for all four MOFs, also played a role for the observed H2 sorption trends. Zn-MOF-74 has the lowest H2 uptakes and Qst within the series due to an unfavorable geometric environment for the Zn2+ ions within the ZnO5 clusters. Lastly, the two-dimensional quantum rotational levels were calculated for the H

  20. Partitioning MOF-5 into Confined and Hydrophobic Compartments for Carbon Capture under Humid Conditions.

    Science.gov (United States)

    Ding, Nan; Li, Haiwei; Feng, Xiao; Wang, Qianyou; Wang, Shan; Ma, Li; Zhou, Junwen; Wang, Bo

    2016-08-17

    Metal-organic frameworks (MOFs), by virtue of their remarkable uptake capability, selectivity, and ease of regeneration, hold great promise for carbon capture from fossil fuel combustion. However, their stability toward moisture together with the competitive adsorption of water against CO2 drastically dampens their capacity and selectivity under real humid flue gas conditions. In this work, an effective strategy was developed to tackle the above obstacles by partitioning the channels of MOFs into confined, hydrophobic compartments by in situ polymerization of aromatic acetylenes. Specifically, polynaphthylene was formed via a radical reaction inside the channels of MOF-5 and served as partitions without altering the underlying structure of the framework. Compared with pristine MOF-5, the resultant material (PN@MOF-5) exhibits a doubled CO2 capacity (78 vs 38 cm(3)/g at 273 K and 1 bar), 23 times higher CO2/N2 selectivity (212 vs 9), and significantly improved moisture stability. The dynamic CO2 adsorption capacity can be largely maintained (>90%) under humid conditions during cycles. This strategy can be applied to other MOF materials and may shed light on the design of new MOF-polymer materials with tunable pore sizes and environments to promote their practical applications. PMID:27477091

  1. A Review on Breathing Behaviors of Metal-Organic-Frameworks (MOFs for Gas Adsorption

    Directory of Open Access Journals (Sweden)

    Mays Alhamami

    2014-04-01

    Full Text Available Metal-organic frameworks (MOFs are a new class of microporous materials that possess framework flexibility, large surface areas, “tailor-made” framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses.

  2. Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2015-10-01

    Full Text Available As a new branch of MOFs which are composed of biocompatible metal ions and organic ligands, bio-metal-organic frameworks (bio-MOFs have attracted much attention recently. Bio-MOFs feature multiple Lewis basic sites which have strong interaction with CO2 molecules, thus they have great potential in the separation and purification of gas mixtures containing CO2. In this work, molecular simulation studies were carried out to investigate the adsorption and diffusion behaviors of CO2/N2 gas mixtures in bio-MOF-11. Results show that bio-MOF-11 displays excellent adsorption selectivity towards CO2 in CO2/N2 gas mixtures which was dominated by electrostatic interaction between material and CO2. In addition, we found both CO2 and N2 molecules were preferably adsorbed around the pyrimidine ring and exocyclic amino and transferred to the secondary favorable adsorption sites (methyl groups with increasing pressure. Bio-MOF-11 membranes show superior permeation selectivity, but low permeability for CO2/N2 gas systems. The reason is that the small pores restrict the movement of gas molecules, leading to the observed low permeability. The information obtained in this work can be applied to other theoretical and experimental studies of bio-MOFs adsorbents and membranes in the future.

  3. Nanoscale Synthesis of Two Porphyrin-Based MOFs with Gallium and Indium.

    Science.gov (United States)

    Rhauderwiek, Timo; Waitschat, Steve; Wuttke, Stefan; Reinsch, Helge; Bein, Thomas; Stock, Norbert

    2016-06-01

    Two porphyrin-based metal-organic frameworks (MOFs) containing gallium or indium, [Ga2(OH)2(H2TCPP)]·3DMF·3H2O (Ga-PMOF) and [In2(OH)2(H2TCPP)]·3DMF·4H2O (In-PMOF) (H6TCPP = 4-tetracarboxyphenylporphyrin), were discovered using high-throughput methods. The structure was refined by the Rietveld-method starting from the structure model of Al-PMOF, [Al2(OH)2(H2TCPP)]. The new PMOFs exhibit BET surface areas between 1150 and 1400 m(2) g(-1) and are also porous toward CO2 (Ga-PMOF, 15.2 wt %; In-PMOF, 12.9 wt %). They are thermally stable in air up to 330 °C, but show limited chemical stabilities toward acids and bases. In order to achieve size control, different synthesis routes were investigated, i.e., batch synthesis at different temperatures (yield: In-PMOF-bs-th 96%, Ga-PMOF-bs-th 87%), ultrasound-assisted synthesis (yield: In-PMOF-bs-us 85%), and continuous-flow synthesis (yield: Ga-PMOF-cf 71%). By using these different methods we could control the nucleation rate and the crystal size. The crystal sizes were found to vary about 60 to 160 nm and 70 to 130 nm for Ga- and In-PMOF, respectively, which was proven by dynamic light scattering (DLS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) measurements. PMID:27203724

  4. Bio-inspired MOF-based Catalysts for Lignin Valorization.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Stavila, Vitalie; Ramakrishnan, Parthasarathi; Davis, Ryan Wesley

    2014-09-01

    Lignin is a potentially plentiful source of renewable organics, with ~50Mtons/yr produced by the pulp/paper industry and 200-300 Mtons/yr projected production by a US biofuels industry. This industry must process approximately 1 billion tons of biomass to meet the US Renewable Fuel goals. However, there are currently no efficient processes for converting lignin to value-added chemicals and drop-in fuels. Lignin is therefore an opportunity for production of valuable renewable chemicals, but presents staggering technical and economic challenges due to the quantities of material involved and the strong chemical bonds comprising this polymer. Aggressive chemistries and high temperatures are required to degrade lignin without catalysts. Moreover, chemical non-uniformity among lignins leads to complex product mixtures that tend to repolymerize. Conventional petrochemical approaches (pyrolysis, catalytic cracking, gasification) are energy intensive (400-800 degC), require complicated separations, and remove valuable chemical functionality. Low-temperature (25-200 degC) alternatives are clearly desirable, but enzymes are thermally fragile and incompatible with liquid organic compounds, making them impractical for large-scale biorefining. Alternatively, homogeneous catalysts, such as recently developed vanadium complexes, must be separated from product mixtures, while many heterogenous catalysts involve costly noble metals. The objective of this project is to demonstrate proof of concept that an entirely new class of biomimetic, efficient, and industrially robust synthetic catalysts based on nanoporous Metal- Organic Frameworks (MOFs) can be developed. Although catalytic MOFs are known, catalysis of bond cleavage reactions needed for lignin degradation is completely unexplored. Thus, fundamental research is required that industry and most sponsoring agencies are currently unwilling to undertake. We introduce MOFs infiltrated with titanium and nickel species as catalysts for

  5. Observation of single-file diffusion in a MOF.

    Science.gov (United States)

    Jobic, H

    2016-06-29

    The translational and rotational dynamics of neopentane adsorbed in the one-dimensional channels of MIL-47(V) has been studied by quasi-elastic neutron scattering. The rotational motion of neopentane is well-described by the rotational diffusion model, with a correlation time of 41 ps at 300 K. The translational motion of the molecule has been fitted by several models: isotropic diffusion, normal 1D and single-file diffusion. It is found that the observed line shapes can only be reproduced by the single-file diffusion model. The single-file mobility factor, F, is (8 ± 1) × 10(-14) m(2) s(-1/2) at 300 K. This is the first observation of this unusual diffusion behaviour in a MOF. PMID:26932296

  6. Porous Hydrogels

    Czech Academy of Sciences Publication Activity Database

    Přádný, Martin; Michálek, Jiří; Širc, Jakub

    New York: Nova Science Publishers, 2009 - (Acosta, J.; Camacho, A.), s. 57-74 ISBN 978-1-60741-401-8 R&D Projects: GA AV ČR 1QS400500558; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z40500505 Keywords : hydrogels * porous * tissue engineering Subject RIV: CD - Macromolecular Chemistry

  7. Molecular Simulation Studies of Flue Gas Purification by Bio-MOF

    OpenAIRE

    Zhi Li; Gangqiang Xu; Bei Liu; Xin Lv; Guangjin Chen; Changyu Sun; Peng Xiao; Yifei Sun

    2015-01-01

    As a new branch of MOFs which are composed of biocompatible metal ions and organic ligands, bio-metal-organic frameworks (bio-MOFs) have attracted much attention recently. Bio-MOFs feature multiple Lewis basic sites which have strong interaction with CO2 molecules, thus they have great potential in the separation and purification of gas mixtures containing CO2. In this work, molecular simulation studies were carried out to investigate the adsorption and diffusion behaviors of CO2/N2 gas mixtu...

  8. Porous coordination polymers as novel sorption materials for heat transformation processes.

    Science.gov (United States)

    Janiak, Christoph; Henninger, Stefan K

    2013-01-01

    Porous coordination polymers (PCPs)/metal-organic frameworks (MOFs) are inorganic-organic hybrid materials with a permanent three-dimensional porous metal-ligand network. PCPs or MOFs are inorganic-organic analogs of zeolites in terms of porosity and reversible guest exchange properties. Microporous water-stable PCPs with high water uptake capacity are gaining attention for low temperature heat transformation applications in thermally driven adsorption chillers (TDCs) or adsorption heat pumps (AHPs). TDCs or AHPs are an alternative to traditional air conditioners or heat pumps operating on electricity or fossil fuels. By using solar or waste heat as the operating energy TDCs or AHPs can significantly help to minimize primary energy consumption and greenhouse gas emissions generated by industrial or domestic heating and cooling processes. TDCs and AHPs are based on the evaporation and consecutive adsorption of coolant liquids, preferably water, under specific conditions. The process is driven and controlled by the microporosity and hydrophilicity of the employed sorption material. Here we summarize the current investigations, developments and possibilities of PCPs/MOFs for use in low-temperature heat transformation applications as alternative materials for the traditional inorganic porous substances like silica gel, aluminophosphates or zeolites. PMID:23945102

  9. Synthesis and CO{sub 2} adsorption study of modified MOF-5 with multi-wall carbon nanotubes and expandable graphite

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Sami, E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com; Bustam, M. A., E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com; Shariff, A. M., E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com; Elkhalifah, Ali E. I., E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com; Murshid, G., E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com; Riaz, Nadia, E-mail: samichemist1@gmail.com, E-mail: azmibustam@petronas.com.my, E-mail: azmish@petronas.com.my, E-mail: lkhlfh@gmail.com, E-mail: hmurshid@gmail.com, E-mail: nadiariazz@gmail.com [Research Center for Carbon Dioxide Capture, Dept. of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Sri Iskandar, Tronoh 31750 Perak (Malaysia)

    2014-10-24

    MOF-5 was synthesized by solvothermal method and its reactivation under anhydrous conditions. This research is conducted to investigate the effect of MOF-5 and MOF-5 modified with multi-wall carbon nanotubes (MWCNTs) and expandable graphite (EG) on the performance of CO{sub 2} adsorption. The synthesized MOFs were characterized using Field emission scanning electron microscopy (FESEM) for surface morphology, Thermogravimetric analysis (TGA) for thermal stability, X-ray diffraction (XRD) for crystals plane, Brunauer-Emmet-Teller (BET) for surface area and CO{sub 2} adsorption. The result had showed that the modified MOF-5 enhanced the CO{sub 2} adsorption compared to the pure MOF-5. The increment in the CO{sub 2} uptake capacities of MOF materials was attributed to the decrease in the pore size and enhancement of micropore volume of MOF-5 by multi-walled carbon nanotube and EG incorporation. The BET surface area of the synthesized MOF-5@MWCNTs is more than MOF-5. The CO{sub 2} sorption capacities of MOF-5 and MOF-5@MWCNTs were observed to increase from 0.00008 to 0.00048 mol g-1 at 298 K and 1 bar. The modified MOF-5@MWCNTs resulted in the highest CO{sub 2} adsorption followed by the modified MOF-5@ EG and lastly, MOF-5.

  10. Polarized three-photon-pumped laser in a single MOF microcrystal

    Science.gov (United States)

    He, Huajun; Ma, En; Cui, Yuanjing; Yu, Jiancan; Yang, Yu; Song, Tao; Wu, Chuan-De; Chen, Xueyuan; Chen, Banglin; Qian, Guodong

    2016-01-01

    Higher order multiphoton-pumped polarized lasers have fundamental technological importance. Although they can be used to in vivo imaging, their application has yet to be realized. Here we show the first polarized three-photon-pumped (3PP) microcavity laser in a single host–guest composite metal–organic framework (MOF) crystal, via a controllable in situ self-assembly strategy. The highly oriented assembly of dye molecules within the MOF provides an opportunity to achieve 3PP lasing with a low lasing threshold and a very high-quality factor on excitation. Furthermore, the 3PP lasing generated from composite MOF is perfectly polarized. These findings may eventually open up a new route to the exploitation of multiphoton-pumped solid-state laser in single MOF microcrystal (or nanocrystal) for future optoelectronic and biomedical applications. PMID:26983592

  11. Amino Functionalized SiO2 nanoparticles for seeding MOF-5

    International Nuclear Information System (INIS)

    Here we present a new type of approach for the mass production of metallorganic frameworks (MOFs). In particular, a heterogeneous process for MOF-5 growth involving amino functionalized silica nanoparticles is presented. The proposed sol-gel approach provides a promising route toward the large-scale production of colloidal MOFs by leveraging the enormous surface areas offered by nano-sized seeds used as nucleating agents. The synthesis of the ceramic seeds (SiO2 NPs) is performed at room temperature and considerable volumes of MOF crystals can be produced in 1/10 of the time required for the conventional solvothermal method. The growth of the crystals has been observed with optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and the crystal quality has been verified using X-ray powder diffraction.

  12. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    Science.gov (United States)

    Hupp, Joseph T.; Mulfort, Karen L.; Snurr, Randall Q.; Bae, Youn-Sang

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  13. Electron diffraction study of the structure of MoF5 molecule

    International Nuclear Information System (INIS)

    In the framework of a simultaneous X-ray diffraction and mass spectrometric experiments, vapours over molybdenum pentafluoride are studied at 551±10 k; Conditions are selected under which the vapour contains the only molecular form MoF5. It is found that the C2V symmetry model is best suited to the experimental data. The basic molecular parameters of MoF5 are as follows: r(Mo-F2)=1.732 (5) A, r(Mo-F2)=1.858 (8) A; r(Mo-F4)=1.845 (8) A; (F2-Mo-F3) angle=164.8 (0.4)0; (F4-Mo-F5) angle=120.6 (1.0)0. 15 refs., 3 figs., 4 tabs

  14. Polarized three-photon-pumped laser in a single MOF microcrystal

    Science.gov (United States)

    He, Huajun; Ma, En; Cui, Yuanjing; Yu, Jiancan; Yang, Yu; Song, Tao; Wu, Chuan-De; Chen, Xueyuan; Chen, Banglin; Qian, Guodong

    2016-03-01

    Higher order multiphoton-pumped polarized lasers have fundamental technological importance. Although they can be used to in vivo imaging, their application has yet to be realized. Here we show the first polarized three-photon-pumped (3PP) microcavity laser in a single host-guest composite metal-organic framework (MOF) crystal, via a controllable in situ self-assembly strategy. The highly oriented assembly of dye molecules within the MOF provides an opportunity to achieve 3PP lasing with a low lasing threshold and a very high-quality factor on excitation. Furthermore, the 3PP lasing generated from composite MOF is perfectly polarized. These findings may eventually open up a new route to the exploitation of multiphoton-pumped solid-state laser in single MOF microcrystal (or nanocrystal) for future optoelectronic and biomedical applications.

  15. Solvothermal synthesis of Fe-MOF-74 and its catalytic properties in phenol hydroxylation.

    Science.gov (United States)

    Bhattacharjee, Samiran; Choi, Jung-Sik; Yang, Seung-Tae; Choi, Sang Beom; Kim, Jaheon; Ahn, Wha-Seung

    2010-01-01

    A Fe-containing metal-organic framework, Fe-MOF-74, was solvothermally synthesized using FeCl2.4H2O and 2,5-di-hydroxy-1,4-benzenedicarboxylic acid. Characterization was conducted by XRD, BET surface area measurement, FT-IR spectroscopy, TGA, and elemental analysis, which confirmed successful preparation of Fe-MOF-74 having an identical framework structure to that reported for MOF-74. Fe-MOF-74 was found to be an effective heterogeneous catalyst for the hydroxylation of phenol using H2O2 as an oxidant; 60% phenol conversion was achieved at 20 degrees C in water with 68 and 32% selectivity to catechol and hydroquinone, respectively. The effect of temperature, phenol/H2O2 mole ratio, catalyst quantity, and solvent on catalytic performance was discussed, and a reaction mechanism is proposed based upon the experimental results. PMID:20352823

  16. Unusual regenerable porous metal-organic framework based on a new triple helical molecular necklace for separating organosulfur compounds.

    Science.gov (United States)

    Li, Shun-Li; Lan, Ya-Qian; Sakurai, Hiroaki; Xu, Qiang

    2012-12-14

    Desulfurization of fuels is receiving more and more attention all over the world due to the increase of stringent environmental regulations and fuel specifications. The metal-organic framework (MOF) is a new class of crystalline materials, and high porosity, one of the most important properties of MOFs, plays a central role in the functional properties. However, the investigation of MOFs, being employed as sorbents for adsorptive desulfurization, is still scarce. In this regard, we have constructed a new 3D porous compound 1 by using rigidly designed carboxylate ligands, which, for the first time, exhibit an unusual triple molecular necklace-like helix. The N(2) sorption isotherms of 1 show that it has a large Brunauer-Emmett-Teller (BET) surface area and pore volume. With the stable pore structure and appropriate pore sizes, compound 1 has been used as a sorbent for adsorptive desulfurization. The results indicate that compound 1 shows an excellent adsorption property and, more importantly, displays excellent stability, repeatability, and regenerability. Thus, the design and synthesis of targeted MOFs with appropriate pore size and increased interactions between organosulfur compounds and ligands/metals from MOFs is crucial for adsorptive desulfurization, which might be an effective guide to find an efficient and green adsorbent for desulfurization. PMID:23168579

  17. Identifying Highly Selective MOFs for CH4/H2 Separations using Computational Tools

    OpenAIRE

    Başdoğan, Yasemin; Sezginel, Kutay Berk; Keskin Avcı, Seda

    2015-01-01

    The large number of metal organic frameworks (MOFs) represents both an opportunity and a challenge for identification of materials exhibiting promising properties in gas separations. We used molecular simulations to screen 250 different MOP structures in order to examine their adsorption-based CH4/H-2 separation performances. Adsorption selectivity, working capacity, sorbent selection parameter, and regenerability of MOFs were calculated and compared with those of traditional nanoporous mater...

  18. Porous carbons

    Indian Academy of Sciences (India)

    Satish M Manocha

    2003-02-01

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor adsorption capacities. On activation, these exhibit increased adsorption volumes of 0.5–0.8 cm3 /gm and surface areas of 700–1800 m2 /gm depending on activation conditions, whether physical or chemical. Former carbons possess mixed pore size distribution while chemically activated carbons predominantly possess micropores. Thus, these carbons can be used for adsorption of wide distributions of molecules from gas to liquid. The molecular adsorption within the pores is due to single layer or multilayer molecule deposition at the pore walls and hence results in different types of adsorption isotherm. On the other hand, activated carbon fibres with controlled microporous structure and surface area in the range of 2500 m2 /gm can be developed by controlled pyrolysis and physical activation of amorphous carbon fibres. Active carbon fibres with unmatchable pore structure and surface characteristics are present and futuristic porous materials for a number of applications from pollution control to energy storage.

  19. Finely tuning MOFs towards high performance in C2H2 storage: synthesis and properties of a new MOF-505 analogue with an inserted amide functional group.

    Science.gov (United States)

    Zhang, Mingxing; Li, Bin; Li, Yunzhi; Wang, Qian; Zhang, Wenwei; Chen, Banglin; Li, Shuhua; Pan, Yi; You, Xiaozeng; Bai, Junfeng

    2016-06-01

    Aiming to improve the acetylene (C2H2) storage capability of MOFs, we successfully designed NJU-Bai 17, a new analogue of MOF-505 with an inserted amide functional group which exhibits almost record high C2H2 uptakes of 222.4 cm(3) g(-1) at 296 K and 296 cm(3) g(-1) at 273 K under 1 bar. This result has been further supported by the determination of the heat of C2H2 adsorption and Grand Canonical Monte Carlo (GCMC) and first-principle calculations. PMID:27173153

  20. MOF Acetylates the Histone Demethylase LSD1 to Suppress Epithelial-to-Mesenchymal Transition.

    Science.gov (United States)

    Luo, Huacheng; Shenoy, Anitha K; Li, Xuehui; Jin, Yue; Jin, Lihua; Cai, Qingsong; Tang, Ming; Liu, Yang; Chen, Hao; Reisman, David; Wu, Lizi; Seto, Edward; Qiu, Yi; Dou, Yali; Casero, Robert A; Lu, Jianrong

    2016-06-21

    The histone demethylase LSD1 facilitates epithelial-to-mesenchymal transition (EMT) and tumor progression by repressing epithelial marker expression. However, little is known about how its function may be modulated. Here, we report that LSD1 is acetylated in epithelial but not mesenchymal cells. Acetylation of LSD1 reduces its association with nucleosomes, thus increasing histone H3K4 methylation at its target genes and activating transcription. The MOF acetyltransferase interacts with LSD1 and is responsible for its acetylation. MOF is preferentially expressed in epithelial cells and is downregulated by EMT-inducing signals. Expression of exogenous MOF impedes LSD1 binding to epithelial gene promoters and histone demethylation, thereby suppressing EMT and tumor invasion. Conversely, MOF depletion enhances EMT and tumor metastasis. In human cancer, high MOF expression correlates with epithelial markers and a favorable prognosis. These findings provide insight into the regulation of LSD1 and EMT and identify MOF as a critical suppressor of EMT and tumor progression. PMID:27292636

  1. MOF Acetylates the Histone Demethylase LSD1 to Suppress Epithelial-to-Mesenchymal Transition

    Directory of Open Access Journals (Sweden)

    Huacheng Luo

    2016-06-01

    Full Text Available The histone demethylase LSD1 facilitates epithelial-to-mesenchymal transition (EMT and tumor progression by repressing epithelial marker expression. However, little is known about how its function may be modulated. Here, we report that LSD1 is acetylated in epithelial but not mesenchymal cells. Acetylation of LSD1 reduces its association with nucleosomes, thus increasing histone H3K4 methylation at its target genes and activating transcription. The MOF acetyltransferase interacts with LSD1 and is responsible for its acetylation. MOF is preferentially expressed in epithelial cells and is downregulated by EMT-inducing signals. Expression of exogenous MOF impedes LSD1 binding to epithelial gene promoters and histone demethylation, thereby suppressing EMT and tumor invasion. Conversely, MOF depletion enhances EMT and tumor metastasis. In human cancer, high MOF expression correlates with epithelial markers and a favorable prognosis. These findings provide insight into the regulation of LSD1 and EMT and identify MOF as a critical suppressor of EMT and tumor progression.

  2. Electronic and optical excitations in building blocks of the metal organic framework MOF-5

    Science.gov (United States)

    Shi, Bin; Hung, Linda; Yildirim, Taner; Ogut, Serdar

    Metal organic frameworks (MOFs) are a relatively new class of materials which are made of metal-oxide clusters linked by organic bridging ligands. In recent years, MOFs have received considerable attention due to their widely tunable structural, chemical and physical properties. We investigate one of the well characterized MOFs, MOF-5, whose framework consists of tetrahedral [Zn40]6+ units linked by rigid arylcarboxylate ligands. We use many-body perturbation (GW +BSE) and time-dependent DFT methods in real space to examine the electronic and optical excitations in the building blocks of MOF-5, such as Zn4O(COOH)6, basic zinc acetate [Zn4O(CH3COO)6], and tetranuclear zinc benzoate [Zn4O(C6H5COO)6]. The calculated spectra are compared with available experimental measurements and existing calculations to shed light on the controversy regarding the nature (metal-ligand versus ligand-ligand) of low-energy electronic and optical excitations in MOF-5. Supported by DOE Grant No. DE-SC0001853.

  3. Silver nanoparticles embedded over porous metal organic frameworks for carbon dioxide fixation via carboxylation of terminal alkynes at ambient pressure.

    Science.gov (United States)

    Molla, Rostam Ali; Ghosh, Kajari; Banerjee, Biplab; Iqubal, Md Asif; Kundu, Sudipta K; Islam, Sk Manirul; Bhaumik, Asim

    2016-09-01

    Ag nanoparticles (NPs) has been supported over a porous Co(II)-salicylate metal-organic framework to yield a new nanocatalyst AgNPs/Co-MOF and it has been thoroughly characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray spectrometry (EDX), high-resolution transmission electron microscopy (HR-TEM), UV-vis diffuse reflection spectroscopy (DRS) and N2 adsorption/desorption analysis. The AgNPs/Co-MOF material showed high catalytic activity in the carboxylation of terminal alkynes via CO2 fixation reaction to yield alkynyl carboxylic acids under very mild conditions. Due to the presence of highly reactive AgNPs bound at the porous MOF framework the reaction proceeded smoothly at 1atm CO2 pressure. Moreover, the catalyst is very convenient to handle and it can be reused for several reaction cycles without appreciable loss of catalytic activity in this CO2 fixation reaction, which suggested a promising future of AgNPs/Co-MOF nanocatalyst. PMID:27309859

  4. Design and construction of porous metal–organic frameworks based on flexible BPH pillars

    International Nuclear Information System (INIS)

    Three metal–organic frameworks (MOFs), [Co2(BPDC)2(4-BPH)·3DMF]n (1), [Cd2(BPDC)2(4-BPH)2·2DMF]n (2) and [Ni2(BDC)2(3-BPH)2 (H2O)·4DMF]n (3) (H2BPDC=biphenyl-4,4′-dicarboxylic acid, H2BDC=terephthalic acid, BPH=bis(pyridinylethylidene)hydrazine and DMF=N,N′-dimethylformamide), have been solvothermally synthesized based on the insertion of heterogeneous BPH pillars. Framework 1 has “single-pillared” MOF-5-like motif with inner cage diameters of up to 18.6 Å. Framework 2 has “double pillared” MOF-5-like motif with cage diameters of 19.2 Å while 3 has “double pillared” 8-connected framework with channel diameters of 11.0 Å. Powder X-ray diffraction (PXRD) shows that 3 is a dynamic porous framework. - Graphical abstract: By insertion of flexible BPH pillars based on “pillaring” strategy, three metal–organic frameworks are obtained showing that the porous frameworks can be constructed in a much greater variety. Highlights: ► Frameworks 1 and 2 have MOF-5 like motif. ► The cube-like cages in 1 and 2 are quite large, comparable to the IRMOF-10. ► Framework 1 is “single-pillared” mode while 2 is “double-pillared” mode. ► PXRD and gas adsorption analysis show that 3 is a dynamic porous framework.

  5. Hydrogen-Bonded Organic Frameworks (HOFs): A New Class of Porous Crystalline Proton-Conducting Materials.

    Science.gov (United States)

    Karmakar, Avishek; Illathvalappil, Rajith; Anothumakkool, Bihag; Sen, Arunabha; Samanta, Partha; Desai, Aamod V; Kurungot, Sreekumar; Ghosh, Sujit K

    2016-08-26

    Two porous hydrogen-bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra-high proton conduction values (σ) 0.75× 10(-2)  S cm(-1) and 1.8×10(-2)  S cm(-1) under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic-based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials. PMID:27464784

  6. Aerogels of 1D Coordination Polymers: From a Non-Porous Metal-Organic Crystal Structure to a Highly Porous Material

    Directory of Open Access Journals (Sweden)

    Adrián Angulo-Ibáñez

    2016-01-01

    Full Text Available The processing of an originally non-porous 1D coordination polymer as monolithic gel, xerogel and aerogel is reported as an alternative method to obtain novel metal-organic porous materials, conceptually different to conventional crystalline porous coordination polymer (PCPs or metal-organic frameworks (MOFs. Although the work herein reported is focused upon a particular kind of coordination polymer ([M(μ-ox(4-apy2]n, M: Co(II, Ni(II, the results are of interest in the field of porous materials and of MOFs, as the employed synthetic approach implies that any coordination polymer could be processable as a mesoporous material. The polymerization conditions were fixed to obtain stiff gels at the synthesis stage. Gels were dried at ambient pressure and at supercritical conditions to render well shaped monolithic xerogels and aerogels, respectively. The monolithic shape of the synthesis product is another remarkable result, as it does not require a post-processing or the use of additives or binders. The aerogels of the 1D coordination polymers are featured by exhibiting high pore volumes and diameters ranging in the mesoporous/macroporous regions which endow to these materials the ability to deal with large-sized molecules. The aerogel monoliths present markedly low densities (0.082–0.311 g·cm−3, an aspect of interest for applications that persecute light materials.

  7. Microwave-assisted modulated synthesis of zirconium-based metal-organic framework (Zr-MOF) for hydrogen storage applications

    International Nuclear Information System (INIS)

    Zirconium-based metal-organic framework (Zr-MOF) was synthesized using a microwave-assisted modulated method in a short reaction time of 5 min. The Zr-MOF material was highly crystalline with well-defined octahedral shaped crystals, and it exhibited comparable hydrogen storage capacity to Zr-MOF of similar specific surface area synthesized using conventional methods with much longer synthesis time. (orig.)

  8. Robustness and Thermophysical Properties of MOF-5: A Prototypical Hydrogen Storage Material

    Science.gov (United States)

    Ming, Yang

    Metal-organic frameworks (MOFs) are an emerging class of microporous, crystalline materials with potential applications in the capture, storage, and separation of gasses. Of the many known MOFs, the compound known as MOF-5 has attracted considerable attention due to its ability to store gaseous fuels at low pressure with high densities. However, low thermal conductivity and limited robustness upon exposure to water and other reactive species are two challenges which limit the application of MOF-5; similar issues plague several other MOFs. The focus of this dissertation is to understand and overcome these shortcomings through detailed experimental and computational characterization of the prototype compound, MOF-5. The insight provided by this study regarding the properties of MOFs will aid in the transition of these materials from lab bench to applications. Improvements to the thermal conductivity of MOF-5 are demonstrated using densified pellets consisting of a physical mixture of MOF-5 and expanded natural graphite (ENG). The high-aspect ratio of ENG particles, combined with uni-axial compression, results in anisotropic microstructural and thermal transport properties in the pellets. Perpendicular to the pressing direction the thermal conductivity was observed to be two to four times higher than in the orthogonal direction. We further demonstrate that this anisotropy can be exploited to enhance conductivity along a preferred direction in the pellets by altering the pellet processing conditions. We conclude that the low thermal conductivity typical of MOFs can be improved using a judicious combination of second phase additions and processing techniques. Regarding robustness, we first quantify experimentally the impact of humid air exposure on the properties of MOF-5 as a function of exposure time, humidity level, and morphology (i.e., powders vs. pellets). For humidity levels below 50% only minor degradation is observed for exposure times up to several hours. In

  9. Thermodynamics of solvent interaction with the metal-organic framework MOF-5.

    Science.gov (United States)

    Akimbekov, Zamirbek; Wu, Di; Brozek, Carl K; Dincă, Mircea; Navrotsky, Alexandra

    2016-01-14

    The inclusion of solvent in metal-organic framework (MOF) materials is a highly specific form of guest-host interaction. In this work, the energetics of solvent MOF-5 interactions has been investigated by solution calorimetry in 5 M sodium hydroxide (NaOH) at room temperature. Solution calorimetric measurement of enthalpy of formation (ΔH(f)) of Zn4O(C8H4O4)3·C3H7NO (MOF-5·DMF) and Zn4O(C8H4O4)3·0.60C5H11NO (MOF-5·0.60DEF) from the dense components zinc oxide (ZnO), 1,4-benzenedicarboxylic acid (H2BDC), N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF) gives values of 16.69 ± 1.21 and 45.90 ± 1.46 kJ (mol Zn4O)(-1), respectively. The enthalpies of interaction (ΔH(int)) for DMF and DEF with MOF-5 are -82.78 ± 4.84 kJ (mol DMF)(-1) and -89.28 ± 3.05 kJ (mol DEF)(-1), respectively. These exothermic interaction energies suggest that, at low guest loading, Lewis base solvents interact more strongly with electron accepting Zn4O clusters in the MOF than at high solvent loading. These data provide a quantitative thermodynamic basis to investigate transmetallation and solvent assisted linker exchange (SALE) methods and to synthesize new MOFs. PMID:26658672

  10. Development and Test Evaluations for Ni-DOBDC Metal Organic Framework (MOF) Engineered Forms

    Energy Technology Data Exchange (ETDEWEB)

    Troy G. Garn; Mitchell Greenhalgh

    2013-07-01

    A joint effort to prepare engineered forms of a Ni-DOBDC metal organic framework (MOF) was completed with contributions from PNNL, SNL and the INL. Two independent methods were used at INL and SNL to prepare engineered form (EF) sorbents from Ni-DOBDC MOF powder developed and prepared at PNNL. Xe and Kr capacity test evaluations were performed at ambient temperature with the cryostat experimental setup at INL. The initial INL EF MOF test results indicated a Xe capacity of 1.6 mmol/kg sorbent and no Kr capacity. A large loss of surface area also occurred during minimal testing rendering the INL EF MOF unusable. Four capacity tests were completed using the SNL EF MOF at ambient temperature and resulted in Xe capacities of 1.4, 4.2, 5.0 and 3.8 mmol/kg sorbent with no Kr capacity observed in any ambient temperature tests. Two additional capacity tests were performed at 240 K to further evaluate SNL EF MOF performance. Xe capacities of 50.7 and 49.3 mmol/kg of sorbent and Kr capacities of 0.77 and 0.69 mmol/kg of sorbent were obtained, respectively. Following the adsorption evaluations, the SNL EF MOF material had lost about 40 % of the initial mass and 40 % of the initial surface area. In general, the Xe capacity results at ambient temperature for the INL and SNL EF Ni-DOBDC MOF’s were lower than 9.8 mmol Xe/kg sorbent test results reported by INL in FY-12 using PNNL’s inital EF supplied material.

  11. ZIF-Derived Nitrogen-Doped Porous Carbons for Xe Adsorption and Separation

    Science.gov (United States)

    Zhong, Shan; Wang, Qian; Cao, Dapeng

    2016-01-01

    Currently, finding high capacity adsorbents with large selectivity to capture Xe is still a great challenge. In this work, nitrogen-doped porous carbons were prepared by programmable temperature carbonization of zeolitic imidazolate framework-8 (ZIF-8) and ZIF-8/xylitol composite precursors and the resultant samples are marked as Carbon-Z and Carbon-ZX, respectively. Further adsorption measurements indicate that ZIF-derived nitrogen-doped Carbon-ZX exhibits extremely high Xe capacity of 4.42 mmol g−1 at 298 K and 1 bar, which is higher than almost all other pristine MOFs such as CuBTC, Ni/DOBDC, MOF-5 and Al-MIL-53, and even more than three times of the matrix ZIF-8 at similar conditions. Moreover, Carbon-ZX also shows the highest Xe/N2 selectivity about ~120, which is much larger than all other reported MOFs. These remarkable features illustrate that ZIF-derived nitrogen-doped porous carbon is an excellent adsorbent for Xe adsorption and separation at room temperature. PMID:26883471

  12. ZIF-Derived Nitrogen-Doped Porous Carbons for Xe Adsorption and Separation.

    Science.gov (United States)

    Zhong, Shan; Wang, Qian; Cao, Dapeng

    2016-01-01

    Currently, finding high capacity adsorbents with large selectivity to capture Xe is still a great challenge. In this work, nitrogen-doped porous carbons were prepared by programmable temperature carbonization of zeolitic imidazolate framework-8 (ZIF-8) and ZIF-8/xylitol composite precursors and the resultant samples are marked as Carbon-Z and Carbon-ZX, respectively. Further adsorption measurements indicate that ZIF-derived nitrogen-doped Carbon-ZX exhibits extremely high Xe capacity of 4.42 mmol g(-1) at 298 K and 1 bar, which is higher than almost all other pristine MOFs such as CuBTC, Ni/DOBDC, MOF-5 and Al-MIL-53, and even more than three times of the matrix ZIF-8 at similar conditions. Moreover, Carbon-ZX also shows the highest Xe/N2 selectivity about ~120, which is much larger than all other reported MOFs. These remarkable features illustrate that ZIF-derived nitrogen-doped porous carbon is an excellent adsorbent for Xe adsorption and separation at room temperature. PMID:26883471

  13. ZIF-Derived Nitrogen-Doped Porous Carbons for Xe Adsorption and Separation

    Science.gov (United States)

    Zhong, Shan; Wang, Qian; Cao, Dapeng

    2016-02-01

    Currently, finding high capacity adsorbents with large selectivity to capture Xe is still a great challenge. In this work, nitrogen-doped porous carbons were prepared by programmable temperature carbonization of zeolitic imidazolate framework-8 (ZIF-8) and ZIF-8/xylitol composite precursors and the resultant samples are marked as Carbon-Z and Carbon-ZX, respectively. Further adsorption measurements indicate that ZIF-derived nitrogen-doped Carbon-ZX exhibits extremely high Xe capacity of 4.42 mmol g-1 at 298 K and 1 bar, which is higher than almost all other pristine MOFs such as CuBTC, Ni/DOBDC, MOF-5 and Al-MIL-53, and even more than three times of the matrix ZIF-8 at similar conditions. Moreover, Carbon-ZX also shows the highest Xe/N2 selectivity about ~120, which is much larger than all other reported MOFs. These remarkable features illustrate that ZIF-derived nitrogen-doped porous carbon is an excellent adsorbent for Xe adsorption and separation at room temperature.

  14. Study on preparation and characterization of MOF based lanthanide doped luminescent coordination polymers

    International Nuclear Information System (INIS)

    Coordination polymers (metal–organic frameworks or MOFs) offer the opportunity for fine-tuning the luminescence behavior because of the possibility to entrap in the network pores molecules that can influence the lanthanide (Ln) emission. In this study, Zn (II) and polycarboxylate based MOFs were first pre-formed by solvothermal method, then considered as host-matrix for in situ doping of low-input concentration of Eu3+ and Tb3+ (two most commonly used lanthanides in life science assays), and afterwards lanthanide doped luminescent materials were synthesized. Different characterizations (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS)) were carried out to confirm accordingly MOF's crystallinity, the structure and chemical composition. The study on luminescent properties of the material has revealed an efficient energy transfer from the ligand excited states to the Eu3+ and Tb3+ f-excited states. With quite low input concentrations (8–15%) of doped rare earth ions, these complexes displayed intense emissions at room temperature and proved to be good candidates for red and green emitter luminescent materials. Generally, this design concept can be extended for the preparation of other rare earth coordination polymers. - Highlights: • Synthesis of luminescent materials MOF-5/RE (RE = Eu, Tb) by solvothermal method with in situ doping of Eu3+ and Tb3+. • MOF-5/RE with ordered structure gives strong luminescence spectra. • The design concept can be extended for the preparation of other rare earth coordination polymers

  15. Hydrogen adsorption on metal-organic frameworks (MOFs) and single-walled carbon nanotubes (SWNTs)

    International Nuclear Information System (INIS)

    'Full text:' In recent years, several novel carbon-based microporous materials such as single-walled carbon nanotubes (SWNTs) and metal-organic frameworks (MOFs) have been proposed as promising adsorbents for hydrogen. Hydrogen adsorption measurements on Al-, Cr- and Zn-based metal-organic frameworks (MOFs) and single-walled carbon nanotubes (SWNTs) are presented. The measurements were performed at temperatures ranging from 77 to 300K and pressures up to 50 atm using a volumetric approach. The maximum excess adsorption at 77K ranges from 2,8 to 3,9 wt % for the MOFs and from 1,5 to 2,5 wt % for the SWNTs. These values are reached at pressures below 40 atm. At room temperature and 40 atm, modest amounts of hydrogen are adsorbed (< 0,4 wt %). A Dubinin-Astakhov (DA) approach is used to investigate the measured adsorption isotherms and retrieve energetic and structural parameters. The adsorption enthalpy averaged over filling is found to be about 2,9 kJ/mol for the MOF-5 and about 3,6 - 4,2 kJ/mol for SWNTs. The uptake of hydrogen on SWNTs and MOF-5 appears to be due to physisorption and can be described, through the DA-model, by a traditional theory of micropore filling. (author)

  16. Synthesis of Zn-MOF incorporating titanium-hydrides as active sites binding H2 molecules

    International Nuclear Information System (INIS)

    This paper describes the synthetic effort for a Zn-MOF imparting Ti-H as a preferential binding site potentially capturing H2 molecules via Kubas-type interaction. The formation mechanism of Ti-H innate to the final material was potentially demonstrated to follow a radical dissociation rather than a β-hydrogen elimination and a C-H reductive elimination. - Graphical abstract: This study details the synthesis and the formation mechanism of Zn-MOF adsorbent site-isolating TiH3 that can potentially capture H2 molecules via Kubas-binding mechanism. - Highlights: • OH-functionalized Zn-MOF was employed as a reactive template to site-isolate TiH3. • This MOF was post-synthetically modified using a tetracyclohexyl titanium (IV). • This intermediate was hydrogenolyzed to change ligand from cyclohexyl to hydride. • Formation mechanism of TiH3 was investigated via two control GC–MS experiments. • Final Zn-MOF potentially site-isolating TiH3 species was used as a H2 adsorbent

  17. Capturing the H 2 –Metal Interaction in Mg-MOF-74 Using Classical Polarization

    KAUST Repository

    Pham, Tony

    2014-10-02

    © 2014 American Chemical Society. Grand canonical Monte Carlo (GCMC) simulations of H2 sorption were performed in Mg-MOF-74, a metal-organic framework (MOF) that displays very high H2 sorption affinity. Experimental H2 sorption isotherms and isosteric heats of adsorption (Qst) values were reproduced using a general purpose materials sorption potential that includes many-body polarization interactions. In contrast, using two models that include only charge-quadrupole interactions failed to reproduce such experimental measurements even though they are the type normally employed in such classical force field calculations. Utilizing the present explicit polarizable model in GCMC simulation resulted in a Mg2+-H2 distance of 2.60 Å, which is close to a previously reported value that was obtained using electronic structure methods and comparable to similar experimental measurements. The induced dipole distribution obtained from simulation assisted in the characterization of two previously identified sorption sites in the MOF: the Mg2+ ions and the oxido group of the linkers. The calculated two-dimensional quantum rotational levels for a H2 molecule sorbed onto the Mg2+ ion were in good agreement with experimental inelastic neutron scattering (INS) data. Although the H2-metal interaction in MOFs may be thought of as a quantum mechanical effect, this study demonstrates how the interaction between the sorbate molecules and the open-metal sites in a particular highly sorbing MOF can be captured using classical simulation techniques that involve a polarizable potential.

  18. Porous Ascend

    DEFF Research Database (Denmark)

    Riiber, Jacob; Tamke, Martin; Ramsgaard Thomsen, Mette

    2012-01-01

    towards a novel approach to working with, and reproducing, complexity within collections of architectural components. With no predefined coordinization mapping the ever changing fractal pattern, building proceeds by a locally defined identification and pairing of elements. In this way the project......The Porous Ascend project investigates how algorithmic and generative approaches allows for the utilization of complex, and by other means inaccessible, ways of devising the schema by which we arrange the parts of an architectural object. It does so by pursuing to physically realize a structure of...... folded elements, based on the concept of applying recursion to the geometry of the non-periodic Penrose tiling. Within this process the project explores questions regarding the making of bespoke digital design tools, digital production, material behaviour and assemblage strategies. The project points...

  19. Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

    KAUST Repository

    Babarao, Ravichandar

    2010-07-06

    The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.

  20. Demonstrate the removal efficiency and capacity of MOF materials for krypton recovery

    Energy Technology Data Exchange (ETDEWEB)

    Thallapally, Praveen K.; Liu, Jian; Strachan, Denis M.

    2013-08-23

    Metal organic framework materials (MOFs) were developed and tested in support of the U.S. Department of Energy Office of Nuclear Energy, Fuel Cycle Technology Separations and Waste Forms Campaign. Specifically, materials are being developed for the removal of xenon (Xe) and krypton (Kr) from gaseous products of nuclear fuel reprocessing unit operations. Two metal organic framework structures were investigated in greater detail to demonstrate the removal efficiency and capacity of MOF materials for krypton recovery. Our two bed breakthrough measurements on NiDOBDC and FMOFCu indicate these materials can capture and separate parts per million levels of Xe and Kr from air. The removal efficiency and adsorption capacity for Kr on these two MOFs were further increased upon removal of Xe upfront.

  1. Molecular structure of MoF5 by synchronous electron diffraction and mass-spectrometric experiment

    International Nuclear Information System (INIS)

    Electron diffraction data for MoF5 molecule are analyzed in terms of rα-structure. Three models of D3h, C4v, C2v symmetry geometric structure are studied. The conclusion that a model of C2v symmetry distorted bipyramid with Mo-F internuclear distance three different types: rα(Mo-F1eq)1.720 (5) A, rα(Mo-F2eq) 1.826 (7) A, rα(Mo-Fax) 1.852 (7) A, Corresponds to the experimental electron diffraction data. Valent angle between pseudoaxial bonds constitutes 168.10 (0.6)0, - between pseudoequatorial bonds, Mo-F2eq, 122.6 (0.8)0. 19 refs., 3 figs., 6 tabs

  2. Electrocatalytically Active MOF/Graphite Oxide Hybrid for Electrosynthesis of Dimethyl Carbonate

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: Electrochemical oxidative carbonylation of methanol with CO to dimethyl carbonate from heterogeneous electrocatalyst was studied at normal temperature and pressure. For the purpose of decrease the crystalline size and the agglomerative force of metal-organic framework (MOF), this paper first introduced graphite oxide (GO) into MOF/GO hybrid material with enhanced electrocatalytic performance and the stability of electrocatalyst for the dimethyl carbonate (DMC) synthesis. The introduction of GO is important to build the hybrid materials with synergistic properties. The composite materials and its parent materials were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and the electrochemical property of the samples was measured. The results show that the MOF/GO was active for the electrolytic reaction and could be reused at least five times. A plausible Cu(II)/Cu(I) electrocatalytic cycle mechanism was proposed

  3. Design and Synthesis of an MOF Thermometer with High Sensitivity in the Physiological Temperature Range.

    Science.gov (United States)

    Zhao, Dian; Rao, Xingtang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2015-12-01

    An important result of research on mixed-lanthanide metal-organic frameworks (M'LnMOFs) is the realization of highly sensitive ratiometric luminescent thermometers. Here, we report the design and synthesis of the new M'LnMOF Tb0.80Eu0.20BPDA with high relative sensitivity in the physiological temperature regime (298-318 K). The emission intensity and luminescence lifetime were investigated and compared to those of existing materials. It was found that the temperature-dependent luminescence properties of Tb0.80Eu0.20BPDA are strongly associated with the distribution of the energy levels of the ligand. Such a property can be useful in the design of highly sensitive M'LnMOF thermometers. PMID:26575207

  4. Separation of C2 Hydrocarbons by Porous Materials: Metal Organic Frameworks as Platform

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Debasis; Liu, Jun; Thallapally, Praveen K.

