Use of a sequencing batch biofilter for degradation of azo dyes (acids and bases)

2000 ◽  
Vol 42 (5-6) ◽  
pp. 329-336 ◽  
Author(s):  
M. Quezada ◽  
I. Linares ◽  
G. Buitrón

The degradation of azo dyes in an aerobic biofilter operated in an SBR system was studied. The azo dyes studied were Acid Red 151 and a textile effluent containing basic dyes (Basic Blue 41, Basic Red 46 and 16 and Basic Yellow 28 and 19). In the case of Acid Red 151 a maximal substrate degradation rate of 288 mg AR 151/lliquid·d was obtained and degradation efficiencies were between 60 and 99%. Mineralization studies showed that 73% (as carbon) of the initial azo dye was transformed to CO2 by the consortia. The textile effluent was efficiently biodegraded by the reactor. A maximal removal rate of 2.3 kg COD/lliquid·d was obtained with removal efficiencies (as COD) varying from 76 to 97%. In all the cycles the system presented 80% of colour removal.

2019 ◽  
Vol 8 (49) ◽  
Author(s):  
Ivette Fuentes ◽  
Robert Ccorahua ◽  
Oscar Tinoco ◽  
Oscar León ◽  
Pablo Ramírez

Here, we report the annotated genome sequences of two Shewanella sp. strains isolated from textile industry wastewater effluent in Peru. Potential genes for encoding enzymes that enable the strain to decolorize and degrade textile azo dyes were detected in both genomes.


1998 ◽  
Vol 38 (7) ◽  
pp. 19-24 ◽  
Author(s):  
C.-J. Lu ◽  
C. M. Lee ◽  
M.-S. Chung

The comparison of TCE cometabolic removal by methane, toluene, and phenol utilizers was conducted with a series of batch reactors. Methane, toluene, or phenol enriched microorganisms were used as cell source. The initial cell concentration was about 107 cfu/mL. Methane, toluene, and phenol could be readily biodegraded resulting in the cometabolic removal of TCE. Among the three primary carbon sources studied, the presence of phenol provided the best cometabolic removal of TCE. When the concentration of carbon source was 3 mg-C/L, the initial TCE removal rates initiated by methane, toluene, and phenol utilizers were 1.5, 30, and 100 μg/L-hr, respectively. During the incubation period of 80 hours, TCE removal efficiencies were 26% and 96% with the presence of methane and toluene, respectively. However, it was 100% within 20 hours with the presence of phenol. For phenol utilizers, the initial TCE removal rates were about the same, when the phenol concentrations were 1.35, 2.7, and 4.5 mg/L. However, TCE removal was not proportional to the concentrations of phenol. TCE removal was hindered when the phenol concentration was higher than 4.5 mg/L because of the rapid depletion of dissolved oxygen. The presence of toluene also initiated cometabolic removal of TCE. The presence of toluene at 3 and 5 mg/L resulted in similar TCE removal. The initial TCE removal rate was about 95 μg/L-hr at toluene concentrations of 3 and 5 mg/L compared to 20 μg/L-hr at toluene concentration of 1 mg/L.


2011 ◽  
Vol 181-182 ◽  
pp. 257-260
Author(s):  
David Statman ◽  
Andrew Jockers ◽  
Daniel Brennan

Chiral nematic liquid crystals prepared with Grandjean texture demonstrate a photonic bandgap whose central wavelength is proportional to the pitch length, P, of the liquid crystal and whose width is given by (ne – no)P. We show that methyl red doped chiral nematics undergo a shift in the photonic bandgap upon photo-isomerization. This shift is a result of (1) photo-induced change in anchoring energy on the nematic surface, and (2) change in the natural pitch length from the photo-isomerization of the azo dye.


1997 ◽  
Vol 36 (6-7) ◽  
pp. 65-72 ◽  
Author(s):  
Elías Razo-Flores ◽  
Maurice Luijten ◽  
Brian Donlon ◽  
Gatze Lettinga ◽  
Jim Field

Biological treatment of wastewaters discharged by the textile industry could potentially be problematic due to the high toxicity and recalcitrance of the commonly-used azo dye compounds. In the present report, the fate of two azo dyes under methanogenic conditions was studied. Mordant Orange 1 (MO1) and Azodisalicylate (ADS) were completely reduced and decolorised in continuous UASB reactors in the presence of cosubstrates. In the MO1 reactor, both 5-aminosalicylic acid (5-ASA) and 1,4-phenylenediamine were identified as products of azo cleavage. After long adaptation periods, 5-ASA was detected at trace levels, indicating further mineralization. ADS, a pharmaceutical azo dye constructed from two 5-ASA units, was completely mineralized even in the absence of cosubstrate, indicating that the metabolism of 5-ASA could provide the reducing equivalents needed for the azo reduction. Batch experiments confirmed the ADS mineralization. These results demonstrate that some azo dyes could serve as a carbon, energy, and nitrogen source for anaerobic bacteria.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Siddhesh Umesh Mestry ◽  
Umesh Ratan Mahajan ◽  
Aswathy M. ◽  
Shashank T. Mhaske

