Study on the Effect of Different Template Agents on the Synthesis of MCM-48 Molecular Sieves

2021 ◽  
Vol 1020 ◽  
pp. 231-235
Author(s):  
Xin Xin Li ◽  
Mei Li ◽  
Liu Yi Dong ◽  
Kai Min Su ◽  
Yun He ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Crystallization Temperature ◽  
Molecular Sieves ◽  
Molar Ratio ◽  
Crystallization Time ◽  
Surface Areas ◽  
Specific Surface Areas

At present, most of molecular sieves (MCM-48) are prepared by using dual template agents. In this paper, the effect of different template agents on the synthesis of MCM-48 under the same conditions is studied. MCM-48 was synthesized by different combinations of templates (CTAB + TEAOH, CTAB + TBAB, CTAB + P123). The specific surface areas of them were compared under different crystallization temperature and different crystallization time. The results show that the specific surface area of MCM-48 prepared by CTAB + TEAOH is higher than that of other dual template agnets at the same crystallization time and temperature when the molar ratio of CTAB to another template is 9.

A Comparison of Methods for Determining Surface Areas of Carbon Black

1973 ◽  
Vol 46 (1) ◽  
pp. 192-203 ◽  
Author(s):  
R. A. Klyne ◽  
B. D. Simpson ◽  
M. L. Studebaker
Keyword(s):  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Areas ◽  
Furnace Black ◽  
Area Increase ◽  
Experimental Errors ◽  
Specific Surface Areas ◽  
Surface Area Increase

Abstract 1. The various tint tests correlate with each other—it does not make much difference which of the three procedures is used. The discrimination between similar blacks is comparable. Specific surface areas obtained by the three methods are comparable and differences appear to be due to experimental errors. (Compare Figures 5–7). 2. Surface areas larger than some 90 to 100 m2/g cannot be reliably determined from tint strength measurements alone. 3. Structure exerts a pronounced effect on tint strength of furnace blacks, especially above 90 to 100 m2/g. Porosity and/or composition are apparently also variables which affect tinting strength. 4. Densichron reflectance on the dry carbon black can be used to estimate specific surface areas up to about 140 m2/g; but, since theabsoluteerrorincreases as the specific surface area increases, this method loses some of its reliability at values above about 110 m2/g. The relative error in reflectance determinations does not vary greatly over the furnace-black range. Densichron reflectance is influenced by composition, evidently due to composition-related differences in optical properties of the carbons. 5. In CTAB adsorption measurements, titration errors and handling errors tend to be rather constant for blacks of different surface area. Hence, CTAB permits better discrimination among blacks of small particle size. 6. The errors in Densichron reflectance surface area increase with specific surface area. Hence, the deviations between CTAB and reflectance surface area which are due to experimental error increase with the surface area of the sample.

scholarly journals Preparation and characterization of high specific surface area Mn3O4 from electrolytic manganese residue

2010 ◽  
Vol 8 (5) ◽  
pp. 1059-1068 ◽  
Author(s):  
Tiefeng Peng ◽  
Longjun Xu ◽  
Hongchong Chen
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Magnetic Measurements ◽  
High Specific Surface Area ◽  
Surface Areas ◽  
Electrolytic Manganese ◽  
Electrolytic Manganese Residue ◽  
Specific Surface Areas

AbstractMn3O4 powders have been produced from Electrolytic Manganese Residue (EMR). After leaching of EMR in sulfuric acid, MnSO4 solution containing various ions was obtained. Purifying the solution obtained and then adding aqueous alkali to the purified MnSO4 solution, Mn(OH)2 was prepared. Two methods were employed to produce Mn3O4. One way was oxidation of Mn(OH)2 in aqueous phase under atmosphere pressure to obtain Mn3O4. The other way was roasting Mn(OH)2 precursors in the range of 500°C to 700°C. The prepared samples were investigated by using several techniques including X-ray powder diffraction (XRD), Fourier Transformation Infra-Red (FTIR) spectra, and Brunauer-Emmett-Teller (BET) specific surface area instrument. Particle distribution and magnetic measurements were carried out on laser particle size analyzer, vibrating sample magnetometer (VSM). Through XRD, FTIR and determination of total Mn content (TMC), the products prepared were confirmed to be a single phase Mn3O4. BET specific surface areas can reach to 32 m2 g−1. The results indicated that products synthesized by aqueous solution oxidation method had higher specific surface areas and smaller particle size than those prepared by means of roasting. However the products prepared using the above two methods showed no obvious differences in magnetic property.