    2014-12-22

    The effective separation of small hydrocarbon molecules (C1 – C4) is an important process for petroleum industry, determining the end price of many essential commodities in our daily lives. Current technologies for separation of these molecules rely on energy intensive fractional distillation processes at cryogenic temperature, which is particularly difficult because of their similar volatility. In retrospect, adsorptive separation using solid state adsorbents might be a cost effective alternative. Several types of solid state adsorbents (e.g. zeolite molecular sieves) were tested for separation of small hydrocarbon molecules as a function of pressure, temperature or vacuum. Among different types of plausible adsorbents, metal organic frameworks (MOFs), a class of porous, crystalline, inorganic-organic hybrid materials, is particularly promising. In this brief comment article, we discuss the separation properties of different types of solid state adsorbents, with a particular emphasis on MOF based adsorbents for separation of C2 hydrocarbon molecules.

  5. Uranium purification process in the 'FLUOREX' system. Adsorption mechanism of MoF6 on MgF2

    International Nuclear Information System (INIS)

    The nuclear fuel reprocessing technology FLUOREX is a hybrid system based on a fluoride volatility and a solvent extraction technique. Most of the uranium in the spent nuclear fuel is fluorinated, and recovered as UF6 gas. Because UF6 contains some volatile fluorides of fission products (FPs), we proposed to eliminate the FPs from UF6 by adsorbing them on fluoride adsorbents. We experimentally examined the adsorption amount of MoF6, one of the volatile FPs, on MgF2 adsorbent and considered the adsorption structure by the first principle calculation code ABINIT. The saturated adsorption amount at 423 K was constant at 1.3 ± 0.4 mg/m2 with no dependence on MoF6 pressure from 10-4 to 10-1 kPa, which covered the MoF6 partial pressure range in the actual process. According to the saturated adsorption amount, we supposed that only a mono layer of MoF6 molecules was adsorbed on the MgF2 surface. The calculation results showed that MoF6 was adsorbed on MgF2 by bonding F atoms of MoF6 with Mg atoms of the MgF2 surface and that the MoF6 adsorption on MoF6 layer occurred with some difficulty; these results explained the adsorption structure suggested by the saturated adsorption amount. (author)

  6. Metal-Organic Frameworks: Building Block Design Strategies for the Synthesis of MOFs.

    KAUST Repository

    Luebke, Ryan

    2014-09-01

    A significant and ongoing challenge in materials chemistry and furthermore solid state chemistry is to design materials with the desired properties and characteristics. The field of Metal-Organic Frameworks (MOFs) offers several strategies to address this challenge and has proven fruitful at allowing some degree of control over the resultant materials synthesized. Several methodologies for synthesis of MOFs have been developed which rely on use of predetermined building blocks. The work presented herein is focused on the utilization of two of these design principles, namely the use of molecular building blocks (MBBs) and supermolecular building blocks (SBBs) to target MOF materials having desired connectivities (topologies). These design strategies also permit the introduction of specific chemical moieties, allowing for modification of the MOFs properties. This research is predominantly focused on two platforms (rht-MOFs and ftw-MOFs) which topologically speaking are edge transitive binodal nets; ftw being a (4,12)-connected net and rht being a (3,24)-connected net. These highly connected nets (at least one node having connectivity greater than eight) have been purposefully targeted to increase the predictability of structural outcome. A general trend in topology is that there is an inverse relationship between the connectivity of the node(s) and the number of topological outcomes. Therefore the key to this research (and to effective use of the SBB and MBB approaches) is identification of conditions which allow for reliable formation of the targeted MBBs and SBBs. In the case of the research presented herein: a 12-connected Group IV or Rare Earth based hexanuclear MBB and a 24-connected transition metal based SBB were successfully targeted and synthesized. These two synthetic platforms will be presented and used as examples of how these design methods have been (and can be further) utilized to modify existing materials or develop new materials for gas storage and

  7. Reticular synthesis of HKUST-like tbo MOFs with enhanced CH4 storage

    KAUST Repository

    Spanopoulos, Ioannis

    2015-12-22

    Successful implementation of reticular chemistry using a judiciously designed rigid octatopic carboxylate organic linker allowed the construction of expanded HKUST-1-like tbo-MOF series with intrinsic strong CH4 adsorption sites. The Cu-analogue displayed a concomitant enhancement of the gravimetric and volumetric surface area with the highest reported CH4 uptake among the tbo family, comparable to the best performing MOFs for CH4 storage. The corresponding gravimetric (BET) and volumetric surface area of 3971 m2 g-1 and 2363 m2 cm-3 represent an increase of respectively 115 % and 47 % in comparison to the corresponding values for the prototypical HKUST-1 (tbo-MOF-1), and 42 % and 20 % higher than tbo-MOF-2. High pressure methane adsorption isotherms revealed a high total gravimetric and volumetric CH4 uptakes, reaching 372 cm3 (STP) g-1 and 221 cm3 (STP) cm-3 respectively at 85 bar and 298 K. The corresponding working capacities between 5-80 bar were found to be 294 cm3 (STP) g-1 and 175 cm3 (STP) cm-3 and are placed among the best performing MOFs for CH4 storage particularly at relatively low temperature (e.g. 326 cm3 (STP) g-1 and 194 cm3 (STP) cm-3 at 258 K). To better understand the structure-property relationship and gain insight on the mechanism accounting for the resultant enhanced CH4 storage capacity, molecular simulation study was performed and revealed the presence of very strong CH4 adsorption sites at the vicinity of the organic linker with similar adsorption energetics as the open metal sites. The present findings supports the potential of tbo-MOFs based on the supermolecular building layer (SBL) approach as an ideal platform to further enhance the CH4 storage capacity via expansion and functionalization of the quadrangular pillars.

  8. First tetrazole-bridged d-f heterometallic MOFs with a large magnetic entropy change.

    Science.gov (United States)

    Hu, Huan-Cheng; Kang, Xiao-Min; Cao, Chun-Shuai; Cheng, Peng; Zhao, Bin

    2015-07-11

    A novel 3D tetrazole-bridged 3d-4f heterometallic MOF {(H3O)3[Gd3Mn2(Trz)4]·12H2O}n (1) with a hexanuclear [Gd6] cluster was obtained via in situ [2+3] cycloaddition reaction and structurally characterized, possessing good solvent and thermal stabilities, as well as a large magnetic entropy change -ΔS(m) = 40.3 J kg(-1) K(-1) for ΔH = 7 T at 2.0 K. To our knowledge, it is the first example of tetrazole-bridged 3d-4f heterometallic MOFs. PMID:26051815

  9. A cationic copper(I) iodide cluster MOF exhibiting unusual ligand assisted thermochromism.

    Science.gov (United States)

    Yadav, Ashok; Srivastava, Anant Kumar; Balamurugan, Ayyakkalai; Boomishankar, Ramamoorthy

    2014-06-14

    By employing a tridentate thiophosphoramide ligand, [(NHAQ)3P[double bond, length as m-dash]S] (AQ = 3-quinolinyl), a cationic MOF, {[Cu6I5(L(1))2](OH)·3DMF·2.5MeOH}n, was synthesized. Photo-physical studies on the 2D-MOF showed an unusual thermochromic behaviour emitting a blue fluorescence at 298 K due to the AQ chromophore and an orange-yellow phosphorescence at 77 K due to the [Cu6I5](+) unit. PMID:24760039

  10. The unique rht-MOF platform, ideal for pinpointing the functionalization and CO 2 adsorption relationship

    KAUST Repository

    Luebke, Ryan

    2012-01-01

    The uniqueness of the rht-MOF platform, based on the singular (3,24)-connected net, allows for the facile design and synthesis of functionalized materials for desired applications. Here we designed a nitrogen-rich trefoil hexacarboxylate (trigonal tri-isophthalate) ligand, which serves to act as the trigonal molecular building block while concurrently coding the formation of the targeted truncated cuboctahedral supermolecular building block (in situ), and enhancing the CO 2 uptake in the resultant rht-MOF. © 2012 The Royal Society of Chemistry.

  11. The effect of solution/free volume ratio on the MOF-5 characteristics

    International Nuclear Information System (INIS)

    The influence of solution/free volume ratio on the specific surface area and pore volume of MOF-5 was investigated. MOF-5 was synthesized, by solvothermal reaction, using an identical starting mixture, at different solution/free volume ratio of 0.245, 0.807 and 3.429. The specific surface area decreased from 3018 m2/g to 2680 m2/g and 1099 m2/g respectively. The nitrogen adsorption capacity decrease in the same manner from 817.35 cm3/g to 740.75 cm3/g and 294.56 cm3/g respectively.

  12. A MOF platform for incorporation of complementary organic motifs for CO2 binding.

    Science.gov (United States)

    Deria, Pravas; Li, Song; Zhang, Hongda; Snurr, Randall Q; Hupp, Joseph T; Farha, Omar K

    2015-08-11

    CO2 capture is essential for reducing the carbon footprint of coal-fired power plants. Here we show, both experimentally and computationally, a new design strategy for capturing CO2 in nanoporous adsorbents. The approach involves 'complementary organic motifs' (COMs), which have a precise alignment of charge densities that is complementary to the CO2 quadrupole. Two promising COMs were post-synthetically incorporated into a robust metal-organic framework (MOF) material using solvent-assisted ligand incorporation (SALI). We demonstrate that these COM-functionalized MOFs exhibit high capacity and selectivity for CO2 relative to other reported motifs. PMID:26145451

  13. Post-assembly transformations of porphyrin-containing metal-organic framework (MOF) films fabricated via automated layer-by-layer coordination

    KAUST Repository

    So, Monica

    2015-01-01

    Herein, we demonstrate the robustness of layer-by-layer (LbL)-assembled, pillared-paddlewheel-type MOF films toward conversion to new or modified MOFs via solvent-assisted linker exchange (SALE) and post-assembly linker metalation. Further, we show that LbL synthesis can afford MOFs that have proven inaccessible through other de novo strategies.

  14. 金属骨架有机多孔碳的制备及其在锂空气电池中的应用∗%Preparation of Porous Carbon Based on Metal Organic Framework and Its Application for Lithium-Air Battery

    Institute of Scientific and Technical Information of China (English)

    王先友; 宋云峰; 白艳松; 江兰兰; 舒洪波; 杨秀康; 王灏; 赵青蓝; 易兰花

    2014-01-01

    A metal organic framework porous carbon (MOF-PC)has been prepared by terephthalic acid-zinc complex (MOF-5)and employed in lithium oxygen batteries for the first time.The physical and elec-trochemical properties of the as-prepared carbon sample are investigated by powder X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),N2 adsorption-desorption isotherm and galvanostatic charge/discharge.The results show that the as-prepared MOF-PC is amorphous structure with a specific surface area of 654 m2 ·g-1 .The lithium oxygen battery using the MOF-PC carbon black as air electrode shows a higher capacity of 3 183 mAh·g-1 at a current density of 0.1 mA·cm-2 ,it increased about 90% capacity compared to traditional Super P carbon black.%以苯二甲酸-锌配位化合物(MOF-5)为原料合成金属骨架有机多孔碳MOF-PC,并首次应用于锂空气电池.采用XRD、SEM、TEM、氮气脱吸附和恒流充放电测试研究了MOF-PC的物理及电化学性能.结果表明,样品MOF-PC为无定型碳,比表面积为654 m2·g-1.以MOF-PC为空气电极的锂空气电池在0.1 mA·cm-2电流密度下放电比容量高达3183 mAh·g-1,比传统碳材料(Super P)在相同电流密度下的容量高90%.

  15. Pentiptycene-Based Luminescent Cu (II) MOF Exhibiting Selective Gas Adsorption and Unprecedentedly High-Sensitivity Detection of Nitroaromatic Compounds (NACs)

    Science.gov (United States)

    Zhang, Minghui; Zhang, Liangliang; Xiao, Zhenyu; Zhang, Qinhui; Wang, Rongming; Dai, Fangna; Sun, Daofeng

    2016-02-01

    The assembly of a fluorescent pentiptycene-based ligand with copper ion resulted in the formation of a 3D porous metal-organic framework (UPC-21) based on well-known paddlewheel SBUs. UPC-21 exhibits selective adsorption of CO2 over CH4 and N2 at 273 K and 295 K, C2H2 over CH4 at 273 K. The most significant performance of UPC-21 is its highly efficient detection of NACs such as 4-NP, 1,4-DNB, NB, and 1,3-DNB with the calculated quenching constants, Ksv, being 3.097 × 106, 1.406 × 106, 4.420 × 105, and 1.498 × 105 M-1 for 4-NP, 1,4-DNB, NB, 1,3-DNB, respectively, which keeps a record on the fluorescence detection of NACs. This is the first porous Cu(II) MOF that exhibits fluorescent detection of NACs with high sensitivities.

  16. Pentiptycene-Based Luminescent Cu (II) MOF Exhibiting Selective Gas Adsorption and Unprecedentedly High-Sensitivity Detection of Nitroaromatic Compounds (NACs)

    Science.gov (United States)

    Zhang, Minghui; Zhang, Liangliang; Xiao, Zhenyu; Zhang, Qinhui; Wang, Rongming; Dai, Fangna; Sun, Daofeng

    2016-01-01

    The assembly of a fluorescent pentiptycene-based ligand with copper ion resulted in the formation of a 3D porous metal-organic framework (UPC-21) based on well-known paddlewheel SBUs. UPC-21 exhibits selective adsorption of CO2 over CH4 and N2 at 273 K and 295 K, C2H2 over CH4 at 273 K. The most significant performance of UPC-21 is its highly efficient detection of NACs such as 4-NP, 1,4-DNB, NB, and 1,3-DNB with the calculated quenching constants, Ksv, being 3.097 × 106, 1.406 × 106, 4.420 × 105, and 1.498 × 105 M−1 for 4-NP, 1,4-DNB, NB, 1,3-DNB, respectively, which keeps a record on the fluorescence detection of NACs. This is the first porous Cu(II) MOF that exhibits fluorescent detection of NACs with high sensitivities. PMID:26857592

  17. 3D hybrid-porous carbon derived from carbonization of metal organic frameworks for high performance supercapacitors

    Science.gov (United States)

    Bao, Weizhai; Mondal, Anjon Kumar; Xu, Jing; Wang, Chengyin; Su, Dawei; Wang, Guoxiu

    2016-09-01

    We report a rational design and synthesis of 3D hybrid-porous carbon with a hierarchical pore architecture for high performance supercapacitors. It contains micropores (carbonization of unique porous metal organic frameworks (MOFs). Owning to the synergistic effect of micropores and mesopores, the hybrid-porous carbon has exceptionally high ion-accessible surface area and low ion diffusion resistance, which is desired for supercapacitor applications. When applied as electrode materials in supercapacitors, 3D hybrid-porous carbon demonstrates a specific capacitance of 332 F g-1 at a constant charge/discharge current of 500 mA g-1. The supercapacitors can endure more than 10,000 cycles without degradation of capacitance.

  18. Adsorption isotherms and selectivity of CO/N2/CO2 on MOF-74(Ni)%CO/N2/CO2在MOF-74(Ni)上吸附相平衡和选择性

    Institute of Scientific and Technical Information of China (English)

    刘有毅; 黄艳; 何嘉杰; 肖静; 夏启斌; 李忠

    2015-01-01

    This work investigates the adsorption performance of adsorbent MOF-74(Ni) for CO/N2 and CO2/CO2 binary gas mixtures. Adsorbent MOF-74(Ni) with high density of coordinatively unsaturated sites was synthesized by a hydrothermal method, and characterized with N2 adsorption, P-XRD, and SEM. The adsorption isotherms of CO, N2 and CO2 on MOF-74(Ni) were measured, and the selectivities for CO/N2 and CO/CO2 were calculated based on ideal adsorbed solution theory (IAST). Results showed that adsorbent MOF-74(Ni) achieved superior CO adsorption capacity of 6.15 mmol·g−1 at 298 K and 0.1 MPa, and as low as 0.86 mmol·g−1 for N2. In low pressure range of 0—40 kPa, MOF-74(Ni) showed significantly higher uptake for CO than that for CO2. Moreover, IAST-predicted CO/N2 selectivity of MOF-74(Ni) is above 1000, and its CO/CO2 selectivity is in the range of 4—9. It suggests that MOF-74(Ni) is more favorable for CO adsorption than N2and CO2 adsorption.%主要研究了MOF-74(Ni)材料对CO/N2/CO2的吸附分离性能。应用水热法合成制备MOF-74(Ni),分别采用全自动表面积吸附仪、P-XRD、扫描电子显微镜对材料的孔隙结构和晶体形貌进行了表征,应用静态吸附法测定了CO、N2和CO2在MOF-74(Ni)上的吸附等温线,应用DSLF方程模拟了3种气体MOF-74(Ni)上的吸附等温线,依据IAST理论模型计算了MOF-74(Ni)对CO/N2二元混合物和CO/CO2二元混合物的吸附选择性。研究结果表明:在0.1 MPa和常温条件下,MOF-74(Ni)材料对CO吸附容量高达6.15 mmol·g−1,而相同条件下N2的吸附量只有0.86 mmol·g−1。MOF-74(Ni)在低压下(0~40 kPa)对CO的吸附量明显高于其对CO2的吸附量。应用IAST模型估算MOF-74(Ni)对二元混合物吸附选择性的结果表明:MOF-74(Ni)对CO/N2混合物的吸附选择性在1000以上;MOF-74(Ni)对 CO/CO2的吸附选择性在4~9范围,在所研究的二元气体混合物吸附体系中,MOF-74(Ni)都能优先吸附CO。

  19. A viologen-functionalized chiral Eu-MOF as a platform for multifunctional switchable material.

    Science.gov (United States)

    Li, Hai-Yang; Xu, Hong; Zang, Shuang-Quan; Mak, Thomas C W

    2016-01-11

    A novel viologen-functionalized chiral europium-based metal-organic framework (Eu-MOF) that possesses multi-switchable features including photochromism, photo-modulated luminescence, photoswitchable NLO and piezoelectric properties has been obtained for the first time. PMID:26536039

  20. Surface-modified CAU-10 MOF materials as humidity sensors: impedance spectroscopic study on water uptake.

    Science.gov (United States)

    Weiss, Alexander; Reimer, Nele; Stock, Norbert; Tiemann, Michael; Wagner, Thorsten

    2015-09-01

    Metal-organic frameworks (MOFs) are crystalline microporous materials with tunable chemical and physical properties. By combining various metal clusters with different interconnecting organic linkers, the pore structure, crystallinity, as well as the surface properties can be modified. In the present work, modification of the organic linker molecules is utilized to synthesize CAU-10 type MOFs with variable affinity of the pore surface to water. In principle, this should influence the accessibility of the pores for water vapor and therefore offer a tool to control its sorption properties. For a deeper understanding we studied the water sorption characteristics and compared the results to the conductive and dielectric properties studied by impedance spectroscopy. Spectra in a wide frequency range from 1 mHz to 1 MHz were recorded. Data analysis is performed using the Havriliak-Negami model. The MOFs are also tested as sensitive layers for capacitive humidity sensing by correlating the change in permittivity of the materials with the amount of physisorbed water. Such an MOF-based sensor was tested with respect to environmental monitoring and compared to a commonly used commercial humidity sensor. PMID:26227316

  1. An unprecedented single platform via cross-linking of zeolite and MOFs.

    Science.gov (United States)

    Lim, Dae-Woon; Lee, Heeju; Kim, Sungjune; Cho, In Hwa; Yoon, Minyoung; Choi, Yong Nam

    2016-05-21

    The unprecedented ternary nanocomposites have been synthesized as a single platform via cross-linking of two nanoporous materials, MOFs and Pt nanoparticle (NP) loaded zeolite. The heterojunction of the novel nanocomposites is anticipated to work as a chemical platform for size selective catalytic hydrogenation or deuteration of small molecules. PMID:27086901

  2. Stability of MOF-5 in a hydrogen gas environment containing fueling station impurities

    DEFF Research Database (Denmark)

    Ming, Yang; Purewal, Justin; Yang, Jun;

    2016-01-01

    hydrogen storage capacity of an exposed sample. Hydrogen chloride was observed to be the only impurity that yielded a measurable, albeit small, decrease in hydrogen capacity; no change in H2 uptake was observed for the other impurities. Post-cycling and post-storage MOF-5 samples were also analyzed using...

  3. Electronic structure of MoF6 i WF6 molecules

    International Nuclear Information System (INIS)

    Calculation of valent level ionization energies and optical transition energies in gaseous molecules of MoF6 and WF6 is given. Calculations were conducted in models of touching and covering atomic spheres. The data obtained are in good agreement with experimental values and are used for interpretation of photoelectron and optical spectra

  4. Synthesis of Zn-MOF incorporating titanium-hydrides as active sites binding H2 molecules

    Science.gov (United States)

    Kim, Jongsik; Ok Kim, Dong; Wook Kim, Dong; Sagong, Kil

    2015-10-01

    This paper describes the synthetic effort for a Zn-MOF imparting Ti-H as a preferential binding site potentially capturing H2 molecules via Kubas-type interaction. The formation mechanism of Ti-H innate to the final material was potentially demonstrated to follow a radical dissociation rather than a β-hydrogen elimination and a C-H reductive elimination.

  5. Internal excitation of UF-6 and MoF-6 ions in collisions with argon atoms

    International Nuclear Information System (INIS)

    Beams of UF-6 and MoF-6 of controlled average internal energy from 0.7 to 2.4 eV have been collided with argon at 200 eV laboratory kinetic energy. Analysis of the outgoing kinetic energy distributions shows that increased internal excitation prior to collision enhances the conversion of kinetic to internal energy. (orig.)

  6. Chemistry in confined spaces: Reactivity of the Zn-MOF-74 channels

    CERN Document Server

    Zuluaga, S; Tan, K; Arter, C A; Li, J; Chabal, I J; Thonhauser, T

    2016-01-01

    Using infrared spectroscopy combined with ab initio methods we study reactions of H$_2$O and CO inside the confined spaces of Zn-MOF-74 channels. Our results show that, once the water dissociation reaction H$_2$O$\\;\\rightarrow\\;$OH+H takes place at the metal centers, the addition of 40 Torr of CO at 200 $^{\\circ}$C starts the production of formic acid via OH+H+CO$\\;\\rightarrow\\;$HCO$_2$H. Our detailed analysis shows that the overall reaction H$_2$O+CO$\\;\\rightarrow\\;$HCO$_2$H takes place in the confinement of MOF-74 without an external catalyst, unlike the same reaction on flat surfaces. This discovery has several important consequences: It opens the door to a new set of catalytic reactions inside the channels of the MOF-74 system, it suggests that a recovery of the MOF's adsorption capacity is possible after it has been exposed to water (which in turn stabilizes its crystal structure), and it produces the important industrial feedstock formic acid.

  7. Iodine confinement into metal-organic frameworks (MOFs)-low temperature sintering glasses to form novel glass composite material (GCM) alternative waste forms.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Garino, Terry J.; Sava, Dorina Florentina

    2010-11-01

    The safe handling of reprocessed fuel addresses several scientific goals, especially when considering the capture and long-term storage of volatile radionuclides that are necessary during this process. Despite not being a major component of the off-gas, radioiodine (I{sub 2}) is particularly challenging, because it is a highly mobile gas and {sup 129}I is a long-lived radionuclide (1.57 x 10{sup 7} years). Therefore, its capture and sequestration is of great interest on a societal level. Herein, we explore novel routes toward the effective capture and storage of iodine. In particular, we report on the novel use of a new class of porous solid-state functional materials (metal-organic frameworks, MOFs), as high-capacity adsorbents of molecular iodine. We further describe the formation of novel glass-composite material (GCM) waste forms from the mixing and sintering of the I{sub 2}-containing MOFs with Bi-Zn-O low-temperature sintering glasses and silver metal flakes. Our findings indicate that, upon sintering, a uniform monolith is formed, with no evidence of iodine loss; iodine is sequestered during the heating process by the in situ formation of AgI. Detailed materials characterization analysis is presented for the GCMs. This includes powder X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), thermal analysis (thermogravimetric analysis (TGA)), and chemical durability tests including aqueous leach studies (product consistency test (PCT)), with X-ray fluorescence (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) of the PCT leachate.

  8. Iodine confinement into metal-organic frameworks (MOFs): Low temperature sintering glasses to form novel glass composite material (GCM) alternative waste forms

    International Nuclear Information System (INIS)

    The safe handling of reprocessed fuel addresses several scientific goals, especially when considering the capture and long-term storage of volatile radionuclides that are necessary during this process. Despite not being a major component of the off-gas, radioiodine (I2) is particularly challenging, because it is a highly mobile gas and 129I is a long-lived radionuclide (1.57 x 107 years). Therefore, its capture and sequestration is of great interest on a societal level. Herein, we explore novel routes toward the effective capture and storage of iodine. In particular, we report on the novel use of a new class of porous solid-state functional materials (metal-organic frameworks, MOFs), as high-capacity adsorbents of molecular iodine. We further describe the formation of novel glass-composite material (GCM) waste forms from the mixing and sintering of the I2-containing MOFs with Bi-Zn-O low-temperature sintering glasses and silver metal flakes. Our findings indicate that, upon sintering, a uniform monolith is formed, with no evidence of iodine loss; iodine is sequestered during the heating process by the in situ formation of AgI. Detailed materials characterization analysis is presented for the GCMs. This includes powder X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), thermal analysis (thermogravimetric analysis (TGA)), and chemical durability tests including aqueous leach studies (product consistency test (PCT)), with X-ray fluorescence (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) of the PCT leachate.

  9. Amine Functionalized Porous Network

    KAUST Repository

    Eddaoudi, Mohamed

    2015-05-28

    Amine groups can be introduced in porous materials by a direct (one pot) or post-synthetic modification (PSM) process on aldehyde groups, and the resulting porous materials have increased gas affinity.

  10. MOF catalysis of Fe(II)-to-Fe(III) reaction for an ultrafast and one-step generation of the Fe2O3@MOF composite and uranium(vi) reduction by iron(ii) under ambient conditions.

    Science.gov (United States)

    Xiong, Yang Yang; Li, Jian Qiang; Yan, Chang Sheng; Gao, Heng Ya; Zhou, Jian Ping; Gong, Le Le; Luo, Ming Biao; Zhang, Le; Meng, Pan Pan; Luo, Feng

    2016-08-01

    Herein, we demonstrate that Zn-MOF-74 enables the ultrafast and one-step generation of the Fe2O3@MOF composite once Zn-MOF-74 contacts with FeSO4 solution. This unique reaction can be further applied in catalysis of U(vi) reduction by Fe(ii) under ambient conditions. The results provide a highly renovated strategy for U(vi) reduction by Fe(ii) just under ambient conditions, which completely subvert all established methods about U(vi) reduction by Fe(ii) in which O2- and CO2-free conditions are absolutely required. PMID:27380820

  11. Study on preparation and characterization of MOF based lanthanide doped luminescent coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Binh, Nguyen Thanh; Tien, Dinh Manh; Giang, Lam Thi Kieu; Khuyen, Hoang Thi; Huong, Nguyen Thanh; Huong, Tran Thu; Lam, Tran Dai, E-mail: lamtd@ims.vast.ac.vn

    2014-02-14

    Coordination polymers (metal–organic frameworks or MOFs) offer the opportunity for fine-tuning the luminescence behavior because of the possibility to entrap in the network pores molecules that can influence the lanthanide (Ln) emission. In this study, Zn (II) and polycarboxylate based MOFs were first pre-formed by solvothermal method, then considered as host-matrix for in situ doping of low-input concentration of Eu{sup 3+} and Tb{sup 3+} (two most commonly used lanthanides in life science assays), and afterwards lanthanide doped luminescent materials were synthesized. Different characterizations (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS)) were carried out to confirm accordingly MOF's crystallinity, the structure and chemical composition. The study on luminescent properties of the material has revealed an efficient energy transfer from the ligand excited states to the Eu{sup 3+} and Tb{sup 3+} f-excited states. With quite low input concentrations (8–15%) of doped rare earth ions, these complexes displayed intense emissions at room temperature and proved to be good candidates for red and green emitter luminescent materials. Generally, this design concept can be extended for the preparation of other rare earth coordination polymers. - Highlights: • Synthesis of luminescent materials MOF-5/RE (RE = Eu, Tb) by solvothermal method with in situ doping of Eu{sup 3+} and Tb{sup 3+}. • MOF-5/RE with ordered structure gives strong luminescence spectra. • The design concept can be extended for the preparation of other rare earth coordination polymers.

  12. Sex-biased transcription enhancement by a 5' tethered Gal4-MOF histone acetyltransferase fusion protein in Drosophila

    Directory of Open Access Journals (Sweden)

    Belikoff Esther J

    2010-11-01

    Full Text Available Abstract Background In male Drosophila melanogaster, the male specific lethal (MSL complex is somehow responsible for a two-fold increase in transcription of most X-linked genes, which are enriched for histone H4 acetylated at lysine 16 (H4K16ac. This acetylation requires MOF, a histone acetyltransferase that is a component of the MSL complex. MOF also associates with the non-specific lethal or NSL complex. The MSL complex is bound within active genes on the male X chromosome with a 3' bias. In contrast, the NSL complex is enriched at promoter regions of many autosomal and X-linked genes in both sexes. In this study we have investigated the role of MOF as a transcriptional activator. Results MOF was fused to the DNA binding domain of Gal4 and targeted to the promoter region of UAS-reporter genes in Drosophila. We found that expression of a UAS-red fluorescent protein (DsRed reporter gene was strongly induced by Gal4-MOF. However, DsRed RNA levels were about seven times higher in female than male larvae. Immunostaining of polytene chromosomes showed that Gal4-MOF co-localized with MSL1 to many sites on the X chromosome in male but not female nuclei. However, in female nuclei that express MSL2, Gal4-MOF co-localized with MSL1 to many sites on polytene chromosomes but DsRed expression was reduced. Mutation of conserved active site residues in MOF (Glu714 and Cys680 reduced HAT activity in vitro and UAS-DsRed activation in Drosophila. In the presence of Gal4-MOF, H4K16ac levels were enriched over UAS-lacZ and UAS-arm-lacZ reporter genes. The latter utilizes the constitutive promoter from the arm gene to drive lacZ expression. In contrast to the strong induction of UAS-DsRed expression, UAS-arm-lacZ expression increased by about 2-fold in both sexes. Conclusions Targeting MOF to reporter genes led to transcription enhancement and acetylation of histone H4 at lysine 16. Histone acetyltransferase activity was required for the full transcriptional

  13. Tailored Porous Materials

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  14. Prediction of adsorption of small molecules in porous materials based on ab initio force field method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Computational prediction of adsorption of small molecules in porous materials has great impact on the basic and applied research in chemical engineering and material sciences. In this work,we report an approach based on grand canonical ensemble Monte Carlo(GCMC) simulations and ab initio force fields. We calculated the adsorption curves of ammonia in ZSM-5 zeolite and hydrogen in MOF-5(a metal-organic-framework material). The predictions agree well with experimental data. Because the predictions are based on the first principle force fields,this approach can be used for the adsorption prediction of new molecules or materials without experimental data as guidance.

  15. Synthesis and Characterization of Metal-Organic Frameworks (MOFs) for Photon Collection and Energy Transfer

    Science.gov (United States)

    So, Monica C.

    . To address problem (a), we incorporated antenna molecules (i.e. perylene diimides) to expand light collection and then transfer energy to the primary chromophores. To address problem (b), we observed that excitons can achieve up to 2,025 hops in a porphyrin-based metal-organic framework (MOF) single crystal within its 3 ns lifetime. By precisely aligning the chromophores in the MOF, we showed that long-distance exciton transport (i.e. ultra-fast, sequential hopping) was consistent with the well-established Forster theory. To address problems (c) and (d), we introduced MOF components one step at a time to optimize optical path length and crystal-thickness. This allowed us to incorporate MOFs (normally bulk crystals) into a MOF film. The approach exploited both MOF chemistry and layer-by-layer (LbL) assembly of crystalline MOFs in a highly controlled fashion on functional surfaces. We also incorporated good light-harvesting molecules as struts in MOFs to increase the visible absorption. Designing MOF-based OPVs can provide insight into solar energy conversion. This can potentially lead to much higher efficiencies, based on the simultaneous resolution of the four challenges hindering OPV performance.

  16. Multi-Column Experimental Test Bed Using CaSDB MOF for Xe/Kr Separation

    Energy Technology Data Exchange (ETDEWEB)

    Welty, Amy Keil [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, Mitchell Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, Troy Gerry [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    Processing of spent nuclear fuel produces off-gas from which several volatile radioactive components must be separated for further treatment or storage. As part of the Off-gas Sigma Team, parallel research at INL and PNNL has produced several promising sorbents for the selective capture of xenon and krypton from these off-gas streams. In order to design full-scale treatment systems, sorbents that are promising on a laboratory scale must be proven under process conditions to be considered for pilot and then full-scale use. To that end, a bench-scale multi-column system with capability to test multiple sorbents was designed and constructed at INL. This report details bench-scale testing of CaSDB MOF, produced at PNNL, and compares the results to those reported last year using INL engineered sorbents. Two multi-column tests were performed with the CaSDB MOF installed in the first column, followed with HZ-PAN installed in the second column. The CaSDB MOF column was placed in a Stirling cryocooler while the cryostat was employed for the HZ-PAN column. Test temperatures of 253 K and 191 K were selected for the first column while the second column was held at 191 K for both tests. Calibrated volume sample bombs were utilized for gas stream analyses. At the conclusion of each test, samples were collected from each column and analyzed for gas composition. While CaSDB MOF does appear to have good capacity for Xe, the short time to initial breakthrough would make design of a continuous adsorption/desorption cycle difficult, requiring either very large columns or a large number of smaller columns. Because of the tenacity with which Xe and Kr adhere to the material once adsorbed, this CaSDB MOF may be more suitable for use as a long-term storage solution. Further testing is recommended to determine if CaSDB MOF is suitable for this purpose.

  17. Interpenetration in coordination polymers: structural diversities toward porous functional materials

    Directory of Open Access Journals (Sweden)

    Ritesh Haldar

    2015-03-01

    Full Text Available Interpenetration is a natural phenomenon frequently encountered in porous coordination polymers (PCPs or metal-organic frameworks (MOFs. Traditionally interpenetration has been considered as a threat to permanent porosity and several strategies have been adopted to control the framework interpenetration. Recent literature reports have unveiled that interpenetration has paramount importance in several material properties particularly in storage and separation of small gas molecules. Such frameworks also show interesting structural flexibility based on shearing or movement of the nets and also reveals guest induced dynamic structural transformation for modulated specific functions. In this review, we will emphasize several interpenetration phenomena observed in coordination polymers, their intriguing structural aspects and fascinating material properties.

  18. Fundamental problems in porous materials: Experiments & computer simulation

    Science.gov (United States)

    Xu, Zhanping

    Porous materials have attracted massive scientific and technological interest because of their extremely high surface-to-volume ratio, molecular tunability in construction, and surface-based applications. Through my PhD work, porous materials were engineered to meet the design in selective binding, self-healing, and energy damping. For example, crystalline MOFs with pore size spanning from a few angstroms to a couple of nanometers were chemically engineered to show 120 times more efficiency in binding of large molecules. In addition, we found building blocks released from those crystals can be further patched back through a healing process at ambient and low temperatures down to -56 °C. When building blocks are replaced with graphenes, ultra-flyweight aerogels with pore size larger than 100 nm were made to delay shock waves. More stable rigid porous metal with larger pores (~um) was also fabricated, and its performance and survivability are under investigation. Aside from experimental studies, we also successfully applied numerical simulations to study the mutual interaction between the nonplanar liquid-solid interface and colloidal particles during the freezing of the colloidal suspensions. Colloidal particles can be either rejected or engulfed by the evolving interface depending on the freezing speed and strength of interface-particle interaction. Our interactive simulation was achieved by programming both simulation module and visualization module on high performance GPU devices.

  19. Direct white-light and a dual-channel barcode module from Pr(III)-MOF crystals.

    Science.gov (United States)

    Du, Bin-Bin; Zhu, Yi-Xuan; Pan, Mei; Yue, Mei-Qin; Hou, Ya-Jun; Wu, Kai; Zhang, Lu-Yin; Chen, Ling; Yin, Shao-Yun; Fan, Ya-Nan; Su, Cheng-Yong

    2015-08-14

    Direct white-light emission and further a dual-channel readable barcode module in both visible and NIR region was established by single-component homo-metallic Pr(iii)-MOF crystals for the first time. PMID:26152399

  20. Liquid-Phase Epitaxial Growth of Highly Oriented and Crystalline MOF Thin Films: Post-Synthetic Modification and Different Applications

    OpenAIRE

    Wang, Zhengbang

    2015-01-01

    The studies for this PhD thesis showed the preparation, characterization and application of new-type surface-mounted metal-organic frameworks (SURMOFs). The aims were to: (1) heteroepitaxially grow MOF-on-MOF multilayer systems with huge lattice mismatch; (2) modify azide-based SURMOFs using alkyne-azide click chemistry; (3) chemically pattern SURMOFs using postsynthetic modification (PSM); (4) engineer UHM-3 SURMOFs with quantitative Cu(I) defects using postsynthetic thermal treatment.

  1. Highly monodisperse M III-based soc -MOFs (M = in and Ga) with cubic and truncated cubic morphologies

    KAUST Repository

    Pang, Maolin

    2012-08-15

    In this work, we carry out an investigation on shape-controlled growth of In III- and Ga III-based square-octahedral metal-organic frameworks (soc-MOFs). In particular, controllable crystal morphological evolution from simple cubes to complex octadecahedra has been achieved, and resultant highly uniform crystal building blocks promise new research opportunities for preparation of self-assembled MOF materials and related applications. © 2012 American Chemical Society.

  2. Systematic modulation and enhancement of CO{sub 2} : N{sub 2} selectivity and water stability in an isoreticular series of bio-MOF-11 analogues

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Chen, De-Li; Sullivan, Jeanne E.; Kozlowski, Mark T.; Johnson, J Karl; Rosi, Nathaniel L.

    2013-02-01

    An isoreticular series of cobalt-adeninate bio-MOFs (bio-MOFs 11-14) is reported. The pores of bio-MOFs 11-14 are decorated with acetate, propionate, butyrate, and valerate, respectively. The nitrogen (N{sub 2}) and carbon dioxide (CO{sub 2}) adsorption properties of these materials are studied and compared. The isosteric heats of adsorption for CO{sub 2} are calculated, and the CO{sub 2}:N{sub 2} selectivities for each material are 10 determined. As the lengths of the aliphatic chains decorating the pores in bio-MOFs 11-14 increase, the BET surface areas decrease from 1148 m{sup 2}/g to 17 m{sup 2}/g while the CO{sub 2}:N{sub 2} selectivities predicted from ideal adsorbed solution theory at 1 bar and 273 K for a 10:90 CO{sub 2}:N{sub 2} mixture range from 73:1 for bio-MOF-11 to 123:1 for bio-MOF-12 and finally to 107:1 for bio-MOF-13. At 298 K, the selectivities are 43:1 for bio-MOF-11, 52:1 for bio-MOF-12, and 40:1 for bio-MOF-13. Additionally, it is shown that 15 bio-MOF-14 exhibits a unique molecular sieving property that allows it to adsorb CO{sub 2} but not N{sub 2} at 273 and 298 K. Finally, the water stability of bio-MOFs 11-14 increases with increasing aliphatic chain length. Bio-MOF-14 exhibits no loss of crystallinity or porosity after soaking in water for one month.

  3. A multi-material CCALE-MOF approach in cylindrical geometry

    CERN Document Server

    Friess, Marie Billaud; Galera, Stephane; Maire, Pierre-Henri; Shashkov, Mikhail

    2011-01-01

    In this paper we present recent developments concerning a Cell-Centered Arbitrary Lagrangian Eulerian (CCALE) strategy using the Moment Of Fluid (MOF) interface reconstruction for the numerical simulation of multi-material compressible fluid flows on general unstructured grids in cylindrical geometries. Especially, our attention is focused here on the following points. First, we propose a new formulation of the scheme used during the Lagrangian phase in the particular case of axisymmetric geometries. Then, the MOF method is considered for multi-interface reconstruction in cylindrical geometry. Subsequently, a method devoted to the rezoning of polar meshes is detailed. Finally, a generalization of the hybrid remapping to cylindrical geometries is presented. These explorations are validated by mean of several test cases that clearly illustrate the robustness and accuracy of the new method.

  4. Study of electronic structure and spectra of MoF6 and WF6 molecules

    International Nuclear Information System (INIS)

    Calculation of the electronic structure and spectra of MoF6 and WF6 molecules is carried out by the method of Xα scattered waves taking into account deviations of MT-potential from a real one. The calculation is carried out for ground states of the given molecules as well as for a series of transition states corresponding to ionization of 2p-levels of F-atom and to transitions with charge transfer. The calculational method used allowed to overcome largely restrictions of the traditional method of scattered waves and to reach good agreement with the experiment for the majority of spectroscopic characteristics of MoF6 and WF6 molecules

  5. Electronic and geometric structure and vibrational spectra of MoF3 and WF3 molecules

    International Nuclear Information System (INIS)

    Properties of MoF3 and WF3 molecules are studied in broad bases supplemented by d- and f-polarization functions, through the Hartree-Fock by the Meller-Plesset perturbation theory of the second order and configuration interaction method of the second order plotted on a multiconfigurational wave function obtained in approximation of the active orbitals full space. 4A2' is the main electron state of the MoF3 and WF3 molecules with geometrical nuclei configuration of the D3h symmetry. Geometrical parameters and vibrational spectrum are obtained for this state. Analysis of peculiarities of chemical bond formation is carried out and a simple model explaining the change in relative energies of electron states in the molecules series under consideration is proposed

  6. Therapeutic application of molecular adsorbents recirculating system in various pathogenic MODS/MOF patients

    Institute of Scientific and Technical Information of China (English)

    LUO Hong-tao; GUO Li-min; WU Min; LIU Quan-mei; WANG Min-min

    2005-01-01

    @@ Multiple organ dysfunction syndrome (MODS) or multiple organ failure (MOF) is a syndrome which is frequently related to shock and sepsis, and has been described as the most common cause of death in the noncoronary critical care unit. The potential pathogenesis of the septic and systemic inflammatory response syndrome (SIRS) response has been increasingly associated with the development and aggravation of MODS or MOF. And studies in this respect have also demonstrated that there is a higher risk of mortality associated with some specific organ systems when they are dysfunctional, thus leading to the failures of the liver, brain, lung, and kidney.1 The liver interacts with many other organ systems, and liver dysfunction may act collectively in the production of organ system dysfunction, thus finally ending up with MODS.2

  7. Structural and electronic properties of Li-ion battery cathode material MoF3 from first-principles

    International Nuclear Information System (INIS)

    The transition metal fluorides have been extensively investigated recently as the electrode materials with high working voltage and large capacity. The structural, electronic and magnetic properties of MoF3 are studied by the first-principles calculations within both the generalized gradient approximation (GGA) and GGA+U frameworks. Our results show that the antiferromagnetic configuration of MoF3 is more stable than the ferromagnetic one, which is consistent with experimental results. The analysis of the electronic density of states shows that MoF3 is a Mott–Hubbard insulator with a d–d type band gap, which is similar to the case of FeF3. Moreover, small spin polarizations were found on the sites of fluorine ions, which accords with a fluorine-mediated superexchange mechanism for the Mo–Mo magnetic interaction. - Graphical abstract: Deformation charge density and spin-density for MoF3 in the AF configuration. - Highlights: • The ground state of MoF3 is shown to be antiferromagnetic, in consistent with experiments. • The electronic states show that MoF3 is a Mott–Hubbard insulator with a d–d type band gap. • A fluorine-mediated super-exchange mechanism for the Mo–Mo magnetic interaction is shown

  8. Isosteric heat of hydrogen adsorption on MOFs: comparison between adsorption calorimetry, sorption isosteric method, and analytical models

    Science.gov (United States)

    Kloutse, A. F.; Zacharia, R.; Cossement, D.; Chahine, R.; Balderas-Xicohténcatl, R.; Oh, H.; Streppel, B.; Schlichtenmayer, M.; Hirscher, M.

    2015-12-01

    Isosteric heat of adsorption is an important parameter required to describe the thermal performance of adsorptive storage systems. It is most frequently calculated from adsorption isotherms measured over wide ranges of pressure and temperature, using the so-called adsorption isosteric method. Direct quantitative estimation of isosteric heats on the other hand is possible using the coupled calorimetric-volumetric method, which involves simultaneous measurement of heat and adsorption. In this work, we compare the isosteric heats of hydrogen adsorption on microporous materials measured by both methods. Furthermore, the experimental data are compared with the isosteric heats obtained using the modified Dubinin-Astakhov, Tóth, and Unilan adsorption analytical models to establish the reliability and limitations of simpler methods and assumptions. To this end, we measure the hydrogen isosteric heats on five prototypical metal-organic frameworks: MOF-5, Cu-BTC, Fe-BTC, MIL-53, and MOF-177 using both experimental methods. For all MOFs, we find a very good agreement between the isosteric heats measured using the calorimetric and isosteric methods throughout the range of loading studied. Models' prediction on the other hand deviates from both experiments depending on the MOF studied and the range of loading. Under low-loadings of less than 5 mol kg-1, the isosteric heat of hydrogen adsorption decreases in the order Cu-BTC > MIL-53 > MOF-5 > Fe-BTC > MOF-177. The order of isosteric heats is coherent with the strength of hydrogen interaction revealed from previous thermal desorption spectroscopy measurements.

  9. Encapsulation of curcumin in cyclodextrin-metal organic frameworks: Dissociation of loaded CD-MOFs enhances stability of curcumin.

