Effect of nonsurfactant template content on the particle size and surface area of monodisperse mesoporous silica nanospheres

Mukherjee, Indraneil; Mylonakis, Andreas; Guo, Yi; Samuel, Solomon Praveen; Li, Shuxi; Wei, Robert Y.; Kojtari, Adeline; Wei, Yen

doi:10.1016/j.micromeso.2009.02.030

Cited by 45 publications

(37 citation statements)

References 52 publications

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“…It can be seen in Figure 3 that the MIP sample showed a weight loss of only 22% at 473.1 K. Pre-sumably in this first stage part of this weight loss was due to the loss of surface water and also to the removal of water molecules that were not tightly bound to the silica matrix, in accordance with the literature (Wei et al, 1999;Mukherjee et al, 2009;Wanyika et al, 2011). At two other stages, the loss in weight at higher temperatures was ascribed to loss of surface silanol groups (Wanyika et al, 2011).…”

Section: Thermogravimetric Analysis (Tga)supporting

confidence: 87%

Adsorption Process of Molecularly Imprinted Silica for Extraction of Lactose From Milk

Balieiro

Santos

Pereira

et al. 2016

Braz. J. Chem. Eng.

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-In Brazil, about 25-30% of the population has some degree of intolerance to lactose, a disorder associated with the inability of the body to digest lactose due to a disability or absence of the enzyme lactase. The goal of this study was to evaluate the performance of adsorption of lactose from fresh milk using a fixed bed column of molecularly imprinted polymer (MIP). The polymeric material was characterized using Scanning electron microscopy (SEM) analysis, thermal analysis (e.g., differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), and the method of Braunauer, Emmet and Teller (BET). The adsorption column dynamics and performance were studied by the breakthrough curves using a 2 4-1 fractional factorial design. The chemical and structural characterization of the pure matrix and imprinted polymers confirmed the molecularly imprinted polymer (MIP) imprinted with lactose. The highest capacity was 62.21 mgg -1 , obtained at 307.1 K and a flow rate of 12.5 mL.min -1 , with central point conditions, 320.1 K and 9 mL.min -1 , with an average value of 50.9 mg.g -1 . The results indicate that the molecularly imprinted polymer is efficient.

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Section: Thermogravimetric Analysis (Tga)supporting

confidence: 87%

Adsorption Process of Molecularly Imprinted Silica for Extraction of Lactose From Milk

Balieiro

Santos

Pereira

et al. 2016

Braz. J. Chem. Eng.

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“…Region II, which has temperatures between 200 and 600 °C, is associated with the condensation of silanol groups and some loss of organic components (C, H, O and N) in the volatile form either present or formed until the onset of decomposition biological, including lipase and the presence of silanol groups of the unreacted TEOS, because of the incomplete sol-gel reaction, according to Mukherjee and colleagues. 38 Region III, where the mass loss is associated with final dehydroxylation reactions and definitive carbonisation of organic compounds, resulting in complete degradation of the material or thermal stability, was investigated by Soares and colleagues. 4 Thermogravimetric analysis showed that all the gel samples exhibit more weight loss up to 100 °C, which corresponds to the evaporation of alcohol and residual water formed during the hydrolysis of -Si-OCH 2 CH 3 functionalities and condensation of silanol (-Si-OH) groups.…”

Section: Thermogravimetric Analysis -Tgmentioning

confidence: 99%

“…In the thermogravimetric analysis the low weight loss was also observed by Souza and colleagues 12 and can be attributed to the presence of un-reacted silanol groups from the TEOS, which are present in the silica because of incomplete sol-gel reactions. 38 For SAIL and biocatalysts ADSIL and CBIL some of this weight loss is also owed to the removal of water molecules, which were tightly bound to the silica matrix because of the presence of the ionic liquid protic resulting from interactions between silane precursors and organic components (additives and lipase). 12 …”

Section: Thermogravimetric Analysis -Tgmentioning

confidence: 99%

The Novel Mesoporous Silica Aerogel Modified With Protic Ionic Liquid for Lipase Immobilization

