18 research outputs found
Enumerasi Total Populasi Mikroba Tanah Gambut Di Teluk Meranti Kabupaten Riau
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
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 = 4,4ā²-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 MetalāOrganic Frameworks with Acrylate Links
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 metalāorganic 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(āCO<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>ā3</sup> at 80 bar and 298 K, a value rivaling
that of HKUST-1 (200 cm<sup>3</sup> cm<sup>ā3</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 MetalāOrganic Framework-808
Superacids,
defined as acids with a Hammett acidity function <i>H</i><sub>0</sub> ā¤ ā12, are useful materials,
but a need exists for new, designable solid state systems. Here, we
report superacidity in a sulfated metalāorganic 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¤ ā14.5 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 MetalāOrganic Frameworks
The high porosity of metalāorganic 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>ā2</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 MetalāOrganic Frameworks and Related Materials
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 metalāorganic frameworks (MOFs). Among the MOFs are
10 zirconiumĀ(IV) MOFs with a subset of these, MOF-801-SC (single crystal
form), ā802, ā805, ā806, ā808, ā812,
and ā841 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>(āCO<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
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 4,4ā²-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
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 4,4ā²-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
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 4,4ā²-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