scholarly journals Characterisation of Activated Carbons Obtained from Rice Husk

2017 ◽  
Vol 18 (4) ◽  
pp. 299 ◽  
Author(s):  
A. Merkel ◽  
A. Satayeva ◽  
F. Cannon ◽  
C. Howell ◽  
St. Meikle ◽  
...  
Keyword(s):  
Rice Husk ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Mercury Porosimetry ◽  
Nitrogen Adsorption ◽  
Temperature Treatment ◽  
Exchange Capacity ◽  
High Temperature Treatment ◽  
Scanning Calorimetry ◽  
Ion Removal

Rice husk derived activated carbons doped with nitrogen have been studied using low temperature nitrogen adsorption, scanning electron microscopy, mercury porosimetry, thermogravimetric analysis combined with mass-spectrometry, differential scanning calorimetry and X-ray photoelectron spectroscopy. It has been shown that N-doped activated carbon produced by high temperature treatment of the starting material soaked with urea, has a significantly higher anion exchange capacity than the other samples studied, which correlates with its higher adsorption capacity towards nitrate ion removal from aqueous solutions with the initial concentration of 5 and 15 ppm.

Optimization of Production Conditions for Activated Carbons from Rice Husk by Potassium Carbonate Using Response Surface Methodology

2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Rice Husk ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Activation Temperature ◽  
Nitrogen Adsorption Isotherm

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).

The effect of acid activation and calcination of halloysite on the efficiency and selectivity of Pb(II), Cd(II), Zn(II) and As(V) uptake

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Paulina Maziarz ◽  
Jakub Matusik
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Structural Changes ◽  
Selective Adsorption ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Acid Activation ◽  
Subsequent Formation ◽  
X Ray ◽  
Mineral Structure

AbstractThe present study investigated the efficiency and mechanisms of aqueous Pb(II), Cd(II), Zn(II) and As(V) adsorption on natural (H), calcined (HC), and acid-activated halloysite (HA). The XRD and FTIR measurements indicated that the aluminosilicate framework was not affected by high-temperature treatment, in contrast to acid activation, which led to structural changes mainly in the tetrahedral sheet. The sorption of cations on H sample was low, though it was most effective for As(V). The X-ray photoelectron spectroscopy results suggested that removal of As(V) might be related to its reduction to As(III) involving oxidation of Fe(II) present in the mineral structure and/or iron minerals. The calcination enhanced halloysite sorption capacity for cations, while the As(V) sorption decreased. This was due to partial dehydroxylation and the subsequent formation of additional active sites. The acid treatment induced selective adsorption of Pb(II).

scholarly journals Synthesis of biomorphaus SiC-ceramics

2007 ◽  
Vol 61 (2) ◽  
pp. 75-78
Author(s):  
Adela Egelja ◽  
Jelena Gulicovski ◽  
Aleksandar Devecerski ◽  
Snezana Boskovic ◽  
Branko Matovic
Keyword(s):  
Photoelectron Spectroscopy ◽  
Abies Alba ◽  
Microstructural Characterization ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Sic Ceramics ◽  
Silica Source ◽  
Porous Sic ◽  
Highly Porous

The carbothermal reduction processing of partially mineralized fir (Abies alba) samples was used to obtain highly-porous SiC ceramics with cellular structure. The infiltration of TEOS (tetraetilortosilikat, Si(OC2H5)4) as a silica source, was conducted in order to carry out the mineralization process. Synthesis of the SiC was achieved with a C/SiO2 replica annealing at 1723 K in Ar atmosphere. The obtained samples were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The experimental results revealed that the hierarchical bimorphous wood structure was preserved even after high-temperature treatment. Microstructural characterization of the ceramics revealed the presence of the P-SiC phase and traces of the a-SiC phase.

scholarly journals Sustainable Carbon-Based Materials as Heterogeneous Catalysts in Solvent-Free Acetylation Reactions

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 40 ◽  
Author(s):  
Ignacio M. López-Coca ◽  
Silvia Izquierdo ◽  
Guadalupe Silvero ◽  
Carlos J. Durán-Valle
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Heterogeneous Catalysts ◽  
Activated Carbons ◽  
Nitrogen Adsorption ◽  
Solvent Free ◽  
Point Of Zero Charge ◽  
Organic Analysis ◽  
Catalytic Material

