scholarly journals ACID ACTIVATION OF PRRENJAS CLAY MINERAL

2018 ◽  
Vol 4 (7) ◽  
Author(s):  
Altin Mele ◽  
Krenaida Taraj ◽  
Arjan Korpa
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Clay Mineral ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Gas Adsorption ◽  
Exchange Capacity ◽  
Acid Activation ◽  
Composition Structure ◽  
Adsorption Desorption

Prrenjas clay mineral is found in southeast Albania and has a high content on bentonite. Theinfluence of the sulphuric acid activation on the composition, structure and surface properties ofPrrenjas clay mineral is investigated in this study by means of elemental chemical analysis, X-RayDiffractometry, IR Spectroscopy and gas adsorption-desorption measurement. H2SO4concentrations of 0.143 M, 0.232 M, 0.371 M, 0.537 M, 0.734 M, 0.927 M and 1.456 M were used inthe treatment of samples. The treatment by increasing the acid concentration brings the leaching ofAl3+, Fe2+, Mg2+ from the clay structure. The specific surface area and the pore volume of the claysamples increases respectively from 83 m2/g and 0.069 cm3/g for the untreated clay to 420 m2/g and0.384 cm3/g for the clay mineral treated with 1.456 M H2SO4 solution. New mesopores were createdduring the acid activation mainly in the range of 2 – 8 nm. For the samples treated with 0.927 Mand 1.456 M solutions the increase in specific surface area and pore volume is very high. Thecationic exchange capacity decreases steadily with the concentration of H2SO4 used for thetreatment.

Effects of extraction process on the dried cell wall pore structure of messmate heartwood

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6074-6082
Author(s):  
Weikai Wang ◽  
Minghan Li ◽  
Jiabin Cai
Keyword(s):  
Cell Wall ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Gas Adsorption ◽  
Extraction Process ◽  
Micropore Volume ◽  
Adsorption Method

In order to study the effects of a messmate heartwood extraction process on its cell wall pore structure and its drying ability, its nanopore structure was explored after via gas adsorption technology. Specifically, the messmate heartwood particles were extracted with methanol, and then the cell wall pore structure of the original and extracted samples were evaluated by N2 and CO2 sorption and pycnometer methods, respectively. Overall, compared with the original samples, the cell wall porosity, micropore volume, mesopore volume, BET specific surface area, and specific surface area of the micropores of the extracted messmate heartwoods increased by 2.55%, 0.007 cm3/g, 0.0014 cm3/g, 0.24 m2·g-1, and 21.9 m2·g-1, respectively. The cell wall pore volume measured via the gas adsorption method was smaller than the measurement from the pycnometer method. The results indicated that the presence of extractives made the messmate cell wall have a decreased pore volume and porosity, which may be one of the reasons messmate wood is difficult to dry. Messmate extractives primarily were present in the micropores of the cell wall in the range of 0.4 nm to 0.7 nm. However, gas sorption technology could not detect all the pores in the cell wall of the messmate heartwood sample.

scholarly journals The influence factors for gas adsorption with different ranks of coals

2017 ◽  
Vol 36 (3-4) ◽  
pp. 904-918 ◽  
Author(s):  
Deyong Guo ◽  
Xiaojie Guo
Keyword(s):  
Moisture Content ◽  
Specific Surface ◽  
Pore Structure ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Gas Adsorption ◽  
Total Pore Volume ◽  
Factors Influencing

In this paper, scanning electron microscopy, low-temperature N2 adsorption and CH4 isothermal adsorption experiments were performed on 11 coal samples with Ro,max between 0.98 and 3.07%. The pore structure characteristics of coals (specific surface area, total volume distribution) were studied to assess the gas adsorption capacity. The results indicate that there is significant heterogeneity on coal surface, containing numerous channel-like pores, bottle-shaped pores and wedge-shaped pores. Both Langmuir volume (VL) and Langmuir pressure (PL) show a stage change trend with the increase of coalification degree. For different coalification stages, there exist different factors influencing the VL and PL values. For low-rank coals (Ro,max < 1.1%), the increase of VL values and decrease of PL values are mainly due to the abundant primary pore and fracture within coal. For middle-rank coals (1.1% < Ro,max < 2.1%), the moisture content, vitrinite content and total pore volume are all the factors influencing VL, and the reduction of PL is mainly attributed to the decrease of moisture content and inertinite content. Meanwhile, this result is also closely related to the pore shape. For high-rank coals (Ro,max > 2.1%), VL values gradually increase and reach the maximum. When the coal has evolved into anthracite, liquid hydrocarbon within pore begins pyrolysis and gradually disappears, and a large number of macropores are converted into micropores, leading to the increase of specific surface area and total pore volume, corresponding to the increase of VL. In addition, the increase of vitrinite content within coal also contributes to the increase of VL. PL, reaches the minimum, indicating that the adsorption rate reaches the largest at the low pressure stage. The result is mainly controlled by the specific surface area and total pore volume of coal samples. This research results will provide a clearer insight into the relationship between adsorption parameters and coal rank, moisture content, maceral composition and pore structure, and it is of great significance for better assessing the gas adsorption capacity.

