scholarly journals Influence of boron doping on characteristics of glucose based hydrothermal carbons

2022 ◽  
pp. 1-1
Author(s):  
Ana Kalijadis ◽  
Marina Maletic ◽  
Andjelika Bjelajac ◽  
Biljana Babic ◽  
Tamara Minovic-Arsic ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Boron Content ◽  
Structural Parameters ◽  
Surface Characteristics ◽  
Boron Doping ◽  
Surface Oxygen Groups ◽  
Boron Doped ◽  
Oxygen Groups

In this study, the influence of boron doping on structural and surface properties of carbon material synthesized by hydrothermal method was investigated, and the obtained results were compared with the previously published influence that boron has on characteristics of carbonized boron-doped hydrothermal carbons (CHTCB). Hydrothermal carbons doped with boron (HTCB), were obtained by hydrothermal synthesis of glucose solution with the different nominal concentrations of boric acid. It was found that glucose based hydrothermal carbon does not have developed porosity, and the presence of boron in their structure has insignificant influence on it. On the contrary, additional carbonization increases the specific surface area of the undoped sample, while the increase in boron content drastically decreases specific surface area. Boron doping leads to a decrease in the amount of surface oxygen groups, for both, hydrothermally synthesized and additionally carbonized material. Raman analysis showed that boron content does not affect the structural arrangement of HTCB samples, and Raman structural parameters show higher degree of disorder, compared to the CHTCB samples. Comparison of structural and surface characteristics of hydrothermal carbons and carbonized materials contributes to the study of the so far, insufficiently clarified influence that boron incorporation has on the material characteristics.

scholarly journals Photocatalytic Performance of Carbon Monolith/TiO2Composite

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Marina Maletić ◽  
Marija Vukčević ◽  
Ana Kalijadis ◽  
Zoran Laušević ◽  
Mila Laušević
Keyword(s):  
Photocatalytic Activity ◽  
Thermal Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dip Coating ◽  
Surface Oxygen ◽  
Surface Oxygen Groups ◽  
Carbon Monolith ◽  
Oxygen Groups

The new and simple approach for deposition of catalytically active TiO2coating on carbon monolith (CM) carrier was presented. CM photocatalysts were impregnated with TiO2using titanium solution and thermal treatment, and their photocatalytic activity was investigated in the process of methylene blue (MB) photodegradation. For the purpose of comparison, CM composite photocatalysts were prepared by dip-coating method, which implies binder usage. The presence of TiO2on CM carrier was confirmed by Raman spectroscopy and scanning electron microscopy. The sorption characteristics of CM and the role of adsorption in the overall process of MB removal were evaluated through amount of surface oxygen groups obtained by temperature-programmed desorption and specific surface area determined by BET method. CM has shown good adsorption properties toward MB due to high amount of surface oxygen groups and relatively high specific surface area. It was concluded that photocatalytic activity increases with CM disc thickness due to increase of MB adsorption and amount of deposited TiO2. Good photocatalytic activity achieved for samples obtained by thermal treatment is the result of better accessibility of MB solution to the TiO2particles induced by binder absence.

scholarly journals Characterization of surface oxygen groups on different carbon materials by the Boehm method and temperature programmed desorption

2011 ◽  
Vol 76 (5) ◽  
pp. 757-768 ◽  
Author(s):  
Ana Kalijadis ◽  
Marija Vukcevic ◽  
Zoran Jovanovic ◽  
Zoran Lausevic ◽  
Mila Lausevic
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Materials ◽  
Temperature Programmed Desorption ◽  
Surface Oxygen ◽  
Surface Oxygen Groups ◽  
Bet Analysis ◽  
Temperature Programmed ◽  
Oxygen Groups

