scholarly journals Synthesis of high surface area magnesia by using walnut shell as a template

2019 ◽  
Vol 8 (1) ◽  
pp. 199-206 ◽  
Author(s):  
Asghar Zamani ◽  
Ahmad Poursattar Marjani ◽  
Mojtaba Abedi Mehmandar
Keyword(s):  
Surface Area ◽  
Magnesium Oxide ◽  
Aerobic Oxidation ◽  
High Surface ◽  
High Surface Area ◽  
Magnesium Nitrate ◽  
Walnut Shell ◽  
Solid Catalyst ◽  
Loaded Material ◽  
Adsorption Desorption

Abstract In the present study, high surface area amorphous magnesia was synthesized using walnut shell as a template. This green, simple and useful synthetic protocol was based on the precipitation of magnesium nitrate on biomass in an aqueous phase, followed by calcination. Materials were characterized using X-ray diffraction, scanning electron microscopy (SEM) and N2 adsorption/desorption porosimetry, and the results exhibited high surface area for magnesium oxide. Furthermore, the pore size and surface area of these mesoporous materials can be adjusted by varying the biomass/magnesium nitrate ratio. In addition, magnesium oxide was studied as the support of palladium nanoparticles for the aerobic oxidation of alcohols. We have found out that the resulting Pd-loaded material acts as an effective catalytic system for the aerobic oxidation of benzylic and aliphatic alcohols. The catalyst can be recovered and reused three times without loss of activity. Also, to test the catalytic activity of magnesium oxides as a solid catalyst, we selected Meerwein-Ponndorf-Verley reduction of cyclohexanone with 2-propanol over different magnesium oxides.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

scholarly journals Synthesis and characterization of mesoporous materials with SBA and MCM structure types

Cerâmica ◽  
2019 ◽  
Vol 65 (376) ◽  
pp. 585-591
Author(s):  
R. A. Sacramento ◽  
O. M. S. Cysneiros ◽  
B. J. B. Silva ◽  
A. O. S. Silva
Keyword(s):  
Surface Area ◽  
Mesoporous Materials ◽  
High Surface ◽  
High Surface Area ◽  
Textural Properties ◽  
N2 Adsorption ◽  
Structure Directing Agent ◽  
Type Iv ◽  
Xrd Patterns ◽  
Adsorption Desorption

Abstract Mesoporous materials are promising structures for application in catalysis and adsorption due to high surface area and large pore size. Mesoporous materials were synthesized by the hydrothermal method with novel surfactants, distinct from those observed in the literature, in order to carry out a study of its structure and to obtain materials with better textural properties. The structures synthesized with the surfactants Igepal CO630 and Brij O20 presented the best results of specific surface area, 1074 and 1075 m2.g-1, respectively. The obtained materials were characterized by XRD, TG/DTG, N2 adsorption-desorption, and FTIR techniques. XRD patterns indicated that the highly ordered mesoporous silica structures, such as MCM-41 and MCM-48, using CTMABr as the structure-directing agent and the SBA-15, SBA-16 and other SBA structures using different block copolymers were obtained. Through N2 adsorption-desorption isotherms, it was observed type IV isotherms, attributed to mesoporous materials. The FTIR spectra presented similar behaviors with characteristic vibrational bands of MCM and SBA type materials.

Hierarchical flowerlike magnesium oxide hollow spheres with extremely high surface area for adsorption and catalysis

2016 ◽  
Vol 4 (2) ◽  
pp. 400-406 ◽  
Author(s):  
Shuliang Yang ◽  
Peipei Huang ◽  
Li Peng ◽  
Changyan Cao ◽  
Yanan Zhu ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Surface Area ◽  
Magnesium Oxide ◽  
Heavy Metal Ions ◽  
Catalytic Properties ◽  
Condensation Reaction ◽  
High Surface ◽  
Hollow Spheres ◽  
High Surface Area ◽  
Adsorption Properties

3D hierarchical flowerlike MgO hollow spheres with extremely high surface area showed excellent adsorption properties for heavy metal ions and catalytic properties for the Claisen–Schmidt condensation reaction.

Nanocrystalline ultra high surface area magnesium oxide as a selective base catalyst

2001 ◽  
Vol 44 (8-9) ◽  
pp. 1663-1666 ◽  
Author(s):  
Ryan Richards ◽  
Ravichandra S Mulukutla ◽  
Ilya Mishakov ◽  
Vladimir Chesnokov ◽  
Alexander Volodin ◽  
...  
Keyword(s):  
Surface Area ◽  
Magnesium Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Base Catalyst

A porous Brønsted superacid as an efficient and durable solid catalyst

2018 ◽  
Vol 6 (38) ◽  
pp. 18712-18719 ◽  
Author(s):  
Qi Sun ◽  
Kewei Hu ◽  
Kunyue Leng ◽  
Xianfeng Yi ◽  
Briana Aguila ◽  
...  
Keyword(s):  
Surface Area ◽  
Active Sites ◽  
High Surface ◽  
High Surface Area ◽  
Solid Catalyst ◽  
Chemical Transformations ◽  
Catalytic Activities ◽  
Industrial Chemical

A porous superacid material with a high surface area and abundant accessible active sites is rationally designed, showing outstanding catalytic activities and durability in industrial chemical transformations.

Evaluation of Iodine-Adsorption on Magnesium Compounds Toward Fixing of Radioactive Iodine

2014 ◽  
Vol 617 ◽  
pp. 201-204
Author(s):  
Naoya Yoshida ◽  
Ryo Kadokura ◽  
Kunio Watanabe ◽  
Keiji Awata ◽  
Akio Ishida ◽  
...  
Keyword(s):  
Surface Area ◽  
Magnesium Oxide ◽  
Radioactive Iodine ◽  
High Surface ◽  
High Surface Area ◽  
Adsorption Method ◽  
Magnesium Compounds ◽  
Iodine Adsorption ◽  
Magnesium Compound

We studied an adsorption method as a technique of collection, and a vitrification method of iodine toward safekeeping. In this study, iodine-adsorptions on magnesium compounds were evaluated, and fixation of iodine into glass was tried. As a result, it was revealed that 1 g of magnesium oxide with high surface area successfully adsorbed 2.23 g of iodine. Iodine-adsorbed magnesium compound was tried to be vitrified with MgO-P2O5 glass.

Synthesis of high surface area boehmite and alumina by using walnut shell as template

2019 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Asghar Zamani ◽  
Ahmad Poursattar Marjani ◽  
Nasim Abdollahpour
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Walnut Shell
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