• Advances in environmental research
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• 제3권4호
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• pp.293-306
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• 2014

The present study primarily focuses on the evaluation of the comparative effect of chemical coagulation and ultrasonication for elimination of aromatic amines (AAs) present in anaerobically pretreated textile wastewater containing different types of dyes including azo dyes. Color and COD reduction was also monitored at the optimized conditions. The production of AAs was measured spectrophotometrically in the form of total aromatic amines (TAAs) and also verified with high performance liquid chromatography (HPLC) selectively. A composite coagulant, magnesium chloride (MC) aided with aluminium chlorohydrate (ACH) in an equal ratio (MC + ACH) was utilized during the coagulation process, which yielded 31% of TAAs removal along with 85% of color and 52% of COD reduction. At optimized power (200 W) and sonication time (5 h), an appreciable TAAs degradation efficiency (85%) was observed along with 51% color reduction and 62% COD removal using ultrasonication. The chromatographic data indicate that sulphanilic acid and benzidine types of aromatic amines were produced after the reductive cleavage of utilized textile dyes, which were effectively mineralized after ultrasonication. The degradation followed the first order kinetics with a correlation coefficient ($R^2$) of 0.89 and a first-order kinetic constant (k) of $0.0073min^{-1}$.

• 한국물환경학회지
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• 제22권2호
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• pp.333-341
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• 2006

The concept for the decolorization in biological dye wastewater treatment systems is based on anaerobic treatment, for the reductive cleavage of the dyes' azo linkages, in combination with aerobic treatment, for the degradation of the products from azo dye cleavage, aromatic amines. Batch tests were conducted to examine the conditions and the factors affecting biological treatment of dye wastewater. From the tests, the removal efficiencies of organics and colors of dyeing wastewater were improved to $COD_{Cr}$ 27% and color 9% by injecting 10% of the domestic wastewater as a cosubstrate, and $COD_{Cr}$ 30%, color 22% with 30% injection of domestic wastewater. Therefore it was proved that decolorization efficiency is demonstrated with domestic wastewater as a cosubstrate. The analysis of aromatic amines in wastewater showed that decolorization was achieved by cometabolism while aromatic amines were produced by cleavage of azo bonds under anaerobic conditions and these products were removed in an aerobic tank subsequently.

• 한국수산과학회지
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• 제40권5호
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• pp.282-287
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• 2007

Chloroanilines are aromatic amines used as intermediate products in the synthesis of herbicides, azo-dyes, and pharmaceuticals. 3,4-dichloroaniline (DCA) is the degradation product of some herbicides (diuron, propanil, and linuron) and of trichlorocarbanilide, a chemical used as an active agent in the cosmetic industry. The compound, however, is considered a potential pollutant due to its toxicity and recalcitrant property to humans and other species. With the increasing necessity for bioremediation, we sought to isolate bacteria that degraded 3,4-DCA. A bacterium capable of growth on 3,4-DCA as the sole carbon source was isolated from seaside sediment using a dilution method with a culture enriched in 3,4-DCA. The isolated strain, YM-7 was identified to be Pseudomonas sp. The isolated strain was also able to degrade other chloroaniline compounds. The isolated strain showed a high level of catechol 2,3-dioxygenase activity on exposure to 3,4-DCA, suggesting that this enzyme is an important factor in 3,4-DCA degradation. The activity toward 4-methylcatechol was 53.1% that of catechol, while the activity toward 3-methylcatechol, 4-chlorocatechol and 4,5-chlorocatechol was 18.1, 33.1, and 6.9%, respectively.