    Science.gov (United States)

    Moussa, Zeinab; Hmadeh, Mohamad; Abiad, Mohamad G; Dib, Omar H; Patra, Digambara

    2016-12-01

    Curcumin has been successfully encapsulated in cyclodextrin-metal organic frameworks (CD-MOFs) without altering their crystallinity. The interaction between curcumin and CD-MOFs is strong through hydrogen bond type interaction between the OH group of cyclodextrin of CD-MOFs and the phenolic hydroxyl group of the curcumin. Interestingly, dissolving the curcumin loaded CD-MOFs crystals in water results in formation of a unique complex between curcumin, γCD and potassium cations. In fact, the initial interaction between curcumin and CD-MOF is crucial for the formation of the latter. This new complex formed in alkaline media at pH 11.5 has maximum absorbance at 520nm and emittance at 600nm. Most importantly, the stability of curcumin in this complex was enhanced by at least 3 orders of magnitude compared to free curcumin and curcumin:γ-CD at pH 11.5. These results suggest a promising benign system of CD-MOFs, which can be used to store and stabilize curcumin for food applications. PMID:27374559

  10. Polymer-metal organic frameworks (MOFs) mixed matrix membranes for gas separation applications

    OpenAIRE

    Shahid, Salman

    2015-01-01

    The performance of polymeric membranes is often limited by a trade-off between membrane permeability and selectivity, the so-called Robeson upper bound. Additionally, in high pressure CO2 capture applications, excessive swelling of the polymer membrane often leads to plasticization resulting in decreased separation performances. The main goal of this work was to develop high-performance polymeric Mixed Matrix Membranes (MMMs) with Metal Organic Frameworks (MOFs) as the inorganic additive for ...

  11. Theoretical model estimation of guest diffusion in Metal-Organic Frameworks (MOFs)

    KAUST Repository

    Zheng, Bin

    2015-08-11

    Characterizing molecule diffusion in nanoporous matrices is critical to understanding the novel chemical and physical properties of metal-organic frameworks (MOFs). In this paper, we developed a theoretical model to fastly and accurately compute the diffusion rate of guest molecules in a zeolitic imidazolate framework-8 (ZIF-8). The ideal gas or equilibrium solution diffusion model was modified to contain the effect of periodical media via introducing the possibility of guests passing through the framework gate. The only input in our model is the energy barrier of guests passing through the MOF’s gate. Molecular dynamics (MD) methods were employed to gather the guest density profile, which then was used to deduce the energy barrier values. This produced reliable results that require a simulation time of 5 picoseconds, which is much shorter when using pure MD methods (in the billisecond scale) . Also, we used density functional theory (DFT) methods to obtain the energy profile of guests passing through gates, as this does not require specification of a force field for the MOF degrees of freedom. In the DFT calculation, we only considered one gate of MOFs each time; as this greatly reduced the computational cost. Based on the obtained energy barrier values we computed the diffusion rate of alkane and alcohol in ZIF-8 using our model, which was in good agreement with experimental test results and the calculation values from standard MD model. Our model shows the advantage of obtaining accurate diffusion rates for guests in MOFs for a lower computational cost and shorter calculation time. Thus, our analytic model calculation is especially attractive for high-throughput computational screening of the dynamic performance of guests in a framework.

  12. The meaning of food (MOF): The development of a new measurement tool

    OpenAIRE

    Ogden, J; Liakopoulou, E; Antilliou, G; Gough, G.

    2012-01-01

    This paper aimed to develop a reliable measurement tool to evaluate the meanings of food that could be used in both practice and research and to examine possible gender differences. A new meaning of food questionnaire (MOF) was refined across two studies (study 1, n = 451 and study 2, n = 170). The final questionnaire consisted of 25 items and 8 reliable subscales: food and sex, emotional regulation, treat, guilt, social interaction, control over life, control over food, family. The new Meani...

  13. Thermodynamically Guided Synthesis of Mixed-Linker Zr-MOFs with Enhanced Tunability.

    Science.gov (United States)

    Yuan, Shuai; Qin, Jun-Sheng; Zou, Lanfang; Chen, Ying-Pin; Wang, Xuan; Zhang, Qiang; Zhou, Hong-Cai

    2016-05-25

    Guided by thermodynamics, we have synthesized two mixed-linker zirconium-based metal-organic frameworks (Zr-MOFs), namely, PCN-133 and PCN-134. Both of them possess a layer-pillar structure, in which the connection between Zr6 clusters and primary BTB linkers form a (3,6)-connected kdg layer that is further extended into 3D frameworks by auxiliary DCDPS/TCPP linkers (BTB = benzene tribenzoate, DCDPS = 4,4'-dicarboxydiphenyl sulfone, TCPP = tetrakis(4-carboxyphenyl)porphyrin). PCN-134 demonstrates high porosity (N2 uptake of 717 cm(3)·g(-1) and BET surface area of 1946 cm(2)·g(-1)) and excellent chemical stability in aqueous solutions with pH values ranging from 0 to 13. More importantly, PCN-134 tolerates the partial absence of auxiliary linkers leading to structural defects during the assembly process while preserving its framework integrity. Furthermore, the defect density can be systematically controlled by tuning the occupancy of the auxiliary linker, which in turn affects the MOF properties. For instance, the dichromate uptake of PCN-134 is tuned by adjusting the BTB/TCPP ratios, which gives rise to an efficient dichromate absorbent when the TCPP molar ratio in linkers is set as 22%. In addition, the photocatalytic reduction of Cr(VI) in aqueous solution was also performed by PCN-134-22%TCPP which exhibits excellent catalytic activity. This work not only opens up a new synthetic route toward mixed-linker MOFs, but also provides tunable control of MOF defects and, in turn, the properties. PMID:27151517

  14. Phase equilibria in the system MoCl5-MoF5

    International Nuclear Information System (INIS)

    Phase equilibria in system MoCl5-MoF5 are studied using the DTA and visual-polythermal methods, as well as roentgenography. The system is characterized by the formation of incongruent MoCl4F and congruent compounds MoCl3F2, MoCl2F3, MoClF4 and also by the presence of stable and metastable equilibria

  15. Spectrometric analysis of a gas mixture of UF6, MoF6, and WF6

    International Nuclear Information System (INIS)

    A device for filling a gas cell was developed for the measurement of the infrared spectra of binary and ternary mixtures of UF6 with WF6 and MoF6. Suitable analytical bands were chosen and the analysis was tested by artificial mixtures within the pressure range of 3.5-10 kPa. The mean error in determining a component in the binary mixture was 5-10 relative %. (author)

  16. A study on metal organic framework (MOF-177) synthesis, characterization and hydrogen adsorption -desorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Viditha, V.; Venkateswer Rao, M.; Srilatha, K.; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally, Hyderabad-500 085, A.P. (India); Yerramilli, Anjaneyulu [Director, TLGVRC, JSU Box 18739, JSU, Jackson, MS 32917-0939 (United States)

    2013-07-01

    Hydrogen has long been considered to be an ideal alternative to fossil-fuel systems and much work has now been done on its storage. There are four main methods of hydrogen storage: as a liquid; as compressed hydrogen; in the form of metal hydrides; and by physisorption. Among all the materials metal organic frameworks (MOFs) are considered to have desirable properties like high porosity, pore volume and high thermal stability. MOF-177 is considered to be an ideal storage material. In this paper we study about its synthesis and hydrogen storage capacities of MOF-177 at different pressures ranging from 25, 50, 75 and 100 bar respectively. The obtained samples are characterized by XRD, BET and SEM. The recorded results show that the obtained hydrogen capacity is 1.1, 2.20, 2.4 and 2.80 wt%. The desorption capacity is 0.9, 2.1, 2.37 and 2.7 wt% at certain temperatures like 373 K.

  17. A study on metal organic framework (MOF-177 synthesis, characterization and hydrogen adsorption -desorption cycles

    Directory of Open Access Journals (Sweden)

    V.Viditha, M.Venkateswer Rao, K.Srilatha11, V.Himabindu, Anjaneyulu Yerramilli

    2013-01-01

    Full Text Available Hydrogen has long been considered to be an ideal alternative to fossil-fuel systems and much work has now been done on its storage. There are four main methods of hydrogen storage: as a liquid; as compressed hydrogen; in the form of metal hydrides; and by physisorption. Among all the materials metal organic frameworks (MOFs are considered to have desirable properties like high porosity, pore volume and high thermal stability. MOF-177 is considered to be an ideal storage material. In this paper we study about its synthesis and hydrogen storage capacities of MOF-177 at different pressures ranging from 25, 50, 75 and 100 bar respectively. The obtained samples are characterized by XRD, BET and SEM. The recorded results show that the obtained hydrogen capacity is 1.1, 2.20, 2.4 and 2.80 wt%. The desorption capacity is 0.9, 2.1, 2.37 and 2.7 wt% at certain temperatures like 373 K.

  18. Matrix infrared spectra of HCl complexes with UF6, WF6, and MoF6

    International Nuclear Information System (INIS)

    HCl complexes with UF6, WF6, and MoF6 were prepared in solid argon at 12 K. The FTIR spectrum of UF6/HCl contained a doublet at 2850.6 and 2849.7 cm-1 due to the hydrogen-bonded UF6-HCl complex. In contrast, the HCl interaction with WF6, as well as MoF6 produced two distinctly different 1:1 complexes. The 2862.1-cm-1 absorption due to the antihydrogen-bonded complex, WF6-ClH, was slightly more intense than the 2866.2 cm-1 absorption due to the antihydrogen-bonded complex, WF6-ClH, was slightly more intense than the 2866.2-cm-1 absorption of the hydrogen-bonded complex, WF6-HCl. The frequencies and relative intensities of the absorptions for the MoF6 complexes with HCl were very similar to those of their WF6 counterparts

  19. Thermodynamics of hydrogen adsorption in MOF-177 at low temperatures: measurements and modelling

    International Nuclear Information System (INIS)

    Hydrogen adsorption measurements and modelling for the Zn-based microporous metal-organic framework (MOF) Zn4O(1,3,5-benzenetribenzoate)2, MOF-177, were performed over the 50-77 K and 0-40 bar ranges. The maximum excess adsorption measured under these conditions varies over about 105-70 mg g-1. An analysis of the isotherms near saturation shows that hydrogen is ultimately adsorbed in an incompressible phase whose density is comparable to that of the bulk liquid. These liquid state properties observed under supercritical conditions reveal a remarkable effect of nanoscale confinement. The entire set of adsorption isotherms can be well described using a micropore filling model. The latter is used, in particular, to determine the absolute amounts adsorbed and the adsorption enthalpy. When expressed in terms of absolute adsorption, the isotherms show considerable hydrogen storage capacities, reaching up to 125 mg g-1 at 50 K and 25 bar. The adsorption enthalpies are calculated as a function of fractional filling and range from 3 to 5 kJ mol-1 in magnitude, in accordance with physisorption. These results are discussed with respect to a similar analysis performed on another Zn-based MOF, Zn4O(1,4-benzenedicarboxylate)3, IRMOF-1, presented recently. It is found that both materials adsorb hydrogen by similar mechanisms.

  20. Synthesis of magnetic metal-organic framework (MOF) for efficient removal of organic dyes from water

    Science.gov (United States)

    Zhao, Xiaoli; Liu, Shuangliu; Tang, Zhi; Niu, Hongyun; Cai, Yaqi; Meng, Wei; Wu, Fengchang; Giesy, John P.

    2015-07-01

    A novel, simple and efficient strategy for fabricating a magnetic metal-organic framework (MOF) as sorbent to remove organic compounds from simulated water samples is presented and tested for removal of methylene blue (MB) as an example. The novel adsorbents combine advantages of MOFs and magnetic nanoparticles and possess large capacity, low cost, rapid removal and easy separation of the solid phase, which makes it an excellent sorbent for treatment of wastewaters. The resulting magnetic MOFs composites (also known as MFCs) have large surface areas (79.52 m2 g-1), excellent magnetic response (14.89 emu g-1), and large mesopore volume (0.09 cm3 g-1), as well as good chemical inertness and mechanical stability. Adsorption was not drastically affected by pH, suggesting π-π stacking interaction and/or hydrophobic interactions between MB and MFCs. Kinetic parameters followed pseudo-second-order kinetics and adsorption was described by the Freundlich isotherm. Adsorption capacity was 84 mg MB g-1 at an initial MB concentration of 30 mg L-1, which increased to 245 mg g-1 when the initial MB concentration was 300 mg L-1. This capacity was much greater than most other adsorbents reported in the literature. In addition, MFC adsorbents possess excellent reusability, being effective after at least five consecutive cycles.

  1. Reticular Synthesis of a Series of HKUST-like MOFs with Carbon Dioxide Capture and Separation.

    Science.gov (United States)

    He, Hongming; Sun, Fuxing; Ma, Shengqian; Zhu, Guangshan

    2016-09-01

    We reported a series of HKUST-like MOFs based on multiple copper-containing secondary building units (SBUs). Compound 1 is constructed by two SBUs: Cu2(CO2)4 paddle-wheel SBUs and Cu2I2 dimer SBUs. Compound 2 has Cu2(CO2)4 paddle-wheel SBUs and Cu4I4 SBUs. Furthermore, compound 3 possesses Cu2(CO2)4 paddle-wheel SBUs, Cu2I2 dimer SBUs, and Cu(CO2)4 SBUs. These compounds are promising materials for CO2 capture and separation, because they all display commendable adsorption of CO2 and high selectivity for CO2 over CH4 and N2. It is worthy to note that compound 1 exhibits the highest Brunauer-Emmett-Teller surface area (ca. 901 m(2) g(-1)) among the MOF materials based on CuxIy SBUs. In addition, compound 3 is the first case that three copper SBUs coexist in MOFs. PMID:27556744

  2. Highly stable and sensitive LnMOF ratiometric thermometers constructed with mixed ligands.

    Science.gov (United States)

    Wei, Yongqin; Sa, Rongjian; Li, Qiaohong; Wu, Kechen

    2015-02-21

    The mixed-lanthanide metal-organic frameworks (M'LnMOFs) applied for accurate, non-invasive and self-reference temperature measurements have been only recently recognized. It is a great challenge for chemists to fulfil the requirements of a thermostable structure, intense luminescence and high temperature sensitivity on one LnMOF ratiometric thermometer for thermometric applications. By choosing 2,4-(2,2':6',2''-terpyridin-4'-yl)-benzenedisulfonic acid (H2DSTP) as the first ligand and changing the ancillary ligand to oxalic acid (OA) or 1,4-benzene dicarboxylic acid (BDC), we have successfully developed two types of highly stable and sensitive thermometers [Tb1-xEux(OA)0.5(DSTP)]·3H2O and [Tb1-xEux(BDC)0.5(DSTP)]·2H2O (x = 0.01, 0.02) that in addition exhibit brilliant luminescence over a wide temperature range, providing a new strategy to explore luminescence-based M'LnMOF thermometers. PMID:25566973

  3. Role of histone acetyltransferase MOF in the pathogenesis of multiple sclerosis%组蛋白乙酰转移酶 MOF 在多发性硬化发病机制中的作用

    Institute of Scientific and Technical Information of China (English)

    关景云; 杨阳; 邱春红; 李相芝

    2016-01-01

    目的:探讨实验性自身免疫性脑脊髓炎(EAE)小鼠发病高峰期、缓解期 Treg 细胞和组蛋白乙酰转移酶MOF 表达的变化情况,以及 MOF 对 EAE 发病机制的影响。方法将20只体质量相近的6~8周龄 C57BL/6雌鼠随机分为两组,EAE 组第0天腹股沟处皮下注射200μg MOG35-55,对照组注射等量弗氏完全佐剂,两组均腹腔注射200 ng百日咳毒素,第2天腹腔注射200 ng 百日咳毒素。取 EAE 组不同发病时期和对照组小鼠的脾脏组织。Western blotting 法检测 MOF、FOXP3和 H4K16ac 蛋白的表达情况;qRT-PCR 检测脾脏组织中 MOF、FOXP3、TLRS mRNA 的表达水平;蛋白质免疫共沉淀(CoIP)法检测 MOF 与 FOXP3在脾脏组织中有无相互作用;染色质免疫共沉淀(ChIP-qPCR)法检测 MOF 的下游靶基因;在 HCT116细胞中过表达 MOF 后检测 FOXP3、TLRS 表达的变化情况。结果EAE 组脾脏中的 MOF 及 FOXP3蛋白表达水平显著高于对照组;EAE 组小鼠脾脏中 MOF、FOXP3、IL17、TLR4、TLR5、TLR6、TLR7、TLR9 mRNA 水平显著高于对照组(P <0.05);MOF 与 FOXP3在脾脏组织中结合并有相互作用;脾脏组织中,MOF 与 FOXP3、TLR3、TLR4、TLR5、TLR6、SMAD2、SMAD3和 RoRγt 启动子结合;MOF过表达后,TLR4和 FOXP3表达量增加(P <0.05)。结论MOF 通过与 FOXP3相互作用,抑制 EAE 的发生。%Objective To investigate the activities of Treg cells and the expression of MOF in the peak and remission periods of experimental allergic encephalomyelitis(EAE)mice and the impact of MOF on the pathogenesis of EAE. Methods On Day 0,twenty 6-8 week old C57BL/6 female mice of similar weight were subcutaneously injected with 200 μg MOG35-55 or complete freund’s adjuvant (CFA)and then intraperitoneally injected with 200 ng pertussis toxin. On Day 2,the above three mice were intraperitoneally injected with 200 ng pertussis toxin.The spleen tissues of the EAE

  4. Functionalized ultra-porous titania nanofiber membranes as nuclear waste separation and sequestration scaffolds for nuclear fuels recycle.

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Haiqing; Bell, Nelson Simmons; Cipiti, Benjamin B.; Lewis, Tom Goslee,; Sava, Dorina Florentina; Nenoff, Tina Maria

    2012-09-01

    Advanced nuclear fuel cycle concept is interested in reducing separations to a simplified, one-step process if possible. This will benefit from the development of a one-step universal getter and sequestration material so as a simplified, universal waste form was proposed in this project. We have developed a technique combining a modified sol-gel chemistry and electrospinning for producing ultra-porous ceramic nanofiber membranes with controllable diameters and porous structures as the separation/sequestration materials. These ceramic nanofiber materials have been determined to have high porosity, permeability, loading capacity, and stability in extreme conditions. These porous fiber membranes were functionalized with silver nanoparticles and nanocrystal metal organic frameworks (MOFs) to introduce specific sites to capture gas species that are released during spent nuclear fuel reprocessing. Encapsulation into a durable waste form of ceramic composition was also demonstrated.

  5. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    Energy Technology Data Exchange (ETDEWEB)

    Das, Atanu K.; Vemuri, Venkata Rama Ses; Kutnyakov, Igor V.; McGrail, B. Peter; Motkuri, Radha K.

    2016-06-16

    Vapor-assisted drygel synthesis of MOF-74 structure, specifically NiMOF-74 from its synthetic precursors, was conducted with high yield and improved performance showing promise for gas (CO2) and water adsorption applications. Unlike conventional synthesis, which takes 72 h, this kinetic study showed that NiMOF-74 forms within 12 h under drygel conditions with similar performance characteristics and exhibits the best performance characteristics after 48 h of heating.

  6. Mechanisms of Heat Transfer in Porous Crystals Containing Adsorbed Gases: Applications to Metal-Organic Frameworks

    Science.gov (United States)

    Babaei, Hasan; Wilmer, Christopher E.

    2016-01-01

    We have studied the mechanisms of heat transfer in a porous crystal-gas mixture system, motivated by the not insignificant challenge of quickly dissipating heat generated in metal-organic frameworks (MOFs) due to gas adsorption. Our study reveals that the thermal conductance of the system (crystal and gas) is dominated by lattice thermal conductivity in the crystal, and that conductance is reduced as the concentration of gas in the pores increases. This mechanism was observed from classical molecular simulations of a monatomic gas in an idealized porous crystal structure. We show that the decreased conductivity associated with increased gas concentration is due to phonon scattering in the crystal due to interactions with gas molecules. Calculations of scattering rates for two phonon modes reveal that scattering of the lowest frequency mode scales linearly with gas density. This result suggests that the probability of a phonon-gas collision is simply proportional to the number of gas molecules in the pore.

  7. Probing the Structure, Stability and Hydrogen Adsorption of Lithium Functionalized Isoreticular MOF-5 (Fe, Cu, Co, Ni and Zn by Density Functional Theory

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Kawazoe

    2009-04-01

    Full Text Available Li adsorption on isoreticular MOFs with metal Fe, Cu, Co, Ni and Zn was studied using density function theory. Li functionalization shows a considerable structural change associated with a volume change in isoreticular MOF-5 except for the Zn metal center. Hydrogen binding energies on Li functionalized MOFs are seen to be in the range of 0.2 eV, which is the desired value for an ideal reversible storage system. This study has clearly shown that Li doping is possible only in Zn-based MOF-5, which would be better candidate to reversibly store hydrogen.

  8. Hierarchical Porous Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grote, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-07

    Materials Design is often at the forefront of technological innovation. While there has always been a push to generate increasingly low density materials, such as aero or hydrogels, more recently the idea of bicontinuous structures has gone more into play. This review will cover some of the methods and applications for generating both porous, and hierarchically porous structures.

  9. Convection in porous media

    CERN Document Server

    Bejan, A

    2006-01-01

    Provides an introduction to convection in porous media, such as fibrous insulation, geological strata, and catalytic reactors. This third edition covers ""designed"" porous media, the theory of deformable media, modeling viscous dissipation in hyperporous media, and more. It is useful for researchers, practicing engineers and students.

  10. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1995-08-01

    We have studied a novel extrinsic gettering method that utilizes the very large surface areas, produced by porous silicon etch on both front and back surfaces of the silicon wafer, as gettering sites. In this method, a simple and low-cost chemical etching is used to generate the porous silicon layers. Then, a high-flux solar furnace (HFSF) is used to provide high-temperature annealing and the required injection of silicon interstitials. The gettering sites, along with the gettered impurities, can be easily removed at the end the process. The porous silicon removal process consists of oxidizing the porous silicon near the end the gettering process followed by sample immersion in HF acid. Each porous silicon gettering process removes up to about 10 {mu}m of wafer thickness. This gettering process can be repeated so that the desired purity level is obtained.

  11. Size- and shape-controlled synthesis of hexagonal bipyramidal crystals and hollow self-assembled Al-MOF spheres

    KAUST Repository

    Sarawade, Pradip

    2013-11-25

    We report an efficient protocol for the synthesis of monodisperse crystals of an aluminum (Al)-based metal organic framework (MOF) while obtaining excellent control over the size and shape solely by tuning of the reaction parameters without the use of a template or structure-directing agent. The size of the hexagonal crystals of the Al-MOF can be selectively varied from 100 nm to 2000 nm by simply changing the reaction time and temperature via its nucleation-growth mechanism. We also report a self-assembly phenomenon, observed for the first time in case of Al-MOF, whereby hollow spheres of Al-MOF were formed by the spontaneous organization of triangular sheet building blocks. These MOFs showed broad hysteresis loops during the CO2 capture, indicating that the adsorbed CO2 is not immediately desorbed upon decreasing the external pressure and is instead confined within the framework, which allows for the capture and subsequent selective trapping of CO2 from gaseous mixtures. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Surfactant-thermal method to synthesize a new Zn(II)-trimesic MOF with confined Ru(bpy)32+ complex

    International Nuclear Information System (INIS)

    A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy)32+ (RuBpy) complex by using surfactant PEG 400 as reaction medium. The RuBpy molecules were encapsulated between the 2-D sheets in ZJU-100. ZJU-100 showed bathochromic shift in the steady-state emission spectrum and increased emission lifetimes relative to RuBpy molecules. The extended lifetime is attributed to the reduced nonradiative decay rate due to the stabilization of RuBpy within the rigid MOF framework. These results represent the first example of MOF with confined complex synthesized by surfactant, indicating that the surfactant-thermal method could offer exciting opportunities for preparing new MOFs host/guest materials with novel structures and interesting luminescent properties. - Graphical abstract: A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy)32+ (RuBpy) complex by using surfactant PEG 400 as reaction medium. - Highlights: • Surfactant-thermal synthesis of crystalline metal-organic framework host/guest materials. • RuBpy molecules were encapsulated between the 2-D sheets of MOFs. • Extended lifetime is observed due to the stabilization of RuBpy within the rigid MOF framework

  13. Shape of the hydrogen adsorption regions of MOF-5 and its impact on the hydrogen storage capacity

    Science.gov (United States)

    Cabria, I.; López, M. J.; Alonso, J. A.

    2008-11-01

    The adsorption of molecular hydrogen on a metal-organic framework (MOF) material, MOF-5, has been studied using the density-functional formalism. The calculated potential-energy surface shows that there are two main adsorption regions: both near the OZn4 oxide cores at the vertices of the cubic skeleton of MOF-5. The adsorption energies in those regions are between 100 and 130 meV/molecule. Those adsorption regions have the shape of long, wide, and deep connected trenches and passage of the molecule between regions needs to surpass small barriers of 30-50 meV. The shape of these regions, and not only the presence of metal atoms, explains the large storage capacity measured for MOF-5. The elongated shape explains why some authors have previously identified only one type of adsorption site, associated to the Zn oxide core, and others identified two or three sites. One should consider adsorption regions rather than adsorption sites. A third region of adsorption is near the benzenic rings of the MOF-5. We have also analyzed the possibility of dissociative chemisorption. The chemisorption energy with respect to two separated H atoms is 1.33 eV/H atom; but, since dissociating the free molecule costs 4.75 eV, the physisorbed H2 molecule is more stable than the dissociated chemisorbed state by about 2 eV. Dissociation of the adsorbed molecule costs less energy, but the dissociation barrier is still high.

  14. Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction

    KAUST Repository

    Xue, Dong-Xu

    2015-03-31

    Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e. Eu3+, Tb3+ and Y3+) fcu metal‒organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cut-off ideal for selective adsorption kinetics separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in-situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the RE-fcu-MOF plat-form, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded nota-ble gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol and butanol/water pair systems.

  15. Synthesis of Zn-MOF incorporating titanium-hydrides as active sites binding H{sub 2} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongsik, E-mail: jkim40@nd.edu [Department of Chemical and Biomolecular Engineering, University of Notre Dame, 182, Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Ok Kim, Dong; Wook Kim, Dong; Sagong, Kil [Hanwha Chemical Research & Development Center, 6, Shinseong-dong, Yuseong-gu, Daejeon 305-804 (Korea, Republic of)

    2015-10-15

    This paper describes the synthetic effort for a Zn-MOF imparting Ti-H as a preferential binding site potentially capturing H{sub 2} molecules via Kubas-type interaction. The formation mechanism of Ti-H innate to the final material was potentially demonstrated to follow a radical dissociation rather than a β-hydrogen elimination and a C-H reductive elimination. - Graphical abstract: This study details the synthesis and the formation mechanism of Zn-MOF adsorbent site-isolating TiH{sub 3} that can potentially capture H{sub 2} molecules via Kubas-binding mechanism. - Highlights: • OH-functionalized Zn-MOF was employed as a reactive template to site-isolate TiH{sub 3}. • This MOF was post-synthetically modified using a tetracyclohexyl titanium (IV). • This intermediate was hydrogenolyzed to change ligand from cyclohexyl to hydride. • Formation mechanism of TiH{sub 3} was investigated via two control GC–MS experiments. • Final Zn-MOF potentially site-isolating TiH{sub 3} species was used as a H{sub 2} adsorbent.

  16. Biocompatible Zr-based nanoscale MOFs coated with modified poly(ε-caprolactone) as anticancer drug carriers.

    Science.gov (United States)

    Filippousi, Maria; Turner, Stuart; Leus, Karen; Siafaka, Panoraia I; Tseligka, Eirini D; Vandichel, Matthias; Nanaki, Stavroula G; Vizirianakis, Ioannis S; Bikiaris, Dimitrios N; Van Der Voort, Pascal; Van Tendeloo, Gustaaf

    2016-07-25

    Nanoscale Zr-based metal organic frameworks (MOFs) UiO-66 and UiO-67 were studied as potential anticancer drug delivery vehicles. Two model drugs were used, hydrophobic paclitaxel and hydrophilic cisplatin, and were adsorbed onto/into the nano MOFs (NMOFs). The drug loaded MOFs were further encapsulated inside a modified poly(ε-caprolactone) with d-α-tocopheryl polyethylene glycol succinate polymeric matrix, in the form of microparticles, in order to prepare sustained release formulations and to reduce the drug toxicity. The drugs physical state and release rate was studied at 37°C using Simulated Body Fluid. It was found that the drug release depends on the interaction between the MOFs and the drugs while the controlled release rates can be attributed to the microencapsulated formulations. The in vitro antitumor activity was assessed using HSC-3 (human oral squamous carcinoma; head and neck) and U-87 MG (human glioblastoma grade IV; astrocytoma) cancer cells. Cytotoxicity studies for both cell lines showed that the polymer coated, drug loaded MOFs exhibited better anticancer activity compared to free paclitaxel and cisplatin solutions at different concentrations. PMID:27235556

  17. Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction.

    Science.gov (United States)

    Xue, Dong-Xu; Belmabkhout, Youssef; Shekhah, Osama; Jiang, Hao; Adil, Karim; Cairns, Amy J; Eddaoudi, Mohamed

    2015-04-22

    Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e., Eu(3+), Tb(3+), and Y(3+)) fcu metal-organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cutoff, ideal for selective adsorption kinetics based separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the first RE-fcu-MOF platform, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded notable gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol, and butanol/water pair systems. PMID:25825923

  18. Quest for highly porous metal-metalloporphyrin framework based upon a custom-designed octatopic porphyrin ligand

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi-Sen; Chrzanowski, Matthew; Kim, Chungsik; Gao, Wen-Yang; Wojtas, Lukasz; Chen, Yu-Sheng; Zhang, X Peter; Ma, Shengqian [USF; (UC)

    2012-12-13

    A porous metal-metalloporphyrin framework, MMPF-2, has been constructed from a custom-designed octatopic porphyrin ligand, tetrakis(3,5-dicarboxyphenyl)porphine, that links a distorted cobalt trigonal prism secondary building unit. MMPF-2 possesses permanent microporosity with the highest surface area of 2037 mg2 g-1 among reported porphyrin-based MOFs, and demonstrates a high uptake capcity of 170 cm3 g-1 CO2 at 273 K and 1 bar.

  19. Three novel indium MOFs derived from dicarboxylate ligands: Syntheses, structures and photoluminescent properties

    International Nuclear Information System (INIS)

    The self-assembly of InCl3 with 1,4-phenylenediacetic acid (1,4-H2pda), 1,3-benzendicarboxylic acid (1,3-H2bdc) and 1,4-cyclohexanedicarboxylic acid (1,4- H2chdc) generates three new In(III) MOFs, (Me2NH2)[In(cis-1,4-pda)2] (1), HIn(1,3-bdc)2·2DMF (2) and In(OH)(trans-1,4-chdc) (3) (Me2NH=dimethylamine, DMF=N, N’-dimethylformamide). Compound 1 displays a novel 1D no-planar double chain. Although a mixture of cis- and trans-1,4-H2pda was used, the product of compound 1 is a single phase with only cis-pda2− ligands. Compound 2 possesses a 2D square lattice with sql topology. Interestingly, in compound 2, the 4-connected building unit containing InO6 octahedron is firstly occurred in In-MOFs. Compound 3 is built up from the infinite metal-oxide chains cross-linked by trans-1,4-chdc2− to form 3D framework with rhombus-shaped channels. Furthermore, compounds 1–3 present intense solid-state fluorescent emissions at room temperature. - Graphical abstract: Three new In-MOFs based on different dicaboxylate acids display 1D chain, 2D layer and 3D open-framework, respectively and show strong luminescence emissions at room temperature. Highlights: ► Three new indium metal-organic frameworks have been solvothermal synthesized. ► The structural variation is attributed to the diverse coordination modes of ligands. ► Compounds 1–3 exhibit 1D double chain, 2D layer and 3D open-framework, respectively. ► These compounds exhibit strong solid-state luminescence emission at room temperature.

  20. Fabricating porous silicon carbide

    Science.gov (United States)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1994-01-01

    The formation of porous SiC occurs under electrochemical anodization. A sample of SiC is contacted electrically with nickel and placed into an electrochemical cell which cell includes a counter electrode and a reference electrode. The sample is encapsulated so that only a bare semiconductor surface is exposed. The electrochemical cell is filled with an HF electrolyte which dissolves the SiC electrochemically. A potential is applied to the semiconductor and UV light illuminates the surface of the semiconductor. By controlling the light intensity, the potential and the doping level, a porous layer is formed in the semiconductor and thus one produces porous SiC.

  1. The relevance of metal organic frameworks (MOFs) in inorganic materials chemistry

    Indian Academy of Sciences (India)

    Srinivasan Natarajan; Partha Mahata; Debajit Sarma

    2012-03-01

    The metal organic frameworks (MOFs) have evolved to be an important family and a corner stone for research in the area of inorganic chemistry. The progress made since 2000 has attracted researchers from other disciplines to actively engage themselves in this area. This cooperative synergy of different scientific believes have provided important edge and spread to the chemistry of metal-organic frameworks. The ease of synthesis coupled with the observation of properties in the areas of catalysis, sorption, separation, luminescence, bioactivity, magnetism, etc., are a proof of this synergism. In this article, we present the recent developments in this area.

  2. Preparation of Zeolitic Imidazolate Framework-8 (ZIF-8) Membrane on Porous Polymeric Support via Contra-Diffusion Method

    KAUST Repository

    Tan, Xiaoyu

    2016-05-18

    In the last decade, many attempts were made to put metal organic frameworks (MOFs) in industrial applications, but most of these efforts weren’t successfully. As one of the few MOFs produced on industrial scale, ZIF-8 has interesting pore size, huge internal surface area and great thermal and chemical stability. Therefore, ZIF-8 might become the first MOF, which will be applied in industrial separation processes. In this thesis, a synthesis study is presented, which leads to a cheap and convenient way to
fabricate defect-free and thin ZIF-8 membranes on porous polymeric supports showing high selectivity and high gas permeance. The ZIF-8 layers were produced via a contra-diffusion method. Several polymeric membranes were employed as support in this study, such as PAN, PEI, PSU, PA and PTSC. We studied the influence of the polymeric support properties for the ZIF-8 membrane preparation and optimized the ZIF-8 preparation conditions. The ZIF-8 membranes were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). For gas permeation test, we chose a Wicke-Kallenbach apparatus to measure membrane’s gas permeance and selectivity. One of the best ZIF-8 membranes exhibited a hydrogen permeance of 3.45 × 10-8 mol m-2 s-1 Pa-1 and
an ideal selectivity of hydrogen over propane of about 500.

  3. Cation Exchange Strategy for the Encapsulation of a Photoactive CO-Releasing Organometallic Molecule into Anionic Porous Frameworks.

    Science.gov (United States)

    Carmona, Francisco J; Rojas, Sara; Sánchez, Purificación; Jeremias, Hélia; Marques, Ana R; Romão, Carlos C; Choquesillo-Lazarte, Duane; Navarro, Jorge A R; Maldonado, Carmen R; Barea, Elisa

    2016-07-01

    The encapsulation of the photoactive, nontoxic, water-soluble, and air-stable cationic CORM [Mn(tacn)(CO)3]Br (tacn = 1,4,7-triazacyclononane) in different inorganic porous matrixes, namely, the metalorganic framework bio-MOF-1, (NH2(CH3)2)2[Zn8(adeninate)4(BPDC)6]·8DMF·11H2O (BPDC = 4,4'-biphenyldicarboxylate), and the functionalized mesoporous silicas MCM-41-SO3H and SBA-15-SO3H, is achieved by a cation exchange strategy. The CO release from these loaded materials, under simulated physiological conditions, is triggered by visible light. The results show that the silica matrixes, which are unaltered under physiological conditions, slow the kinetics of CO release, allowing a more controlled CO supply. In contrast, bio-MOF-1 instability leads to the complete leaching of the CORM. Nevertheless, the degradation of the MOF matrix gives rise to an enhanced CO release rate, which is related to the presence of free adenine in the solution. PMID:27291890

  4. Adsorptive removal of methyl orange from aqueous solution with metal-organic frameworks, porous chromium-benzenedicarboxylates

    International Nuclear Information System (INIS)

    Two typical highly porous metal-organic framework (MOF) materials based on chromium-benzenedicarboxylates (Cr-BDC) obtained from Material of Institute Lavoisier with special structure of MIL-101 and MIL-53 have been used for the adsorptive removal of methyl orange (MO), a harmful anionic dye, from aqueous solutions. The adsorption capacity and adsorption kinetic constant of MIL-101 are greater than those of MIL-53, showing the importance of porosity and pore size for the adsorption. The performance of MIL-101 improves with modification: the adsorption capacity and kinetic constant are in the order of MIL-101 < ethylenediamine-grafted MIL-101 < protonated ethylenediamine-grafted MIL-101 (even though the porosity and pore size are slightly decreased with grafting and further protonation). The adsorption capacity of protonated ethylenediamine-grafted MIL-101 decreases with increasing the pH of an aqueous MO solution. These results suggest that the adsorption of MO on the MOF is at least partly due to the electrostatic interaction between anionic MO and a cationic adsorbent. Adsorption of MO at various temperatures shows that the adsorption is a spontaneous and endothermic process and that the entropy increases (the driving force of the adsorption) with MO adsorption. The adsorbent MIL-101s are re-usable after sonification in water. Based on this study, MOFs can be suggested as potential re-usable adsorbents to remove anionic dyes because of their high porosity, facile modification and ready re-activation.

  5. Tunable rare-earth fcu-MOFs: A platform for systematic enhancement of CO2 adsorption energetics and uptake

    KAUST Repository

    Xue, Dongxu

    2013-05-22

    A series of fcu-MOFs based on rare-earth (RE) metals and linear fluorinated/nonfluorinated, homo/heterofunctional ligands were targeted and synthesized. This particular fcu-MOF platform was selected because of its unique structural characteristics combined with the ability/potential to dictate and regulate its chemical properties (e.g., tuning of the electron-rich RE metal ions and high localized charge density, a property arising from the proximal positioning of polarizing tetrazolate moieties and fluoro-groups that decorate the exposed inner surfaces of the confined conical cavities). These features permitted a systematic gas sorption study to evaluate/elucidate the effects of distinctive parameters on CO2-MOF sorption energetics. Our study supports the importance of the synergistic effect of exposed open metal sites and proximal highly localized charge density toward materials with enhanced CO2 sorption energetics. © 2013 American Chemical Society.

  6. Spectroscopic characterization of van der Waals interactions in a metal organic framework with unsaturated metal centers: MOF-74-Mg

    International Nuclear Information System (INIS)

    The adsorption energies of small molecules in nanoporous materials are often determined by isotherm measurements. The nature of the interaction and the response of the host material, however, can best be studied by spectroscopic methods. We show here that infrared absorption and Raman spectroscopy measurements together with density functional theory calculations, utilizing the novel van der Waals density functional vdW-DF, constitute a powerful approach to studying the weak van der Waals interactions associated with the incorporation of small molecules in these materials. In particular, we show how vdW-DF assists the interpretation of the vibrational spectroscopy data to uncover the binding sites and energies of these molecules, including the subtle dependence on loading of the IR asymmetric stretch mode of CO2 when adsorbed in MOF-74-Mg. To gain a better understanding of the adsorption mechanism of CO2 in MOF-74-Mg, the results are compared with CO within MOF-74-Mg.

  7. UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation.

    Science.gov (United States)

    Luo, Feng; Yan, Changsheng; Dang, Lilong; Krishna, Rajamani; Zhou, Wei; Wu, Hui; Dong, Xinglong; Han, Yu; Hu, Tong-Liang; O'Keeffe, Michael; Wang, Lingling; Luo, Mingbiao; Lin, Rui-Biao; Chen, Banglin

    2016-05-01

    A new metal-organic framework Zn2(H2O)(dobdc)·0.5(H2O) (UTSA-74, H4dobdc = 2,5-dioxido-1,4-benzenedicarboxylic acid), Zn-MOF-74/CPO-27-Zn isomer, has been synthesized and structurally characterized. It has a novel four coordinated fgl topology with one-dimensional channels of about 8.0 Å. Unlike metal sites in the well-established MOF-74 with a rod-packing structure in which each of them is in a five coordinate square pyramidal coordination geometry, there are two different Zn(2+) sites within the binuclear secondary building units in UTSA-74 in which one of them (Zn1) is in a tetrahedral while another (Zn2) in an octahedral coordination geometry. After activation, the two axial water molecules on Zn2 sites can be removed, generating UTSA-74a with two accessible gas binding sites per Zn2 ion. Accordingly, UTSA-74a takes up a moderately high and comparable amount of acetylene (145 cm(3)/cm(3)) to Zn-MOF-74. Interestingly, the accessible Zn(2+) sites in UTSA-74a are bridged by carbon dioxide molecules instead of being terminally bound in Zn-MOF-74, so UTSA-74a adsorbs a much smaller amount of carbon dioxide (90 cm(3)/cm(3)) than Zn-MOF-74 (146 cm(3)/cm(3)) at room temperature and 1 bar, leading to a superior MOF material for highly selective C2H2/CO2 separation. X-ray crystal structures, gas sorption isotherms, molecular modeling, and simulated and experimental breakthroughs comprehensively support this result. PMID:27113684

  8. Effect of pendant isophthalic acid moieties on the adsorption properties of light hydrocarbons in HKUST-1-like tbo -MOFs: Application to methane purification and storage

    KAUST Repository

    Belmabkhout, Youssef

    2014-01-01

    Equilibrium adsorption of methane (CH4), C2+ gases (ethane (C2H6), ethylene (C2H4), propane (C3H8), and propylene (C3H6)), and carbon dioxide (CO2) was measured on a series of tbo-MOFs (topological analogues of the prototypical MOF, HKUST-1, correspondingly dubbed tbo-MOF-1), which were developed via the supermolecular building layer (SBL) pillaring strategy. Specifically, tbo-MOF-2 and its isoreticular, functionalized analogue, tbo-MOF-2-{CH2O[Ph(CO2H)2]}2 (or tbo-MOF-3), which is characterized by pendant isophthalic acid moieties freely pointing into the cavities, were evaluated on the basis of potential use in methane storage and C2+/CH4 separation. The parent, tbo-MOF-2, showed high gravimetric and volumetric CH4 uptake, close to the U.S. Department of Energy (DOE) target for methane storage at 35 bar and room temperature. Though the presence of the pendant isophthalic acid moiety in the analogous compound, tbo-MOF-3, led to a decrease in total CH4 uptake, due mainly to the reduced size of the cavities, interestingly, it increased the affinity of the SBL-based tbo-MOF platform for propane, propene, ethane, and ethylene at low pressures compared with CH4, due additionally to the enhanced interactions of the highly polarizable light hydrocarbons with the isophthalic acid moiety. Using Ideal Adsorption Solution Theory (IAST), the predicted mixture adsorption equilibria for the C3H8/CH4, C3H6/CH4, C2H6/CH4, C2H4/CH4, and C3H8/CO2 systems showed high adsorption selectivity for C2+ over methane for tbo-MOF-3 compared with tbo-MOF-2. The high working storage capacity of tbo-MOF-2 and the high affinity of tbo-MOF-3 for C2+ over CH4 and CO2 make tbo-MOF an ideal platform for studies in gas storage and separation.

  9. Simulations of hydrogen sorption in rht-MOF-1: identifying the binding sites through explicit polarization and quantum rotation calculations

    KAUST Repository

    Pham, Tony

    2014-01-01

    Grand canonical Monte Carlo (GCMC) simulations of hydrogen sorption were performed in rht-MOF-1, a metal-organic framework (MOF) that consists of isophthalate groups joined by copper paddlewheel clusters and Cu3O trimers through tetrazolate moeities. This is a charged rht-MOF that contains extra-framework nitrate counterions within the material. For the simulations performed herein, excellent agreement with experiment was achieved for the simulated hydrogen sorption isotherms and calculated isosteric heat of adsorption, Qst, values only when using a polarizable potential. Thermodynamic agreement is demonstrated via comparing to experimental isotherms and binding sites are revealed by combining simulation and inelastic neutron scattering (INS) data. Simulations involving explicit many-body polarization interactions assisted in the determination of the binding sites in rht-MOF-1 through the distribution of the induced dipoles that led to strong adsorbate interactions. Four distinct hydrogen sorption sites were determined from the polarization distribution: the nitrate ions located in the corners of the truncated tetrahedral cages, the Cu2+ ions of the paddlewheels that project into the truncated tetrahedral and truncated octahedral cages (Cu1 ions), the Cu2+ ions of the Cu3O trimers (Cu3 ions), and the sides of the paddlewheels in the cuboctahedral cage. The simulations revealed that the initial sorption sites for hydrogen in rht-MOF-1 are the nitrate ions; this site corresponds to the high initial Qst value for hydrogen (9.5 kJ mol-1) in the MOF. The radial distribution functions, g(r), about the Cu2+ ions at various loadings revealed that the Cu1 ions are the preferred open-metal sorption sites for hydrogen at low loading, while the Cu3 ions become occupied at higher loadings. The validation of the aforementioned sorption sites in rht-MOF-1 was confirmed by calculating the two-dimensional quantum rotational levels about each site and comparing the levels to the

  10. Metal filled porous carbon

    Science.gov (United States)

    Gross, Adam F.; Vajo, John J.; Cumberland, Robert W.; Liu, Ping; Salguero, Tina T.

    2011-03-22

    A porous carbon scaffold with a surface and pores, the porous carbon scaffold containing a primary metal and a secondary metal, where the primary metal is a metal that does not wet the surface of the pores of the carbon scaffold but wets the surface of the secondary metal, and the secondary metal is interspersed between the surface of the pores of the carbon scaffold and the primary metal.

  11. Combustion within Porous Waste

    OpenAIRE

    Pfahl, Ulrich; Shepherd, Joseph E.; Unal, Cetin

    1998-01-01

    Flammable gases (primarily hydrogen and nitrous oxide but also ammonia and methane) are continuously being generated within the waste contained in the tank farms at Hanford Site. Some portions of the waste are porous and conceivably, a combustion event could occur within the waste due to accidental ignition. This has been postulated as a potential hazard since deflagrations and detonations are observed in laboratory experiments to propagate through combustible gases in porous materials, or ...

