Sorption and diffusion of phenols onto well-defined ordered nanoporous monolithic silicas

S. A. El-Safty

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The sorption of phenol, and o-, m-, and p-aminophenol (o-, m-, and p-AP) onto highly ordered mesoporous silicas (HOM) with cubic Im3m (HOM-1), hexagonal HI (HOM-2), 3-D hexagonal p63/mmc (HOM-3), cubic Ia3d (HOM-5), lamellar L (HOM-6), and solid phase S (HOM-8) materials has been investigated kinetically. Nanostructured silica molecular sieves have been prepared at 25 and 60°C with lyotropic liquid-crystalline phases of the nonionic surfactant (Brij 76) that was used as a structure-directing agent. Such nanostructured silicas have been studied by 29Si nuclear magnetic resonance (29Si NMR), powder X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method for nitrogen adsorption and surface area measurements, and transmission electron microscopy (TEM) techniques after synthesis and sorption. It was found that all materials exhibit well-defined long-range porous architectures without significant loss of the ordered texture during phenol sorption. The kinetics of phenol sorption has been studied spectrophotometrically at different temperatures (25-40°C; ±0.1 range). The sorption rate is zero order in all phenols sorbed, and increases directly in the pattern P>m-AP>o-AP>p-AP, which reflects the mobility of the phenol compounds on the particle pores. The isothermal sorption and the kinetic parameters were discussed and it was established that a diffusion-controlled process characterizes phenol sorption. Furthermore, the mechanism of phenol sorption was deduced to be predominantly particle diffusion. The diffusion coefficients were determined using Fick's equation. The trend of diffusion of all phenols onto nanoporous silica was HOM-8>HOM-2>HOM-6>HOM-5>HOM-1>HOM-3, reflecting the effect of the uniform pore size distribution and the internal surface area of the nanostructured silicas on the diffusion process.

Original languageEnglish
Pages (from-to)184-194
Number of pages11
JournalJournal of Colloid and Interface Science
Volume260
Issue number1
DOIs
Publication statusPublished - 2003 Apr 1
Externally publishedYes

Fingerprint

Phenols
Silicon Dioxide
phenols
sorption
Sorption
Silica
silicon dioxide
Phenol
porosity
particle diffusion
Nonionic surfactants
Molecular sieves
kinetics
absorbents
Kinetic parameters

Keywords

  • Diffusion
  • Kinetics
  • Nanostructured molecular sieves
  • Phenol compounds
  • Sorption
  • Surfactant

ASJC Scopus subject areas

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

Cite this

Sorption and diffusion of phenols onto well-defined ordered nanoporous monolithic silicas. / El-Safty, S. A.

In: Journal of Colloid and Interface Science, Vol. 260, No. 1, 01.04.2003, p. 184-194.

Research output: Contribution to journalArticle

@article{6b5c52677b7f43128ed8e95a23b6fbcf,
title = "Sorption and diffusion of phenols onto well-defined ordered nanoporous monolithic silicas",
abstract = "The sorption of phenol, and o-, m-, and p-aminophenol (o-, m-, and p-AP) onto highly ordered mesoporous silicas (HOM) with cubic Im3m (HOM-1), hexagonal HI (HOM-2), 3-D hexagonal p63/mmc (HOM-3), cubic Ia3d (HOM-5), lamellar L∞ (HOM-6), and solid phase S (HOM-8) materials has been investigated kinetically. Nanostructured silica molecular sieves have been prepared at 25 and 60°C with lyotropic liquid-crystalline phases of the nonionic surfactant (Brij 76) that was used as a structure-directing agent. Such nanostructured silicas have been studied by 29Si nuclear magnetic resonance (29Si NMR), powder X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method for nitrogen adsorption and surface area measurements, and transmission electron microscopy (TEM) techniques after synthesis and sorption. It was found that all materials exhibit well-defined long-range porous architectures without significant loss of the ordered texture during phenol sorption. The kinetics of phenol sorption has been studied spectrophotometrically at different temperatures (25-40°C; ±0.1 range). The sorption rate is zero order in all phenols sorbed, and increases directly in the pattern P>m-AP>o-AP>p-AP, which reflects the mobility of the phenol compounds on the particle pores. The isothermal sorption and the kinetic parameters were discussed and it was established that a diffusion-controlled process characterizes phenol sorption. Furthermore, the mechanism of phenol sorption was deduced to be predominantly particle diffusion. The diffusion coefficients were determined using Fick's equation. The trend of diffusion of all phenols onto nanoporous silica was HOM-8>HOM-2>HOM-6>HOM-5>HOM-1>HOM-3, reflecting the effect of the uniform pore size distribution and the internal surface area of the nanostructured silicas on the diffusion process.",
keywords = "Diffusion, Kinetics, Nanostructured molecular sieves, Phenol compounds, Sorption, Surfactant",
author = "El-Safty, {S. A.}",
year = "2003",
month = "4",
day = "1",
doi = "10.1016/S0021-9797(02)00212-6",
language = "English",
volume = "260",
pages = "184--194",
journal = "Journal of Colloid and Interface Science",
issn = "0021-9797",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Sorption and diffusion of phenols onto well-defined ordered nanoporous monolithic silicas

AU - El-Safty, S. A.