Barbosa¹,

Lisboa²,

Silva³

et al. 2016

Química Nova

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Recebido em 24/08/2015; aceito em 22/12/2015; publicado na web em 11/02/2016Mesoporous silica supports (aerogels) were used to immobilize Burkholderia cepacia lipase (BC) by encapsulation (EN or ENIL), physical adsorption (ADS or ADSIL) and covalent binding (CB or CBIL) into or onto the aerogel modified with protic ionic liquid (PIL). Yield immobilization (Ya) and operational stability were determined by the hydrolytic reaction of olive oil. Ya (37% to 83% by physical adsorption) and operational stability (2 to 23 batches by encapsulation) increased when the support was modified with PIL. For immobilized derivates observed by the BET method, in this case ADS and CB for ADSIL and CBIL, increased pores size was observed, possibly due to the higher amount of BC immobilized conferring Ya and operational stability. This effect was probably attributed to the entry of the enzyme into the pores of the silica aerogel structure. SEM images showed a change in the structure and properties of immobilized lipase derived with PIL. A characteristic FTIR band was obtained for the silanol groups and amides I, IV and V, demonstrating the efficiency of immobilization of BC. The most efficient biocatalysts were ADSIL with regard to yield immobilization and ENIL for operational stability.

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“…The use of CTAB/SPEEK as structuredirecting agents results in hierarchical mesoporous silica that contains hexagonally ordered mesopores (2nm) directed by CTAB and larger mesopores (20-50 nm) directed by SPEEK [10]. A convenient and environmentally friendly synthesis of monodispersed and mesoporous silica nanospheres by the addition of sugar molecules like glucose and fructose as templates into the Stober process is reported by Mukherjee [11], wherein silica nanoparticles of 50-1140 nm were produced by simply increasing template concentration in a reaction mixture consisting of TEOS, NH3, H2O, ethanol and the nonsurfactant sugar templates. Spherical mesoporous silica particles with tunable pore size and tunable outer particle diameter in the nanometer range were successfully prepared in a water/oil phase using organic templates method by Okuyama [12].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Silica Nanoparticles and its Beneficial Role in Cementitious Materials

Singh

Agarwal

Bhattacharyya

et al. 2011

Nanomaterials and Nanotechnology

117

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Spherical silica nanoparticles (n-SiO2) with controllable size have been synthesized using tetraethoxysilane as starting material and ethanol as solvent by sol-gel method. Morphology and size of the particles was controlled through surfactants. Sorbitan monolaurate, sorbitain monopalmitate and sorbitain monostearate produced silica nanoparticles of varying sizes (80-150 nm), indicating the effect of chain length of the surfactant. Increase in chain length of non-ionic surfactant resulted in decreasing particle size of silica nanoparticles. Further, the size of silica particles was also controlled using NH3 as base catalyst. These silica nanoparticles were incorporated into cement paste and their role in accelerating the cementitious reactions was investigated. Addition of silica nanoparticles into cement paste improved the microstructure of the paste and calcium leaching is significantly reduced as n-SiO2 reacts with calcium hydroxide and form additional calciumsilicate-hydrate (C-S-H) gel. It was found that calcium hydroxide content in silica nanoparticles incorporated cement paste reduced ~89% at 1 day and up to ~60% at 28 days of hydration process. Synthesized silica particles and cement paste samples were characterized using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), infrared spectroscopy (IR) and thermogravimetric analysis (TGA).

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Effect of nonsurfactant template content on the particle size and surface area of monodisperse mesoporous silica nanospheres

Cited by 45 publications

References 52 publications

Adsorption Process of Molecularly Imprinted Silica for Extraction of Lactose From Milk

Adsorption Process of Molecularly Imprinted Silica for Extraction of Lactose From Milk

The Novel Mesoporous Silica Aerogel Modified With Protic Ionic Liquid for Lipase Immobilization

Preparation of Silica Nanoparticles and its Beneficial Role in Cementitious Materials

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