Study of Characteristic of Vetiver Fiber Before and after Alkaline Treatment

2010 ◽  
Vol 123-125 ◽  
pp. 1191-1194 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Nitinat Suppakarn ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Thermogravimetric Analysis ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Surface Analysis ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Before And After

In this study, untreated and alkali-treated vetiver fibers were characterized by thermogravimetric analysis, BET surface analysis, X-ray diffraction and FTIR (ATR) microspectroscopy,. It was revealed that the alkaline treatment influenced properties of vetiver fiber. By the treatment, some hemicellulose and lignin were removed, resulting in higher decomposition temperatures. In addition, the specific surface area were decreased, and crystalline structure was altered. However, no evidence of changes in surface functional groups was observed.

scholarly journals Structural Characterization of Graphene Oxide: Surface Functional Groups and Fractionated Oxidative Debris

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1180 ◽  
Author(s):  
Elvin Aliyev ◽  
Volkan Filiz ◽  
Muntazim M. Khan ◽  
Young Joo Lee ◽  
Clarissa Abetz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Functional Groups ◽  
Structural Model ◽  
Oxide Surface ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Transmission Electron

The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

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.

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

2008 ◽  
Vol 8 (12) ◽  
pp. 6445-6450
Author(s):  
F. Paraguay-Delgado ◽  
Y. Verde ◽  
E. Cizniega ◽  
J. A. Lumbreras ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

scholarly journals Influence of Activator Na2O Concentration on Residual Strengths of Alkali-Activated Slag Mortar upon Exposure to Elevated Temperatures

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1296 ◽  
Author(s):  
Tai Tran ◽  
Hyug-Moon Kwon
Keyword(s):  
Thermogravimetric Analysis ◽  
Elevated Temperatures ◽  
Silicate Liquid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Variation ◽  
Before And After ◽  
Activated Slag ◽  
Alkali Activated ◽  
Slag Weight

The mechanical strength variation of ambient cured Alkali-activated mortar (AAS) upon exposure to elevated temperatures from 200 to 1200 °C was studied in this article. Slag was activated by the combination of sodium silicate liquid (Na2SiO3) and sodium hydroxide (NaOH) with different Na2O concentrations of 4%, 6%, 8%, and 10% by slag weight. Mechanical properties comprising compressive strength, flexural strength, and tensile strength before and after exposure were measured. Thermogravimetric analysis (Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG)), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) were also used for strength alteration explanation. The results indicated that Na2O concentration influence on strength variation of AAS mortar was observed clearly at temperature range from ambient temperature to 200 °C. The melting alteration of AAS mortar after exposed to 1200 °C was highly dependent on concentrations of Na2O.

scholarly journals Bio-polishing sludge adsorbents for dye removal

2016 ◽  
Vol 18 (4) ◽  
pp. 15-21 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Norulaina Alias ◽  
Mohd. Azizi Che Yunus
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Treatment Strategies ◽  
Blue Dye ◽  
Surface Functional Groups ◽  
Adsorption Capacities ◽  
Maximum Removal

Abstract The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR) > zinc chloride-treated (SZ) > microwave-dried (SW) = potassium carbonate-treated (SK) > acid-washed (SH). The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.

Structural and morphological features of MgO powders. The key role of the preparative starting compound

1998 ◽  
Vol 13 (8) ◽  
pp. 2218-2223 ◽  
Author(s):  
S. Ardizzone ◽  
C. L. Bianchi ◽  
B. Vercelli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Starting Compound ◽  
Scanning Electron

The present paper reports data concerning magnesia samples obtained by calcination of different precursor salts at different increasing temperatures (873–1253 K). The oxides are characterized by x- ray diffraction, scanning electron microscopy, and N2 adsorption at subcritical temperatures. The samples appear to be composed, at any temperature, of pure periclase with a degree of crystallinity which increases with the temperature of calcination. Morphologically, the products have the shape either of lamellas or of cubes of variable dimensions, depending on the nature and route of preparation of the precursor salts. The variation of the specific surface area and the degree of porosity with the nature of the precursors and the temperature is discussed.

