Photooxidation of dichloroacetic acid controlled by pH-stat technique using TiO2/layer silicate nanocomposites

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Nanocomposites containing anatase nanoparticles were prepared by heterocoagulation, using Na-montmorillonite and titanium dioxide obtained by hydrothermal sol-gel method. Heterocoagulation was carried out at pH 1 and 4. Based on X-ray diffraction measurements, an average particle size of 3.8-4.0 nm was calculated by the Scherrer equation for the particles intercalated between the silicate lamellae. Nitrogen adsorption studies revealed that the specific surface area of nanocomposites prepared at pH 1 varies in the range of 157-284 m2/g, depending on the TiO2 content. After preparation at pH 4, the specific surface area of the samples is lower (123-248 m2/g). UV-vis analyses of the nanocomposites showed that as TiO2 content is increased, band gap energies relative to TiO2 decrease and gradually approach the value obtained for the pure sol-gel TiO2 sample (Eg = 3.12 eV). The nanocomposites obtained were tested in photocatalytic degradation of dichloroacetic acid (DCA) in a suspension photoreactor. The reaction was quantitatively monitored during the entire irradiation time using the pH-stat technique. We found that higher catalytic efficiencies could be achieved when increasing sample TiO2 content. The photocatalytic efficiency of composites prepared at pH 1 was well below that of the samples prepared at pH 4, which was attributed to structural changes in the support brought about by the highly acidic medium. When photocatalytic degradation data were normalized to pure TiO2, composite samples containing 47% and 57% TiO2 were found to be the most efficient as compared to the 100% TiO2 sample prepared by the sol-gel method.

Original languageEnglish
Pages (from-to)49-58
Number of pages10
JournalApplied Catalysis B: Environmental
Volume68
Issue number1-2
DOIs
Publication statusPublished - Oct 26 2006

Fingerprint

Dichloroacetic Acid
Dichloroacetic acid
Silicates
Photooxidation
photooxidation
Nanocomposites
gel
silicate
acid
surface area
Specific surface area
Titanium dioxide
Sol-gel process
degradation
anatase
Bentonite
montmorillonite
structural change
Degradation
Composite materials

Keywords

  • Dichloroacetic acid
  • Layer silicate
  • pH-stat
  • Photooxidation
  • TiO

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Environmental Chemistry

Cite this

@article{17553248e88f410b9efac5790d5daf9c,
title = "Photooxidation of dichloroacetic acid controlled by pH-stat technique using TiO2/layer silicate nanocomposites",
abstract = "Nanocomposites containing anatase nanoparticles were prepared by heterocoagulation, using Na-montmorillonite and titanium dioxide obtained by hydrothermal sol-gel method. Heterocoagulation was carried out at pH 1 and 4. Based on X-ray diffraction measurements, an average particle size of 3.8-4.0 nm was calculated by the Scherrer equation for the particles intercalated between the silicate lamellae. Nitrogen adsorption studies revealed that the specific surface area of nanocomposites prepared at pH 1 varies in the range of 157-284 m2/g, depending on the TiO2 content. After preparation at pH 4, the specific surface area of the samples is lower (123-248 m2/g). UV-vis analyses of the nanocomposites showed that as TiO2 content is increased, band gap energies relative to TiO2 decrease and gradually approach the value obtained for the pure sol-gel TiO2 sample (Eg = 3.12 eV). The nanocomposites obtained were tested in photocatalytic degradation of dichloroacetic acid (DCA) in a suspension photoreactor. The reaction was quantitatively monitored during the entire irradiation time using the pH-stat technique. We found that higher catalytic efficiencies could be achieved when increasing sample TiO2 content. The photocatalytic efficiency of composites prepared at pH 1 was well below that of the samples prepared at pH 4, which was attributed to structural changes in the support brought about by the highly acidic medium. When photocatalytic degradation data were normalized to pure TiO2, composite samples containing 47{\%} and 57{\%} TiO2 were found to be the most efficient as compared to the 100{\%} TiO2 sample prepared by the sol-gel method.",
keywords = "Dichloroacetic acid, Layer silicate, pH-stat, Photooxidation, TiO",
author = "Robert Kun and M. Szekeres and I. D{\'e}k{\'a}ny",
year = "2006",
month = "10",
day = "26",
doi = "10.1016/j.apcatb.2006.07.012",
language = "English",
volume = "68",
pages = "49--58",
journal = "Applied Catalysis B: Environmental",
issn = "0926-3373",
publisher = "Elsevier",
number = "1-2",

}

TY - JOUR

T1 - Photooxidation of dichloroacetic acid controlled by pH-stat technique using TiO2/layer silicate nanocomposites

AU - Kun, Robert

AU - Szekeres, M.

