scholarly journals How Reproducible Are Surface Areas Calculated from the BET Equation?

2021 ◽  
Author(s):  
Johannes Osterrieth ◽  
James Rampersad ◽  
David G. Madden ◽  
Nakul Rampal ◽  
Luka Skoric ◽  
...  
Keyword(s):  
Materials Science ◽  
Nanoporous Materials ◽  
Surface Areas ◽  
Wide Range ◽  
Bet Method ◽  
Metal Organic ◽  
Synthetic Zeolites ◽  
Bet Theory ◽  
First Time ◽  
Manual Calculation

Porosity and surface area analysis play a prominent role in modern materials science, where 123 their determination spans the fields of natural sciences, engineering, geology and medical 124 research. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory,[1] which has been 125 a remarkably successful contribution to the field of materials science. The BET method was 126 developed in the 1930s and is now the most widely used metric for the estimation of surface 127 areas of porous materials.[2] Since the BET method was first developed, there has been an 128 explosion in the field of nanoporous materials with the discovery of synthetic zeolites,[3] 129 nanostructured silicas,[4–6] metal-organic frameworks (MOFs),[7] and others. Despite its 130 widespread use, the manual calculation of BET surface areas causes a significant spread in 131 reported areas, resulting in reproducibility problems in both academia and industry. To probe 132 this, we have brought together 60 labs with strong track records in the study of nanoporous 133 materials. We provided eighteen adsorption isotherms and asked these researchers to 134 calculate the corresponding BET areas, resulting in a wide range of values for each one. We 135 show here that the reproducibility of BET area determination from identical isotherms is a 136 largely ignored issue, raising critical concerns over the reliability of reported BET areas in 137 the literature. To solve this major issue, we have developed a new computational approach 138 to accurately and systematically determine the BET area of nanoporous materials. Our 139 software, called BET Surface Identification (BETSI), expands on the well-known Rouquerol 140 criteria and makes, for the first time, an unambiguous BET area assignment possible.

scholarly journals How Reproducible Are Surface Areas Calculated from the BET Equation?

2021 ◽  
Author(s):  
Johannes Osterrieth ◽  
James Rampersad ◽  
David G. Madden ◽  
Nakul Rampal ◽  
Luka Skoric ◽  
...  
Keyword(s):  
Materials Science ◽  
Nanoporous Materials ◽  
Surface Areas ◽  
Wide Range ◽  
Bet Method ◽  
Metal Organic ◽  
Synthetic Zeolites ◽  
Bet Theory ◽  
First Time ◽  
Manual Calculation

Porosity and surface area analysis play a prominent role in modern materials science, where 123 their determination spans the fields of natural sciences, engineering, geology and medical 124 research. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory,[1] which has been 125 a remarkably successful contribution to the field of materials science. The BET method was 126 developed in the 1930s and is now the most widely used metric for the estimation of surface 127 areas of porous materials.[2] Since the BET method was first developed, there has been an 128 explosion in the field of nanoporous materials with the discovery of synthetic zeolites,[3] 129 nanostructured silicas,[4–6] metal-organic frameworks (MOFs),[7] and others. Despite its 130 widespread use, the manual calculation of BET surface areas causes a significant spread in 131 reported areas, resulting in reproducibility problems in both academia and industry. To probe 132 this, we have brought together 60 labs with strong track records in the study of nanoporous 133 materials. We provided eighteen adsorption isotherms and asked these researchers to 134 calculate the corresponding BET areas, resulting in a wide range of values for each one. We 135 show here that the reproducibility of BET area determination from identical isotherms is a 136 largely ignored issue, raising critical concerns over the reliability of reported BET areas in 137 the literature. To solve this major issue, we have developed a new computational approach 138 to accurately and systematically determine the BET area of nanoporous materials. Our 139 software, called BET Surface Identification (BETSI), expands on the well-known Rouquerol 140 criteria and makes, for the first time, an unambiguous BET area assignment possible.

scholarly journals How Reproducible Are Surface Areas Calculated from the BET Equation?

2021 ◽  
Author(s):  
Johannes Osterrieth ◽  
James Rampersad ◽  
David G. Madden ◽  
Nakul Rampal ◽  
Luka Skoric ◽  
...  
Keyword(s):  
Materials Science ◽  
Nanoporous Materials ◽  
Surface Areas ◽  
Wide Range ◽  
Bet Method ◽  
Metal Organic ◽  
Synthetic Zeolites ◽  
Bet Theory ◽  
First Time ◽  
Manual Calculation

