High surface area thermally stabilized porous iron oxide/silica nanocomposites via a formamide modified sol–gel process

2008 ◽  
Vol 254 (13) ◽  
pp. 3767-3773 ◽  
Author(s):  
Kamal M.S. Khalil ◽  
Salah A. Makhlouf
2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih

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.


2013 ◽  
Vol 37 (1) ◽  
pp. 245-249 ◽  
Author(s):  
Fernando Hung-Low ◽  
Geneva R. Peterson ◽  
Marauo Davis ◽  
Louisa J. Hope-Weeks

2006 ◽  
Vol 13 (3-4) ◽  
pp. 251-258 ◽  
Author(s):  
Chaochin Su ◽  
Kuei-Fen Lin ◽  
Ya-Hui Lin ◽  
Bor-Hou You

RSC Advances ◽  
2014 ◽  
Vol 4 (62) ◽  
pp. 32934-32940 ◽  
Author(s):  
Hui Yang ◽  
Wenjun Zhu ◽  
Sai Sun ◽  
Xingzhong Guo

Monolithic titania (TiO2) aerogels with high surface area were successfully synthesized by the sol–gel process combined surface modification, followed by ambient pressure drying.


2010 ◽  
Vol 148-149 ◽  
pp. 1629-1633
Author(s):  
Dong Hua Wang ◽  
Xin Fu

High surface area porous silicon carbide was synthesized by a modified sol-gel method. In the sol-gel method, furfuryl alcohol and tetraethoxysilane were used respectively as carbon and silicon precursors for preparing a carbonaceous silica xerogel. Polymethylhydrosiloxane (PMHS) was employed as pore-adjusting agent in the sol-gel process. SiC was obtained by the carbothermal reduction of the carbonaceous silica xerogel at 1300 oC in argon flow and then purified by removing excess silica, carbon and other impurities. XRD、FTIR、SEM、HRTEM and BET were used to characterize the SiC samples. The results show that the SiC products are found to have high specific surface area of 135 m2 /g. PMHS has important effect on the surface area, pore volume of the SiC products. It is therefore suggested that PMHS plays the role of structure-directing agent that enhances the production of mesoporous pores in the SiC products.


2015 ◽  
Vol 830-831 ◽  
pp. 476-479
Author(s):  
Srinivasan Nagapriya ◽  
M.R. Ajith ◽  
H. Sreemoolanadhan ◽  
Mariamma Mathew ◽  
S.C. Sharma

Silica aerogels have been prepared through sol-gel process by polymerization of TEOS in the presence of NH4F and NH4OH as catalysts. The solvent present in the gel is replaced by ethanol followed by a non-polar solvent such as n-hexane prior to solvent modification step. Gels are made hydrophobic by treating them with HMDZ to prevent rupture during drying, which has been confirmed by FTIR. Gels are then washed and dried carefully in a PID controlled oven at atmospheric pressure. The ageing duration and solvent exchange combinations are optimized to yield crack-free gels prior to drying. Aerogels are characterized for density, specific surface area, pore volume, pore size, thermal stability and contact angle. Hydrophobic, high surface area (570 m2/g), low density (0.07 g/cm3) silica aerogels are synthesized by using optimized mole ratio of precursors and catalysts. Silica aerogel granules (1-3 mm) as well as monoliths (Ф~35 mm) could be produced through ambient pressure drying of gels.


2014 ◽  
Author(s):  
S. Wahyuningsih ◽  
A. H. Ramelan ◽  
G. Juliana ◽  
A. R. Khoirunisa ◽  
S. B. Rahardjo ◽  
...  

2011 ◽  
Vol 194-196 ◽  
pp. 562-565
Author(s):  
Dong Hua Wang ◽  
Xin Fu

High surface area porous silicon carbide was synthesized by employing polymethylhydrosiloxane (PMHS) as soft template in the sol-gel process. In the sol-gel method, furfuryl alcohol and tetraethoxysilane were used respectively as carbon and silicon precursors for preparing a carbonaceous silica xerogel. PMHS was employed as pore-adjusting agent in the sol-gel process. The purified SiC sample was characterized by XRD、FTIR、SEM、HRTEM and BET. The results show that the SiC products are found to have high specific surface area of 125 m2 /g and an average pore diameter of about 17 nm. PMHS has important effect on the surface area of the SiC products.


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