The surface characteristics of different carbon materials: activated carbon, carbon felt, glassy carbon and a porous carbon monolith were investigated. The specific surface area was examined by the BET method with N2 adsorption, the amount and the type of surface oxygen groups by Boehm titration as well as by temperature-programmed desorption (TPD). By comparing the results obtained using BET analysis with those of TPD and the Boehm method, it was found that the number of surface groups was not proportional to the specific surface area. The total amount of oxygen groups, obtained by TPD, is higher than the amount obtained by Boehm?s method for porous samples. The inconsistencies between these results originate from the fact that the Boehm method is limited to the determination of acidic and basic groups, whereas TPD provides information on the total number of all surface oxygen groups. In addition, the presence of porosity could reduce the solvent-accessible surface in the Boehm method. The TPD profiles of CO evolution showed the presence of a low temperature maximum, below 650 K, which originates from CO2 reduction on the carbon material surface.

scholarly journals Structural and fractal characterization of adsorption pores of middle–high rank coal reservoirs in western Yunnan and eastern Guizhou: An experimental study of coals from the Panguan syncline and Laochang anticline

2018 ◽  
Vol 37 (1) ◽  
pp. 251-272 ◽  
Author(s):  
Junjian Zhang ◽  
Chongtao Wei ◽  
Gaoyuan Yan ◽  
Guanwen Lu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Structural Parameters ◽  
Total Pore Volume ◽  
Type A ◽  
Type B ◽  
Type C

To better understand the structural characteristic of adsorption pores (pore diameter < 100 nm) of coal reservoirs around the coalbed methane production areas of western Yunnan and eastern Guizhou, we analyzed the structural and fractal characteristics of pore size range of 0.40–2.0 nm and 2–100 nm in middle–high rank coals ( Ro,max = 0.93–3.20%) by combining low-temperature N2/CO2 adsorption tests and surface/volume fractal theory. The results show that the coal reservoirs can be divided into three categories: type A ( Ro,max < 2.15%), type B (2.15% <  Ro,max <2.50%), and type C ( Ro,max > 2.15%). The structural parameters of pores in the range from 2 to 100 nm are influenced by the degree of coal metamorphism and the compositional parameters (e.g., ash and volatile matter). The dominant diameters of the specific surface areas are 10–50 nm, 2–50 nm, and 2–10 nm, respectively. The pores in the range from <2 nm provide the largest proportion of total specific surface area (97.22%–99.96%) of the coal reservoir, and the CO2-specific surface area and CO2-total pore volume relationships show a positive linear correlation. The metamorphic degree has a much greater control on the pores (pore diameter less than 2 nm) structural parameters than those of the pore diameter ranges from 2 to 100 nm. Dv1 and Dv2 can characterize the structure of 2–100 nm adsorption pores, and Dv1 (volume heterogeneity) has a positive correlation with the pore structural parameters such as N2-specific surface area and N2-total pore volume. This parameter can be used to characterize volume heterogeneity of 2–10 nm pores. Dv2 (surface heterogeneity) showed type A > type B > type C and was mainly affected by the metamorphism degree. Ds2 can be used to characterize the pore surface heterogeneity of micropores in the range of 0.62–1.50 nm. This parameter has a good correlation with the pore parameters (CO2-total pore volume, CO2-specific surface area, and average pore size) and is expressed as type C < type B < type A. In conclusion, the heterogeneity of the micropores is less than that of the meso- and macropores (2–100 nm). Dv1, Dv2, and Ds2 can be used as effective parameters to characterize the pore structure of adsorption pores. This result can provide a theoretical basis for studying the pore structure compatibility of coal reservoirs in the region.

scholarly journals Structural parameters for X-ray micro-computed tomography (μCT) and their relationship with the breakage rate of maize varieties

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Junfeng Hou ◽  
Ying Zhang ◽  
Xiuliang Jin ◽  
Pengfei Dong ◽  
Yanan Guo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Structural Parameters ◽  
Cavity Volume ◽  
X Ray ◽  
Maize Varieties ◽  
Breakage Rate ◽  
Maize Grain ◽  
Grain Breakage

