Science.gov

Sample records for azo dye acid

  1. Multiwavelength spectrophotometric determination of acidity constants of some azo dyes

    NASA Astrophysics Data System (ADS)

    Shamsipur, Mojtaba; Maddah, Bozorgmehr; Hemmateenejad, Bahram; Rouhani, Shohreh; Haghbeen, Kamaladin; Alizadeh, Kamal

    2008-06-01

    A multiwavelength spectrophotometric titration method was applied to study the acidity constants of some azo dyes in water. The UV-vis absorption spectra of azo dye solutions were recorded in the course of their pH-metric titration with a standard base solution. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components have been calculated. The quantitative effects of the substituents on the acidity of the studied azo dyes were investigated by the linear free energy relationship (LFER) using Hammet sigma constant ( σ) and field and resonance effects of Kamlet and Taft ( f and ℜ, respectively).

  2. Multiwavelength spectrophotometric determination of acidity constants of some azo dyes.

    PubMed

    Shamsipur, Mojtaba; Maddah, Bozorgmehr; Hemmateenejad, Bahram; Rouhani, Shohreh; Haghbeen, Kamaladin; Alizadeh, Kamal

    2008-06-01

    A multiwavelength spectrophotometric titration method was applied to study the acidity constants of some azo dyes in water. The UV-vis absorption spectra of azo dye solutions were recorded in the course of their pH-metric titration with a standard base solution. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components have been calculated. The quantitative effects of the substituents on the acidity of the studied azo dyes were investigated by the linear free energy relationship (LFER) using Hammet sigma constant (sigma) and field and resonance effects of Kamlet and Taft (f and Re, respectively).

  3. 40 CFR 721.980 - Sodium salt of azo acid dye.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sodium salt of azo acid dye. 721.980... Substances § 721.980 Sodium salt of azo acid dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a sodium salt of azo acid dye (PMN...

  4. 40 CFR 721.980 - Sodium salt of azo acid dye.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sodium salt of azo acid dye. 721.980... Substances § 721.980 Sodium salt of azo acid dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a sodium salt of azo acid dye (PMN...

  5. 40 CFR 721.10633 - Aromatic sulfonic acid amino azo dye salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic sulfonic acid amino azo dye... Specific Chemical Substances § 721.10633 Aromatic sulfonic acid amino azo dye salts (generic). (a) Chemical... as aromatic sulfonic acid amino azo dye salts (PMN P-12-276) is subject to reporting under...

  6. 40 CFR 721.10633 - Aromatic sulfonic acid amino azo dye salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic sulfonic acid amino azo dye... Specific Chemical Substances § 721.10633 Aromatic sulfonic acid amino azo dye salts (generic). (a) Chemical... as aromatic sulfonic acid amino azo dye salts (PMN P-12-276) is subject to reporting under...

  7. 40 CFR 721.980 - Sodium salt of azo acid dye.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Sodium salt of azo acid dye. 721.980... Substances § 721.980 Sodium salt of azo acid dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a sodium salt of azo acid dye (PMN...

  8. 40 CFR 721.980 - Sodium salt of azo acid dye.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Sodium salt of azo acid dye. 721.980... Substances § 721.980 Sodium salt of azo acid dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a sodium salt of azo acid dye (PMN...

  9. 40 CFR 721.980 - Sodium salt of azo acid dye.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Sodium salt of azo acid dye. 721.980... Substances § 721.980 Sodium salt of azo acid dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a sodium salt of azo acid dye (PMN...

  10. Modification of azo dyes by lactic acid bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identification of microorganisms capable of utilizing azo dyes have been an area of significant interest due to their role in the treatment of waste water derived from the textile industry. The ability of L. casei LA1133 and L. paracasei LA0471 to modify the azo dye tartrazine was recently document...

  11. Ozonation of azo dyes (Orange II and Acid Red 27) in saline media.

    PubMed

    Silva, Alessandra C; Pic, Jean Stephane; Sant'Anna, Geraldo L; Dezotti, Marcia

    2009-09-30

    Ozonation of two azo dyes was investigated in a monitored bench scale bubble column reactor (8.5-L), varying liquid media salt content (0, 1, 40 and 100 g L(-1), NaCl). In experiments with Orange II pH was varied (5, 7.5 and 9) but ozonation of Acid Red 27 was performed at pH 7.5. Ozone self-decomposition rate-constant increased with salt concentration. Color removal was very effective and fast achieved under all experimental conditions. For the two azo dyes tested, more than 98% of color intensity was removed in 30-min ozonation assays. However, only partial mineralization of azo dyes (45%-Orange II; 20%-Acid Red 27) was attained in such experiments. The degree of mineralization (TOC removal) was negatively affected by salt concentration. Biodegradation assays conducted by respirometry revealed the inhibitory effect of dye degradation products formed during ozonation.

  12. Azo dye Acid Red 27 decomposition kinetics during ozone oxidation and adsorption processes.

    PubMed

    Beak, Mi H; Ijagbemi, Christianah O; Kim, Dong S

    2009-05-01

    To elucidate the effects of ozone dosage, catalysts, and temperature on azo dye decomposition rate in treatment processes, the decomposition kinetics of Acid Red 27 by ozone was investigated. Acid Red 27 decomposition rate followed the first-order reaction with complete dye discoloration in 20 min of ozone reaction. The dye decay rate increases as ozone dosage increases. Using Mn, Zn and Ni as transition metal catalysts during the ozone oxidation process, Mn displayed the greatest catalytic effect with significant increase in the rate of decomposition. The rate of decomposition decreases with increase in temperature and beyond 40 degrees C, increase in decomposition rate was followed by a corresponding increase in temperature. The FT-IR spectra in the range of 1,000-1,800 cm(-1) revealed specific band variations after the ozone oxidation process, portraying structural changes traceable to cleavage of bonds in the benzene ring, the sulphite salt group, and the C-N located beside the -N = N- bond. From the (1)H-NMR spectra, the breaking down of the benzene ring showed the disappearance of the 10 H peaks at 7-8 ppm, which later emerged with a new peak at 6.16 ppm. In a parallel batch test of azo dye Acid Red 27 adsorption onto activated carbon, a low adsorption capacity was observed in the adsorption test carried out after three minutes of ozone injection while the adsorption process without ozone injection yielded a high adsorption capacity.

  13. Reduction of an azo dye acid black 24 solution using synthesized nanoscale zerovalent iron particles.

    PubMed

    Shu, Hung-Yee; Chang, Ming-Chin; Yu, Hsing-Hung; Chen, Wang-Hung

    2007-10-01

    The strong color and high total organic carbon (TOC) of laboratory-synthesized azo dye, C.I. Acid Black 24 (AB24), solution was substantially reduced with particles of chemically synthesized nanoscale zerovalent iron (NZVI) under varied conditions of experimental variables such as NZVI dosage, initial dye concentration, and pH. From the results, the synthesized NZVI particles can effectively remove color and TOC of AB24 dye solution under certain conditions. The best removal efficiencies for color and TOC were obtained as 98.9 and 53.8%, respectively, with an initial dye concentration of 100 mg L(-1) and an NZVI dosage of 0.3348 g L(-1). Additionally, the removal rates followed an empirical rate equation with respect to the initial dye concentration as well as the NZVI dosage. The NZVI dosage addition exponentially increments the removal efficiency, with observed empirical reaction rate constants (k) of 0.046-0.603 min(-1) for added NZVI of 0.0335-0.3348 g L(-1). Moreover, the largest unit removal capacity was 609.4 mg of AB24 uptake for each gram of NZVI (i.e., 609.4 mg AB24/g NZVI). Ultimately, the ideal operation conditions were 0.1674-0.3348 g L(-1) of NZVI dosage, 15-30 min of reaction time, and pH 4-9 for 25-100 mg L(-1) of initial dye concentration.

  14. Decolorization of anthraquinone dye intermediate and its accelerating effect on reduction of azo acid dyes by Sphingomonas xenophaga in anaerobic-aerobic process.

    PubMed

    Lu, Hong; Zhou, Jiti; Wang, Jing; Ai, Haixin; Zheng, Chunli; Yang, Yusuo

    2008-09-01

    Decolorization of 1-aminoanthraquinone-2-sulfonic acid (ASA-2) and its accelerating effect on the reduction of azo acid dyes by Sphingomonas xenophaga QYY were investigated. The study showed that ASA-2 could be efficiently decolorized by strain QYY under aerobic conditions according to the analysis of total organic carbon removal and UV-VIS spectra changes. Moreover, strain QYY was able to reduce azo acid dyes under anaerobic conditions. The effects of various operating conditions such as carbon sources, temperature, and pH on the reduction rate were studied. It was demonstrated that ASA-2 used as a redox mediator could accelerate the reduction process. Consequently the reduction of azo acid dyes mediated by ASA-2 and the decolorization of ASA-2 with strain QYY could be achieved in an anaerobic-aerobic process.

  15. Holographic gratings recorded in poly(lactic acid)/azo-dye films

    NASA Astrophysics Data System (ADS)

    Cambiasso, Javier; Goyanes, Silvia; Ledesma, Silvia

    2015-09-01

    Diffraction gratings were recorded in biodegradable polymer films of poly(lactic acid) doped with the photoisomerisable azo-dye (Disperse Orange 3). It is shown that the diffraction efficiency of the recorded grating can be improved by 220% via an all-optical treatment. This all-optical treatment consists of a pre-irradiation of the sample with the writing laser beam at high power during a short period of time, preventing damage of the material, followed by a much longer inscription at relatively low power. Furthermore, it is shown that the addition of a small amount of 0.05 wt% of multi-walled carbon nanotubes to the photoresponsive polymer increases the maximum diffraction efficiency as well as the remanent efficiency by 20%. Finally, this last photoresponsive nano-composite is also sensitive to the pre-irradiation treatment.

  16. Corrosion Inhibition of Carbon Steel by New Thiophene Azo Dye Derivatives in Acidic Solution

    NASA Astrophysics Data System (ADS)

    El-Haddad, Mahmoud N.; Fouda, A. S.; Mostafa, H. A.

    2013-08-01

    Inhibition of carbon steel corrosion in 2 M hydrochloric acid (HCl) solution by thiophene azo dye derivatives were studied using weight loss, electrochemical frequency modulation (EFM), and atomic absorption techniques. The experimental data suggest that the inhibition efficiency increases with increasing inhibitors concentration in presence of 103 μM potassium iodide (KI). This is due to synergistic effect. Thus, the experimental results suggested that the presence of these anions in the solution stabilized the adsorption of inhibitors molecules on the metal surface and improved the inhibition efficiency. The results of EFM experiments are a spectrum of current response as a function of frequency. The corrosion rate and Tafel parameters can be obtained with measurement by analyzing the harmonic frequencies. The adsorption of the inhibitors on metal surface obeys the Langmuir adsorption isotherm. The surface of metal examined using Fourier transform infrared and ultraviolet spectroscopy. Quantum chemical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  17. Enzyme-mediated bacterial biodegradation of an azo dye (C.I. Acid blue 113): reuse of treated dye wastewater in post-tanning operations.

    PubMed

    Senthilvelan, T; Kanagaraj, J; Panda, R C

    2014-11-01

    "Dyeing" is a common practice used to color the hides during the post-tanning operations in leather processing generating plenty of wastewater. The waste stream containing dye as pollutant is severely harmful to living beings. An azo dye (C.I. Acid Blue 113) has been biodegraded effectively by bacterial culture mediated with azoreductase enzyme to reduce the pollution load in the present investigation. The maximum rate of dye degradation was found to be 96 ± 4 and 92 ± 4 % for the initial concentrations of 100 and 200 mg/l, respectively. The enzyme activity was measured using NADH as a substrate. Fourier transform infrared spectroscopy (FT-IR) analysis was confirmed that the transformation of azo linkage could be transformed into N2 or NH3 or incorporated into complete biomass. Breaking down of dye molecules to various metabolites (such as aniline, naphthalene-1,4-diamine, 3-aminobenzenesulfonic acid, naphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5,8-diaminonaphthalene-1-sulfonic acid) was confirmed by gas chromatography and mass spectra (GC-MS) and mass (electrospray ionization (ESI)) spectra analysis. The treated wastewater could be reused for dyeing operation in the leather processing, and the properties of produced leather were evaluated by conventional methods that revealed to have improved dye penetration into the grain layer of experimental leather sample and resulted in high levelness of dyeing, which helps to obtain the desired smoothness and soft leather properties.

  18. Using resin supported nano zero-valent iron particles for decoloration of Acid Blue 113 azo dye solution.

    PubMed

    Shu, Hung-Yee; Chang, Ming-Chin; Chen, Chi-Chun; Chen, Po-En

    2010-12-15

    In this study, a synthesized cation exchange resin supported nano zero-valent iron (NZVI) complex forming NZVI-resin was proposed for the decoloration of an azo dye Acid Blue 113 (AB 113), taking into account reaction time, initial dye concentration, NZVI dose and pH. From results, the successful decoloration of the AB 113 solution was observed using a NZVI-resin. Increasing the iron load to 50.8 mg g(-1), the removal efficiencies of the AB 113 concentration increased exponentially. With an initial dye concentration of 100 mg l(-1) and nano iron load of 50.8 mg g(-1), the best removal efficiencies were obtained at 100 and 12.6% for dye concentration and total organic carbon, respectively. Color removal efficiency was dependent on initial dye concentration and iron load. Moreover, the removal rates followed modified pseudo-first order kinetic equations with respect to dye concentration. Thus, the observed removal rate constants (k) were 0.137-0.756 min(-1) by NZVI loads of 4.9-50.8 mg g(-1). Consequently, the NZVI-resin performed effectively for the decoloration of AB 113 azo dye, offering great potential in the application of NZVI-resins in larger scale column tests and further field processes.

  19. Carcinogenicity of azo dyes: Acid Black 52 and Yellow 3 in hamsters and rats. Volume 2. Technical report (Final)

    SciTech Connect

    Plankenhorn, L.J.

    1983-09-30

    This document is an appendix to a study concerning the carcinogenicity of the azo dyes acid-black-52 and yellow-3 in male and female hamsters and rats and contains individual histopathology studies of both dyes. Histopathological features were reported in tabular form for the skin, mammary gland, muscle, salivary gland, mandibular lymph node, sciatic nerve, thymus, larynx, thyroid, parathyroid, trachea, bronchus, esophagus, adrenal, stomach, duodenum, jejunem, ileum, cecum, colon, rectum, mesenteric lymph node, lung, liver, gallbladder, spleen, pancreas, kidney, heart, urinary bladder, seminal vesicle, prostate, testis, cerebrum, cerebellum, pituitary, sternabrae, femur, bone marrow, and nasal cavity.

  20. Activated carbon catalyzed persulfate oxidation of Azo dye acid orange 7 at ambient temperature.

    PubMed

    Yang, Shiying; Yang, Xin; Shao, Xueting; Niu, Rui; Wang, Leilei

    2011-02-15

    Persulfate (PS) oxidative degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e.g., 25°C). It was observed that there existed a remarkable synergistic effect in the GAC/PS combined system. Higher PS concentration and GAC dosage resulted in higher AO7 degrading rates. Near-neutral was the optimal initial pH. Adsorption had an adverse effect on AO7 degradation. AO7 had not only a good decolorization, but a good mineralization. The decomposition of PS followed a first-order kinetics behavior both in the presence and in the absence of AO7. Radical mechanism was studied and three radical scavengers (methanol (MA), tert-butanol (TBA), phenol) were used to determine the kind of major active species taking part in the degradation of AO7 and the location of degradation reaction. It was assumed that the degradation of AO7 did not occur in the liquid phase, but in the porous bulk and boundary layer on the external surface of GAC. SO(4)(-•) or HO•, generated on or near the surface of GAC, played a major role in the AO7 degradation. Finally, the recovery performance of GAC was studied through the GAC reuse experiments.

  1. Bacterial Decolorization of Textile Azo Dye Acid Orange by Staphylococcus hominis RMLRT03

    PubMed Central

    Singh, Rajat Pratap; Singh, Pradeep Kumar; Singh, Ram Lakhan

    2014-01-01

    A bacterial strain RMLRT03 with ability to decolorize textile dye Acid Orange dye was isolated from textile effluent contaminated soil of Tanda, Ambedkar Nagar, Uttar Pradesh (India). The decolorization studies were performed in Bushnell and Haas medium (BHM) amended with Acid Orange dye. The bacterial strain was identified as Staphylococcus hominis on the basis of 16S rDNA sequence. The bacterial strain exhibited good decolorization ability with glucose and yeast extract supplementation as cosubstrate in static conditions. The optimal condition for the decolorization of Acid Orange dye by Staphylococcus hominis RMLRT03 strain were at pH 7.0 and 35°C in 60 h of incubation. The bacterial strain could tolerate high concentrations of Acid Orange dye up to 600 mg l-1. The high decolorizing activity under natural environmental conditions indicates that the bacterial strain has practical application in the treatment of dye containing wastewaters. PMID:25253925

  2. Bacterial Decolorization of Textile Azo Dye Acid Orange by Staphylococcus hominis RMLRT03.

    PubMed

    Singh, Rajat Pratap; Singh, Pradeep Kumar; Singh, Ram Lakhan

    2014-05-01

    A bacterial strain RMLRT03 with ability to decolorize textile dye Acid Orange dye was isolated from textile effluent contaminated soil of Tanda, Ambedkar Nagar, Uttar Pradesh (India). The decolorization studies were performed in Bushnell and Haas medium (BHM) amended with Acid Orange dye. The bacterial strain was identified as Staphylococcus hominis on the basis of 16S rDNA sequence. The bacterial strain exhibited good decolorization ability with glucose and yeast extract supplementation as cosubstrate in static conditions. The optimal condition for the decolorization of Acid Orange dye by Staphylococcus hominis RMLRT03 strain were at pH 7.0 and 35°C in 60 h of incubation. The bacterial strain could tolerate high concentrations of Acid Orange dye up to 600 mg l(-1). The high decolorizing activity under natural environmental conditions indicates that the bacterial strain has practical application in the treatment of dye containing wastewaters.

  3. Adsorption kinetics and equilibrium studies for removal of acid azo dyes by aniline formaldehyde condensate

    NASA Astrophysics Data System (ADS)

    Terangpi, Praisy; Chakraborty, Saswati

    2016-12-01

    Adsorption of two acid dyes named Acid orange 8 (AO8) and Acid violet 7 (AV7) by amine based polymer aniline formaldehyde condensate (AFC) was studied. Adsorption of both dyes was favored at acidic pH. Electrostatic attraction between protonated amine group (NH3 +) of AFC and anionic sulfonate group (SO3 -) of dye molecule along with hydrogen bond formation and interaction between aromatic group of dye and AFC were responsible mechanisms for dye uptake. Isotherm of AO8 was Type I and followed Langmuir isotherm model. AV7 isotherm on AFC was of Type III and followed Freundlich model. Kinetics study showed that external mass transfer was the rate limiting step followed by intraparticle diffusion. Maximum adsorption capacities of AO8 and AV7 were observed as 164 and 68 mg/g. AO8 dye being smaller in molecular size was adsorbed more due to higher diffusion rate and higher dye: AFC ratio, which enhanced the interaction between dye and polymer.

  4. Spectrophotometric determination of sildenafil citrate in pure form and in pharmaceutical formulation using some chromotropic acid azo dyes.

    PubMed

    Issa, Y M; El-Hawary, W F; Youssef, A F A; Senosy, A R

    2010-04-01

    Two simple and highly sensitive spectrophotometric methods were developed for the quantitative determination of the drug sildenafil citrate (SC), Viagra, in pure form and in pharmaceutical formulations, through ion-associate formation reactions (method A) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II) and ion-pair reactions (method B) with bi-chromotropic acid azo dyes, 3-phenylazo-6-o-carboxyphenylazo-chromotropic acid (III), bis-3,6-(o-hydroxyphenylazo)-chromotropic acid (IV), bis-3,6-(p-N,N-dimethylphenylazo)-chromotropic acid (V) and 3-phenylazo-6-o-hydroxyphenylazo-chromotorpic acid (VI). The reaction products, extractable in methylene chloride, were quantitatively measured at 540, 520, 540, 570, 600 and 575 nm using reagents, I-VI, respectively. The reaction conditions were studied and optimized. Beer's plots were linear in the concentration ranges 3.3-87.0, 3.3-96.0, 5.0-115.0, 2.5-125.0, 8.3-166.7 and 0.8-15.0 microg mL(-1) with corresponding molar absorptivities 1.02 x 10(4), 8.34 x 10(3), 6.86 x 10(3), 5.42 x 10(3), 3.35 x 10(3) and 2.32 x 10(4)Lmol(-1) cm(-1) using reagents I-VI, respectively. The limits of detection and Sandell's sensitivities were calculated. The methods were successfully applied to the analysis of commercial tablets (Vigoran) and the recovery study reveals that there is no interference from the common excipients that are present in tablets. Statistical comparison of the results was performed with regard to accuracy and precision using Student's t- and F-tests at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

  5. Spectrophotometric determination of sildenafil citrate in pure form and in pharmaceutical formulation using some chromotropic acid azo dyes

    NASA Astrophysics Data System (ADS)

    Issa, Y. M.; El-Hawary, W. F.; Youssef, A. F. A.; Senosy, A. R.

