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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. 7, No. 2, 2010, pp. 377-384
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Bioline Code: st10037
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. 7, No. 2, 2010, pp. 377-384
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Degradation of trace aqueous 4-chloro-2-nitrophenol occurring in pharmaceutical industrial wastewater by ozone
Gharbani, P.; Khosravi, M.; Tabatabaii, S. M.; Zare, K.; Dastmalchi, S. & Mehrizad, A.
Abstract
Degradation of 4-chloro-2-nitro phenol by ozonation in aqueous solution was studied in a semi batch
reactor under constant ozone dosage and variable pH conditions. The effectiveness of the process was estimated based
on the degree of conversion of 4-chloro-2-nitro phenol. It was observed that ozonation is more effective at alkaline
reaction of medium than other conditions. The degree of conversion achieved (at the first 5 minutes of the process)at pH
9 was 99.64% compared to 99.03% and 77.35% at pH 7 and 3, respectively. Another parameter used to quantify the 4-
chloro-2-nitrophenol during ozonation was the pseudo first order rate constant k [min-1]. Results showed that the rate
constant of the process was approximately much higher at the alkaline pH compared to acidic ones. A considerable
improvement in chemical oxygen demand removal was observed at pH above 7. At pH 9, the reduction in chemical
oxygen demand at the end of the process reached 56.9 %. The degree of organically bounded nitrogen conversion to
nitrate was higher at pH 3. Of the total organic carbon reduction, 15.89 % was observed at pH 9. The 4-chloro-2-nitro
phenol degradation intermediate products were analyzed by mass- spectrometry. The main intermediate product was
chlorophenol.
Keywords
Chemical oxygen demand; Degradation; Kinetic; Mineralization; Total organic carbon
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