Abstract Background High grain breakage rate is the main limiting factor encountered in the mechanical harvest of maize grain. X-ray micro-computed tomography (μCT) scanning technology could be used to obtain the three-dimensional structure of maize grain. Currently, the effect of maize grain structure on the grain breakage rate, determined using X-ray μCT scanning technology, has not been reported. Therefore, the objectives of this study are: (i) to obtain the shape, geometry, and structural parameters related to the breakage rate using X-ray μCT scanning technology; (ii) to explore relationships between these parameters and grain breakage rate. Result In this study, 28 parameters were determined using X-ray μCT scanning technology. The maize breakage rate was mainly influenced by the grain specific surface area, subcutaneous cavity volume, sphericity, and density. In particular, the breakage rate was directly affected by the subcutaneous cavity volume and density. The maize variety with high density and low subcutaneous cavity volume had a low breakage rate. The specific surface area (r = 0.758*), embryo specific surface area (r = 0.927**), subcutaneous cavity volume ratio (0.581*), and subcutaneous cavity volume (0.589*) of maize grain significantly and positively correlated with breakage rate. The cavity specific surface area (− 0.628*) and grain density (− 0.934**) of maize grain significantly and negatively correlated with grain breakage rates. Grain shape (length, width, thickness, and aspect ratio) positively correlated with grain breakage rate but the correlation did not reach statistical significance. The susceptibility of grain breakage increased when kernel weight decreased (− 0.371), but the effect was not significant. Conclusions The results indicate that X-ray μCT scanning technology could be effectively used to evaluate maize grain breakage rate. X-ray μCT scanning technology provided a more precise and comprehensive acquisition method to evaluate the shape, geometry, and structure of maize grain. Thus, data gained by X-ray μCT can be used as a guideline for breeding resistant breakage maize varieties. Grain density and subcutaneous cavity volume are two of the most important factors affecting grain breakage rate. Grain density, in particular, plays a vital role in grain breakage and this parameter can be used to predict the breakage rate of maize varieties.

Preliminary Study of Activated Carbon Modified by Silica Aerogel

2013 ◽  
Vol 785-786 ◽  
pp. 749-752
Author(s):  
Ya Jun Luo ◽  
Qian Yan ◽  
Yong Chao Zhou ◽  
Deng Liang He ◽  
Xiao Li Hu
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Surface Characteristics ◽  
Carbon Composite ◽  
Adsorption Method ◽  
Preliminary Study

Activated carbon was modified with silica aerogel by the Sol-Gel. The surface characteristics and structure of activated carbon modified by the silica aerogel were characterized with N2 adsorption method, Scanning Electron Microscope and Thermal Analysis. The experiment results show that the silica aerogel can be used to modify activated carbon for the preparation of composite. SiO2 aerogel can effectively cover holes in the activated carbon, specific surface area of activated carbon composite modified by SiO2 aerogel was between activated carbon and silica aerogel. When MSiO2: MC is 1:3, specific surface area of the composite was 758.638 m2/g; When MSiO2:MC is 1:2, specific surface area of the composite was 760.38 m2/g; When MSiO2:MC is 1:1, specific surface area of the composite was 862.755 m2/g.

Boron-doped α-Ni(OH)2 nanoflowers with high specific surface area as electrochemical capacitor materials

2014 ◽  
Vol 128 ◽  
pp. 380-383 ◽  
Author(s):  
Jing-He Yang ◽  
Chao Wang ◽  
Duo Yang ◽  
Xingyun Li ◽  
Peng Shang ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrochemical Capacitor ◽  
High Specific Surface Area ◽  
Boron Doped

Study on Porous Structure and Surface Characteristics of Al-Pillared Montmorillonite

2011 ◽  
Vol 194-196 ◽  
pp. 1834-1838 ◽  
Author(s):  
Gui Fang Wang ◽  
Shao Jian Ma ◽  
Shuai Zhang ◽  
Xian Jun Lu ◽  
Wei Mo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Characteristics ◽  
Interlayer Spacing ◽  
Elemental Distribution ◽  
Volume Distribution ◽  
Pillared Montmorillonite ◽  
Pillaring Solution

Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N2 adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d(001) value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na+ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

A novel efficient boron-doped LaFeO3photocatalyst with large specific surface area for phenol degradation under simulated sunlight