    2010-04-01

    Two simple and highly sensitive spectrophotometric methods were developed for the quantitative determination of the drug sildenafil citrate (SC), Viagra, in pure form and in pharmaceutical formulations, through ion-associate formation reactions (method A) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II) and ion-pair reactions (method B) with bi-chromotropic acid azo dyes, 3-phenylazo-6-o-carboxyphenylazo-chromotropic acid (III), bis-3,6-(o-hydroxyphenylazo)-chromotropic acid (IV), bis-3,6-(p-N,N-dimethylphenylazo)-chromotropic acid (V) and 3-phenylazo-6-o-hydroxyphenylazo-chromotorpic acid (VI). The reaction products, extractable in methylene chloride, were quantitatively measured at 540, 520, 540, 570, 600 and 575 nm using reagents, I-VI, respectively. The reaction conditions were studied and optimized. Beer's plots were linear in the concentration ranges 3.3-87.0, 3.3-96.0, 5.0-115.0, 2.5-125.0, 8.3-166.7 and 0.8-15.0 μg mL -1 with corresponding molar absorptivities 1.02 × 10 4, 8.34 × 10 3, 6.86 × 10 3, 5.42 × 10 3, 3.35 × 10 3 and 2.32 × 10 4 L mol -1 cm -1 using reagents I-VI, respectively. The limits of detection and Sandell's sensitivities were calculated. The methods were successfully applied to the analysis of commercial tablets (Vigoran) and the recovery study reveals that there is no interference from the common excipients that are present in tablets. Statistical comparison of the results was performed with regard to accuracy and precision using Student's t- and F-tests at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

  6. Highly Efficient Catalysis of Azo Dyes Using Recyclable Silver Nanoparticles Immobilized on Tannic Acid-Grafted Eggshell Membrane.

    PubMed

    Liu, Xiaojing; Liang, Miao; Liu, Mingyue; Su, Rongxin; Wang, Mengfan; Qi, Wei; He, Zhimin

    2016-12-01

    In this study, a facile one-step synthesis of a novel nanocomposite catalytic film was developed based on silver nanoparticles (AgNPs) immobilized in tannic acid-modified eggshell membrane (Tan-ESM). Tannic acid, as a typical plant polyphenol from oak wood, was first grafted onto ESM fibers to serve as both the reductant and the stabilizer during the synthesis of AgNPs. The morphology, constitution, and thermal stability of the resulting AgNPs@Tan-ESM composites were fully characterized to explain the excellent catalytic efficiency of AgNPs@Tan-ESM composites. These composite catalysts were applied to the degradation of azo dyes which exhibited the high catalytic activity toward Congo red and methyl orange according to the kinetic curves. More importantly, they can be easily recovered and reused for many times because of their good stability.

  7. Highly Efficient Catalysis of Azo Dyes Using Recyclable Silver Nanoparticles Immobilized on Tannic Acid-Grafted Eggshell Membrane

    NASA Astrophysics Data System (ADS)

    Liu, Xiaojing; Liang, Miao; Liu, Mingyue; Su, Rongxin; Wang, Mengfan; Qi, Wei; He, Zhimin

    2016-10-01

    In this study, a facile one-step synthesis of a novel nanocomposite catalytic film was developed based on silver nanoparticles (AgNPs) immobilized in tannic acid-modified eggshell membrane (Tan-ESM). Tannic acid, as a typical plant polyphenol from oak wood, was first grafted onto ESM fibers to serve as both the reductant and the stabilizer during the synthesis of AgNPs. The morphology, constitution, and thermal stability of the resulting AgNPs@Tan-ESM composites were fully characterized to explain the excellent catalytic efficiency of AgNPs@Tan-ESM composites. These composite catalysts were applied to the degradation of azo dyes which exhibited the high catalytic activity toward Congo red and methyl orange according to the kinetic curves. More importantly, they can be easily recovered and reused for many times because of their good stability.

  8. Remediation of textile azo dye acid red 114 by hairy roots of Ipomoea carnea Jacq. and assessment of degraded dye toxicity with human keratinocyte cell line.

    PubMed

    Jha, Pamela; Jobby, Renitta; Desai, N S

    2016-07-05

    Bioremediation has proven to be the most desirable and cost effective method to counter textile dye pollution. Hairy roots (HRs) of Ipomoea carnea J. were tested for decolourization of 25 textile azo dyes, out of which >90% decolourization was observed in 15 dyes. A diazo dye, Acid Red 114 was decolourized to >98% and hence, was chosen as the model dye. A significant increase in the activities of oxidoreductive enzymes was observed during decolourization of AR114. The phytodegradation of AR114 was confirmed by HPLC, UV-vis and FTIR spectroscopy. The possible metabolites were identified by GCMS as 4- aminobenzene sulfonic acid 2-methylaniline and 4- aminophenyl 4-ethyl benzene sulfonate and a probable pathway for the biodegradation of AR114 has been proposed. The nontoxic nature of the metabolites and toxicity of AR114 was confirmed by cytotoxicity tests on human keratinocyte cell line (HaCaT). When HaCaT cells were treated separately with 150 μg mL(-1) of AR114 and metabolites, MTT assay showed 50% and ≈100% viability respectively. Furthermore, flow cytometry data showed that, as compared to control, the cells in G2-M and death phase increased by 2.4 and 3.6 folds respectively on treatment with AR114 but remained unaltered in cells treated with metabolites.

  9. Decolorization of azo dyes by Geobacter metallireducens.

    PubMed

    Liu, Guangfei; Zhou, Jiti; Chen, Congcong; Wang, Jing; Jin, Ruofei; Lv, Hong

    2013-09-01

    Geobacter metallireducens was found to be capable of decolorizing several azo dyes with different structures to various extents. Pyruvate, ethanol, acetate, propionate, and benzoate could support 66.3 ± 2.6-93.7 ± 2.1 % decolorization of 0.1 mM acid red 27 (AR27) in 40 h. The dependence of the specific decolorization rate on AR27 concentration (25 to 800 μM) followed Michaelis-Menten kinetics (K m = 186.9 ± 1.4 μΜ, V max = 0.65 ± 0.02 μmol mg protein(-1) h(-1)). Enhanced AR27 decolorization was observed with the increase of cell concentrations ranging from 7.5 to 45 mgL(-1). AR27 decolorization by G. metallireducens was retarded by the presence of goethite, which competed electrons with AR27 and was reduced to Fe(II). The addition of low concentrations of humic acid (1-100 mgL(-1)) or 2-hydroxy-1,4-naphthoquinone (0.5-50 μM) could improve the decolorization performance of G. metallireducens. High-performance liquid chromatography analysis suggested reductive pathway to be responsible for decolorization. This was the first study on azo dye decolorization by Geobacter strain and might improve our understanding of natural attenuation and bioremediation of environments polluted by azo dyes.

  10. Organic acids enhanced decoloration of azo dye in gas phase surface discharge plasma system.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-01-25

    A gas phase surface discharge plasma combined with organic acids system was developed to enhance active species mass transfer and dye-containing wastewater treatment efficacy, with Acid Orange II (AO7) as the model pollutant. The effects of discharge voltage and various organic acid additives (acetic acid, lactic acid and nonoic acid) on AO7 decoloration efficiency were evaluated. The experimental results showed that an AO7 decoloration efficiency of approximately 69.0% was obtained within 4 min of discharge plasma treatment without organic acid addition, which was improved to 82.8%, 83.5% and 88.6% within the same treatment time with the addition of acetic acid, lactic acid and nonoic acid, respectively. The enhancement effects on AO7 decoloration efficiency could be attributed to the decrease in aqueous surface tension, improvement in bubble distribution and shape, and increase in ozone equivalent concentration. The AO7 wastewater was biodegradable after discharge plasma treatment with the addition of organic acid. AO7 decomposition intermediates were analyzed by UV-vis spectrometry and GC-MS; 2-naphthol, 1,4-benzoquinone, phthalic anhydride, coumarin, 1,2-naphthoquinone, and 2-formyl-benzoic acid were detected. A possible pathway for AO7 decomposition in this system was proposed.

  11. Enhanced anaerobic fermentation with azo dye as electron acceptor: simultaneous acceleration of organics decomposition and azo decolorization.

    PubMed

    Li, Yang; Zhang, Yaobin; Quan, Xie; Zhang, Jingxin; Chen, Shuo; Afzal, Shahzad

    2014-10-01

    Accumulation of hydrogen during anaerobic processes usually results in low decomposition of volatile organic acids (VFAs). On the other hand, hydrogen is a good electron donor for dye reduction, which would help the acetogenic conversion in keeping low hydrogen concentration. The main objective of the study was to accelerate VFA composition through using azo dye as electron acceptor. The results indicated that the azo dye serving as an electron acceptor could avoid H2 accumulation and accelerate anaerobic digestion of VFAs. After adding the azo dye, propionate decreased from 2400.0 to 689.5mg/L and acetate production increased from 180.0 to 519.5mg/L. It meant that the conversion of propionate into acetate was enhanced. Fluorescence in situ hybridization analysis showed that the abundance of propionate-utilizing acetogens with the presence of azo dye was greater than that in a reference without azo dye. The experiments via using glucose as the substrate further demonstrated that the VFA decomposition and the chemical oxygen demand (COD) removal increased by 319.7mg/L and 23.3% respectively after adding the azo dye. Therefore, adding moderate azo dye might be a way to recover anaerobic system from deterioration due to the accumulation of H2 or VFAs.

  12. Advanced oxidation processes in azo dye wastewater treatment.

    PubMed

    Papić, Sanja; Koprivanac, Natalija; Bozić, Ana Loncarić; Vujević, Dinko; Dragicević, Savka Kusar; Kusić, Hrvoje; Peternel, Igor

    2006-06-01

    The chemical degradation of synthetic azo dyes color index (C.I.) Acid Orange 7, C.I. Direct Orange 39, and C.I. Mordant Yellow 10 has been studied by the following advanced oxidation processes: Fenton, Fenton-like, ozonation, peroxone without or with addition of solid particles, zeolites HY, and NH4ZSM5. Spectrophotometric (UV/visible light spectrum) and total organic carbon measurements were used for determination of process efficiency and reaction kinetics. The degradation rates are evaluated by determining their rate constants. The different hydroxyl radical generation processes were comparatively studied, and the most efficient experimental conditions for the degradation of organic azo dyes solutions were determined.

  13. 40 CFR 721.5917 - Phenyl azo dye (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phenyl azo dye (generic). 721.5917... Substances § 721.5917 Phenyl azo dye (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a phenyl azo dye (PMN P-02-17) is subject...

  14. 40 CFR 721.5917 - Phenyl azo dye (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phenyl azo dye (generic). 721.5917... Substances § 721.5917 Phenyl azo dye (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a phenyl azo dye (PMN P-02-17) is subject...

  15. 40 CFR 721.5917 - Phenyl azo dye (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phenyl azo dye (generic). 721.5917... Substances § 721.5917 Phenyl azo dye (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a phenyl azo dye (PMN P-02-17) is subject...

  16. 40 CFR 721.5917 - Phenyl azo dye (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phenyl azo dye (generic). 721.5917... Substances § 721.5917 Phenyl azo dye (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a phenyl azo dye (PMN P-02-17) is subject...

  17. 40 CFR 721.5917 - Phenyl azo dye (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phenyl azo dye (generic). 721.5917... Substances § 721.5917 Phenyl azo dye (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a phenyl azo dye (PMN P-02-17) is subject...

  18. Reductive behaviour of acid azo dye based wastewater: Biocatalyst activity in conjunction with enzymatic and bio-electro catalytic evaluation.

    PubMed

    Sreelatha, S; Nagendranatha Reddy, C; Velvizhi, G; Venkata Mohan, S

    2015-01-01

    Present study illustrates the significance of biocatalyst's reductive behaviour in the degradation of dye molecules using glucose as co-substrate. An anaerobic system was operated at a dye concentration of 50mg/l with an organic loading rate (OLR) of 1.36 kg COD/m(3)-day. Decolourization and COD removal efficiencies were observed to be 42% and 48% respectively. Azo reductase (18.9 U) and dehydrogenase enzyme (1.4 μg/ml) activities showed increment with operation time. Anaerobic microenvironment showed dye reduction converting them into aromatic amines. The presence of mediators viz., cytochromes, quinines and Fe-S proteins depicted in the cyclic voltammetry profiles played a crucial role in transfer of electrons for the reduction of dye molecules. Bio-electro kinetic profiles obtained through Tafel analysis showed persistent reduction behaviour, which is in good correlation with dye degradation in the anaerobic microenvironment.

  19. A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye--Acid Blue 113.

    PubMed

    Gupta, V K; Gupta, Bina; Rastogi, Arshi; Agarwal, Shilpi; Nayak, Arunima

    2011-02-15

    A mesoporous carbon developed from waste tire rubber, characterized by chemical analysis, FTIR, and SEM studies, was used as an adsorbent for the removal and recovery of a hazardous azo dye, Acid Blue 113. Surface area, porosity, and density were determined. The adsorption of the dye over the prepared adsorbent and a commercial activated carbon was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature conditions. Langmuir and Freundlich adsorption isotherm models were applied and thermodynamic parameters were calculated. Kinetic studies indicated that the adsorption process follow first order kinetics and particle diffusion mechanisms are operative. By percolating the dye solution through fixed-bed columns the bulk removal of the Acid Blue 113 was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of the dye was made by eluting 0.1 M NaOH through the column.

  20. Anaerobic/aerobic treatment of selected azo dyes in wastewater

    SciTech Connect

    Seshadri, S.; Bishop, P.L. . Dept. of Civil and Environmental Engineering); Agha, A.M. . Faculty of Civil Engineering)

    1994-01-01

    Azo dyes represent the largest class of dyes in use today. Current environmental concern with these dyes revolves around the potential carcinogenic health risk presented by these dyes or their intermediate biodegradation products when exposed to microflora in the human digestive tract. These dyes may build up in the environment, since many wastewater treatment plants allow these dyes to pass through the system virtually untreated. The initial step in the degradation of these dyes is the cleavage of the Azo bond. This cleavage is often impossible under aerobic conditions, but has been readily demonstrated under anaerobic conditions. The focus of the study was to determine the feasibility of using an anaerobic fluidized-bed reactor to accomplish this cleavage. The effects of typical process variables such as hydraulic retention time (HRT), influent dye concentration levels, and degree of bed fluidization on removal efficiencies were also studied. The four dyes selected for this study were Acid-Orange 7, Acid-Orange 8, Acid-Orange 10, and Acid-Red 14. The effectiveness of using a bench-scale-activated sludge reactor as a sequenced second stage was also examined. Results indicate that nearly complete cleavage of the Azo bond is easily accomplished for each of the four dyes under hydraulic retention times of either 12 or 24 h. Initial results indicate, though, that aromatic amine by-products remain. The sequenced second stage was able to remove the remaining Chemical Oxygen Demand (COD) load to acceptable levels. Work is presently underway to determine the face of the anaerobic by-products in the aerobic second stage.

  1. Environmental photochemistry on semiconductor surfaces: Photosensitized degradation of a textile azo dye, Acid Orange 7, on TiO{sub 2} particles using visible light

    SciTech Connect

    Vinodgopal, K.; Wynkoop, D.E.; Kamat, P.V.

    1996-05-01

    Photosensitized degradation of a textile azo dye, Acid Orange 7, has been carried out on TiO{sub 2} particles using visible light. Mechanistic details of the dye degradation have been elucidated using diffuse reflectance absorption and FTIR techniques. Degradation does not occur on Al{sub 2}O{sub 3} surface or in the absence of oxygen. The dependence of the dye degradation rate on the surface coverage shows the participation of excited dye and TiO{sub 2} semiconductor in the surface photochemical process. Diffuse reflectance laser flash photolysis confirms the charge injection from the excited dye molecule into the conduction band of the semiconductor as the primary mechanism for producing oxidized dye radical. The surface-adsorbed oxygen plays an important role in scavenging photogenerated electrons, thus preventing the recombination between the oxidized dye radical and the photoinjected electrons. Diffuse reflectance FTIR was used to make a tentative identification of reaction intermediates and end products of dye degradation. The intermediates, 1,2-naphthoquinone and phthalic acid, have been identified during the course of degradation. Though less explored in photocatalysis, the photosensitization approach could be an excellent choice for the degradation of colored pollutants using visible light. 51 refs., 10 figs.

  2. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  3. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  4. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  5. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  6. 40 CFR 721.4594 - Substituted azo metal complex dye.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted azo metal complex dye. 721... Substances § 721.4594 Substituted azo metal complex dye. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a substituted azo metal...

  7. Application of acidic treated pumice as an adsorbent for the removal of azo dye from aqueous solutions: kinetic, equilibrium and thermodynamic studies.

    PubMed

    Samarghandi, Mohammad Reza; Zarrabi, Mansur; Sepehr, Mohammad Noori; Amrane, Abdeltif; Safari, Gholam Hossein; Bashiri, Saied

    2012-11-05

    Colored effluents are one of the important environment pollution sources since they contain unused dye compounds which are toxic and less-biodegradable. In this work removal of Acid Red 14 and Acid Red 18 azo dyes was investigated by acidic treated pumice stone as an efficient adsorbent at various experimental conditions. Removal of dye increased with increase in contact time and initial dye concentration, while decreased for increment in solution temperature and pH. Results of the equilibrium study showed that the removal of AR14 and AR18 followed Freundlich (r2>0.99) and Langmuir (r2>0.99) isotherm models. Maximum sorption capacities were 3.1 and 29.7 mg/g for AR 14 and AR18, namely significantly higher than those reported in the literature, even for activated carbon. Fitting of experimental data onto kinetic models showed the relevance of the pseudo-second order (r2>0.99) and intra-particle diffusion (r2>0.98) models for AR14 and AR18, respectively. For both dyes, the values of external mass transfer coefficient decreased for increasing initial dye concentrations, showing increasing external mass transfer resistance at solid/liquid layer. Desorption experiments confirmed the relevance of pumice stone for dye removal, since the pH regeneration method showed 86% and 89% regeneration for AR14 and AR18, respectively.

  8. Application of acidic treated pumice as an adsorbent for the removal of azo dye from aqueous solutions: kinetic, equilibrium and thermodynamic studies

    PubMed Central

    2012-01-01

    Colored effluents are one of the important environment pollution sources since they contain unused dye compounds which are toxic and less-biodegradable. In this work removal of Acid Red 14 and Acid Red 18 azo dyes was investigated by acidic treated pumice stone as an efficient adsorbent at various experimental conditions. Removal of dye increased with increase in contact time and initial dye concentration, while decreased for increment in solution temperature and pH. Results of the equilibrium study showed that the removal of AR14 and AR18 followed Freundlich (r2>0.99) and Langmuir (r2>0.99) isotherm models. Maximum sorption capacities were 3.1 and 29.7 mg/g for AR 14 and AR18, namely significantly higher than those reported in the literature, even for activated carbon. Fitting of experimental data onto kinetic models showed the relevance of the pseudo-second order (r2>0.99) and intra-particle diffusion (r2>0.98) models for AR14 and AR18, respectively. For both dyes, the values of external mass transfer coefficient decreased for increasing initial dye concentrations, showing increasing external mass transfer resistance at solid/liquid layer. Desorption experiments confirmed the relevance of pumice stone for dye removal, since the pH regeneration method showed 86% and 89% regeneration for AR14 and AR18, respectively. PMID:23369579

  9. Comprehensive review and compilation of treatment for azo dyes using microbial fuel cells.

    PubMed

    Murali, V; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Hamidin, Nasrul

    2013-03-01

    Microbial fuel cells (MFCs) represent an emerging technology that focuses on power generation and effluent treatment. This review compiles articles related to MFCs using azo dye as the substrate. The significance of the general components in MFCs and systems of MFCs treating azo dye is depicted in this review. In addition, degradation of azo dyes such as Congo red, methyl orange, active brilliant red X-3B, amaranth, reactive blue 221, and acid orange 7 in MFCs are summarized. Further exploration and operational modification are suggested to address the challenges of complete removal of azo dye with maximum power generation in an MFC. In addition, a sequential treatment system with MFCs is suggested for complete mineralization of azo dye.