PY - 2003/4/1

Y1 - 2003/4/1

N2 - The sorption of phenol, and o-, m-, and p-aminophenol (o-, m-, and p-AP) onto highly ordered mesoporous silicas (HOM) with cubic Im3m (HOM-1), hexagonal HI (HOM-2), 3-D hexagonal p63/mmc (HOM-3), cubic Ia3d (HOM-5), lamellar L∞ (HOM-6), and solid phase S (HOM-8) materials has been investigated kinetically. Nanostructured silica molecular sieves have been prepared at 25 and 60°C with lyotropic liquid-crystalline phases of the nonionic surfactant (Brij 76) that was used as a structure-directing agent. Such nanostructured silicas have been studied by 29Si nuclear magnetic resonance (29Si NMR), powder X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method for nitrogen adsorption and surface area measurements, and transmission electron microscopy (TEM) techniques after synthesis and sorption. It was found that all materials exhibit well-defined long-range porous architectures without significant loss of the ordered texture during phenol sorption. The kinetics of phenol sorption has been studied spectrophotometrically at different temperatures (25-40°C; ±0.1 range). The sorption rate is zero order in all phenols sorbed, and increases directly in the pattern P>m-AP>o-AP>p-AP, which reflects the mobility of the phenol compounds on the particle pores. The isothermal sorption and the kinetic parameters were discussed and it was established that a diffusion-controlled process characterizes phenol sorption. Furthermore, the mechanism of phenol sorption was deduced to be predominantly particle diffusion. The diffusion coefficients were determined using Fick's equation. The trend of diffusion of all phenols onto nanoporous silica was HOM-8>HOM-2>HOM-6>HOM-5>HOM-1>HOM-3, reflecting the effect of the uniform pore size distribution and the internal surface area of the nanostructured silicas on the diffusion process.

AB - The sorption of phenol, and o-, m-, and p-aminophenol (o-, m-, and p-AP) onto highly ordered mesoporous silicas (HOM) with cubic Im3m (HOM-1), hexagonal HI (HOM-2), 3-D hexagonal p63/mmc (HOM-3), cubic Ia3d (HOM-5), lamellar L∞ (HOM-6), and solid phase S (HOM-8) materials has been investigated kinetically. Nanostructured silica molecular sieves have been prepared at 25 and 60°C with lyotropic liquid-crystalline phases of the nonionic surfactant (Brij 76) that was used as a structure-directing agent. Such nanostructured silicas have been studied by 29Si nuclear magnetic resonance (29Si NMR), powder X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) method for nitrogen adsorption and surface area measurements, and transmission electron microscopy (TEM) techniques after synthesis and sorption. It was found that all materials exhibit well-defined long-range porous architectures without significant loss of the ordered texture during phenol sorption. The kinetics of phenol sorption has been studied spectrophotometrically at different temperatures (25-40°C; ±0.1 range). The sorption rate is zero order in all phenols sorbed, and increases directly in the pattern P>m-AP>o-AP>p-AP, which reflects the mobility of the phenol compounds on the particle pores. The isothermal sorption and the kinetic parameters were discussed and it was established that a diffusion-controlled process characterizes phenol sorption. Furthermore, the mechanism of phenol sorption was deduced to be predominantly particle diffusion. The diffusion coefficients were determined using Fick's equation. The trend of diffusion of all phenols onto nanoporous silica was HOM-8>HOM-2>HOM-6>HOM-5>HOM-1>HOM-3, reflecting the effect of the uniform pore size distribution and the internal surface area of the nanostructured silicas on the diffusion process.

KW - Diffusion

KW - Kinetics

KW - Nanostructured molecular sieves

KW - Phenol compounds

KW - Sorption

KW - Surfactant

UR - http://www.scopus.com/inward/record.url?scp=0037374803&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037374803&partnerID=8YFLogxK

U2 - 10.1016/S0021-9797(02)00212-6

DO - 10.1016/S0021-9797(02)00212-6

M3 - Article

VL - 260

SP - 184

EP - 194

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 1

ER -