scholarly journals Synthesis of micro-mesopores flowerlike γ-Al2O3 nano-architectures

2014 ◽  
Vol 79 (8) ◽  
pp. 1007-1017 ◽  
Author(s):  
Mozaffar Abdollahifar ◽  
Reza Zamani ◽  
Ehsan Beiygie ◽  
Hosain Nekouei
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Total Pore Volume ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Adsorption Desorption

The micro-mesopores flowerlike ?-Al2O3 nano-architectures have been synthesized by thermal decomposition method using the synthesized AlOOH (boehmite) as precursor. After calcination at 500?C for 5 h, the obtained flowerlike ?-Al2O3 has similar structure like the AlOOH precursor. X-ray diffraction (XRD), FTIR, TG, FESEM and TEM techniques were used to characterize morphology and structure of the synthesized samples. The specific surface area (BET), pore volume and pore-size distribution of the products were determined by N2 adsorption-desorption measurements. The flowerlike ?-Al2O3 showed BET high specific surface area 148 m2 g-1 with total pore volume 0.59 cm3 g-1.

scholarly journals Chemical Composition and Porosity Characteristics of Various Calcium Silicate-Based Endodontic Cements

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Seok Woo Chang
Keyword(s):  
Chemical Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Calcium Silicate ◽  
Pore Diameter ◽  
Clinical Performance ◽  
Powder Analysis ◽  
Adsorption Desorption

Chemical composition and porosity characteristics of calcium silicate-based endodontic cements are important determinants of their clinical performance. Therefore, the aim of this study was to investigate the chemical composition and porosity characteristics of various calcium silicate-based endodontic cements: MTA-angelus, Bioaggregate, Biodentine, Micromega MTA, Ortho MTA, and ProRoot MTA. The specific surface area, pore volume, and pore diameter were measured by the porosimetry analysis of N2 adsorption/desorption isotherms. Chemical composition and powder analysis by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were also carried out on these endodontic cements. Biodentine and MTA-angelus showed the smallest pore volume and pore diameter, respectively. Specific surface area was the largest in MTA-angelus. SEM and EDS analysis showed that Bioaggregate and Biodentine contained homogenous, round and small particles, which did not contain bismuth oxide.

The Influence of Acid Treatment on the Nanostructure and Textural Properties of Bentonite Clays

2005 ◽  
Vol 494 ◽  
pp. 339-344 ◽  
Author(s):  
Z. Vuković ◽  
A. Milutinović-Nikolić ◽  
J. Krstić ◽  
A. Abu-Rabi ◽  
T. Novaković ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Concentration ◽  
Pore Volume ◽  
Acid Treatment ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Acid Activation ◽  
Bentonite Clays

The nanostructure and textural properties of acid-activated bentonite clays from the Bogovina coalmine were investigated. The acid activation was performed with HCl in the concentration range 1.5-7.5 M. The atomic force microscopy followed by image analysis was used in order to establish the influence of the acid treatment on the size of bentonite particles. Nitrogen adsorption-desorption isotherms at -196 °C were used to estimate the specific surface area, pore volume and pore size distribution. The acid treatment reduces the size of bentonite particles and increases the specific surface area and pore volume of the investigated bentonites. These effects are improved by increasing the acid concentration up to 4.5 M HCl. Further increase in acid concentration does not result in development of new porous structure.

The Adsorption/Desorption Dynamics Properties of N-Alkanes in Light Naphtha on 5A Zeolites

2013 ◽  
Vol 807-809 ◽  
pp. 2643-2646
Author(s):  
Xiang Ji ◽  
Qing Sheng Zhang ◽  
Qun Cui ◽  
Hai Yan Wang
Keyword(s):  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Fixed Bed ◽  
Light Naphtha ◽  
Bet Specific Surface Area ◽  
Purge Gas ◽  
Adsorption Desorption

Self-made JH4 zeoite was characterized by BET, mercury and other methods. The dynamic adsorption capacity of nC5/nC6 in light naphtha on JH4 zeolite fixed bed was investigated. The effect of cyclic purge exhaust composition, which simulate different condensation conditions, on desorption performance of JH4 zeolite bed was studied. The results shows that, the microporous BET specific surface area and pore volume of JH4 zeolite is 710.05 m2/g and 0.32 cm3/g; macropore specific surface area and pore volume is 3.64 m2/g and 0.29 cm3/g, respectively. Under the adsorption conditions of 0.1 MPa, 165 °C, adsorption capacity of n-pentane and n-hexane in light naphtha on JH4 zeolite reaches, 7.24 g/100gadsand 3.11 g/100gadsrespectively.If the content of pentane and hexane achieves 3.68% and 0.21% in nitrogen purge gas, total desorption amount of JH4 zeolite is 2.07 g/100gads, falling 60.19% than that of pure N2purge.