  10. Degradation of azo dyes by environmental microorganisms and helminths

    SciTech Connect

    Kingthom Chung; Stevens, S.E. Jr. . Dept. of Biology)

    1993-11-01

    The degradation of azo dyes by environmental microorganisms, fungi, and helminths is reviewed. Azo dyes are used in a wide variety of products and can be found in the effluent of most sewage treatment facilities. Substantial quantities of these dyes have been deposited in the environment, particularly in streams and rivers. Azo dyes were shown to affect microbial activities and microbial population sizes in the sediments and in the water columns of aquatic habitats. Only a few aerobic bacteria have been found to reduce azo dyes under aerobic conditions, and little is known about the process. A substantial number of anaerobic bacteria capable of azo dye reduction have been reported. The enzyme responsible for azo dye reduction has been partially purified, and characterization of the enzyme is proceeding. The nematode Ascaris lumbricoides and the cestode Moniezia expanza have been reported to reduce azo dyes anaerobically. Recently the fungus Phanerochaete chrysoporium was reported to mineralize azo dyes via a peroxidation-mediated pathway. A possible degradation pathway for the mineralization of azo dye is proposed and future research needs are discussed.

  11. 40 CFR 721.9717 - Azo monochloro triazine reactive dye.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Azo monochloro triazine reactive dye... Substances § 721.9717 Azo monochloro triazine reactive dye. (a) Chemical substance and significant new uses... reactive dye (PMN P-96-238) is subject to reporting under this section for the significant new...

  12. 40 CFR 721.9717 - Azo monochloro triazine reactive dye.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Azo monochloro triazine reactive dye... Substances § 721.9717 Azo monochloro triazine reactive dye. (a) Chemical substance and significant new uses... reactive dye (PMN P-96-238) is subject to reporting under this section for the significant new...

  13. 40 CFR 721.9717 - Azo monochloro triazine reactive dye.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Azo monochloro triazine reactive dye... Substances § 721.9717 Azo monochloro triazine reactive dye. (a) Chemical substance and significant new uses... reactive dye (PMN P-96-238) is subject to reporting under this section for the significant new...

  14. 40 CFR 721.9717 - Azo monochloro triazine reactive dye.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Azo monochloro triazine reactive dye... Substances § 721.9717 Azo monochloro triazine reactive dye. (a) Chemical substance and significant new uses... reactive dye (PMN P-96-238) is subject to reporting under this section for the significant new...

  15. 40 CFR 721.9717 - Azo monochloro triazine reactive dye.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Azo monochloro triazine reactive dye... Substances § 721.9717 Azo monochloro triazine reactive dye. (a) Chemical substance and significant new uses... reactive dye (PMN P-96-238) is subject to reporting under this section for the significant new...

  16. REDUCTION OF AZO DYES WITH ZERO-VALENT IRON. (R827117)

    EPA Science Inventory

    The reduction of azo dyes by zero-valent iron metal (Fe0) at pH 7.0 in 10 mM HEPES buffer was studied in aqueous, anaerobic batch systems. Orange II was reduced by cleavage of the azo linkage, as evidenced by the production of sulfanilic acid (a substituted ani...

  17. Electroenzymatic degradation of azo dye using an immobilized peroxidase enzyme.

    PubMed

    Kim, Gha-Young; Lee, Ki-Beom; Cho, Seung-Hee; Shim, Joonmok; Moon, Seung-Hyeon

    2005-11-11

    Azo dyes are largely resistant to biodegradation and persist in conventional wastewater treatment processes. Combining enzymatic catalysis and the electrochemical generation of hydrogen peroxide (H2O2), an electroenzymatic process was developed, which is a potential alternative to traditional processes. In this study, an electroenzymatic method that uses an immobilized horseradish peroxidase enzyme (HRP), was investigated to degrade orange II (azo dye) within a two-compartment packed-bed flow reactor. To evaluate the electroenzymatic degradation of orange II, electrolytic experiments were carried out with 0.42 U/mL HRP at -0.5 V. It was found that removal of orange II was partly due to its adsorption to the graphite felt. The overall application of the electroenzymatic led to a greater degradation rate than the use of electrolysis alone. Also the by-products formed were found to consist primarily of an aromatic amine, sulfanilic acid, and unknown compounds.

  18. Integration of nanosized zero-valent iron particles addition with UV/H2O2 process for purification of azo dye Acid Black 24 solution.

    PubMed

    Shu, Hung-Yee; Chang, Ming-Chin; Chang, Chi-Chen

    2009-08-15

    The challenging national effluent standards for color and organic concentration enforce the industrial concern most the techniques providing fast and efficient solution for the strenuous dye wastewater treatment before outflow. The best remediation technique pursuit is urgently demand for the industrial, government, academia and community. In this study, a di-azo dye, C.I. Acid Black 24, synthesized wastewater was successfully removed synchronously its total color and total organic carbon (TOC) using an integrated innovation technology by coupling the zero-valent iron (ZVI) nanoparticles with UV/H(2)O(2) oxidation process. The nanosized ZVI (NZVI) primarily reduced color successfully following coupling UV/H(2)O(2) oxidation process for the residual organic mineralization resulting reduction with oxidation process (Re-Ox) for total color removal and organic mineralization. From the experimental data, the Re-Ox process consumed shorter time than UV/H(2)O(2) oxidation process alone to obtain total color removal of dye wastewater. Moreover, the residual TOC of dye wastewater after NZVI reduction from 45 to 100% was effectively mineralized by UV/H(2)O(2) process. By using proposed processes integration with NZVI dosage of 0.3348 g l(-1) and hydrogen peroxide concentration of 23.2 mM, in only 10 min the AB24 color was complete eliminated and in 90 min the TOC was 93.9% removed. Thus, the coupling Re-Ox process was developed to provide a superior solution for dye wastewater treatment.

  19. An Interdisciplinary Experiment: Azo-Dye Metabolism by "Staphylococcus Aureus"

    ERIC Educational Resources Information Center

    Brocklesby, Kayleigh; Smith, Robert; Sharp, Duncan

    2012-01-01

    An interdisciplinary and engaging practical is detailed which offers great versatility in the study of a qualitative and quantitative metabolism of azo-dyes by "Staphylococcus aureus". This practical has broad scope for adaptation in the number and depth of variables to allow a focused practical experiment or small research project. Azo-dyes are…

  20. The role of the medium on the acid dissociation constants of some azo dyes in view of experimental and theoretical data

    NASA Astrophysics Data System (ADS)

    Ebead, Y. H.

    2010-10-01

    In this study, the p Ka values of some azo dyes derived from cyclohexane-1,3-dione in different organic solvent + water mixtures have been determined spectrophotometrically. The organic solvents used are ethanol, acetone and N, N-dimethylformamide (DMF). Thus, the nature and the proportion of the organic cosolvent effects as well as the molecular structure on acidity constants were evaluated. Furthermore, the proton-donating ability of N 10H reflected by thermodynamic parameters - Δ f,298Ho, Δ 298So and Δ f,298Go - for compounds 1- 4 has been estimated using AM1and PM6 methods in the gas and aqueous phases. The data obtained provides a complete and accurate picture of the acid-base properties of the compounds under study. The p Ka values predicted in aqueous phase by the previous methods were compared with the experimental values and the best agreement with the experimental data was obtained by AM1.

  1. Mineralization of C.I. Acid Red 14 azo dye by UV/Fe-ZSM5/H2O2, process.

    PubMed

    Kasiri, Masoud B; Aleboyeh, Hamid; Aleboyeh, Azam

    2010-02-01

    The zeolite Fe-ZSM5 was applied as a heterogeneous catalyst in the photo-Fenton process for mineralization of azo dye Acid Red 14 (AR14). Under optimal conditions (20 mM of H2O2 0.25 g L(-1) of catalyst and initial natural pH of the solution) 76% of total organic carbon (TOC) of a solution containing 40 mg L(-1) of the dye could be removed after 120 min in a 1.0 L tubular, closed-circulation batch photoreactor. Leaching tests and comparative experiments indicated that the application of the heterogeneous catalyst could increase the photo-Fenton process efficiency. A kinetic model was developed for this process and showed that the dye mineralization rate obeyed the pseudo-first order kinetic when the initial concentration of the dye was low. It was also observed that the catalytic behaviour of Fe-ZSM5 could be reproduced in consecutive experiments without a considerable drop in the process efficiency. Estimation of electrical energy consumption (EE/O) of the process as a function of mineralization efficiency revealed that the UV/Fe-ZSM5/H2O2 process not only increased the mineralization efficiency of the process, but also decreased the cost of electrical energy consumed by the process.

  2. Decolorization of azo dye acid black 1 by the UV/H2O2 process and optimization of operating parameters.

    PubMed

    Shu, Hung-Yee; Chang, Ming-Chin; Fan, Huan-Jung

    2004-09-10

    An advanced oxidation process, UV/H2O2, was applied for decolorization of a di-azo dye (acid black 1). The effects of operating parameters such as hydrogen peroxide dosage, UV dosage and initial dye concentration, on decolorization have been evaluated. The acid black 1 solution was completely decolorized under optimal hydrogen peroxide dosage of 21.24 mmol/l and UV dosage of 1400 W/l in less than 1.2 min. The decolorization rate followed pseudo-first order kinetics with respect to the dye concentration. The rate increased linearly with volumetric UV dosage and nonlinearly with increasing initial hydrogen peroxide concentration. It has been found that the degradation rate increased until an optimum of hydrogen peroxide dosage, beyond which the reagent exerted an inhibitory effect. For real case application, an operation parameter plot of rate constant was developed. To evaluate the electric power and hydrogen peroxide consumption by UV/H2O2 reactor, 90% color removal was set as criteria to find the balance between both factors.

  3. Performance of mango seed adsorbents in the adsorption of anthraquinone and azo acid dyes in single and binary aqueous solutions.

    PubMed

    Dávila-Jiménez, Martín M; Elizalde-González, María P; Hernández-Montoya, Virginia

    2009-12-01

    In this study the husk of mango seed and two carbonaceous adsorbents prepared from it were used to study the adsorption behavior of eight acid dyes. The adsorbed amount in mmol m(-2) decayed asymptotically as the molecular volume and area increased. The interaction between the studied dyes and the mesoporous carbon was governed by the ionic species in solution and the acidic/basic groups on the surface. Less than 50% of the external surface of the microporous carbon became covered with the dyes molecules, though monolayer formation demonstrating specific interactions only with active sites on the surface and the adsorption magnitudes correlated with the shape parameter of the molecule within a particular dye group. The adsorption behavior in mixtures was determined by the molecular volume of the constituents; the greater the molecular volume difference, the greater the effect on the adsorbed amount. We also demonstrated that the raw husk of the mango seed can be used to remove up to 50% from model 50 mg l(-1) solutions of the studied acid dyes.

  4. Treatment of azo dye-containing synthetic textile dye effluent using sulfidogenic anaerobic baffled reactor.

    PubMed

    Ozdemir, Sebnem; Cirik, Kevser; Akman, Dilek; Sahinkaya, Erkan; Cinar, Ozer

    2013-10-01

    This study aims at investigating azo dye reduction performance of a sulfidogenic anaerobic baffled reactor (ABR) for around 400 days. ABR was operated at 30 °C in a temperature-controlled room and hydraulic retention time (HRT) was kept constant at 2 days. The robustness of ABR was assessed under varying azo dye loadings and COD/sulfate ratios. Additionally, oxygen was supplied (1-2 L air/m(3)reactor min) to the last compartment to investigate the removal of azo dye breakdown products. ABR performed well in terms of COD, sulfate and azo dye removals throughout the reactor operation. Maximum azo dye, COD and sulfate removals were 98%, 98% and 93%, respectively, at COD/sulfate ratio of 0.8. Aeration created different redox conditions in last compartment, which enhanced the removal of COD and breakdown products. The adverse effects of aeration on azo dye reduction were eliminated thanks to the compartmentalized structure of the ABR.

  5. Photoinduced ordering and anchoring properties of azo-dye films.

    PubMed

    Kiselev, Alexei D; Chigrinov, Vladimir; Huang, Dan Ding

    2005-12-01

    We study both theoretically and experimentally the anchoring properties of photoaligning azo-dye films in contact with a nematic liquid crystal depending on the photoinduced ordering of azo-dye molecules. In the mean field approximation, we found that the bare surface anchoring energy depends linearly on the azo-dye order parameter and the azimuthal anchoring strength decays to zero in the limit of vanishing photoinduced ordering. From the absorption dichroism spectra measured in azo-dye films that are prepared from an azo-dye derivative with polymerizable terminal groups we obtain the dependence of the dichroic ratio on the irradiation dose. We also measure the polar and azimuthal anchoring strengths in nematic liquid crystal (NLC) cells aligned by the azo-dye films and derive the anchoring strengths as functions of the dichroic ratio, which is proportional to the photoinduced order parameter. Although linear fitting of the experimental data for both anchoring strengths gives reasonable results, it, predicts vanishing of the azimuthal anchoring strength at some nonzero value of the azo-dye order parameter, in contradiction with theory. By using a simple phenomenological model we show that this discrepancy can be attributed to the difference between the surface and bulk order parameters in the films. The measured polar anchoring energy is found to be an order of magnitude higher than the azimuthal strength. Our theory suggests that the quadrupole term of the spherical harmonics expansion for the azo-dye-NLC intermolecular potential might be of importance for the understanding of this difference.

  6. Photobleaching effect in azo-dye containing epoxy resin films: the potentiality of carbon nanotubes as azo-dye dispensers

    NASA Astrophysics Data System (ADS)

    Díaz Costanzo, Guadalupe; Goyanes, Silvia; Ledesma, Silvia

    2015-04-01

    Azo-dye molecules may suffer from bleaching under certain illumination conditions. When this photoinduced process occurs, it generates an irreversible effect that is characterized by the loss of absorption of the dye molecule. Moreover, the well-known isomerization of azodye molecules does not occur anymore. In this work it is shown how the addition of a small amount of multi-walled carbon nanotubes (MWCNTs) helps to decrease the bleaching effect in a photosensitive guest-host azo-polymer film. Two different systems were fabricated using an epoxy resin as polymer matrix. An azo-dye, Disperse Orange 3, was used as photosensitive material in both systems and MWCNTs were added into one of them. The optical response of the polymeric systems was studied considering the degree of photoinduced birefringence. Photobleaching of the azo-dye was observed in all cases however, the effect is lower for the composite material containing 0.2 wt % MWCNTs. The weak interaction between MWCNTs and dye molecules is less favorable when the material is heated. The optical behavior of the heated composite material suggests that carbon nanotubes can be potentially used as azo dye dispensers. The results are interpreted in terms of the non-covalent interaction between azo-dye molecules and MWCNTs.

  7. Preparation of ZnO Photocatalyst for the Efficient and Rapid Photocatalytic Degradation of Azo Dyes

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqing; Wu, Zhansheng; Liu, Dandan; Gao, Zhenzhen

    2017-02-01

    Zinc oxide (ZnO) photocatalysts were synthesized by sol-gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO prepared with a composite ratio of 4:1 and calcination temperature of 400 °C exhibited 99.70% removal rate for MO. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of azo dyes increased with the increased dosage of catalyst and decreased initial concentration of azo dyes and the acidic condition is favorable for degradation. Furthermore, the kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of azo dyes fitted the first-order kinetics and superoxide ions were the main species. The proposed photocatalyst can efficiently and rapidly degrade azo dyes; thus, this economical and environment-friendly photocatalyst can be applied to the treatment of wastewater contaminated with synthetic dyes.

  8. Preparation of ZnO Photocatalyst for the Efficient and Rapid Photocatalytic Degradation of Azo Dyes.

    PubMed

    Chen, Xiaoqing; Wu, Zhansheng; Liu, Dandan; Gao, Zhenzhen

    2017-12-01

    Zinc oxide (ZnO) photocatalysts were synthesized by sol-gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO prepared with a composite ratio of 4:1 and calcination temperature of 400 °C exhibited 99.70% removal rate for MO. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of azo dyes increased with the increased dosage of catalyst and decreased initial concentration of azo dyes and the acidic condition is favorable for degradation. Furthermore, the kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of azo dyes fitted the first-order kinetics and superoxide ions were the main species. The proposed photocatalyst can efficiently and rapidly degrade azo dyes; thus, this economical and environment-friendly photocatalyst can be applied to the treatment of wastewater contaminated with synthetic dyes.

  9. Oxidative treatment of azo dyes in aqueous solution by potassium permanganate.

    PubMed

    Aleboyeh, A; Olya, M E; Aleboyeh, H

    2009-03-15

    This work was conducted to study the ability of permanganate (KMnO(4)) oxidative treatment as a method to decolourise the solutions containing azo dye C.I. Acid Orange 7, C.I. Acid Orange 8, C.I. Acid Red 14, or C.I. Acid Red 73, in a batch system. The results of the study demonstrated the complete removal of the colour and partial mineralization for each dye solution. The effect of the key operating variables such as initial dye concentration, permanganate amount, pH and temperature were studied. Decolourisation reactions were influenced by the acidity and temperature of the treated solutions. To avoid the overdose of KMnO(4), the stoichiometric amount of permanganate required for 1 mol of dye complete colour removal was determined. The reactions between permanganate and C.I. Acid Orange 7, C.I. Acid Orange 8, C.I. Acid Red 14 and C.I. Acid Red 73 dyes in acidic medium exhibit (2.05, 2.20, 2.42 and 2.79):1 stoichiometry (MnO(4)(-):dye). Dye degradation efficiency by potassium permanganate was studied, monitoring total organic carbon (TOC). The results indicated that the degradation efficiency of azo dyes increased with the increase of the potassium permanganate amount. Meanwhile, even in large excess of the oxidant, the dye mineralization was incomplete.

  10. Growth and physiology of Clostridium perfringens wild-type and ΔazoC knockout: an azo dye exposure study.

    PubMed

    Morrison, Jessica M; John, Gilbert H

    2016-02-01

    Clostridium perfringens, a strictly anaerobic micro-organism and inhabitant of the human intestine, has been shown to produce the azoreductase enzyme AzoC, an NAD(P)H-dependent flavin oxidoreductase. This enzyme reduces azo dyes to aromatic amines, which are carcinogenic in nature. A significant amount of work has been completed that focuses on the activity of this enzyme; however, few studies have been completed that focus on the physiology of azo dye reduction. Dye reduction studies coupled with C. perfringens growth studies in the presence of ten different azo dyes and in media of varying complexities were completed to compare the growth rates and dye-reducing activity of C. perfringens WT cells, a C. perfringens ΔazoC knockout, and Bifidobacterium infantis, a non-azoreductase-producing control bacterium. The presence of azo dyes significantly increased the generation time of C. perfringens in rich medium, an effect that was not seen in minimal medium. In addition, azo dye reduction studies with the ΔazoC knockout suggested the presence of additional functional azoreductases in this medically important bacterium. Overall, this study addresses a major gap in the literature by providing the first look, to our knowledge, at the complex physiology of C. perfringens upon azo dye exposure and the effect that both azo dyes and the azoreductase enzyme have on growth.

  11. Degradation of azo dyes by oxidative processes--laccase and ultrasound treatment.

    PubMed

    Tauber, Michael M; Gübitz, Georg M; Rehorek, Astrid

    2008-07-01

    Azo dyes are of synthetic origin and their environmental fate is not well understood. They are resistant to direct aerobic bacterial degradation and form potentially carcinogenic aromatic amines by reduction of the azo group. This study shows that applying the oxidative processes of enzymatic treatment with laccase and ultrasound treatment, both alone and in combination, leads to dye degradation. Laccase treatment degraded both Acid Orange and Direct Blue dyes within 1-5 h but failed in the case of Reactive dyes, whereas ultrasound degraded all the dyes investigated (3-15 h). When applied as multi-stage combinations the treatments showed synergistic effects for dye degradation compared with individual treatments. Bulk light absorption (UV-Vis) and ion pairing HPLC were used for process monitoring. Additionally, mass spectrometry was used to elucidate the structures of intermediates arising from ultrasound treatment.

