Synthesis and Application of CaCO3 ontained Mesoporous Silicas
Date Issued
2008
Date
2008
Author(s)
Chen, Po-Chng
Abstract
Organo-functionalized ordered mesoporous silicas were synthesized by co-condensation of tetraethylorthosilicate (TEOS) and diethyl 2-(triethoxysilyl)ethylphosphonate or 3-cyanopropyltriethoxysilane in the presence of the di-block copolymer EO45-b-MAx (x = 45、65、90) as the surfactant. Upon extraction, the phosphonate group and cyano group were transformed into phosphonic acid and carboxylic acid respectively via a simple hydrolysis step. The morphology of these materials varies from hexagonal to cubic to disorder according to the chain length of MA. Characterization of these porous silicas were performed by powder x-ray diffraction(XRD), infrared spectrum(IR), transmission electron microscopy (TEM), solid-state NMR spectroscopy, and nitrogen adsorption/desorption studies (BET). In order to deposit CaCO3 into the mesoporous channel, Organo group modified materials were first treated with adequate amounts of CaCl2 allowing the exchange of Ca2+ ions onto the surface, which were subsequently reacted with NaHCO3. Upon precipitation, the CaCO3 was deposited onto the surface of materials. This CaCO3 deposited silicas appeared to be a good absorbent for Cu(II) and the intake amount of ions reached to 3 mmole per gram of silica. Various CaCO3 deposited materials including Mesoporous spheres(MS),silica nanoparticles(Si-NP), as well as in situ incorporation of calcium ion were also prepared for comparison.
Subjects
mesoporous
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95223085-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):864574681c7495f53d542d7a1d351e54