AU - Dékány, I.

PY - 2006/10/26

Y1 - 2006/10/26

N2 - Nanocomposites containing anatase nanoparticles were prepared by heterocoagulation, using Na-montmorillonite and titanium dioxide obtained by hydrothermal sol-gel method. Heterocoagulation was carried out at pH 1 and 4. Based on X-ray diffraction measurements, an average particle size of 3.8-4.0 nm was calculated by the Scherrer equation for the particles intercalated between the silicate lamellae. Nitrogen adsorption studies revealed that the specific surface area of nanocomposites prepared at pH 1 varies in the range of 157-284 m2/g, depending on the TiO2 content. After preparation at pH 4, the specific surface area of the samples is lower (123-248 m2/g). UV-vis analyses of the nanocomposites showed that as TiO2 content is increased, band gap energies relative to TiO2 decrease and gradually approach the value obtained for the pure sol-gel TiO2 sample (Eg = 3.12 eV). The nanocomposites obtained were tested in photocatalytic degradation of dichloroacetic acid (DCA) in a suspension photoreactor. The reaction was quantitatively monitored during the entire irradiation time using the pH-stat technique. We found that higher catalytic efficiencies could be achieved when increasing sample TiO2 content. The photocatalytic efficiency of composites prepared at pH 1 was well below that of the samples prepared at pH 4, which was attributed to structural changes in the support brought about by the highly acidic medium. When photocatalytic degradation data were normalized to pure TiO2, composite samples containing 47% and 57% TiO2 were found to be the most efficient as compared to the 100% TiO2 sample prepared by the sol-gel method.

AB - Nanocomposites containing anatase nanoparticles were prepared by heterocoagulation, using Na-montmorillonite and titanium dioxide obtained by hydrothermal sol-gel method. Heterocoagulation was carried out at pH 1 and 4. Based on X-ray diffraction measurements, an average particle size of 3.8-4.0 nm was calculated by the Scherrer equation for the particles intercalated between the silicate lamellae. Nitrogen adsorption studies revealed that the specific surface area of nanocomposites prepared at pH 1 varies in the range of 157-284 m2/g, depending on the TiO2 content. After preparation at pH 4, the specific surface area of the samples is lower (123-248 m2/g). UV-vis analyses of the nanocomposites showed that as TiO2 content is increased, band gap energies relative to TiO2 decrease and gradually approach the value obtained for the pure sol-gel TiO2 sample (Eg = 3.12 eV). The nanocomposites obtained were tested in photocatalytic degradation of dichloroacetic acid (DCA) in a suspension photoreactor. The reaction was quantitatively monitored during the entire irradiation time using the pH-stat technique. We found that higher catalytic efficiencies could be achieved when increasing sample TiO2 content. The photocatalytic efficiency of composites prepared at pH 1 was well below that of the samples prepared at pH 4, which was attributed to structural changes in the support brought about by the highly acidic medium. When photocatalytic degradation data were normalized to pure TiO2, composite samples containing 47% and 57% TiO2 were found to be the most efficient as compared to the 100% TiO2 sample prepared by the sol-gel method.

KW - Dichloroacetic acid

KW - Layer silicate

KW - pH-stat

KW - Photooxidation

KW - TiO

UR - http://www.scopus.com/inward/record.url?scp=33749233962&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749233962&partnerID=8YFLogxK

U2 - 10.1016/j.apcatb.2006.07.012

DO - 10.1016/j.apcatb.2006.07.012

M3 - Article

AN - SCOPUS:33749233962

VL - 68

SP - 49

EP - 58

JO - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

SN - 0926-3373

IS - 1-2

ER -