Study of Gamma Alumina Synthesis – Analysis of the Specific Surface Area

2014 ◽  
Vol 87 ◽  
pp. 54-60 ◽  
Author(s):  
A.H. Munhoz ◽  
H. de Paiva ◽  
L. Figueiredo de Miranda ◽  
E.C. de Oliveira ◽  
Raphael Cons Andrades ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ageing Time ◽  
Precursor Solution ◽  
Specific Area ◽  
Gamma Alumina ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dta And Tg

Different samples of pseudoboehmite (PB) were synthesized through the sol-gel process, using aluminum nitrate as precursor. The influence of variables on the synthesis and calcinations of the PB on the specific area of the obtained gamma-Alumina were studied. The variables were the ageing temperature (25 and 130o C), addition or not of polyvinyl alcohol to the precursor solution and the ageing time of the PB. The pH adjustment of the precursor solution was made by using ammonium carbonate. The products, which were obtained on different conditions, were then characterized by x-ray diffraction, specific area measurements through the BET process, and by thermal analysis (DTA and TG). After characterization, the synthesis products were calcined at 500°C; during this process the gamma-Alumina transformation was observed. The calcination products were characterized by the same methods (x-ray diffraction, BET, DTA and TG) and the desorption-absorption curves were obtained as well, in order to measure the pore volume of the samples. Finally, the results were analyzed through an experimental factorial planning, which showed that high specific surface area gamma-Al2O3 (around 330m²/g) can be obtained through this process.

scholarly journals Preparation and photocatalytic activity of the layered titanates

2010 ◽  
Vol 4 (2) ◽  
pp. 69-73 ◽  
Author(s):  
Marija Milanovic ◽  
Ivan Stijepovic ◽  
Ljubica Nikolic
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Bet Method ◽  
Ft Ir

Titanate structures were synthesized in highly alkaline solution using hydrothermal procedure. As-prepared powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). A specific surface area of the powders was measured by BET method. Results confirmed formation of layered trititanates, already after one hour of hydrothermal synthesis. To examine the photocatalytic activity of the as-prepared layered titanates, methylene blue (MB) was employed as a target compound in response to visible light at ambient temperature. It was observed that the specific surface area, size distribution and crystallinity are important factors to get high photocatalytic activity for the decomposition of MB. .

scholarly journals W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 836
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Alessia Amodio ◽  
Mauro Mazzocchi ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Gas Sensing ◽  
Molar Fraction ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

scholarly journals Chemical and mineralogical changes in a Brazilian Rhodic Paleudult under different land use and managements

2014 ◽  
Vol 38 (4) ◽  
pp. 1304-1314 ◽  
Author(s):  
Jessé Rodrigo Fink ◽  
Alberto Vasconcellos Inda ◽  
Jaime Antonio de Almeida ◽  
Carlos Alberto Bissani ◽  
Elvio Giasson ◽  
...  
Keyword(s):  
Land Use ◽  
Specific Surface ◽  
Surface Area ◽  
Clay Minerals ◽  
Soil Solution ◽  
Chemical Elements ◽  
Poultry Litter ◽  
X Ray Diffraction ◽  
Organic C ◽  
X Ray

Changes in land use and management can affect the dynamic equilibrium of soil systems and induce chemical and mineralogical alterations. This study was based on two long-term experiments (10 and 27 years) to evaluate soil used for no-tillage maize cultivation, with and without poultry litter application (NTPL and NTM), and with grazed native pasture fertilized with cattle droppings (GrP), on the chemical and mineralogical characteristics of a Rhodic Paleudult in Southern Brazil, in comparison with the same soil under native grassland (NGr). In the four treatments, soil was sampled from the 0.0-2.5 and 2.5-5.0 cm layers. In the air-dried fine soil (ADFS) fraction (∅ < 2 mm), chemical characteristics of solid and liquid phases and the specific surface area (SSA) were evaluated. The clay fraction (∅ < 0.002 mm) in the 0.0-2.5 cm layer was analyzed by X-ray diffraction (XRD) after treatments for identification and characterization of 2:1 clay minerals. Animal waste application increased the total organic C concentration (COT) and specific surface area (SSA) in the 0.0-2.5 cm layer. In comparison to NGr, poultry litter application (NTPL) increased the concentrations of Ca and CECpH7, while cattle droppings (GrP) increased the P and K concentrations. In the soil solution, the concentration of dissolved organic C was positively related with COT levels. With regard to NGr, the soil use with crops (NTM and NTPL) had practically no effect on the chemical elements in solution. On the other hand, the concentrations of most chemical elements in solution were higher in GrP, especially of Fe, Al and Si. The Fe and Al concentrations in the soil iron oxides were lower, indicating reductive/complexive dissolution of crystalline forms. The X-ray diffraction (XRD) patterns of clay in the GrP environment showed a decrease in intensity and reflection area of the 2:1 clay minerals. This fact, along with the intensified Al and Si activity in soil solution indicate dissolution of clay minerals in soil under cattle-grazed pasture fertilized with animal droppings.

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