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- Idris, Alamin, et al.
(författare)
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Investigation on particle properties and extent of functionalization of silica nanoparticles
- 2020
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 506
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of the extent of functionalization on silica nanoparticle surface is crucial in a variety of applications. This work aims to evaluate particle properties and extent of functionalization on silica nanoparticles synthesized under acidic and basic conditions via co-condensation of tetraethyl orthosilicate with 3-aminopropyltrimethoxysilane in the sol-gel process. The silica nanoparticles properties were analyzed via field emission scanning electron microscope, transmission electron microscopy, dynamic light scattering, and Brunauer-Emmett-Teller methods; whereas, the extent of functionalization was evaluated using Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, and thermogravimetric analyzer. Results showed that the functionalized silica nanoparticles have a lower tendency to agglomerate and highly monodispersed as compared to unfunctionalized. The surface areas of acid and base-catalyzed nanoparticles were obtained as 618.8 and 514.7 m2/g, respectively. FTIR spectra, XPS scans, and TGA curves confirmed the presence of alkyl and amine functional groups on the functionalized surfaces. The extent of functionalization (N/Si) was obtained as 0.296 and 0.196, and the percentages of functional groups attached on the surface were found to be 6.80 and 5.92% for acid and base-catalyzed nanoparticles, respectively. The overall results suggest that acidic catalysis is a better approach for the synthesis of surface-modified or organofunctionalized silica nanoparticles.
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| 2. |
- Khan, Amir Sada, et al.
(författare)
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Efficient Conversion of Lignocellulosic Biomass to Levulinic Acid Using Acidic Ionic Liquids
- 2018
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 181, s. 208-214
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Tidskriftsartikel (refereegranskat)abstract
- In the present research work, dicationic ionic liquids, containing 1,1-Bis(3-methylimidazolium-1-yl) butylene ([C4(Mim)2]) cation with counter anions [(2HSO4)(H2SO4)0], [(2HSO4)(H2SO4)2] and [(2HSO4)(H2SO4)4] were synthesised. ILs structures were confirmed using 1H NMR spectroscopy. Thermal stability, Hammett acidity, density and viscosity of ILs were determined. Various types of lignocellulosic biomass such as rubber wood, palm oil frond, bamboo and rice husk were converted into LA. Among the synthesized ionic liquids, [C4(Mim)2][(2HSO4)(H2SO4)4] showed higher % yield of LA up to 47.52 from bamboo biomass at 100 °C for 60 min, which is the better yield at low temperature and short time compared to previous reports. Surface morphology, surface functional groups and thermal stability of bamboo before and after conversion into LA were studied using SEM, FTIR and TGA analysis, respectively. This one-pot production of levulinic acid from agro-waste will open new opportunity for the conversion of sustainable biomass resources into valuable chemicals.
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