  12. Porphyrin-Alkaline Earth MOFs with the Highest Adsorption Capacity for Methylene Blue.

    Science.gov (United States)

    Hou, Yuxia; Sun, Junshan; Zhang, Daopeng; Qi, Dongdong; Jiang, Jianzhuang

    2016-04-25

    A series of four porphyrin-alkaline earth metal- organic frameworks [Mg(HDCPP)2 (DMF)2 ]n ⋅(H2 O)7 n (1), [Ca(HDCPP)2 (H2 O)2 ]n (DMF)1.5 n (2), [Sr(DCPP)(H2 O)(DMA)]n (3), and [Ba(DCPP)(H2 O)(DMA)]n (4) was isolated for the first time from solvothermal reaction between metal-free 5,15-di(4- carboxyphenyl)porphyrin (H2 DCPP) and alkaline earth ions. Single-crystal X-ray diffraction analysis reveals the 2D and 3D supramolecular network with periodic nanosized porosity for 1/2 and 3/4, respectively. The whole series of MOFs, in particular, compounds 1 and 2 with intrinsic low molecular formula weight, exhibit superior adsorption performance for methylene blue (MB) with excellent capture capacity as represented by the thus far highest adsorption amount of 952 mg g(-1) for 2 and good selectivity, opening a new way for the potential application of the main group metal-based MOFs. PMID:27002679

  13. A single-ligand ultra-microporous MOF for precombustion CO2 capture and hydrogen purification

    Science.gov (United States)

    Nandi, Shyamapada; De Luna, Phil; Daff, Thomas D.; Rother, Jens; Liu, Ming; Buchanan, William; Hawari, Ayman I.; Woo, Tom K.; Vaidhyanathan, Ramanathan

    2015-01-01

    Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate)2 with a cubic framework that exhibits exceptionally high CO2/H2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO2 adsorption-desorption cycling and has CO2 self-diffusivities of ~3 × 10−9 m2/s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO2-CO2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams. PMID:26824055

  14. Space group of the trirutile type structure of Li2MoF6

    International Nuclear Information System (INIS)

    Dilithium molybdenum hexafluoride, Li2MoF6, tetragonal, Mr = 223.83, a 4.6863 (7), c = 9.191 (2) A, V = 201.8 (2) A3, Dx = 3.683 Mg m-3, λ(Mo Kα) = 0.71069 A, F(000) = 206, single crystal refinement to R = 0.057 in space group P42/m21/n2/m based on 371 structure factors measured on a diffractometer by Brunton [(1971). Mater. Res. Bull. 6, 555] who preferred in his refinement of the same data space group P42212. Refinements in space groups P42, P42212 and P42/m21/n2/m show that Li2MoF6 crystallizes in the most highly symmetric of these space groups and is, therefore, isostructural with the aristotypic trirutile type. The decision for space group P42/m21/n2/m is based on the shape and orientation of the displacement ellipsoid of the F(1) atom and on the extremely high R value of the reflections not obeying the extinction condition of the n glide in space group P42212. The importance of the weak reflections in deciding a centrosymmetric-non-centrosymmetric space-group ambiguity is emphasized. (orig.)

  15. A multi-material ReALE method with MOF interface reconstruction

    International Nuclear Information System (INIS)

    We present a comparison of a classical arbitrary Lagrangian-Eulerian (ALE) method with a new multi-material reconnection-based arbitrary-Lagrangian-Eulerian (Re-ALE) strategy devoted to the computation of multi-material compressible fluid flows using the Moment Of Fluid (MOF) interface reconstruction. In ReALE we replace the rezoning phase of classical ALE method by a rezone where we allow the connectivity between cells of the mesh to change where rezoned grid is a polygonal mesh. Nevertheless, the ability of pure Lagrangian method to deal with multi-material problem, where mesh is aligned with material interfaces, is lost. In this work we have implemented MOF interface reconstruction on polygonal mesh in ReALE framework. This leads to a formulation that recover the Lagrangian features of following material and material interface that we lose using standard ALE methods with fixed connectivity. Some numerical examples, are used to clearly illustrate the robustness and accuracy of the new method. (authors)

  16. Rational design and synthesis of Ni x Co 3−x O 4 nanoparticles derived from multivariate MOF-74 for supercapacitors

    KAUST Repository

    Chen, Siru

    2015-01-01

    © The Royal Society of Chemistry 2015. Mixed transition metal oxides have attracted much attention recently due to their potential application in energy and environmental sciences. The emergence of multivariate MOFs recently has attracted great research attention and provides an opportunity for multivariate mixed-metal oxides. In this work, five isostructural, single-phase MOF-74 structures with different divalent metals (MOF-74-Co, MOF-74-Ni, MOF-74-NiCo1, MOF-74-NiCo2 and MOF-74-NiCo4) were synthesised by varying the mole ratios of Ni/Co mixed-metal ions. After annealing at the appropriate temperature, Co3O4, NiO and three kinds of NixCo3-xO4 mixed-metal oxide nanoparticles with high surface area were easily obtained and the metal ratio was readily controlled, enabling us to systematically investigate the effect of different metal species amounts on the electrochemical properties of the mixed-metal oxide materials. When these metal oxides were used as electrode materials for supercapacitors, we found that the mixed-metal oxides NixCo3-xO4 obtained from bimetallic MOF-74-NiCo structures had obvious advantages compared with the monometallic oxides of MOF-74-Ni and MOF-74-Co. In particular, the NixCo3-xO4-1 with the Ni/Co metal ratio 1:1 exhibited the highest capacitance of 797 F g-1 and excellent cycling stability.

  17. Correlation between the Microstructure of Porous Materials and the Adsorption Properties of H2 and D2

    International Nuclear Information System (INIS)

    One of the most challenging tasks toward the full implementation of the hydrogen based economy is the reversible storage of hydrogen for portable applications. Three main approaches have been investigated to store the hydrogen, storage as a compressed gas or a liquid, or through a direct chemical bond between the hydrogen atom and the material. The alternative approach, the most recently investigated, is the storage of hydrogen at cryogenic conditions. Storage by physisorption within porous adsorbents has particular advantages of complete reversibility, the fast refueling time, the low heat evolution, and above all increased safety. The nature of interaction of hydrogen, deuterium, and gas mixtures with porous adsorbents was exploited by performing thermal desorption spectroscopy (TDS) measurements. This sensitive experimental technique gives qualitative information about the different adsorption sites, which show different desorption temperatures depending on the interaction energy. After an appropriate calibration the amount of gas desorbed may be quantified. To gain a more fundamental insight into the available adsorption sites multiple TDS spectra were recorded, corresponding to different surface coverages (in the pressure range of 1 to 700 mbar), and different heating regimes. Different kind of porous adsorbents, conventional carbon-based materials and novel Metal Organic Framework Materials (MOFs), were used to investigate the hydrogen/deuterium physisorption mechanism. For carbon materials an increase in the hydrogen interaction potential was observed for adsorbents with narrow pore size. The confined geometry, where hydrogen simultaneously interacts with all the surrounding adsorbent walls, strengthens the interaction potential with the adsorbate molecule, thus, maximizing the total van der Waals force on the adsorbate. Crystalline MOFs are a new class of porous materials assembled from discrete metal centers, which act as framework nodes, and organic

  18. Effect of Synthesis Methods Using Renewable PODFA on Structural Characteristics of Metal-Organic Framework (MOF-5)

    Science.gov (United States)

    Othman, S. Z.; Misran, H.; Affendy, W. A.; Mahadi, N. F.

    2016-03-01

    In this work, metal-organic framework (MOF-5) syntheses were successfully synthesized with three different methods namely i) modified direct-mixing method ii) microwave assisted method and iii) autoclave assisted method without using surfactants. Palm oil derived fatty alcohol (PODFA), dodecyl alcohol (C8) was used as renewable non-surfactant template. Four prominent peaks were observed in all three samples attributable to the reflection planes of (200), (220), (400) and (420) of a cubic structure at ca. 2θ = 6.9°, 9.6°, 13.7° and 15.2°. The morphology of MOF-5 produced using modified direct-mixing method was faceted structure with average size of ca. 1 µm. In addition, the morphology of MOF-5 produced using microwave assisted synthesis was cubic structure with average size of ca. 8.34 µm. However, the morphology of MOF-5 using autoclave assisted method was interpenetrated cubic with average size of ca. 22.65 µm.

  19. A SIM-MOF: three-dimensional organisation of single-ion magnets with anion-exchange capabilities.

    Science.gov (United States)

    Baldoví, José J; Coronado, Eugenio; Gaita-Ariño, Alejandro; Gamer, Christoph; Giménez-Marqués, Mónica; Mínguez Espallargas, Guillermo

    2014-08-18

    The formation of a metal-organic framework (MOF) with nodes that have single-molecule magnet (SMM) behaviour has been achieved by using mononuclear lanthanoid analogues, also known as single-ion magnets (SIMs), which enormously simplifies the challenging issue of making SMM-MOFs. Here we present a rational design of a family of MOFs, [Ln(bipyNO)4](TfO)3⋅x solvent (Ln=Tb (1); Dy (2); Ho (3); Er (4); TfO=triflate), in which the lanthanoid centres have an square-antiprismatic coordination environment suitable for SIM behaviour. Magnetic measurements confirm the existence of slow magnetic relaxation typical of SMMs, which has been rationalised by means of a radial effective charge model. In addition, we have explored the incorporation of bulky polyoxometalates (POMs) into the cavities of the SIM-MOF by anion exchange, finding that they do not interfere with the slow magnetic relaxation. This demonstrates the robustness of the frameworks and opens the possibility of incorporating non-innocent anions. PMID:24804629

  20. Foams in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Marsden, S.S.

    1986-07-01

    In 1978 a literature search on selective blocking of fluid flow in porous media was done by Professor S.S. Marsden and two of his graduate students, Tom Elson and Kern Huppy. This was presented as SUPRI Report No. TR-3 entitled ''Literature Preview of the Selected Blockage of Fluids in Thermal Recovery Projects.'' Since then a lot of research on foam in porous media has been done on the SUPRI project and a great deal of new information has appeared in the literature. Therefore we believed that a new, up-to-date search should be done on foam alone, one which would be helpful to our students and perhaps of interest to others. This is a chronological survey showing the development of foam flow, blockage and use in porous media, starting with laboratory studies and eventually getting into field tests and demonstrations. It is arbitrarily divided into five-year time periods. 81 refs.

  1. Transport in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Dickenson, Eric [Univ. of California, Davis, CA (United States)

    1996-05-01

    A novel non-intrusive fluorescence imaging technique is used to study microscopic transport within porous media. The system consists of a column packed with heterogeneous-transparent particles and a refractive index-matched aqueous fluid seeded with fluorescent tracer particles or an organic dye. The flow through the column is illuminated by a planar sheet of laser beam and details of flow and transport through the porous regions can be observed microscopically and qualitative and quantitative transport information can be obtained. Various geometric, flow, and concentration quantities can be determined over a three dimensional volume within the column. The quantities include local and volumetrically averaged porosities, velocity and concentration fields, microscopic and volumetrically averaged dispersive fluxes and the dispersion coefficient. The qualitative and quantitative results will provide a better understanding for modeling of transport in porous media.

  2. Reversible flexible structural changes in multidimensional MOFs by guest molecules (I2, NH3) and thermal stimulation

    International Nuclear Information System (INIS)

    Three metal–organic frameworks (MOFs), [Cu(INA)2], [Cu(INA)2I2] and [Cu(INA)2(H2O)2(NH3)2], were synthesized with 3D, 2D, and 0D structures, respectively. Reversible flexible structural changes of these MOFs were reported. Through high temperature (60–100 °C) stimulation of I2 or ambient temperature stimulation of NH3, [Cu(INA)2] (3D) converted to [Cu(INA)2I2] (2D) and [Cu(INA)2(H2O)2(NH3)2] (0D); as the temperature increased to 150 °C, the MOFs changed back to their original form. In this way, this 3D MOF has potential application in the capture of I2 and NH3 from polluted water and air. XRD, TGA, SEM, NH3-TPD, and the measurement of gas adsorption were used to describe the changes in processes regarding the structure, morphology, and properties. - Graphical abstract: Through I2, NH3 molecules and thermal stimulation, the three MOFs can achieve reversible flexible structural changes. Different methods were used to prove the flexible reversible changes. - Highlights: • [Cu(INA)2] can flexible transform to [Cu(INA)2I2] and [Cu(INA)2(H2O)2(NH3)2] by adsorbing I2 or NH3. • The reversible flexible transformation related to material source, temperature and concentration. • Potential applications for the capture of I2 and NH3 from polluted water or air

  3. Encapsulated discrete octameric water cluster, 1D water tape, and 3D water aggregate network in diverse MOFs based on bisimidazolium ligands

    Science.gov (United States)

    Shi, Ruo-Bing; Pi, Min; Jiang, Shuang-Shuang; Wang, Yuan-Yuan; Jin, Chuan-Ming

    2014-08-01

    Four new metal-organic frameworks, [Zn(2-mBIM)2(SO3CF3)2·(H2O)4] (1), [Zn(BMIE)(1,4-BDC)]·(H2O)3 (2), [Cd(BIM)2(OH)(H2O)2(PF6)]·(H2O)4 (3), and [Cd(PA-BIM)2 (ClO4)2]·11.33H2O (4) (2-mBIM = bis(2-methylimidazol-1-yl)methane, BMIE = 1,2-bis[1-(2-methylimidazole)-diethoxy]ethane, BIM = bis(imidazol-1-yl)methane, and PA-BIM = 1,1-bis [(2-phenylazo)imidazol-1-yl]methane) have been prepared and structurally characterized. Complex 1 exhibits an infinite 1D cationic beaded-chain structure, which encapsulated discrete octameric water clusters that are comprised of a chair-like hexameric water cluster with two extra water molecules dangling on two diagonal vertices of the chair. Complex 2 forms a 1D infinite zigzag metal-organic chain structure with a 1D T4(0)A(4) water tape. Complexes 3 show a 2D grid-like sheet structure with the 1D water tape T4(0)A(0)2(0) motif. Complex 4 is a porous 3D MOF with tetrahedron-coordinated Cd(II) centers and trans-conformation PA-BIM ligands. These holes are occupied by a fascinating three-dimensional water clathrate network, which consists of cage-shaped structural tetradecameric water cluster (H2O)14 units and six independent bridged water molecules. The results suggest that the bisimidazolium ligands and anions play crucial roles in the formation of the different host structures and different guest water aggregations. Additionally, the thermal stabilities and photoluminescence spectra of the complexes have been discussed.

  4. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  5. Porous block nanofiber composite filters

    Energy Technology Data Exchange (ETDEWEB)

    Ginley, David S.; Curtis, Calvin J.; Miedaner, Alexander; Weiss, Alan J.; Paddock, Arnold

    2016-08-09

    Porous block nano-fiber composite (110), a filtration system (10) and methods of using the same are disclosed. An exemplary porous block nano-fiber composite (110) includes a porous block (100) having one or more pores (200). The porous block nano-fiber composite (110) also includes a plurality of inorganic nano-fibers (211) formed within at least one of the pores (200).

  6. Ambient pressure synthesis of MIL-100(Fe) MOF from homogeneous solution using a redox pathway.

    Science.gov (United States)

    Jeremias, Felix; Henninger, Stefan K; Janiak, Christoph

    2016-05-17

    Micro- to mesoporous iron(iii) trimesate MIL-100(Fe) is a MOF of high interest for numerous applications. With regard to large-scale synthesis, e.g., by continuous flow or the in situ deposition of coatings, a replacement for the conventional, hydrothermal low-yield fluoride-containing synthesis is desirable. In this contribution, we present a method to synthesize crystalline fluoride-free MIL-100(Fe) from iron(iii) nitrate and trimesic acid in zeotropic DMSO/water solution at normal ambient pressure involving a DMSO-nitrate redox pathway. Yields of 72%, surface areas of SBET = 1791 m(2) g(-1) and pore volumes of Vpore = 0.82 cm(3) g(-1) were achieved. PMID:27143562

  7. Polydimethylsiloxane Coating for a Palladium/MOF Composite: Highly Improved Catalytic Performance by Surface Hydrophobization.

    Science.gov (United States)

    Huang, Gang; Yang, Qihao; Xu, Qiang; Yu, Shu-Hong; Jiang, Hai-Long

    2016-06-20

    Surface wettability of active sites plays a crucial role in the activity and selectivity of catalysts. This report describes modification of surface hydrophobicity of Pd/UiO-66, a composite comprising a metal-organic framework (MOF) and stabilized palladium nanoparticles (NPs), using a simple polydimethylsiloxane (PDMS) coating. The modified catalyst demonstrated significantly improved catalytic efficiency. The approach can be extended to various Pd nanoparticulate catalysts for enhanced activity in reactions involving hydrophobic reactants, as the hydrophobic surface facilitates the enrichment of hydrophobic substrates around the catalytic site. PDMS encapsulation of Pd NPs prevents aggregation of NPs and thus results in superior catalytic recyclability. Additionally, PDMS coating is applicable to a diverse range of catalysts, endowing them with additional selectivity in sieving reactants with different wettability. PMID:27144320

  8. Orientational ortho-H 2 pair interactions in the microporous framework MOF-5

    Science.gov (United States)

    FitzGerald, Stephen A.; Eckdahl, Christopher T.; McDonald, Cooper S.; Nelson, Jocienne N.; Shinbrough, Kai; Lai, Holden W. H.; Rowsell, Jesse L. C.

    2015-10-01

    Infrared spectroscopy is used to observe the orientational fine structure arising from ortho-H2 adsorbed at the primary site of the microporous framework MOF-5. The Q1(1 ) vibrational transition shows at least two symmetrically spaced fine structure bands on either side of the main band. These grow in relative intensity with increasing H2 concentration indicative of interacting H2 pairs. This interpretation is strongly supported by D2 addition experiments, which cause a large increase in intensity of the fine structure bands with only minimal change in the main band. The spectra are analyzed in terms of H2-H2 electric quadrupole-quadrupole interactions. Consistent with this approach we observe no fine structure bands for the Q1(0 ) vibrational transition arising from para-H2, which does not possess a quadrupole moment.

  9. Ion exchange induced removal of Pb(ii) by MOF-derived magnetic inorganic sorbents

    Science.gov (United States)

    Chen, Dezhi; Shen, Weisong; Wu, Shaolin; Chen, Caiqin; Luo, Xubiao; Guo, Lin

    2016-03-01

    Nanoporous adsorbents of ZnO/ZnFe2O4/C were synthesized by using a metal organic framework (FeIII-modified MOF-5) as both the precursor and the self-sacrificing template. The adsorption properties of ZnO/ZnFe2O4/C toward Pb(ii) ions were investigated, including the pH effect, adsorption equilibrium and adsorption kinetics. The adsorption isotherms and kinetics were well described by using the Langmuir isotherm model and pseudo-second-order model, respectively. The MOF-derived inorganic adsorbents exhibited high absorption performance with a maximum adsorption capacity of 344.83 mg g-1. X-ray powder diffraction and high-resolution X-ray photoelectron spectroscopy suggest that Zn(ii) was substituted by a significant portion of Pb(ii) on the surface of ZnO nanocrystals. Microscopic observations also demonstrate the effect of Pb(ii) ions on ZnO crystals as reflected by the considerably reduced average particle size and defective outer layer. Quantitative measurement of the released Zn(ii) ions and the adsorbed Pb(ii) ions indicated a nearly linear relationship (R2 = 0.977). Moreover, Pb-containing ZnO/ZnFe2O4/C adsorbents are strongly magnetic allowing their separation from the water environment by an external magnet.Nanoporous adsorbents of ZnO/ZnFe2O4/C were synthesized by using a metal organic framework (FeIII-modified MOF-5) as both the precursor and the self-sacrificing template. The adsorption properties of ZnO/ZnFe2O4/C toward Pb(ii) ions were investigated, including the pH effect, adsorption equilibrium and adsorption kinetics. The adsorption isotherms and kinetics were well described by using the Langmuir isotherm model and pseudo-second-order model, respectively. The MOF-derived inorganic adsorbents exhibited high absorption performance with a maximum adsorption capacity of 344.83 mg g-1. X-ray powder diffraction and high-resolution X-ray photoelectron spectroscopy suggest that Zn(ii) was substituted by a significant portion of Pb(ii) on the surface of Zn

  10. MOF-Derived Tungstated Zirconia as Strong Solid Acids toward High Catalytic Performance for Acetalization.

    Science.gov (United States)

    Wang, Peng; Feng, Jian; Zhao, Yupei; Wang, Shaobin; Liu, Jian

    2016-09-14

    A strong solid acid, tungstated zirconia (WZ), has been prepared first using tungstate immobilized UiO-66 as precursors through a "double-solvent" impregnation method under mild calcination temperature. With moderate W contents, the as-synthesized WZ catalysts possess a high density of acid sites, and the proper heat treatment also has facilely led to a bunch of oligomeric tungsten clusters on stabilized tetragonal ZrO2. The resultant solid acids show an improved catalytic performance toward the benzaldehyde's acetalization in comparison with traditional zirconium hydroxide-prepared WZ. Notably, due to large surface area and additionally introduced strong acid sites, the MOF-derived WZ catalysts afforded conversion up to 86.0%. The facile method endows the WZ catalysts with superior catalytic activities and excellent recyclability, thus opening a new avenue for preparation of metal oxide-based solid superacids and superbases. PMID:27557351

  11. Metal Hydrides, MOFs, and Carbon Composites as Space Radiation Shielding Mitigators

    Science.gov (United States)

    Atwell, William; Rojdev, Kristina; Liang, Daniel; Hill, Matthew

    2014-01-01

    Recently, metal hydrides and MOFs (Metal-Organic Framework/microporous organic polymer composites - for their hydrogen and methane storage capabilities) have been studied with applications in fuel cell technology. We have investigated a dual-use of these materials and carbon composites (CNT-HDPE) to include space radiation shielding mitigation. In this paper we present the results of a detailed study where we have analyzed 64 materials. We used the Band fit spectra for the combined 19-24 October 1989 solar proton events as the input source term radiation environment. These computational analyses were performed with the NASA high energy particle transport/dose code HZETRN. Through this analysis we have identified several of the materials that have excellent radiation shielding properties and the details of this analysis will be discussed further in the paper.

  12. A homochiral vanadium-salen based cadmium bpdc MOF with permanent porosity as an asymmetric catalyst in solvent-free cyanosilylation.

    Science.gov (United States)

    Bhunia, Asamanjoy; Dey, Subarna; Moreno, José María; Diaz, Urbano; Concepcion, Patricia; Van Hecke, Kristof; Janiak, Christoph; Van Der Voort, Pascal

    2016-01-25

    A homochiral vanadium-salen based MOF with the pcu topology is constructed via in situ synthesis under solvothermal conditions. The synthesized MOF exhibits BET surface areas of 574 m(2) g(-1), showing the highest H2 adsorption capacity (1.05 wt% at 77 K, 1 bar) and the highest CO2 uptake (51 cm(3) g(-1) at 273 K, 1 bar) for currently known salen-based MOFs. This framework shows excellent performance as an asymmetric catalyst in solvent-free cyanosilylation. PMID:26621199

  13. POROUS DIKE INTAKE EVALUATION

    Science.gov (United States)

    The report gives results of an evaluation of a porous dike intake. A small-scale test facility was constructed and continuously operated for 2 years under field conditions. Two stone dikes of gabion construction were tested: one consisted of 7.5 cm stones; and the other, 20 cm st...

  14. Hydrophobic, Porous Battery Boxes

    Science.gov (United States)

    Bragg, Bobby J.; Casey, John E., Jr.

    1995-01-01

    Boxes made of porous, hydrophobic polymers developed to contain aqueous potassium hydroxide electrolyte solutions of zinc/air batteries while allowing air to diffuse in as needed for operation. Used on other types of batteries for in-cabin use in which electrolytes aqueous and from which gases generated during operation must be vented without allowing electrolytes to leak out.

  15. Porous polyethylene and proplast

    OpenAIRE

    Berghaus, Alexander; Mulch, G.; Handrock, M

    1984-01-01

    A comparative animal study showed that, after implantation in skull defects in guinea pigs, porous high-density polyethylene (PHDPE) was substantially better anchored in the bone than Proplast, and had greater stability of form and structure. In Proplast, ingrowth of fibrous tissue caused partial structural dilatation and fragmentation, which could limit its suitability for use in reconstructive surgery.

  16. One-pot assembly of metal/organic-acid sites on amine-functionalized ligands of MOFs for photocatalytic hydrogen peroxide splitting.

    Science.gov (United States)

    Qin, Lei; Li, Zhaowen; Hu, Qiong; Xu, Zehai; Guo, Xinwen; Zhang, Guoliang

    2016-06-01

    A one-pot organic-acid-directed post-synthetic modification allows molecular iron/citric acid complexes to be anchored into amine-functionalized MOFs by a simple and rapid liquid spraying method. Amidation between organic acid and -NH2 groups of ligands can lead to more small nanoparticles (NPs) that are well-dispersed into MOFs and exhibit high activity for photocatalytic H2O2 splitting. PMID:27166081

  17. Successful implementation of the stepwise layer-by-layer growth of MOF thin films on confined surfaces: Mesoporous silica foam as a first case study

    KAUST Repository

    Shekhah, Osama

    2012-01-01

    Here we report the successful growth of highly crystalline homogeneous MOF thin films of HKUST-1 and ZIF-8 on mesoporous silica foam, by employing a layer-by-layer (LBL) method. The ability to control and direct the growth of MOF thin films on confined surfaces, using the stepwise LBL method, paves the way for new prospective applications of such hybrid systems. © 2012 The Royal Society of Chemistry.

  18. Insights into the electrochemical behaviour of composite materials: Monovacant polyoxometalates - porous metal-organic framework

    International Nuclear Information System (INIS)

    The first electrochemical investigation of composites materials based in polyoxometalates (POMs) encapsulated in the porous Metal-Organic Framework (MOF) MIL-101 is reported. The electrochemical behaviour of the porous MIL-101 and composite materials based in two monovacant Keggin-type POMs {K7[PW11O39]·10H2O (PW11) and K8[SiW11O39]·13H2O (SiW11)} encapsulated in MIL-101 (respectively, PW11-MIL-101 and SiW11-MIL-101) were studied by cyclic voltammetry. Initially, to investigate the influence of the support MIL-101 in the electrochemical behaviour of the two monovacant POMs, the compounds were individually immobilized on the surface of a pyrolytic graphite (PG) electrode. A reversible surface-controlled redox signal attributed to the chromium metal centres (Cr3+/Cr2+) was identified in MIL-101, and this represents the first electrochemical study of this MOF material. The monovacant compounds PW11 and SiW11 also revealed surface-controlled processes corresponding to WVI ↔ WV reductions. PW11 showed two reversible signals (involving one or two electrons), whereas SiW11 showed a quasi-reversible one-electron and a reversible two-electron process for the first and second W reductions, respectively. For the latter, an extra process was detected and attributed to the formation of β-isomer (β-SiW11). When the composites materials PW11-MIL-101 and SiW11-MIL-101 were immobilized on the surface of the electrode, the support MIL-101 maintained its characteristic electrochemistry and the redox potentials of the POMs were not significantly changed. However, when encapsulated inside the cages of the support material the POMs revealed a distinct electrochemical behaviour, given that their redox processes became diffusion-controlled, indicating that the POMs have some degree of mobility inside the support framework.

  19. Selective and Efficient Removal of Mercury from Aqueous Media with the Highly Flexible Arms of a BioMOF.

    Science.gov (United States)

    Mon, Marta; Lloret, Francesc; Ferrando-Soria, Jesús; Martí-Gastaldo, Carlos; Armentano, Donatella; Pardo, Emilio

    2016-09-01

    A robust and water-stable metal-organic framework (MOF), featuring hexagonal channels decorated with methionine residues (1), selectively captures toxic species such as CH3 Hg(+) and Hg(2+) from water. 1 exhibits the largest Hg(2+) uptake capacity ever reported for a MOF, decreasing the [Hg(2+) ] and [CH3 Hg(+) ] concentrations in potable water from highly hazardous 10 ppm to the much safer values of 6 and 27 ppb, respectively. Just like with biological systems, the high-performance metal capture also involves a molecular recognition process. Both CH3 Hg(+) and Hg(2+) are efficiently immobilized by specific conformations adopted by the flexible thioether "claws" decorating the pores of 1. This leads to very stable structural conformations reminiscent of those responsible for the biological activity of the enzyme mercury reductase (MR). PMID:27529544

  20. Synthesis and integration of Fe-soc-MOF cubes into colloidosomes via a single-step emulsion-based approach

    KAUST Repository

    Pang, Maolin

    2013-07-17

    Bottom-up fabrication of complex 3D hollow superstructures from nonspherical building blocks (BBs) poses a significant challenge for scientists in materials chemistry and physics. Spherical colloidal silica or polystyrene particles are therefore often integrated as BBs for the preparation of an emerging class of materials, namely colloidosomes (using colloidal particles for Pickering stabilization and fusing them to form a permeable shell). Herein, we describe for the first time a one-step emulsion-based technique that permits the assembly of metal-organic framework (MOF) faceted polyhedral BBs (i.e., cubes instead of spheres) into 3D hollow superstructures (or "colloidosomes" ). The shell of each resultant hollow MOF colloidosome is constructed from a monolayer of cubic BBs, whose dimensions can be precisely controlled by varying the amount of emulsifier used in the synthesis. © 2013 American Chemical Society.

  1. Vibrational relaxation of hexafluoride compounds: MoF6, ReF6, SeF6, and WF6

    International Nuclear Information System (INIS)

    Ultrasonic attenuation has been measured in MoF6, ReF6, SeF6, and WF6 at 293 K. In all cases, a single relaxation process was observed and attributed to the total vibrational energy of the relaxing molecule. Isothermal relaxation times were found to be 2.8 x 10-8, 8.8 x 10-9, 2.9 x 10-7, and 2.3 x 10-8 s atm for MoF6, ReF6, SeF6, and WF6, respectively. Assuming series relaxation, those relaxation times can be converted to the number of collisions required for relaxation Z/sub vib/. The values of Z/sub vib/ vary with the energy of the lowest vibrational mode as expected from the simple Lambert--Salter correlation

  2. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance.

    Science.gov (United States)

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B Peter; Motkuri, Radha Kishan

    2016-01-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method. PMID:27306598

  3. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    Science.gov (United States)

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B. Peter; Motkuri, Radha Kishan

    2016-06-01

    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  4. A supermolecular building layer approach for gas separation and storage applications: the eea and rtl MOF platforms for CO 2 capture and hydrocarbon separation

    KAUST Repository

    Chen, Zhijie

    2015-02-11

    The supermolecular building layer (SBL) approach was employed to deliberately synthesize five novel metal–organic frameworks (1–5) with an exposed array of amide or amine functionalities within their pore system. The ability to decorate the pores with nitrogen donor moieties offers potential to evaluate/elucidate the structure–adsorption property relationship. Two MOF platforms, eea-MOF and rtl-MOF, based on pillaring of kgm-a or sql-a layers with heterofunctional 3-connected organic building blocks were targeted and constructed to purposely introduce and expose the desired amide or amine functionalities. Interestingly, gas adsorption properties of eea-MOF-4 (1) and eea-MOF-5 (2) showed that by simply altering the nitrogen donor position within the ligand, it is possible to relatively reduce the pore size of the related eea-MOF material and subsequently increase the associated CO2 uptake. The slightly confined pore space in 2, relative to 1, has enabled an enhancement of the pore local charge density and thus the observed relative increase in the CO2 and H2 isosteric heat of adsorption (Qst). In addition, light hydrocarbon adsorption studies revealed that 2 is more selective toward C2H6 and C3H8 over CH4 than 1, as exemplified for C2H6 : CH4 (5 : 95) or C3H8 : CH4 (5 : 95) binary gas mixtures.

  5. A supermolecular building layer approach for gas separation and storage applications: The eea and rtl MOF platforms for CO2 capture and hydrocarbon separation

    KAUST Repository

    Chen, Zhijie

    2015-01-01

    The supermolecular building layer (SBL) approach was employed to deliberately synthesize five novel metal-organic frameworks (1-5) with an exposed array of amide or amine functionalities within their pore system. The ability to decorate the pores with nitrogen donor moieties offers potential to evaluate/elucidate the structure-adsorption property relationship. Two MOF platforms, eea-MOF and rtl-MOF, based on pillaring of kgm-a or sql-a layers with heterofunctional 3-connected organic building blocks were targeted and constructed to purposely introduce and expose the desired amide or amine functionalities. Interestingly, gas adsorption properties of eea-MOF-4 (1) and eea-MOF-5 (2) showed that by simply altering the nitrogen donor position within the ligand, it is possible to relatively reduce the pore size of the related eea-MOF material and subsequently increase the associated CO2 uptake. The slightly confined pore space in 2, relative to 1, has enabled an enhancement of the pore local charge density and thus the observed relative increase in the CO2 and H2 isosteric heat of adsorption (Qst). In addition, light hydrocarbon adsorption studies revealed that 2 is more selective toward C2H6 and C3H8 over CH4 than 1, as exemplified for C2H6:CH4 (5:95) or C3H8:CH4 (5:95) binary gas mixtures. This journal is

  6. Strong, Lightweight, Porous Materials

    Science.gov (United States)

    Leventis, Nicholas; Meador, Mary Ann B.; Johnston, James C.; Fabrizio, Eve F.; Ilhan, Ulvi

    2007-01-01

    A new class of strong, lightweight, porous materials has been invented as an outgrowth of an effort to develop reinforced silica aerogels. The new material, called X-Aerogel is less hygroscopic, but no less porous and of similar density to the corresponding unmodified aerogels. However, the property that sets X-Aerogels apart is their mechanical strength, which can be as much as two and a half orders of magnitude stronger that the unmodified aerogels. X-Aerogels are envisioned to be useful for making extremely lightweight, thermally insulating, structural components, but they may also have applications as electrical insulators, components of laminates, catalyst supports, templates for electrode materials, fuel-cell components, and filter membranes.

  7. Convection in Porous Media

    CERN Document Server

    Nield, Donald A

    2013-01-01

    Convection in Porous Media, 4th Edition, provides a user-friendly introduction to the subject, covering a wide range of topics, such as fibrous insulation, geological strata, and catalytic reactors. The presentation is self-contained, requiring only routine mathematics and the basic elements of fluid mechanics and heat transfer. The book will be of use not only to researchers and practicing engineers as a review and reference, but also to graduate students and others entering the field. The new edition features approximately 1,750 new references and covers current research in nanofluids, cellular porous materials, strong heterogeneity, pulsating flow, and more. Recognized as the standard reference in the field Includes a comprehensive, 250-page reference list Cited over 2300 times to date in its various editions Serves as an introduction for those entering the field and as a comprehensive reference for experienced researchers Features new sections on nanofluids, carbon dioxide sequestration, and applications...

  8. On demand: The singular rht net, an ideal blueprint for the construction of a metal-organic framework (mof) platform

    KAUST Repository

    Eubank, Jarrod F.

    2012-09-07

    The exceptional nature of the rht-MOF platform, based on a singular edge-transitive net (the only net for the combination of 3- and 24-connected nodes), makes it an ideal target in crystal chemistry. The high level of control indicates an unparalleled blueprint for isoreticular functional materials (without concern for interpenetration) for targeted applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Post-Synthetic Shaping of Porosity and Crystal Structure of Ln-Bipy-MOFs by Thermal Treatment

    Directory of Open Access Journals (Sweden)

    Philipp R. Matthes

    2015-07-01

    Full Text Available The reaction of anhydrous lanthanide chlorides together with 4,4′-bipyridine yields the MOFs 2∞[Ln2Cl6(bipy3]·2bipy, with Ln = Pr − Yb, bipy = 4,4′-bipyridine, and 3∞[La2Cl6(bipy5]·4bipy. Post-synthetic thermal treatment in combination with different vacuum conditions was successfully used to shape the porosity of the MOFs. In addition to the MOFs microporosity, a tuneable mesoporosity can be implemented depending on the treatment conditions as a surface morphological modification. Furthermore, thermal treatment without vacuum results in several identifiable crystalline high-temperature phases. Instead of collapse of the frameworks upon heating, further aggregation under release of bipy is observed. 3∞[LaCl3(bipy] and 2∞[Ln3Cl9(bipy3], with Ln = La, Pr, Sm, and 1∞[Ho2Cl6(bipy2] were identified and characterized, which can also exhibit luminescence. Besides being released upon heating, the linker 4,4′-bipyridine can undergo activation of C-C bonding in ortho-position leading to the in-situ formation of 4,4′:2′,2′′:4′′,4′′′-quaterpyridine (qtpy. qtpy can thereby function as linker itself, as shown for the formation of the network 2∞[Gd2Cl6(qtpy2(bipy2]·bipy. Altogether, the manuscript elaborates the influence of thermal treatment beyond the usual activation procedures reported for MOFs.

  10. A new MOF-5 homologue for selective separation of methane from C2 hydrocarbons at room temperature

    Directory of Open Access Journals (Sweden)

    Yabing He

    2014-12-01

    Full Text Available A new MOF-5 homologue compound UTSA-10 has been obtained under solvothermal conditions from a mixture of Zn(NO32⋅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.

  11. 19F spin-lattice relaxation in WF6, MoF6, and UF6 gases

    International Nuclear Information System (INIS)

    Spin-lattice relaxation times have been measured for the fluorine nuclei in gaseous WF6, MoF6 and UF6 as a function of temperature in the dilute gas region. The measured temperature dependences are as predicted for relaxation resulting from a spin-rotation interaction. Effective cross sections for the transfer of angular momentum to molecular rotation during collisions are deduced. (author)

  12. Luminescence and Magnetic Properties of Two Three -Dimensional Terbium and Dysprosium MOFs Based on Azobenzene-4,4 '-Dicarboxylic Linker

    OpenAIRE

    Fernández, Belén; Oyarzabal Epelde, Itziar; Seco Botana, José Manuel; San Sebastián Larzabal, Eider; Fairen-Jiménez, David; Gómez-Ruiz, Santiago; Salinas-Castillo, Alfonso; Calahorro, Antonio J.; Rodríguez-Diéguez, Antonio

    2016-01-01

    We report the in situ formation of two novel metal-organic frameworks based on terbium and dysprosium ions using azobenzene-4,4-dicarboxylic acid (H(2)abd) as ligand, synthesized by soft hydrothermal routes. Both materials show isostructural three-dimensional networks with channels along a axis and display intense photoluminescence properties in the solid state at room temperature. Textural properties of the metal-organic frameworks (MOFs) have been fully characterized although no appreciable...

  13. The development of new materials such MOFs for CO2 capture and alkylation of aromatic compounds

    International Nuclear Information System (INIS)

    This thesis is a European project TOPCOMBI of 22 partners. More specifically, this work is the result of collaboration between ENI (Italy), ITQ (Spain), Repsol (Spain) and IRCELYON (France). This work consists of 2 different themes which improvements can be obtained by finding new materials tailored to the needs. The global energy demands are and will be constantly rising in the coming years. In order to meet this need, new resources must be found and further optimized. Fossil fuels are among the most used resources in the world. Among this 3, natural gas appears to be the most promising point of view of energy efficiency and ecological impact. However, many gas fields cannot be treated because there are too small or too contaminated to be economically viable. One way to make them attractive is to lower the cost of purification using novel separation techniques such as the PSA system. However, there is no currently effective adsorbent to allow a viable economic cleansing. Today, the alkylation reactions represent a very important economic interest. Industrial processes are typically carried out by homogeneous acid reactions or not. Seeing the new environmental restrictions, some homogeneous catalytic processes must be replaced by heterogeneous catalytic reactions with the same yields. To do this, new materials to acid characters were used: the zeolites. However the small size of pores of these compounds prevents selective alkylation reactions of molecules too large compounds such as poly-aromatic. For twenty years, new microporous crystalline compounds have emerged: the MOFs, Metal Organic Frameworks. These compounds have the characteristic to be obtained with different metal cations and organic ligands. These combinations give a wide variety of these compounds at the level of reactivity, pore volume and pore size. In this work, we tried to get different materials with specific characteristics in order to use them in methods for purification of methane in acid

  14. Electrochemically Formed Porous Silica

    Directory of Open Access Journals (Sweden)

    Jean-Noël Chazalviel

    2011-04-01

    Full Text Available Controlled electrochemical formation of porous silica can be realized in dilute aqueous, neutral-pH, fluoride medium. Formation of a porous film is initiated by sweeping the potential applied to silicon to values higher than 20 V. Film formation, reaching a steady state, may be pursued in a wide range of potentials, including lower potentials. The origin of a threshold potential for porous film initiation has been explained quantitatively. All of the films appear mesoporous. Films grown at high potentials exhibit a variety of macrostructures superimposed on the mesoporosity. These macrostructures result from selective dissolution of silica induced by local pH lowering due to oxygen evolution. Films grown at potentials lower than 15 V appear uniform on the micrometer scale. However, all of the films also exhibit a stratified structure on the scale of a few tens of nanometres. This periodic structure can be traced back to the oscillatory behavior observed during the electrochemical dissolution of silicon in fluoride medium. It suggests that periodic breaking of the growing film may be responsible for this morphology.

  15. N-GQDs and Eu(3+) co-encapsulated anionic MOFs: two-dimensional luminescent platform for decoding benzene homologues.

    Science.gov (United States)

    Weng, Han; Yan, Bing

    2016-06-01

    Highly luminescent hybrids N-GQDs/Eu(3+)@Mg-MOF (N-GQDs = N atom doped graphene quantum dots and Mg-MOF = {[Mg3(ndc)2.5(HCO2)2(H2O)][NH2Me2]·2H2O·DMF}) have been synthesized and their photophysical properties were investigated. The resulting luminescent material can exhibit dual-emission from N-GQDs and Eu(3+) when excited at 394 nm, whereas the emission of ligand-based and Eu(3+) can be collected when excited at 349 nm. Exposed to a series of atmospheric benzene homologues (BTEX) in a sealed environment for 1 hour at 25 °C, N-GQDs/Eu(3+)@Mg-MOF shows excellent fingerprint correlations between the exact BTEX and the emission peak height ratio of IL/IEu (luminescent intensity ratio of ligand-based emission at 414 nm and Eu(3+)-based emission at 618 nm) and IEu/IN-GQDs (luminescent intensity ratio of l-emission based on N-GQDs at 443 nm and Eu(3+)-based emission at 618 nm), which makes it possible for this material to become a good platform for the detection of BTEX. PMID:27145714

  16. Neutron diffraction and in situ gas-loading investigations of functional MOFs for energy-relevant gas separations

    International Nuclear Information System (INIS)

    Intense research is currently directed towards realising metal-organic frameworks (MOFs) for industrially-applied gas separation and storage due to their unique structural properties, including: robustness; thermal and chemical stability; unprecedented internal surface area; and high void volume. A particular focus of current research is the development of MOFs for the separation of CO, from the other components of flue gas in fossil-fuelled power plants. The use of NPD to study gas adsorption in framework materials is a relatively new but growing field. Structural measurements, which show the arrangement of both the host and guest, allow derivation of the nature of the host-guest interaction, and the host's response to the guest. The capability to perform these measurements, with accurate gas dosing and temperature control, has recently been realised at ANSTO's Bragg Institute. Using these techniques, we have investigated the adsorption mechanisms of a number of gases in selected new and established MOFs that display impressive selectivity for specific gases. The location and orientation of industrially-relevant gases including D2, 02, CO2, and CD4, within their crystal structures provide insights into the modes of binding, which will help to tune the materials' performance and benefit the design and development process for the next generation of materials.

  17. MOF-Based Membrane Encapsulated ZnO Nanowires for Enhanced Gas Sensor Selectivity.

    Science.gov (United States)

    Drobek, Martin; Kim, Jae-Hun; Bechelany, Mikhael; Vallicari, Cyril; Julbe, Anne; Kim, Sang Sub

    2016-04-01

    Gas sensors are of a great interest for applications including toxic or explosive gases detection in both in-house and industrial environments, air quality monitoring, medical diagnostics, or control of food/cosmetic properties. In the area of semiconductor metal oxides (SMOs)-based sensors, a lot of effort has been devoted to improve the sensing characteristics. In this work, we report on a general methodology for improving the selectivity of SMOx nanowires sensors, based on the coverage of ZnO nanowires with a thin ZIF-8 molecular sieve membrane. The optimized ZnO@ZIF-8-based nanocomposite sensor shows markedly selective response to H2 in comparison with the pristine ZnO nanowires sensor, while showing the negligible sensing response to C7H8 and C6H6. This original MOF-membrane encapsulation strategy applied to nanowires sensor architecture pave the way for other complex 3D architectures and various types of applications requiring either gas or ion selectivity, such as biosensors, photo(catalysts), and electrodes. PMID:27003470

  18. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, Inés; Díaz, Eva; Vega, Aurelio [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Ordóñez, Salvador, E-mail: sordonez@uniovi.es [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Guerrero-Ruiz, Antonio [Department of Inorganic and technical Chemistry, UNED, 28040 Madrid (Spain); Castillejos-López, Eva; Rodríguez-Ramos, Inmaculada [Instituto de Catálisis y Petroleoquímica, CSIC, Madrid (Spain)

    2015-02-20

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu{sub 3}(BTC){sub 2} and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • I{sup sp} is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu{sub 3}(BTC){sub 2} and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu{sub 3}(BTC){sub 2}, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores.

  19. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    International Nuclear Information System (INIS)

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu3(BTC)2 and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • Isp is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu3(BTC)2 and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu3(BTC)2, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores

  20. Synthesis of MOF templated Cu/CuO@TiO2 nanocomposites for synergistic hydrogen production.

    Science.gov (United States)

    Mondal, Indranil; Pal, Ujjwal

    2016-02-14

    A copper metal-organic framework (Cu-MOF) provides access to Cu/CuO@TiO2 hybrid nanocomposites with highly dispersive copper species adsorbed on a TiO2 semiconducting system. This novel nanostructure exhibits efficient hydrogen evolution performance under solar illumination of intensity ∼1 Sun. The rate of H2 production was systematically optimized under different operational parameters. Experimental observation reveals that mesoporous Cu/CuO@TiO2 nanocomposite with 0.5 wt% Cu loading showed the highest rate of H2 production (286 mmol g(-1) h(-1)), which is considerably higher than that of CuO loaded TiO2 prepared using a conventional impregnation method. This high photocatalytic H2 production activity is attributed predominantly to the presence of surface deposited Cu(0) species and the small size of the heterojunction (1-2 nm) between CuO and TiO2, which facilitate interfacial charge carrier transfer from the TiO2 nanoparticles. The catalyst showed good recyclability under prolonged exposure (30 h) to solar irradiation. Unlike many Pt decorated TiO2 photocatalysts, this hybrid photocatalyst provides an inexpensive means of harnessing solar energy. PMID:26806274

  1. Selective formation of porous silicon

    Science.gov (United States)

    Fathauer, Robert W. (Inventor); Jones, Eric W. (Inventor)

    1993-01-01

    A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H2O. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

  2. Coumarin-modified microporous-mesoporous Zn-MOF-74 showing ultra-high uptake capacity and photo-switched storage/release of U(VI) ions.

