scholarly journals The influence of modification on structural, textural and adsorption properties of bentonite

2008 ◽  
Vol 62 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Natasa Jovic-Jovicic ◽  
Aleksandra Milutinovic-Nikolic ◽  
Ivan Grzetic ◽  
Predrag Bankovic ◽  
Branislav Markovic ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Interplanar Spacing ◽  
Bentonite Clay ◽  
Textural Properties ◽  
Exchangeable Cations ◽  
Adsorption Properties ◽  
Microporous Material ◽  
X Ray

Natural bentonite clay from the Bogovina locality in Serbia was Na-exchanged and modified using hexadecyll-trimethylammonium bromide as surfactant and organobentonite was obtained. The influence of modifications on the structural, textural and sorption properties of bentonite was investigated. It was estimated that modifications solely replace exchangeable cations in smectite layers, whereas other admixture minerals (quartz, calcite, feldspar) in bentonite remain unaffected. According to X-ray results the modification lead to changes in the smectite structure by either decreasing, for Na-bentonite, or increasing, for organobentonite, the interplanar spacing, JQOI- The appearance of three new bands in IR spectra of HDTMA-bentonite comparing to those of raw and Na-bentonite assigned to the methylene vibrations confirmed the embedding of aliphatic cations into smectite structure. In organobentonite a significant change in textural properties was observed. In particular, specific surface area dramatically decreased while originally meso and microporous material became almost completely non-porous. Despite almost insignificant specific surface area the synthesized organobentonite due to gained organophyllity of its surface exhibits exquisite adsorption properties toward investigated textile dyes having adsorption capacity approx. 2 times higher than activated carbon.

Removal of Acid Textile Dye from the Aqueous Solution by a New Adsorbent Obtained from Waste Cotton from the Garment Plant

2020 ◽  
Vol 42 (5) ◽  
pp. 728-728
Author(s):  
Aleksandra Micic Aleksandra Micic ◽  
Dragan Djordjevic Dragan Djordjevic ◽  
Ivona Jankovic Castvan Ivona Jankovic Castvan ◽  
Nenad Cirkovic Nenad Cirkovic ◽  
Bratislav Todorovic Bratislav Todorovic
Keyword(s):  
Aqueous Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Adsorption Process ◽  
Bulk Material ◽  
Textural Properties ◽  
Textile Dye ◽  
Acid Dye ◽  
Microporous Material

The paper investigates the possibility of removing acid dye from the aqueous solution by an adsorption process on new adsorbent prepared from waste cotton textile from the ready-made garment industry. It is a waste generated during the cutting of the layers of cotton knitwear, which is practically the product from the textile cutting process. The obtained adsorbent is a bulk material with heterogeneous porous particles, of ragged shapes. In particle interiors, there are pronounced cracks, cavities and channels that form the basis of microporous material. The qualitative and quantitative characterization of the obtained adsorbent shows that this is a relatively porous material where the carbon is dominant in the chemical composition. The results of textural properties of new adsorbent from cotton knitwear waste show different parameters which with their numerous values characterize the specific surface area, pore volume or pore diameter. It can be said that the obtained new adsorbent has micropores and small mesopores, which produce a high specific surface area. During adsorption, the longer contact time causes a greater amount of dye on the adsorbent, i.e. with the duration of the adsorption process the dye concentration in the solution decreases. A number of isotherms of two- (Langmuir, Freundlich and Jovanovic), three- (Toth, Sips and Radke-Prausnitz), and four-parameter models (Fritz-Schlunder and Marczewski-Jaroniec) were used to describe the adsorption process. The four-parameter isotherms are best covered by experimental points and most accurately describe the events of adsorption of acid dye on the surface and in the interior of the new adsorbent particles obtained from ready–made garment cotton waste. The results of this research suggest the possibility of practical application in the decolorization of the colored waste waters of the textile industry providing a contribution to protecting the environment from both an economic and a practical point of view.

scholarly journals Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1230
Author(s):  
Fabien Léonard ◽  
Zhen Zhang ◽  
Holger Krebs ◽  
Giovanni Bruno
Keyword(s):  
Computed Tomography ◽  
Specific Surface ◽  
Ammonium Nitrate ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Fuel Oil ◽  
X Ray ◽  
Oil Retention ◽  
X Ray Computed

The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.

scholarly journals Preparation of Zirconia Nanofibers by Electrospinning and Calcination with Zirconium Acetylacetonate as Precursor

