The difference between the surface reactivity of amorphous silica in the gas and liquid phase due to material porosity

Prelot, Bénédicte; Lantenois, Sébastien; Nédellec, Yannig; Lindheimer, Marc; Douillard, Jean-Marc; Zając, Jerzy

doi:10.1016/j.colsurfa.2009.11.035

Cited by 15 publications

(16 citation statements)

References 49 publications

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“…The determination of OH surface density in oxides is not a trivial task, as shown by the rich debate on the subject, especially when porous materials are considered. 39,43,44,[62][63][64][65][66][67] In this work, this estimation was obtained on the MSN sample by employing TG analysis, as proposed in ref. 43 and 44. The OH surface density of the MSN sample was calculated by measuring its weight loss during a ramp in nitrogen from 150 1C to 1000 1C (Fig.…”

Section: General Properties Of the Samplesmentioning

confidence: 99%

Influence of surface functionalization on the hydrophilic character of mesoporous silica nanoparticles

Musso

Bottinelli

Celi

et al. 2015

Phys. Chem. Chem. Phys.

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We report the synthesis and surface functionalization of MCM-41-like mesoporous silica nanoparticles (MSNs) with spheroidal shape and particle size of 141 ± 41 nm. The success of surface functionalization with aminopropyl and sodium ethylcarboxylate groups (giving amino-MSN and carboxy-MSN, respectively) was ascertained by infrared spectroscopy and ζ potential measurements. The former showed the decrease of surface silanol groups and the corresponding appearance of signals related to NH2 bending mode (δNH2) at 1595 cm(-1) and COO(-) stretching (νas and νsym) at 1562 and 1418 cm(-1). The latter showed a change in surface charge, in that the isoelectric point (IEP) changed from pH 3-4.5 to 8.5 when the MSN was functionalized with the amino groups, while carboxy-MSN showed a more negative charge in the whole pH range with respect to MSN. The hydrophilic character of the prepared materials was ascertained by quantitative microgravimetric measurements, allowing the calculation of the average isosteric adsorption heat (q[combining macron]st). This was found to be 51 ± 3 kJ mol(-1), 61 ± 4, and 65 ± 3 kJ mol(-1) for MSN, amino-MSN, and carboxy-MSN samples, respectively. The increase in q[combining macron]st after functionalization can be ascribed to the specific interaction of water molecules with the functionalizing agents, in agreement with a higher basicity with respect to silanol groups. Moreover, the possibility of multiple H-bonding interactions of water molecules with the carboxylate anion is put forward to account for the higher water uptake with respect to parent MSN.

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Section: General Properties Of the Samplesmentioning

confidence: 99%

Influence of surface functionalization on the hydrophilic character of mesoporous silica nanoparticles

Musso

Bottinelli

Celi

et al. 2015

Phys. Chem. Chem. Phys.

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“…The simultaneous analysis of the adsorption of polar or polarizable probe molecules at the solid-gas and solid-liquid interfaces is exploitable only when both the phenomena lead to similar distribution functions (Villiéras et al 2002a;Garnier et al 2007). Nevertheless, it has been recently shown (Prélot et al 2010) that the image of surface reactivity of amorphous silica may drastically change when passing from the solid-gas to solid-water interface, particularly when the interfacial phenomena are accompanied by the confinement effects. The fact that argon adsorption serves to evaluate non-polar adsorption energy distributions is also utilized to establish the size and shape of such crystalline particles as clay minerals (Villiéras et al 1997b(Villiéras et al , 2002b or goethite (Prélot et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Evidences for the relationship between surface structure and reactivity of goethite nanoparticles based on advanced molecular-probe methods

et al. 2010

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Surface properties of two goethites have been studied in order to compare the amount of acid surface sites and their distribution over the various surface domains. For this purpose, ammonia, pyridine and nitrogen were used as basic molecular probes. Calorimetry measurements of ammonia adsorption provided the image of the average surface acidity being moderate. This conclusion was supported by the moderate resistance of the adsorbed pyridine molecules to degassing conditions. Adsorption and desorption of pyridine prior to gaseous nitrogen adsorption resulting in masking/unmasking of acid surface sites on the goethite surface allowed confirmation of the acid character of the specific adsorption sites characterized by the high-energy adsorption of electron-donating molecular nitrogen. The amount of acid sites probed by nitrogen and ammonia were of the same order of magnitude but systematically higher for ammonia. The subsequent analysis of the argon and nitrogen derivatives of first-layer adsorption isotherm led to determine the distribution of {101} and {121} crystallographic faces and discuss the location of acid sites on these surface domains.

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“…For example, the strontium sorption on XO75LS passes from 5.5 Â 10 À10 mol m À2 (1% uptake) at pH 7.1 to 1 Â 10 À8 mol m À2 (18.3% uptake) at pH 7.7, whereas the corresponding change in the surface density of negative charge is too small [36] to account for this effect. The hypothesis involving bulk interactions of appropriate cations with the dissolved silica, followed by the precipitation of the resulting silicate salts, cannot be validated in the present case.…”

Section: Discussionmentioning

confidence: 93%

“…This indicates that only a small fraction of the surface is involved in the overall sorption process. The weak retention of strontium on XO75LS, MCM-41, and MCF from acidic and neutral nitrate solutions may be ascribed to low density of surface charge on a porous or non-porous amorphous silica below pH 8.5 [36]. It should be also kept in mind that the adsorption of metal cations in the presence of a background electrolyte likely occurs via an ion-exchange mechanism [37].…”

Section: Discussionmentioning

confidence: 98%

Bulk hydrolysis and solid–liquid sorption of heavy metals in multi-component aqueous suspensions containing porous inorganic solids: Are these mechanisms competitive or cooperative?

Prelot

Einhorn

Marchandeau

et al. 2012

Journal of Colloid and Interface Science

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The difference between the surface reactivity of amorphous silica in the gas and liquid phase due to material porosity

Cited by 15 publications

References 49 publications

Influence of surface functionalization on the hydrophilic character of mesoporous silica nanoparticles

Influence of surface functionalization on the hydrophilic character of mesoporous silica nanoparticles

Evidences for the relationship between surface structure and reactivity of goethite nanoparticles based on advanced molecular-probe methods

Bulk hydrolysis and solid–liquid sorption of heavy metals in multi-component aqueous suspensions containing porous inorganic solids: Are these mechanisms competitive or cooperative?

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