    Science.gov (United States)

    Zhang, Le; Wang, Lin Lin; Gong, Le Le; Feng, Xue Feng; Luo, Ming Biao; Luo, Feng

    2016-07-01

    Driven by an energy crisis but consequently puzzled by various environmental problems, uranium, as the basic material of nuclear energy, is now receiving extensive attentions. In contrast to numerous sorbents applied in this field, metal-organic framework (MOFs), as a renovated material platform, has only recently been developed. How to improve the adsorption capacity of MOF materials towards U(VI) ions, as well as taking advantage of the nature of these MOFs to design photo-switched behaviour for photo-triggered storage/release of U(VI) ions are at present urgent problems and great challenges to be solved. Herein, we show a simple and facile method to target the goal. Through coordination-based post-synthetic strategy, microporous- mesoporous Zn-MOF-74 was easily functionalized by grafting coumarin on coordinatively unsaturated Zn(II) centers, yielding a series of coumarin-modified Zn-MOF-74 materials. The obtained samples displayed ultra-high adsorption capacity for U(VI) ions from water at pH value of 4 with maximum adsorption capacities as high as 360mg/g (the record value in MOFs) and a remarkable photo-switched capability of 50mg/g at pH value of 4. To the best of knowledge, and in contrast to the well-known photo-switched behaviour towards CO2, dye (propidium iodide), as well as fluorescence observed in MOFs, this is the first study that shows a photo-switched behaviour towards radioactive U(VI) ions in aqueous solution. PMID:26954473

  3. Preparation and Characterization of a Hydrophobic Metal-Organic Framework Membrane Supported on Thin Porous Metal Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Canfield, Nathan L.; Liu, Wei

    2016-02-29

    A hydrophobic metal-organic framework (MOF) UiO-66-CH3 is prepared and its solvothermal stability is investigated in comparison to UiO-66. It is confirmed that the MOF stability is enhanced by introduction of the two methyl groups, while the water adsorption is reduced. Given its hydrophobicity and stability, UiO-66-CH3 is proposed as an attractive membrane material for gas separation under moisture conditions. The UiO-66-CH3 membrane is prepared on a 50µm-thin porous Ni support sheet for the first time by use of a secondary growth method. It is found that uniform seed coating on the support is necessary to form a continuous membrane. In addition to growth time and temperature, presence of a modulator in the growth solution is found to be useful for controlling hydrothermal membrane growth on the seeded support. A dense, inter-grown membrane layer is formed by 24-h growth over a temperature range from 120 oC to 160 oC. The membrane surface comprises 500 nm octahedral crystals, which are supposed to grow out of the original 100 nm spherical seeding crystals. The separation characteristics of resulting membranes are tested with pure CO2, air, CO2/air mixture, and humid CO2/air mixture. CO2 permeance as high as 1.9E-06 mol/m2/s/Pa at 31oC is obtained. Unlike the hydrophilic zeolite membranes, CO2 permeation through this membrane is not blocked by the presence of water vapor in the feed gas. The results suggest that this MOF framework is a promising membrane material worth to be further investigated for separation of CO2 and other small molecules from humid gas mixtures.

  4. Moisture Sorption in Porous Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2007-01-01

    Abstract: Information on pore geometry is very important in any study of the mechanical and physical behavior of porous materials. Unfortunately pores are not very accessible for direct measurements. Indirect methods have to be used which involve impregnation (sorption) experiments from which...... subject considered this software is available on request to the author. Keywords: Porous materials, moisture, adsorption, desorption, BET-parameters....

  5. Understanding Hydrogen Sorption in In- soc -MOF: A Charged Metal-Organic Framework with Open-Metal Sites, Narrow Channels, and Counterions

    KAUST Repository

    Pham, Tony

    2015-03-04

    © 2015 American Chemical Society. Grand canonical Monte Carlo (GCMC) simulations of hydrogen sorption were performed in In-soc-MOF, a charged metal-organic framework (MOF) that contains In3O trimers coordinated to 5,5′-azobis(1,3-benzenedicarboxylate) linkers. The MOF contains nitrate counterions that are located in carcerand-like capsules of the framework. This MOF was shown to have a high hydrogen uptake at 77 K and 1.0 atm. The simulations were performed with a potential that includes explicit many-body polarization interactions, which were important for modeling gas sorption in a charged/polar MOF such as In-soc-MOF. The simulated hydrogen sorption isotherms were in good agreement with experiment in this challenging platform for modeling. The simulations predict a high initial isosteric heat of adsorption, Qst, value of about 8.5 kJ mol-1, which is in contrast to the experimental value of 6.5 kJ mol-1 for all loadings. The difference in the Qst behavior between experiment and simulation is attributed to the fact that, in experimental measurements, the sorbate molecules cannot access the isolated cages containing the nitrate ions, the most energetically favorable site in the MOF, at low pressures due to an observed diffusion barrier. In contrast, the simulations were able to capture the sorption of hydrogen onto the nitrate ions at low loading due to the equilibrium nature of GCMC simulations. The experimental Qst values were reproduced in simulation by blocking access to all of the nitrate ions in the MOF. Furthermore, at 77 K, the sorbed hydrogen molecules were reminiscent of a dense fluid in In-soc-MOF starting at approximately 5.0 atm, and this was verified by monitoring the isothermal compressibility, βT, values. The favorable sites for hydrogen sorption were identified from the polarization distribution as the nitrate ions, the In3O trimers, and the azobenzene

  6. Surfactant-thermal method to synthesize a new Zn(II)-trimesic MOF with confined Ru(bpy){sub 3}{sup 2+} complex

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hui [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Gao, Junkuo, E-mail: jkgao@zstu.edu.cn [The Key laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Wang, Jiangpeng; Qian, Xuefeng [The Key laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Song, Ruijing; Cui, Yuanjing; Yang, Yu [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Qian, Guodong, E-mail: gdqian@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China)

    2015-03-15

    A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy){sub 3}{sup 2+} (RuBpy) complex by using surfactant PEG 400 as reaction medium. The RuBpy molecules were encapsulated between the 2-D sheets in ZJU-100. ZJU-100 showed bathochromic shift in the steady-state emission spectrum and increased emission lifetimes relative to RuBpy molecules. The extended lifetime is attributed to the reduced nonradiative decay rate due to the stabilization of RuBpy within the rigid MOF framework. These results represent the first example of MOF with confined complex synthesized by surfactant, indicating that the surfactant-thermal method could offer exciting opportunities for preparing new MOFs host/guest materials with novel structures and interesting luminescent properties. - Graphical abstract: A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy){sub 3}{sup 2+} (RuBpy) complex by using surfactant PEG 400 as reaction medium. - Highlights: • Surfactant-thermal synthesis of crystalline metal-organic framework host/guest materials. • RuBpy molecules were encapsulated between the 2-D sheets of MOFs. • Extended lifetime is observed due to the stabilization of RuBpy within the rigid MOF framework.

  7. Novel symmetrical coralloid Cu 3D superstructures: Solid-state synthesis from a Cu-carboxylate MOF and their in-situ thermal conversion

    International Nuclear Information System (INIS)

    We describe here a one-step solid-state process for the synthesis of metal three-dimensional (3D) superstructures from a metal-organic framework (MOF). Novel symmetrical coralloid Cu 3D superstructures with surface interspersed with clusters of Cu nanoparticles were successfully synthesized by thermolysis of the [Cu3(btc)2] (btc=benzene-1,3,5-tricarboxylato) MOF in a one-end closed horizontal tube furnace (OCTF). The obtained products were characterized by TGA, FT-IR, XRD, EDX, SEM, TEM, HRTEM and SAED. Different reaction conditions were discussed. Furthermore, the synthesized Cu samples were converted into CuO microstructures by in-situ calcination in the air. In addition, the possible formation mechanism was also proposed. This method is a simple and facile route, which builds a direct linkage between metal-carboxylate MOF crystals and metal nano- or microstructures and also opens a new application field of MOFs. - Graphical abstract: Novel symmetrical coralloid Cu 3D superstructures were synthesized by thermolysis of the [Cu3(btc)2] (btc=benzene-1,3,5-tricarboxylato) MOF microcrystals in a one-end closed horizontal tube furnace (OCTF).

  8. The effect of structural and energetic parameters of MOFs and COFs towards the improvement of their hydrogen storage properties

    International Nuclear Information System (INIS)

    Open-framework materials have been proposed as potential materials for hydrogen storage. Metal-organic framework (MOF) and covalent-organic framework (COF) materials are under extensive study to discover their storage abilities. In particular the IRMOF family of materials have been considered as ideal to study the effect of different factors that affect the hydrogen storage capacity. In this paper, we analyse the effect of different factors such as surface area, pore volume and the interaction of hydrogen with the molecular framework on the hydrogen uptake of such materials. Through this analysis we propose guidelines to enhance hydrogen storage capacity of already synthesized materials and recommend advanced materials for this application.

  9. An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation.

    Science.gov (United States)

    Doan, Tan L H; Dao, Thong Q; Tran, Hai N; Tran, Phuong H; Le, Thach N

    2016-05-01

    A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles. PMID:27064371

  10. One-step growth of lanthanoid metal-organic framework (MOF) films under solvothermal conditions for temperature sensing.

    Science.gov (United States)

    Liu, Xue; Fu, Wentian; Bouwman, Elisabeth

    2016-05-25

    A one-step direct solvothermal synthesis of an Ln metal-organic framework (MOF) film is reported. The LnHL (Ln = Tb and Gd) films that were deposited on a Gd2O3 subtrate are continuous and smooth. The Gd0.9Tb0.1HL film can be used as a ratiometric thermometer, showing good linear behaviour in the temperature range of 110-250 K with a sensitivity up to 0.8% K(-1). PMID:27147478

  11. Optimized manufacturable porous materials

    DEFF Research Database (Denmark)

    Andreassen, Erik; Andreasen, Casper Schousboe; Jensen, Jakob Søndergaard;

    to include manufacturing constraints in the optimization. This work focuses on incorporating the manufacturability into the optimization procedure, allowing the resulting material structure to be manufactured directly using rapid manufacturing techniques, such as selective laser melting....../sintering (SLM/S). The available manufacturing methods are best suited for porous materials (one constituent and void), but the optimization procedure can easily include more constituents. The elasticity tensor is found from one unit cell using the homogenization method together with a standard finite element...... (FE) discretization. The distribution of the material in the unit cell is optimized according to a given objective (e.g. maximum bulk modulus or minimum Poisson’s ratio) and some given constraints (e.g. isotropy) using topology optimization. The manufacturability is achieved using various filtering...

  12. Filtration in Porous Media

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied to...... understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

  13. Convection in porous media

    CERN Document Server

    Nield, Donald A

    1992-01-01

    This book provides a user-friendly introduction to the topic of convection in porous media The authors as- sume that the reader is familiar with the basic elements of fluid mechanics and heat transfer, but otherwise the book is self-contained The book will be useful both as a review (for reference) and as a tutorial work, suitable as a textbook in a graduate course or seminar The book brings into perspective the voluminous research that has been performed during the last two decades The field has recently exploded because of worldwide concern with issues such as energy self-sufficiency and pollution of the environment Areas of application include the insulation of buildings and equipment, energy storage and recovery, geothermal reservoirs, nuclear waste disposal, chemical reactor engineering, and the storage of heat-generating materials such as grain and coal Geophysical applications range from the flow of groundwater around hot intrusions to the stability of snow against avalanches

  14. Liquid-Phase Epitaxy Effective Encapsulation of Lanthanide Coordination Compounds into MOF Film with Homogeneous and Tunable White-Light Emission.

    Science.gov (United States)

    Gu, Zhi-Gang; Chen, Zheng; Fu, Wen-Qiang; Wang, Fei; Zhang, Jian

    2015-12-30

    As a new family of hybrid inorganic-organic materials with large porosity, metal-organic frameworks (MOFs) have received attractive attention recently on encapsulating functional guest species. Although the encapsulation of luminescent guest into bulk MOFs can tune the luminescent property, the powder composite materials are limited to the application in optical sensors and devices. In the present work, we use a modified liquid-phase epitaxial (LPE) pump method for the fabrication of lanthanide coordination compounds (LCCs)-encapsulated MOF thin film on substrate with high encapsulation efficiency. The resultant composite film reveals an oriented and homogeneous composite film, in which a white light emission by tuning the LCCs of red, blue and green emission can be obtained. This strategy may open new perspectives for developing high-encapsulation-efficiency, oriented, and homogeneous solid-state lighting composite films in the application of optical sensors and devices. PMID:26641951

  15. Porous media geometry and transports

    CERN Document Server

    Adler, Pierre

    1992-01-01

    The goal of ""Porous Media: Geometry and Transports"" is to provide the basis of a rational and modern approach to porous media. This book emphasizes several geometrical structures (spatially periodic, fractal, and random to reconstructed) and the three major single-phase transports (diffusion, convection, and Taylor dispersion).""Porous Media"" serves various purposes. For students it introduces basic information on structure and transports. Engineers will find this book useful as a readily accessible assemblage of al the major experimental results pertaining to single-phase tr

  16. Adsorption of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates

    International Nuclear Information System (INIS)

    The functionalization of porous metal-organic frameworks (Cu3(BTC)2) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N2 and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies estimated by the modified Clausius-Clapeyron equation provided insight into the impact of POMs and alkali metal cations on the adsorption of VOCs. The introduction of POMs not only improved the stability, but also brought the increase of adsorption capacity by strengthening the interaction with gas molecules. Furthermore, the exchanged alkali metal cations acted as active sites to interact with adsorbates and enhanced the adsorption of VOCs. - Graphical Abstract: The adsorption behavior of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates has been systematically evaluated. Highlights: → Functionalization of MOFs was achieved by incorporating Keggin-type POMs. → Introduction of POMs improved the thermal stability and adsorption capacity. → Alkali metal ion-exchange modified the inclusion state and also enhanced the adsorption. → Adsorption enthalpies were estimated to study the impact of POMs and alkali metal cations.

  17. An interpenetrated pillared-layer MOF: Synthesis, structure, sorption and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Li-Na [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Zhao, Yang [Research and Development Department, Zhejiang Quhua Fluorine Chemistry Co., Ltd., Zhejiang 324004 (China); Hou, Lei, E-mail: lhou2009@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Cui, Lin; Wang, Hai-Hua; Wang, Yao-Yu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China)

    2014-02-15

    A new three-dimensional porous framework [Co{sub 2}(bpdc){sub 2}(H{sub 2}bpz)]∙2(DMF)·5(H{sub 2}O) (1) (H{sub 2}bpdc=4,4′-biphenyldicarboxylic acid, H{sub 2}bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole) has been solvothermally synthesized by employing mixed H{sub 2}bpdc and H{sub 2}bpz ligands. 1 is a pillared-layer framework based on a binuclear paddle-wheel Co{sub 2}(O{sub 2}C-R){sub 4} cluster, and exhibits a 2-fold interpenetrated 6-connected pcu topology. H{sub 2}bpz bridges Co{sub 2}(O{sub 2}C-R){sub 4} clusters with an angular coordination configuration to form interesting left- and right-handed helical chains. 1 possesses a two-dimensional porous system decorated by uncoordinated pyrazole –NH groups of H{sub 2}bpz, leading to high adsorption selectivities for CO{sub 2} over N{sub 2} and H{sub 2}. In addition, the strong antiferromagnetic interactions between the Co{sup 2+} ions in cluster were observed. - Graphical abstract: A new pillared-layer porous framework has been constructed by paddle-wheel Co{sub 2}(O{sub 2}C-R){sub 4} cluster and H{sub 2}bpdc–H{sub 2}bpz mixed ligands, displaying adsorption selectivity and antiferromagnetic properties. Display Omitted - Highlights: • We present a new pillared-layer framework based on paddle-wheel Co{sub 2}(O{sub 2}C-R){sub 4} cluster. • The framework possesses a 2-fold interpenetrated pcu topology. • The framework displays adsorption selectivity and antiferromagnetic properties.

  18. An interpenetrated pillared-layer MOF: Synthesis, structure, sorption and magnetic properties

    International Nuclear Information System (INIS)

    A new three-dimensional porous framework [Co2(bpdc)2(H2bpz)]∙2(DMF)·5(H2O) (1) (H2bpdc=4,4′-biphenyldicarboxylic acid, H2bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole) has been solvothermally synthesized by employing mixed H2bpdc and H2bpz ligands. 1 is a pillared-layer framework based on a binuclear paddle-wheel Co2(O2C-R)4 cluster, and exhibits a 2-fold interpenetrated 6-connected pcu topology. H2bpz bridges Co2(O2C-R)4 clusters with an angular coordination configuration to form interesting left- and right-handed helical chains. 1 possesses a two-dimensional porous system decorated by uncoordinated pyrazole –NH groups of H2bpz, leading to high adsorption selectivities for CO2 over N2 and H2. In addition, the strong antiferromagnetic interactions between the Co2+ ions in cluster were observed. - Graphical abstract: A new pillared-layer porous framework has been constructed by paddle-wheel Co2(O2C-R)4 cluster and H2bpdc–H2bpz mixed ligands, displaying adsorption selectivity and antiferromagnetic properties. Display Omitted - Highlights: • We present a new pillared-layer framework based on paddle-wheel Co2(O2C-R)4 cluster. • The framework possesses a 2-fold interpenetrated pcu topology. • The framework displays adsorption selectivity and antiferromagnetic properties

  19. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework.

    Science.gov (United States)

    Demir, Selvan; Brune, Nicholas K; Van Humbeck, Jeffrey F; Mason, Jarad A; Plakhova, Tatiana V; Wang, Shuao; Tian, Guoxin; Minasian, Stefan G; Tyliszczak, Tolek; Yaita, Tsuyoshi; Kobayashi, Tohru; Kalmykov, Stepan N; Shiwaku, Hideaki; Shuh, David K; Long, Jeffrey R

    2016-04-27

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr(2+), Fe(3+), Nd(3+), and Am(3+), from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  20. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

    Science.gov (United States)

    2016-01-01

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr2+, Fe3+, Nd3+, and Am3+, from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  1. Solid-State NMR Spectroscopy of Metal–Organic Framework Compounds (MOFs

    Directory of Open Access Journals (Sweden)

    Stefan Kaskel

    2012-11-01

    Full Text Available Nuclear Magnetic Resonance (NMR spectroscopy is a well-established method for the investigation of various types of porous materials. During the past decade, metal–organic frameworks have attracted increasing research interest. Solid-state NMR spectroscopy has rapidly evolved into an important tool for the study of the structure, dynamics and flexibility of these materials, as well as for the characterization of host–guest interactions with adsorbed species such as xenon, carbon dioxide, water, and many others. The present review introduces and highlights recent developments in this rapidly growing field.

  2. Application of a novel 2D cadmium(II)-MOF in the formation of a photo-switch with a substantial on-off ratio.

    Science.gov (United States)

    Roy, Sumit; Dey, Arka; Ray, Partha Pratim; Ortega-Castro, Joaquín; Frontera, Antonio; Chattopadhyay, Shouvik

    2015-08-21

    A novel thiocyanate bridged 2D MOF, [CdL(μ-1,3-SCN)2]n, [HL = 2-(2-(ethylamino)ethyliminomethyl)-6-ethoxyphenol] has been synthesized and characterized by X-ray crystallography. The band gap of the synthesized material in the solid state has been determined by experimental measurements and compared with the theoretical value obtained from DFT calculations. For the first time, the single crystal X-ray crystallography of a MOF has been reported along with its applicability in photosensitive devices. PMID:26176024

  3. Porous substrates filled with nanomaterials

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.; Stadermann, Michael

    2014-08-19

    A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

  4. Vibrational modes of porous silicon

    International Nuclear Information System (INIS)

    On the basis of theoretical and experimental investigations, the origin of room temperature photoluminescence (PL) from porous silicon is found to related to chemical complexes constituted the surface, in particular, SiHx, SiOx and SiOH groups. Ab initio atomic and molecular electronic structure calculations on select siloxane compounds were used for imitation of infrared (IR) spectra of porous silicon. These are compared to the IR spectra of porous silicon recorded by using Fourier Transform Infrared Spectroscopy (FTIR). In contrast to linear siloxane, the suggested circular siloxane terminated with linear siloxane structure is found to well-imitate the experimental spectra. These results are augmented with EDX (energy dispersive x-ray spectroscopy) measurements, which showed that the increase of SiOx content in porous silicon due to rapid oxidation process results in considerable decrease in PL peak intensity and a blue shift in the peak position. (author)

  5. Scattering characteristics from porous silicon

    International Nuclear Information System (INIS)

    Porous silicon layers come into existence as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet. In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from porous silicon and the origin of its photoluminescence are reviewed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include: different methods of porous silicon sample preparation; their photoluminescence, reflecting and scattering of light; determining different characteristics with respect to Si bulk

  6. Increase in Electrical Conductivity of MOF to Billion-Fold upon Filling the Nanochannels with Conducting Polymer.

    Science.gov (United States)

    Dhara, Barun; Nagarkar, Sanjog S; Kumar, Jitender; Kumar, Vikash; Jha, Plawan Kumar; Ghosh, Sujit K; Nair, Sunil; Ballav, Nirmalya

    2016-08-01

    Redox-active pyrrole (Py) monomers were intercalated into 1D nanochannels of [Cd(NDC)0.5(PCA)]·Gx (H2NDC = 2,6-napthalenedicarboxylic acid, HPCA = 4-pyridinecarboxylic acid, G = guest molecules) (1) - a fluorescent 3D MOF (λem = 385 nm). Subsequent activation of 1⊃Py upon immersing into iodine (I2) solution resulted in an increment of the bulk electrical conductivity by ∼9 orders of magnitude. The unusual increase in conductivity was attributed to the formation of highly oriented and conducting polypyrrole (PPy) chains inside 1D nanochannels and specific host-guest interaction in 1⊃PPy thereof. The Hall-effect measurements suggested 1⊃PPy to be an n-type semiconductor material with remarkably high-carrier density (η) of ∼1.5 × 10(17) cm(-3) and mobility (μ) of ∼8.15 cm(2) V(-1) s(-1). The fluorescence property of 1 was almost retained in 1⊃PPy with concomitant exciplex-type emission at higher wavelength (λem = 520 nm). The here-presented results on [MOF⊃Conducting Polymer] systems in general will serve as a prototype experiment toward rational design for the development of highly conductive yet fluorescent MOF-based materials for various optoelectronic applications. PMID:27404432

  7. Tuning of gate opening of an elastic layered structure MOF in CO2 sorption with a trace of alcohol molecules.

    Science.gov (United States)

    Cheng, Yan; Kajiro, Hiroshi; Noguchi, Hiroshi; Kondo, Atsushi; Ohba, Tomonori; Hattori, Yoshiyuki; Kaneko, Katsumi; Kanoh, Hirofumi

    2011-06-01

    It is important to tune the sorption behavior of metal-organic framework (MOF) materials. Ethanol treatment on the hydrated form of [Cu(bpy)(2)(BF(4))(2)], which is a representative flexible MOF showing the fascinating gate phenomenon on CO(2) sorption, induces an easier dehydration and a significant decrease in the CO(2) gate pressure. The results of IR, X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS) measurements indicated that water molecules in the lattice of the hydrated form can be removed even at room temperature after the ethanol treatment and the basic 2D layered structure remains with a slight interlayer expansion. The results of thermogravimetric (TG) and gas chromatograph/mass spectrometry (GC/MS) analyses and of CO(2) sorptions indicated that the change of the gate phenomenon was caused by a trace of residual ethanol molecules included in the structure. Similar phenomena were observed on alcohols with different polarity and molecular size. PMID:21534550

  8. G9a-mediated methylation of ERα links the PHF20/MOF histone acetyltransferase complex to hormonal gene expression.

    Science.gov (United States)

    Zhang, Xi; Peng, Danni; Xi, Yuanxin; Yuan, Chao; Sagum, Cari A; Klein, Brianna J; Tanaka, Kaori; Wen, Hong; Kutateladze, Tatiana G; Li, Wei; Bedford, Mark T; Shi, Xiaobing

    2016-01-01

    The euchromatin histone methyltransferase 2 (also known as G9a) methylates histone H3K9 to repress gene expression, but it also acts as a coactivator for some nuclear receptors. The molecular mechanisms underlying this activation remain elusive. Here we show that G9a functions as a coactivator of the endogenous oestrogen receptor α (ERα) in breast cancer cells in a histone methylation-independent manner. G9a dimethylates ERα at K235 both in vitro and in cells. Dimethylation of ERαK235 is recognized by the Tudor domain of PHF20, which recruits the MOF histone acetyltransferase (HAT) complex to ERα target gene promoters to deposit histone H4K16 acetylation promoting active transcription. Together, our data suggest the molecular mechanism by which G9a functions as an ERα coactivator. Along with the PHF20/MOF complex, G9a links the crosstalk between ERα methylation and histone acetylation that governs the epigenetic regulation of hormonal gene expression. PMID:26960573

  9. Study on Reusable MOF Meta-modeling Framework%可复用MOF元建模框架的研究

    Institute of Scientific and Technical Information of China (English)

    兰庆国; 刘淑芬; 张欣佳

    2007-01-01

    在MDA场景下,元模型是实现平台无关模型和平台相关模型转换的核心.提出通过元层模型和模型层模型的Down-Up机制给出可复用的MOF元建模框架.元建模框架由MOF BootStrap模型自举,并且内置MOF Model,此框架可在任意多层元建模中复用.此外,给出了模型工程模型和模型迁移剪枝算法,并提出了采用模型工程统一对象空间实现模型实例复用的方法.此框架的研究对于指导具体建模工具的实现有重要意义.

  10. X-Nuclei NMR Self-Diffusion Studies in Mesoporous Silica Foam and Microporous MOF CuBTC

    Directory of Open Access Journals (Sweden)

    Frank Stallmach

    2012-04-01

    Full Text Available A standard X-observe NMR probe was equipped with a z-gradient coil to enable high-sensitivity pulsed field gradient NMR diffusion studies of Li+ and Cs+ cations of aqueous salt solutions in a high-porosity mesocellular silica foam (MCF and of CO2 adsorbed in metal-organic frameworks (MOF. The coil design and the necessary probe modifications, which yield pulsed field gradients of up to ±16.2Tm−1, are introduced. The system was calibrated at 2H resonance frequency and successfully applied for diffusion studies at 7Li, 23Na, 13C and 133Cs frequencies. Significant reductions of the diffusivities of the cations in LiClac and CsClac solution introduced into MCFs are observed. By comparison of the diffusion behavior with the bulk solutions, a tortuosity of the silica foam of 4.5 ± 0.6 was derived. Single component self-diffusion of CO2 and CH4 (measured by 1H NMR as well as self-diffusion of the individual components in CO2/CH4 mixtures was studied in the MOF CuBTC. The experimental results confirm high mobilities of the adsorbed gases and trends for diffusion separation factors predicted by MD simulations.

  11. G9a-mediated methylation of ERα links the PHF20/MOF histone acetyltransferase complex to hormonal gene expression

    Science.gov (United States)

    Zhang, Xi; Peng, Danni; Xi, Yuanxin; Yuan, Chao; Sagum, Cari A.; Klein, Brianna J.; Tanaka, Kaori; Wen, Hong; Kutateladze, Tatiana G.; Li, Wei; Bedford, Mark T.; Shi, Xiaobing

    2016-01-01

    The euchromatin histone methyltransferase 2 (also known as G9a) methylates histone H3K9 to repress gene expression, but it also acts as a coactivator for some nuclear receptors. The molecular mechanisms underlying this activation remain elusive. Here we show that G9a functions as a coactivator of the endogenous oestrogen receptor α (ERα) in breast cancer cells in a histone methylation-independent manner. G9a dimethylates ERα at K235 both in vitro and in cells. Dimethylation of ERαK235 is recognized by the Tudor domain of PHF20, which recruits the MOF histone acetyltransferase (HAT) complex to ERα target gene promoters to deposit histone H4K16 acetylation promoting active transcription. Together, our data suggest the molecular mechanism by which G9a functions as an ERα coactivator. Along with the PHF20/MOF complex, G9a links the crosstalk between ERα methylation and histone acetylation that governs the epigenetic regulation of hormonal gene expression. PMID:26960573

  12. Paddle Wheel Based Triazolyl Isophthalate MOFs: Impact of Linker Modification on Crystal Structure and Gas Sorption Properties.

    Science.gov (United States)

    Kobalz, Merten; Lincke, Jörg; Kobalz, Karolin; Erhart, Oliver; Bergmann, Jens; Lässig, Daniel; Lange, Marcus; Möllmer, Jens; Gläser, Roger; Staudt, Reiner; Krautscheid, Harald

    2016-03-21

    Syntheses and comprehensive characterization of two closely related series of isomorphous metal-organic frameworks (MOFs) based on triazolyl isophthalate linkers with the general formula ∞(3)[M2(R(1)-R(2)-trz-ia)2] (M = Cu, Zn) are presented. Using solvothermal synthesis and synthesis of microcrystalline materials on the gram scale by refluxing a solution of the starting materials, 11 MOFs are readily available for a systematic investigation of structure-property relationships. The networks of the two series are assigned to rutile (rtl) (1-4) and α-PbO2 (apo) (5-9) topology, respectively. Due to the orientation of the triazole substituents toward the cavities, both the pore volume and the pore diameter can be adjusted by choice of the alkyl substituents. Compounds 1-9 exhibit pronounced microporosity with calculated porosities of 31-53% and show thermal stability up to 390 °C as confirmed by simultaneous thermal analysis. Systematic investigation of adsorption properties by CO2 (298 K) and N2 (77 K) adsorption studies reveal remarkable network flexibility induced by alkyl substituents on the linker. Fine-tuning of the gate opening pressure and of the hysteresis shape is possible by adjusting the substitution pattern and by choice of the metal ion. PMID:26950305

  13. Multiscale porous fuel cell electrodes

    Science.gov (United States)

    Wen, Hao

    Porous electrodes are widely used in fuel cells to enhance electrode performance due to their high surface area. Increasingly, such electrodes are designed with both micro-scale and nano-scale features. In the current work, carbon based porous materials have been synthesized and utilized as bioelectrode support for biofuel cells, analysis of such porous electrodes via rotating disk electrode has been enhanced by a numerical model that considers diffusion and convection within porous media. Finally, porous perovskite metal oxide cathodes for solid oxide fuel cell have been modeled to simulate impedance response data obtained from symmetric cells. Carbon fiber microelectrodes (CFME) were fabricated to mimic the microenvironment of carbon fiber paper based porous electrodes. They were also miniature electrodes for small-scale applications. As observed by scanning electron microscopy (SEM), carbon nanotubes (CNTs) formed a homogeneously intertwined matrix. Biocatalysts can fully infiltrate this matrix to form a composite, with a significantly enhanced glucose oxidation current---that is 6.4 fold higher than the bare carbon fiber electrodes. Based on the CNT based porous matrix, polystyrene beads of uniform diameter at 500 nm were used as template to tune the porous structure and enhance biomolecule transport. Focused ion beam (FIB) was used to observe the morphology both at the surface and the cross-section. It has been shown that the template macro-pores enhanced the fuel transport and the current density has been doubled due to the improvement. Like commonly used rotating disk electrode, the porous rotating disk electrode is a system with analytically solved flow field. Although models were proposed previously with first order kinetics and convection as the only mass transport at high rotations, some recent findings indicated that diffusion could play an important role at all disk rotation rates. In the current proposed model, enzymatic kinetics that follow a Ping

  14. A Co3O4-embedded porous ZnO rhombic dodecahedron prepared using zeolitic imidazolate frameworks as precursors for CO2 photoreduction

    Science.gov (United States)

    Wang, Tao; Shi, Li; Tang, Jing; Malgras, Victor; Asahina, Shunsuke; Liu, Guigao; Zhang, Huabin; Meng, Xianguang; Chang, Kun; He, Jianping; Terasaki, Osamu; Yamauchi, Yusuke; Ye, Jinhua

    2016-03-01

    Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the precursor and the template to prepare metal oxides or carbon-based materials. For the first time in this paper, the core-shell ZIF-8@ZIF-67 crystals are thermally converted into porous ZnO@Co3O4 composites by combining a seed-mediated growth process with a two-step calcination. The designed porous ZnO@Co3O4 composites exhibited the highest photocatalytic activity with an excellent stability for the reduction of CO2 among the commonly reported composite photocatalysts. Their superior photocatalytic performance is demonstrated to be resulting from the unique porous structure of ZnO@Co3O4 and the co-catalytic function of Co3O4 which can effectively suppress the photocorrosion of ZnO.Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the precursor and the template to prepare metal oxides or carbon-based materials. For the first time in this paper, the core-shell ZIF-8@ZIF-67 crystals are thermally converted into porous ZnO@Co3O4 composites by combining a seed-mediated growth process with a two-step calcination. The designed porous ZnO@Co3O4 composites exhibited the highest photocatalytic activity with an excellent stability for the reduction of CO2 among the commonly reported composite photocatalysts. Their superior photocatalytic performance is demonstrated to be resulting from the unique porous structure of ZnO@Co3O4 and the co-catalytic function of Co3O4 which can effectively suppress the photocorrosion of ZnO. Electronic supplementary information (ESI) available: Additional TG and DTA curves, XRD patterns, SEM images, TEM images, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy and GC-MS spectra of the samples. See DOI: 10.1039/c5nr08747c

  15. Quest for anionic MOF membranes: Continuous sod -ZMOF membrane with Co2 adsorption-driven selectivity

    KAUST Repository

    Almaythalony, Bassem

    2015-02-11

    We report the fabrication of the first continuous zeolite-like metal-organic framework (ZMOF) thin-film membrane. A pure phase sod-ZMOF, sodalite topology, membrane was grown and supported on a porous alumina substrate using a solvothermal crystallization method. The absence of pinhole defects in the film was confirmed and supported by the occurrence of quantifiable time-lags, for all studied gases, during constant volume/variable pressure permeation tests. For both pure and mixed gas feeds, the sod-ZMOF-1 membrane exhibits favorable permeation selectivity toward carbon dioxide over relevant industrial gases such as H2, N2, and CH4, and it is mainly governed by favorable CO2 adsorption.

  16. A Chemical Route to Activation of Open Metal Sites in the Copper-Based Metal-Organic Framework Materials HKUST-1 and Cu-MOF-2.

    Science.gov (United States)

    Kim, Hong Ki; Yun, Won Seok; Kim, Min-Bum; Kim, Jeung Yoon; Bae, Youn-Sang; Lee, JaeDong; Jeong, Nak Cheon

    2015-08-12

    Open coordination sites (OCSs) in metal-organic frameworks (MOFs) often function as key factors in the potential applications of MOFs, such as gas separation, gas sorption, and catalysis. For these applications, the activation process to remove the solvent molecules coordinated at the OCSs is an essential step that must be performed prior to use of the MOFs. To date, the thermal method performed by applying heat and vacuum has been the only method for such activation. In this report, we demonstrate that methylene chloride (MC) itself can perform the activation role: this process can serve as an alternative "chemical route" for the activation that does not require applying heat. To the best of our knowledge, no previous study has demonstrated this function of MC, although MC has been popularly used in the pretreatment step prior to the thermal activation process. On the basis of a Raman study, we propose a plausible mechanism for the chemical activation, in which the function of MC is possibly due to its coordination with the Cu(2+) center and subsequent spontaneous decoordination. Using HKUST-1 film, we further demonstrate that this chemical activation route is highly suitable for activating large-area MOF films. PMID:26197386

  17. The optimal binding sites of CH4 and CO2 molecules on the metal-organic framework MOF-5: ONIOM calculations

    International Nuclear Information System (INIS)

    Optimal binding sites and its corresponding binding energies between MOF-5 clusters and small guest molecules, CH4 and CO2, were investigated using the ONIOM method with different levels of quantum chemical calculations. The clusters were validated using three different sizes of the MOF-5 clusters, SINGLE, DOUBLE and TRIPLE consisting of (Zn4O)2(COOCH3)10(COO)2C6H4, (Zn4O)3(COOCH3)14(COO)4(C6H4)2 and (Zn4O)4(COOCH3)18(COO)6(C6H4)3 units, respectively. Guest molecules were assigned to lie in the configurations parallel (-parallel ) and perpendicular (-perpendicular ) to linker (LINK) and corner (CORN) domains of the clusters. The ONIOM(MP2/6-31G**:HF/6-31G**) with the corrections due to the basis set superposition errors was found to be the optimal choice for the investigation of these systems. Strong effects of cluster size were found for the CO2/MOF-5 complexes, i.e., the SINGLE cluster is sufficient to represent interactions with CH4, but the interaction with CO2 requires the TRIPLE model. The optimal binding sites of guest molecules as well as their orientations in the cavity of the MOF-5 are CORN-perpendicular for both CH4 and CO2 with the corresponding binding energies of -3.64 and -9.27 kJ/mol, respectively

  18. New Carbon-Based Porous Materials with Increased Heats of Adsorption for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Snurr, Randall Q.; Hupp, Joseph T.; Kanatzidis, Mercouri G.; Nguyen, SonBinh T.

    2014-11-03

    . Only after modeling suggested record-breaking hydrogen uptake at 77 K did we proceed to synthesize, characterize, and test the material, ultimately yielding experimental results that agreed closely with predictions that were made before the material was synthesized. We also synthesized, characterized, and computationally simulated the behavior of two new materials displaying the highest experimental Brunauer−Emmett−Teller (BET) surface areas of any porous materials reported to date (∼7000 m2/g). Key to evacuating the initially solvent-filled materials without pore collapse, and thereby accessing the ultrahigh areas, was the use of a supercritical CO2 activation technique developed by our team. In our efforts to increase the hydrogen binding energy, we developed the first examples of “zwitterionic” metal-organic frameworks (MOFs). The two structures feature zwitterionic characteristics arising from N-heterocyclic azolium groups in the linkers and negatively charged Zn2(CO2)5 nodes. These groups interact strongly with the H2 quadrupole. High initial isosteric heats of adsorption for hydrogen were measured at low H2 loading. Simulations were used to determine the H2 binding sites, and results were compared with inelastic neutron scattering. In addition to MOFs, the project produced a variety of related materials known as porous organic frameworks (POFs), including robust catechol-functionalized POFs with tunable porosities and degrees of functionalization. Post-synthesis metalation was readily carried out with a wide range of metal precursors (CuII, MgII, and MnII salts and complexes), resulting in metalated POFs with enhanced heats of hydrogen adsorption compared to the starting nonmetalated materials. Isosteric heats of adsorption as high as 9.6 kJ/mol were observed, compared to typical values around 5 kJ/mol in unfunctionalized MOFs and POFs. Modeling played an important role throughout the project. For example, we used molecular simulations to determine that

  19. Arsenic Trioxide Reduces Global Histone H4 Acetylation at Lysine 16 through Direct Binding to Histone Acetyltransferase hMOF in Human Cells.

    Science.gov (United States)

    Liu, Da; Wu, Donglu; Zhao, Linhong; Yang, Yang; Ding, Jian; Dong, Liguo; Hu, Lianghai; Wang, Fei; Zhao, Xiaoming; Cai, Yong; Jin, Jingji

    2015-01-01

    Histone post-translational modification heritably regulates gene expression involved in most cellular biological processes. Experimental studies suggest that alteration of histone modifications affects gene expression by changing chromatin structure, causing various cellular responses to environmental influences. Arsenic (As), a naturally occurring element and environmental pollutant, is an established human carcinogen. Recently, increasing evidence suggests that As-mediated epigenetic mechanisms may be involved in its toxicity and carcinogenicity, but how this occurs is still unclear. Here we present evidence that suggests As-induced global histone H4K16 acetylation (H4K16ac) partly due to the direct physical interaction between As and histone acetyltransferase (HAT) hMOF (human male absent on first) protein, leading to the loss of hMOF HAT activity. Our data show that decreased global H4K16ac and increased deacetyltransferase HDAC4 expression occurred in arsenic trioxide (As2O3)-exposed HeLa or HEK293T cells. However, depletion of HDAC4 did not affect global H4K16ac, and it could not raise H4K16ac in cells exposed to As2O3, suggesting that HDAC4 might not directly be involved in histone H4K16 de-acetylation. Using As-immobilized agarose, we confirmed that As binds directly to hMOF, and that this interaction was competitively inhibited by free As2O3. Also, the direct interaction of As and C2CH zinc finger peptide was verified by MAIDI-TOF mass and UV absorption. In an in vitro HAT assay, As2O3 directly inhibited hMOF activity. hMOF over-expression not only increased resistance to As and caused less toxicity, but also effectively reversed reduced H4K16ac caused by As exposure. These data suggest a theoretical basis for elucidating the mechanism of As toxicity. PMID:26473953

  20. Reversible flexible structural changes in multidimensional MOFs by guest molecules (I{sub 2}, NH{sub 3}) and thermal stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang; Li, Libo; Yang, Jiangfeng; Wang, Shuang; Li, Jinping, E-mail: Jpli211@hotmail.com

    2015-03-15

    Three metal–organic frameworks (MOFs), [Cu(INA){sub 2}], [Cu(INA){sub 2}I{sub 2}] and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}], were synthesized with 3D, 2D, and 0D structures, respectively. Reversible flexible structural changes of these MOFs were reported. Through high temperature (60–100 °C) stimulation of I{sub 2} or ambient temperature stimulation of NH{sub 3}, [Cu(INA){sub 2}] (3D) converted to [Cu(INA){sub 2}I{sub 2}] (2D) and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}] (0D); as the temperature increased to 150 °C, the MOFs changed back to their original form. In this way, this 3D MOF has potential application in the capture of I{sub 2} and NH{sub 3} from polluted water and air. XRD, TGA, SEM, NH{sub 3}-TPD, and the measurement of gas adsorption were used to describe the changes in processes regarding the structure, morphology, and properties. - Graphical abstract: Through I{sub 2}, NH{sub 3} molecules and thermal stimulation, the three MOFs can achieve reversible flexible structural changes. Different methods were used to prove the flexible reversible changes. - Highlights: • [Cu(INA){sub 2}] can flexible transform to [Cu(INA){sub 2}I{sub 2}] and [Cu(INA){sub 2}(H{sub 2}O){sub 2}(NH{sub 3}){sub 2}] by adsorbing I{sub 2} or NH{sub 3}. • The reversible flexible transformation related to material source, temperature and concentration. • Potential applications for the capture of I{sub 2} and NH{sub 3} from polluted water or air.

  1. Controllable synthesis of dual-MOFs nanostructures for pH-responsive artemisinin delivery, magnetic resonance and optical dual-model imaging-guided chemo/photothermal combinational cancer therapy.

    Science.gov (United States)

    Wang, Dongdong; Zhou, Jiajia; Chen, Ruhui; Shi, Ruohong; Zhao, Gaozheng; Xia, Guoliang; Li, Ren; Liu, Zhenbang; Tian, Jie; Wang, Huijuan; Guo, Zhen; Wang, Haibao; Chen, Qianwang

    2016-09-01

    Theranostic nanoagents which integrate diagnostic and therapeutic moieties into a single platform have attracted broad attention in cancer therapy, however the development of more effective and less toxic diagnostic and therapeutic interventions is still of great urgency. Herein, novel core-shell PB@MIL-100(Fe) dual metal-organic-frameworks (d-MOFs) nanoparticles are fabricated and their combined theranostic effects in vitro and in vivo are investigated. The d-MOFs nanoparticles can serve as a T1-T2 dual-modal magnetic resonance imaging (MRI) contrast and fluorescence optical imaging (FOI) agent due to the existence of inner PB MOFs and outer MIL-100(Fe) MOFs. The artemisinin (a traditional Chinese anticancer medicine) with a high loading content of 848.4 mg/g is released from the d-MOFs upon tumor cellular endocytosis due to the pH-responsive degradation of outer MOFs in low pH lysosomes of tumor cells. Furthermore, the inner PB MOFs can be utilized for photothermal therapy due to its strong absorbance in NIR region. Under the guidance by such dual-modal imaging, in vivo photothermal and chemotherapy is finally carried out, achieving effective tumor ablation in an animal tumor model. Furthermore, histological analysis revealed that the drug delivery system had no obvious effect on the major organs of mice due to the low toxicity of both d-MOFs and artemisinin. The distinctive multimodal imaging capability, excellent synergistic therapy effect through the combined chemo-photothermal therapy together with the low toxicity of both d-MOFs and artemisinin endow the theranostic nanoagent a promising next generation of nanomedicine for efficient and safe cancer therapy. PMID:27240160

  2. Acoustic Absorption in Porous Materials

    Science.gov (United States)

    Kuczmarski, Maria A.; Johnston, James C.

    2011-01-01

    An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

  3. On strength of porous material

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1999-01-01

    irregularities only scattered MOE-MOR relations (clouds) can be established from which no really results can be read.For homogeneously produced porous materials, however, like modern ceramics and high performance concretes MOE-MOR relations can be presented which are reliable. The present paper contributes to......The question of non-destructive testing of porous materials has always been of interest for the engineering profession. A number of empirically based MOE-MOR relations between stiffness (Modulus Of Elasticity) and strength (Modulus OF Rupture) of materials have been established in order to control...... quality without damaging or destroying the material or the building component considered. The efficiency of MOE-MOR relations for this purpose depends very much on the homogeneity of porous material considered. For building materials like wood and concrete of normal or lower quality with a number of...

  4. On strength of porous material

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1999-01-01

    quality without damaging or destroying the material or the building component considered. The efficiency of MOE-MOR relations for this purpose depends very much on the homogeneity of porous material considered. For building materials like wood and concrete of normal or lower quality with a number of......The question of non-destructive testing of porous materials has always been of interest for the engineering profession. A number of empirically based MOE-MOR relations between stiffness (Modulus Of Elasticity) and strength (Modulus OF Rupture) of materials have been established in order to control...... irregularities only scattered MOE-MOR relations (clouds) can be established from which no really results can be read.For homogeneously produced porous materials, however, like modern ceramics and high performance concretes MOE-MOR relations can be presented which are reliable. The present paper contributes to...

  5. Porous microsphere and its applications

    Directory of Open Access Journals (Sweden)

    Cai Y

    2013-03-01

    Full Text Available Yunpeng Cai,1,2* Yinghui Chen,3* Xiaoyun Hong,2 Zhenguo Liu,1 Weien Yuan2 1Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 2School of Pharmacy, Shanghai JiaoTong University, 3Department of Neurology Jinshan Hospital, Fudan University, Shanghai, People's Republic of China *These authors contributed equally to this workAbstract: Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies.Keywords: pore, porosity, porogen, suspension polymerization, seed swelling, pulmonary drug delivery, tissue regeneration

  6. Formation of porous gas hydrates

    CERN Document Server

    Salamatin, Andrey N

    2015-01-01

    Gas hydrates grown at gas-ice interfaces are examined by electron microscopy and found to have a submicron porous texture. Permeability of the intervening hydrate layers provides the connection between the two counterparts (gas and water molecules) of the clathration reaction and makes further hydrate formation possible. The study is focused on phenomenological description of principal stages and rate-limiting processes that control the kinetics of the porous gas hydrate crystal growth from ice powders. Although the detailed physical mechanisms involved in the porous hydrate formation still are not fully understood, the initial stage of hydrate film spreading over the ice surface should be distinguished from the subsequent stage which is presumably limited by the clathration reaction at the ice-hydrate interface and develops after the ice grain coating is finished. The model reveals a time dependence of the reaction degree essentially different from that when the rate-limiting step of the hydrate formation at...

