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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 13, No. 4, 2016, pp. 1077-1088
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Bioline Code: st16101
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 13, No. 4, 2016, pp. 1077-1088
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Photocatalytic activity evaluation of TiO2 nanoparticles based on COD analyses for water treatment applications: a standardization attempt
Mekkawi, D. M. EL-; Galal, H. R.; Abd EL Wahab, R. M. & Mohamed, W. A. A.
Abstract
Evaluation of the photocatalytic activities of
TiO2 nanomaterials based on the chemical oxygen demand
(COD) analyses under identical experimental conditions
was not previously reported. In this work, COD has been
selected as an adequate industrial water quality measure
toward the establishment of a representative standard test
method. The initial COD values of six organic pollutants
representing dye, surfactants, phenols and alcohol were set
at 30 ± 2 mg/L. Ten of different commercial and synthesized
TiO2 samples representing anatase, rutile and mixed
phases were used and characterized. The data of photocatalytic
processes were compared to that obtained using
the commonly widespread Degussa-P25 TiO2 (TD). The
COD of all pollutants was completely removed by TD at
UV exposure dose ≤9.36 mWh/cm2. Consequently, the
maximum irradiation dose was set at this value in all
experiments. The percentages of COD removal as well as
the values of the accumulated UV doses required for
complete removal of pollutants were measured using the
different TiO2 samples. TiO2 samples show different performance
abilities toward the various pollutants compared
to TD. Based on the obtained data, TiO2 photocatalysts
were divided into two categories according to the hydroxyl
radical formation rates. Comparison with previous studies
reveals that the photocatalytic efficiency evaluation
depends on the method of measurement. COD is
recommended to be used as an adequate technique of
analysis that meets the purpose of water treatment
applications.
Keywords
Photocatalytic activity; Nanosized TiO2; Organic pollutants; Water treatment; Chemical oxygen demand (COD); Standard test method
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