Purpose The purpose of this paper is to use the bio-based resource as the starting material for the synthesis of azo dye. Cardanol is one of the most used bio-based resources for carrying out the synthesis of various compounds having numerous end applications. The study presents an attempt to develop an azo dye from Cardanol having end applications in pH-responsive dyes. Design/methodology/approach The cardanol was sulfonated to block the para position by which ortho positioned hydroxyl group after diazotization and coupling will provide necessary pH-sensitivity. The diazotization of two naphthalene derivatives, i.e. 1-naphthol-8-amino-3,6-disulfonic acid (H-acid) and 7-amino-4-hydroxy-2-naphthalene sulfonic acid (J-acid) was carried out using the standard practice, and the diazotized compounds were coupled with the sulfonated cardanol. The obtained dyes were characterized by Fourier transform infrared, nuclear magnetic resonance, carbon-hydrogen-nitrogen-sulfur analysis and hydroxyl value. The colour properties were checked using UV-vis spectrophotometry and density functional theory, while thermogravimetric analysis was used for the thermal degradation studies of both the dyes. Findings Water-soluble cardanol-based azo dyes were prepared successfully having good thermal stability, and the obtained results are being presented in this paper. Originality/value The originality lies between the use of cardanol as a bio-based resource for the synthesis of azo-dye and the obtained azo-dye has the pH-sensitivity.


Author(s):  
Veena Gayathri Krishnaswamy

The limited availability of fresh water is a global crisis. The growing consumption of fresh water due to anthropogenic activities has taken its toll on available water resources. Unfortunately, water bodies are still used as sinks for waste water from domestic and industrial sources. Azo dyes account for the majority of all dye stuffs, produced because they are extensively used in the textile, paper, food, leather, cosmetics, and pharmaceutical industries. Bacterial degradation of azo dyes under certain environmental conditions has gained momentum as a method of treatment, as these are inexpensive, eco-friendly, and can be applied to wide range of such complex dyes. The enzymatic approach has attracted much interest with regard to degradation of azo dyes from wastewater. The oxido-reductive enzymes are responsible for generating highly reactive free radicals that undergo complex series of spontaneous cleavage reactions, due to the susceptibility of enzymes to inactivation in the presence of the other chemicals. The oxidoreductive enzymes, such as lignin peroxidase, laccases, tyrosinase, azoreductase, riboflavin reductive, polyphenol oxidase, and aminopyrine n-demethylase, have been mainly utilized in the bacterial degradation of azo dye. Along with the reductive enzymes, some investigators have demonstrated the involvement in some other enzymes, such as Lignin peroxides and other enzymes. This chapter reviews the importance of enzymes in dye degradation.


2011 ◽  
Vol 14 (11) ◽  
pp. 610-618 ◽  
Author(s):  
R. Rajendran ◽  
S. Karthik Sundaram ◽  
P. Prabhavath ◽  
B.V. Sridevi ◽  
V. Gopi

2010 ◽  
Vol 37 (11) ◽  
pp. 1492-1504
Author(s):  
Mamata Sharma ◽  
Nihar Biswas

Sulfate (1500 mg/L) reduction and glucose (1870 mg/L) degradation was examined in the presence of five varying linoleic acid (LA) levels (100–1000 mg/L) at 37 ± 2 °C and pH 7.0–7.2. The sulfate reduction and methane formation data suggest that LA selectively inhibited methane producing bacteria (MPB). The quantity of sulfate removed increased with increasing LA dosage. Approximately 1375 mg/L (92%) sulfate was removed in cultures fed with high concentrations of LA (1000 mg/L), which was 68% more than that removed in glucose and sulfate controls. The quantity of sulfate removed in cultures fed with 100, 300, 500 and 700 mg/L LA were 62%, 66%, 77%, and 84%, respectively. Initial sulfate degradation rates increased with increasing LA levels in the cultures. High LA levels (1000 mg/L) attributed to approximately a sevenfold increase in the initial sulfate degradation rates compared to cultures containing sulfate plus glucose. The highest initial sulfate removal rate (0.19 µg/(mgVSS min)) was observed in cultures receiving 1000 mg/L LA. Initial glucose degradation rates decreased with increasing LA concentrations. The rates for the cultures receiving 1000 mg/L LA were 2.53 µg/(mgVSS min) while the degradation rate for cultures containing 100 mg/L LA was 5.40 µg/(mgVSS min). Methane formation decreased when sulfate and LA were added. Methane formation was lowest in cultures receiving elevated LA concentrations. The percent electron flow fluxes increased towards sulfidogenesis and decreased towards methanogenesis with increasing LA levels. Less than 0.6% electron flow was diverted to methanogenesis in cultures containing high levels of LA (≥700 mg/L) while ≤ 45% was diverted to sulfidogenesis. Acetate and propionate were the major volatile fatty acids (VFAs) detected during glucose degradation. The amount of sulfate reduced in the cultures receiving only LA or sulfate and no other carbon source was comparable (approximately 10%), which suggests that LA did not contribute to electrons during the course of experiment for sulfate reduction.


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