scholarly journals Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

2018 ◽  
Vol 32 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Jolanta Cieśla ◽  
Zofia Sokołowska ◽  
Barbara Witkowska-Walczak ◽  
Kamil Skic
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Water Vapour ◽  
Specific Surface Area ◽  
Nitrogen Adsorption ◽  
Total Carbon ◽  
Arctic Zone ◽  
Surface Areas ◽  
Arctic Soils ◽  
Specific Surface Areas

AbstractWater vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0−1range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

SEM and BET Methods for Investigating the Structure and Morphology of Co - Ce Catalysts for Production of Light Olefins

2008 ◽  
Vol 61 (2) ◽  
pp. 144 ◽  
Author(s):  
Ali A. Mirzaei ◽  
Maryam Galavy ◽  
Vahid Eslamimanesh
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Catalytic Performance ◽  
Light Olefins ◽  
Molar Ratio ◽  
Surface Areas ◽  
Preparation Conditions ◽  
Bet Specific Surface Area ◽  
Before And After

Co–Ce catalysts prepared by the coprecipitation method were tested for production of light olefins. The effect of different preparation conditions including the [Co]/[Ce] molar ratio, aging time, calcination conditions, different supports, and loading of optimum support on the structure and catalytic performance of different catalysts were investigated. It was found that catalyst containing 80% Co/20% Ce/15% SiO2, which was aged for 2 h and calcined at 600°C for 6 h, is the optimum modified catalyst for the conversion of synthesis gas to light olefins. Characterization of both precursors and calcined catalysts (before and after the test) was carried out using scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) specific surface area measurements. The morphology of the catalysts was investigated by SEM and the surface areas of these catalysts were studied by BET. It was shown that all of the different preparation variables influenced the morphology and also the specific surface area of the catalyst precursors and calcined catalysts.

scholarly journals The Effects of Various Parameters of the Microwave-Assisted Solvothermal Synthesis on the Specific Surface Area and Catalytic Performance of MgF2 Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3566
Author(s):  
Yawen Wang ◽  
Zahra Gohari Bajestani ◽  
Jérôme Lhoste ◽  
Sandy Auguste ◽  
Annie Hémon-Ribaud ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Solvothermal Synthesis ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Microwave Assisted ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Nanoparticle Sizes

High-specific-surface-area MgF2 was prepared by microwave-assisted solvothermal synthesis. The influences of the solvent and the magnesium precursors, and the calcination atmospheres, on the nanoparticle sizes and specific surface areas, estimated by X-Ray Powder Diffraction, N2 sorption and TEM analyses, were investigated. Nanocrystallized (~7 nm) magnesium partially hydroxylated fluorides (MgF2−x(OH)x) with significant specific surface areas between 290 and 330 m2∙g−1 were obtained. After activation under gaseous HF, MgF2−x(OH)x catalysts underwent a large decrease of both their surface area and their hydroxide, rates as shown by their 19F and 1H solid-state NMR spectra. Expect for MgF2 prepared from the acetate precursor, an activity of 30–32 mmol/h∙g was obtained which was about 40% higher compared with that of MgF2 prepared using Trifluoroacetate method (21.6 mmol/h∙g).

scholarly journals Inhibition of tetrachloroethene and trichloroethene on methanogenesis in anaerobic sludges from various origins

