Surface acidity and hydrophilicity of coprecipitated Al2O3-SiO2 xerogels prepared from aluminium nitrate nonahydrate and tetraethylorthosilicate

Kiyoshi Okada, Takahiro Tomita, Yoshikazu Kameshima, Atsuo Yasumori, Kenneth J D MacKenzie

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Amorphous aluminosilicate xerogels with various chemical compositions were prepared by coprecipitation, and their surface acidity and hydrophilicity were investigated by NH3 gas temperature programmed desorption (TPD), water vapor adsorption-desorption isotherms, and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR). The xerogels were synthesized by adding conc. NH4OH to an ethanol solution of calculated amounts of aluminium nitrate nonahydrate and tetraethylorthosilicate, and calcined at 300°C for 4 h. All the NH3 TPD spectra of the xerogels showed similar asymmetric peak profiles at around 200°C tailing to the higher temperature side. The amount of acidity evaluated from the peak area of the TPD spectra showed a maximum at around 10 mol% Al2O3 composition. The change as a function of composition showed a good correlation with the total amount of four and five coordinated Al atoms in the xerogels deduced from the 27Al MAS NMR spectra. The water vapor adsorption isotherms of the xerogels were all of type IV irrespective of the composition. The maximum amounts of water vapor adsorbed by these xerogels were about 600-700 ml(STP)/g and were relatively high compared with those for various other adsorbents reported so far. Since the thickness of the adsorbed water vapor layer of the xerogels in the low relative pressure region increased with increasing Al2O3 content, the surface of the xerogels is considered to become more hydrophilic with increasing Al2O3 content of the xerogels.

Original languageEnglish
Pages (from-to)195-200
Number of pages6
JournalJournal of Colloid and Interface Science
Volume219
Issue number1
DOIs
Publication statusPublished - Nov 1 1999
Externally publishedYes

Fingerprint

Xerogels
xerogels
Hydrophilicity
Acidity
acidity
nitrates
Nitrates
aluminum
Aluminum
Steam
Water vapor
water vapor
Temperature programmed desorption
desorption
Magic angle spinning
Chemical analysis
metal spinning
isotherms
Nuclear magnetic resonance
tetraethoxysilane

Keywords

  • Aluminosilicate xerogel
  • Coprecipitation
  • Hydrophilicity
  • Surface acidity
  • Water vapor adsorption

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Surface acidity and hydrophilicity of coprecipitated Al2O3-SiO2 xerogels prepared from aluminium nitrate nonahydrate and tetraethylorthosilicate. / Okada, Kiyoshi; Tomita, Takahiro; Kameshima, Yoshikazu; Yasumori, Atsuo; MacKenzie, Kenneth J D.

In: Journal of Colloid and Interface Science, Vol. 219, No. 1, 01.11.1999, p. 195-200.

Research output: Contribution to journalArticle

@article{2fc8211733484f629c86b1305ae05072,
title = "Surface acidity and hydrophilicity of coprecipitated Al2O3-SiO2 xerogels prepared from aluminium nitrate nonahydrate and tetraethylorthosilicate",
abstract = "Amorphous aluminosilicate xerogels with various chemical compositions were prepared by coprecipitation, and their surface acidity and hydrophilicity were investigated by NH3 gas temperature programmed desorption (TPD), water vapor adsorption-desorption isotherms, and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR). The xerogels were synthesized by adding conc. NH4OH to an ethanol solution of calculated amounts of aluminium nitrate nonahydrate and tetraethylorthosilicate, and calcined at 300°C for 4 h. All the NH3 TPD spectra of the xerogels showed similar asymmetric peak profiles at around 200°C tailing to the higher temperature side. The amount of acidity evaluated from the peak area of the TPD spectra showed a maximum at around 10 mol{\%} Al2O3 composition. The change as a function of composition showed a good correlation with the total amount of four and five coordinated Al atoms in the xerogels deduced from the 27Al MAS NMR spectra. The water vapor adsorption isotherms of the xerogels were all of type IV irrespective of the composition. The maximum amounts of water vapor adsorbed by these xerogels were about 600-700 ml(STP)/g and were relatively high compared with those for various other adsorbents reported so far. Since the thickness of the adsorbed water vapor layer of the xerogels in the low relative pressure region increased with increasing Al2O3 content, the surface of the xerogels is considered to become more hydrophilic with increasing Al2O3 content of the xerogels.",
keywords = "Aluminosilicate xerogel, Coprecipitation, Hydrophilicity, Surface acidity, Water vapor adsorption",
author = "Kiyoshi Okada and Takahiro Tomita and Yoshikazu Kameshima and Atsuo Yasumori and MacKenzie, {Kenneth J D}",
year = "1999",
month = "11",
day = "1",
doi = "10.1006/jcis.1999.6461",
language = "English",
volume = "219",
pages = "195--200",
journal = "Journal of Colloid and Interface Science",
issn = "0021-9797",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Surface acidity and hydrophilicity of coprecipitated Al2O3-SiO2 xerogels prepared from aluminium nitrate nonahydrate and tetraethylorthosilicate