Porosity and surface area analysis play a prominent role in modern materials science, where 123 their determination spans the fields of natural sciences, engineering, geology and medical 124 research. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory,[1] which has been 125 a remarkably successful contribution to the field of materials science. The BET method was 126 developed in the 1930s and is now the most widely used metric for the estimation of surface 127 areas of porous materials.[2] Since the BET method was first developed, there has been an 128 explosion in the field of nanoporous materials with the discovery of synthetic zeolites,[3] 129 nanostructured silicas,[4–6] metal-organic frameworks (MOFs),[7] and others. Despite its 130 widespread use, the manual calculation of BET surface areas causes a significant spread in 131 reported areas, resulting in reproducibility problems in both academia and industry. To probe 132 this, we have brought together 60 labs with strong track records in the study of nanoporous 133 materials. We provided eighteen adsorption isotherms and asked these researchers to 134 calculate the corresponding BET areas, resulting in a wide range of values for each one. We 135 show here that the reproducibility of BET area determination from identical isotherms is a 136 largely ignored issue, raising critical concerns over the reliability of reported BET areas in 137 the literature. To solve this major issue, we have developed a new computational approach 138 to accurately and systematically determine the BET area of nanoporous materials. Our 139 software, called BET Surface Identification (BETSI), expands on the well-known Rouquerol 140 criteria and makes, for the first time, an unambiguous BET area assignment possible.

scholarly journals Recent Trends in Covalent and Metal Organic Frameworks for Biomedical Applications

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 916 ◽  
Author(s):  
Georges Chedid ◽  
Ali Yassin
Keyword(s):  
Drug Delivery ◽  
Biomedical Applications ◽  
Materials Science ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
Great Promise ◽  
Surface Areas ◽  
Metal Organic ◽  
New Type ◽  
Recent Trends

Materials science has seen a great deal of advancement and development. The discovery of new types of materials sparked the study of their properties followed by applications ranging from separation, catalysis, optoelectronics, sensing, drug delivery and biomedicine, and many other uses in different fields of science. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) are a relatively new type of materials with high surface areas and permanent porosity that show great promise for such applications. The current study aims at presenting the recent work achieved in COFs and MOFs for biomedical applications, and to examine some challenges and future directions which the field may take. The paper herein surveys their synthesis, and their use as Drug Delivery Systems (DDS), in non-drug delivery therapeutics and for biosensing and diagnostics.

scholarly journals Metal-Organic Frameworks for Drug Delivery Applications

2021 ◽  
pp. 139-170
Author(s):  
Doaa Ahmed Ghareeb ◽  
Nessma Magdy Nasr
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Drug Delivery Systems ◽  
Metal Organic Frameworks ◽  
Stimuli Responsive ◽  
Surface Areas ◽  
Wide Range ◽  
Metal Organic ◽  
Delivery Vehicles ◽  
Structural Aspects

Metal-organic frameworks (MOFs) are based on metals and organic linkers; they possess large surface areas, suitable pore size and shape, wide range of chemical composition, and functionalized pore surface, which enable them for possible applications as delivery vehicles for therapeutic agents. The challenges include not only the development of new solids but also continuous improvements in the formulation and processing of the materials, including modifying the morphology and shape of the frameworks to fit the proposed applications of drug delivery. This chapter discussed enormous MOF-based stimuli responsive drug delivery systems, and considerable achievements have been made as a new avenue for drug delivery, their structural aspects, their applications in the controlled release of the drugs, and future view for development of drug controlled release researches using MOFs. Among the properties that must be developed and approved are the materials' toxicology, stability, their reproducibility of manufacture of MOFs in body's liquid, and pharmacokinetics of drug-loaded MOFs.

Study of the Structure and Properties of Carbon Gels from Abies Lignin and Tannins

2020 ◽  
pp. 109-121
Author(s):  
Nadezhda M. Mikova ◽  
Anatolii M. Zhizhaev ◽  
Ivan P. Ivanov ◽  
Maxim A. Lutoshkin ◽  
Boris N. Kuznetsov
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Lignin Content ◽  
Sol Gel ◽  
Surface Areas ◽  
Carbon Gels ◽  
Bet Method ◽  
Porous Volume ◽  
Carbon Gel ◽  
First Time

Carbon tannin-lignin-formaldehyde (TLF) gels were obtained for the first time by carbonization of organic xerogels synthesized by sol-gel condensation of formaldehyde with polyphenolic substances isolated from abies wood and bark – ethanol lignin and condensed tannins. The effect of the mass ratio of the tannins/lignin (T/L) components in the range 1:0 – 1:2 on the specific surface areas, porous volume, apparent density, and microstructure of carbon tannin-lignin-formaldehyde gels has been studied. It was found that the density of the carbon gels increases from 0.52 to 0.60 g/cm3 with a rises in the T/L ratio from 1:0 to 1:0.2 and 1:0.5 in the initial gel and then decreases to 0.20 and 0.13 g/cm3 with an increase in the lignin content to T/L ratios of 1:1 and 1:2, respectively. The study of the porous structure of carbon gels by the BET method showed that the carbon TLF gel obtained at a T/L ratio 1:2 is characterized by the highest specific surface area (538 m2/g). Using scanning electron microscopy, the structures of TF and TLF carbon gels have been studied. It has been established that the size of globular particles has a decisive influence on the structure of gels. The size of the globule particles increases with increasing of lignin content in the composition of the tannin-lignin-formaldehyde gel that leads to the formation of a less ordered structure of the carbon gel. The porous structure of TLF carbon gels obtained from abies polyphenolic substances can be regulated by varying the ratio of tannins:lignin. The obtained carbon gels can be used as sorbents and catalyst supports