  7. Nonequilibrium Thermodynamics of Porous Electrodes

    CERN Document Server

    Ferguson, Todd R

    2012-01-01

    We review classical porous electrode theory and extend it to non-ideal active materials, including those capable of phase transformations. Using principles of non-equilibrium thermodynamics, we relate the cell voltage, ionic fluxes, and Faradaic charge-transfer kinetics to the variational electrochemical potentials of ions and electrons. The Butler-Volmer exchange current is consistently expressed in terms of the activities of the reduced, oxidized and transition states, and the activation overpotential is defined relative to the local Nernst potential. We also apply mathematical bounds on effective diffusivity to estimate porosity and tortuosity corrections. The theory is illustrated for a Li-ion battery with active solid particles described by a Cahn-Hilliard phase-field model. Depending on the applied current and porous electrode properties, the dynamics can be limited by electrolyte transport, solid diffusion and phase separation, or intercalation kinetics. In phase-separating porous electrodes, the model...

  8. Recognition of Acoustic Signals of Synchronous Motors with the Use of MoFS and Selected Classifiers

    Directory of Open Access Journals (Sweden)

    Glowacz Adam

    2015-08-01

    Full Text Available This paper proposes an approach based on acoustic signals for detecting faults appearing in synchronous motors. Acoustic signals of a machine were used for fault detection. These faults contained: broken coils and shorted stator coils. Acoustic signals were used to assess the usefulness of early fault diagnostic of synchronous motors. The acoustic signal recognition system was based on methods of data processing: normalization of the amplitude, Fast Fourier Transform (FFT, method of frequency selection (MoFS, backpropagation neural network, classifier based on words coding, and Nearest Neighbor classifier. A plan of study of acoustic signals of synchronous motors was proposed. Software of acoustic signal recognition of synchronous motors was implemented. Four states of a synchronous motor were used in analysis. A pattern creation process was carried out for 28 training samples of noise. An identification process was carried out for 60 test samples. This system can be used to diagnose synchronous motors and other electrical machines.

  9. External anion effect on the synthesis of new MOFs based on formate and a twisted divergent ligands

    Science.gov (United States)

    Lago, Ana Belén; Carballo, Rosa; Lezama, Luis; Vázquez-López, Ezequiel M.

    2015-11-01

    New copper(II) metal-organic compounds with the formulae [Cu3Cl(HCO2)5(SCS)3(H2O)2]·8H2O·EtOH (1) and [Cu3(HCO2)4(SCS)4(H2O)2](NO3)2·9H2O (2) (SCS=bis(4-pyridylthio)methane) have been synthesized after a careful study of the reaction of the SCS ligand with copper(II) formate. The compounds were obtained in the presence of sodium chloride and nitrate salts under microwave irradiation. The influence of the anion at different metal/anion ratios on the final architecture has been studied. The new chloride-MOF 1 has been characterized by electron paramagnetic resonance (EPR), magnetic properties and single crystal X-ray diffraction studies. The thermal stability and topological analysis have also been investigated.

  10. Construction and maintenace of porous asphalt

    OpenAIRE

    Kert, Gregor

    2012-01-01

    In improving traffic safety and reducing traffic noise road building experts from Slovenia and the world are faced with permeable surfaces - namely porous asphalt. There is hardly any water retention on road surfaces with the use of porous asphalt, what Slovenian engineers efficiently use on motorways where transverse profile changes its direction. Lately, porous asphalt is also being used for traffic noise reduction. However, porous road surface has some important disadvantages due to its...

  11. Photo-, electro- and cathodoluminescence of porous silicon

    International Nuclear Information System (INIS)

    The features of photoluminescence and electroluminescence in contact with oxide electrolyte as well as features of cathodoluminescence of porous silicon are investigated. The temporal evolution of electroluminescence of porous silicon is studied. We have also investigated cathodoluminescence from porous silicon at room temperature and the temperature of liquid nitrogen. The experimental results obtained confirm the presence of different radiation centers in porous silicon: with fast and slow kinetics

  12. Fabrication of porous electrospun nanofibres

    Science.gov (United States)

    Zhang, Y. Z.; Feng, Y.; Huang, Z.-M.; Ramakrishna, S.; Lim, C. T.

    2006-02-01

    Immiscible biopolymers of gelatin (Gt) and polycaprolactone (PCL) were first electrospun into a biomimicking composite fibre of Gt/PCL. Based on a phase separation study of the electrospun fibres, a leaching method was employed to generate 3D porous nanofibres by selectively removing the water soluble component of gelatin in a 37 °C aqueous solution of phosphate buffered saline. It was found that leaching treatment gave rise to a unique nanotopography containing grooves, ridges and elliptical pores on the surface as well as inside of the resultant individual nanofibres. Brunauer-Emmett-Teller (BET) area measurement indicated that the formed 3D porous fibres also brought in a pronounced increase of the surface area of fibres. The BET surface area of the porous fibres was observed to be about 2.4 times that of the precursor fibres, up to 15.84 m2 g-1 at its relatively large size of 800 nm diameter. The 3D porous fibres herein prepared could have considerable value for uses in developing highly integrated cell-scaffold tissue complexes and other industrial applications.

  13. Hydrostatic testing of porous assemblies

    Science.gov (United States)

    Bigelow, W. L.

    1968-01-01

    Pores of the material were plugged with dust particles suspended in water. The plugging material used was a standard test dust prepared as a slurry in distilled water. This technique provides a permanent high-integrity seal for porous material without affecting its physical properties, yet permitting pressure testing to verify structural adequacy.

  14. Porous Materials - Structure and Properties

    DEFF Research Database (Denmark)

    Nielsen, Anders

    The paper presents some viewpoints on the description of the pore structure and the modelling of the properties of the porous building materials. Two examples are given , where it has been possible to connect the pore structure to the properties: Shrinkage of autoclaved aerated concrete and the...... properties of lime mortar....

  15. Porous Materials - Structure and Properties

    DEFF Research Database (Denmark)

    Nielsen, Anders

    1997-01-01

    The paper presents some viewpoints on the description of the pore structure and the modelling of the properties of the porous building materials. Two examples are given , where it has been possible to connect the pore structure to the properties: Shrinkage of autoclaved aerated concrete and the...

  16. Porous silicon carbide (SIC) semiconductor device

    Science.gov (United States)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1996-01-01

    Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

  17. Introduction of π-complexation into porous aromatic framework for highly selective adsorption of ethylene over ethane

    KAUST Repository

    Li, Baiyan

    2014-06-18

    In this work, we demonstrate for the first time the introduction of π-complexation into a porous aromatic framework (PAF), affording significant increase in ethylene uptake capacity, as illustrated in the context of Ag(I) ion functionalized PAF-1, PAF-1-SO3Ag. IAST calculations using single-component-isotherm data and an equimolar ethylene/ethane ratio at 296 K reveal that PAF-1-SO3Ag shows exceptionally high ethylene/ethane adsorption selectivity (Sads: 27 to 125), far surpassing benchmark zeolite and any other MOF reported in literature. The formation of π-complexation between ethylene molecules and Ag(I) ions in PAF-1-SO 3Ag has been evidenced by the high isosteric heats of adsorption of C2H4 and also proved by in situ IR spectroscopy studies. Transient breakthrough experiments, supported by simulations, indicate the feasibility of PAF-1-SO3Ag for producing 99.95%+ pure C 2H4 in a Pressure Swing Adsorption operation. Our work herein thus suggests a new perspective to functionalizing PAFs and other types of advanced porous materials for highly selective adsorption of ethylene over ethane. © 2014 American Chemical Society.

  18. Structure and magnetism of a porous three-dimensional metal-organic framework based on planar tetranuclear copper(Ⅱ) cluster units

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A porous three-dimensional copper(Ⅱ) metal-organic framework (MOF) {[Cu2(tci)(OH)(pip)0.5(H2O)]·6H2O}n (1) [tci = tris (2-carboxyethyl)isocyanurate, pip = piperazine] has been generated under hydrothermal conditions at 120 °C. Single crystal X-ray diffraction reveals that the polymer exhibits a novel three-dimensional framework based on planar tetranuclear copper(Ⅱ) cluster units. The variable temperature magnetic susceptibility data in the range 2-280 K show antiferromagnetic spin-spin coupling in the tetranuclear unit in complex 1. A theoretical fitting of the magnetic data gives J values of -31.3 cm-1, -30.8 cm-1, and 13.5 cm-1.

  19. Symmetry-Guided Synthesis of Highly Porous Metal-Organic Frameworks with Fluorite Topology

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, MW; Chen, YP; Bosch, M; Gentle, T; Wang, KC; Feng, DW; Wang, ZYU; Zhou, HC

    2013-11-11

    Two stable, non-interpenetrated MOFs, PCN-521 and PCN-523, were synthesized by a symmetry-guided strategy. Augmentation of the 4-connected nodes in the fluorite structure with a rigid tetrahedral ligand and substitution of the 8-connected nodes by the Zr/Hf clusters yielded MOFs with large octahedral interstitial cavities. They are the first examples of Zr/Hf MOFs with tetrahedral linkers. PCN-521 has the largest BET surface area (3411 m(2) g(-1)), pore size (20.5 x 20.5 x 37.4 angstrom) and void volume (78.5%) of MOFs formed from tetrahedral ligands. This work not only demonstrates a successful implementation of rational design of MOFs with desired topology, but also provides a systematic way of constructing non-interpenetrated MOFs with high porosity.

  20. The next chapter in MOF pillaring strategies: Trigonal heterofunctional ligands to access targeted high-connected three dimensional nets, isoreticular platforms

    KAUST Repository

    Eubank, Jarrod F.

    2011-11-09

    A new pillaring strategy, based on a ligand-to-axial approach that combines the two previous common techniques, axial-to-axial and ligand-to-ligand, and permits design, access, and construction of higher dimensional MOFs, is introduced and validated. Trigonal heterofunctional ligands, in this case isophthalic acid cores functionalized at the 5-position with N-donor (e.g., pyridyl- or triazolyl-type) moieties, are designed and utilized to pillar pretargeted two-dimensional layers (supermolecular building layers, SBLs). These SBLs, based on edge transitive Kagomé and square lattices, are cross-linked into predicted three-dimensional MOFs with tunable large cavities, resulting in isoreticular platforms. © 2011 American Chemical Society.

  1. Kinetics of volatile fluoride desorption from granular sodium fluoride. Part II. Desorption of WF6, MoF6, and HF

    International Nuclear Information System (INIS)

    Desorption of tungsten hexafluoride, molybdenum hexafluoride and hydrogen fluoride sorbed on granulated sodium fluoride was studied in the temperature ranges 563-583 K, 463-483 K and 460-490 K respectively. It was ascertained that the process of WF6 and MoF6 desorption is limited by diffusion of the sorbate molecules from the bulk of sodium fluoride granules and it takes place in two stages. Chemical reaction of NaF · HF complex decomposition is the limiting stage of HF desorption. The values of apparent activation energy of WF6, MoF6 and HF desorption amounted to 95200 ± 2000 J/mol, 55000 ± 2500 J/mol and 88500 ± 1500 J/mol, respectively

  2. Infrared spectra of UF6, WF6, MoF6, and SF6 complexes with hydrogen fluoride in solid argon

    International Nuclear Information System (INIS)

    UF6, WF6, MoF6, and SF6 have been codeposited with hydrogen fluoride in excess argon at 12 K. The FTIR spectra of UF6 and HF revealed a strong UF6-HF complex absorption at 3,848 cm-1 along with a weak, broad band at 3,903 cm-1 due to the UF6-FH complex. Only one 1:2 complex with a UF6-HaF-HbF arrangement was detected at higher HF concentrations and sample annealings. Similarly, the HF interaction with tungsten hexafluoride formed two 1:1 complexes. However, the 3,884-cm-1 band due to the anti-hydrogen-bonded complex WF6-FH was considerably stronger than the WF6-FHb-FHa structure. The band positions and relative intensities for the MoF6 complexes with HF and DF were very comparable to their WF6 counterparts

  3. Molecular beam study of the reactions of K and Cs with UF6, WF6, MoF6, TeF6, and SeF6

    International Nuclear Information System (INIS)

    The reactions of K and Cs with UF6, WF6, MoF6, TeF6, SeF6, and SF6 at thermal energies have been investigated using crossed molecular beams. Except for SF6, these hexafluorides have remarkably high electron affinities. In fact, the electron affinities of MoF6, WF6, and UF6 exceed the ionization potentials of K and Cs so that spontaneous ion pair formation is energetically possible. In no case was a significant ion current observed. Instead, exchange reactions to form MF (and possibly MAF5) are observed. The measured product angular distributions were in all cases found to be consistent with the model of complex formation. However, substantial differences in the nature of the complex disintegration were noted

  4. Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

    KAUST Repository

    Chaieb, Sahraoui

    2015-04-09

    Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

  5. The determination of the equations of state of gaseous UF6, MoF6, WF6, ClF3 with dielectric method

    International Nuclear Information System (INIS)

    The technique for measuring dielectric constants was used to determine the molar polarization, non ideality and dipole moment of UF6, MoF6, WF6, CIF3. Comparisons are made between these non-ideality parameters and those obtained by Magnuson and volumetric method. It is demonstrated that dielectric non-ideality parameters of these gases are unsettled by an adsorption phenomena on the electrodes. (author)

  6. Giant Negative Area Compressibility Tunable in a Soft Porous Framework Material.

    Science.gov (United States)

    Cai, Weizhao; Gładysiak, Andrzej; Anioła, Michalina; Smith, Vincent J; Barbour, Leonard J; Katrusiak, Andrzej

    2015-07-29

    A soft porous material [Zn(L)2(OH)2]n·Guest (where L is 4-(1H-naphtho[2,3-d]imidazol-1-yl)benzoate, and Guest is water or methanol) exhibits the strongest ever observed negative area compressibility (NAC), an extremely rare property, as at hydrostatic pressure most materials shrink in all directions and few expand in one direction. This is the first NAC reported in metal-organic frameworks (MOFs), and its magnitude, clearly visible and by far the highest of all known materials, can be reversibly tuned by exchanging guests adsorbed from hydrostatic fluids. This counterintuitive strong NAC of [Zn(L)2(OH)2]n·Guest arises from the interplay of flexible [-Zn-O(H)-]n helices with layers of [-Zn-L-]4 quadrangular puckered rings comprising large channel voids. The compression of helices and flattening of puckered rings combine to give a giant piezo-mechanical response, applicable in ultrasensitive sensors and actuators. The extrinsic NAC response to different hydrostatic fluids is due to varied host-guest interactions affecting the mechanical strain within the range permitted by exceptionally high flexibility of the framework. PMID:25945394

  7. Scattering characteristics from porous silicon

    Directory of Open Access Journals (Sweden)

    R. Sabet-Dariani

    2000-12-01

    Full Text Available   Porous silicon (PS layers come into existance as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet.   In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from PS and the origin of its photoluminescence are reveiwed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include,different methods of PS sample preparation their photoluminescence, reflecting and scattering of light determining different characteristics with respect to Si bulk.

  8. POROUS WALL, HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to &apos

  9. Transport Upscaling in Porous Media

    OpenAIRE

    Nedreli, Anette Cathrine

    2014-01-01

    Numerical models are important for modeling what happens in porous media. In this thesis we will simulate the heat transport in geothermal reservoirs. Because these reservoirs are usually quite large, we will make a model that upgrids the fine scale reservoir into a coarser scale reservoir that has a smaller amount of grid cells. We will look at upgridding based on different indicators; Cartesian, permeability, velocity and time of flight. We need to upscale the energy equation so we can solv...

  10. Porous microsphere and its applications

    OpenAIRE

    Cai Y; Chen Y; Hong X; Liu Z; Yuan W

    2013-01-01

    Yunpeng Cai,1,2* Yinghui Chen,3* Xiaoyun Hong,2 Zhenguo Liu,1 Weien Yuan2 1Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 2School of Pharmacy, Shanghai JiaoTong University, 3Department of Neurology Jinshan Hospital, Fudan University, Shanghai, People's Republic of China *These authors contributed equally to this workAbstract: Porous microspheres have drawn great attention in the last two decades for their potential applications ...

  11. Optical gain in porous silicon

    Czech Academy of Sciences Publication Activity Database

    Herynková, Kateřina; Pelant, Ivan

    Cham : Springer International Publishing, 2014 - (Canham, L.), s. 345-354 ISBN 978-3-319-05743-9 R&D Projects: GA ČR GPP204/12/P235; GA AV ČR KJB100100903; GA AV ČR(CZ) IAA101120804 Institutional support: RVO:68378271 Keywords : silicon nanocrystals * porous silicon * optical gain Subject RIV: BM - Solid Matter Physics ; Magnetism

  12. Porous squeeze-film flow

    KAUST Repository

    Knox, D. J.

    2013-11-14

    © 2013 © The authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved. The squeeze-film flow of a thin layer of Newtonian fluid filling the gap between a flat impermeable surface moving under a prescribed constant load and a flat thin porous bed coating a stationary flat impermeable surface is considered. Unlike in the classical case of an impermeable bed, in which an infinite time is required for the two surfaces to touch, for a porous bed contact occurs in a finite contact time. Using a lubrication approximation, an implicit expression for the fluid layer thickness and an explicit expression for the contact time are obtained and analysed. In addition, the fluid particle paths are calculated, and the penetration depths of fluid particles into the porous bed are determined. In particular, the behaviour in the asymptotic limit of small permeability, in which the contact time is large but finite, is investigated. Finally, the results are interpreted in the context of lubrication in the human knee joint, and some conclusions are drawn about the contact time of the cartilage-coated femoral condyles and tibial plateau and the penetration of nutrients into the cartilage.

  13. Crystallization of copper(II) sulfate based minerals and MOF from solution: Chemical insights into the supramolecular interactions

    Indian Academy of Sciences (India)

    M Singh; D Kumar; J Thomas; A Ramanan

    2010-09-01

    Crystallization of solids, molecular or non-molecular from solution is a supramolecular reaction. Nucleation of a lattice structure at supersaturation can be conceived to result from a critical nucleus, a high energy intermediate (supramolecular transition state). Conceptualization of a structure for the critical nucleus in terms of aggregation of tectons through non-covalent interactions provides chemical insights into the architecture of a solid. The retrosynthetic analysis of copper-based minerals and materials offers an elegant description for the crystal packing. It addresses the influence of the geometry, functionality and reactivity of copper tecton(s) in directing a specific supramolecular aggregation. The mechanistic approach provides guiding principles to chemists to account for the experimentally crystallized solids and a platform to practice structure-synthesis correlation. Rationalization of the same composition with different atomic arrangements (polymorphs), compositional variation leading to different pseudopolymorphs, degree of hydration (anhydrous to hydrated), water clusters, role of solvent, etc. can all be justified on molecular basis. Also, the method gives predictive components including directions to synthesize new solids. In a nutshell, the paper is an attempt to generalize the crystallization of inorganic solids from solution by recognizing supramolecular interactions between metal tectons and gain insights for designing new MOF.

  14. Fe-based MOFs for efficient adsorption and degradation of acid orange 7 in aqueous solution via persulfate activation

    Science.gov (United States)

    Li, Xianghui; Guo, Weilin; Liu, Zhonghua; Wang, Ruiqin; Liu, Hua

    2016-04-01

    Fe-based metal-organic frameworks (MOFs) including MIL-101(Fe), MIL-100(Fe), MIL-53(Fe), and MIL-88B(Fe) prepared via a facile solvothermal process were introduced as both adsorbents and catalysts to generate powerful radicals from persulfate for acid orange 7 (AO7) removal in aqueous solution. Various catalysts were described and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectra. Because of the high specific surface area of the materials, we studied the adsorption isotherms of the four MILs by the fitting of Langmuir adsorption isotherm. Meanwhile, the catalytic activities in persulfate oxidation system were investigated. The results showed that the sequence of the materials ability in the combination of adsorption and degradation was MIL-101(Fe) > MIL-100(Fe) > MIL-53(Fe) > MIL-88B(Fe), which had a close connection with the activity of metal ion in active site of the catalysts and their different cages in size. Moreover, the reactive species in MILs/persulfate system were identified as sulfate radicals and hydroxyl radicals. The reaction mechanism for persulfate activation over MILs was also studied.

  15. Propagation of waves in porous media

    OpenAIRE

    Çorapçıoplu, M. Yavuz; Tuncay, Kağan

    1996-01-01

    Wave propagation in porous media is of interest in various diversified areas of science and engineering. The theory of the phenomenon has been studied extensively in soil mechanics, seismology, acoustics, earthquake engineering, ocean engineering, geophysics, and many other disciplines. This review presents a general survey of the literature within the context of porous media mechanics. Following a review of the Biot's theory of wave propagation in linear, elastic, fluid saturated porous medi...

  16. Nanostructures formed by displacement of porous silicon with copper: from nanoparticles to porous membranes

    OpenAIRE

    Bandarenka, Hanna; Redko, Sergey; Smirnov, Aleksandr; Panarin, Andrei; Terekhov, Sergei; Nenzi, Paolo; Balucani, Marco; Bondarenko, Vitaly

    2012-01-01

    The application of porous silicon as a template for the fabrication of nanosized copper objects is reported. Three different types of nanostructures were formed by displacement deposition of copper on porous silicon from hydrofluoric acid-based solutions of copper sulphate: (1) copper nanoparticles, (2) quasi-continuous copper films, and (3) free porous copper membranes. Managing the parameters of porous silicon (pore sizes, porosity), deposition time, and wettability of the copper sulphate s...

  17. Dynamics of H2 adsorbed in porous materials as revealed by computational analysis of inelastic neutron scattering spectra.

    Science.gov (United States)

    Pham, Tony; Forrest, Katherine A; Space, Brian; Eckert, Juergen

    2016-06-29

    The inelastic scattering of neutrons from adsorbed H2 is an effective and highly sensitive method for obtaining molecular level information on the type and nature of H2 binding sites in porous materials. While these inelastic neutron scattering (INS) spectra of the hindered rotational and translational excitations on the adsorbed H2 contain a significant amount of information, much of this can only be reliably extracted by means of a detailed analysis of the spectra through the utilization of models and theoretical calculations. For instance, the rotational tunneling transitions observed in the INS spectra can be related to a value for the barrier to rotation for the adsorbed H2 with the use of a simple phenomenological model. Since such an analysis is dependent on the model, it is far more desirable to use theoretical methods to compute a potential energy surface (PES), from which the rotational barriers for H2 adsorbed at a particular site can be determined. Rotational energy levels and transitions for the hindered rotor can be obtained by quantum dynamics calculations and compared directly with experiment with an accuracy subject only to the quality of the theoretical PES. In this paper, we review some of the quantum and classical mechanical calculations that have been performed on H2 adsorbed in various porous materials, such as clathrate hydrates, zeolites, and metal-organic frameworks (MOFs). The principal aims of these calculations have been the interpretation of the INS spectra for adsorbed H2 along with the extraction of atomic level details of its interaction with the host. We describe calculations of the PES used for two-dimensional quantum rotation as well as rigorous five-dimensional quantum coupled translation-rotation dynamics, and demonstrate that the combination of INS measurements and computational modeling can provide important and detailed insights into the molecular mechanism of H2 adsorption in porous materials. PMID:27160665

  18. Porous media heat transfer for injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  19. Ordered and disordered porous materials for nanofiltration application

    OpenAIRE

    Chowdhury, Sankhanilay Roy

    2005-01-01

    This Ph.D. dissertation elaborates on the use of porous materials in fluid separation technology. Two different types of porous materials, namely surfactant templated silica and alumina have been used to prepare flat plate geometry porous membranes.

  20. Spectroscopic properties of porous silicon

    International Nuclear Information System (INIS)

    The research of composition and spectroscopic properties of porous silicon (por-Si) surface has been done. Complex of photoluminescence (PL), electroluminescence (EL), Auger electron spectroscopy (AES), thermostimulated exoelectron emission (TSEE), electron spin resonance (ESR) spectroscopy methods have been applied to study the chemical composition of the surface, that plays a decisive role in light-emitting properties of pot-Si. The studies were done on the composition of por-Si real surface containing pure silicon or SiHy species mixture with silicon oxides and carbon atoms as well as background impurities of chlorine, fluorine and nitrogen. (author)

  1. Positronium chemistry in porous adsorbents

    International Nuclear Information System (INIS)

    Kinetic studies on the annihilation of orthopositronium in porous adsorbents have been performed using lifetime spectroscopy. The positron source applied was 22Na with 0.2 MBq activity. The adsorbents investigated were silica gels of different particle size and pore structure. The appearance of the long-lived component in the lifetime spectra can be explained by the diffusion of the orthopositronium into the pores affected by the particle size and the pore size of the adsorbent, the coverage on it and the chemical nature of the adsorbate. The long-term aim of the work is to determine and to explain these effects. (author)

  2. ZnO/porous-Si and TiO{sub 2}/porous-Si nanocomposite nanopillars

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong, E-mail: dong.wang@tu-ilmenau.de; Yan, Yong; Schaaf, Peter [Chair Materials for Electronics, Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, Gustav-Kirchhoff-Str. 5, 98693 Ilmenau (Germany); Sharp, Thomas [Oxford Instruments Plasma Technology Ltd., Yatton, Bristol BS49 4AP (United Kingdom); Schönherr, Sven; Ronning, Carsten [Institute for Solid State Physics, Friedrich Schiller University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Ji, Ran [SUSS MicroTec Lithography GmbH, Schleissheimer Str. 90, 85748 Garching (Germany)

    2015-01-01

    Porous Si nanopillar arrays are used as templates for atomic layer deposition of ZnO and TiO{sub 2}, and thus, ZnO/porous-Si and TiO{sub 2}/porous-Si nanocomposite nanopillars are fabricated. The diffusion of the precursor molecules into the inside of the porous structure occurs via Knudsen diffusion and is strongly limited by the small pore size. The luminescence of the ZnO/porous-Si nanocomposite nanopillars is also investigated, and the optical emission can be changed and even quenched after a strong plasma treatment. Such nanocomposite nanopillars are interesting for photocatalysis and sensors.

  3. Voltammetry at porous electrodes: A theoretical study

    OpenAIRE

    Barnes, Edward O; Chena, Xiaojun; Li, Peilin; Compton, Richard G.

    2014-01-01

    Theory is presented to simulate both chronoamperometry and cyclic voltammetry at porous electrodes fabricated by means of electro-deposition around spherical templates. A theoretical method to extract heterogeneous rate constants for quasireversible and irreversible systems is proposed by the approximation of decoupling of the diffusion within the porous electrode and of bulk diffusion to the electrode surface.

  4. Hydrodynamic dispersion within porous biofilms.

    Science.gov (United States)

    Davit, Y; Byrne, H; Osborne, J; Pitt-Francis, J; Gavaghan, D; Quintard, M

    2013-01-01

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher's equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels' network; (2) the solute's diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport. PMID:23410370

  5. Microelectromechanical pump utilizing porous silicon

    Science.gov (United States)

    Lantz, Jeffrey W.; Stalford, Harold L.

    2011-07-19

    A microelectromechanical (MEM) pump is disclosed which includes a porous silicon region sandwiched between an inlet chamber and an outlet chamber. The porous silicon region is formed in a silicon substrate and contains a number of pores extending between the inlet and outlet chambers, with each pore having a cross-section dimension about equal to or smaller than a mean free path of a gas being pumped. A thermal gradient is provided along the length of each pore by a heat source which can be an electrical resistance heater or an integrated circuit (IC). A channel can be formed through the silicon substrate so that inlet and outlet ports can be formed on the same side of the substrate, or so that multiple MEM pumps can be connected in series to form a multi-stage MEM pump. The MEM pump has applications for use in gas-phase MEM chemical analysis systems, and can also be used for passive cooling of ICs.

  6. A fine-tuned fluorinated MOF addresses the needs for trace CO2 removal and air capture using physisorption.

    KAUST Repository

    Bhatt, Prashant M.

    2016-07-08

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, from con-fined spaces (<0.5 %) and particularly from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal-organic framework (MOF), NbOFFIVE-1-Ni, with the proper pore system (size, shape and functionality), ideal for efficient and effective traces carbon dioxide removal. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm3.cm-3) for physical adsorbents at 400 ppm CO2 and 298 K. Practically, the NbOFFIVE-1-Ni affords the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in reference physical adsorbents but considerably lower than the conventional chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2-selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on the NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2-selectivity under practical carbon capture conditions. Pertinently, the no-table hydrolytic stability positions the NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces.

  7. Thermodynamic Study of CO2 Sorption by Polymorphic Microporous MOFs with Open Zn(II) Coordination Sites.

    Science.gov (United States)

    Ahrenholtz, Spencer R; Landaverde-Alvarado, Carlos; Whiting, Macauley; Lin, Shaoyang; Slebodnick, Carla; Marand, Eva; Morris, Amanda J

    2015-05-01

    Two Zn-based metal organic frameworks have been prepared solvothermally, and their selectivity for CO2 adsorption was investigated. In both frameworks, the inorganic structural building unit is composed of Zn(II) bridged by the 2-carboxylate or 5-carboxylate pendants of 2,5-pyridine dicarboxylate (pydc) to form a 1D zigzag chain. The zigzag chains are linked by the bridging 2,5-carboxylates across the Zn ions to form 3D networks with formulas of Zn4(pydc)4(DMF)2·3DMF (1) and Zn2(pydc)2(DEF) (2). The framework (1) contains coordinated DMF as well as DMF solvates (DMF = N,N-dimethylformamide), while (2) contains coordinated DEF (DEF = N,N-diethylformamide). (1) displays a reversible type-I sorption isotherm for CO2 and N2 with BET surface areas of 196 and 319 m(2)/g, respectively. At low pressures, CO2 and N2 isotherms for (2) were not able to reach saturation, indicative of pore sizes too small for the gas molecules to penetrate. A solvent exchange to give (2)-MeOH allowed for increased CO2 and N2 adsorption onto the MOF surface with BET surface areas of 41 and 39 m(2)/g, respectively. The binding of CO2 into the framework of (1) was found to be exothermic with a zero coverage heat of adsorption, Qst(0), of −27.7 kJ/mol. The Qst(0) of (2) and (2)-MeOH were found to be −3 and −41 kJ/mol, respectively. The CO2/N2 selectivity for (1), calculated from the estimated KH at 296 K, was found to be 42. At pressures relevant to postcombustion capture, the selectivity was 14. The thermodynamic data are consistent with a mechanism of adsorption that involves CO2 binding to the unsaturated Zn(II) metal centers present in the crystal structures. PMID:25898142

  8. New MOF based on lithium tetrahydrofuran-2,3,4,5-tetracarboxylate: Its structure and conductivity behavior

    International Nuclear Information System (INIS)

    A novel metal–organic framework, [Li6(HTFTA)2(H2O)3]·3H2O (LiTFTA, H4TFTA is tetrahydrofuran-2,3,4,5-tetracarboxylic acid), has been synthesized under solvothermal conditions and its structure was determined by single-crystal X-ray diffraction studies. It has six different LiO4 tetrahedra which forms two kinds of tetranuclear clusters that are coordinated to the ligands and form an overall three-dimensional structure with channels running along the crystallographic a axis. Some of the carboxylate groups of the ligand moiety jut out into the channels and the channels are occupied by water molecules. The proton conductivity behavior of LiTFTA with respect to temperature and relative humidity was analyzed by our newly developed impedance data analysis method called a random-walk approach. The results were compared with the data obtained by an analysis using an equivalent electric circuit model. Based on the physical parameters obtained by the random-walk method and the known structure we suggested the mechanism of the proton conductivity in this material. The proton conduction proceeds most probably by a vehicle conduction mechanism which employs mainly water molecules of crystallization present in the channels of LiTFTA. The value of the diffusion coefficient increases with temperature whereas the number of charge carriers remains constant. On the other hand, both the number of charge carriers and diffusion coefficient increase with increasing relative humidity. - Graphical abstract: Structure of a new metal organic framework was determined and its ionic conductivity was evaluated using a random-walk approach. - Highlights: • Lithium tetrahydrofuran-2,3,4,5-tetracarboxylate is a MOF with water-filled pores. • The impedance spectra indicate that this material is ion conductive. • Conductivity was evaluated using a random walk approach. • The number of charge carriers and diffusion coefficient was determined

  9. Preparation and characterization of porous magnesium materials

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-qin; LIU Zi-li; ZHANG Xiao-hong; FENG Jun-dong; YU Ta-xi

    2006-01-01

    The proper spacer material and the preparation technology for biological compatible porous magnesium materials were explored by the powder metallurgy method, and microstructures, porosity and mechanical properties of sintered porous magnesium were investigated. The results show that compared with spacer materials of NH4CO3, NH3Cl and carbamide, NH4CO3 is the best one for preparation of sintered porous magnesium, and the worst one is NH3Cl. The isolated blind pores are formed mainly by the particle interval of the magnesium powders. Adding spacer material favors the formation of open pores, while has little contribution to the formation of blind pores. The overall porosity and porosity of open pore of the sintered porous magnesium increase with the increase of added spacer material, while decrease with the increase of the molding stress. The mechanical properties of sintered porous magnesium increase with decreasing addition of spacer material and increasing molding stress.

  10. Post-Synthesis Functionalization of Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Al Otaibi, Mona S.

    2014-07-01

    Solid porous materials are network materials that contain space void. Porous Organic Polymers (POPs) are porous materials, which are constructed from organic building blocks and exhibit large surface area with low densities. Due to these characteristics, POPs have attracted attentions because of their potential use in application such as gas storage and chemical separation. This thesis presents a study of the synthesis of novel POP being a network based on 2,5- dibromobenzaldehyde and 1,3,5-triethynylbenzene linked together via Sonogashira- Hagihara (SH) coupling. This network showed a relatively good surface area of 770 m2/g and total pore volume of 0.59 cc/g. In addition, it proved to be chemically and thermally stable, maintaining the thermal stability up to 350oC. In addition to synthesize novel aldehyde-POP network, it was also possible to post synthetically modify a network via one-step post synthetic functionalization by amine. Ethelynediamine (EDA), Diethylenetriamine (DETA), and Tris(2-aminoethyl)amine (Tris-amine) are three different amines used for aldehyde-POP functionalization. The produced networks were aminated via different amine species substitution the aldehyde group present within the network. Modification to these networks resulted in a decrease in surface area from 770 m2.g-1 to 333 m2.g-1, 162 m2.g-1, and 211 m2.g-1 in respective to EDA, DETA, and Tris-amine. Although the surface areas were decreased, the CO2 adsorption was enhanced as evidenced by the increase of Qst (i.e., from 25 to 45 kJ.mol-1 for DETA at low coverage). Our findings are expected to strengthen existing research areas of the influence of different type of amines (e.g aromatic amine) on CO2 adsorption. Although amine grafting has been studied in other systems (e.g., PAFs and MOFs), we are the first to reported amine functionalized POPs using a novel one-step amine grafting PSM procedure. Future research might extend to study the interaction between CO2 and amine species under

  11. Magnetism in a number of Metal Organic Frameworks (MOFs) with 1D and 3D characteristics: An experimental and analytical study

    Science.gov (United States)

    Hamida, Youcef

    Metal Organic Frameworks (MOFs) exhibit many excellent physical properties including magnetic properties for potential applications in devices. More importantly for the subject of this thesis, MOFs are ideal for the realization of low dimensional magnetism because of the large selection of ligands connecting magnetic centers in making the framework. The materials studied in this thesis include ten magnetic MOFs of the form M(L1)(L2) [M = Cu, Ni, Co, Fe, Mn; L1 = NDC, bpdc, BDC, BODC, N3; L2 = DMF, H2O, TED, bpy]. Polycrystalline powder samples as well as single crystal samples were synthesized. Their crystal structures were determined, and their magnetic and thermodynamic properties were measured and analyzed. Eight of these materials were characterized as 1D magnets and two as 3D magnets. In the 1D case it is found that above Tm [the temperature at which the magnetic susceptibility chi(T) has a peak] the magnetic behavior of MOFs (S ≥ 1) can be well described with the Classical Fisher Model (CFM). Near and below TC the spins take a more definite orientation than allowed for in the CFM and hence the Ising Model (IM) was used for fitting. Both CFM and IM yield fairly consistent intrachain couplings ( J) when applied in their appropriate temperature region. To estimate the interchain exchange (J'), the susceptibility for a magnetic chain in the mean field of neighboring chains is used. In all cases, as expected, the ratio of J to J' was less than 10%. The special case of Cu(N3)2bpy ( S = ½) was analyzed with the spin ½ IM. Although the specific heat data (Ctotal) for most of the 1D MOFs showed no clear phase transition, a low temperature fit to the electron-phonon specific heats yielded apparent heavy fermion-like gamma values on the order of several hundred mJ/mol K2. The lattice specific heat (Clattice) was estimated using a Debye-Einstein hybrid model. Subtracting Clattice from Ctotal, magnetic specific heat ( CM) with a broad peak characteristic of low

  12. Anisotropic elastic properties of flexible metal-organic frameworks: how soft are soft porous crystals?

    Science.gov (United States)

    Ortiz, Aurélie U; Boutin, Anne; Fuchs, Alain H; Coudert, François-Xavier

    2012-11-01

    We performed ab initio calculations of the elastic constants of five flexible metal-organic frameworks (MOFs): MIL-53(Al), MIL-53(Ga), MIL-47, and the square and lozenge structures of DMOF-1. Tensorial analysis of the elastic constants reveals a highly anisotropic elastic behavior, some deformation directions exhibiting very low Young's modulus and shear modulus. This anisotropy can reach a 400:1 ratio between the most rigid and weakest directions, in stark contrast to the case of nonflexible MOFs such as MOF-5 and ZIF-8. In addition, we show that flexible MOFs can display extremely large negative linear compressibility. These results uncover the microscopic roots of stimuli-induced structural transitions in flexible MOFs, by linking the local elastic behavior of the material and its multistability. PMID:23215398

  13. Screening for high-spin metal organic frameworks (MOFs): density functional theory study on DUT-8(M1,M2) (with Mi = V,…,Cu).

    Science.gov (United States)

    Schwalbe, Sebastian; Trepte, Kai; Seifert, Gotthard; Kortus, Jens

    2016-03-01

    We present a first principles study of low-spin (LS)/high-spin (HS) screening for 3d metal centers in the metal organic framework (MOF) DUT-8(Ni). Various density functional theory (DFT) codes have been used to evaluate numerical and DFT related errors. We compare highly accurate all-electron implementations with the widely used plane wave approach. We present electronically and magnetically stable DUT-8(Ni) HS secondary building units (SBUs). In this work we show how to tune the magnetic and electronic properties of the original SBU only by changing the metal centers. PMID:26922864

  14. Vibrational spectra and force constants of the anions MoOF5-, MoOF52-, MoF6-, and WOF5-

    International Nuclear Information System (INIS)

    The vibrational spectra of CsMoOF5, MWOF5 (M = K, Rb, Cs), K2MoOF5, K2MoOF5 . H2O, K2MoOF5 . KHF2, and MMoF5 (M = K, Cs) have been recorded and assigned. The vibrational frequencies were used to calculate MVFF constants for the ions MoOF5-, WOF5-, MoOF52-, and MoF6-. The stretching force constants are discussed relative to the bond properties. (author)

  15. Rotating frame nuclear double resonance of 95Mo and 183W with 19F in polycrystalline MoF6 and WF6

    International Nuclear Information System (INIS)

    A series of rotating-frame nuclear-double-resonance experiments was performed in which the NMR of the isotopes 95Mo (I=5/2, natural abundance 16%) and 183W (I=1/2, natural abundance 14%) in MoF6 and WF6 respectively were detected via the strong resonance signal of the abundant 19F nuclei. Resonance peaks of two-quanta transitions were observed for 183W-NMR (I=1/2) in WF6, a nonlinear behavior was discussed 95Mo

  16. Vapour pressures and phase transition enthalpies of the fluorides IF5, IF7, MoF6, WF6 and UF6

    International Nuclear Information System (INIS)

    An apparatus is described for measuring the vapour pressures of chemically agressive substances up to 2.5 bars and 350K. Experimental results are reported for the fluorides IF5, IF7, MoF6, WF6, and UF6 in the temperature range 190-345K. The data represented by a suitable analytical function, which was used to determine transition temperatures and enthalpies and also enthalpies of vaporization. Furthermore the experimental results are compared with theoretical calculations using a model for liquids, which has only xi and rsub(min) of the Lennard-Jones-12.6-pair potential function as adjustable parameters. (orig.)

  17. Photonic Crystal Sensors Based on Porous Silicon

    Directory of Open Access Journals (Sweden)

    Claudia Pacholski

    2013-04-01

    Full Text Available Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential.

  18. Solute transport through a deforming porous medium

    Science.gov (United States)

    Peters, Glen P.; Smith, David W.

    2002-06-01

    Solute transport through a porous medium is typically modelled assuming the porous medium is rigid. However, many applications exist where the porous medium is deforming, including, municipal landfill liners, mine tailings dams, and land subsidence. In this paper, mass balance laws are used to derive the flow and transport equations for a deforming porous medium. The equations are derived in both spatial and material co-ordinate systems. Solute transport through an engineered landfill liner is used as an illustrative example to show the differences between the theory for a rigid porous medium, and small and large deformation analysis of a deforming porous medium. It is found that the large deformation model produces shorter solute breakthrough times, followed by the small deformation model, and then the rigid porous medium model. It is also found that it is important to include spatial and temporal void ratio variations in the large deformation analysis. It is shown that a non-linear large deformation model may greatly reduce the solute breakthrough time, compared to a standard transport analysis typically employed by environmental engineers.

  19. Hydrodynamic dispersion within porous biofilms

    KAUST Repository

    Davit, Y.

    2013-01-23

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher\\'s equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels\\' network; (2) the solute\\'s diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport. © 2013 American Physical Society.

  20. Additive manufacturing technologies of porous metal implants

    Directory of Open Access Journals (Sweden)

    Yang Quanzhan

    2014-06-01

    Full Text Available Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the significant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM and electron beam melting technology (EBM are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and fine structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  1. Additive manufacturing technologies of porous metal implants

    Institute of Scientific and Technical Information of China (English)

    Zhou Linxi; Yang Quanzhan; Zhang Guirong; Zhao Fangxin; Shen Gang; Yu Bo

    2014-01-01

    Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the signiifcant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM) and electron beam melting technology (EBM) are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and ifne structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  2. Tritium transport in lithium ceramics porous media

    Energy Technology Data Exchange (ETDEWEB)

    Tam, S.W.; Ambrose, V.

    1991-12-31

    A random network model has been utilized to analyze the problem of tritium percolation through porous Li ceramic breeders. Local transport in each pore channel is described by a set of convection-diffusion-reaction equations. Long range transport is described by a matrix technique. The heterogeneous structure of the porous medium is accounted for via Monte Carlo methods. The model was then applied to an analysis of the relative contribution of diffusion and convective flow to tritium transport in porous lithium ceramics. 15 refs., 4 figs.

  3. Tritium transport in lithium ceramics porous media

    Energy Technology Data Exchange (ETDEWEB)

    Tam, S.W.; Ambrose, V.

    1991-01-01

    A random network model has been utilized to analyze the problem of tritium percolation through porous Li ceramic breeders. Local transport in each pore channel is described by a set of convection-diffusion-reaction equations. Long range transport is described by a matrix technique. The heterogeneous structure of the porous medium is accounted for via Monte Carlo methods. The model was then applied to an analysis of the relative contribution of diffusion and convective flow to tritium transport in porous lithium ceramics. 15 refs., 4 figs.

  4. A new stereolithography experimental porous flow device

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, D.M.; Ahmadi, G. (Clarkson Univ., Potsdam, NY); Leonard, D. (Clarkson Univ., Potsdam, NY); Ferer, M.V.; Smith, D.H.

    2008-04-11

    A new method for constructing laboratory-scale porous media with increased pore-level variabilities for two-phase flow experiments is presented here. These devices have been created with stereolithography directly on glass, thus improving the stability of the model created with this precision rapid construction technique. The method of construction and improved parameters are discussed in detail, followed by a brief comparison of two-phase drainage results for air invasion into the water-saturated porous medium. Flow through the model porous medium is shown to substantiate theoretical fractal predictions.

  5. Porous Iron Structure Fabrication and Characterization

    OpenAIRE

    Kim, Taewoo

    2015-01-01

    Porous iron or steel structures can be useful as light- weight materials for transportation and structural applications. We have created such porous iron metallic structures by utilizing a composite of Fe2O3 nanoparticles(NPs), poly(methyl methacrylate)(PMMA) beads and polyethylene glycol(PEG) binder resin. Final optimized porous iron structure contains micro-pores of 15-20 µm size and nano-pores of 100-500 nm with strong connections between Fe grains. The results indicate that further effort...

  6. Tritium transport in lithium ceramics porous media

    International Nuclear Information System (INIS)

    A random network model has been utilized to analyze the problem of tritium percolation through porous Li ceramic breeders. Local transport in each pore channel is described by a set of convection-diffusion-reaction equations. Long range transport is described by a matrix technique. The heterogeneous structure of the porous medium is accounted for via Monte Carlo methods. The model was then applied to an analysis of the relative contribution of diffusion and convective flow to tritium transport in porous lithium ceramics. 15 refs., 4 figs

  7. Porous and Nanoporous Semiconductors and Emerging Applications

    Directory of Open Access Journals (Sweden)

    Helmut Föll

    2006-01-01

    Full Text Available Pores in single-crystalline semiconductors can be produced in a wide range of geometries and morphologies, including the “nanometer” regime. Porous semiconductors may have properties completely different from the bulk, and metamaterials with, for example, optical properties not encountered in natural materials are emerging. Possible applications of porous semiconductors include various novel sensors, but also more “exotic” uses as, for example, high explosives or electrodes for micro-fuel cells. The paper briefly reviews pore formation (including more applied aspects of large area etching, properties of porous semiconductors, and emerging applications.