Synthesis, Characterization and Gas Adsorption of Titania Nanotubes

2011 ◽  
Vol 194-196 ◽  
pp. 446-449
Author(s):  
Bey Fen Leo ◽  
Kim Han Tan ◽  
Meng Nee Ng ◽  
Mohd Rafie Johan
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Gas Adsorption ◽  
Average Particle Size ◽  
Transformation Process ◽  
Titania Nanotubes ◽  
Average Particle ◽  
Naoh Solution ◽  
Adsorption Desorption

Titania nanotubes (TNTs) have been successfully synthesized by hydrothermal treatment of anatase TiO2 powder in NaOH solution at 110°C for 90 hours and then annealed at the temperature of 400°C. The morphology and crystalline structure of the nanotubes were characterized by using transmission electron microscopy (TEM) and X-ray diffraction (XRD). The average specific surface area of the particle was probed using gas adsorption-desorption measurements, and average particle size was calculated from the specific surface area. Based on the microscopic observations on the transformation process, it indicated that the formation of nanotubular products remained in their shape after the annealing process. While XRD results confirmed the nanotubes were composed of pure anatase TiO2 nanoparticles.

Fuels Desulphurisation by Adsorbtion on Fe / Bentonite

2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Adsorption Process ◽  
Continuous System ◽  
Gas Oil ◽  
Average Pore ◽  
Atmospheric Distillation

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.

scholarly journals Nanometer Pore Structure Characterization of Taiyuan Formation Shale in the Lin-Xing Area Based on Nitrogen Adsorption Experiments

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Chenlong Ding ◽  
Jinxian He ◽  
Hongchen Wu ◽  
Xiaoli Zhang
Keyword(s):  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Shale Gas ◽  
Pore Volume ◽  
Ordos Basin ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Taiyuan Formation

Ordos Basin is an important continental shale gas exploration site in China. The micropore structure of the shale reservoir is of great importance for shale gas evaluation. The Taiyuan Formation of the lower Permian is the main exploration interval for this area. To examine the nanometer pore structures in the Taiyuan Formation shale reservoirs in the Lin-Xing area, Northern Shaanxi, the microscopic pore structure characteristics were analyzed via nitrogen adsorption experiments. The pore structure parameters, such as specific surface area, pore volume, and aperture distribution, of shale were calculated; the significance of the pore structure for shale gas storage was analyzed; and the main controlling factors of pore development were assessed. The results indicated the surface area and hole volume of the shale sample to be 0.141–2.188 m2/g and 0.001398–0.008718 cm3/g, respectively. According to the IUPAC (International Union of Pure and Applied Chemistry) classification, mesopores and macropores were dominant in the pore structure, with the presence of a certain number of micropores. The adsorption curves were similar to the standard IV (a)-type isotherm line, and the hysteresis loop type was mainly similar to H3 and H4 types, indicating that most pores are dominated by open type pores, such as parallel plate-shaped pores and wedge-shaped slit pores. The micropores and mesopores provide the vast majority of the specific surface area, functioning as the main area for the adsorption of gas in the shale. The mesopores and macropores provide the vast majority of the pore volume, functioning as the main storage areas for the gas in the shale. Total organic carbon had no notable linear correlation with the total pore volume and the specific surface area. Vitrinite reflectance (Ro) had no notable correlation with the specific surface area, but did have a low “U” curve correlation with the total pore volume. There was no relationship between the quartz content and specific surface area and total pore volume. In addition, there was no notable correlation between the clay mineral content and total specific surface area and total pore volume.

The relationship between geotechnical index properties and the pore-size distribution of compacted clayey silts

2015 ◽  
Vol 22 (6) ◽  
Author(s):  
Nazile Ural
Keyword(s):  
Specific Surface ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Correlation Coefficients ◽  
Liquid Limit ◽  
Index Properties

AbstractIn this study, the relationships between geotechnical index properties and the pore-size distribution of compacted natural silt and artificial soil mixtures, namely, silt with two different clays and three different clay percentages (10%, 20%, and 40%), were examined and compared. Atterberg’s limit tests, standard compaction tests, mercury intrusion porosimetry, X-ray diffraction, scanning electron microscopy (SEM) analysis, and Brunauer-Emmett-Teller specific surface analysis were conducted. The results show that the liquid limit, the cumulative pore volume, and specific surface area of artificially mixed soils increase with an increase in the percentage of clay. The cumulative pore volume and specific surface area with geotechnical index properties were compared. High correlation coefficients were observed between the specific areas and both the liquid limit and the plasticity index, as well as between the cumulative pore volume and both the clay percentage and the

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