Characterization and cation exchange properties of zeolite synthesized from fly ashes

1998 ◽  
Vol 13 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Weiping Ma ◽  
Paul W. Brown ◽  
Sridhar Komarneni
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Hydrothermal Conditions ◽  
Synthesis Conditions ◽  
Surface Areas ◽  
Wide Range ◽  
Bet Method ◽  
Fibrous Morphology ◽  
Zeolite P ◽  
Class F Fly Ash

Zeolite P was formed from class F fly ash under hydrothermal conditions. The fly ash was reacted with 2.8 or 5 M NaOH at 100 °C. Zeolite of the above type was produced regardless of the NaOH concentration or the addition of quartz, thus indicating its formation over a wide range of conditions. The zeolite produced was of the NaP-type with a fibrous morphology. Analysis of the pore structure of this zeolite by the BET method indicates a type II isotherm. The specific surface areas of synthesized zeolites increased from 28.5 to 41.1 m2/g when the NaOH concentration was increased from 2.8 to 5.0 M. This zeolite showed a significant selectivity for the uptake of Cs and Sr. Cs uptake ranged from 7.67 to 8.61 meq/100 g while that of Sr ranged from 9.8 to 10.54 meq/100 g. The value obtained depended on the specific synthesis conditions. These values are higher than those observed for tobermorite prepared from the same fly ash even though the tobermorite exhibited a higher specific surface area.

scholarly journals A modest method of synthesis Cu- based metal-organic frameworks using benzene dicarbocxylate as a ligan for promising candidate of flue gas CO2 adsorption

2021 ◽  
Vol 21 (3) ◽  
pp. 128-134
Author(s):  
MUTTAQIN MUTTAQIN ◽  
FARID IMAM HIDAYAT
Keyword(s):  
Metal Organic Framework ◽  
Average Pore Size ◽  
Metal Organic Frameworks ◽  
Font Size ◽  
Average Pore ◽  
Good Thermal Stability ◽  
Surface Areas ◽  
Small Pore ◽  
Bet Method ◽  
Metal Organic

Metal organic framework (MOF) is one of extraordinary materials in many technical field applications. One of them is as CO2 gas adsorbent. We studied, synthesized, and characterized Copper-based material, known as Metal organic frameworks (MOFs), using a solvothermal-based modification method. Copper salt (Cu (NO3)2. 3H2O) and benzene dicarboxylic acid (H2BDC) were mixed and then heated in an oven at 120°C, to produce low impurities, small pore and uniform particle size of materials called CuBDC. Infrared spectroscopy and XRD data confirmed the formation of CuBDC. Furthermore, the result showed that CuBDC frameworks have good thermal stability up to 330°C.  Thereafter SEM picture showed random, layered, and asymmetrical corners structure which is typical of triclinic crystal system. Lastly, specific surface areas and the porosity were analyzed using The Brunauer-Emmett-Teller (BET) method. It recorded 485 m2.g-1 of surface area while average pore volume and average pore size are 0.16 cm3.g-1 and 5.9 Å respectively.   @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536869121 1107305727 33554432 0 415 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; mso-ansi-language:IN; mso-fareast-language:IN;}div.WordSection1 {page:WordSection1;}

Electron spectroscopic imaging and diffraction

1991 ◽  
Vol 49 ◽  
pp. 706-707
Author(s):  
M. Rühle ◽  
J. Mayer ◽  
J.C.H. Spence ◽  
J. Bihr ◽  
W. Probst ◽  
...  
Keyword(s):  
Materials Science ◽  
Electron Spectroscopic Imaging ◽  
Magnetic Filter ◽  
Magnetic Imaging ◽  
Illumination System ◽  
Probe Size ◽  
Diffraction Patterns ◽  
Fritz Haber ◽  
Koehler Illumination ◽  
First Time

A new Zeiss TEM with an imaging Omega filter is a fully digitized, side-entry, 120 kV TEM/STEM instrument for materials science. The machine possesses an Omega magnetic imaging energy filter (see Fig. 1) placed between the third and fourth projector lens. Lanio designed the filter and a prototype was built at the Fritz-Haber-Institut in Berlin, Germany. The imaging magnetic filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient area detection. The energy dispersion at the exit slit (Fig. 1) results in ∼ 1.5 μm/eV which allows imaging with energy windows of ≤ 10 eV. The smallest probe size of the microscope is 1.6 nm and the Koehler illumination system is used for the first time in a TEM. Serial recording of EELS spectra with a resolution < 1 eV is possible. The digital control allows X,Y,Z coordinates and tilt settings to be stored and later recalled.

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

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