  8. Modeling biologically reactive transport in porous media

    International Nuclear Information System (INIS)

    A one-dimensional biofilm-based reactive transport model is developed to simulate biologically mediated substrate metabolism and contaminant destruction in saturated porous media. The resulting equations are solved by a finite-difference based, three-level, operator-split approach. The numerical solution procedure is stable, easy-to-code, and computationally efficient. As an example problem, biological denitrification and fortuitous CT destruction processes in one-dimensional porous media is studied. The simulation results of the example problem show that the present model can be successfully used to predict biological processes and nutrient/contaminant transport in saturated porous media

  9. Metabolism and nutritional support during MOF%多脏器功能衰竭的代谢与营养支持

    Institute of Scientific and Technical Information of China (English)

    M.Adolph

    2001-01-01

    The problems of inflammation and infection leading to organ dysfunction and failure continue to be the major concerns after injury and operations and with the intensive care for many diseases and problems.When systemic inflammatory response syndrome (SIRS) goes to multiple organ dysfunction syndrome (MODS) and multiple organ failure (MOF),the mortality ecomes high,ranging from 30-80% depending on the number of failed organs.In MOF or MODS respiratory failure develops with the need for ventilaroty support,accompanied by circulatory instability with depression of cardiac output and a decrease in peripheral resistance,depression of the immune system,coagulation defects,gastrointestinal problems,a rising bilirubin denoting hepatic dysfunction and central nervous depression.The elevation in whole body protein turnover after sepsis and trauma usually is accompanied by an increase in metabolic rate Hepatic output of acute phase proteins rises,lean tissue is catabolized to provide energy substrates for wound and inflammatory tissue.Plasma proteins drop due to inhibition of hepathic synthesis,an increase in capillary permeability,and the dilutional effect of extracellular fluid expansion can be observed.Muscle protein synthesis seems to be decreased.These changes are driven by a combination of the counterregulatory hormones (catecholamines,glucagon,cortisol,growth hormone) and the direct and indirect actions fo the various inflammatory mediators (IL-1,IL-6,and TNF),prostaglandins and kallikreins.The changes in whole body protein turnover seen in MOF are similar to those described in overt sepsis and severe trauma:both synthesis and degradation are elevated,with a higher rate of degradation.This situation result in a loss of body mass, predominantly lean tissue.Although it is not oftern possible to identify the orgin of the “sepsis”,it must be reasonable to regard patients with MOF metabolically as “severely septic”.In recent years,the gastrointestinal tract was

  10. Immobilization of Polyoxometalate in the Metal-Organic Framework rht-MOF-1: Towards a Highly Effective Heterogeneous Catalyst and Dye Scavenger

    Science.gov (United States)

    Sun, Jing-Wen; Yan, Peng-Fei; An, Guang-Hui; Sha, Jing-Quan; Li, Guang-Ming; Yang, Guo-Yu

    2016-01-01

    A series of three remarkable complexes [PMo12O40]@[Cu6O(TZI)3(H2O)9]4·OH·31H2O (H3TZI = 5-tetrazolylisophthalic acid; denoted as HLJU-1, HLJU = Heilongjiang University), [SiMo12O40]@[Cu6O(TZI)3(H2O)9]4·32H2O (denoted as HLJU-2), and [PW12O40]@[Cu6O(TZI)3(H2O)6]4·OH·31H2O (denoted as HLJU-3) have been isolated by using simple one-step solvothermal reaction of copper chloride, 5-tetrazolylisophthalic acid (H3TZI), and various Keggin-type polyoxometalates (POMs), respectively. Crystal analysis of HLJU 1−3 reveals that Keggin-type polyoxoanions have been fitted snuggly in the cages of rht-MOF-1 (MOF: metal−organic framework) with large cell volume in a range of 87968−88800 Å3 and large pore volume of about 68%. HLJU 1–3 exhibit unique catalytic selectivity and reactivity in the oxidation of alkylbenzene with environmental benign oxidant under mild condition in aqueous phase as well as the uptake capacity towards organic pollutants in aqueous solution. PMID:27157290

  11. Immobilization of Polyoxometalate in the Metal-Organic Framework rht-MOF-1: Towards a Highly Effective Heterogeneous Catalyst and Dye Scavenger.

    Science.gov (United States)

    Sun, Jing-Wen; Yan, Peng-Fei; An, Guang-Hui; Sha, Jing-Quan; Li, Guang-Ming; Yang, Guo-Yu

    2016-01-01

    A series of three remarkable complexes [PMo12O40]@[Cu6O(TZI)3(H2O)9]4·OH·31H2O (H3TZI = 5-tetrazolylisophthalic acid; denoted as HLJU-1, HLJU = Heilongjiang University), [SiMo12O40]@[Cu6O(TZI)3(H2O)9]4·32H2O (denoted as HLJU-2), and [PW12O40]@[Cu6O(TZI)3(H2O)6]4·OH·31H2O (denoted as HLJU-3) have been isolated by using simple one-step solvothermal reaction of copper chloride, 5-tetrazolylisophthalic acid (H3TZI), and various Keggin-type polyoxometalates (POMs), respectively. Crystal analysis of HLJU 1-3 reveals that Keggin-type polyoxoanions have been fitted snuggly in the cages of rht-MOF-1 (MOF: metal-organic framework) with large cell volume in a range of 87968-88800 Å(3) and large pore volume of about 68%. HLJU 1-3 exhibit unique catalytic selectivity and reactivity in the oxidation of alkylbenzene with environmental benign oxidant under mild condition in aqueous phase as well as the uptake capacity towards organic pollutants in aqueous solution. PMID:27157290

  12. Phase Transformation Dynamics in Porous Battery Electrodes

    CERN Document Server

    Ferguson, Todd R

    2014-01-01

    Porous electrodes composed of multiphase active materials are widely used in Li-ion batteries, but their dynamics are poorly understood. Two-phase models are largely empirical, and no models exist for three or more phases. Using a modified porous electrode theory based on non-equilibrium thermodynamics, we show that experimental phase behavior can be accurately predicted from free energy models, without artificially placing phase boundaries or fitting the open circuit voltage. First, we simulate lithium intercalation in porous iron phosphate, a popular two-phase cathode, and show that the zero-current voltage gap, sloping voltage plateau and under-estimated exchange currents all result from size-dependent nucleation and mosaic instability. Next, we simulate porous graphite, the standard anode with three stable phases, and reproduce experimentally observed fronts of color-changing phase transformations. These results provide a framework for physics-based design and control for electrochemical systems with comp...

  13. Techniques for the Preparation of Porous Metals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Porous metals have been developed greatly and swiftly in recent years. In this paper, main types of these materials are described briefly, and their preparation methods are related primarily, with the purpose offering some clues for optimizing the producing technology.

  14. Fabrication of porous hydroxyapatite by foam technique

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Y.; Reusmaazran Yusof, M.; Besar, I.; Mustafa, R. [Malaysian Inst. for Nuclear Technology Research (MINT), Kajang, Selangor (Malaysia); Hing, K.A. [IRC in Biomedical Materials, Queen Mary and Westfield Coll., Univ. of London (United Kingdom)

    2002-07-01

    To improve healthcare, there is an increasing demand for bone replacement or bone graft materials towards treating and improving available parts of human body. Beside bioactive and biocompatible, synthetic hydroxyapatite can be produced with a porous structure to meet the requirement as a bone graft materials. In this work, the foam burnout technique was successfully used to produce porous hydroxyapatite. A polyurethane foam was soaked in a slip prepared by mixing hydroxyapatite powder with a binder solution prepared from polyvinylpyrolidone (PVP). After dried, the green structure was burnout and sintered. In this method, the prepared slip can influence the porous structure, hence gives rise to higher porosity and pore connectivity due to lower molecular weight binder (PVP). This paper presents the physical and morphological characteristics of the porous structure produced. (orig.)

  15. Photodetectors on the Basis of Porous Silicon

    Directory of Open Access Journals (Sweden)

    I.B. Olenych

    2012-11-01

    Full Text Available The paper studies the electrical characteristics of photodiode structures porous silicon – silicon substrates modified with molecules of iodine. Changes the nature of current-voltage characteristics obtained structures with symmetrical for straightening result of adsorption of iodine are revealed. It is studied the spectral characteristics of photoresponse in the 450-1100 nm wavelength range, its temperature dependence in the 125-325 K range and energy characteristics of photovoltaic structures based on porous silicon. A possible mechanism of influence of iodine adsorption on the electrical and photoelectrical properties of the structures of porous silicon – silicon substrates is proposed. The results extend the perspectives of porous silicon in photoelectronics.

  16. Adsorption on Highly Ordered Porous Alumina

    Science.gov (United States)

    Mistura, Giampaolo; Bruschi, Lorenzo; Lee, Woo

    2016-04-01

    Porous anodic aluminum oxide (AAO) is characterized by a regular arrangement of the pores with a narrow pore size distribution over extended areas, uniform pore depth, and solid pore walls without micropores. Thanks to significant improvements in anodization techniques, structural engineering of AAO allows to accurately tailor the pore morphology. These features make porous AAO an excellent substrate to study adsorption phenomena. In this paper, we review recent experiments involving the adsorption in porous AAO. Particular attention will be devoted to adsorption in straight and structured pores with a closed end which shed new light on fundamental issues like the origin of hysteresis in closed end pores and the nature of evaporation from ink-bottle pores. The results will be compared to those obtained in other synthetic materials like porous silicon and silica.

  17. Methane storage in advanced porous materials.

    Science.gov (United States)

    Makal, Trevor A; Li, Jian-Rong; Lu, Weigang; Zhou, Hong-Cai

    2012-12-01

    The need for alternative fuels is greater now than ever before. With considerable sources available and low pollution factor, methane is a natural choice as petroleum replacement in cars and other mobile applications. However, efficient storage methods are still lacking to implement the application of methane in the automotive industry. Advanced porous materials, metal-organic frameworks and porous organic polymers, have received considerable attention in sorptive storage applications owing to their exceptionally high surface areas and chemically-tunable structures. In this critical review we provide an overview of the current status of the application of these two types of advanced porous materials in the storage of methane. Examples of materials exhibiting high methane storage capacities are analyzed and methods for increasing the applicability of these advanced porous materials in methane storage technologies described. PMID:22990753

  18. Hydrogen in porous silicon — A review

    International Nuclear Information System (INIS)

    Highlights: • Particular role of hydrogen in silicon porosification technology is considered. • Hydrogen bonding and storage in porous silicon are discussed. • Hydrogen influence on luminescence and electrical properties are analysed. • Porous silicon H2 gas sensors and pH-metres are illustrated. • Hydrogen-assisted explosion and porous silicon grafting are reviewed. -- Abstract: This review is devoted to summarising the hydrogen-assisted properties and applications of porous silicon (PS). The role of hydrogen as an intermediate product in silicon porosification technology is accentuated. The regularities of hydrogen bonding in PS and its applications for hydrogen storage are listed. The models of hydrogen influence on luminescence and electrical properties of PS are analysed. The corresponding applications of PS for H2 gas sensors and pH metres are illustrated. Hydrogen-assisted explosion and grafting of PS are discussed. Such a review can be useful for the tailoring of PS properties

  19. Multiphase flow in fractured porous media

    Energy Technology Data Exchange (ETDEWEB)

    Firoozabadi, A.

    1995-02-01

    The major goal of this research project was to improve the understanding of the gas-oil two-phase flow in fractured porous media. In addition, miscible displacement was studied to evaluate its promise for enhanced recovery.

  20. Ultrasonic Nondestructive Characterization of Porous Materials

    Science.gov (United States)

    Yang, Ningli

    2011-12-01

    Wave propagation in porous media is studied in a wide range of technological applications. In the manufacturing industry, determining porosity of materials in the manufacturing process is required for strict quality control. In the oil industry, acoustic signals and seismic surveys are used broadly to determine the physical properties of the reservoir rock which is a porous media filled with oil or gas. In porous noise control materials, a precise prediction of sound absorption with frequency and evaluation of tortuosity are necessary. Ultrasonic nondestructive methods are a very important tool for characterization of porous materials. The dissertation deals with two types of porous media: materials with relatively low and closed porosity and materials with comparatively high and open porosity. Numerical modeling, Finite Element simulations and experimental characterization are all discussed in this dissertation. First, ultrasonic scattering is used to determine the porosity in porous media with closed pores. In order get a relationship between the porosity in porous materials and ultrasonic scattering independently and to increase the sensitivity to obtain scattering information, ultrasonic imaging methods are applied and acoustic waves are focused by an acoustic lens. To verify the technique, engineered porous acrylic plates with varying porosity are measured by ultrasonic scanning and ultrasonic array sensors. Secondly, a laser based ultrasonic technique is explored for predicting the mechanical integrity and durability of cementitious materials. The technique used involves the measurement of the phase velocity of fast and slow longitudinal waves in water saturated cement paste. The slow wave velocity is related to the specimen's tortuosity. The fast wave speed is dependent on the elastic properties of porous solid. Experimental results detailing the generation and detection of fast and slow wave waves in freshly prepared and aged water-saturated cement samples

  1. Additive manufacturing technologies of porous metal implants

    OpenAIRE

    Yang Quanzhan; Zhang Guirong

    2014-01-01

    Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the significant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of th...

  2. Phase Transformation Dynamics in Porous Battery Electrodes

    OpenAIRE

    Ferguson, Todd R.; Bazant, Martin Z.

    2014-01-01

    Porous electrodes composed of multiphase active materials are widely used in Li-ion batteries, but their dynamics are poorly understood. Two-phase models are largely empirical, and no models exist for three or more phases. Using a modified porous electrode theory based on non-equilibrium thermodynamics, we show that experimental phase behavior can be accurately predicted from free energy models, without artificially placing phase boundaries or fitting the open circuit voltage. First, we simul...

  3. Large deformations of a soft porous material

    OpenAIRE

    MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.

    2015-01-01

    Compressing a porous material will decrease the volume of the pore space, driving fluid out. Similarly, injecting fluid into a porous material can expand the pore space, distorting the solid skeleton. This poromechanical coupling has applications ranging from tissue mechanics to hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with Terzaghi's effective stress and linear elasticity in a linearized kinematic framework. Linear poroelasti...

  4. FACADE SYSTEM MADE OF POROUS MATERIALS

    OpenAIRE

    Zhukov Aleksey Dmitrievich; Chugunkov Aleksandr Viktorovich

    2012-01-01

    The proposed multi-component façade system is made of porous concretes employed both as bearing structures and for heat insulation and fireproofing purposes. The authors also provide their recommendations in respect of the mounting of the proposed façade system. The façade system considered in the article is composed of wall foam concrete blocks reinforced by basalt fibers (bearing elements of the structure), cellular concrete polystyrene (thermal insulation), and porous concrete (firepro...

  5. 3D Micromodels of Porous Structures

    Czech Academy of Sciences Publication Activity Database

    Pražák, Josef

    Praha : Ústav termomechaniky AV ČR, v. v. i., 2012 - (Jonáš, P.; Uruba, V.), s. 23-24 ISBN 978-80-87012-42-0. [Colloquium FLUID DYNAMICS 2012. Praha (CZ), 24.10.2012-26.10.2012] Institutional research plan: CEZ:AV0Z20760514 Keywords : porous media * modeling of porous mediua * micromodels Subject RIV: BK - Fluid Dynamics

  6. Radionuclide trap studies using porous carbon

    International Nuclear Information System (INIS)

    Towards import substitute, an attempt has been made to synthesise porous carbon by acidic sucrose solution route for use as trap material for cesium isotopes. The radionuclide trap experiments have been carried out to study the uptake of fission product cesium (137Cs) using reticulated vitreous carbon (RVC) and home made porous carbon (HMPC) in static sodium system. The trapping efficiency and distribution coefficient have been measured and compared. (author)

  7. Porous Cellulose Materials from Nano Fibrillated Cellulose

    OpenAIRE

    Cervin, Nicholas

    2012-01-01

    In the first part of this work a novel type of low-density, sponge-like material for the separation of mixtures of oil and water has been prepared by vapour deposition of hydrophobic silanes on ultra-porous nanocellulose aerogels. To achieve this, a highly porous (> 99 %) nanocellulose aerogel with high structural flexibility and robustness is first formed by freeze-drying an aqueous dispersion of the nanocellulose. The density, pore size distribution and wetting properties of the aerogel ...

  8. Introduction of π-Complexation into Porous Aromatic Framework for Highly Selective Adsorption of Ethylene over Ethane

    Energy Technology Data Exchange (ETDEWEB)

    Li, Baiyan; Zhang, Yiming; Krishna, Rajamani; Yao, Kexin; Han, Yu; Wu, Zili; Ma, Dingxuan; Shi, Zhan; Pham, Tony; Space, Brian; Liu, Jian; Thallapally, Praveen K.; Liu, Jun; Matthew, Chrzanowski; Ma, Shengqian

    2014-06-05

    We report herein a strategy of incorporating air stable Ag(I) ions into water stable, high surface area porous organic polymer (POP) affording significant increase in ethylene uptake capacity and extremely high Qst for ethylene (over 100 kJ/mol at low ethylene load-ing) as illustrated in the context of Ag(I) ion functionalized PAF-1, PAF-1-SO3Ag. IAST calculations using single-component-isotherm data and equimolar ethylene/ethane ratio at 296 K reveal PAF-1-SO3Ag shows exceptionally high ethylene/ethane adsorption selectivi-ty (Sads: 27 to 125), far surpassing benchmark zeolite and any other MOF reported in literature. This alongside excellent water/air stability, high ethylene uptake capacity, and mild regeneration requirements make PAF-1-SO3Ag hold promise for adsorption-based eth-ylene/ethane separations, paving a way to develop Ag(I) ion function-alized POPs as a new platform for highly selective adsorption of eth-ylene over ethane.

  9. Tuning the adsorption behaviors of water, methanol, and ethanol in a porous material by varying the flexibility of substituted groups.

    Science.gov (United States)

    Sha, Yunfei; Bai, Shizhe; Lou, Jiaying; Wu, Da; Liu, Baizhan; Ling, Yun

    2016-05-01

    Exploring the adsorption and separation of water, methanol, and ethanol is important concerning the use of a sustainable energy source from biofuel. In this paper, the effects of the flexibility of substituted groups have been studied based on three iso-reticular metal-organic frameworks (MOFs), in which the pore surface is decorated with propargyl (-CH2-C[triple bond, length as m-dash]CH), allyl (-CH2-CH[double bond, length as m-dash]CH2), and propyl (-CH2-CH2-CH3) groups respectively. These substituted groups stretch into the channel, acting as gates, and the gate-opening for guests is controlled by the flexibility as well as host-guest interactions. Our study results indicate that (i) the adsorption capacity of water, methanol and ethanol enhances accordingly with the increase of the flexibility of substituted groups; (ii) the adsorptive discrimination of water, methanol, and ethanol on this porous sorbent could be tuned by varying the substituted groups. PMID:27074997

  10. Synthesis and electrochemical capacitive properties of nitrogen-doped porous carbon micropolyhedra by direct carbonization of zeolitic imidazolate framework-11

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Fei; Li, Li; Zhang, Xiaohua, E-mail: mickyxie@hnu.edu.cn; Chen, Jinhua, E-mail: chenjinhua@hnu.edu.cn

    2015-06-15

    Highlights: • Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were prepared from ZIF-11. • The activated N-PCMPs with fused KOH (N-PCMPs-A) have high specific surface area. • N-PCMPs-A exhibits high specific capacitance. • N-PCMPs-A reveals good cycling performance even at a high current density. - Abstract: Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were successfully prepared by direct carbonization of ZIF-11 polyhedra and further activated with fused KOH to obtain N-PCMPs-A. The morphology and microstructure of samples were examined by scanning electron microscopy, X-ray diffraction, and micropore and chemisorption analyzer. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge/discharge method in 1.0 M H{sub 2}SO{sub 4} aqueous solution on a standard three-electrode system. Results show that, compared with N-PCMPs, N-PCMPs-A has higher specific surface area (2188 m{sup 2} g{sup −1}) and exhibits improved electrochemical capacitive properties (307 F g{sup −1} at 1.0 A g{sup −1}). The mass specific capacitance of N-PCMPs-A is also higher than that of most MOF-derived carbons, some carbide-derived carbons and carbon aerogel-derived carbons. In addition, the capacitance of the N-PCMPs-A retains 90% after 4000 cycles even at a high current density of 10 A g{sup −1}. These imply that N-PCMPs-A is the promising materials for the construction of a high-performance supercapacitor.

  11. Synthesis and electrochemical capacitive properties of nitrogen-doped porous carbon micropolyhedra by direct carbonization of zeolitic imidazolate framework-11

    International Nuclear Information System (INIS)

    Highlights: • Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were prepared from ZIF-11. • The activated N-PCMPs with fused KOH (N-PCMPs-A) have high specific surface area. • N-PCMPs-A exhibits high specific capacitance. • N-PCMPs-A reveals good cycling performance even at a high current density. - Abstract: Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were successfully prepared by direct carbonization of ZIF-11 polyhedra and further activated with fused KOH to obtain N-PCMPs-A. The morphology and microstructure of samples were examined by scanning electron microscopy, X-ray diffraction, and micropore and chemisorption analyzer. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge/discharge method in 1.0 M H2SO4 aqueous solution on a standard three-electrode system. Results show that, compared with N-PCMPs, N-PCMPs-A has higher specific surface area (2188 m2 g−1) and exhibits improved electrochemical capacitive properties (307 F g−1 at 1.0 A g−1). The mass specific capacitance of N-PCMPs-A is also higher than that of most MOF-derived carbons, some carbide-derived carbons and carbon aerogel-derived carbons. In addition, the capacitance of the N-PCMPs-A retains 90% after 4000 cycles even at a high current density of 10 A g−1. These imply that N-PCMPs-A is the promising materials for the construction of a high-performance supercapacitor

  12. Colloid migration in porous media

    International Nuclear Information System (INIS)

    Retention of radionuclides for long periods near waste repositories depends upon multiple barriers, one of which is adsorption to immobile solid surfaces. Since small particles and colloidal matter have high adsorption capacities per unit mass and can be mobile in subsurface flows, colloidal transport of waste components requires analysis. Theories for predicting colloid migration through porous media have been developed in the filtration literature. The applicability of filtration theories for predicting particle and colloid transport. Emphasis is on suspended matter much smaller than pore sizes, where physical and chemical forces control migration rather than size dependent physical straining. In general, experimentally verifiable theories exist for particle filtration by clean media, and a sensitivity analysis is possible on particle and media properties and fluid flow rate. When particle aggregates accumulate within pores, media permeability decreases, resulting in flow field alteration and possible radionuclide isolation. An analysis of the limited experimental data available indicates that present theories cannot predict long-term colloid transport when permeability reduction occurs. The coupling of colloid attachment processes and the hydrologic flow processes requires more extensive laboratory field research than has currently been carried out. An emphasis on the fundamental mechanisms is necessary to enhance long-term predictability

  13. Study of HKUST (Copper benzene-1,3,5-tricarboxylate, Cu-BTC MOF)-1 metal organic frameworks for CH4 adsorption: An experimental Investigation with GCMC (grand canonical Monte-carlo) simulation

    International Nuclear Information System (INIS)

    We have measured the methane uptakes on HKUST (Copper benzene-1,3,5-tricarboxylate, Cu-BTC MOF)-1 MOF (metal organic framework) for the temperatures ranging from 120 K to 300 K and pressures up to 10 bar. The experimentally measured HKUST-1 + CH4 isotherms data are compared with uptakes of various adsorbents and methane systems. We have also simulated the methane uptakes and its density distribution on HKUST-1 employing GCMC (grand canonical Monte-carlo) simulation and compare with experimental data. In this article, we also present an extensive study on characterization and property evaluation of HKUST-1 MOF for CH4 adsorption characteristics employing XRD (X-ray diffraction), SEM (scanning electron microscope) and TGA (thermo gravimetric analysis). Employing GCMC and the thermodynamic property fields of HKUST-1 + CH4 system, the isosteric heat of adsorption (Qst) is calculated and Qst is presented in a T-s (temperature-entropy) diagram. - Highlights: • Characterization of HKUST-1 MOFs by XRD, SEM, N2 adsorption and TGA. • Measurement of CH4 uptakes on HKUST-1 by volumetric methods. • GCMC simulation of methane uptakes and its density distribution on HKUST-1. • Isosteric heat of adsorption in a T-s (temperature-entropy) diagram

  14. From porous gold nanocups to porous nanospheres and solid particles - A new synthetic approach

    KAUST Repository

    Ihsan, Ayesha

    2015-05-01

    We report a versatile approach for the synthesis of porous gold nanocups, porous gold nanospheres and solid gold nanoparticles. Gold nanocups are formed by the slow reduction of gold salt (HAuCl4{dot operator}3H2O) using aminoantipyrene (AAP) as a reducing agent. Adding polyvinylpyrrolidone (PVP) to the gold salt followed by reduction with AAP resulted in the formation of porous gold nanospheres. Microwave irradiation of both of these porous gold particles resulted in the formation of slightly smaller but solid gold particles. All these nanoparticles are thoroughly characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and bright-field tomography. Due to the larger size, porous nature, low density and higher surface area, these nanomaterials may have interesting applications in catalysis, drug delivery, phototherapy and sensing.

  15. Porous silicon: Synthesis and optical properties

    International Nuclear Information System (INIS)

    Formation of porous silicon by electrochemical etching method of both p and n-type single crystal silicon wafers in HF based solutions has been performed by using three different modes. In addition to DC and pulsed voltage, a novel etching mode is developed to prepare light-emitting porous silicon by applying and holding-up a voltage in gradient steps form periodically, between the silicon wafer and a graphite electrode. Under same equivalent etching conditions, periodic gradient steps voltage etching can yield a porous silicon layer with stronger photoluminescence intensity and blue shift than the porous silicon layer prepared by DC or pulsed voltage etching. It has been found that the holding-up of the applied voltage during the etching process for defined interval of time is another significant future of this method, which highly affects the blue shift. This can be used for tailoring a porous layer with novel properties. The actual mechanism behind the blue shift is not clear exactly, even the experimental observation of atomic force microscope and purist measurements in support with quantum confinement model. It has been seen also from Fourier Transform Infrared study that interplays between O-Si-H and Si-H bond intensities play key role in deciding the efficiency of photoluminescence emission. Study of relative humidity sensing and photonic crystal properties of pours silicon samples has confirmed the advantages of the new adopted etching mode. The sensitivity at room temperature of porous silicon prepared by periodic gradient steps voltage etching was found to be about 70% as compared to 51% and 45% for the porous silicon prepared by DC and pulsed voltage etching, respectively. (author)

  16. Photoluminescence of porous silicon with liquid crystalline fillers

    International Nuclear Information System (INIS)

    Luminescence spectra of both pure porous silicon and filled with liquid crystals 5CB and H109 which emit radiation in violet spectral region are investigated. It is shown that there are bands of both porous silicon and a liquid crystal in the luminescence spectrum of porous silicon with liquid crystall filler. Thus the intensity of the band corresponding to porous silicon increases several times in comparison with a luminescence of pure porous silicon without filler. Experimental results are explained by internal no radiating swapping of energy from a liquid crystal to porous silicon

  17. MoF6在NaF颗粒上的吸附平衡及吸附动力学%Adsorption equilibrium and kinetics of molybdenum hexafluoride on sodium fluoride adsorbent

    Institute of Scientific and Technical Information of China (English)

    程治强; 李杨娟; 张国欣; 张焕琦; 李洒洒; 窦强; 龙德武; 吴国忠; 李晴暖

    2015-01-01

    为阐明六氟化钼(Molybdenum hexafluoride, MoF6)在氟化钠(Sodium fluoride, NaF)颗粒上的吸附机制,在静态吸附实验装置上研究了MoF6在NaF颗粒上的吸附平衡及吸附动力学行为,结果表明在50−100ºC内,NaF颗粒对MoF6的吸附速率和平衡吸附量随着温度而升高,在100ºC平衡吸附量达到115mg MoF6·g−1 NaF。当温度超过100ºC时,NaF对MoF6的吸附作用减弱,吸附量减小。Langmuir模型能较好描述NaF颗粒对MoF6的吸附过程,并推测MoF6在NaF颗粒上的吸附为单分子层吸附。吸附动力学模型分析表明,NaF颗粒对MoF6的吸附符合准二级动力学方程,同时吸附过程受到颗粒内扩散控制,但其并不是唯一速率控制步骤。%Background:The fluoride volatility processhas been developed to recover uranium from spent nuclear fuel. And the fluoride adsorption and desorption technique is usually applied to the purification of UF6 in the fluoride volatility process.Purpose: This study aims to investigate the adsorption mechanism of MoF6 on NaF adsorbent. Methods: The adsorption equilibrium and kinetics of MoF6 on NaF adsorbent at different temperatures and initial MoF6 pressure were experimentally studied by using statistic adsorption equipment. Langmuir adsorption model and adsorption kinetics model were applied to analyse experimental data.Results:The adsorption rate and equilibrium adsorption capacity of MoF6 on NaF adsorbent increased with the temperature increasing from 50 ºC to 100 ºC, and the adsorption capacity was 115 mg MoF6·g−1 NaF at 100 ºC.The experimental data were fitted by pseudo-second-order kinetics as well as Langmuir adsorption model.Conclusion:The adsorption of MoF6on NaF adsorbent was monolayer adsorption according to Langmuir adsorption model, and was controlled by diffusion of MoF6 inside NaF adsorbent which was not the unique rate-determining step, though.

  18. Mixed ligand two dimensional Cd(ii)/Ni(ii) metal organic frameworks containing dicarboxylate and tripodal N-donor ligands: Cd(ii) MOF is an efficient luminescent sensor for detection of picric acid in aqueous media.

    Science.gov (United States)

    Rachuri, Yadagiri; Parmar, Bhavesh; Bisht, Kamal Kumar; Suresh, Eringathodi

    2016-05-01

    Two dimensional metal organic frameworks (MOFs) [Cd(5-BrIP)(TIB)]n () and [Ni2(5-BrIP)2(TIB)2]n (), involving the aromatic polycarboxylate ligand 5-bromo isophthalic acid (H2BrIP), flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (TIB) and Cd(ii)/Ni(ii) metal nodes have been synthesized by different methods. These compounds were characterized by various analytical methods, and variable temperature X-ray diffraction data showed thermal stability of both MOFs up to 350 °C. Phase purity as well as water stability of the MOFs were established by powder X-ray diffraction, and the structural diversity of the compounds were investigated by single-crystal X-ray diffraction. Both the MOFs are mixed ligand 2D nets, and the topology of the network can be described as a binodal 3,5-c connected net with 3,5L2 topology having the point symbol {4(2)·6(7)·8}{4(2)·6}. Sensing of picric acid [2,4,6-trinitrophenol, TNP] by luminescence quenching among a large range of nitroanalytes in aqueous phase by the Cd(ii) luminescent MOF (LMOF) were been investigated. Structural studies on 1 : 1 co-crystals () of TIB and TNP were carried out. The selective and sensitive fluorescence quenching response of towards electron-deficient TNP over other nitro analytes in aqueous phase was demonstrated by fluorescence quenching titration. Concomitant occurrence of electron transfer/energy transfer processes and electrostatic interaction favours the selective sensing of TNP. A Cd(ii) LMOF ()-coated paper strip that we developed demonstrated fast and selective response to TNP, by the complete quenching of the blue fluorescence upon excitation of the paper strip at 365 nm radiation in its presence. PMID:27067118

  19. Combustion and heat transfer in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Sathe, S.B.; Peck, R.E.; Tong, T.W.

    1990-06-01

    The objective of the present study is to generate fundamental knowledge about heat transfer and combustion in porous radiant burners (PRBs) in order to improve their performance. A theoretical heat transfer and combustion model is developed to study the characteristics of PRBs. The model accounts for non-local thermal equilibrium between the solid and gas phases. The solid is assumed to absorb, emit and scatter radiant energy. Combustion is modeled as a one-step global reaction. It is revealed that the flame speed inside the porous medium is enhanced compared to the adiabatic flame speeds due to the higher conductivity of the solid compared to the gas as well as due to radiative preheating of the reactants. The effects of the properties of the porous material on the flame speeds, radiative outputs and efficiencies were investigated. To improve the radiative output from the burner, it is desirable that the porous layer has an optical thickness of about ten. The radiative output and the efficiency is higher for lower scattering albedo. The heat transfer coupling between the solid and gas phases should be high enough to ensure local thermal equilibrium, by choosing a fine porous matrix. Higher solid phase conduction enhances the flame speed and the radiative output. Experiments are performed on a ceramic foam to verify the theoretical findings. The existence of the two stability regions was verified experimentally.

  20. Exceptional gravimetric and volumetric CO2 uptake in a palladated NbO-type MOF utilizing cooperative acidic and basic, metal-CO2 interactions.

    Science.gov (United States)

    Spanopoulos, I; Bratsos, I; Tampaxis, C; Vourloumis, D; Klontzas, E; Froudakis, G E; Charalambopoulou, G; Steriotis, T A; Trikalitis, P N

    2016-08-18

    A novel NbO-type MOF is reported based on a palladated organic linker, showing a remarkable gravimetric and volumetric CO2 uptake, reaching 201.8 cm(3) g(-1) (9.0 mmol g(-1), 39.7 wt%) and 187.8 cm(3) cm(-3) at 273 K and 1 bar, respectively. Accurate theoretical calculations revealed that the exceptional CO2 uptake is due to the combination of Lewis base Pd(ii)-CO2 (24.3 kJ mol(-1)) and Lewis acid Cu(ii)-CO2 (30.3 kJ mol(-1)) interactions, as well as synergistic pore size effects. PMID:27498783

  1. Luminescence and Magnetic Properties of Two Three-Dimensional Terbium and Dysprosium MOFs Based on Azobenzene-4,4′-Dicarboxylic Linker

    Directory of Open Access Journals (Sweden)

    Belén Fernández

    2016-02-01

    Full Text Available We report the in situ formation of two novel metal-organic frameworks based on terbium and dysprosium ions using azobenzene-4,4′-dicarboxylic acid (H2abd as ligand, synthesized by soft hydrothermal routes. Both materials show isostructural three-dimensional networks with channels along a axis and display intense photoluminescence properties in the solid state at room temperature. Textural properties of the metal-organic frameworks (MOFs have been fully characterized although no appreciable porosity was obtained. Magnetic properties of these materials were studied, highlighting the dysprosium material displays slightly frequency-dependent out of phase signals when measured under zero external field and under an applied field of 1000 Oe.

  2. Ultrasonically assisted hydrothermal synthesis of activated carbon-HKUST-1-MOF hybrid for efficient simultaneous ultrasound-assisted removal of ternary organic dyes and antibacterial investigation: Taguchi optimization.

    Science.gov (United States)

    Azad, F Nasiri; Ghaedi, M; Dashtian, K; Hajati, S; Pezeshkpour, V

    2016-07-01

    Activated carbon (AC) composite with HKUST-1 metal organic framework (AC-HKUST-1 MOF) was prepared by ultrasonically assisted hydrothermal method and characterized by FTIR, SEM and XRD analysis and laterally was applied for the simultaneous ultrasound-assisted removal of crystal violet (CV), disulfine blue (DSB) and quinoline yellow (QY) dyes in their ternary solution. In addition, this material, was screened in vitro for their antibacterial actively against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) bacteria. In dyes removal process, the effects of important variables such as initial concentration of dyes, adsorbent mass, pH and sonication time on adsorption process optimized by Taguchi approach. Optimum values of 4, 0.02g, 4min, 10mgL(-1) were obtained for pH, AC-HKUST-1 MOF mass, sonication time and the concentration of each dye, respectively. At the optimized condition, the removal percentages of CV, DSB and QY were found to be 99.76%, 91.10%, and 90.75%, respectively, with desirability of 0.989. Kinetics of adsorption processes follow pseudo-second-order model. The Langmuir model as best method with high applicability for representation of experimental data, while maximum mono layer adsorption capacity for CV, DSB and QY on AC-HKUST-1 estimated to be 133.33, 129.87 and 65.37mgg(-1) which significantly were higher than HKUST-1 as sole material with Qm to equate 59.45, 57.14 and 38.80mgg(-1), respectively. PMID:26964963

  3. Characterizations of PSD Fractal of Porous Medium

    Institute of Scientific and Technical Information of China (English)

    黄国强; 徐世民; 李鑫钢

    2003-01-01

    A volume-based method for measuring particle-size distribution (PSD) fractal dimensions of porous mediums was developed by employing laser size-analyzing technology. Compared with conventional approaches of using hydrometer or screen to determine PSD, this method can avoid calculation errors and measure smaller size-scale porous medium. In this paper the experimental porous mediums were brown soil, kaolin and sand soil. A micro-order of magnitude (10-5 m) in particle-size interval could be shown in PSD results of brown soil and kaolin. The experiments indicated that brown soil had a nearly mono-fractal PSD character, while kaolin and sand soil showed multi-fractal PSD characters. By the adsorption isotherm experiments, the PSD fractal dimensions of the sand soil were also found to keep a linearly increasing relation with the linear adsorptive parameters of the soils in different intervals to adsorb benzene from aqueous solution.

  4. Porous ferroelectrics for energy harvesting applications

    Science.gov (United States)

    Roscow, J.; Zhang, Y.; Taylor, J.; Bowen, C. R.

    2015-11-01

    This paper provides an overview of energy harvesting using ferroelectric materials, with a particular focus on the energy harvesting capabilities of porous ferroelectric ceramics for both piezo- and pyroelectric harvesting. The benefits of introducing porosity into ferro- electrics such as lead zirconate titanate (PZT) has been known for over 30 years, but the potential advantages for energy harvesting from both ambient vibrations and temperature fluctuations have not been studied in depth. The article briefly discusses piezoelectric and pyro- electric energy harvesting, before evaluating the potential benefits of porous materials for increasing energy harvesting figures of merits and electromechanical/electrothermal coupling factors. Established processing routes are evaluated in terms of the final porous structure and the resulting effects on the electrical, thermal and mechanical properties.

  5. Synthesis of Emulsion-templated Porous Polycaprolactone

    Directory of Open Access Journals (Sweden)

    Xiao Chenchen

    2016-01-01

    Full Text Available Emulsion-templated porous materials have gained extensively in applications due to their low density and high porosity. However, by far most this type porous polymers are synthesized using conventional radical polymerization and most of the reactions are thermally initiated. Expanding the polymerization mechanisms available for emulsion-templated polymers synthesis is still highly desired. In this work, Diel-Alder (DA reaction was used to synthesize emulsion-templated macroporous polycaprolactone (PCL. These macroporous polymers were prepared by DA reaction of polycaprolactone pendant with multiple furan group (PCL-furan and 1,6-bis(maleimidehexane (BisM via a high internal 1phase emulsion as template. The porous materials have a typical structure of emulsion-templated 2materials.

  6. Fluid dynamics in porous media with Sailfish

    CERN Document Server

    Coelho, Rodrigo C V

    2016-01-01

    In this work we show the application of Sailfish to the study of fluid dynamics in porous media. Sailfish is an open-source software based on the lattice-Boltzmann method. This application of computational fluid dynamics is of particular interest to the oil and gas industry and the subject could be a starting point for an undergraduate or graduate student in physics or engineering. We built artificial samples of porous media with different porosities and used Sailfish to simulate the fluid flow through in order to calculate permeability and tortuosity. We also present a simple way to obtain the specific superficial area of porous media using Python libraries. To contextualize these concepts, we test the Kozeny--Carman equation, discuss its validity and calculate the Kozeny's constant for our artificial samples.

  7. Study of water radiolysis in porous media

    International Nuclear Information System (INIS)

    The understanding of the production of H2 in the radiolysis of water confined into pores of concrete is important for the disposal of radioactive waste. In order to describe the mechanisms of water radiolysis in such heterogeneous porous systems we have studied the behaviour under gamma radiation of water confined in porous silica glasses with pores going from 8 to 300 nm of diameter and meso-porous molecular sieves (MCM-41). The radiolytic yields of hydroxyl radicals, hydrated electron and dihydrogen, have been determined with respect to the pore size of materials. The increase of these radiolytic yields compared to those of free water allowed us to show a charge transfer from silica to confined water. On the other hand the kinetics of hydrated electron reactions measured by pulse radiolysis are not modified. (author)

  8. New permeameter for geologic porous-media

    International Nuclear Information System (INIS)

    The use of a modified microbore HPLC/SFC system is described as an automated rapid-analysis permeameter for studying the interactions of liquid hazardous-waste leachates with low permeability geologic porous-media(1). Numerous advantages over currently described equipment for permeability and leachate/soil compatibility testing are shown. The system can operate in a constant pressure mode for generating precise and constant hydraulic-gradients on porous media samples, or in a constant flow-rate and mode. Both techniques allow continuous real-time monitoring of permeability changes. The system can also determine when steady-state baseline hydraulic conductivity of the porous media has been achieved and then automatically switch permeants for chemical interaction studies. The instrument continuously monitors and displays permeant flow-rate, permeameter cell pressure-drop and UV-VIS absorbance of contaminant species in solution

  9. Trends in modeling of porous media combustion

    Energy Technology Data Exchange (ETDEWEB)

    Mujeebu, M. Abdul; Abdullah, M. Zulkifly [Porous Media Combustion Laboratory, School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Mohamad, A.A. [College of Engineering, Alfaisal University, Riyadh 11533, P.O. Box 50927 (Saudi Arabia); Bakar, M.Z. Abu [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

    2010-12-15

    Porous media combustion (PMC) has interesting advantages compared with free flame combustion due to higher burning rates, increased power dynamic range, extension of the lean flammability limits, and low emissions of pollutants. Extensive experimental and numerical works were carried out and are still underway, to explore the feasibility of this interesting technology for practical applications. For this purpose, numerical modeling plays a crucial role in the design and development of promising PMC systems. This article provides an exhaustive review of the fundamental aspects and emerging trends in numerical modeling of gas combustion in porous media. The modeling works published to date are reviewed, classified according to their objectives and presented with general conclusions. Numerical modeling of liquid fuel combustion in porous media is excluded. (author)

  10. Investigation of heat transfer in porous duct

    Science.gov (United States)

    Athani, Abdulgaphur; Khan, T. M. Yunus

    2016-05-01

    Investigation of heat transfer in a square porous duct is carried out. The porous medium is sandwiched between inner and outer surface of a square duct. The flow is assumed to follow the Darcy law. The governing momentum and energy equations are non-dimensionalised and then converted to algebraic form of equations using finite element method. Galerkin method is used to transform the partial differential equations into simpler algebraic equations then solved in a iterative manner to arrive at the solution. The results are presented with respect to various geometric and physical parameters such as depth of porous medium, Rayleigh number etc. It is found that the isotherms and the streamlines take symmetrical position along the vertical central line of square duct. The isotherms are penetrated into deeper area at upper half of duct as compared to lower half.

  11. Gas foamed open porous biodegradable polymeric microspheres.

    Science.gov (United States)

    Kim, Taek Kyoung; Yoon, Jun Jin; Lee, Doo Sung; Park, Tae Gwan

    2006-01-01

    Highly open porous biodegradable polymeric microspheres were fabricated for use as injectable scaffold microcarriers for cell delivery. A modified water-in-oil-in-water (W1/O/W2) double emulsion solvent evaporation method was employed for producing the microspheres. The incorporation of an effervescent salt, ammonium bicarbonate, in the primary W1 droplets spontaneously produced carbon dioxide and ammonia gas bubbles during the solvent evaporation process, which not only stabilized the primary emulsion, but also created well inter-connected pores in the resultant microspheres. The porous microspheres fabricated under various gas foaming conditions were characterized. The surface pores became as large as 20 microm in diameter with increasing the concentration of ammonium bicarbonate, being sufficient enough for cell infiltration and seeding. These porous scaffold microspheres could be potentially utilized for cultivating cells in a suspension manner and for delivering the seeded cells to the tissue defect site in an injectable manner. PMID:16023197

  12. Fluid dynamics in porous media with Sailfish

    Science.gov (United States)

    Coelho, Rodrigo C. V.; Neumann, Rodrigo F.

    2016-09-01

    In this work we show the application of Sailfish to the study of fluid dynamics in porous media. Sailfish is an open-source software based on the lattice-Boltzmann method. This application of computational fluid dynamics is of particular interest to the oil and gas industry and the subject could be a starting point for an undergraduate or graduate student in physics or engineering. We built artificial samples of porous media with different porosities and used Sailfish to simulate the fluid flow through them in order to calculate their permeability and tortuosity. We also present a simple way to obtain the specific superficial area of porous media using Python libraries. To contextualise these concepts, we analyse the applicability of the Kozeny–Carman equation, which is a well-known permeability–porosity relation, to our artificial samples.

  13. POROUS PAVEMENT. PHASE I. DESIGN AND OPERATIONAL CRITERIA

    Science.gov (United States)

    Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

  14. Explosion propagation in inert porous media.

    Science.gov (United States)

    Ciccarelli, G

    2012-02-13

    Porous media are often used in flame arresters because of the high surface area to volume ratio that is required for flame quenching. However, if the flame is not quenched, the flow obstruction within the porous media can promote explosion escalation, which is a well-known phenomenon in obstacle-laden channels. There are many parallels between explosion propagation through porous media and obstacle-laden channels. In both cases, the obstructions play a duel role. On the one hand, the obstruction enhances explosion propagation through an early shear-driven turbulence production mechanism and then later by shock-flame interactions that occur from lead shock reflections. On the other hand, the presence of an obstruction can suppress explosion propagation through momentum and heat losses, which both impede the unburned gas flow and extract energy from the expanding combustion products. In obstacle-laden channels, there are well-defined propagation regimes that are easily distinguished by abrupt changes in velocity. In porous media, the propagation regimes are not as distinguishable. In porous media the entire flamefront is affected, and the effects of heat loss, turbulence and compressibility are smoothly blended over most of the propagation velocity range. At low subsonic propagation speeds, heat loss to the porous media dominates, whereas at higher supersonic speeds turbulence and compressibility are important. This blending of the important phenomena results in no clear transition in propagation mechanism that is characterized by an abrupt change in propagation velocity. This is especially true for propagation velocities above the speed of sound where many experiments performed with fuel-air mixtures show a smooth increase in the propagation velocity with mixture reactivity up to the theoretical detonation wave velocity. PMID:22213663

  15. Porous structure formation in ion irradiated germanium

    International Nuclear Information System (INIS)

    The ion beam induced modification of amorphous germanium is characterised by the formation of voids close to the sample surface and the transformation into a sponge-like porous surface layer at high ion fluences. This extreme structural modification of the sample surface is independent of the (heavy) ion species used and accompanied by a strong volume expansion. Nevertheless, recently it was demonstrated that buried voids (and buried sponge-like layers) can be formed in the depth of the projected ion range, however, only for the irradiation with I-ions at high ion fluences. Thus, the ion species and their chemical properties seem to play an important role in the structural modification around the projected ion range. In this paper we investigate the influence of the ion species on the ion beam induced void formation in Ge for room temperature irradiation with 380 keV I- and Au-ions as a function of the ion fluence. Independent of the ion species, a strong volume expansion is observed caused by void formation and the transformation into a sponge-like porous surface layer. For both ion species used, the final porous layers are structurally identical as established by cross section and plan view electron microscopy investigations. Further ion irradiation of the sponge-like porous structure, however, leads to significant differences in the ion beam induced structural evolution. For the Au-ion irradiation the porous layer remains nearly unchanged, whereas for the irradiation with I-ions a transformation from sponge-like to netlike porous layers occurs which is accompanied again by an extreme volume expansion. The underlying mechanism will be discussed based on chemical properties of the implanted ions

  16. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2007-01-01

    The intrinsic size-effect for porous metals is investigated. The analyses are carried out numerically using a finite strain generalization of a higher order strain gradient plasticity model. Results for plane strain growth of cylindrical voids are presented in terms of response curves and curves of...... material. For porous materials with small void volume fractions under highly triaxial tension, void growth is analysed through cavitation instabilities using a finite element Rayleigh–Ritz procedure. Cavitation instabilities are found to be delayed for small voids, so that higher stress levels are needed...