  12. Kinetics of azoreductase and assessment of toxicity of metabolic products from azo dyes by Pseudomonas luteola.

    PubMed

    Hu, T L

    2001-01-01

    This is a continuous study on a decolorization strain, Pseudomonas luteola, which involves treating seven azo dyes with different structures. This study focuses mainly on determining both the mechanism of decolorization by P. luteola and the activity of azoreductase from P. luteola as well as identifying and assessing the toxicity of metabolic products of azo dyes. The growth of P. luteola reached the stationary phase after shaking incubation for 24 hours. Then, while being kept static, the color of seven tested azo dyes (100 mg/l) could be removed. The proportion of color removal was between 59-99%, which figure is related to the structure of the dye. Monoazo dyes (RP2B, V2RP and Red 22) showed the fastest rate of decolorization, i.e. from 0.23-0.44 mg dye-mg cell-1 hr-1. P. luteola could remove the color of V2RP and a leather dye at a concentration of 200 mg/l, and as to the rest of the azo dyes, it could remove at a concentration of up to 100 mg/l. Decolorization of RP2B and Red 22 required activation energy of 7.00 J/mol and 6.63 J/mole, respectively, indicating that it was easier for azoreductase to decolorize structurally simple dyes. The kinetics of azoreductase towards seven azo dyes suggested a competitive inhibition model be applied. Microtox was used to analyze the toxicity of the metabolic products of azo dyes. EC50 showed differences in toxicity before and after the azo dyes had been metabolized. Analysis revealed significant differences between the results obtained by EC50 with Blue 15 and those obtained with the leather dye, indicating that the toxicities of the metabolic products were increased. The differences obtained by EC50 with Red 22, RP2P and V2RP were small, and Black 22 showed no such difference. Sulfanic acid and orthanilic acid may be the intermediate products of Violet 9 and RP2B, respectively. However, according to FT-IR analysis, aromatic amines were present in the metabolic product.

  13. Azo dye decolorization by a new fungal isolate, Penicillium sp. QQ and fungal-bacterial cocultures.

    PubMed

    Gou, Min; Qu, Yuanyuan; Zhou, Jiti; Ma, Fang; Tan, Liang

    2009-10-15

    A new azo dyes-decolorizing fungi strain QQ was isolated from activated sludge. It was identified as Penicillium sp. based on 26S rRNA gene sequence analysis. The study indicated that strain QQ could aerobically decolorize Reactive Brilliant Red X-3B by the way of bioadsorption, and nutrient-poor medium was more beneficial for adsorption. Decolorization rate was inversely proportional to the size of mycelial pellets. The optimum pH was observed at 4 or 5 for X-3B decolorization. There was still 70% color removal when salinity increased to 6%. By contrast with aerobic decolorization, the degradation of azo dyes occurred under anaerobic conditions, and some azo dyes could be absolutely decolorized. Furthermore, the decolorization of azo dyes by fungal-bacterial cocultures was investigated. The results demonstrated that strain QQ and Sphingomonas xenophaga QYY cocultures performed better than any single strain did. Weak acidity conditions and the presence of small amount of surfactant could enhance the ability of consortium to decolorize azo dyes.

  14. Zero-valent iron pretreatment for enhancing the biodegradability of Azo dyes.

    PubMed

    Perey, Jennie R; Chiu, Pei C; Huang, Chin-Pao; Cha, Daniel K

    2002-01-01

    Azo dyes are a group of chemicals that are largely resistant to aerobic biodegradation and persist in wastewater treatment processes. This study proposed that zero-valent iron can be used to reduce the azo bond, cleaving the dye molecule into products that are more amenable to mineralization by bacteria in biological treatment processes such as activated sludge. Batch anaerobic reduction experiments were performed using two azo dyes, orange G and orange II, to determine reaction kinetics and to identify reduction products. Iron-treated dye solutions were subjected to batch biodegradation tests and respirometric analyses to screen for enhanced biodegradability over parent dyes. Results indicate that treatment of orange G and orange II with scrap iron produces aniline and sulfanilic acid as significant products that are degraded by an acclimated culture within 24 hours. Respirometric data illustrated that iron-treated dye solutions exert a significantly higher biochemical oxygen demand than the solutions containing orange G and orange II, demonstrating that recalcitrant azo dyes can be aerobically biodegraded after iron pretreatment.

  15. Reduction and partial degradation mechanisms of naphthylaminesulfonic azo dye amaranth by Shewanella decolorationis S12.

    PubMed

    Hong, Yiguo; Guo, Jun; Xu, Zhicheng; Mo, Cuiyun; Xu, Meiying; Sun, Guoping

    2007-06-01

    Reduction and biodegradation mechanisms of naphthylaminesulfonic azo dye amaranth using a newly isolated Shewanella decolorationis strain S12 were investigated. Under anaerobic conditions, amaranth was reduced by strain S12, and a stoichiometric amount of two reduction products RP-1 and RP-2 were generated. UV/visible spectrophotometric and high performance liquid chromatography (HPLC) analysis indicated that RP-1 and RP-2 were 1-aminenaphthylene -4-sulfonic acid and 1-aminenaphthylene-2-hydroxy-3, 6-disulfonic acid. The result strongly supports a mechanism of azo dye reduction by the process via the reductive cleavage of the azo bond to form corresponding aromatic amines. The result of HPLC analyses revealed that these aromatic amines were not able to be mineralized by strain S12 under anaerobic conditions. But after re-aeration of the decolorized culture, RP-2 was mineralized completely by this microorganism, but the consumption of RP-1 was not observed. Ames test showed that amaranth had mutagenic but no cytotoxic potential. The mutagenic potential was relieved after the anaerobic treatment with strain S12 as the mutagenic effect of the two reduction products from amaranth was not detected by Ames test. Thus, the ability of strain S12 to reduce and partially mineralize the naphthylaminesulfonic azo dye efficiently was demonstrated, which can potentially be used to biodegrade and detoxify wastewater containing azo dyes using an alternating anaerobic/aerobic treatment procedure.

  16. Biosorption of Azo dyes by spent Rhizopus arrhizus biomass

    NASA Astrophysics Data System (ADS)

    Salvi, Neeta A.; Chattopadhyay, S.

    2016-05-01

    In the present study, spent Rhizopus arrhizus biomass was used for the removal of six azo dyes from aqueous solutions. The dye removal capacity of the biomass was evaluated by conducting batch tests as a function of contact time, biomass dosage, pH and initial dye concentrations. The pseudo-second-order kinetic model fitted well with the experimental data with correlation coefficients greater than 0.999, suggesting that chemisorptions might be the rate limiting step. The equilibrium sorption data showed good fit to the Langmuir isotherm model. Among the six dyes tested, the maximum monolayer adsorption capacity for fast red A and metanil yellow was found to be 108.8 and 128.5 mg/g, respectively. These encouraging results suggest that dead Rhizopus arrhizus biomass could be a potential biomaterial for the removal of azo dyes from aqueous dye solution.

  17. Degradation efficiencies of azo dye Acid Orange 7 by the interaction of heat, UV and anions with common oxidants: persulfate, peroxymonosulfate and hydrogen peroxide.

    PubMed

    Yang, Shiying; Wang, Ping; Yang, Xin; Shan, Liang; Zhang, Wenyi; Shao, Xueting; Niu, Rui

    2010-07-15

    In this paper, the degradation of azo dye Acid Orange 7 (AO7) by three common peroxides (persulfate (PS), peroxymonosulfate (PMS) or hydrogen peroxide (H(2)O(2))) under various activation conditions, i.e., heat (25-80 degrees C), UV light (254 nm), or anions (SO(4)(2-), NO(3)(-), CO(3)(2-), HCO(3)(-), HPO(4)(2-), and Cl(-)), was investigated. The order of AO7 degradation efficiencies by heat activation is PS>PMS>H(2)O(2). PS oxidation activated by heat (>50 degrees C) is an effective degradation technology, while PMS and H(2)O(2) are hardly activated. When assisted by UV, peroxides could all be activated and degrade AO7 quickly. The order is PS>H(2)O(2)>PMS. We activated peroxides, for the first time, by using some anions and compared the subsequently degradation efficiencies of AO7. It was found that PMS could be activated by some anions, but PS and H(2)O(2) cannot. The activation efficiencies of PMS by SO(4)(2-) and NO(3)(-) are negligible, whereas remarkable by HCO(3)(-), HPO(4)(2-), Cl(-) and CO(3)(2-). For HCO(3)(-), HPO(4)(2-) and Cl(-), the activation efficiencies become higher with the increase of anion concentration. For CO(3)(2-), however, the activation efficiency is higher at lower concentration.

  18. Ozonation of hydrolyzed azo dye reactive yellow 84 (CI).

    PubMed

    Koch, M; Yediler, A; Lienert, D; Insel, G; Kettrup, A

    2002-01-01

    The combination of chemical and biological water treatment processes is a promising technique to reduce recalcitrant wastewater loads. The key to the efficiency of such a system is a better understanding of the mechanisms involved during the degradation processes. Ozonation has been applied to many fields in water and wastewater treatment. Especially for textile mill effluents ozonation can achieve high color removal, enhance biodegradability, destroy phenols and reduce the chemical oxygen demand (COD). However, little is known about the reaction intermediates and products formed during ozonation. This work deals with the degradation of hydrolyzed Reactive Yellow 84 (Color Index), a widely used azo dye in textile finishing processes with two monochlorotriazine anchor groups. Ozonation of the hydrolyzed dye in ultra pure water was performed in a laboratory scale cylindric batch reactor. Decolorization, determined by measuring the light absorbance at the maximum wavelength in the visible range (400 nm), was almost complete after 60 and 90 min with an ozone concentration of 18.5 and 9.1 mg/l, respectively. The TOC/TOC0 ratio after ozonation was about 30%, the COD was diminished to 50% of the initial value. The BOD5/COD ratio increased from 0.01 to about 0.8. Oxidation and cleavage of the azo group yield nitrate. Cleavage of the sulfonic acid groups of aromatic rings caused increases in the amount of sulfate. Formic acid and oxalic acid were identified as main oxidation products by high performance ion chromatography (HPIC). The concentrations of these major products were monitored at defined time intervals during ozonation.

  19. Photoinduced translational molecular mobility in solid nanostructured azo dye films

    SciTech Connect

    Ezhov, A A; Kozenkov, V M; Magnitskii, Sergey A; Nagorskii, Nikolay M; Panov, Vladimir I

    2011-11-30

    A new mechanism controlling the molecular motion in thin azo-containing films during a photoinduced change in the surface nanorelief is found. It is shown experimentally that exposure of a solid AD-1 azo dye, deposited on a glass substrate, to incoherent linearly polarised light leads to formation of nanostructures with a characteristic size of 200 nm, which are similar to droplets of melt of this dye on the same substrate. It is shown that photoinduced mass transport in a solid AD-1 azo dye film can be explained by the mobility of molecules related to their trans-cis-photoisomerisation, which leads to film softening with subsequent formation of spherical protrusions under surface tension forces.

  20. Chronic toxicity of azo and anthracenedione dyes to embryo-larval fathead minnow.

    PubMed

    Parrott, Joanne L; Bartlett, Adrienne J; Balakrishnan, Vimal K

    2016-03-01

    The toxicity of selected azo and anthracenedione dyes was studied using chronic exposures of embryo-larval fathead minnows (Pimephales promelas). Newly fertilized fathead minnow embryos were exposed through the egg stage, past hatching, through the larval stage (until 14 days post-hatch), with dye solutions renewed daily. The anthracenedione dyes Acid Blue 80 (AB80) and Acid Blue 129 (AB129) caused no effects in larval fish at the highest measured concentrations tested of 7700 and 6700 μg/L, respectively. Both azo dyes Disperse Yellow 7 (DY7) and Sudan Red G (SRG) decreased survival of larval fish, with LC50s (based on measured concentrations of dyes in fish exposure water) of 25.4 μg/L for DY7 and 16.7 μg/L for SRG. Exposure to both azo dyes caused a delayed response, with larval fish succumbing 4-10 days after hatch. If the exposures were ended at the embryo stage or just after hatch, the potency of these two dyes would be greatly underestimated. Concentrations of dyes that we measured entering the Canadian environment were much lower than those that affected larval fish survival in the current tests. In a total of 162 samples of different municipal wastewater effluents from across Canada assessed for these dyes, all were below detection limits. The similarities of the structures and larval fish responses for the two azo and two anthracenedione dyes in this study support the use of read-across data for risk assessment of these classes of compounds.

  1. FATE OF WATER SOLUBLE AZO DYES IN THE ACTIVATED SLUDGE PROCESS

    EPA Science Inventory

    The objective of this study was to determine the partitioning of water soluble azo dyes in the activated sludge process (ASP). Azo dyes are of concern because some of the dyes, dye precursors , and/or their degradation products such as aromatic amines (which are also dye precurso...

  2. Influence of dye type and salinity on aerobic decolorization of azo dyes by microbial consortium and the community dynamics.

    PubMed

    Tan, Liang; Ning, Shuxiang; Wang, Ying; Cao, Xiangyu

    2012-01-01

    In this research, aerobic decolorization of different azo dyes by a microbial community was studied. The results showed that more than 80% of four azo dyes (100 mg/L) could be aerobically decolorized by the microbial consortium, however, the time needed was obviously different. Kinetic data indicated that the processes were well described by zero-order kinetics, and the chemical structures of dyes had obvious influence on decolorization rates. On the other hand, effects of salinity on decolorization were also investigated. There was still 40% dye removal for Acid Brilliant Red GR when the salinity increased to 250 g/L. And the microbial community structures with different salinity were detected by PCR-DGGE. It was shown that the same two bacteria were dominant in all decolorization systems, and some typical halophilic microorganisms were found under higher-salt conditions.

  3. Toxicity assessment and microbial degradation of azo dyes.

    PubMed

    Puvaneswari, N; Muthukrishnan, J; Gunasekaran, P

    2006-08-01

    Toxic effluents containing azo dyes are discharged from various industries and they adversely affect water resources, soil fertility, aquatic organisms and ecosystem integrity. They pose toxicity (lethal effect, genotoxicity, mutagenicity and carcinogenicity) to aquatic organisms (fish, algae, bacteria, etc.) as well as animals. They are not readily degradable under natural conditions and are typically not removed from waste water by conventional waste water treatment systems. Benzidine based dyes have long been recognized as a human urinary bladder carcinogen and tumorigenic in a variety of laboratory animals. Several microorganisms have been found to decolourize, transform and even to completely mineralize azo dyes. A mixed culture of two Pseudomonas strains efficiently degraded mixture of 3-chlorobenzoate (3-CBA) and phenol/cresols. Azoreductases of different microorganisms are useful for the development of biodegradation systems as they catalyze reductive cleavage of azo groups (-N=N-) under mild conditions. In this review, toxic impacts of dyeing factory effluents on plants, fishes, and environment, and plausible bioremediation strategies for removal of azo dyes have been discussed.

  4. Using protein nanofibrils to remove azo dyes from aqueous solution by the coagulation process.

    PubMed

    Morshedi, Dina; Mohammadi, Zeinab; Akbar Boojar, Masoud Mashhadi; Aliakbari, Farhang

    2013-12-01

    The ever-increasing applications of hazardous azo dyes as industrialized coloring agents have led to serious remediation challenges. In this study, proteinaceous nanofibrils were examined as coagulants for decolorization of azo dyes in aqueous solutions. The results provided some insight regarding the mechanism of dye removal. The strength of nanofibrils to remove dyes from solution was evaluated by remediation of acid red 88, Bismarck brown R, direct violet 51, reactive black 5, and Congo red. However, the efficiency of nanofibrils to coagulate with different dyes was variable (60-98%) and dependent on the structures of dyes and the physicochemical conditions of the solutions. Increasing the temperature or ionic strength declined the coagulation time and induced the rate of dye removal. Changing pH had contradictory effects on the dye removal efficiency which was more affected by the chemical structure of the dye rather than the change in stability of the coagulant. The efficiency of nanofibrils to remove dyes was more than that of charcoal, which is considered as one of the most common substances used for azo dye remediation which may be due to its well dispersion in the aqueous solutions, and slower rates of the coagulation than that of the adsorption process. Furthermore, cytotoxicity was not detected after treating cell cultures with the decolorized solutions. Accordingly, by integrating biological and biophysicochemical processes, proteinaceous nanofibrils can be promising candidates for treatment of colored wastewaters. Ease of production, proper and quick dispersion in water, without the production of dangerous dye by-products and derivatives, are some of the main advantages of nanofibrils.

  5. Detoxification of azo dyes in the context of environmental processes.

    PubMed

    Rawat, Deepak; Mishra, Vandana; Sharma, Radhey Shyam

    2016-07-01

    Azo dyes account for >70% of the global industrial demand (∼9 million tons). Owing to their genotoxic/carcinogenic potential, the annual disposal of ∼4,500,000 tons of dyes and/or degraded products is an environmental and socio-economic concern. In comparison to physico-chemical methods, microbe-mediated dye degradation is considered to be low-input, cost-effective and environmentally-safe. However, under different environmental conditions, interactions of chemically diverse dyes with metabolically diverse microbes produce metabolites of varying toxicity. In addition, majority of studies on microbial dye-degradation focus on decolorization with least attention towards detoxification. Therefore, the environmental significance of microbial dye detoxification research of past >3 decades is critically evaluated with reference to dye structure and the possible influence of microbial interactions in different environments. In the absence of ecosystem-based studies, the results of laboratory-based studies on dye degradation, metabolite production and their genotoxic impact on model organisms are used to predict the possible fate and consequences of azo dyes/metabolites in the environment. In such studies, the predominance of fewer numbers of toxicological assays that too at lower levels of biological organization (molecular/cellular/organismic) suggests its limited ecological significance. Based on critical evaluation of these studies the recommendations on inclusion of multilevel approach (assessment at multiple levels of biological organization), multispecies microcosm approach and native species approach in conjunction with identification of dye metabolites have been made for future studies. Such studies will bridge the gap between the fundamental knowledge on dye-microbe-environment interactions and its application to combat dye-induced environmental toxicity. Thus an environmental perspective on dye toxicity in the background of dye structure and effects of

  6. Influence of Methyl Substituents on Azo-Dye Photoalignment in Thin Films

    NASA Astrophysics Data System (ADS)

    Mikulich, V. S.; Murawski, An. A.; Muravsky, Al. A.; Agabekov, V. E.

    2016-03-01

    Photoalignment of azo dyes derived from salicylic acid in thin films (80-200 nm) was studied upon irradiation with polarized light (λmax = 457 nm). It is shown that different trends of molecular reorientation, i.e., in the layer plane or orthogonal to it, are observed depending on the position of the methyl substituent in the dye structure. A new distribution parameter Z that allows the portion of molecules reoriented in the layer plane during exposure to be determined is introduced. The novel azo dye potassium 3,7-bis[1-(4-hydroxy-3-carboxylate)phenylazo]-5,5'-dioxodibenzothiophene was synthesized. Its molecules are photoaligned in the layer plane upon irradiation with polarized light.

  7. Simultaneous chromate reduction and azo dye decolourization by Lactobacillus paracase CL1107 isolated from deep sea sediment.

    PubMed

    Huang, Guangdao; Wang, Wei; Liu, Guoguang

    2015-07-01

    Lactobacillus paracase CL1107 capable of removing toxic chromium (Cr(VI)) and Acid Black (ATT) azo dye simultaneously was isolated from deep sea sediment of the North Atlantic. CL1107 exhibited appreciable dye-Cr(VI) bioremoval ability in the pH range from 5 to 7, temperature 25-35 °C and NaCl 0-6% under aerobic conditions. The maximum removal values of Cr(VI) (95.8%) and dye (92.3%) were obtained in the media including only Cr(VI) or dye at initial concentration of 100 mg/L. In the experiments for the simultaneous treatment of both pollutants, the reduction of Cr(VI) and dye was 58.5% and 51.9%, respectively. The azo dye and Cr(VI) reductive activities in strain CL1107 were located in the cell free extract and cell debris, respectively. The mechanisms of azo dye and Cr(VI) reduction were found to be enzyme-mediated. In the treatment of saline tannery wastewater, decolourization of about 76% and 63% Cr(VI) reduction of were achieved. Furthermore, Azo dyes, Cr(VI) and wastewater showed reduced toxicity toward Artemia salina after treatment. These results demonstrate the potential of CL1107 in bioremediation of dye or/and Cr(VI) contamination in salt environments.

  8. Biodegradation of textile azo dye by Shewanella decolorationis S12 under microaerophilic conditions.

    PubMed

    Xu, Meiying; Guo, Jun; Sun, Guoping

    2007-09-01

    The complete biodegradation of azo dye, Fast Acid Red GR, was observed under microaerophilic conditions by Shewanella decolorationis S12. Although the highest decolorizing rate was measured under anaerobic condition and the highest biomass was obtained under aerobic condition, a further biodegradation of decolorizing products can only be achieved under microaerophilic conditions. Under microaerophilic conditions, S. decolorationis S12 could use a range of carbon sources for azo dye decolorization, including lactate, formate, glucose and sucrose, with lactate being the optimal carbon source. Sulfonated aromatic amines were not detected during the biotransformation of Fast Acid Red GR, while H(2)S formed. The decolorizing products, aniline, 1,4-diaminobenzene and 1-amino-2-naphthol, were followed by complete biodegradation through catechol and 4-aminobenzoic acid based on the analysis results of GC-MS and HPLC.