The catalytic activity of six different carbons was tested in the solvent-free acetylation reaction of alcohols, phenols, and monosaccharides with acetic anhydride. Three commercial carbons—a basic activated carbon M (Merck KGaA), a moderately basic carbon gel X (Xerolutions S.L.), and an activated carbon N (Norit Netherland B.V.)—were studied. From these commercial carbons, three acidic activated carbons—M-S, X-S, and N-S—were obtained by treatment with sulfuric acid. All six carbons were characterized by means of nitrogen adsorption capacity, porosimetry, elemental organic analysis, X-ray photoelectron spectroscopy (XPS), and point of zero charge (PZC) determination. The experiments carried out showed good catalytic activity, the magnitude of which depended on the type of carbon used. The best catalyst was X-S, which combined high acidity with the largest mesoporous volume. Second in line was the commercial carbon M, which was the most basic. The protocol reported herein encompasses several of the characteristics related to the sustainability of chemical processes, such as the innocuous nature and the affordable cost of the catalytic material, the absence of reaction solvent, and the ease of reaction work-up.

scholarly journals Influence of Conditioning Temperature on Defects in the Double Al2O3/ZnO Layer Deposited by the ALD Method

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1038
Author(s):  
Katarzyna Gawlińska-Nęcek ◽  
Mateusz Wlazło ◽  
Robert Socha ◽  
Ireneusz Stefaniuk ◽  
Łukasz Major ◽  
...  
Keyword(s):  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Atomic Layer ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Defect States ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Conditioning Temperature ◽  
Defects Analysis

In this work, we present the results of defects analysis concerning ZnO and Al2O3 layers deposited by atomic layer deposition (ALD) technique. The analysis was performed by the X-band electron paramagnetic resonance (EPR) spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods. The layers were either tested as-deposited or after 30 min heating at 300 °C and 450 °C in Ar atmosphere. TEM and XPS investigations revealed amorphous nature and non-stoichiometry of aluminum oxide even after additional high-temperature treatment. EPR confirmed high number of defect states in Al2O3. For ZnO, we found the as-deposited layer shows ultrafine grains that start to grow when high temperature is applied and that their crystallinity is also improved, resulting in good agreement with XPS results which indicated lower number of defects on the layer surface.

scholarly journals Highly Porous Expanded Graphite: Thermal Shock vs. Programmable Heating

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7687
Author(s):  
Alexander G. Bannov ◽  
Arina V. Ukhina ◽  
Evgenii A. Maksimovskii ◽  
Igor Yu. Prosanov ◽  
Artyom A. Shestakov ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Photoelectron Spectroscopy ◽  
Textural Properties ◽  
Expanded Graphite ◽  
Nitrogen Adsorption ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Constant Rate ◽  
Disorder Degree ◽  
Highly Porous

Highly porous expanded graphite was synthesized by the programmable heating technique using heating with a constant rate (20 °C/min) from room temperature to 400–700 °C. The samples obtained were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy, thermogravimetry, and differential scanning calorimetry. A comparison between programmable heating and thermal shock as methods of producing expanded graphite showed efficiency of the first one at a temperature 400 °C, and the surface area reached 699 and 184 m2/g, respectively. The proposed technique made it possible to obtain a relatively higher yield of expanded graphite (78–90%) from intercalated graphite. The experiments showed the advantages of programmable heating in terms of its flexibility and the possibility to manage the textural properties, yield, disorder degree, and bulk density of expanded graphite.

Application of Carbons Produced from Rice Husk in the Process of Capacitive Deionization

2020 ◽  
Vol 22 (4) ◽  
pp. 277
Author(s):  
V. Pavlenko ◽  
Zh. Supiyeva
Keyword(s):  
Rice Husk ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Nitrogen Adsorption ◽  
Electrochemical Cells ◽  
Capacitive Deionization ◽  
Porous Carbons ◽  
Adsorption Analysis ◽  
Main Components ◽  
Nanoporous Carbon Materials

