18 research outputs found

    Enumerasi Total Populasi Mikroba Tanah Gambut Di Teluk Meranti Kabupaten Riau

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    Teluk Meranti is one of the peatland area in Riau province. Most of these lands have beenchanged into palm oil plantation, timber plantation, agricultural area and settlement. Theaim of this research was to analyze the impact of land use changes on soil physical-chemical characteristics and microbial cell number. Soil samples were taken from eightdifferent locations, namely primary forest as control, secondary forest, rubber plantation(15 monthsyears old), rubber forest (40-60 years old), palm oil plantation (7-8 years old),acacia plantation (2-3 years old), corn field, and cassava field. Microbial cell number wasdetermined by spread plate method, employing appropriate media for the growth ofbacteria, fungi and actinomycetes. The results showed that the soil humidity, soiltemperature, percentage of soil dry weight, water content, soil bulk density and pH rangedfrom 29,63-55,88%, 27-31,5 o C, 14,9-35,5%, 64,9-85,1%, 0,16-0,39 g/cm 3 and 3,63-4,00,respectively. The copiotrophic bacterial cell number ranged from 0,6x10 5 -1,8x10 5 CFU/gsoil where the highest population was at the palm oil plantation,whereas the oligotrophicbacterial cell number ranged from 0,5x10 5 -1,4x10 5 CFU/g soil where the highest populationwas at the palm oil plantation. The population of fungi ranged from 0,4x10 5 -1,0x10 5 CFU/gsoil where the highest population was at the corn field. The population of actinomycetesranged from 0,4x10 5 -10,7x10 5 CFU/g soil where the highest population was at the palm oilplantation. Land use changes caused microbial cell number increased. The results indicatedthat land use changes influenced the microbial cell numbers

    From Nonporous to Porous Doubly-Pillared-Layer Framework: Control over Interpenetration via Shape Alteration of Layer Apertures

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    By introducing an amino substituent group on the dicarboxylate ligand, a porous doubly pillared-layer framework [Co<sub>2</sub>(abdc)<sub>2</sub>(bpy)<sub>2</sub>]Ā·8DMF (<b>2</b>; abdc = 2-amino-1,4-benzene dicarboxylate, bpy = 4,4ā€²-bipyridine) has been obtained, which represents a shape/size modulation of the layer apertures to control over 2-fold interpenetration arising from the nonporous structure of [Co<sub>2</sub>(bdc)<sub>2</sub>(bpy)<sub>2</sub>] (<b>1</b>; bdc = 1,4-benzene dicarboxylate). The bulk-phase purity, framework robustness and permanent porosity of <b>2</b> have been confirmed by powder X-ray diffraction, thermogravimetric analysis, and gas adsorption isotherms

    High Methane Storage Working Capacity in Metalā€“Organic Frameworks with Acrylate Links

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    High methane storage capacity in porous materials is important for the design and manufacture of vehicles powered by natural gas. Here, we report the synthesis, crystal structures and methane adsorption properties of five new zinc metalā€“organic frameworks (MOFs), MOF-905, MOF-905-Me<sub>2</sub>, MOF-905-Naph, MOF-905-NO<sub>2</sub>, and MOF-950. All these MOFs consist of the Zn<sub>4</sub>OĀ­(āˆ’CO<sub>2</sub>)<sub>6</sub> secondary building units (SBUs) and benzene-1,3,5-tri-Ī²-acrylate, BTAC. The permanent porosity of all five materials was confirmed, and their methane adsorption measured up to 80 bar to reveal that MOF-905 is among the best performing methane storage materials with a volumetric working capacity (desorption at 5 bar) of 203 cm<sup>3</sup> cm<sup>ā€“3</sup> at 80 bar and 298 K, a value rivaling that of HKUST-1 (200 cm<sup>3</sup> cm<sup>ā€“3</sup>), the benchmark compound for methane storage in MOFs. This study expands the scope of MOF materials with ultrahigh working capacity to include linkers having the common acrylate connectivity

    Superacidity in Sulfated Metalā€“Organic Framework-808

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    Superacids, defined as acids with a Hammett acidity function <i>H</i><sub>0</sub> ā‰¤ āˆ’12, are useful materials, but a need exists for new, designable solid state systems. Here, we report superacidity in a sulfated metalā€“organic framework (MOF) obtained by treating the microcrystalline form of MOF-808 [MOF-808-P: Zr<sub>6</sub>O<sub>5</sub>Ā­(OH)<sub>3</sub>Ā­(BTC)<sub>2</sub>Ā­(HCOO)<sub>5</sub>(H<sub>2</sub>O)<sub>2</sub>, BTC = 1,3,5-benzeneĀ­tricarĀ­boxĀ­ylate] with aqueous sulfuric acid to generate its sulfated analogue, MOF-808-2.5SO<sub>4</sub> [Zr<sub>6</sub>O<sub>5</sub>Ā­(OH)<sub>3</sub>Ā­(BTC)<sub>2</sub>Ā­(SO<sub>4</sub>)<sub>2.5</sub>(H<sub>2</sub>O)<sub>2.5</sub>]. This material has a Hammett acidity function <i>H</i><sub>0</sub> ā‰¤ āˆ’14.5 and is thus identified as a superacid, providing the first evidence for superacidity in MOFs. The superacidity is attributed to the presence of zirconium-bound sulfate groups structurally characterized using single-crystal X-ray diffraction analysis