  9. 40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Naphthalenedisulfonic acid, azo... Significant New Uses for Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, azo]-hydroxy... chemical substance identified generically as naphthalenedisulfonic acid, azo]-hydroxy- , metal salt (PMN...

  10. 40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Naphthalenedisulfonic acid, azo... Significant New Uses for Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, azo]-hydroxy... chemical substance identified generically as naphthalenedisulfonic acid, azo]-hydroxy- , metal salt (PMN...

  11. 40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Naphthalenedisulfonic acid, azo... Significant New Uses for Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, azo]-hydroxy... chemical substance identified generically as naphthalenedisulfonic acid, azo]-hydroxy- , metal salt (PMN...

  12. 40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Naphthalenedisulfonic acid, azo... Significant New Uses for Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, azo]-hydroxy... chemical substance identified generically as naphthalenedisulfonic acid, azo]-hydroxy- , metal salt (PMN...

  13. 40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Naphthalenedisulfonic acid, azo... Significant New Uses for Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, azo]-hydroxy... chemical substance identified generically as naphthalenedisulfonic acid, azo]-hydroxy- , metal salt (PMN...

  14. Non-classical azoreductase secretion in Clostridium perfringens in response to sulfonated azo dye exposure.

    PubMed

    Morrison, Jessica M; John, Gilbert H

    2015-08-01

    Clostridium perfringens, a strictly anaerobic microorganism and inhabitant of the human intestine, has been shown to produce an azoreductase enzyme (AzoC), an NADH-dependent flavin oxidoreductase. This enzyme reduces azo dyes into aromatic amines, which can be carcinogenic. A significant amount of work has been completed on the activity of AzoC. Despite this, much is still unknown, including whether azoreduction of these dyes occurs intracellularly or extracellulary. A physiological study of C. perfringens involving the effect of azo dye exposure was completed to answer this question. Through exposure studies, azo dyes were found to cause cytoplasmic protein release, including AzoC, from C. perfringens in dividing and non-dividing cells. Sulfonation (negative charge) of azo dyes proved to be the key to facilitating protein release of AzoC and was found to be azo-dye-concentration-dependent. Additionally, AzoC was found to localize to the Gram-positive periplasmic region. Using a ΔazoC knockout mutant, the presence of additional azoreductases in C. perfringens was suggested. These results support the notion that the azoreduction of these dyes may occur extracellularly for the commensal C. perfringens in the intestine.

  15. Complete degradation of the azo dye Acid Orange-7 and bioelectricity generation in an integrated microbial fuel cell, aerobic two-stage bioreactor system in continuous flow mode at ambient temperature.

    PubMed

    Fernando, Eustace; Keshavarz, Taj; Kyazze, Godfrey

    2014-03-01

    In this study, the commercially used model azo dye Acid Orange-7 (AO-7) was fully degraded into less toxic intermediates using an integrated microbial fuel cell (MFC) and aerobic bioreactor system. The integrated bioreactor system was operated at ambient temperature and continuous-flow mode. AO-7 loading rate was varied during experiments from 70gm(-3)day(-1) to 210gm(-3)day(-1). Colour and soluble COD removal rates reached>90% under all AO-7 loading rates. The MFC treatment stage prompted AO-7 to undergo reductive degradation into its constituent aromatic amines. HPLC-MS analysis of metabolite extracts from the aerobic stage of the bioreactor system indicated further oxidative degradation of the resulting aromatic amines into simpler compounds. Bioluminescence based Vibrio fischeri ecotoxicity testing demonstrated that aerobic stage effluent exhibited toxicity reductions of approximately fivefold and ten-fold respectively compared to the dye wastewater influent and MFC-stage effluent.

  16. The Comparative Study on the Rapid Decolorization of Azo, Anthraquinone and Triphenylmethane Dyes by Anaerobic Sludge

    PubMed Central

    Cui, Daizong; Zhang, Hao; He, Rubao; Zhao, Min

    2016-01-01

    An anaerobic sludge (AS), capable of decolorizing a variety of synthetic dyes, was acclimated and is reported here. The sludge presented a much better dye decolorizing ability than that of different individual strains. A broad spectrum of dyes could be decolorized by the sludge. Continuous decolorization tests showed that the sludge exhibited the ability to decolorize repeated additions of dye. The chemical oxygen demand (COD) removal rate of the dye wastewater reached 52% after 12 h of incubation. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) profiles revealed that the microbial community changed as a result of varying initial concentrations of dyes. Phylogenetic analysis indicated that microbial populations in the sludge belonged to the phyla Acidobacteria, Firmicutes, Bacteroidetes, Chloroflexi and Proteobacteria. The degradation products of the three types of dye were identified. For azo dyes, the anaerobic sludge converted Methyl Orange to N,N-dimethylbenzene-1,4-diamine and 4-aminobenzenesulfonic acid; for triphenylmethane dyes, after Malachite Green was decolorized, the analyzed products were found to be a mixture of N,N-dimethylbenzenamine, 3-dimethyl-aminophenol and 4-dimethylaminobenzophenone; for anthraquinone dyes, two products (acetophenone and 2-methylbenzoic acid) were observed after Reactive Blue 19 decolorization. Together, these results suggest that the anaerobic sludge has promising potential for use in the treatment of industrial wastewater containing various types of dyes. PMID:27801853

  17. Photodegradation of an azo dye of the textile industry.

    PubMed

    Cisneros, Rosario López; Espinoza, Abel Gutarra; Litter, Marta I

    2002-07-01

    An advanced oxidation treatment, UV/H2O2, was applied to an azo dye, Hispamin Black CA, widely used in the Peruvian textile industry. Rates of color removal and degradation of the dye have been evaluated. A strongly absorbing solution was completely decolorized after 35 min of treatment, and after 60 min an 82% reduction of the total organic carbon (TOC) was obtained. It has been found that the degradation rate increased until an optimum value, beyond which the reagent exerted an inhibitory effect. The degradation rate was also function of pH.

  18. Photocatalytic approach for the reductive decolorization of textile azo dyes in colloidal semiconductor suspensions

    SciTech Connect

    Vinodgopal, K. ); Bedja, I.; Hotchandani, S. ); Kamat, P.V. )

    1994-06-01

    Two representative commercially used textile azo dyes, Acid Orange 7 and Direct Blue 1, have been decolorized using colloidal TiO[sub 2] and WO[sub 3] photocatalytic systems. Under UV irradiation, these dyes undergo rapid decolorization as they are reduced at the semiconductor surface by the trapped electrons. The trapping of electrons in irradiated semiconductor colloids and their participation in the dye reduction process have been probed by steady-state and laser flash photolysis techniques. The quantum efficiency for such a reductive process has been determined to be 4.7%. The rate constant for the electron transfer between the excited semiconductor colloid and the dye is of the order of 10[sup 8] M[sup [minus]1] s[sup [minus]1]. This photocatalytic decolorization approach has potential applications in the treatment of textile dye wastes. 28 refs., 8 figs.

  19. Synthesis and investigation of antimicrobial activity and spectrophotometric and dyeing properties of some novel azo disperse dyes based on naphthalimides.

    PubMed

    Shaki, Hanieh; Gharanjig, Kamaladin; Khosravi, Alireza

    2015-01-01

    A series of novel disperse dyes containing azo group were synthesized through a diazotization and coupling process. The 4-amino-N-2-aminomethylpyridine-1,8-naphthalimide was diazotized by nitrosylsulphuric acid and coupled with various aromatic amines such as N,N-diethylaniline, N,N-dihydroxyethylaniline, 8-hydroxyquinoline, and 2-methylindole. Chemical structures of the synthesized dyes were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), proton nuclear magnetic resonance ((1) H NMR), carbon nuclear magnetic resonance ((13) C NMR), elemental analysis, and ultraviolet-visible (UV-visible) spectroscopy. The spectrophotometric data of all dyes were evaluated in various solvents with different polarity. Eventually, the dyes were applied on polyamide fabrics in order to investigate their dyeing properties. The fastness properties of the dyed fabrics such as wash, light, and rubbing fastness degrees were measured by standard methods. Moreover, the color gamut of the synthesized dyes was measured on polyamide fabrics. Results indicated that some of the synthesized dyes were able to dye polyamide fabrics with deep shades. They had very good wash and rubbing fastness degrees and moderate-to-good light fastness on polyamide fabrics. The antibacterial and antifungal activities of the synthesized dyes were evaluated in soluble state and on the dyed fabrics. The results indicated that dye 2 containing N,N-dihydroxyethylaniline as coupler had the highest activity against all the bacteria and fungi used.

  20. Integration of nanofiltration and biological degradation of textile wastewater containing azo dye.

    PubMed

    Paździor, Katarzyna; Klepacz-Smółka, Anna; Ledakowicz, Stanisław; Sójka-Ledakowicz, Jadwiga; Mrozińska, Zdzisława; Zyłła, Renata

    2009-04-01

    The anaerobic biological azo dyes reduction process was successfully applied to decolourization of the concentrates from the nanofiltration treatment of real textile effluents. The anaerobic phase was followed by aerobic oxidation aimed at the destruction of the aromatic amine released from azo dye. In the first experiment sequential batch reactor (SBR) combining both the anaerobic and aerobic phase in one unit was used. In the second one the anaerobic stage was separated from the aerobic one. The anaerobic phase fulfilled its aim (decolourization) in both systems (over 90%). In opposite, the aromatic amine was completely degraded in the aerobic reactor (two-sludge system), whereas the orthanilic acid was not degraded (during the aerobic phase) in SBR reactor. The COD reduction was also higher in the two-sludge system than in SBR.

  1. Ultrafast degradation of azo dyes catalyzed by cobalt-based metallic glass

    NASA Astrophysics Data System (ADS)

    Qin, X. D.; Zhu, Z. W.; Liu, G.; Fu, H. M.; Zhang, H. W.; Wang, A. M.; Li, H.; Zhang, H. F.

    2015-12-01

    Reactivity and mass loss are considered mutually exclusive in conventional zero-valent metal (ZVM) technology to treat environmental contaminants. Here, we report the outstanding performance of Co-based metallic glass (MG) in degrading an aqueous solution of azo dye, thus eliminating this trade-off. Ball-milled Co-based MG powders completely degrade Acid Orange II at an ultrafast rate. The surface-area-normalized rate constant of Co-based MG powders was one order of magnitude higher than that of Co-based crystalline counterparts and three orders of magnitude higher than that of the widely studied Fe0 powders. The coordinatively unsaturated local structure in Co-based MG responds to the catalysis for degradation, resulting in very low mass loss. Wide applicability and good reusability were also present. Co-based MG is the most efficient material for azo dye degradation reported thus far, and will promote the practical application of MGs as functional materials.

  2. Oxidative degradation of azo dyes using tourmaline.

    PubMed

    Wang, Cuiping; Zhang, Yanwei; Yu, Li; Zhang, Zhiyuan; Sun, Hongwen

    2013-09-15

    This study aimed to investigate the catalyzed degradation ability of tourmaline on the dyes methylene blue (MB), rhodamine B (RhB), and congo red (CR) at different pH values. Interestingly, tourmaline strongly adsorbed anionic dyes, but it did not adsorb cationic dyes. When H₂O₂ was introduced into the tourmaline-dye systems, the degradation percentage for CR catalysis by tourmaline was lower than the percentage of adsorption, whereas the opposite was true for MB and RhB systems. Notably, the catalyzed degradation decreased from 100% to 45% for MB, 100% to 15% for RhB and 100% to 25% for CR as the pH increased from 3.0 to 10.0, respectively, which was much greater than the degradation obtained for previously reported materials at pH values ranging from 4.0 to 10.0. Tourmaline catalytically degraded the dyes over a broad range of pH values, which was attributed to tourmaline automatically adjusting the pH of the dye solutions to approximately 5.5 from an initial range of 4.2-10.0. An electron paramagnetic resonance spin trapping technique observed peroxyl (ROO·) and alkoxy (RO·) or alkyl (R·) radicals originated from the attack of ·OH radicals and O₂(·-) radicals, indicating that these radicals were involved in the catalyzed degradation of MB. Importantly, four intermediate products of MB at m/z 383, 316, 203 and 181 were observed by LC/MS.

  3. Abatement of Azo Dye from Wastewater Using Bimetal-Chitosan

    PubMed Central

    Asgari, Ghorban; Farjadfard, Sima

    2013-01-01

    We introduce a new adsorbent, bimetallic chitosan particle (BCP) that is successfully synthesized and applied to remove the orange II dye from wastewater. The effects of pH, BCP quantity, and contact time are initially verified on the basis of the percentage of orange II removed from the wastewater. Experimental data reveal that the Cu/Mg bimetal and chitosan have a synergistic effect on the adsorption process of the adsorbate, where the dye adsorption by Cu/Mg bimetal, chitosan alone, and bimetal-chitosan is 10, 49, and 99.5%, respectively. The time required for the complete decolorization of orange II by 1 mg/L of BCP is 10 min. The Langmuir model is the best fit for the experimental data, which attains a maximum adsorption capacity of 384.6 mg/g. The consideration of the kinetic behavior indicates that the adsorption of orange II onto the BCP fits best with the pseudo-second-order and Elovich models. Further, the simulated azo dye wastewater can be effectively treated using a relatively low quantity of the adsorbent, 1 mg/L, within a short reaction time of 20 min. Overall, the use of BCP can be considered a promising method for eliminating the azo dye from wastewater effectively. PMID:24348163

  4. Azo Dye Biodecolorization Enhanced by Echinodontium taxodii Cultured with Lignin

    PubMed Central

    Meng, Jing; Yu, Hongbo; Zhang, Xiaoyu

    2014-01-01

    Lignocellulose facilitates the fungal oxidization of recalcitrant organic pollutants through the extracellular ligninolytic enzymes induced by lignin in wood or other plant tissues. However, available information on this phenomenon is insufficient. Free radical chain reactions during lignin metabolism are important in xenobiotic removal. Thus, the effect of lignin on azo dye decolorization in vivo by Echinodontium taxodii was evaluated. In the presence of lignin, optimum decolorization percentages for Remazol Brilliant Violet 5R, Direct Red 5B, Direct Black 38, and Direct Black 22 were 91.75% (control, 65.96%), 76.89% (control, 43.78%), 43.44% (control, 17.02%), and 44.75% (control, 12.16%), respectively, in the submerged cultures. Laccase was the most important enzyme during biodecolorization. Aside from the stimulating of laccase activity, lignin might be degraded by E. taxodii, and then these degraded low-molecular-weight metabolites could act as redox mediators promoting decolorization of azo dyes. The relationship between laccase and lignin degradation was investigated through decolorization tests in vitro with purified enzyme and dozens of aromatics, which can be derivatives of lignin and can function as laccase mediators or inducers. Dyes were decolorized at triple or even higher rates in certain laccase–aromatic systems at chemical concentrations as low as 10 µM. PMID:25285777

  5. The accelerating effect and mechanism of a newly functional bio-carrier modified by redox mediators for the azo dyes decolorization.

    PubMed

    Guo, Jianbo; Kang, Li; Lian, Jing; Yang, Jingliang; Yan, Bin; Li, Zaixing; Liu, Chun; Yue, Lin

    2010-11-01

    In this study, a functional bio-carrier modified by redox meditors was developed as a redox mediator for application in azo dye decolorization processes. Its accelerating effect and mechanism for azo dyes decolorization were also examined. The decolorization rates of 10 azo dyes were enhanced about 1.5-3 fold by the functional bio-carrier modified with disperse turquoise blue S-GL, and the ORP value during the acid red GR decolorization process was changed to a more negative value of 20-25 mV. Non-dissolved redox mediator on the functional bio-carrier played a similar role as NADH during the azo dyes decolorization process. At the same time, the functional bio-carrier exhibited good reusability and the combinational technology of the redox mediator and bio-carrier was a great improvement of the redox mediator application and represents a new bio-treatment concept.

  6. Spectral Studies of UV and Solar Photocatalytic Degradation of AZO Dye and Textile Dye Effluents Using Green Synthesized Silver Nanoparticles

    PubMed Central

    Mariselvam, R.; Ranjitsingh, A. J. A.; Mosae Selvakumar, P.; Alarfaj, Abdullah A.; Munusamy, Murugan A.

    2016-01-01

    The photocatalytic degradation of the chemical dye AZO and dye effluents in different time duration has been investigated using biologically synthesized silver nanoparticles. Dye industry effluents and AZO dye undergo degradation to form harmless intermediate and colourless products following irradiation by UV and solar light in the presence of green synthesized silver nanoparticles. The degree of degradation was tested under the experimental conditions such as PH, temperature, and absorbance of the dye in UV and solar light was measured. The degradation was higher in the UV light source than in the solar light source. Green synthesized silver nanoparticles in the UV light source were found to expedite the dye degradation process. PMID:27382364

  7. Spectral Studies of UV and Solar Photocatalytic Degradation of AZO Dye and Textile Dye Effluents Using Green Synthesized Silver Nanoparticles.

    PubMed

    Mariselvam, R; Ranjitsingh, A J A; Mosae Selvakumar, P; Alarfaj, Abdullah A; Munusamy, Murugan A

    2016-01-01

    The photocatalytic degradation of the chemical dye AZO and dye effluents in different time duration has been investigated using biologically synthesized silver nanoparticles. Dye industry effluents and AZO dye undergo degradation to form harmless intermediate and colourless products following irradiation by UV and solar light in the presence of green synthesized silver nanoparticles. The degree of degradation was tested under the experimental conditions such as P(H), temperature, and absorbance of the dye in UV and solar light was measured. The degradation was higher in the UV light source than in the solar light source. Green synthesized silver nanoparticles in the UV light source were found to expedite the dye degradation process.

  8. Photoluminescence analysis of self induced planer alignment in azo dye dispersed nematic liquid crystal complex

    SciTech Connect

    Kumar, Rishi Sood, Srishti Raina, K. K.

    2014-04-24

    We have developed azo dye doped nematic liquid crystal complex for advanced photonic liquid crystal display technology aspects. Disperse orange azo dye self introduced planer alignment in the nematic liquid crystal without any surface anchoring treatment. Planer alignment was characterized by optical polarizing microscopy. The electro-optical switching response of dye disperse planer aligned nematic cell was investigated as a function of applied voltage with the help of photoluminescence spectrophotometer for the tuning of photoluminescence contrast.

  9. Quinone-mediated decolorization of sulfonated azo dyes by cells and cell extracts from Sphingomonas xenophaga.

    PubMed

    Jiao, Ling; Lu, Hong; Zhou, Jiti; Wang, Jing

    2009-01-01

    The effects of various quinone compounds on the decolorization rates of sulfonated azo dyes by Sphingomonas xenophaga QYY were investigated. The results showed that anthraquinone-2-sulfonate (AQS) was the most effective redox mediator and AQS reduction was the rate-limited step of AQS-mediated decolorization of sulfonated azo dyes. Based on AQS biological toxicity tests, it was assumed that AQS might enter the cells and kill them. In the cytoplasmic extracts from strain QYY, AQS more effectively increased decolorization rates of sulfonated azo dyes than other quinone compounds. In addition, we found a NADH/FMN-dependent AQS reductase using nondenaturing polyacrylamide gel electrophoresis (Native-PAGE).

  10. Relative performance of biofilm configuration over suspended growth operation on azo dye based wastewater treatment in periodic discontinuous batch mode operation.

    PubMed

    Mohan, S Venkata; Reddy, C Nagendranatha; Kumar, A Naresh; Modestra, J Annie

    2013-11-01

    Functional role of biofilm and suspended growth bioreactor configurations in response to the treatment of azo-dye (C.I. Acid Black 10B) bearing wastewater was evaluated in periodic discontinuous batch mode operation at varying dye concentrations. The biofilm system depicted higher dye removal efficiency (93.14%) compared to suspended mode (84.29%) at 350 mg dye/l operation. Both the reactor configurations did not show much process inhibition at higher dye loads studied. Azo reductase and dehydrogenase enzyme activities showed significant variation indicating the different metabolic capabilities of the native-microflora, stable proton shuttling between metabolic intermediates and differences in the delivery of reducing powers from the substrate metabolism towards dye removal. Voltammograms visualized marked variations in electron discharge properties with the function of reactor configuration, time intervals and dye load. Higher redox catalytic currents, lower Tafel slopes and polarization resistance showed good correlation with enzyme activities and dye removal.

