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Resíduos agroindustriais como fonte de sílica para a produção de nanopartículas de sílica
| Content Provider | Semantic Scholar |
|---|---|
| Author | Correia, E. |
| Copyright Year | 2015 |
| Abstract | The agro-industry wastes are byproducts resultant from the procedure of energetic crops (biomass). Their incineration provides a solid waste named ashes, which can be thrown away in disposals because of their low added value. An incorrect management of these wastes could bring serious questions about human health and environment issues. A possible solution for this problem is an encouragement to a sustainable and rational environment recovery of these wastes. A cooperation between chemistry of materials and nanotechnology are an important contribute to innovation and development of new methods and sustainable products of agro-industry wastes and byproducts that can eventually compete in the market. The rice husk is an example of cheap, abundant and biodegradable agro-industry waste that is rich in silica, its inorganic component majority. The purpose of this work was to develop simple methodologies to obtain added value in the synthesis of silica nanoparticles through rice husk. Initially, silica recovery was performed using two methodologies. The first one consisted in acid washing followed by thermal treatment in air and the second one consisted in using sol-gel method. The characterization achieved by Fourier transform infrared spectroscopy by attenuated total reflectance (FTIR-ATR), Scanning electron microscopy and energy dispersive spectrometry (SEM-EDS) and nitrogen adsorption-desorption at -196 °C allowed to confirm the presence of silica nanoparticles, and possessed specific areas between 30-244 m/g, pore volume between 0.120-0.349 cm/g and a predominantly mesostructure with an average diameter between ~4.6-6.1 nm. Another approach was followed to modify the textural properties of the silica nanoparticles using the cationic surfactant hexadecyltrimethylammonium chloride (CTAC). From the FTIR-ATR and thermogravimetric analysis (TGA) it was verified the complete removal of surfactant; SEM-EDS and nitrogen adsorption-desorption confirmed the slightly change in the textural properties of the silica nanoparticles leading to specific surface area of 198-497 m/g, pore volume from 0.268 to 0.497 cm/g and an average pore diameter of approximately 3.5-3.8 nm. Furthermore, functionalization of silica nanoparticles with fluoroalkyl organosilane (F13TES) through post-grafting e co-condensation methods, allowed the introduction of hydro/oleophobicity properties. The confirmation of surface chemistry modification by F13TES was achieved by FTIR-ATR and TGA. The hydro/oleophobicity properties were evaluated by contact angle measurements. The obtained silica materials revealed FCUP ix Resíduos agroindustriais como fonte de sílica para a produção de nanopartículas de sílica almost superhydrofobicity (~127°) and almost oleophobicity (~77°) properties, and one of them showed superhydrofobicity (>150°). |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://sigarra.up.pt/icbas/pt/pub_geral.show_file?pi_gdoc_id=73739 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
