Study of the thermal treatment of SiO<sub>2</sub>aggregate

Tahiri, N.; Khouchaf, L.; Elaatmani, M.; Louarn, G.; Zegzouti, Abdelouahad; Daoud, Mohamed

doi:10.1088/1757-899x/62/1/012002

Cited by 28 publications

(19 citation statements)

References 25 publications

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“…Thermal treatment causes displacement of the main peak at about 1100 cm −1 “Peak 4” to a higher wavenumber: 1059–1081, 1047–1078 and 1068–1079 cm −1 for SiNP10:YEu , SiNP50:YEu and SiNP100:YEu , respectively. This shift is explained by a decrease in the structural disorder of the amorphous silica with a variation of the bridging Si-O-Si bonding angle and a decreasing of the defects [ 18 , 19 , 20 ]. This decrease in disorder was also observed by DRX.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, thermal treatment is usually applied to remove unwanted species. This step may alter the structure of the silica, such as favoring SiO 2 condensation in a three-dimensional network leading to a more organized structure after decreasing the concentration of silanol groups (Si-OH) [17][18][19][20]. The study of the influence of thermal treatment at 900 • C for 5 h on their different properties is presented and discussed.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

et al. 2021

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Europium (Eu)-doped silica nanoparticles have attracted great interest for different applications, in particular in biomedicine as biosensors or for tissue regeneration. Sol-gel is the most common process used to prepare those particles, with size varying from tens to hundreds of nanometers. In this article, we focus our attention on the comparison between two commonly used sol-gel derived methods: reverse microemulsion (for particles smaller than 100 nm) and Stöber method (for particles larger than 100 nm). Europium concentration was varied between 0.2 and 1 mol%, and the nanoparticle diameters were 10, 50 and 100 nm. The link between the local environment of europium ions and their optical properties was investigated and discussed. Using Transmission Electron Microscopy, nitrogen sorption, X-ray diffraction, Fourier-Transform Infra-Red and pulsed doubled Nd:YAG laser, we confirmed that fluorescence lifetime was improved by thermal treatment at 900 °C due to the elimination of aqueous environment and modification of structure disorder. The size of nanoparticles, the amount of europium and the thermal treatment of obtained materials influence the emission spectra and the decay curves of Eu3+.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

et al. 2021

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“…A peak at 1178 cm -1 , attenuated to the Si-O-Si asymmetric vibrational frequency, confirms the presence of silica skeleton in Turkish perlite. After thermal activation, this peak gets shifted to 1227 cm -1 which is a common phenomenon in amorphous silica samples [60]. An intense peak around 1630 cm -1 in Turkish perlite, characteristic of bending mode (δO-H) of water molecule [61,62] again highly decreased in TAP.…”

Section: Characterization Of Catalystsmentioning

confidence: 91%

Turkish perlite supported nickel oxide as the heterogeneous acid catalyst for a series of Claisen–Schmidt condensation reactions

Malpani¹,

Goyal

Katara

et al. 2021

Turk J Chem

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Potentially active and eco-friendly solid acid catalysts have been synthesized by loading different weight percentages (10, 15, and 50) of nickel oxide on thermally activated Turkish perlite through the deposition-precipitation method. Structural features of prepared catalysts were analyzed using BET surface area analysis, X-ray diffraction, SEM, SEM-EDX, TEM, FT-IR, pyridine adsorbed FT-IR, UV-Vis DRS, and TGA techniques. Pyridine adsorbed FT-IR analysis confirmed the presence of the optimum amount of Bronsted acidic sites in a catalyst having 15 wt. % loading of nickel oxide which was tested for catalyzing a series of Claisen-Schmidt condensation of cyclohexanone and aromatic aldehydes to produce good isolated yield (90-93%) of 2,6bis(substituted benzylidene)cyclohexanones, significantly used in anti-tumor and cytotoxic activities. The high catalytic efficiency of the chosen catalyst remains almost 2 intact up to six reaction cycles. On higher wt. % loading of nickel oxide, crystallite size increases along with agglomeration of larger nickel oxide particles on catalyst surface resulting in pore blockage and poor catalytic activity. Loading of NiO on the surface of thermally activated Turkish perlite was confirmed by SEM-EDX analysis and TEM observations show that the particle size of the preferred catalyst was less than 50 nm.Based on results drawn from XRD, FT-IR, pyridine adsorbed FT-IR, UV-Vis DRS studies, model structures were proposed for Turkish perlite and all prepared catalysts.During this work, the catalytic potential of the preferred catalyst was compared with other previously reported catalysts and it showed appreciable results. The formed products were further confirmed by their melting point and 1 H-NMR analysis.

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“…Food grade silicon dioxide (SiO 2 ) has been known to have very low toxicity with a NOAEL (no observed adverse effect level) of over 2000 mg/kg when ingested orally [ 3 , 4 ]. However, various environmental factors such as heating, pH change, and potential interaction with food ingredients imposed during food processing may cause undesirable alterations in the physicochemical properties of food additive SiO 2 present in processed food, which may lead to changes in its toxicity [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. In fact, studies have shown that the particle size is an important parameter that determines the penetrating nature of SiO 2 in biological tissues, which may also increase its toxicity [ 10 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Synthetic Ligand-Coated Starch Magnetic Microbeads for Selective Extraction of Food Additive Silicon Dioxide from Commercial Processed Food

et al. 2021

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The amorphous form of silicon dioxide has long been regarded as a safe food additive (E551) that is widely used in commercially processed food as an anticaking agent. However, starting with titanium dioxide, there have been growing safety concerns regarding to the use of nanoscale silicon dioxide particles in food as food additives. The size, morphology, and chemical properties of inorganic food materials are important parameters to determine its potential toxicity. Therefore, an effective means of extracting an intact form of SiO2 from food without altering the physicochemical property of SiO2 particles is of great need to accurately monitor its characteristics. Here, we report on an effective magnetic separation method to extract food additive SiO2 from food by utilizing a diatom-originated peptide with a specific affinity to SiO2 particles. The affinity-based magnetic separation was found to be specific to SiO2 particles over other types of inorganic food additives such as titanium dioxide and zinc oxide. The size and morphology of SiO2 were shown to not be affected by the extraction processes. This method was successfully applied to extract and characterize the food additive SiO2 from six different types of commercial food.

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Study of the thermal treatment of SiO₂aggregate

Cited by 28 publications

References 25 publications

The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

Turkish perlite supported nickel oxide as the heterogeneous acid catalyst for a series of Claisen–Schmidt condensation reactions

Synthetic Ligand-Coated Starch Magnetic Microbeads for Selective Extraction of Food Additive Silicon Dioxide from Commercial Processed Food

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Study of the thermal treatment of SiO2aggregate

Cited by 28 publications

References 25 publications

The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

The Effect of Size and Thermal Treatment on the Photoluminescent Properties of Europium-Doped SiO2 Nanoparticles Prepared in One Pot by Sol-Gel

Turkish perlite supported nickel oxide as the heterogeneous acid catalyst for a series of Claisen–Schmidt condensation reactions

Synthetic Ligand-Coated Starch Magnetic Microbeads for Selective Extraction of Food Additive Silicon Dioxide from Commercial Processed Food

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Study of the thermal treatment of SiO₂aggregate