  11. Catalytic wet peroxide oxidation of azo dye (Congo red) using modified Y zeolite as catalyst.

    PubMed

    Kondru, Arun Kumar; Kumar, Pradeep; Chand, Shri

    2009-07-15

    The present study explores the degradation of azo dye (Congo red) by catalytic wet peroxide oxidation using Fe exchanged commercial Y zeolite as a catalyst. The effects of various operating parameters like temperature, initial pH, hydrogen peroxide concentration and catalyst loading on the removal of dye, color and COD from an aqueous solution were studied at atmospheric pressure. The percent removals of dye, color and COD at optimum pH(0) 7, 90 degrees C using 0.6 ml H(2)O(2)/350 ml solution and 1g/l catalyst was 97% (in 4h), 100% (in 45 min) and 58% (in 4h), respectively. The % dye removal has been found to be less in comparison to % color removal at all conditions, e.g. dye removal in 45 min and at above conditions was 82%, whereas the color removal was 100%. The results indicate that the Fe exchanged Y zeolite is a promising catalyst for dye removal. Fe exchanged catalyst is characterized using XRD, SEM/EDAX, surface area analyzer and FTIR. Though the dye, color and COD removals were maximum at pH(0) 2 but as the leaching of Fe from the catalyst was more in acidic pH range, pH(0) 7 was taken as operating pH due to almost comparable removals as of pH(0) 2 and no leaching of Fe ions.

  12. Quantification of Adsorption of Azo Dye Molecules on Graphene Oxide Using Optical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chaudhary, Raghvendra Pratap; Pawar, Pranav Bhagwan; Vaibhav, Kumar; Saxena, Sumit; Shukla, Shobha

    2017-02-01

    The presence of azo dye molecules in effluents is a source of water pollution and an environmental hazard. Thus, it is very important to separate out such dye molecules. We have investigated the use of graphene oxide (GO) for the purification of dye-contaminated water. The adsorption efficiency of GO in the degradation of azo dye molecules and the interaction mechanism has been estimated using Ultra Violet-Visible absorption spectroscopy. The charge on the dye molecules along with steric hinderance due to their molecular structure is understood to be detrimental in the adsorption and removal of such dyes. Spectroscopic studies suggest that GO can be used as a potential candidate for efficient removal of cationic azo-dye molecules by adsorption.

  13. Quantification of Adsorption of Azo Dye Molecules on Graphene Oxide Using Optical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chaudhary, Raghvendra Pratap; Pawar, Pranav Bhagwan; Vaibhav, Kumar; Saxena, Sumit; Shukla, Shobha

    2016-11-01

    The presence of azo dye molecules in effluents is a source of water pollution and an environmental hazard. Thus, it is very important to separate out such dye molecules. We have investigated the use of graphene oxide (GO) for the purification of dye-contaminated water. The adsorption efficiency of GO in the degradation of azo dye molecules and the interaction mechanism has been estimated using Ultra Violet-Visible absorption spectroscopy. The charge on the dye molecules along with steric hinderance due to their molecular structure is understood to be detrimental in the adsorption and removal of such dyes. Spectroscopic studies suggest that GO can be used as a potential candidate for efficient removal of cationic azo-dye molecules by adsorption.

  14. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure.

  15. THE MUTAGENICITY OF METALLIZED AND UNMETALLIZED AZO AND FORMAZAN DYES IN THE SALMONELLA MUTAGENICITY ASSAY

    EPA Science Inventory

    The mutagenicity of metallized and unmetallized azo and formazan dyes in the Salmonella mutagenicity
    Laura. C. Edwards', Harold S. Freeman'*, and Larry D. Claxton2

    Abstract
    In previous papers, the synthesis and chemical properties of iron complexed azo and formazan d...

  16. Effect of nitrate on anaerobic azo dye reduction.

    PubMed

    Cirik, Kevser; Kitiş, Mehmet; Çinar, Özer

    2013-01-01

    The aim of the study was to investigate the effect of nitrate on anaerobic color removal efficiencies. For this aim, anaerobic-aerobic sequencing batch reactor (SBR) fed with a simulated textile effluent including Remazol Brilliant Violet 5R azo dye was operated with a total cycle time of 12 h, including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (nitrate) and performance of the system was determined by monitoring color removal efficiency, nitrate removal, nitrite formation and removal, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2 dioxygenase), and formation and removal of aromatic amines. Variations of population dynamics of microorganisms exposed to various amount of nitrate were identified by denaturing gradient gel electrophoresis (DGGE). It was found that nitrate has adverse effect on anaerobic color removal efficiency and color removal was achieved after denitrification process was completed. It was found that nitrate stimulates the COD removal efficiency and accelerates the COD removal in the first hour of anaerobic phase. About 90 % total COD removal efficiencies were achieved in which microorganism exposed to increasing amount of nitrate. Population dynamics of microorganisms exposed to various amount of nitrate were changed and diversity was increased.

  17. Photoinduced Birefringence in Azo-Dye Doped Polyurethane

    NASA Astrophysics Data System (ADS)

    Aleksejeva, J.; Gerbreders, A.; Reinfelde, M.; Teteris, J.

    2011-01-01

    In this report we describe a photoinduced birefringence in disperse red (DR1) azo-dye doped polyurethane films. DR1 dye molecules in these films are chemically bound with the polyurethane polymer's main chain. Under laser radiation the DR1 molecules experience the isomerization process; as a result, the dipole moment of such a molecule changes and they align in the presence of electric field. Photo-birefringence was induced by linearly polarized laser radiation (532 nm, 448 nm, 375 nm and 632.8 nm) in the films with various concentrations of DR1 dye. The photo-induced birefringence (PIBR) Δn was measured at 634 nm wavelength, and its dependences on the pumping beam wavelength and intensity were evaluated. The Δn relaxation was studied both in the dark and under light illumi-nation. In DR1-doped polyurethane films the holographic recording was performed using laser light radiation (532 nm). The profile of surface relief grating (SRG) was studied using AFM. The relationship between SRG formation and PIBR is discussed.

  18. Photoassisted Holography in Azo Dye Doped Polymer Films.

    PubMed

    Rahmouni, Anouar; Bougdid, Yahya; Moujdi, Sara; Nesterenko, Dmitry V; Sekkat, Zouheir

    2016-11-03

    Holographic storage is one of the most important applications in the field of optics, especially for recording and retrieving data, and information storage by interference patterns in photosensitive materials are no exception in this regard. In this work, we give evidence that holograms recorded by interference of two coherent laser beams in azo dye doped polymer films can be controlled by a third incoherent assisting laser beam. We show that light diffraction can be increased or decreased by an assisting beam depending on the respective orientation of the polarizations of the recording and the assisting beams. We also found that photomanipulation of polarization holograms, prepared by polarization modulation, does not depend on the polarization of the assisting beam, whereas, photomanipulation of holograms prepared by intensity modulation strongly depends on the polarization of the assisting beam. Photoselection is shown to play a major role in the photoassisted diffraction process.

  19. Heterogenous solar photocatalysis of two commercial reactive azo dyes.

    PubMed

    Dhodapkar, Rita S; Chaturvedi, Vibha; Neti, Nageswara R; Kaul, Santosh N

    2003-01-01

    Two commercial reactive azo dyes--Reactive Black 5 (RB5) and Reactive Orange 16 (RO 16) have been treated by titanium dioxide and Zinc oxide photocatalysts separately under presence of sunlight. It is observed that solar photocatalytic treatment is effective in terms of colour and COD. The photodegradation efficiency of zinc oxide is comparable with TiO2 at pH 5-6 for RO16. The extent of decolourization and degradation of RB5 is greater in presence of zinc oxide photocatalyst than TiO2 at pH 5- 6. Zinc oxide undergoes <1% photodissolution after 6 hours of solar irradiation at working pH.

  20. Decolorization of azo dyes (Direct Blue 151 and Direct Red 31) by moderately alkaliphilic bacterial consortium.

    PubMed

    Lalnunhlimi, Sylvine; Krishnaswamy, Veenagayathri

    2016-01-01

    Removal of synthetic dyes is one of the main challenges before releasing the wastes discharged by textile industries. Biodegradation of azo dyes by alkaliphilic bacterial consortium is one of the environmental-friendly methods used for the removal of dyes from textile effluents. Hence, this study presents isolation of a bacterial consortium from soil samples of saline environment and its use for the decolorization of azo dyes, Direct Blue 151 (DB 151) and Direct Red 31 (DR 31). The decolorization of azo dyes was studied at various concentrations (100-300mg/L). The bacterial consortium, when subjected to an application of 200mg/L of the dyes, decolorized DB 151 and DR 31 by 97.57% and 95.25% respectively, within 5 days. The growth of the bacterial consortium was optimized with pH, temperature, and carbon and nitrogen sources; and decolorization of azo dyes was analyzed. In this study, the decolorization efficiency of mixed dyes was improved with yeast extract and sucrose, which were used as nitrogen and carbon sources, respectively. Such an alkaliphilic bacterial consortium can be used in the removal of azo dyes from contaminated saline environment.

  1. Decolorization of azo dyes (Direct Blue 151 and Direct Red 31) by moderately alkaliphilic bacterial consortium

    PubMed Central

    Lalnunhlimi, Sylvine; Krishnaswamy, Veenagayathri

    2016-01-01

    Removal of synthetic dyes is one of the main challenges before releasing the wastes discharged by textile industries. Biodegradation of azo dyes by alkaliphilic bacterial consortium is one of the environmental-friendly methods used for the removal of dyes from textile effluents. Hence, this study presents isolation of a bacterial consortium from soil samples of saline environment and its use for the decolorization of azo dyes, Direct Blue 151 (DB 151) and Direct Red 31 (DR 31). The decolorization of azo dyes was studied at various concentrations (100–300 mg/L). The bacterial consortium, when subjected to an application of 200 mg/L of the dyes, decolorized DB 151 and DR 31 by 97.57% and 95.25% respectively, within 5 days. The growth of the bacterial consortium was optimized with pH, temperature, and carbon and nitrogen sources; and decolorization of azo dyes was analyzed. In this study, the decolorization efficiency of mixed dyes was improved with yeast extract and sucrose, which were used as nitrogen and carbon sources, respectively. Such an alkaliphilic bacterial consortium can be used in the removal of azo dyes from contaminated saline environment. PMID:26887225

  2. Differential catalytic action of Brevibacillus laterosporus on two dissimilar azo dyes Remazol red and Rubine GFL.

    PubMed

    Kurade, Mayur B; Waghmode, Tatoba R; Tamboli, Dhawal P; Govindwar, Sanjay P

    2013-02-01

    This comparative study disclosed the diverse catalytic activities of Brevibacillus laterosporus on two different azo dyes. It decolorized 100% of Remazol red and 95% of Rubine GFL within 30 and 48 h respectively, under static condition at 50 mg l⁻¹ dye concentration. Significant increase was observed in azo reductase, NADH-DCIP reductase, veratryl alcohol oxidase and tyrosinase in cells obtained after decolorization of Remazol red; whereas these values were much different with complete inhibition of azo reductase during decolorization of Rubine GFL. The plausible pathway of dye degradation obtained from Gas chromatography-Mass spectroscopy (GC-MS) data confirmed the different metabolic fate of these structurally unidentical dyes. FTIR and HPTLC analysis of extracted metabolites confirmed the biodegradation, while phytotoxicity study assured the detoxification of both the dyes studied. The results obtained in this study suggests, i) sulpho and hydroxyl group present at ortho position to azo group stimulated reduction of azo bond by azo reductase in Remazol red, ii) the same reduction was totally hampered due to presence of ethyl-amino propanenitrile group at para position to azo group in Rubine GFL.

  3. Evaluating role of immobilized periphyton in bioremediation of azo dye amaranth.

    PubMed

    Shabbir, Sadaf; Faheem, Muhammad; Ali, Naeem; Kerr, Philip G; Wu, Yonghong

    2017-02-01

    The aim of this study was to evaluate the bioremediation capabilities of three kinds of periphyton (i.e. epiphyton, metaphyton and epilithon) immobilized in bioreactors to decolorize and biodegrade the sulphonated azo dye, amaranth. Results showed that periphyton dominated by phyla including Cyanobacteria, Proteobacteria and Bacteroidetes. Complete removal of dye was shown by all the biofilms periphyton (epiphyton showed highest removal efficacy) over a range of initial concentrations (50-500mgL(-1)) within 84h at pH 7 and 30°C. Biodegradation of amaranth was confirmed through FTIR and HPLC and the biodegradation pathways were detected by GC-MS/MS analysis. The azo bonds in the amaranth were successfully broken by periphyton and amaranth was converted to non-toxic, aliphatic compounds including isobutene, acetyl acetate and ethyl acetate. The results showed the potential application of immobilized periphyton at industrial scale for the removal of azo dyes from wastewater containing azo dye amaranth.

  4. Integration of photocatalysis and biological treatment for azo dye removal--application to AR183.

    PubMed

    Chebli, Derradji; Fourcade, Florence; Brosillon, Stephan; Nacef, Saci; Amrane, Abdeltif

    2011-04-01

    The feasibility of coupling photocatalysis with biological treatment to treat effluents containing azo dyes was examined in this work. With this aim, the degradation of Acid Red 183 was investigated. The very low biodegradability of AR183 was confirmed beforehand by measuring the biological oxygen demand (BOD5). Photocatalysis experiments were carried out in a closed-loop step photoreactor. The reactor walls were covered by TiO2 catalyst coated on non-woven paper, and the effluent flowed over the photocatalyst as a thin falling film. The removal of the dye was 82.7% after 4 h, and a quasi-complete decolorization (98.5%) was obtained for 10 h of irradiation (initial concentration 100 mg L(-1)). The decrease in concentration followed pseudo-first-order kinetics, with a constant k of 0.47 h(-1). Mineralization and oxidation yields were 80% and 75%, respectively, after 10 h of pretreatment. Therefore, even if target compound oxidation occurs (COD removal), indicating a modification to the chemical structure, the concomitant high mineralization was not in favour of subsequent microbial growth. The BOD5 measurement confirmed the non-biodegradability of the irradiated solution, which remained toxic since the EC50 decreased from 35 to 3 mg L(-1). The proposed integrated process appeared, therefore, to be not relevant for the treatment of AR183. However, this result should be confirmed for other azo dyes.

  5. Developing azo and formazan dyes based on environmental considerations: Salmonella mutagenicity.

    PubMed

    Edwards, Laura C; Freeman, Harold S; Claxton, Larry D

    2004-02-26

    In previous papers, the synthesis and chemical properties of iron-complexed azo and formazan dyes were reported. It was shown that in certain cases iron could be substituted for the traditionally used metals such as chromium and cobalt, without having an adverse effect on dye stability. While these results suggested that the iron analogs were potential replacements for the commercially used chromium and cobalt prototypes, characterization of potentially adverse environmental effects of the new dyes was deemed an essential step in their further development. The present paper provides results from using the Salmonella/mammalian microsome assay to determine the mutagenicity of some important commercial metal complexed dyes, their unmetallized forms, and the corresponding iron-complexed analogs. The study compared the mutagenic properties of six unmetallized azo dyes, six commercial cobalt- or chromium-complexed azo dyes, six iron-complexed azo dyes, six unmetallized formazan dyes, and six iron-complexed formazan dyes. The results of this study suggest that the mutagenicity of the unmetallized dye precursors plays a role in determining the mutagenicity of the iron-complexes. For the monoazo dye containing a nitro group, metal complex formation using iron or chromium decreased or removed mutagenicity in TA100; however, little reduction in mutagenicity was noted in TA98. For the formazan dye containing a nitro group, metal-complex formation using iron increased mutagenicity. Results varied for metal-complexes of azo and formazan dyes without nitro groups, but in general, the metal-complexed dyes based on mutagenic ligands were also mutagenic, while those dyes based on nonmutagenic ligands were nonmutagenic.

  6. Synthesis and evaluation of changes induced by solvent and substituent in electronic absorption spectra of some azo disperse dyes.

    PubMed

    Mohammadi, Asadollah; Yazdanbakhsh, Mohammad Reza; Farahnak, Lahya

    2012-04-01

    Five azo disperse dyes were prepared by diazotizing 4'-aminoacetophenone and p-anisidine and coupling with varies N-alkylated aromatic amines. Characterization of the dyes was carried out by using UV-vis, FTIR and 1H NMR spectroscopic techniques. The electronic absorption spectra of dyes are determined at room temperature in fifteen solvents with different polarities. The solvent dependent maximum absorption band shifts, were investigated using dielectric constant (ɛ), refractive index (n) and Kamlet-Taft polarity parameters (hydrogen bond donating ability (α), hydrogen bond accepting ability (β) and dipolarity/polarizability polarity scale (π*)). Acceptable agreement was found between the maximum absorption band of dyes and solvent polarity parameters especially with π*. The effect of substituents of coupler and/or diazo component on the color of dyes was investigated. The effects of acid and base on the visible absorption maxima of the dyes are also reported.

  7. Investigation of the azo-hydrazone tautomeric equilibrium in an azo dye involving the naphthalene moiety by UV-vis spectroscopy and quantum chemistry

    NASA Astrophysics Data System (ADS)

    Ünal, Arslan; Eren, Bilge; Eren, Erdal

    2013-10-01

    Photophysical properties of the azo-hydrazone tautomerism of Eriochrome Blue Black B (1-(1-hydroxy-2-naphthylazo)-2-naphthol-4-sulphonic acid) in DMF, MeCN and water were investigated using UV-visible spectroscopy and quantum chemical calculations. The optimized molecular structure parameters, relative energies, mole fractions, electronic absorption spectra and HOMO-LUMO energies for possible stable tautomeric forms of EBB were theoretically calculated by using hybrid density functional theory, (B3LYP) methods with 6-31G(d) basis set level and polarizable continuum model (PCM) for solvation effect. The effects of varying pH-, dye concentration-, solvent-, temperature-, and time-dependences on the UV-vis spectra of Eriochrome Blue Black B were also investigated experimentally. The calculations showed that the dye exhibited acid-base, azo-hydrazone and aggregate equilibria in DMF solution, while the most probably preferred form in MeCN solution was azo form. Thermodynamic parameters of dimerization reaction in DMF solution proved that entropy was the driving force of this reaction.

  8. Enzymatic treatment of sulfonated aromatic amines generated from reductive degradation of reactive azo dyes.

    PubMed

    Biswas, Mousumi Mani; Taylor, Keith E; Bewtra, Jatinder K; Biswas, Nihar

    2007-04-01

    Anaerobic degradation, an effective treatment process of textile industry effluent, generates sulfonated aromatic amines, which are carcinogenic, mutagenic, and resistant to microbial degradation. These aromatic amines can be effectively removed by oxidative polymerization catalyzed by peroxidase enzyme. The amines, generated in this study from the anaerobic reduction by zero-valent iron of two reactive azo dyes (Reactive Red 2 [RR2] and Reactive Black 5 [RB5]), were successfully removed (90%) by Arthromyces ramosus peroxidase (ARP). For better understanding of the process, enzymatic treatment of two model compounds, diphenylamine (DPA) and 2-amino-8-naphthol-3,6-disulfonic acid (ANDSA), were also studied. Diphenylamine has a similar diarylamine bond as RR2. The ANDSA has a similar structure as the dye reduction products. The secondary amine bond in DPA and RR2 were oxidized by ARP. Enzymatic reaction of sulfonated aromatic amines generated soluble colored compounds, which were removed by coagulant. Optimum reaction parameters were also determined.

  9. Differential expression of peroxidase and ABC transporter as the key regulatory components for degradation of azo dyes by Penicillium oxalicum SAR-3.

    PubMed

    Saroj, Samta; Kumar, Karunesh; Prasad, Manoj; Singh, R P

    2014-12-01

    Fungal species are potential dye decomposers since these secrete spectra of extracellular enzymes involved in catabolism. However, cellular mechanisms underlying azo dye catalysis and detoxification are incompletely understood and obscure. A potential strain designated as Penicillium oxalicum SAR-3 demonstrated broad-spectrum catabolic ability of different azo dyes. A forward suppression subtractive hybridization (SSH) cDNA library of P. oxalicum SAR-3 constructed in presence and absence of azo dye Acid Red 183 resulted in identification of 183 unique expressed sequence tags (ESTs) which were functionally classified into 12 functional categories. A number of novel genes that affect specifically organic azo dye degradation were discovered. Although the ABC transporters and peroxidases emerged as prominent hot spot for azo dye detoxification, we also identified a number of proteins that are more proximally related to stress-responsive gene expression. Majority of the ESTs (29.5%) were grouped as hypothetical/unknown indicating the presence of putatively novel genes. Analysis of few ESTs through quantitative real-time reverse transcription polymerase chain reaction revealed their possible role in AR183 degradation. The ESTs identified in the SSH library provide a novel insight on the transcripts that are expressed in P. oxalicum strain SAR-3 in response to AR183.