    Supercapacitors of Nanocrystalline Metalā€“Organic Frameworks

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    The high porosity of metalā€“organic frameworks (MOFs) has been used to achieve exceptional gas adsorptive properties but as yet remains largely unexplored for electrochemical energy storage devices. This study shows that MOFs made as nanocrystals (nMOFs) can be doped with graphene and successfully incorporated into devices to function as supercapacitors. A series of 23 different nMOFs with multiple organic functionalities and metal ions, differing pore sizes and shapes, discrete and infinite metal oxide backbones, large and small nanocrystals, and a variety of structure types have been prepared and examined. Several members of this series give high capacitance; in particular, a zirconium MOF exhibits exceptionally high capacitance. It has the stack and areal capacitance of 0.64 and 5.09 mF cm<sup>ā€“2</sup>, about 6 times that of the supercapacitors made from the benchmark commercial activated carbon materials and a performance that is preserved over at least 10000 charge/discharge cycles

    Water Adsorption in Porous Metalā€“Organic Frameworks and Related Materials

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    Water adsorption in porous materials is important for many applications such as dehumidification, thermal batteries, and delivery of drinking water in remote areas. In this study, we have identified three criteria for achieving high performing porous materials for water adsorption. These criteria deal with condensation pressure of water in the pores, uptake capacity, and recyclability and water stability of the material. In search of an excellently performing porous material, we have studied and compared the water adsorption properties of 23 materials, 20 of which are metalā€“organic frameworks (MOFs). Among the MOFs are 10 zirconiumĀ­(IV) MOFs with a subset of these, MOF-801-SC (single crystal form), āˆ’802, āˆ’805, āˆ’806, āˆ’808, āˆ’812, and āˆ’841 reported for the first time. MOF-801-P (microcrystalline powder form) was reported earlier and studied here for its water adsorption properties. MOF-812 was only made and structurally characterized but not examined for water adsorption because it is a byproduct of MOF-841 synthesis. All the new zirconium MOFs are made from the Zr<sub>6</sub>O<sub>4</sub>(OH)<sub>4</sub>(āˆ’CO<sub>2</sub>)<sub><i>n</i></sub> secondary building units (<i>n</i> = 6, 8, 10, or 12) and variously shaped carboxyl organic linkers to make extended porous frameworks. The permanent porosity of all 23 materials was confirmed and their water adsorption measured to reveal that MOF-801-P and MOF-841 are the highest performers based on the three criteria stated above; they are water stable, do not lose capacity after five adsorption/desorption cycles, and are easily regenerated at room temperature. An X-ray single-crystal study and a powder neutron diffraction study reveal the position of the water adsorption sites in MOF-801 and highlight the importance of the intermolecular interaction between adsorbed water molecules within the pores

    Single-Crystal Structure of a Covalent Organic Framework

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    The crystal structure of a new covalent organic framework, termed COF-320, is determined by single-crystal 3D electron diffraction using the rotation electron diffraction (RED) method for data collection. The COF crystals are prepared by an imine condensation of tetra-(4-anilyl)Ā­methane and 4,4ā€²-biphenyldialdehyde in 1,4-dioxane at 120 Ā°C to produce a highly porous 9-fold interwoven diamond net. COF-320 exhibits permanent porosity with a Langmuir surface area of 2400 m<sup>2</sup>/g and a methane total uptake of 15.0 wt % (176 cm<sup>3</sup>/cm<sup>3</sup>) at 25 Ā°C and 80 bar. The successful determination of the structure of COF-320 directly from single-crystal samples is an important advance in the development of COF chemistry

    Single-Crystal Structure of a Covalent Organic Framework

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    The crystal structure of a new covalent organic framework, termed COF-320, is determined by single-crystal 3D electron diffraction using the rotation electron diffraction (RED) method for data collection. The COF crystals are prepared by an imine condensation of tetra-(4-anilyl)Ā­methane and 4,4ā€²-biphenyldialdehyde in 1,4-dioxane at 120 Ā°C to produce a highly porous 9-fold interwoven diamond net. COF-320 exhibits permanent porosity with a Langmuir surface area of 2400 m<sup>2</sup>/g and a methane total uptake of 15.0 wt % (176 cm<sup>3</sup>/cm<sup>3</sup>) at 25 Ā°C and 80 bar. The successful determination of the structure of COF-320 directly from single-crystal samples is an important advance in the development of COF chemistry

    Single-Crystal Structure of a Covalent Organic Framework

    No full text
    The crystal structure of a new covalent organic framework, termed COF-320, is determined by single-crystal 3D electron diffraction using the rotation electron diffraction (RED) method for data collection. The COF crystals are prepared by an imine condensation of tetra-(4-anilyl)Ā­methane and 4,4ā€²-biphenyldialdehyde in 1,4-dioxane at 120 Ā°C to produce a highly porous 9-fold interwoven diamond net. COF-320 exhibits permanent porosity with a Langmuir surface area of 2400 m<sup>2</sup>/g and a methane total uptake of 15.0 wt % (176 cm<sup>3</sup>/cm<sup>3</sup>) at 25 Ā°C and 80 bar. The successful determination of the structure of COF-320 directly from single-crystal samples is an important advance in the development of COF chemistry
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