2020 ◽  
Vol 81 (3) ◽  
pp. 544-549
Author(s):  
A. M. Wang ◽  
C. S. Hwu ◽  
C. H. Wu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Physical Factor ◽  
Anaerobic Treatment ◽  
Contaminated Groundwater ◽  
Biological Factors ◽  
Methanogenic Activity ◽  
Surface Areas ◽  
Specific Surface Areas

Abstract Nine anaerobic sludges were screened to obtain the most effective methanogenic inoculum for the anaerobic treatment of groundwater that is contaminated with tetrachloroethene (PCE) or trichloroethene (TCE). The selection was based on the toxicity of PCE or TCE to acetoclastic methanogens in different sludges. The effects of two biological factors, sludge origin and specific acetoclastic methanogenic activity, and a physical factor, specific surface area of sludge, on the degree of inhibition were examined and compared. The fifty percent inhibition concentrations (IC50) of PCE and TCE that were obtained from 30 °C batch inhibition tests ranged from 0.18 to 0.41 and 1.71 to 3.31 mM, respectively, for the examined sludges. The toxicity of the contaminants to anaerobic sludges did not depend on the two biological factors but was closely correlated with the specific surface area of sludge. Suspended sludges, which have higher specific surface areas than granular sludges, suffered much greater inhibition. This paper suggests the use of anaerobic granular sludges as inocula in bioreactors for treating PCE- and TCE-contaminated groundwater to reduce the effect of their inhibition.

scholarly journals Towards Macroporous α-Al2O3—Routes, Possibilities and Limitations

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1787
Author(s):  
Simon Carstens ◽  
Ralf Meyer ◽  
Dirk Enke
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Surface Areas ◽  
Alumina Membranes ◽  
Sol Gel Process ◽  
Specific Surface Areas ◽  
Α Al2o3 ◽  
Sol Gel Synthesis

This article combines a systematic literature review on the fabrication of macroporous α-Al2O3 with increased specific surface area with recent results from our group. Publications claiming the fabrication of α-Al2O3 with high specific surface areas (HSSA) are comprehensively assessed and critically reviewed. An account of all major routes towards HSSA α-Al2O3 is given, including hydrothermal methods, pore protection approaches, dopants, anodically oxidized alumina membranes, and sol-gel syntheses. Furthermore, limitations of these routes are disclosed, as thermodynamic calculations suggest that γ-Al2O3 may be the more stable alumina modification for ABET > 175 m2/g. In fact, the highest specific surface area unobjectionably reported to date for α-Al2O3 amounts to 16–24 m2/g and was attained via a sol-gel process. In a second part, we report on some of our own results, including a novel sol-gel synthesis, designated as mutual cross-hydrolysis. Besides, the Mn-assisted α-transition appears to be a promising approach for some alumina materials, whereas pore protection by carbon filling kinetically inhibits the formation of α-Al2O3 seeds. These experimental results are substantiated by attempts to theoretically calculate and predict the specific surface areas of both porous materials and nanopowders.

scholarly journals Green Synthesis Method and Application of NaP Zeolite Prepared by Coal Gasification Coarse Slag from Ningdong, China

2020 ◽  
Vol 10 (8) ◽  
pp. 2694 ◽  
Author(s):  
Wenxin Ji ◽  
Shiyue Zhang ◽  
Pengde Zhao ◽  
Shasha Zhang ◽  
Ning Feng ◽  
...  
Keyword(s):  
Specific Surface ◽  
Environmental Protection ◽  
Surface Area ◽  
Specific Surface Area ◽  
Coal Gasification ◽  
Synthesis Method ◽  
Ammonia Nitrogen ◽  
Raw Material ◽  
Molar Ratio ◽  
Crystallization Time