  10. Conducting polypyrrole films as a potential tool for electrochemical treatment of azo dyes in textile wastewaters.

    PubMed

    Haque, Md Mominul; Smith, Warren T; Wong, Danny K Y

    2015-01-01

    In this paper, we demonstrate conducting polypyrrole films as a potential green technology for electrochemical treatment of azo dyes in wastewaters using Acid Red 1 as a model analyte. These films were synthesised by anodically polymerising pyrrole in the presence of Acid Red 1 as a supporting electrolyte. In this way, the anionic Acid Red 1 is electrostatically attracted to the cationic polypyrrole backbone formed to maintain electroneutrality, and is thus entrapped in the film. These Acid Red 1-entrapped polypyrrole films were characterised by electrochemical, microscopic and spectroscopic techniques. Based on a two-level factorial design, the solution pH, Acid Red 1 concentration and polymerisation duration were identified as significant parameters affecting the entrapment efficiency. The entrapment process will potentially aid in decolourising Acid Red 1-containing wastewaters. Similarly, in a cathodic process, electrons are supplied to neutralise the polypyrrole backbone, liberating Acid Red 1 into a solution. In this work, following an entrapment duration of 480 min in 2000 mg L(-1) Acid Red 1, we estimated 21% of the dye was liberated after a reduction period of 240 min. This allows the recovery of Acid Red 1 for recycling purposes. A distinctive advantage of this electrochemical Acid Red 1 treatment, compared to many other techniques, is that no known toxic by-products are generated in the treatment. Therefore, conducting polypyrrole films can potentially be applied as an environmentally friendly treatment method for textile effluents.

  11. Photocatalytic Degradation of Azo Dyes using Doped Titania Fibers

    NASA Astrophysics Data System (ADS)

    Shanmugasundaram, Prasad

    Photo-catalytic degradation using semiconductor particle as dispersion in aqueous medium has been gaining increased attention over the past several years. Their versatility in application makes them unique along with their easy processing techniques and low cost. Titania semiconductor is one of the most important members of this family. It has been widely used for various applications ranging from environmental to bio-medical. Titanium dioxide has gained importance as an effective photo-catalyst because of its advantages over other semiconductor oxides which include high photo-stability, inexpensive, reusable property, chemical and biological inertness, high reactivity, non-toxicity, corrosion resistance, operation at ambient temperatures and its ability to treat trace level pollutants. Its use as a photocatalyst is primarily because of its band gap of 3.0-3.3 eV which can be effectively activated under ultraviolet radiation (wavelength lambda < 400 nm), which leads to electron jump from valence to conduction band. This project aims at developing electrospun titania fibers doped with copper in order to study and demonstrate photocatalytic activity in the visible light spectrum, resulting in quick formation of holes which are ready to react with water to form -OH radicals. A comparative study of pure titania and copper doped titania for degradation of azo dyes were carried out. SEM, EDAX, XRD were carried out to thoroughly understand the structure of the fibers. The photocatalytic activity measurements for different dyes were noted using Uv-Vis method. The fibers when fully developed will be disposable photocatalytic materials for degrading dyes, Organic pollutants and for bio-medical applications when exposed to visible light.

  12. Binding patterns and structure-affinity relationships of food azo dyes with lysozyme: a multitechnique approach.

    PubMed

    Peng, Wei; Ding, Fei; Peng, Yu-Kui; Jiang, Yu-Ting; Zhang, Li

    2013-12-18

    Food dyes serve to beguile consumers: they are often used to imitate the presence of healthful, colorful food produce such as fruits and vegetables. But considering the hurtful impact of these chemicals on the human body, it is time to thoroughly uncover the toxicity of these food dyes at the molecular level. In the present contribution, we have examined the molecular reactions of protein lysozyme with model food azo compound Color Index (C.I.) Acid Red 2 and its analogues C.I. Acid Orange 52, Solvent Yellow 2, and the core structure of azobenzene using a combination of biophysical methods at physiological conditions. Fluorescence, circular dichroism (CD), time-resolved fluorescence, UV-vis absorption as well as computer-aided molecular modeling were used to analyze food dye affinity, binding mode, energy transfer, and the effects of food dye complexation on lysozyme stability and conformation. Fluorescence emission spectra indicate complex formation at 10(-5) M dye concentration, and this corroborates time-resolved fluorescence results showing the diminution in the tryptophan (Trp) fluorescence mainly via a static type (KSV = 1.505 × 10(4) M(-1)) and Förster energy transfer. Structural analysis displayed the participation of several amino acid residues in food dye protein adducts, with hydrogen bonds, π-π and cation-π interactions, but the conformation of lysozyme was unchanged in the process, as derived from fluorescence emission, far-UV CD, and synchronous fluorescence spectra. The overall affinity of food dye is 10(4) M(-1) and there exists only one kind of binding domain in protein for food dye. These data are consistent with hydrophobic probe 8-anilino-1-naphthalenesulfonic acid (ANS) displacement, and molecular modeling manifesting the food dye binding patch was near to Trp-62 and Trp-63 residues of lysozyme. On the basis of the computational analyses, we determine that the type of substituent on the azobenzene structure has a powerful influence on the

  13. Azo dye treatment with simultaneous electricity production in an anaerobic-aerobic sequential reactor and microbial fuel cell coupled system.

    PubMed

    Li, Zhongjian; Zhang, Xingwang; Lin, Jun; Han, Song; Lei, Lecheng

    2010-06-01

    A microbial fuel cell and anaerobic-aerobic sequential reactor coupled system was used for azo dye degradation with simultaneous electricity production. Electricity was produced during the co-metabolism process of glucose and azo dye. A microorganism cultured graphite-granular cathode effectively decreased the charge transfer resistance of the cathode and yielded higher power density. Operation parameters including glucose concentration and hydraulic retention time were optimized. The results indicated that recovering electricity during a sequential aerobic-anaerobic azo dye treatment process enhanced chemical oxygen demand removal and did not decrease azo dye removal. Moreover, UV-vis spectra and GC-MS illustrated that the azo bond was cleaved biologically in the anaerobic chamber and abiotically in the aerobic chamber. The toxic intermediates, aromatic amines, were removed by aerobic treatment. Our work demonstrated that the microbial fuel cell and sequential anode-cathode reactor coupled system could be applied to achieve electricity production with simultaneous azo dye degradation.

  14. Poly(methylmethacrylate) grafted chitosan: An efficient adsorbent for anionic azo dyes.

    PubMed

    Singh, V; Sharma, A K; Tripathi, D N; Sanghi, R

    2009-01-30

    Present study reports on peroxydisulfate/ascorbic acid initiated synthesis of Chitosan-graft-poly(methylmethacrylate) (Ch-g-PMMA) and its characterization by FTIR, XRD and (13)C NMR. The copolymer remained water insoluble even under highly acidic conditions and was evaluated to be an efficient adsorbent for the three anionic azo dyes (Procion Yellow MX, Remazol Brilliant Violet and Reactive Blue H5G) over a wide pH range of 4-10 being most at pH 7. The adsorbent was also found efficient in decolorizing the textile industry wastewater and was much more efficient than the parent chitosan. Equilibrium sorption experiments were carried out at different pH and initial dye concentration values. The experimental equilibrium data for each adsorbent-dye system were successfully fitted to the Langmuir and Freundlich sorption isotherms. Based on Langmuir model Q(max) for yellow, violet and blue dyes was 250, 357 and 178, respectively. Thermodynamic parameters of the adsorption processes such as DeltaG degrees , DeltaH degrees , and DeltaS degrees were calculated. The negative values of free energy reflected the spontaneous nature of adsorption. The adsorption kinetic data of all the three dyes could be well represented by pseudo-second-order model with the correlation coefficients (R(2)) being 0.9922, 0.9997 and 0.9862, for direct yellow, reactive violet and blue dye, respectively with rate constants 0.91 x 10(-4), 1.82 x 10(-4) and 1.05 x 10(-4) g mg(-1)min(-1), respectively. At pH 7, parent chitosan also showed pseudo-second-order kinetics. The temperature dependence of dye uptake and the pseudo-second-order kinetics of the adsorption indicated that chemisorption is the rate-limiting step that controls the process.

  15. Ultrafast degradation of azo dyes catalyzed by cobalt-based metallic glass

    PubMed Central

    Qin, X. D.; Zhu, Z. W.; Liu, G.; Fu, H. M.; Zhang, H. W.; Wang, A. M.; Li, H.; Zhang, H. F.

    2015-01-01

    Reactivity and mass loss are considered mutually exclusive in conventional zero-valent metal (ZVM) technology to treat environmental contaminants. Here, we report the outstanding performance of Co-based metallic glass (MG) in degrading an aqueous solution of azo dye, thus eliminating this trade-off. Ball-milled Co-based MG powders completely degrade Acid Orange II at an ultrafast rate. The surface-area-normalized rate constant of Co-based MG powders was one order of magnitude higher than that of Co-based crystalline counterparts and three orders of magnitude higher than that of the widely studied Fe0 powders. The coordinatively unsaturated local structure in Co-based MG responds to the catalysis for degradation, resulting in very low mass loss. Wide applicability and good reusability were also present. Co-based MG is the most efficient material for azo dye degradation reported thus far, and will promote the practical application of MGs as functional materials. PMID:26656918

  16. A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater.

    PubMed

    Zhang, Yaobin; Jing, Yanwen; Quan, Xie; Liu, Yiwen; Onu, Pascal

    2011-01-01

    Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH(4) content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe(2+) released from ZVI served as a flocculent.

  17. Activated carbon fiber for heterogeneous activation of persulfate: implication for the decolorization of azo dye.

    PubMed

    Chen, Jiabin; Hong, Wei; Huang, Tianyin; Zhang, Liming; Li, Wenwei; Wang, Ying

    2016-09-01

    Activated carbon fiber (ACF) was used as a green catalyst to activate persulfate (PS) for oxidative decolorization of azo dye. ACF demonstrated a higher activity than activated carbon (AC) to activate PS to decolorize Orange G (OG). The decolorization efficiency of OG increased as ACF loading, PS dosage, and temperature increased. OG decolorization followed a pseudo first-order kinetics, and the activation energy was 40.902 kJ/mol. pH had no apparent effect on OG decolorization. Radical quenching experiments with various radical scavengers (e.g., alcohols, phenol) showed that radical-induced decolorization of OG took place on the surface of ACF, and both SO4 (·-) and HO· were responsible for OG decolorization. The impact of inorganic salts was also evaluated because they are important compositions of dye wastewater. Cl(-) and SO4 (2-) exhibited a promoting effect on OG decolorization, and the accelerating rate increased with elevating dosage of ions. Addition of Cl(-) and SO4 (2-) could increase the adsorption of OG on ACF surface, thus favorable for OG decolorization caused by the surface-bound SO4 (·-) and HO·. Conversely, HCO3 (-) and humic acid (HA) slightly inhibited OG decolorization. The azo band and naphthalene ring on OG were remarkably destructed to other intermediates and finally mineralized to CO2 and H2O.

  18. The non-enzymatic reduction of azo dyes by flavin and nicotinamide cofactors under varying conditions.

    PubMed

    Morrison, Jessica M; John, Gilbert H

    2013-10-01

    Azo dyes are ubiquitous in products and often become environmental pollutants due to their anthropogenic nature. Azoreductases are enzymes which are present within many bacteria and are capable of breaking down the azo dyes via reduction of the azo bond. Often, though, carcinogenic aromatic amines are formed as metabolites and are of concern to humans. Azoreductases function via an oxidation-reduction reaction and require cofactors (a nicotinamide cofactor and sometimes a flavin cofactor) to perform their function. Non-enzymatic reduction of azo dyes in the absence of an azoreductase enzyme has been suggested in previous studies, but has never been studied in detail in terms of varying cofactor combinations, different oxygen states or pHs, nor has the enzymatic reduction been compared to azoreduction in terms of dye reduction or metabolites produced, which was the aim of this study. Reduction of azo dyes by different cofactor combinations was found to occur under both aerobic and anaerobic conditions and under physiologically-relevant pHs to produce the same metabolites as an azoreductase. Our results show that, in some cases, the non-enzymatic reduction by the cofactors was found to be equal to that seen with the azoreductase, suggesting that all dye reduction in these cases is due to the cofactors themselves. This study details the importance of the use of a cofactor-only control when studying azoreductase enzymes.

  19. Comparative mutagenicity studies of azo dyes and their reduction products in Salmonella typhimurium

    SciTech Connect

    Krishna, G.; Xu, J.; Nath, J.

    1986-01-01

    The arabinose-resistant and Ames assay systems of Salmonella typhimurium were used to evaluate the mutagenic potential of azo dyes and their aromatic amine reduction products. Azo dyes, namely direct black 38, direct blue 15, and direct red 2, were mutagenic in the arabinose-resistant and Ames assays with both hamster and rat liver S9 activation. Both assays gave relatively higher mutagenic responses with hamster S9. Reduction products of these dyes, namely benzidine, o-dianisidine, and o-tolidine, were mutagenic in the Ames assay. Benzidine was weakly mutagenic and o-dianisidine and o-tolidine were nonmutagenic in the arabinose-resistant assay. These results indicate that both arabinose-resistant tester SV50 and Ames tester TA98 were sensitive in detecting mutagenicity of azo dyes. The use of the standard plate protocol with Ames tester TA98 is more efficient than the modified azo dye protocol in detecting mutagenicity of aromatic amine reduction products. Additional modifications in either the standard plate or modified azo dye protocols may improve detection of mutagenicity of these compounds in the arabinose-resistant assay system.

  20. Decolorization of textile azo dye and Congo red by an isolated strain of the dissimilatory manganese-reducing bacterium Shewanella xiamenensis BC01.

    PubMed

    Ng, I-Son; Chen, Tingting; Lin, Rong; Zhang, Xia; Ni, Chao; Sun, Dongzhe

    2014-03-01

    Shewanella xiamenensis BC01 (SXM) was isolated from sediment collected off Xiamen, China and was identified based on the phylogenetic tree of 16S rRNA sequences and the gyrB gene. This strain showed high activity in the decolorization of textile azo dyes, especially methyl orange, reactive red 198, and recalcitrant dye Congo red, decolorizing at rates of 96.2, 93.0, and 87.5%, respectively. SXM had the best performance for the specific decolorization rate (SDR) of azo dyes compared to Proteus hauseri ZMd44 and Aeromonas hydrophila NIU01 strains and had an SDR similar to Shewanella oneidensis MR-1 in Congo red decolorization. Luria-Bertani medium was the optimal culture medium for SXM, as it reached a density of 4.69 g-DCW L(-1) at 16 h. A mediator (manganese) significantly enhanced the biodegradation and flocculation of Congo red. Further analysis with UV-VIS, Fourier Transform Infrared spectroscopy, and Gas chromatography-mass spectrometry demonstrated that Congo red was cleaved at the azo bond, producing 4,4'-diamino-1,1'-biphenyl and 1,2'-diamino naphthalene 4-sulfonic acid. Finally, SEM results revealed that nanowires exist between the bacteria, indicating that SXM degradation of the azo dyes was coupled with electron transfer through the nanowires. The purpose of this work is to explore the utilization of a novel, dissimilatory manganese-reducing bacterium in the treatment of wastewater containing azo dyes.

  1. Rapid decolorization of azo dyes in aqueous solution by an ultrasound-assisted electrocatalytic oxidation process.

    PubMed

    Ai, Zhihui; Li, Jinpo; Zhang, Lizhi; Lee, Shuncheng

    2010-02-01

    In this study, we developed a novel ultrasound-assisted electrocatalytic oxidation (US-EO) process to decolorize azo dyes in aqueous solution. Rhodamine B was decolorized completely within several minutes in this developed US-EO system. Oxidation parameters such as applied potentials, power of the ultrasound, initial pH of the solution, and initial concentration of RhB were systematically studied and optimized. An obvious synergistic effect was found in decolorization of RhB by the US-EO process when comparing with either ultrasound (US) process or electrocatalytic oxidation (EO) one. Additionally, the decolorization of other azo dyes, such as methylene blue, reactive brilliant red X-3B, and methyl orange, were also effective in the US-EO system. The results indicated that US-EO system was effective for the decolorization of azo dyes, suggesting its great potential in dyeing wastewater treatment.

  2. Kinetic characteristics of bacterial azo-dye decolorization by Pseudomonas luteola.

    PubMed

    Chang, J S; Chou, C; Lin, Y C; Lin, P J; Ho, J Y; Hu, T L

    2001-08-01

    A Pseudomonas luteola strain expressing azoreductase activity was utilized to remove the color of an azo dye (reactive red 22) from contaminated solutions. The effects of substrate concentrations, medium compositions, and operation parameters (e.g., pH, temperature, dissolved oxygen, etc.) on decolorization of the azo dye by a P. luteola strain were systematically investigated to reveal the key factors that dominate the performance of azo-dye decolorization. The metabolites resulting from bacterial decolorization were analyzed by high-performance liquid chromatography (HPLC) and mass spectrometery (MS). The results show that the dissolved oxygen and glucose concentration retarded decolorization of reactive red 22 by P. luteola. The optimal azo-dye decolorization occurred at 37 degrees C, while more rapid decolorization took place over pH 7-9. Yeast extract and tryptone strongly enhanced the decolorization. The Michaelis-Menten model can satisfactorily describe the dependence of specific decolorization rate on the concentration of substrate (reactive red 22 or yeast extract). Decolorization of the azo dye by intact cells of P. luteola was essentially independent of the growth phase, whereas the azoreductase activity of the cell-free extract decreased in the order of late-stationary phase > early-stationary phase > mid-log phase. This suggests that mass transfer of the azo dye across the cell membrane may be the rate-limiting step. The HPLC and MS analyses suggest that both partial reduction and complete cleavage of the azo bond could contribute to decolorization of reactive red 22 by P. luteola.

  3. Crystal structures, solvatochromisms and DFT computations of three disperse azo dyes having the same azobenzene skeleton

    NASA Astrophysics Data System (ADS)

    Qian, Hui-Fen; Tao, Tao; Feng, Ya-Nan; Wang, Yin-Ge; Huang, Wei

    2016-11-01

    Three disperse azo dyes having the same 4-nitrobenzene/azo/4-aminobenzene skeleton but different color have been structurally and spectrally characterized and compared in this paper. X-ray single-crystal diffraction analysis of compound 3 reveals that it has a planar molecular conformation between the azo and the nitrobenzene units. However, severely twisted aminoazobenzene structures in compounds 1 and 2 are observed because of the steric hindrance effect of ortho chloro and bromo groups. Electronic spectra of 1-3 are closely related to their molecular structures, which demonstrate that the presence of different substituted groups and the spatial crowding effect in the aminoazobenzene backbone leads to the significant alterations of bathochromic and hypochromatic shifts. In addition, theoretic computational studies as well as solvatochromisms for three azo dyes have been included.

  4. Electrolysis within anaerobic bioreactors stimulates breakdown of toxic products from azo dye treatment.

    PubMed

    Gavazza, Sávia; Guzman, Juan J L; Angenent, Largus T

    2015-04-01

    Azo dyes are the most widely used coloring agents in the textile industry, but are difficult to treat. When textile effluents are discharged into waterways, azo dyes and their degradation products are known to be environmentally toxic. An electrochemical system consisting of a graphite-plate anode and a stainless-steel mesh cathode was placed into a lab-scale anaerobic bioreactor to evaluate the removal of an azo dye (Direct Black 22) from synthetic textile wastewater. At applied potentials of 2.5 and 3.0 V when water electrolysis occurs, no improvement in azo dye removal efficiency was observed compared to the control reactor (an integrated system with electrodes but without an applied potential). However, applying such electric potentials produces oxygen via electrolysis and promoted the aerobic degradation of aromatic amines, which are toxic, intermediate products of anaerobic azo dye degradation. The removal of these amines indicates a decrease in overall toxicity of the effluent from a single-stage anaerobic bioreactor, which warrants further optimization in anaerobic digestion.

  5. Use of titanium dioxide photocatalysis on the remediation of model textile wastewaters containing azo dyes.

    PubMed

    Saggioro, Enrico Mendes; Oliveira, Anabela Sousa; Pavesi, Thelma; Maia, Cátia Gil; Ferreira, Luis Filipe Vieira; Moreira, Josino Costa

    2011-12-14

    The photocatalytic degradation of two commercial textile azo dyes, namely C.I Reactive Black 5 and C.I Reactive Red 239, has been studied. TiO(2) P25 Degussa was used as catalyst and photodegradation was carried out in aqueous solution under artificial irradiation with a 125 W mercury vapor lamp. The effects of the amount of TiO(2) used, UV-light irradiation time, pH of the solution under treatment, initial concentration of the azo dye and addition of different concentrations of hydrogen peroxide were investigated. The effect of the simultaneous photodegradation of the two azo dyes was also investigated and we observed that the degradation rates achieved in mono and bi-component systems were identical. The repeatability of photocatalytic activity of the photocatalyst was also tested. After five cycles of TiO(2) reuse the rate of colour lost was still 77% of the initial rate. The degradation was followed monitoring the change of azo dye concentration by UV-Vis spectroscopy. Results show that the use of an efficient photocatalyst and the adequate selection of optimal operational parameters may easily lead to a complete decolorization of the aqueous solutions of both azo dyes.