  17. Mixed convection opposing flow in porous annulus

    Science.gov (United States)

    Salman, Ahmed N. J.; Kamangar, Sarfaraz; Al-Rashed, Abdullah A. A. A.; Khan, T. M. Yunus; Khaleed, H. M. T.

    2016-06-01

    The current work investigates the mixed convection flow in a vertical porous annulus embedded with fluid saturated porous medium. The annulus is isothermally heated discretely at 20%, 35% and 50% of the height of cylinder at the center of annulus. Darcy law with thermal non-equilibrium approach is considered. The governing partial differential equations are solved using Finite Element Method (FEM). The effects of Peclet number Pe and conductivity ratio Kr on heat transfer and fluid flow is discussed It is found that the applied velocity in the downward direction, in case of an opposing flow, does not allow the thermal energy to reach from a hot to a cold surface.

  18. Heat transfers in porous media. Phase changes

    International Nuclear Information System (INIS)

    Phase change phenomena in porous media, like all poly-phase processes, are complex and still only partially understood. This article deals only with the liquid-vapor phase change (vaporization-condensation) because of its particular practical importance in numerous domains. Content: 1 - Fixing of a fluid constituent inside a porous matrix; 2 - mathematical modeling; 3 - example of reference situations: phase changes at temperatures below the saturation temperature (vaporization, condensation), phase changes at temperatures above the saturation temperature (condensation, vaporization-boiling); 4 - conclusion. (J.S.)

  19. On physical equation of porous material

    International Nuclear Information System (INIS)

    The authors offer simple-to-use physical equations of porous body in the framework of the associated law of flow. The equations meet the conditions of cylindrical type flow known in the theory of porous body plasticity. The equations offered are compared with the physical equations meeting the conditions of elliptical type flow. They were applied in modeling the process of press titanium sponge. Together with the physical equations offered, the mathematical tools and the experimental procedure to model the processes of pressing the non-compacted raw material blanks are proposed too

  20. Measurement of Emissivity of Porous Ceramic Materials

    OpenAIRE

    BÜYÜKALACA, Orhan

    1998-01-01

    In this study, measurements of spectral and total emissivities of seven different porous ceramic materials and one ceramic fibre material are reported. Measurements were made for wavelength range from 1.2 µm to 20 µm and temperature range from 200 °C to 700 °C. It was found that total emissivity increases with increase of pore size but decreases with increase of temperature. The results showed all the porous ceramic materials tested to be much better than ceramic fibre in terms of total em...

  1. Additive Manufacturing of Hierarchical Porous Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grote, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division. Polymers and Coatings

    2016-08-30

    Additive manufacturing has become a tool of choice for the development of customizable components. Developments in this technology have led to a powerful array of printers that t serve a variety of needs. However, resin development plays a crucial role in leading the technology forward. This paper addresses the development and application of printing hierarchical porous structures. Beginning with the development of a porous scaffold, which can be functionalized with a variety of materials, and concluding with customized resins for metal, ceramic, and carbon structures.

  2. Impact dynamics of porous powder. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Titov, V.M.

    1995-12-31

    The shock adiabats have been built experimentally in the range of moderate pressures for three porous materials: Al{sub 2}O{sub 3} wheat flour, and their mixture. The model, which describes the behavior of porous powder materials under large-amplitude dynamic loading, has been constructed. The model applicability to describing the shock wave processes is confirmed by good agreement of the calculated shock adiabats and the data obtained in the experiments. The compressive strength of compacted samples has been determined. The possible trend of further researches is presented in conclusion. 15 refs., 19 figs., 6 tabs.

  3. Superhydrophobicity on nanostructured porous hydrophilic material

    Science.gov (United States)

    Jiang, Hong-Ren; Chan, Deng-Chi

    2016-04-01

    By applying laser oxidation, ablation, and plasma treatment to modify a surface of polydimethylsiloxane, we show that creating hydrophobic sites on an originally superhydrophilic nanostructured porous surface greatly changes the wetting properties of the surface. The modified surface may even become superhydrophobic while the ratio of added hydrophobic site to the surface is relatively low. The relation between the contact angles and the effect of hydrophobic sites is further tested in blade scraping method and a similar result is also obtained. This method to achieve superhydrophobicity on the hydrophilic nanostructured porous material may open possibilities for achieving superhydrophobicity and enable functional superhydrophobic surfaces with heterogeneous components.

  4. Porous ceramic scaffolds with complex architectures

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, Eduardo; Munch, Etienne; Franco, Jaime; Deville, Sylvain; Hunger, Phillip; Saiz, Eduardo; Tomsia, Antoni P.

    2008-03-15

    This work compares two novel techniques for the fabrication of ceramic scaffolds for bone tissue engineering with complex porosity: robocasting and freeze casting. Both techniques are based on the preparation of concentrated ceramic suspensions with suitable properties for the process. In robocasting, the computer-guided deposition of the suspensions is used to build porous materials with designed three dimensional (3-D) geometries and microstructures. Freeze casting uses ice crystals as a template to form porous lamellar ceramic materials. Preliminary results on the compressive strengths of the materials are also reported.

  5. Making Porous Luminescent Regions In Silicon Wafers

    Science.gov (United States)

    Fathauer, Robert W.; Jones, Eric W.

    1994-01-01

    Regions damaged by ion implantation stain-etched. Porous regions within single-crystal silicon wafers fabricated by straightforward stain-etching process. Regions exhibit visible photoluminescence at room temperature and might constitute basis of novel class of optoelectronic devices. Stain-etching process has advantages over recently investigated anodic-etching process. Process works on both n-doped and p-doped silicon wafers. Related development reported in article, "Porous Si(x)Ge(1-x) Layers Within Single Crystals of Si," (NPO-18836).

  6. Novel hybrid multifunctional magnetoelectric porous composite films

    Science.gov (United States)

    Martins, P.; Gonçalves, R.; Lopes, A. C.; Venkata Ramana, E.; Mendiratta, S. K.; Lanceros-Mendez, S.

    2015-12-01

    Novel multifunctional porous films have been developed by the integration of magnetic CoFe2O4 (CFO) nanoparticles into poly(vinylidene fluoride)-Trifuoroethylene (P(VDF-TrFE)), taking advantage of the synergies of the magnetostrictive filler and the piezoelectric polymer. The porous films show a piezoelectric response with an effective d33 coefficient of -22 pC/N-1, a maximum magnetization of 12 emu g-1 and a maximum magnetoelectric coefficient of 9 mV cm-1 Oe-1. In this way, a multifunctional membrane has been developed suitable for advanced applications ranging from biomedical to water treatment.

  7. Quasi-Porous Plug With Vortex Chamber

    Science.gov (United States)

    Walsh, J. V.

    1985-01-01

    Pressure-letdown valve combines quasi-porous-plug and vortex-chamber in one controllable unit. Valve useful in fossil-energy plants for reducing pressures in such erosive two-phase process streams as steam/water, coal slurries, or combustion gases with entrained particles. Quasi-Porous Plug consists of plenums separated by perforated plates. Number or size of perforations increases with each succeeding stage to compensate for expansion. In Vortex Chamber, control flow varies to control swirl and therefore difference between inlet and outlet pressures.

  8. Porous media fluid transport and pore structure

    CERN Document Server

    Dullien, F A L

    1992-01-01

    This book examines the relationship between transport properties and pore structure of porous material. Models of pore structure are presented with a discussion of how such models can be used to predict the transport properties of porous media. Portions of the book are devoted to interpretations of experimental results in this area and directions for future research. Practical applications are given where applicable, and are expected to be useful for a large number of different fields, including reservoir engineering, geology, hydrogeology, soil science, chemical process engineering, biomedica

  9. Review on Fractal Analysis of Porous Metal Materials

    OpenAIRE

    Wang, J. Z.; J. MA; Ao, Q. B.; H. Zhi; Tang, H. P.

    2015-01-01

    Porous metal materials are multifunctional lightweight materials and have been used widely in industry. The structural and functional characters of porous metal materials depend on the pore structure which can be described effectively by the fractal theory. This paper reviews the major achievements on fractal analysis of pore structure of porous metal materials made by State Key Laboratory of Porous Metal Materials, China, over the past few years. These include (i) designing and developing a ...

  10. Stabilization of a highly porous metal-organic framework utilizing a carborane-based linker.

    Science.gov (United States)

    Clingerman, Daniel J; Morris, William; Mondloch, Joseph E; Kennedy, Robert D; Sarjeant, Amy A; Stern, Charlotte; Hupp, Joseph T; Farha, Omar K; Mirkin, Chad A

    2015-04-18

    The first tritopic carborane-based linker, H3BCA (C15B24O6H30), based on closo-1,10-C2B8H10, has been synthesized and incorporated into a metal-organic framework (MOF), NU-700 (Cu3(BCA)2). In contrast to the analogous MOF-143, NU-700 can be activated with retention of porosity, yielding a BET surface area of 1870 m(2) g(-1). PMID:25767827

  11. Computational study of porous materials for gas separations

    Science.gov (United States)

    Lin, Li-Chiang

    Nanoporous materials such as zeolites, zeolitic imidazolate frameworks (ZIFs), and metal-organic frameworks (MOFs) are used as sorbents or membranes for gas separations such as carbon dioxide capture, methane capture, paraffin/olefin separations, etc. The total number of nanoporous materials is large; by changing the chemical composition and/or the structural topologies we can envision an infinite number of possible materials. In practice one can synthesize and fully characterize only a small subset of these materials. Hence, computational study can play an important role by utilizing various techniques in molecular simulations as well as quantum chemical calculations to accelerate the search for optimal materials for various energy-related separations. Accordingly, several large-scale computational screenings of over one hundred thousand materials have been performed to find the best materials for carbon capture, methane capture, and ethane/ethene separation. These large-scale screenings identified a number of promising materials for different applications. Moreover, the analysis of these screening studies yielded insights into those molecular characteristics of a material that contribute to an optimal performance for a given application. These insights provided useful guidelines for future structural design and synthesis. For instance, one of the screening studies indicated that some zeolite structures can potentially reduce the energy penalty imposed on a coal-fired power plant by as much as 35% compared to the near-term MEA technology for carbon capture application. These optimal structures have topologies with a maximized density of pockets and they capture and release CO2 molecules with an optimal energy. These screening studies also pointed to some systems, for which conventional force fields were unable to make sufficiently reliable predictions of the adsorption isotherms of different gasses, e.g., CO2 in MOFs with open-metal sites. For these systems, we

  12. Microfluidic devices and methods including porous polymer monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

    2015-12-01

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  13. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  14. Zein Recovery Using Non-Porous Membranes

    Science.gov (United States)

    Mairal, Anurag P.; Ng, Alvin; Wijmans, Johannes G.

    2005-01-25

    A membrane process for treating zein solutions to increase the zein concentration in the solution. The process uses a non-porous membrane that preferentially permeates the solvent and rejects the zein. Optionally, the process can be operated as a diafiltration process to yield a concentrate of high zein purity.

  15. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice

    2015-10-07

    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  16. Layer like porous materials with hierarchical structure

    Czech Academy of Sciences Publication Activity Database

    Roth, W. J.; Gil, B.; Makowski, W.; Marszalek, B.; Eliášová, Pavla

    -, - (2016). ISSN 0306-0012 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : porous materials * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 33.383, year: 2014

  17. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

  18. Refractive index contrast in porous silicon multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Nava, R.; Mora, M.B. de la; Tagueena-Martinez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Rio, J.A. del [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Centro Morelense de Innovacion y Transferencia Tecnologica, Consejo de Ciencia y Tecnologia del Estado de Morelos (Mexico)

    2009-07-15

    Two of the most important properties of a porous silicon multilayer for photonic applications are flat interfaces and a relative large refractive index contrast between layers in the optical wavelength range. In this work, we studied the effect of the current density and HF electrolyte concentration on the refractive index of porous silicon. With the purpose of increasing the refractive index contrast in a multilayer, the refractive index of porous silicon produced at low current was studied in detail. The current density applied to produce the low porosity layers was limited in order to keep the electrolyte flow through the multilayer structure and to avoid deformation of layer interfaces. We found that an electrolyte composed of hydrofluoric acid, ethanol and glycerin in a ratio of 3:7:1 gives a refractive index contrast around 1.3/2.8 at 600 nm. Several multilayer structures with this refractive index contrast were fabricated, such as dielectric Bragg mirrors and microcavities. Reflectance spectra of the structures show the photonic quality of porous silicon multilayers produced under these electrochemical conditions. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. A porous SiC ammonia sensor

    NARCIS (Netherlands)

    Connolly, E.J.; Timmer, B.H.; Pham, H.T.M.; Groeneweg, J.; Sarro, P.M.; Olthuis, W.; French, P.J.

    2005-01-01

    When used as the dielectric in a capacitive sensing arrangement, porous SiC has been found to be extremely sensitive to the presence of ammonia (NH3) gas. The exact sensing method is still not clear, but NH3 levels as low as 0.5 ppm could be detected. We report the fabrication and preliminary charac

  20. Theory of porous media - past and present

    Energy Technology Data Exchange (ETDEWEB)

    Boer, R. de [Essen Univ. (Germany). Inst. fuer Mechanik

    1998-10-01

    Porous solids filled with liquid or gas play an important role in engineering, e.g., in material science, petroleum industry, chemical engineering, and soil mechanics as well as in biomechanics. Although porous media are of considerable practical significance the description of their mechanical and thermodynamical behavior has been unsatisfactory for a long time. The theory to describe the complex thermodynamical behavior of such saturated porous solids has come to certain well-founded conclusions only recently. It is the goal of this paper to show the historical development of the porous media theory, which already started in the eighteenth century, formed in some areas by polemic disputes and tragic events in the lifes of the scientists involved. Furthermore, the current state of the research into this subject is discussed, whereby the state of the development of the material independent basic equations and the constitutive theory is illustrated. For a certain class of models general theorems, such as minimum and maximum problems, are derived and the uniqueness of solutions of boundary value problems is proved. (orig.)

  1. Porous bead packings for gas chromatography

    Science.gov (United States)

    Pollock, G. E.; Woeller, F. H.

    1979-01-01

    Porous polyaromatic packing beads have low polarity, high efficiency, short retention time, and may be synthesized in size range of 50 to 150 micrometers (100 to 270 mesh). Mechanically strong beads may be produced using various materials depending on elements and compounds to be identified.

  2. MECHANICAL STRENGTH OF HIGHLY POROUS CERAMICS

    NARCIS (Netherlands)

    VANDENBORN, IC; SANTEN, A; HOEKSTRA, HD; DEHOSSON, JTM; Born, I.C. van den

    1991-01-01

    This paper reports on the mechanical strength of highly porous ceramics in terms of the Weibull and Duxbury-Leath distributions. More than 1000 side-crushing strength tests on silica-catalyst carriers of various particle sizes have been performed in series. Within a series, preparation conditions we

  3. Chaotic Mixing in Three Dimensional Porous Media

    CERN Document Server

    Lester, Daniel R; Borgne, Tanguy Le

    2016-01-01

    Under steady flow conditions, the topological complexity inherent to all random 3D porous media imparts complicated flow and transport dynamics. It has been established that this complexity generates persistent chaotic advection via a three-dimensional (3D) fluid mechanical analogue of the baker's map which rapidly accelerates scalar mixing in the presence of molecular di?usion. Hence pore-scale fluid mixing is governed by the interplay between chaotic advection, molecular di?usion and the broad (power-law) distribution of fluid particle travel times which arise from the non-slip condition at pore walls. To understand and quantify mixing in 3D porous media, we consider these processes in a model 3D open porous network and develop a novel stretching continuous time random walk (CTRW) which provides analytic estimates of pore-scale mixing which compare well with direct numerical simulations. We ?nd that chaotic advection inherent to 3D porous media imparts scalar mixing which scales exponentially with longitudi...

  4. Porous Silicon—A Versatile Host Material

    Directory of Open Access Journals (Sweden)

    Klemens Rumpf

    2010-02-01

    Full Text Available This work reviews the use of porous silicon (PS as a nanomaterial which is extensively investigated and utilized for various applications, e.g., in the fields of optics, sensor technology and biomedicine. Furthermore the combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Such nanocompounds offer a broad avenue of new and interesting properties depending on the kind of involved materials as well as on their morphology. The filling of the pores performed by electroless or electrochemical deposition is described, whereas different morphologies, reaching from micro- to macro pores are utilized as host material which can be self-organized or fabricated by prestructuring. For metal-deposition within the porous structures, both ferromagnetic and non-magnetic metals are used. Emphasis will be put on self-arranged mesoporous silicon, offering a quasi-regular pore arrangement, employed as template for filling with ferromagnetic metals. By varying the deposition parameters the precipitation of the metal structures within the pores can be tuned in geometry and spatial distribution leading to samples with desired magnetic properties. The correlation between morphology and magnetic behaviour of such semiconducting/magnetic systems will be determined. Porous silicon and its combination with a variety of filling materials leads to nanocomposites with specific physical properties caused by the nanometric size and give rise to a multiplicity of potential applications in spintronics, magnetic and magneto-optic devices, nutritional food additives as well as drug delivery.

  5. Thermal and optical properties of porous silicon

    Directory of Open Access Journals (Sweden)

    Silva A. Ferreira da

    2001-01-01

    Full Text Available Thermal diffusivity and optical absorption have been investigated for porous silicon, at room temperature, using photoacoustic spectroscopy. The experimental results obtained conform well with the existing studies recently published. The value obtained for thermal diffusivity is 0.045 ± 0.002 cm²/s.The absorption onsets show energy structures, differing from the ordinary semiconductor of bulk type.

  6. Structure of random porous materials: Silica aerogel

    International Nuclear Information System (INIS)

    Using small-angle x-ray scattering, we show that porous silica aerogel has a fractal backbone structure. The observed structure is traced to the underlying chemical (polymerization) and physical (colloid aggregation) growth processes. Comparison of scattering curves for aerogel with silica aggregates confirms this interpretation

  7. Tracer transfer in consolidated porous medium and fractured porous medium: experimentations and modelling

    International Nuclear Information System (INIS)

    We try to identify and model physical and chemical mechanisms governing the water flow and the solute transport in fractured consolidated porous medium. An original experimental device was built. The 'cube' consists of an idealized fractured medium reproduced by piling up consolidated porous cubes of 5 cm edge. Meanwhile, columns of the homogeneous consolidated porous medium are studied. The same anionic tracing technique is used in both cases. Using a system analysis approach, we inject concentration pulses in the device to obtain breakthrough curves. After identifying the mass balance and the residence time, we fit the CD and the MIM models to the experimental data. The MIM model is able to reproduce experimental curves of the homogeneous consolidated porous medium better than the CD model. The mobile water fraction is in accordance with the porous medium geometry. The study of the flow rate influence highlights an interference dispersion regime. It was not possible to highlight the observation length influence in this case. On the contrary, we highlight the effect of the observation scale on the fractured and porous medium, comparing the results obtained on a small 'cube' and a big 'cube'. The CD model is not satisfactory in this case. Even if the MIM model can fit the experimental breakthrough curves, it was not possible to obtain unique parameters for the set of experiments. (author)

  8. Force modulation microscopy of multilayered porous silicon samples

    Science.gov (United States)

    Sbrana, F.; Ghulinyan, M.; Pavesi, L.

    2005-06-01

    In this paper we report on Force Modulation Microscopy (FMM) study and force-distance curve analysis of porous silicon layers grown on silicon. The characterization has been carried out on the cross section of porous silicon. The FMM images allowed us to investigate the morphological thickness of the layers through local elasticity differences resolving both between porous silicon layers of different porosities and between porous silicon and silicon itself. Force-distance curves showed different adhesion behaviour: porous silicon is more hydrophobic than bulk silicon in cross sectional view.

  9. Fluid flow and heat transfer in rotating porous media

    CERN Document Server

    Vadasz, Peter

    2016-01-01

    This Book concentrates the available knowledge on rotating fluid flow and heat transfer in porous media in one single reference. Dr. Vadasz develops the fundamental theory of rotating flow and heat transfer in porous media and introduces systematic classification and identification of the relevant problems. An initial distinction between rotating flows in isothermal heterogeneous porous systems and natural convection in homogeneous non-­‐isothermal porous systems provides the two major classes of problems to be considered. A few examples of solutions to selected problems are presented, highlighting the significant impact of rotation on the flow in porous media.

  10. Equilibrium and transfer in porous media 2 transfer laws

    CERN Document Server

    Daïan, Jean-François

    2014-01-01

    A porous medium is composed of a solid matrix and its geometrical complement: the pore space. This pore space can be occupied by one or more fluids. The understanding of transport phenomena in porous media is a challenging intellectual task.  This book provides a detailed analysis of the aspects required for the understanding of many experimental techniques in the field of porous media transport phenomena. It is aimed at studentsor engineers who may not be looking specifically to become theoreticians in porous media, but wish to integrate knowledge of porous media with their previous scientif

  11. Porous solid backbone impregnation for electrochemical energy conversion systems

    KAUST Repository

    Boulfrad, Samir

    2013-09-19

    An apparatus and method for impregnating a porous solid backbone. The apparatus may include a platform for holding a porous solid backbone, an ink jet nozzle configured to dispense a liquid solution onto the porous solid backbone, a positioning mechanism configured to position the ink jet nozzle proximate to a plurality of locations of the porous solid backbone, and a control unit configured to control the positioning mechanism to position the ink jet nozzle proximate to the plurality of locations and cause the ink jet nozzle to dispense the liquid solution onto the porous solid backbone.

  12. Hydrogen storage by physisorption on porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Panella, B.

    2006-09-13

    A great challenge for commercializing hydrogen powered vehicles is on-board hydrogen storage using economic and secure systems. A possible solution is hydrogen storage in light-weight solid materials. Here three principle storage mechanisms can be distinguished: i) absorption of hydrogen in metals ii) formation of compounds with ionic character, like complex hydrides and iii) physisorption (or physical adsorption) of hydrogen molecules on porous materials. Physical adsorption exhibits several advantages over chemical hydrogen storage as for example the complete reversibility and the fast kinetics. Two classes of porous materials were investigated for physical hydrogen storage, i.e. different carbon nanostructures and crystalline metal-organic frameworks possessing extremely high specific surface area. Hydrogen adsorption isotherms were measured using a Sieverts' apparatus both at room temperature and at 77 K at pressures up to the saturation regime. Additionally, the adsorption sites of hydrogen in these porous materials were identified using thermal desorption spectroscopy extended to very low temperatures (down to 20 K). Furthermore, the adsorbed hydrogen phase was studied in various materials using Raman spectroscopy at different pressures and temperatures. The results show that the maximum hydrogen storage capacity of porous materials correlates linearly with the specific surface area and is independent of structure and composition. In addition the pore structure of the adsorbent plays an important role for hydrogen storage since the adsorption sites for H2 could be assigned to pores possessing different dimensions. Accordingly it was shown that small pores are necessary to reach high storage capacities already at low pressures. This new understanding may help to tailor and optimize new porous materials for hydrogen storage. (orig.)

  13. Combustion synthesis of porous titanium microspheres

    International Nuclear Information System (INIS)

    The synthesis of titanium porous microspheres by a combustion technique was studied under an argon atmosphere by using a TiO2 − 2.5Mg reactive mixture. The precursor, a fine TiO2 powder, was thermally treated in the range 600–1300 °C prior to the combustion experiments. TiO2 microspheres whose diameters were between 10 and 50 μm were obtained from precursor particles annealed in the range 900–1100 °C. A biphase product consisting of Ti and MgO phases was obtained when the TiO2 microspheres were reduced with Mg. The spherical morphology of the final particles was retained despite the relatively high combustion temperatures (1630–1670 °C) used in this study. Moreover, porous titanium microspheres were obtained when the MgO particles were dissolved using acid leaching. Scanning electron microscopy (SEM) images of the microspheres suggested that the spherical structure contained ∼0.5–2.0-μm-diameter porous windows. The Brunauer–Emmett–Teller (BET) surface area of the Ti microspheres was determined to be 2.8 m2 g−1. - Highlights: • TiO2 + 2.5Mg mixture was combusted under argon pressure to produce titanium microspheres. • Microspheres with a porous framework structure were obtained at 1630–1670 °C. • The microspheres exhibited 10–50 μm average diameters with porous window of ∼0.5–2.0 μm and BET surface area of 2.8 m2 g−1. - Graphical abstract: Display Omitted

  14. Morphology and transmittance of porous alumina on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo Peitao, E-mail: guopeitao@hotmail.com [Wuhan University of Technology. Wuhan (China); Xia Zhilin [Wuhan University of Technology. Wuhan (China); Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan (China); Xue Yiyu [Wuhan University of Technology. Wuhan (China); Huang Caihua [China Three Gorges University, Yichang (China); Zhao Lixin [Wuhan University of Technology. Wuhan (China)

    2011-02-01

    The porous optical film has higher threshold of laser-induced damage than densified films, for the study of mechanism of laser-induced damage of porous optical film with ordered pore structure. Porous anodic alumina (PAA) film with high transmittance on glass substrate has been prepared. Aluminum film was deposited on glass substrate by means of resistance and electron beam heat (EBH) evaporation. Porous alumina was prepared in oxalic acid solution under different anodizing conditions. At normal incidence, the optical transmittance spectrum over 300-1000 nm spectra region was obtained by spectrophotometer. SEM was introduced to analysis the morphology of the porous alumina film. The pore aperture increased with the increase of anodizing voltage, which resulted in a rapid decrease of the pore concentration and the optical thickness of porous alumina film. Damage morphology of porous alumina film is found to be typically defects initiated, and the defect is the pore presented on the film.

  15. Method of fabricating porous silicon carbide (SiC)

    Science.gov (United States)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1995-01-01

    Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

  16. Increasing the CO2 /N2 Selectivity with a Higher Surface Density of Pyridinic Lewis Basic Sites in Porous Carbon Derived from a Pyridyl-Ligand-Based Metal-Organic Framework.

    Science.gov (United States)

    Li, Liangjun; Wang, Ying; Gu, Xin; Yang, Qipeng; Zhao, Xuebo

    2016-07-01

    The development of functional porous carbon with high CO2 /N2 selectivity is of great importance for CO2 capture. In this paper, a type of porous carbon with doped pyridinic sites (termed MOFC) was prepared from the carbonization of a pyridyl-ligand based MOF. Four MOFCs derived from different carbonizing temperatures were prepared. Structural studies revealed high contents of pyridinic-N groups and nearly the same pore-size distributions for these MOFCs. Gas-sorption studies revealed outstanding CO2 uptake at low pressures and room temperature. Owing to the high content of pyridinic-N groups, the CO2 /N2 selectivity on these MOFCs exhibits values of about 40-50, which are among the top values in carbon materials. Further correlation studies demonstrated that the CO2 /N2 selectivities show a positive linear relationship with the surface density of pyridinic-N groups, thus validating the synergistic effect of the doped pyridinic-N groups on CO2 adsorption selectivity. PMID:27146096

  17. Synthesis of MOF having hydroxyl functional side groups and optimization of activation process for the maximization of its BET surface area

    International Nuclear Information System (INIS)

    To accomplish the postsynthetic modification of MOF with organic-metal precursors (OMPs) described in our previous researches more efficiently, synthesis of MOF (HCC-2) possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit than those of HCC-1 has been successfully conducted via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO3)2·6H2O as a metal source, respectively. Also, optimization about the Activation process of HCC-2 was performed to maximize its BET (Brunauer–Emmett–Teller) surface area which was proved to be proportional to the number of exposed active sites on which its postsynthetic modification occurred. However, Activation process having been validated to be so effective with the acquirement of highly-purified HCC-1 (CO2 supercritical drying step followed by vacuum drying step) was less satisfactory with the case of HCC-2. This might be attributed to relatively higher hydrophilicity and bulkier molecular structure of organic ligand of HCC-2. However, it was readily settled by simple modification of above Activation process. Moreover, indispensable residues composed of both DMF and its thermally degraded derivatives which were chemically attached via coordination bond with hydroxyl functionalities even after Activation process III might enable their H2 adsorption properties to be seriously debased compared to that of IRMOF-16 having no hydroxyl functionalities. - Graphical abstract: Synthesis of new-structured MOF (HCC-2) simultaneously possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit at the same time than those of HCC-1 has been performed via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO3)2·6H2O as a metal source, respectively. Also, the optimization of activation process for HCC-2 was conducted to maximize its BET surface area while the

  18. The formation of the Baptistina family by catastrophic disruption: Porous versus non-porous parent body

    Science.gov (United States)

    Jutzi, M.; Michel, P.; Benz, W.; Richardson, D. C.

    2009-01-01

    In this paper, we present numerical simulations aimed at reproducing the Baptistina family based on its properties estimated by observations. A previous study by Bottke et al. (2007) indicated that this family is probably at the origin of the K/T impactor, is linked to the CM meteorites and was produced by the disruption of a parent body 170 km in size due to the head-on impact of a projectile 60 km in size at 3 km s-1. This estimate was based on simulations of fragmentation of non-porous materials, while the family was assumed to be of C taxonomic type, which is generally interpreted as being formed from a porous body. Using both a model of fragmentation of non-porous materials, and a model that we developed recently for porous ones, we performed numerical simulations of disruptions aimed at reproducing this family and at analyzing the differences in the outcome between those two models. Our results show that a reasonable match to the estimated size distribution of the real family is produced from the disruption of a porous parent body by the head-on impact of a projectile 54 km in size at 3 km s-1. Thus, our simulations with a model consistent with the assumed dark type of the family requires a smaller projectile than previously estimated, but the difference remains small enough to not affect the proposed scenario of this family history. We then find that the break-up of a porous body leads to different outcomes than the disruption of a non-porous one. The real properties of the Baptistina family still contain large uncertainties, and it remains possible that its formation did not involve the proposed impact conditions. However, the simulations presented here already show some range of outcomes and once the real properties are better constrained, it will be easy to check whether one of them provides a good match.

  19. Hydrogen bonding and coordination bonding in the electronically excited states of the MOF Cu2 (L)2 (L=5-(4-pyridyl)tetrazole) CH2Cl2: A time-dependent density functional theory study

    International Nuclear Information System (INIS)

    The solvent-dependent luminescent metal-organic framework (MOF), Cu2(L)2·CH2Cl2 (L=5-(4-pyridyl)tetrazole), in the electronically excited states was studied using time-dependent density functional theory (TDDFT) method. Based on the analysis of the frontier molecular orbitals and electronic configuration, it revealed that the emission is attributed to a ligand-to-metal charge transfer (LMCT). Besides, we investigated the behavior of the hydrogen bonding and coordination bonding in the excited state S1 of Cu2(L)2·CH2Cl2. The results indicated that the strength of the hydrogen bonding N5⋯H39-C2 between the dichloromethane molecule and the tetrazole ligand was decreased in the S1 state, while the coordination bond Cu2-N8 was strengthened in the excited state. Moreover, we further demonstrated that the hydrogen bonding weakening and coordination bonding strengthening should be beneficial to the luminescent process of the MOF. Highlights: ► Solvent-dependent luminescent MOF was studied by TDDFT. ► Emission mechanism was a ligand to metal charge transition (LMCT). ► 1H NMR and binding energies indicate H-bond weakening in excited states. ► The coordination bonds become stronger in the excited states

  20. Cage-Type Highly Graphitic Porous Carbon-Co3O4 Polyhedron as the Cathode of Lithium-Oxygen Batteries.

    Science.gov (United States)

    Tang, Jing; Wu, Shichao; Wang, Tao; Gong, Hao; Zhang, Huabin; Alshehri, Saad M; Ahamad, Tansir; Zhou, Haoshen; Yamauchi, Yusuke

    2016-02-01

    A novel cage-type highly graphitic porous carbon-Co3O4 (GPC-Co3O4) polyhedron was designed and successfully prepared for the first time by executing a two-step annealing of core-shell structured metal-organic frameworks (MOFs). The low graphitic carbon cores were selectively removed during the secondary annealing in air atmospheres, leaving the interior voids due to their lower thermal stability compared with the graphitic carbon shells. Inspired by the unique properties of the cage-type GPC-Co3O4 polyhedron, GPC-Co3O4 was assembled as an oxygen electrode for a rechargeable Li-O2 battery without the additional conductive agent. The efficient generation of Li2O2 during discharging and the reversible decomposition of Li2O2 during charging were clearly observed by XRD patterns and SEM images. The GPC-Co3O4 polyhedron integrates the beneficial properties, including high electronic conductivity, the rigid cage-type structure consisting of the mesoporous walls and interior void space, as well as the uniformly embedded catalytically active Co3O4 nanoparticles. As a result, the GPC-Co3O4 cathode displays a low charge overpotential of 0.58 V, a good rate capability, and a long cycle life in a Li-O2 battery. PMID:26788868

  1. Uniaxial deformation of a soft porous material

    Science.gov (United States)

    MacMinn, Chris; Dufresne, Eric; Wettlaufer, John

    2015-11-01

    Compressing a porous material will decrease the volume of pore space, driving fluid out. Similarly, injecting fluid into a porous material will drive mechanical deformation, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with linear elasticity and then further linearizing in the strain. This is a good model for very small deformations, but it becomes increasingly inappropriate as deformations grow larger, and moderate to large deformations are common in the context of phenomena such as swelling, damage, and extreme softness. Here, we compare the predictions of linear poroelasticity with those of a rigorous large-deformation framework in the context of two uniaxial model problems. We explore the error associated with the linear model in both steady and dynamic situations, as well as the impact of allowing the permeability to vary with the deformation.

  2. Porous media: Analysis, reconstruction and percolation

    DEFF Research Database (Denmark)

    Rogon, Thomas Alexander

    1995-01-01

    Spatial structure of selected porous media has been analysed in terms of the two first spatial moments (i.e. porosity and autocorrelation). Having established directional isotropy in the three spatial planes, multiple geometrical features measured in 2-d are attempted generalized to 3-d using...... in binary fields. Percolation threshold of reconstructed porous media has been determined for different discretizations of a selected model correlation function. Also critical exponents such as the correlation length exponent v, the strength of the infinite network and the mean size of finite...... clusters have been determined. We have obtained results which indicate that the effect of spatial correlation does affect not only the percolation threshold but also the exponents with respect to the values known for random media. We have attempted to predict key percolation values for a continuous medium...

  3. Ultimate permeation across atomically thin porous graphene.

    Science.gov (United States)

    Celebi, Kemal; Buchheim, Jakob; Wyss, Roman M; Droudian, Amirhossein; Gasser, Patrick; Shorubalko, Ivan; Kye, Jeong-Il; Lee, Changho; Park, Hyung Gyu

    2014-04-18

    A two-dimensional (2D) porous layer can make an ideal membrane for separation of chemical mixtures because its infinitesimal thickness promises ultimate permeation. Graphene--with great mechanical strength, chemical stability, and inherent impermeability--offers a unique 2D system with which to realize this membrane and study the mass transport, if perforated precisely. We report highly efficient mass transfer across physically perforated double-layer graphene, having up to a few million pores with narrowly distributed diameters between less than 10 nanometers and 1 micrometer. The measured transport rates are in agreement with predictions of 2D transport theories. Attributed to its atomic thicknesses, these porous graphene membranes show permeances of gas, liquid, and water vapor far in excess of those shown by finite-thickness membranes, highlighting the ultimate permeation these 2D membranes can provide. PMID:24744372

  4. Porous Organic Cages for Sulfur Hexafluoride Separation.

    Science.gov (United States)

    Hasell, Tom; Miklitz, Marcin; Stephenson, Andrew; Little, Marc A; Chong, Samantha Y; Clowes, Rob; Chen, Linjiang; Holden, Daniel; Tribello, Gareth A; Jelfs, Kim E; Cooper, Andrew I

    2016-02-10

    A series of porous organic cages is examined for the selective adsorption of sulfur hexafluoride (SF6) over nitrogen. Despite lacking any metal sites, a porous cage, CC3, shows the highest SF6/N2 selectivity reported for any material at ambient temperature and pressure, which translates to real separations in a gas breakthrough column. The SF6 uptake of these materials is considerably higher than would be expected from the static pore structures. The location of SF6 within these materials is elucidated by X-ray crystallography, and it is shown that cooperative diffusion and structural rearrangements in these molecular crystals can rationalize their superior SF6/N2 selectivity. PMID:26757885

  5. Unreacted Hugoniots for porous and liquid explosives

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, R.L.; Sheffield, S.A.

    1993-08-01

    Numerous authors have measured the Hugoniots of a variety of granular explosives pressed to different densities. Each explosive at each density was typically then treated as a unique material having its own Hugoniot. By combining methods used by Hayes, Sheffield and Mitchell (for describing the Hugoniot of HNS at various densities) with Hermann`s P-{alpha} model, it is only necessary to know some thermodynamic constants or the Hugoniot of the initially solid material and the porous material sound speed to obtain accurate unreacted Hugoniots for the porous explosive. We discuss application of this method to several materials including HMX, PETN, TNT, and Tetryl, as well as HNS. We also show that the ``Universal Liquid Hugoniot`` can be used to calculate the unreacted Hugoniot for liquid explosives. With this method only the ambient pressure sound speed and density are needed to predict the Hugoniot. Applications presented include nitromethane and liquid TNT.

  6. Simulation of penetration into porous geologic media

    Energy Technology Data Exchange (ETDEWEB)

    Vorobiev, O Y; Liu, B T; Lomov, I N; Antoun, T

    2005-05-31

    We present a computational study on the penetration of steel projectiles into porous geologic materials. The purpose of the study is to extend the range of applicability of a recently developed constitutive model to simulations involving projectile penetration into geologic media. The constitutive model is non-linear, thermodynamically consistent, and properly invariant under superposed rigid body motions. The equations are valid for large deformations and they are hyperelastic in the sense that the stress tensor is related to a derivative of the Helmholtz free energy. The model uses the mathematical structure of plasticity theory to capture the basic features of the mechanical response of geological materials including the effects of bulking, yielding, damage, porous compaction and loading rate on the material response. The new constitutive model has been successfully used to simulate static laboratory tests under a wide range of triaxial loading conditions, and dynamic spherical wave propagation tests in both dry and saturated geologic media.

  7. Large deformations of a soft porous material

    CERN Document Server

    MacMinn, Christopher W; Wettlaufer, John S

    2015-01-01

    Compressing a porous material will decrease the volume of pore space, driving fluid out. Similarly, injecting fluid into a porous material can drive mechanical deformation, distorting the solid skeleton. This poromechanical coupling has applications ranging from cell and tissue mechanics to geomechanics and hydrogeology. The classical theory of linear poroelasticity captures this coupling by combining Darcy's law with linear elasticity and then further linearizing in the strain. This is a good model for very small deformations, but it becomes increasingly inappropriate as deformations grow larger, and moderate to large deformations are common in the context of phenomena such as swelling or damage, or for materials that are extremely soft. Here, we first review a rigorous Eulerian framework for large-deformation poromechanics. We then compare the predictions of linear poroelasticity with those of fully nonlinear poromechanics in the context of two uniaxial model problems: Fluid outflow driven by an applied mec...

  8. Osmosis, filtration and fracture of porous media

    International Nuclear Information System (INIS)

    Filtration was produced in a small scale physical model of a granular porous medium of cylindrical shape.The same volume flow was obtained either applying a difference in hydrostatic pressure or in osmotic pressure.In the first case a process of sustained erosion ending in an hydraulic short circuit was observed,while in the second case the material remained stable.This paradoxical strength behaviour is explained using some results from differential geometry,classical field theory and thermo-kinetic theory.The fracture process of a continuous matrix in a porous medium under the combined effect of filtration and external mechanical loads in then considered.The obtained results can be applied to the textural and compressive strength of wet concrete

  9. Porous silicon bandgap broadening at natural oxidation

    International Nuclear Information System (INIS)

    Emission and excitation photoluminescence spectra of porous silicon thin layers have been investigated at natural oxidation. The shift of both types of spectra to high-energy region with time has been shown. Analysis of excitation spectra points out the indirect behavior of electron transitions responsible for visible photoluminescence, which remains unaltered at natural oxidation. The value of optical bandgap is estimated in each case. It is shown that the optical bandgap broadens during oxidation due to size reduction of silicon nanocrystallites. - Highlights: → Porous silicon emission and excitation spectra blue shifted at natural oxidation. → Excitation spectra points out the indirect behavior of electron transitions. → Optical bandgap broadens during oxidation due to Si nanoparticles size reduction.

  10. Luminescence kinetics of porous silicon: fluctuation approach

    CERN Document Server

    Bondarev, V N

    2001-01-01

    Theoretical interpretation of the kinetics of the photoluminescence (PL), caused by the tunnel radiative recombination of the photoexcited electron and hole, localized on the crystallite/matrix interface, is given on the basis of the notions on the porous silicon structure as an incidental totality of the Si nanodimensional crystallites, submerged into the SiO sub 2 matrix. The relatively slow (by the stretched exponential type) time drop in the PL intensity is the results of averaging the intensity in each PL elementary act by the electron and hole mutual disposition and by the crystallite dimensions. The good quantitative description of the low-temperature experiments may be obtained through the proposed approach both by the PL kinetics and time evolution of the porous silicon PL spectrum

  11. Integrating Porous Resins In Enzymatic Processes

    DEFF Research Database (Denmark)

    Al-Haque, Naweed

    enzymes to be harnessed. Porous resins as opposed to other auxiliary phases, for example organic solvents, are nonbioavailable, biocompatible and offer simpler operational handling (no foaming and emulsification). This strategy has been applied effectively to single substrate – single product systems...... screening procedure. The screening therefore becomes a multi-objective task that has to be solved simultaneously. Such an approach has been applied in the method formulated in this framework. To overcome these challenges, different process strategies are required to obtain high yields. A number of different...... challenges and proposed solutions are discussed in chapter one of this thesis and have also been published as a review. In recent years, integrating porous resins as an auxiliary phase in enzymatic processes, to non-selectively bind the substrate and product as a means to alleviate substrate and product...

  12. Investigation of drug-porous adsorbent interactions in drug mixtures with selected porous adsorbents.

    Science.gov (United States)

    Madieh, Shadi; Simone, Michael; Wilson, Wendy; Mehra, Dev; Augsburger, Larry

    2007-04-01

    The adsorption of drugs onto porous substrates may prove to be a convenient method by which to enhance the dissolution rate of certain poorly water-soluble drugs in body fluids. The purpose of this research is to provide a better understanding of the type of interactions occurring between drugs and certain pharmaceutically acceptable porous adsorbents that leads to enhanced drug dissolution rates. The interactions between ibuprofen (acidic drug), acetaminophen (acidic drug), dipyridamole (basic drug), and the porous adsorbents used (calcium silicate and silica gel) were investigated using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform infrared spectroscopy (FTIR). DSC and PXRD results indicated a significant loss of crystallinity of both ibuprofen and acetaminophen but not dipyridamole. In the case of ibuprofen, FTIR results indicated the ionization of the carboxylic group based on the shift in the FTIR carboxylic band. Dissolution of ibuprofen from its mixtures with porous adsorbents was found to be significantly higher compared to the neat drug, whereas dipyridamole dissolution from its mixtures with porous adsorbents was not significantly different from that of the neat drug. PMID:17221849

  13. Magnetic Fluid Flows in Porous Media

    Institute of Scientific and Technical Information of China (English)

    LI Ming-Jun; CHEN Liang

    2011-01-01

    @@ The seepage law under a magnetic field is obtained by up-scaling the flow at the pore scale of rigid porous media,and the macroscopic equivalent model is also obtained.It is proved that the macroscopic mass flow depends on the macroscopic magnetic force and the gradients of pressure and of magnetic pressure, as Zahn and Rosensweig have described in their experiments.The permeability tensor is symmetric and positive.

  14. Extending the Lifespan of Porous Asphalt Concrete

    OpenAIRE

    Zhang, Y.

    2015-01-01

    Porous Asphalt (PA) concrete is widely used as a surfacing layer on highways in the Netherlands. The service life of PA wearing courses is limited because of the fact that it is vulnerable to raveling. The possibilities of applying preventive maintenance to PA wearing courses by means of spraying rejuvenation products on the pavement surfaces are being investigated with high interest in the Netherlands. A material which has the ability to penetrate into the bituminous binder and soften (rejuv...

  15. Methane storage in porous activated carbons

    OpenAIRE

    Perl, András; Gemert, Wim van

    2014-01-01

    Locally produced methane, - either as biomethane or power-to-gas product, has to be stored to provide a reliable gas source for the fluctuating demand of any local gas distribution network. Additionally, methane is a prominent transportation fuel but its suitability for vehicular application depends on the ability to store an adequate amount in the onboard fuel tank. Adsorption in porous materials could enable a simple, safe and cost-effective method for storing methane at ambient temperature...

  16. Low temperature synthesis of porous silicate ceramics

    Directory of Open Access Journals (Sweden)

    Méndez Enríquez Y.

    2007-01-01

    Full Text Available Impregnation of a polyurethane sponge with kaolin, feldspar, silica, fusible glass slurry followed by temperature treatment in air in the temperature range 800-1000 0 C leads to the formation of aluminosilicate ceramics with a set pore size. The low-temperature synthesis of porous ceramics is based on the stage-by-stage formation of low-temperature eutectics and thermodestruction of polyurethane sponge.

  17. Novel lattice models for porous media

    OpenAIRE

    Andrey P Jivkov, Joseph E Olele

    2011-01-01

    Several barriers in a nuclear waste repository, such as waste immobilisers, backfills and host rock are porous. Predicting the changes in their permeability over the repository lifetime is critical to the assessment of radionuclide transport. Pore network models used in petrology offer an advantageous way for such predictions, because they can be linked elegantly to physical mechanisms that could lead to pore structure changes, e.g. mechanical damage, gas generation, or irradiation. The ex...

  18. Increased Functionality Porous Optical Fiber Structures

    OpenAIRE

    Wooddell, Michael Gary

    2007-01-01

    A novel fiber optic structure, termed stochastic ordered hole fibers, has been developed that contains an ordered array of six hollow tubes surrounding a hollow core, combined with a nanoporous glass creating a unique fully three dimensional pore/fiber configuration. The objective of this study is to increase the functionality of these stochastic ordered hole fibers, as well as porous clad fibers, by integrating electronic device components such as conductors, and semiconductor...

  19. Porous hydroxyapatite for artificial bone applications

    OpenAIRE

    I. Sopyan et al

    2007-01-01

    Hydroxyapatite (HA) has been used clinically for many years. It has good biocompatibility in bone contact as its chemical composition is similar to that of bone material. Porous HA ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Its high surfa...

  20. Migration of radionuclides in porous media

    International Nuclear Information System (INIS)

    One- and three-dimensional solutions based on the classical advection-dispersion equation have been developed and classified for the analysis of radionuclide transport in unconsolidated porous materials. The one-dimensional solutions have been applied for interpretation of experimental data obtained from radio-tracer tests with laboratory and field columns whereas both types of solutions were employed for interpretation of the field tracer test data