CrystEngComm ◽  
2015 ◽  
Vol 17 (20) ◽  
pp. 3859-3865 ◽  
Author(s):  
Haitao Wu ◽  
Ruisheng Hu ◽  
Tingting Zhou ◽  
Chun Li ◽  
Wanwan Meng ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Phenol Degradation ◽  
Large Specific Surface Area ◽  
Simulated Sunlight ◽  
Boron Doped

A New Empirical Equation for Estimating Specific Surface Area of Supercapacitor Carbon Electrode from X-Ray Diffraction

2015 ◽  
Vol 1108 ◽  
pp. 1-7 ◽  
Author(s):  
Mohamad Deraman ◽  
Rusli Daik ◽  
Sepideh Soltaninejad ◽  
Najah Syahirah Mohd Nor ◽  
Awitdrus ◽  
...  
Keyword(s):  
Energy Storage ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Materials ◽  
Structural Parameters ◽  
Porous Electrodes ◽  
Double Layers ◽  
X Ray Diffraction ◽  
X Ray

Interest in research of supercapacitor has been in increasing trend because of high demand of supercapacitor application as energy storage device in both systems that require low and high power-energy usage. For supercapacitor using porous carbon electrodes, the energy storage mechanism involves the electrolyte ions in electrodes pores and electronic charges in electrodes to form electric double layers at the electrode-electrolyte interface without undergoes any chemical reaction. The specific surface area of porous electrodes, which affect the performance of supercapacitor, have been widely investigated by many researchers using the nitrogen adsorption-desorption measurement. However, despite its simplicity the X-ray diffraction method is rarely found being used to determine the specific surface area of porous electrodes. Therefore, in the present paper, we propose a new equation which expressed the specific surface area of electrodes as a function the electrode structural parameters obtained from the X-ray diffraction data, and duration of activation time employed during the electrode preparation. This equation is found to produce a satisfactory result and is expected to be beneficial for studying supercapacitor electrode materials.

Stability constants for silicate adsorbed to ferrihydrite

Clay Minerals ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 341-350 ◽  
Author(s):  
H. C. B. Hansen ◽  
T. P. Wetche ◽  
K. Raulund-Rasmussen ◽  
O. K. Borggaard
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Equilibrium Constants ◽  
Surface Acidity ◽  
Surface Characteristics ◽  
Complexation Constant ◽  
Diffusion Controlled ◽  
Surface Equilibrium ◽  
Optimization Routine

AbstractIntrinsic surface acidity constants (Kalintr, Ka2intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (Ksi for the complex ≡FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 M NaClO4 electrolytes and silicate adsorption experiments in 0.01 M NaNOi electrolyte (pH 3-6). The surface equilibrium constants were calculated according to the two-layer model by Dzombak ' Morel (1990). Near equilibrium between protons/hydroxyls in solution and the ferrihydrite surface was obtained within minutes while equilibration with silicate required days-weeks, both reactions probably being diffusion controlled. Applying the values for specific surface area and site densities for ferrihydrite used by Dzombak ' Morel (1990) (600 m2 g–1, 3.4 μmole m–2) the constants pKalintr = 6.93 ± 0.12, pKa2intr = 8.72 ± 0.17 and log Ksi = 3.62 were calculated by using the FITEQL optimization routine. Use of the specific surface area actually measured (269 m2 g-1) gave a poorer fit of the experimental data. Due to the slow adsorption of silicate and hence long shaking times, changes in the surface characteristics of the ferrihydrite seem to take place, probably a decrease in the concentration of surface sites. Adsorption isotherms calculated using the derived equilibrium constants showed that approximately twice the amount of silicate was adsorbed at pH 5 compared with pH 3.Infrared spectroscopy of silica adsorbed to ferrihydrite showed Si-O stretching absorption maxima in the range 940-960 cm-1. The shift of the absorption maximum to higher wavenumbers with increasing amount of silicate adsorbed is probably due to an increase in the frequency of Si-O-Si bonds between orthosilicate adsorbed at adjacent sites. Small amounts of goethite were identified in the adsorption products.

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