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1067 ◽  
Author(s):  
Vyacheslav V. Rodaev ◽  
Svetlana S. Razlivalova ◽  
Andrey O. Zhigachev ◽  
Vladimir M. Vasyukov ◽  
Yuri I. Golovin
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Heterogeneous Catalysts ◽  
Tetragonal Zirconia ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
X Ray ◽  
Adsorption Analysis

For the first time, zirconia nanofibers with an average diameter of about 75 nm have been fabricated by calcination of electrospun zirconium acetylacetonate/polyacrylonitrile fibers in the range of 500–1100 °C. Composite and ceramic filaments have been characterized by scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption analysis, energy-dispersive X-ray spectroscopy, and X-ray diffractometry. The stages of the transition of zirconium acetylacetonate to zirconia have been revealed. It has been found out that a rise in calcination temperature from 500 to 1100 °C induces transformation of mesoporous tetragonal zirconia nanofibers with a high specific surface area (102.3 m2/g) to non-porous monoclinic zirconia nanofibers of almost the same diameter with a low value of specific surface area (8.3 m2/g). The tetragonal zirconia nanofibers with high specific surface area prepared at 500 °C can be considered, for instance, as promising supports for heterogeneous catalysts, enhancing their activity.

Study of Heating Effect on Specific Surface Area, and Changing Optical Properties of ZnO Nanocrystals

2011 ◽  
Vol 403-408 ◽  
pp. 1205-1210
Author(s):  
Jaleh Babak ◽  
Ashrafi Ghazaleh ◽  
Gholami Nasim ◽  
Azizian Saeid ◽  
Golbedaghi Reza ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Energy Gap ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Zno Nanocrystal

In this work ZnO nanocrystal powders have been synthesized by using Zinc acetate dehydrate as a precursor and sol-gel method. Then the products have been annealed at temperature of 200-1050°C, for 2 hours. The powders were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence (PL) spectroscopy. The morphology of refrence ZnO nanoparticles have been studied using Transmission Electron Microscope (TEM). During the annealing process, increase in nanocrystal size, defects and energy gap quantitative, and decrease in specific surface area have been observed.

scholarly journals Low-Temperature Synthesis of Monolithic Titanium Carbide/Carbon Composite Aerogel

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2527
Author(s):  
Tingting Niu ◽  
Bin Zhou ◽  
Zehui Zhang ◽  
Xiujie Ji ◽  
Jianming Yang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Electron Microscope ◽  
Low Temperature ◽  
Titanium Carbide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Composite ◽  
Composite Aerogel ◽  
X Ray

Resorcinol-formaldehyde/titanium dioxide composite (RF/TiO2) gel was prepared simultaneously by acid catalysis and then dried to aerogel with supercritical fluid CO2. The carbon/titanium dioxide aerogel was obtained by carbonization and then converted to nanoporous titanium carbide/carbon composite aerogel via 800 °C magnesiothermic catalysis. Meanwhile, the evolution of the samples in different stages was characterized by X-ray diffraction (XRD), an energy-dispersive X-ray (EDX) spectrometer, a scanning electron microscope (SEM), a transmission electron microscope (TEM) and specific surface area analysis (BET). The results showed that the final product was nanoporous TiC/C composite aerogel with a low apparent density of 339.5 mg/cm3 and a high specific surface area of 459.5 m2/g. Comparing to C aerogel, it could also be considered as one type of highly potential material with efficient photothermal conversion. The idea of converting oxide–carbon composite into titanium carbide via the confining template and low-temperature magnesiothermic catalysis may provide new sight to the synthesis of novel nanoscale carbide materials.

Preparation of Nitrogen-Deficient Graphitic Carbon Nitride with a Large Specific Surface Area by Melt Pretreatment and Its Photocatalytic Performance

NANO ◽  
2020 ◽  
Vol 15 (06) ◽  
pp. 2050079
Author(s):  
Xuelei Li ◽  
Jinfeng Bai ◽  
Jiaqi Li ◽  
Chao Li ◽  
Junru Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Nitride ◽  
Mesoporous Structure ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Large Specific Surface Area ◽  
X Ray