In view of the current and urgent environmental protection needs, the use of industrial solid waste in China’s Ningdong is becoming more and more important. In this paper, NaP zeolite with good physical properties is synthesized by using coal gasification coarse slag (CGCS) as the raw material, without the addition of a silicon and aluminum source, without the addition of a template agent, and without high-temperature calcination. Add a small amount of NaOH and deionized water to the CGCS to adjust the molar ratio to SiO2:Al2O3:Na2O:H2O = 5.2:1.0:5.0:100. The effects of aging time, crystallization temperature, and crystallization time parameters on synthetic zeolite were studied. The raw materials and the obtained zeolite were tested by XRF, XRD, SEM, FT-IR, TG-DSC, BET, and other technologies. The results show that the specific surface area of the synthesized NaP zeolite can reach 161.06 m2/g, which has the characteristics of large specific surface area, regular morphology, and high crystallinity. We obtained NaP zeolite through a simple and low-cost synthesis method. The synthesized NaP zeolite was used to simulate the removal of ammonia nitrogen in wastewater, and the optimal removal rate was 92.67%. Among them, Na+ plays an important role in the synthesis of NaP zeolite and ion exchange with NH4+. Our research provides new ideas for solving the large-scale accumulation of CGCS and treating ammonia nitrogen in industrial wastewater. Thus, it is a promising green environmental protection and “treating waste by waste” route.

scholarly journals Ultradrawing and Ultimate Tenacity Properties of Ultrahigh Molecular Weight Polyethylene Composite Fibers Filled with Nanosilica Particles with Varying Specific Surface Areas

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Jen-taut Yeh ◽  
Chuen-Kai Wang ◽  
Lu-Kai Huang ◽  
Chih-Chen Tsai ◽  
Wei-Yu Lai
Keyword(s):  
Molecular Weight ◽  
Specific Surface ◽  
Tensile Properties ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Surface Areas ◽  
Ultrahigh Molecular Weight ◽  
Specific Surface Areas ◽  
Nanosilica Particles

Original and/or functionalized nanosilica particles with a quoted specific surface area of 100, 300, and 600 m2/g, respectively, were used to investigate the influence of specific surface areas of nanosilica particles on ultradrawing and ultimate tensile properties of ultrahigh molecular weight polyethylene (UHMWPE), UHMWPE/nanosilica, and UHMWPE/functionalized nanosilica fibers. The specific surface areas of well-dispersed functionalized nanosilica particles in UHMWPE/functionalized nanosilica fibers can positively affect their ultradrawing, orientation, ultimate tensile properties, and “micro-fibrils” morphologies. Excellent orientation and ultimate tensile properties of UHMWPE/nanofiller fibers can be prepared by ultradrawing the UHMWPE/functionalized nanosilica as-prepared fibers with optimal contents of the best prepared functionalized nanosilica particles well dispersing in the as-prepared fibers. The ultimate tensile strength value of the best prepared UHMWPE/functionalized nanosilica drawn fiber reaches 7.6 GPa, which is about 2.3 times of those of the best prepared UHMWPE drawn fiber without addition of any nanofiller. Specific surface area, morphological and Fourier transform infrared analyses of original and functionalized nanosilica particles, and/or investigations of thermal, orientation factor, and ultimate tensile properties of as-prepared and/or drawn UHMWPE/functionalized nanosilica fibers were performed to understand the above improved ultradrawing and ultimate tensile properties of the UHMWPE/functionalized nanosilica as-prepared and/or drawn fibers.

Determination of low specific surface areas of minerals and oxides by gas–solid chromatography

1982 ◽  
Vol 60 (22) ◽  
pp. 2859-2862 ◽  
Author(s):  
Peter R. Tremaine ◽  
Alfred G. Wikjord ◽  
Jacques C. Leblanc
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Retention Volume ◽  
Volume Data ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Bet Equation

Gas–solid chromatography is shown to provide a method for measuring the specific surface area of non-porous particulate mineral or oxide samples in the range 0.005 to 0.5 m2 g−1 with precision as high as ±10%. Mesitylene is a convenient sorbate and was found to occupy an area of 71 ± 5 Å2 per molecule on silicate surfaces, by calibration with glass particles having well defined surface geometries. The rather low values obtained for the C parameter, when fitting retention volume data to the BET equation, suggest that the area occupied by mesitylene may be affected by the surface on which it is adsorbed. Hydrocarbon contaminants are a major interference. No specialized instrumentation is required.

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