Ozonation of aqueous azo dye in a semi-batch reactor

Wu, Jiangning; Wang, Tingwei

doi:10.1016/s0043-1354(00)00330-4

Cited by 152 publications

(106 citation statements)

References 18 publications

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“…Approximately a reduction of 40-45 % COD was achieved after 10 minutes of ozonation followed by micron filtration. This was comparable with the reported values for COD reduction of 11-29 % (Perkowski, et al, 2000), 50 % (Selcuk, 2005), 27-87 % (Wu and Wang, 2001) and 5-20 % (Frank, 1994) respectively. A TOC reduction of 5 % at 5 min contact time and 43 % at 60 min contact time was reported (Balcioglu and Arslan, 2001).…”

Section: Discussionsupporting

confidence: 91%

Decolorisation of exhausted reactive dye bath using ozonator for reuse

Muthusubramanian

Vishnu

Joseph

2007

Int. J. Environ. Sci. Technol.

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Exhausted Reactive dye bath samples of Turquoise Blue, Olive Green and Navy Blue shades were collected from cotton knit wear dyeing units in Tirupur. Ozonation was conducted in a column reactor system fed with ozone at the rate of 0.16 g/min to assess its efficiency in reducing the color, chemical oxygen demand and total organic carbon. Complete decolorization of the effluent was achieved in 10 min contact time and ozone consumption of 153 mg/ L for Turquoise Blue, 128 for Olive Green and 143 for Navy Blue shades effluents respectively. The corresponding COD removal was 43 %, 44 % and 43 % for the three shades while TOC removal efficiency was 45 %, 45 % and 40% respectively. The results from the reusability studies indicate that the dyeing quality was not affected by the reuse of decolorized dye bath for two successive cycles. It is concluded that ozonation is efficient in decolorization of exhausted dye bath effluents containing conventional reactive dyes. However, the corresponding removal of COD from the textile effluent was not significant.

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Section: Discussionsupporting

confidence: 91%

Decolorisation of exhausted reactive dye bath using ozonator for reuse

Muthusubramanian

Vishnu

Joseph

2007

Int. J. Environ. Sci. Technol.

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“…Similar results were also reported that the slope of the linear curve represents the first-order rate constant and was about 1.09/min 31 . The same first-order types of behaviour were also reported elsewhere 35,36 .…”

Section: Decolourization Kineticssupporting

confidence: 82%

“…The pH of the dye-laden synthetic wastewater was adjusted to pH 7 prior to ozonation using a 0.1 N NaOH solution. The ozonation was evaluated at 5,10,15,20,25,30,35, and 40 min. For a given time, an increase in contact time has resulted in an increase in colour, COD, and TOC removal.…”

Section: Resultsmentioning

confidence: 99%

Decolourization of an azo dye in aqueous solution by ozonation in a semi-batch bubble column reactor

Abidin

Fahmi²,

Ong³

et al. 2015

ScienceAsia

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ABSTRACT:The oxidative degradation of the azo dye Reactive Red 120 by ozonation was investigated. The decolourization was carried out by bubbling ozone at the bottom of a bubble column reactor containing the dye solution. The colour, chemical oxygen demand, and total organic carbon removal were evaluated, and the contaminants were characterized based on the changes in UV-Vis and FT-IR spectra. It was observed that changes of UV-Vis spectra represent the disappearance of both azo and aromatic groups, which causes the colour removal. FT-IR analysis indicated that ozonation shifts the functional groups in the azo dye which results in decolourization, a decrease in aromaticity, and an increase in acidity. The results indicate that the chromophore is destroyed and partially mineralized to small fragments during ozonation. The alkaline pH was favourable to decomposition by ozonation, initiated by the formation of the hydroxyl radicals. The oxidation followed first-order kinetics and the completed decolourization confirmed the capability of ozonation to cleave the azo bond from the dye.

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“…Ozonation was performed in a cylindrical glass reactor (volume 1.2 l) by bubbling the ozone/air mixture at a volume stream of 20 l h À1 through a sintered glass filter (pore size 50-80 lm) fixed at the bottom of the reactor into the solution. The ozone concentration, representing the average concentration of commonly used, applied was 20.5 mg l À1 (Moraes de Gomes et al, 2000;Ciardelli and Ranieri, 2001;Wu and Wang, 2001).…”

Section: Ozonationmentioning

confidence: 99%

“…Typical concentrations of an exhausted RB 5 dye bath are considered to be between 0.8 and 2.6 g l À1 (Arslan and Balcioglu, 2000;Yediler et al, 2000). As the degradation rate of RB5 reacting with ozone depends on the dye concentration and on the ozone consumption, much longer ozonation periods (360 min) were chosen than commonly described (30-60 min) in the related literature (Moraes de Gomes et al, 2000;Ciardelli and Ranieri, 2001;Wu and Wang, 2001;Koch et al, 2002). Results obtained with the laboratory-scale experiments indicate however that a nearly complete decolourization can be achieved after 3 h of ozonation with an ozone concentration of 20.5 mg l À1 .…”

Section: Chemical Oxidationmentioning

confidence: 99%

Ozonation of an azo dye C.I. Remazol Black 5 and toxicological assessment of its oxidation products

et al. 2003

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The effect of ozonation (20.5 mg l À1 ) on the degradation processes of an azo dye, Remazol Black 5 (RB5; CI) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD 5=28 ), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that ozonation is a highly effective way to remove the colour of a corresponding dye solution. However, a considerable organic load still remained as indicated by high COD and TOC residues. The COD, TOC reductions were about 40% and 25% for 6 h ozonation of 2 g l À1 RB5 aqueous solution. During the ozonation process the rapid decrease of pH and the sharp increase of conductivity indicated the formation of acidic by-products and small fragments and ions which were identified by high performance ion chromatography. The BOD 28 data revealed that first by-products after partial ozonation (10-150 min) of RB5 were more biodegradable than the parent compound and ozonation can enhance the biodegradability of azo dyes. During the first 150 min of total 360 min of oxidation, the formation of first by-products with high toxic potential took place as it could be confirmed by two acute toxicity-screening tests, the bioluminescence test (Vibrio fischerii) and the neutral red cytotoxicity assay (rat hepatoma cells). The significant enhancement of microbial biodegradability after long-term ozonation could also be seen as a decrease of toxic intermediates in correlation with the ozonation time as indicated in BOD 28 biological degradation test results.

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Ozonation of aqueous azo dye in a semi-batch reactor

Cited by 152 publications

References 18 publications

Decolorisation of exhausted reactive dye bath using ozonator for reuse

Decolorisation of exhausted reactive dye bath using ozonator for reuse

Decolourization of an azo dye in aqueous solution by ozonation in a semi-batch bubble column reactor

Ozonation of an azo dye C.I. Remazol Black 5 and toxicological assessment of its oxidation products

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