In this study, nitrogen-deficient graphitic carbon nitride (M-LS-g-C3N4) with a mesoporous structure and a large specific surface area was obtained by calcination after melt pretreatment using urea as a precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-Vis, ESR and photoluminescence (PL) were used to characterize the structure, morphology and optical performance of the samples. The TEM results showed the formation of a mesoporous structure on the 0.1[Formula: see text]M-LS-g-C3N4 surface. The porous structure led to an increase in the specific surface area from 41.5[Formula: see text]m2/g to 124.3[Formula: see text]m2/g. The UV-Vis results showed that nitrogen vacancies generated during the modification process reduced the band gap of g-C3N4 and improved the visible light absorption. The PL spectra showed that the nitrogen defects promoted the separation of photogenerated electron–hole pairs. In the visible light degradation of methyl orange (MO), the reaction rate constant of 0.1[Formula: see text]M-LS-g-C3N4 reached 0.0086[Formula: see text][Formula: see text], which was 5.05 times that of pure g-C3N4. Superoxide radicals and photogenerated holes were found to be the main active species in the reaction system. This study provides an efficient, green and convenient means of preparing graphitic carbon nitride with a large specific surface area.

Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950080
Author(s):  
Hao Hu ◽  
Xiaogang Sun ◽  
Wei Chen ◽  
Jie Wang ◽  
Xu Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electric Double Layer ◽  
X Ray ◽  
Nitrogen Doped ◽  
Conductive Additive ◽  
Double Layer Capacitors ◽  
Boron Nitrogen

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50[Formula: see text]mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19[Formula: see text]F/g. Also, we observe that the maximum power density is close to 220[Formula: see text]W/kg (700[Formula: see text]mA/g), and the energy density can arrive 9.31[Formula: see text]Wh/kg (50[Formula: see text]mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220[Formula: see text]W/kg when the energy density keeps at 3.46[Formula: see text]Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

The Carbon Deposition during Iron Ore Reduction in Carbon Monoxide

2012 ◽  
Vol 625 ◽  
pp. 243-246
Author(s):  
Shu Hua Geng ◽  
Wei Zhong Ding ◽  
Shu Qiang Guo ◽  
Xiong Gang Lu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Iron Ore ◽  
Iron Reduction ◽  
Carbon Deposition ◽  
Reduction Process ◽  
Ore Reduction ◽  
X Ray ◽  
Iron Ore Reduction

Iron ore reduction and carbon deposition in pure CO was investigated by using thermogravimetric (TG) method over the temperature range of 0-1200°C. The results of the work may be summarized as follows: in CO stream, carbon deposition occurred below 900°C, no carbon deposition was found above 1000°C. X-Ray analysis of the reacted sample indicated that the carbon deposition occurred with the iron was reduced. The iron reduction process and carbon deposition occurred simultaneously. The rate of carbon deposition changed with the transformation of iron oxides. The specific surface area and pore structure of reduced samples were analyzed. The specific surface area changed with the amount of carbon deposition.

scholarly journals Textural properties of synthetic clay-ferrihydrite associations

Clay Minerals ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 395-407 ◽  
Author(s):  
R. Celis ◽  
J. Cornejo ◽  
M. C. Hermosin
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mercury Porosimetry ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Fractal Approach ◽  
Adsorption Data ◽  
Synthetic Clay ◽  
Nitrogen Adsorption Data

AbstractKaolinite-ferrihydrite and montmorillonite-ferrihydrite associations were prepared following a procedure based on the Russell method for the synthesis of ferrihydrite and the texture of the clay-ferrihydrite complexes was studied using different techniques. The textural properties of kaolinite were little affected by the Fe association, showing only a slight increase in the specific surface area measured by nitrogen adsorption and a decrease in the largest pores (>10 µm), as measured by mercury porosimetry. In contrast, the nitrogen specific surface area of the montmorillonite complexes was much higher than that of the clay without Fe and the pore structure depended on the amounts of Fe in the complexes. Application of the fractal approach to nitrogen adsorption data indicated that the surface roughness (microporosity) was greater for the complexes prepared from diluted Fe(III) solutions, in agreement with the information obtained from classical interpretation of the adsorption isotherms (shape of the isotherms and t-plots).

Effect of aging and alkali activator on the porous structure of a geopolymer

2014 ◽  
Vol 47 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Prune Steins ◽  
Arnaud Poulesquen ◽  
Fabien Frizon ◽  
Olivier Diat ◽  
Jacques Jestin ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Inorganic Polymers ◽  
Porous Network ◽  
X Ray ◽  
Alkali Activator ◽  
Effects Of Aging

Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation.

Sign in / Sign up

Export Citation Format

Share Document