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

Effect of Iron (III)-Doping on the Photocatalytic Activity of Titanium Dioxide Catalysts for Methylene Blue Degradation

2011 ◽  
Vol 117-119 ◽  
pp. 1088-1091
Author(s):  
Wen Churng Lin ◽  
Rui Liu ◽  
Wein Duo Yang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Effective Means ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Bet Specific Surface Area ◽  
Vis Spectroscopy

Iron-doped TiO2 photocatalyst powders were prepared by the sol–gel method and characterized by Brunauer–Emmett–Teller (BET)-specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Ultraviolet–Visible (UV-Vis) spectroscopy. Fe3+ doping in the TiO2 decreases the crystal grain size, increases the specific surface areas of powders, extends the absorption to visible light regions (400~500 nm), and lowers the photocatalytic activity for methylene blue (MB) degradation under UV irradiation. The photocatalytic degradation of MB in water was investigated as a function of the Fe3+ content in TiO2. It was found that under the irradiation of visible light, a small amount of Fe3+ dopant in TiO22 powders could obviously enhance the photocatalytic activity. When the Fe3+ content was in the range of 0.03–0.1 mol%, the photocatalytic activity of the samples was higher than that of undoped TiO2. Appropriate content of Fe-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.

Behavior of Cs in Grimsel granodiorite: sorption on main minerals and crushed rock

2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Eveliina Muuri ◽  
Jussi Ikonen ◽  
Minja Matara-aho ◽  
Antero Lindberg ◽  
Stellan Holgersson ◽  
...  
Keyword(s):  
Specific Surface ◽  
Test Site ◽  
Potassium Feldspar ◽  
Distribution Coefficients ◽  
Crushed Rock ◽  
Surface Areas ◽  
Bet Method ◽  
Grimsel Test Site ◽  
Specific Surface Areas ◽  
Phreeqc Modelling

AbstractIn this study the sorption of cesium was investigated on four different minerals; quartz, plagioclase, potassium feldspar and biotite as well as granodiorite obtained from the Grimsel test site in Switzerland. The experiments were conducted in the presence of the weakly saline Grimsel groundwater simulant by determining the distribution coefficients using batch sorption experiments and PHREEQC-modelling across a large concentration range. In addition, the purity of the minerals was measured by XRD and the specific surface areas by BET method using krypton. The distribution coefficients of cesium were largest on biotite (0.304 ± 0.005 m

scholarly journals Study of sepiolite from Goles (Kosovo, Yugoslavia). II. Acid activation

2002 ◽  
Vol 67 (7) ◽  
pp. 499-506 ◽  
Author(s):  
Marina Radojevic ◽  
Vidojko Jovic ◽  
Dragomir Karaulic ◽  
Dragomir Vitorovic
Keyword(s):  
Specific Surface ◽  
Chemical Treatment ◽  
Acid Treatment ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Acid Activation ◽  
Surface Areas ◽  
Bet Method ◽  
Specific Surface Areas ◽  
Enhanced Adsorption

The changes in the pore structure and adsorption properties of sepiolite from Goles resulting from treatment with 4MHCl for various periods of time were investigated. The BET method specific surface areas, pore volumes and f ? plots were determined by nitrogen adsorption. The surface area progressively increased during the 70 hours of acid treatment, when a maximum was attained. The differences in the adsorption properties of the original and the acid treated sepiolite were evaluated by comparison of adsorption isotherms obtained with benzene, n-hexane, methanol and isooctane. The enhanced adsorption of isooctane was of great interest, since the sorption of this compound on natural sepiolites is generally very limited. The results suggest that chemical treatment of sepiolite with 4MHCl for 70 h produces an adsorbent of optimal porosity and other adsorption properties.

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.

Sonication-Assisted Synthesis of Molybdenum Disulfide Aerogel for the Electrode Materials of Supercapacitors

NANO ◽  
2019 ◽  
Vol 14 (05) ◽  
pp. 1950055
Author(s):  
Qiang Zhang ◽  
Wenyuan He ◽  
Yinmin Wang ◽  
Dazhao Pei ◽  
Xuejun Zheng
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Molybdenum Disulfide ◽  
Freeze Drying ◽  
Electrode Materials ◽  
Hydrothermal Reaction ◽  
High Specific Capacitance ◽  
Electrochemical Performances ◽  
Surface Areas ◽  
Charge Discharge