AU - Okada, Kiyoshi

AU - Tomita, Takahiro

AU - Kameshima, Yoshikazu

AU - Yasumori, Atsuo

AU - MacKenzie, Kenneth J D

PY - 1999/11/1

Y1 - 1999/11/1

N2 - Amorphous aluminosilicate xerogels with various chemical compositions were prepared by coprecipitation, and their surface acidity and hydrophilicity were investigated by NH3 gas temperature programmed desorption (TPD), water vapor adsorption-desorption isotherms, and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR). The xerogels were synthesized by adding conc. NH4OH to an ethanol solution of calculated amounts of aluminium nitrate nonahydrate and tetraethylorthosilicate, and calcined at 300°C for 4 h. All the NH3 TPD spectra of the xerogels showed similar asymmetric peak profiles at around 200°C tailing to the higher temperature side. The amount of acidity evaluated from the peak area of the TPD spectra showed a maximum at around 10 mol% Al2O3 composition. The change as a function of composition showed a good correlation with the total amount of four and five coordinated Al atoms in the xerogels deduced from the 27Al MAS NMR spectra. The water vapor adsorption isotherms of the xerogels were all of type IV irrespective of the composition. The maximum amounts of water vapor adsorbed by these xerogels were about 600-700 ml(STP)/g and were relatively high compared with those for various other adsorbents reported so far. Since the thickness of the adsorbed water vapor layer of the xerogels in the low relative pressure region increased with increasing Al2O3 content, the surface of the xerogels is considered to become more hydrophilic with increasing Al2O3 content of the xerogels.

AB - Amorphous aluminosilicate xerogels with various chemical compositions were prepared by coprecipitation, and their surface acidity and hydrophilicity were investigated by NH3 gas temperature programmed desorption (TPD), water vapor adsorption-desorption isotherms, and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR). The xerogels were synthesized by adding conc. NH4OH to an ethanol solution of calculated amounts of aluminium nitrate nonahydrate and tetraethylorthosilicate, and calcined at 300°C for 4 h. All the NH3 TPD spectra of the xerogels showed similar asymmetric peak profiles at around 200°C tailing to the higher temperature side. The amount of acidity evaluated from the peak area of the TPD spectra showed a maximum at around 10 mol% Al2O3 composition. The change as a function of composition showed a good correlation with the total amount of four and five coordinated Al atoms in the xerogels deduced from the 27Al MAS NMR spectra. The water vapor adsorption isotherms of the xerogels were all of type IV irrespective of the composition. The maximum amounts of water vapor adsorbed by these xerogels were about 600-700 ml(STP)/g and were relatively high compared with those for various other adsorbents reported so far. Since the thickness of the adsorbed water vapor layer of the xerogels in the low relative pressure region increased with increasing Al2O3 content, the surface of the xerogels is considered to become more hydrophilic with increasing Al2O3 content of the xerogels.

KW - Aluminosilicate xerogel

KW - Coprecipitation

KW - Hydrophilicity

KW - Surface acidity

KW - Water vapor adsorption

UR - http://www.scopus.com/inward/record.url?scp=0033230226&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033230226&partnerID=8YFLogxK

U2 - 10.1006/jcis.1999.6461

DO - 10.1006/jcis.1999.6461

M3 - Article

VL - 219

SP - 195

EP - 200

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 1

ER -