Thermal behavior of silicophosphate gels obtained from different precursors

Todan, Ligia; Andronescu, Cristian; Vuluga, Dumitru Mircea; Culiță, Daniela C.; Zaharescu, Maria

doi:10.1007/s10973-012-2875-4

Cited by 21 publications

(18 citation statements)

References 30 publications

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“…Souza et al [12] obtained similar results, since that mass loss of silica pure was 22 %. Todan et al [26] also obtained the greatest mass loss in region I of the thermograph (around 100°C) for silica sol-gel prepared with different precursors. This result can be attributed to the presence of un-reacted silanol groups from the TEOS, which are present in the silica because of incomplete solgel reactions [29], as also could be attributed to water and alcohol elimination from the support [26].…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

“…Todan et al [26] also obtained the greatest mass loss in region I of the thermograph (around 100°C) for silica sol-gel prepared with different precursors. This result can be attributed to the presence of un-reacted silanol groups from the TEOS, which are present in the silica because of incomplete solgel reactions [29], as also could be attributed to water and alcohol elimination from the support [26]. Region I of the thermograph is mainly associated with extraction of water from the surface and the decomposition of amino groups, usually organic groups, up to a temperature of 200°C.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

“…1a, b) showed a type IV isotherm with a hysteresis loop, which is feature of mesoporous solids [25]. Todan et al [26] and Souza et al [11] obtained the same behaviour to silica solgel and encapsulated lipase from Bacillus sp. ITP-001 on silica sol-gel matrix, respectively.…”

Section: Specific Surface Area and Porositymentioning

confidence: 99%

See 2 more Smart Citations

Morphological and physicochemical aspects of microbial lipase obtained from novel agroindustrial waste encapsulated in a sol–gel matrix

Zubiolo

Santos

Figueiredo

et al. 2015

J Therm Anal Calorim

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The lipase from Aspergillus niger, obtained from solid-state fermentation of pumpkin seed flour, was encapsulated in a sol-gel matrix. The silica obtained by the sol-gel technique and lipase encapsulated were characterised with regard to superficial area, pore volume and size by nitrogen adsorption (BJH method), scanning electron microscopy, mass loss upon heating (TG) and differential scanning calorimetry. The immobilised biocatalyst and the sol-gel matrix showed features typical of mesoporous solids. The presence of the enzyme encapsulated in the solgel matrix was confirmed since the total mass loss of the BI at a temperature of 1,000°C was approximately 60 %, while for the free enzyme the mass loss was 95 %. This new lipase obtained from the fermentation of agroindustrial waste, which when encapsulated in sol-gel has physicalchemical and morphological features similar to those of conventional biocatalysts, maybe exploited for future applications in biocatalytic processes.

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Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

See 1 more Smart Citation

Morphological and physicochemical aspects of microbial lipase obtained from novel agroindustrial waste encapsulated in a sol–gel matrix

Zubiolo

Santos

Figueiredo

et al. 2015

J Therm Anal Calorim

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“…It is well known that H 3 PO 4 reacts strongly with (TEOS) leading to the formation of SiAOAP bonds [20], while TEP does not hydrolyze or condense in the presence of TEOS [21]. In this way, the gelation in the latter system is assigned only to the TEOS whereas TEP is embedded in the SiAOASi network [22][23][24]. The reaction mixture containing TEPI has an intermediate behavior due to its partial hydrolysis generating HOP(OC 2 H 5 ) 2 [21] that could allow formation of hydrogen bonds between the OH of phosphorous compound and the OH of the silica network.…”

Section: Introductionmentioning

confidence: 95%

“…Our earlier studies concerning the sol-gel preparation of phosphosilicate gels underlined that type of the phosphorous reagents (TEP, TEPI and H 3 PO 4 ) highly influences their composition and thermal behavior [20][21][22][23][24]. It is well known that H 3 PO 4 reacts strongly with (TEOS) leading to the formation of SiAOAP bonds [20], while TEP does not hydrolyze or condense in the presence of TEOS [21].…”

Section: Introductionmentioning

confidence: 99%

Structural characterization of some sol–gel derived phosphosilicate glasses

Todan

Anghel

Osiceanu

et al. 2015

Journal of Molecular Structure

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Synthesis, structural, and optical behavior of erbium‐doped silicophosphate glasses for photonics applications

Bouabdalli,

El Jouad,

Touhtouh

et al. 2024

Luminescence

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Erbium‐incorporated silicophosphate glasses are very desirable in principal sectors such as photonics, optoelectronics, lasers, and illuminating diodes. The focus of the current investigation has been on determining how the erbium dopant affects the optical, physical, and structural characteristics of the silicophosphate‐based glasses. The pure silicophosphate glasses and doped with various contents of erbium were prepared by the sol–gel process in this work. The noncrystalline character of the glasses synthesized was confirmed by the XRD patterns that were obtained. The optical measurement showed that the addition of trivalent erbium ions resulted in an increase in the refractive index of the samples and a decrease in their energy band gap values. It demonstrated the presence of P–O–P linkage stretching vibration modes that were both symmetrical and asymmetrical, P–O in PO4 bending vibration modes, OH group elongating and flexure vibrations, and P–O–H water absorption in glasses. The theoretical values of the optical basicity (Ʌth) increased from 0.465 to 0.472, while the values of the interaction parameter (A) decreased from 0.218 to 0.214 . Silicophosphate glasses doped with trivalent erbium ions show promise as optoelectronic and optical filter system materials.

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Thermal behavior of silicophosphate gels obtained from different precursors

Cited by 21 publications

References 30 publications

Morphological and physicochemical aspects of microbial lipase obtained from novel agroindustrial waste encapsulated in a sol–gel matrix

Morphological and physicochemical aspects of microbial lipase obtained from novel agroindustrial waste encapsulated in a sol–gel matrix

Structural characterization of some sol–gel derived phosphosilicate glasses

Synthesis, structural, and optical behavior of erbium‐doped silicophosphate glasses for photonics applications

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