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

S. A. El-Safty*

*この研究の対応する著者

研究成果: Article査読

30 被引用数 (Scopus)

抄録

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.

本文言語English
ページ(範囲)184-194
ページ数11
ジャーナルJournal of Colloid and Interface Science
260
1
DOI
出版ステータスPublished - 2003 4 1
外部発表はい

ASJC Scopus subject areas

  • コロイド化学および表面化学
  • 物理化学および理論化学
  • 表面および界面

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