Nanoporous carbon materials are well recognized as the main components of electrodes in capacitive deionization. Herein, the activated carbons were produced based on rice husk which is an abundant waste material in southern regions of Kazakhstan. The resulting carbons were characterized electrochemically by comparing their performance with well-known brands of commercial porous carbons (i.e. Norit DLC Super 30, Kuraray YP 50F). The features of carbon/ carbon electrochemical cells were analyzed using the means of galvanostatic cycling with potential limitation and cyclic voltammetry. Whilst the surface morphology and elemental composition of carbons were observed using scanning electron microscopy combined with energy dispersive X-ray spectroscopy. Using the method of low-temperature nitrogen adsorption it has been established that the specific surface of home-made carbon produced based on rice husk is equal to 2290 m2g-1. The salt adsorption analysis has been performed using different concentrations of inlet solutions of sodium chloride. Our study has shown that the manufacturing and application of activated carbons based on rice husk can be highly efficient because the resulting electrode materials exhibit a high electrosorption capacity of 20.02 mg g-1, which exceeds similar values obtained in the case of application of commercial porous carbons.

scholarly journals XPS Study of Mechanically Activated YBa2Cu3O6+δand NdBa2Cu3O6+δ

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
A. V. Fetisov ◽  
G. A. Kozhina ◽  
S. Kh. Estemirova ◽  
V. B. Fetisov ◽  
V. Ya. Mitrofanov ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Photoelectron Spectroscopy ◽  
Temperature Treatment ◽  
Impurity Phase ◽  
Chemical Degradation ◽  
Partial Substitution ◽  
High Temperature Treatment ◽  
Complete Disappearance ◽  
Superconducting Transition ◽  
The Impact

Oxides RBa2Cu3O6+δ(R=Y, Nd) subjected to mechanical activation in AGO-2 mill have been studied by X-ray photoelectron spectroscopy (XPS), thermal analysis, and magnetometry. It has been shown that mechanoactivation accelerates chemical degradation under the impact of H2O and CO2in YBa2Cu3O6+δsamples. Degradation occurs in the standard way. Investigation of mechanically activated NdBa2Cu3O6+δhas revealed other results. It has been suggested that CO2can diffuse into its structure more freely than in YBa2Cu3O6+δ; as a result, carbonization may proceed directly in the volume of NdBa2Cu3O6+δand independently of the hydrolysis process. In addition, the mechanism of interaction between the oxide and water is not active and not “traditional” for the homologous series REBa2Cu3O6+δ(where RE = rare earth and Y)—the characteristic “color” phase (Nd2BaCuO5) is not formed during hydrolysis. It is known that high-temperature treatment of NdBa2Cu3O6+δoxide results in partial substitution of cations Ba by Nd; which is accompanied by decrease in the superconducting transition temperature and formation of the impurity phase Ba2Cu3O5+y. According to our data, mechanical activation of the resulting solid solution Nd1+xBa2−xCu3O6+δunexpectedly has led to the reverse redistribution of cations, which has been manifested in the complete disappearance of the impurity phase and increase inTc.

scholarly journals Effectivity of Indonesian Rice Husk as an Adsorbent for Removing Congo Red from Aqueous Solutions

2021 ◽  
Vol 19 (4) ◽  
pp. 255-265
Author(s):  
Neza Rahayu Paapla ◽  
◽  
Normah Normah ◽  
Tarmizi Taher ◽  
Risfidian Mohadi ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Surface Area ◽  
Rice Husk ◽  
Congo Red ◽  
Freundlich Isotherm ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Order Kinetic ◽  
Isotherm Equation ◽  
Specific Analysis

Indonesian rice husk biochar (RH-BC) was prepared by pyrolysis method at 500°C and characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, surface-area-specific analysis by Brunauer-Emmett-Teller, and scanning electron microscopy. The RH-BC were used as adsorbents for enhancing the adsorption of Congo red compared to pristine rice husk (RH) in aqueous solutions. The results of characterization through surface-area-specific analysis showed the surface area of RH-BC (72.25 m2/g) was ten times higher than RH (7.08 m2/g) owing to high-temperature treatment. The results of the adsorption study showed that the RH and RH-BC followed the pseudo-second-order kinetic model and the Freundlich isotherm equation with maximum adsorption capacities of 85.470 mg/g and 72.993 mg/g for the RH-BC and RH, respectively. The thermodynamic parameters of adsorption indicated spontaneous and endothermic processes. The reusability of the adsorbents (RH and RH-BC) showed that they are potentially suitable for extracting Congo red from aqueous solution up to three adsorption-desorption cycles. Their performance sharply decreases after the fourth and fifth cycles.

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