The sonication processing was added in front of the freeze-drying as an intermediate processing before the molybdenum disulfide (MoS2) aerogel was synthesized. It is distinguishing with the traditional hydrothermal reaction to combine the sonication processing and freeze-drying in our method. The structure, morphology, specific surface area and pore size distribution were characterized, and the electrochemical performances were measured in 0.5[Formula: see text]M Na2SO4 electrolyte for the MoS2 aerogel and flower-like MoS2. As for comparison, they are of porous structure and microsphere structure, and their specific surface areas are 55.14[Formula: see text]m2[Formula: see text]g[Formula: see text] and 38.12[Formula: see text]m2[Formula: see text]g[Formula: see text]. The specific capacitances are 166.7[Formula: see text]F[Formula: see text]g[Formula: see text] and 119.2[Formula: see text]F[Formula: see text]g[Formula: see text] at the scan rate of 5[Formula: see text]mV[Formula: see text]s[Formula: see text], and the capacity retentions are 87.7% and 81.6% after 3000 charge/discharge cycles. For the enhanced mechanism, the high specific surface of the MoS2 aerogel causes high specific capacitance, and the unique porous structure could buffer volume expansion to improve retention ability during charge/discharge processes. The MoS2 aerogel may thus be a promising electrode material for supercapacitors.

Synthesis, Characterization and Photocatalytic Activity of Copper (II)-Doped Titanium Dioxide Powders

2011 ◽  
Vol 391-392 ◽  
pp. 728-731 ◽  
Author(s):  
Wen Churng Lin ◽  
Wein Duo Yang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Effective Means ◽  
Sol Gel ◽  
Particle Growth ◽  
X Ray ◽  
Surface Areas ◽  
Vis Spectroscopy

Different concentration of copper (II) doped TiO2 photocatalyst powders were synthesized through the sol-gel method and characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface area, transmission electron microscopy (TEM), and Ultraviolet–Visible (UV-Vis) spectroscopy. Cu2+-doping in the TiO2 promotes the particle growth, decreases the specific surface areas of powders, extends the absorption to visible light regions, and exhibits the vis-photocatalytic activity for methylene blue (MB) degradation. Appropriate content of Cu2+-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.

The in vitro Uptake of Fluoride by Secretory and Maturation Stage Bovine Enamel

1988 ◽  
Vol 67 (2) ◽  
pp. 487-490 ◽  
Author(s):  
R.A. Fridell ◽  
A. Lussi ◽  
M.A. Crenshaw ◽  
J.W. Bawden
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Organic Matrix ◽  
Maturation Stage ◽  
Fluoride Uptake ◽  
Surface Areas ◽  
Bet Method ◽  
Two Stages ◽  
Bovine Enamel

The objectives of this study were to determine the specific surface area of secretory-stage and of maturation-stage enamel, to compare the fluoride uptake by isolated enamel at these two stages on a surface-area basis, and to examine the effect of the organic matrix on the fluoride uptake by whole enamel. Fetal bovine secretory and maturation stage enamel samples were collected, and a portion of the enamel at each developmental stage was treated with hydrazine for removal of the organic matrix. The specific surface areas of the enamel mineral, as determined by the multi-point BET method, were 59.3 m2/ g in the secretory stage and 37.9 m2/g in the maturation stage. Whole and deproteinated enamel samples were equilibrated in buffered solutions containing 10 -5 to 10-3 mol/L fluoride, and the uptake was measured with a fluoride specific electrode. The results indicate that the in vitro fluoride uptake was controlled solely by the surface area of the apatitic mineral and that the organic matrix did not contribute to the fluoride uptake.

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 Preliminary evaluation of resorcinol-formaldehyde carbon gels for water pollutants removal

2017 ◽  
Vol 10 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Seiichiro Yoshida ◽  
Takeshi Mori ◽  
Shin R. Mukai
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Resorcinol Formaldehyde ◽  
Water Pollutants ◽  
Carbon Gels ◽  
Oxidized Carbon ◽  
Carbon Gel ◽  
Pollutants Removal

Abstract The present work was aimed to evaluate the suitability of resorcinol-formaldehyde carbon gels as adsorbent for water pollutants removal. The carbon gels were characterized using N2 adsorption-desorption isotherm for specific surface area, and Fourier transform infrared (FTIR) for surface functional groups. Methylene blue and cesium were employed as model water pollutants. Results show that the un-oxidized carbon gel, despite its lower specific surface area (333 m2/g) displayed a 118 mg/g removal of methylene blue, that is higher than 35 mg/g by the oxidized carbon gel (418 m2/g). The evaluation of adsorption kinetics revealed a lower pseudo-first order rate constant of 0.088 h-1 for 10 mg/L methylene blue adsorption. A positive effect of surface oxidation was demonstrated for cesium adsorption. On molar basis, however, the oxidized carbon gel exhibits a selective removal towards methylene blue compared to cesium. Carbon gel is a promising candidate for water pollutants removal, and further treatment needs to be sought to boost its performance.

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