  6. Ozonation of the purified hydrolyzed azo dye Reactive Red 120 (CI).

    PubMed

    Zhang, Feifang; Yediler, Ayfer; Liang, Xinmiao; Kettrup, Antonius

    2002-01-01

    The combination of chemical and biological water treatment processes is a promising technique to reduce recalcitrant wastewater loads. The key to the efficiency of such a system is a better understanding of the mechanisms involved during the degradation processes. Ozonation has been applied to many fields in water and wastewater treatment. Especially for effluents of textile finishing industry ozonation can achieve high color removal, enhance biodegradability, destroy phenols and reduce the COD. However, little is known about the reaction intermediates and products formed during ozonation. This work focuses on the oxidative degradation of purified (>90%), hydrolyzed Reactive Red 120 (Color Index), a widely used azo dye in the textile finishing processes with two monochlorotriazine anchor groups. Ozonation of the dye in ultra pure water was performed in a laboratory scale cylindrical batch reactor. Decolorization, determined by measuring the light absorbance at the maximum wavelength in the visible range (535 nm), was almost complete after 150 min with an ozone concentration of 12.8 mg/l. The TOC/TOC0 ratio was about 74% and the COD was diminished to 46% of the initial value. The BOD5/COD ratio increased from 0.01 to 0.14. To obtain detailed information on the reaction processes during ozonation and the resulting oxidation products organic and inorganic anions were analyzed. Oxidation and cleavage of the azo group yielded nitrate. Cleavage of the sulfonic acid groups of aromatic rings caused an increase in the amount of sulfate. Formic acid and oxalic acid were identified as main oxidation products by high performance ion chromatography (HPIC). The concentrations of these major products were monitored at defined time intervals during ozonation.

  7. Development of an activated carbon-packed microbial bioelectrochemical system for azo dye degradation.

    PubMed

    Cardenas-Robles, Arely; Martinez, Eduardo; Rendon-Alcantar, Idelfonso; Frontana, Carlos; Gonzalez-Gutierrez, Linda

    2013-01-01

    A microbial bioelectrochemical reactor (BER) was employed for the degradation of azo dyes without the use of an external electron donor, using activated carbon (GAC) as a redox mediator. Contribution of pH values, open circuit potential (OCP), dye concentration and applied current were individually studied. A batch system and an upflow fixed bed bioreactor were built for analyzing the effect of the applied current on biodegradation of the azo dye Reactive Red 272. The presence of GAC (20% w/v) regulated both pH and OCP values in solution and led to a removal efficiency of 98%. Cyclic voltammetry results indicate a dependence of the electron transfer mechanism with the concentration of the azo compound. With these results, a continuous flow reactor operating with J=0.045 mA cm(-2), led to removal rates of 95% (± 3.5%) in a half-residence time of 1 hour.

  8. Excellent capability in degrading azo dyes by MgZn-based metallic glass powders.

    PubMed

    Wang, Jun-Qiang; Liu, Yan-Hui; Chen, Ming-Wei; Louzguine-Luzgin, Dmitri V; Inoue, Akihisa; Perepezko, John H

    2012-01-01

    The lack of new functional applications for metallic glasses hampers further development of these fascinating materials. In this letter, we report for the first time that the MgZn-based metallic glass powders have excellent functional ability in degrading azo dyes which are typical organic water pollutants. Their azo dye degradation efficiency is about 1000 times higher than that of commercial crystalline Fe powders, and 20 times higher than the Mg-Zn alloy crystalline counterparts. The high Zn content in the amorphous Mg-based alloy enables a greater corrosion resistance in water and higher reaction efficiency with azo dye compared to crystalline Mg. Even under complex environmental conditions, the MgZn-based metallic glass powders retain high reaction efficiency. Our work opens up a new opportunity for functional applications of metallic glasses.

  9. Decolorization of azo dyes by marine Shewanella strains under saline conditions.

    PubMed

    Liu, Guangfei; Zhou, Jiti; Meng, Xianming; Fu, Shiang Q; Wang, Jing; Jin, Ruofei; Lv, Hong

    2013-05-01

    Azo dye decolorization was studied with Shewanella strains under saline conditions. Growing cells of Shewanella algae and Shewanella marisflavi isolated from marine environments demonstrated better azo dye decolorization capacities than the other three strains from non-saline sources. Cell suspensions of S. algae and S. marisflavi could decolorize single or mixed azo dyes with different structures. Decolorization kinetics were described with Michaelis-Menton equation, which indicated better decolorization performance of S. algae over S. marisflavi. Lactate and formate were identified as efficient electron donors for amaranth decolorization by the two strains. S. algae and S. marisflavi could decolorize amaranth at up to 100 g L(-1) NaCl or Na2SO4. However, extremely low concentration of NaNO3 exerted strong inhibition on decolorization. Both strains could remove the color and COD of textile effluent during sequential anaerobic-aerobic incubation. Lower concentrations of NaCl (20-30 g L(-1)) stimulated the activities of azoreductase, laccase, and NADH-DCIP reductase. The decolorization intermediates were identified by high-performance liquid chromatography and Fourier transform infrared spectroscopy. Decolorization metabolites of amaranth were less toxic than original dye. These findings improved our knowledge of azo-dye-decolorizing Shewanella species and provided efficient candidates for the treatment of dye-polluted saline wastewaters.

  10. Spectrophotometric determination of persulfate by oxidative decolorization of azo dyes for wastewater treatment.

    PubMed

    Ding, Yaobin; Zhu, Lihua; Yan, Jingchun; Xiang, Qingqing; Tang, Heqing

    2011-11-01

    Persulfate can efficiently decolorize azo dyes through oxidizing these compounds, which enabled us to develop a method of rapid spectrophotometric determination of persulfate for monitoring the wastewater treatment on the basis of the oxidation decolorization of azo dyes. Four azo dyes with different molecular structures were investigated as probes, and the influences of operation parameters including reaction time, solution pH, initial dye concentration, and initial concentration of activator Fe(2+) were checked on the determination of persulfate. Under optimum conditions, the decolorization degree of the dyes responded linearly with persulfate concentration for all the four azo dyes, and the linear range and detection limit were found to be 2.0-150 μmol L(-1) and 0.62 μmol L(-1) for rhodamine B, 2.0-100 μmol L(-1) and 0.42 μmol L(-1) for methylene blue, 4.0-150 μmol L(-1) and 0.50 μmol L(-1) for methyl violet, and 20-150 μmol L(-1) and 8.1 μmol L(-1) for orange II. A persulfate treatment of a spiked wastewater sample was satisfactorily monitored with the new method.

  11. Third-order nonlinear optical properties of organic azo dyes by using strength of nonlinearity parameter and Z-scan technique

    NASA Astrophysics Data System (ADS)

    Motiei, H.; Jafari, A.; Naderali, R.

    2017-02-01

    In this paper, two chemically synthesized organic azo dyes, 2-(2,5-Dichloro-phenyazo)-5,5-dimethyl-cyclohexane-1,3-dione (azo dye (i)) and 5,5-Dimethyl-2-tolylazo-cyclohexane-1,3-dione (azo dye (ii)), have been studied from optical Kerr nonlinearity point of view. These materials were characterized by Ultraviolet-visible spectroscopy. Experiments were performed using a continous wave diode-pumped laser at 532 nm wavelength in three intensities of the laser beam. Nonlinear absorption (β), refractive index (n2) and third-order susceptibility (χ (3)) of dyes, were calculated. Nonlinear absorption coefficient of dyes have been calculated from two methods; 1) using theoretical fits and experimental data in the Z-scan technique, 2) using the strength of nonlinearity curves. The values of β obtained from both of the methods were approximately the same. The results demonstrated that azo dye (ii) displays better nonlinearity and has a lower two-photon absorption threshold than azo dye (i). Calculated parameter related to strength of nonlinearity for azo dye (ii) was higher than azo dye (i), It may be due to presence of methyl in azo dye (ii) instead of chlorine in azo dye (i). Furthermore, The measured values of third order susceptibility of azo dyes were from the order of 10-9 esu . These azo dyes can be suitable candidate for optical switching devices.

  12. Spontaneous photoinduced patterning of azo-dye polymer films: the facts

    SciTech Connect

    Hubert, Christophe

    2007-08-15

    We describe the spontaneous photoinduced patterning of azo-dye polymer films. We have observed that the illumination of an azo-dye polymer film by a uniform single laser beam with normal incidence leads to a self-structurization process that results in the formation of well-ordered submicrometer-sized structures whose organization depends on the light polarization direction. A modulation depth as high as 100 nm can be achieved. The influence of several experimental parameters on the structure formation is studied. Results are discussed and confronted to different models and phenomena already investigated in the literature. A physical origin to this peculiar photopatterning process is proposed.

  13. Optical orientation of azo dye molecules in a thin solid film upon nonlinear excitation by femtosecond laser pulses

    SciTech Connect

    Yongseok, Jung; Kozenkov, V M; Magnitskiy, Sergey A; Nagorskiy, Nikolay M

    2006-11-30

    The orientation of molecules in an amorphous pure azo dye film upon nonlinear excitation is detected for the first time. The simultaneous increase and decrease in the film transmission by a factor of 2.5 for orthogonal polarisations of probe radiation indicated the appearance of orientation order in the film caused by the reorientation of azo dye molecules. Due to a high photostability of the AD-1 azo dye demonstrated in single-photon experiments and a high efficiency of nonlinear orientation obtained in experiments with femtosecond pulses, this dye can be widely used in three-dimensional nanophotonic devices such as photonic crystals, optical computers, and optical memory. (letters)

  14. Accelerated decolorization of reactive azo dyes under saline conditions by bacteria isolated from Arabian seawater sediment.

    PubMed

    Khalid, Azeem; Kausar, Farzana; Arshad, Muhammad; Mahmood, Tariq; Ahmed, Iftikhar

    2012-12-01

    Presence of huge amount of salts in the wastewater of textile dyeing industry is one of the major limiting factors in the development of an effective biotreatment system for the removal of azo dyes from textile effluents. Bacterial spp. capable of thriving under high salt conditions could be employed for the treatment of saline dyecontaminated textile wastewaters. The present study was aimed at isolating the most efficient bacterial strains capable of decolorizing azo dyes under high saline conditions. Fiftyeight bacterial strains were isolated from seawater, seawater sediment, and saline soil, using mineral salt medium enriched with 100 mg l−1 Reactive Black-5 azo dye and 50 g NaCl l−1 salt concentration. Bacterial strains KS23 (Psychrobacter alimentarius) and KS26 (Staphylococcus equorum) isolated from seawater sediment were able to decolorize three reactive dyes including Reactive Black 5, Reactive Golden Ovifix, and Reactive Blue BRS very efficiently in liquid medium over a wide range of salt concentration (0-100 g NaCl l)⁻¹. Time required for complete decolorization of 100 mg dye l ⁻¹ varied with the type of dye and salt concentration. In general, there was an inverse linear relationship between the velocity of the decolorization reaction (V) and salt concentration. This study suggested that bacteria isolated from saline conditions such as seawater sediment could be used in designing a bioreactor for the treatment of textile effluent containing high concentration of salts.

  15. Sonoenzymatic decolourization of an azo dye employing immobilized horse radish peroxidase (HRP): a mechanistic study.

    PubMed

    Malani, Ritesh S; Khanna, Swati; Moholkar, Vijayanand S

    2013-07-15

    For degradation of biorefractory pollutants, enzymatic treatments and sonochemical treatments have shown high potential. A combined technique of sono-enzymatic treatment is of special interest as it has shown enhancement effect than the individual techniques. This work has attempted to give a mechanistic insight into the interaction of sonochemical and enzymatic treatments using immobilized horseradish peroxidase (HRP) enzyme on the decolourization of acid red dye (an azo dye). In order to segregate the effect of ultrasound and cavitation, experiments were conducted at elevated static pressure. The kinetic parameters of HRP, viz. Vmax and Km were marginally affected by immobilization. There was a minor change in pH optima and temperature optima for immobilized HRP (6.5, 25°C) from free HRP (7.0, 20-25°C). Though the specific activity of free enzyme (0.272U/mg) was found to be higher than the immobilized enzyme (0.104U/mg), immobilized enzyme exhibited higher stability (up to 3 cycles) and degradation potential than free enzyme in all experiments. The results revealed that the coupling of sonication and enzymatic treatment at high pressure in presence of polyethylene glycol (PEG) yielded the highest decolourization of acid red (61.2%). However, the total decolourization achieved with combined technique was lesser than the sum of individual techniques, indicating negative synergy between the sonochemical and enzymatic techniques.

  16. Parallel Combinatorial Synthesis of Azo Dyes: A Combinatorial Experiment Suitable for Undergraduate Laboratories

    ERIC Educational Resources Information Center

    Gung, Benjamin W.; Taylor, Richard T.

    2004-01-01

    An experiment in the parallel synthesis of azo dyes that demonstrates the concepts of structure-activity relationships and chemical diversity with vivid colors is described. It is seen that this experiment is suitable for the second-semester organic chemistry laboratory and also for the one-semester organic laboratory.

  17. Development of a novel high-entropy alloy with eminent efficiency of degrading azo dye solutions

    NASA Astrophysics Data System (ADS)

    Lv, Z. Y.; Liu, X. J.; Jia, B.; Wang, H.; Wu, Y.; Lu, Z. P.

    2016-09-01

    In addition to its scientific importance, the degradation of azo dyes is of practical significance from the perspective of environmental protection. Although encouraging progress has been made on developing degradation approaches and materials, it is still challenging to fully resolve this long-standing problem. Herein, we report that high entropy alloys, which have been emerging as a new class of metallic materials in the last decade, have excellent performance in degradation of azo dyes. In particular, the newly developed AlCoCrTiZn high-entropy alloy synthesized by mechanical alloying exhibits a prominent efficiency in degradation of the azo dye (Direct Blue 6: DB6), as high as that of the best metallic glass reported so far. The newly developed AlCoCrTiZn HEA powder has low activation energy barrier, i.e., 30 kJ/mol, for the degrading reaction and thus make the occurrence of reaction easier as compared with other materials such as the glassy Fe-based powders. The excellent capability of our high-entropy alloys in degrading azo dye is attributed to their unique atomic structure with severe lattice distortion, chemical composition effect, residual stress and high specific surface area. Our findings have important implications in developing novel high-entropy alloys for functional applications as catalyst materials.

  18. Development of a novel high-entropy alloy with eminent efficiency of degrading azo dye solutions.

    PubMed

    Lv, Z Y; Liu, X J; Jia, B; Wang, H; Wu, Y; Lu, Z P

    2016-09-28

    In addition to its scientific importance, the degradation of azo dyes is of practical significance from the perspective of environmental protection. Although encouraging progress has been made on developing degradation approaches and materials, it is still challenging to fully resolve this long-standing problem. Herein, we report that high entropy alloys, which have been emerging as a new class of metallic materials in the last decade, have excellent performance in degradation of azo dyes. In particular, the newly developed AlCoCrTiZn high-entropy alloy synthesized by mechanical alloying exhibits a prominent efficiency in degradation of the azo dye (Direct Blue 6: DB6), as high as that of the best metallic glass reported so far. The newly developed AlCoCrTiZn HEA powder has low activation energy barrier, i.e., 30 kJ/mol, for the degrading reaction and thus make the occurrence of reaction easier as compared with other materials such as the glassy Fe-based powders. The excellent capability of our high-entropy alloys in degrading azo dye is attributed to their unique atomic structure with severe lattice distortion, chemical composition effect, residual stress and high specific surface area. Our findings have important implications in developing novel high-entropy alloys for functional applications as catalyst materials.

  19. Transient gratings in thin films and bulk azo-dye-containing poly(methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    Luo, Duanbin; Lu, Wei; Wu, Shuizhu

    2005-02-01

    Using holographic recording technology, two kinds of transient diffraction gratings were demonstrated in azo-dye doped Poly(methyl methacrylate) (PMMA) films and bulk matrices respectively. In PMMA films containing azo-dye Disperse Red 13 (DR13), the refractive index gratings came from the reorientation of azo-dye molecules in different areas with different polarization distribution of recording beams. The characteristics of the transient gratings in films samples which were recorded by two mutually parallel polarization beams (PP and SS) as well as orthogonal linear polarization beams (PS and +/-45°) from an Ar ion laser (514nm) were investigated by monitoring the first order diffraction intensity of the readout He-Ne laser beam (632.8nm). With the interaction of bi-photonic lights at 514nm and 632.8nm, the transient gratings in azo-dye DR13 doped PMMA bulk matrices was a kind of population gratings of Trans and Cis isomers, which was attributed to the weak absorption of Cis isomers at 632.8nm and the positive dichroism of Trans isomers at 514nm. Furthermore, the all-optical switching behavior of the two kinds of transient holographic gratings were observed repeatedly by turning on and off the writing beams, and a response time at the magnitude of ten milliseconds order could be obtained.

  20. Development of a novel high-entropy alloy with eminent efficiency of degrading azo dye solutions

    PubMed Central

    Lv, Z. Y.; Liu, X. J.; Jia, B.; Wang, H.; Wu, Y.; Lu, Z. P.

    2016-01-01

    In addition to its scientific importance, the degradation of azo dyes is of practical significance from the perspective of environmental protection. Although encouraging progress has been made on developing degradation approaches and materials, it is still challenging to fully resolve this long-standing problem. Herein, we report that high entropy alloys, which have been emerging as a new class of metallic materials in the last decade, have excellent performance in degradation of azo dyes. In particular, the newly developed AlCoCrTiZn high-entropy alloy synthesized by mechanical alloying exhibits a prominent efficiency in degradation of the azo dye (Direct Blue 6: DB6), as high as that of the best metallic glass reported so far. The newly developed AlCoCrTiZn HEA powder has low activation energy barrier, i.e., 30 kJ/mol, for the degrading reaction and thus make the occurrence of reaction easier as compared with other materials such as the glassy Fe-based powders. The excellent capability of our high-entropy alloys in degrading azo dye is attributed to their unique atomic structure with severe lattice distortion, chemical composition effect, residual stress and high specific surface area. Our findings have important implications in developing novel high-entropy alloys for functional applications as catalyst materials. PMID:27677462

  1. DEVELOPING AZO AND FORMAZAN DYES BASED ON ENVIRONMENTAL CONSIDERATIONS: SALMONELLA MUTAGENICITY

    EPA Science Inventory

    Abstract
    In previous papers, the synthesis and chemical properties of iron-complexed azo and formazan dyes were reported. In this regard, it was shown that in certain cases iron could be substituted for the traditionally used metals, chromium and cobalt, without having an adve...

  2. Isolation and characterization of a Klebsiella oxytoca strain for simultaneous azo-dye anaerobic reduction and bio-hydrogen production.

    PubMed

    Yu, Lei; Li, Wen-Wei; Lam, Michael Hon-Wah; Yu, Han-Qing; Wu, Chao

    2012-07-01

    A facultative anaerobic bacteria strain GS-4-08, isolated from an anaerobic sequence batch reactor for synthetic dye wastewater treatment, was investigated for azo-dye decolorization. This bacterium was identified as a member of Klebsiella oxytoca based on Gram staining, morphology characterization and 16S rRNA gene analysis. It exhibited a good capacity of simultaneous decolorization and hydrogen production in the presence of electron donor. The hydrogen production was less affected even at a high Methyl Orange (MO) concentration of 0.5 mM, indicating a superior tolerability of this strain to MO. This efficient bio-hydrogen production from electron donor can not only avoid bacterial inhibition due to accumulation of volatile fatty acids during MO decolorization, but also can recover considerable energy from dye wastewater.

  3. Study of bio-degradation and bio-decolourization of azo dye by Enterobacter sp. SXCR.

    PubMed

    Prasad, Shiv Shankar; Aikat, Kaustav

    2014-01-01

    The objective of this study was to evaluate the decolourization potential of textile dyes by a relatively newly identified bacteria species, Enterobacter sp. SXCR which was isolated from the petroleum polluted soil samples. The bacterial strain was identified by 16S rRNA gene sequence analysis. The effects of operational conditions like initial dye concentration, pH, and temperature were optimized to develop an economically feasible decolourization process. The isolate was able to decolourize sulphonated azo dye (Congo red) over a wide range (0.1-1 gl(-1)), pH 5-9, and temperature 22-40 degrees C in static condition. Anaerobic condition with minimal salt medium supplemented with 2 gl(-1) glucose, pH 7 and 34 degrees C were considered to be the optimum decolourizing condition. The bacterial isolate SXCR showed a strong ability to decolourize dye (0.2 gl(-1)) within 93 h. The biodegradation was monitored by UV-vis, fourier transform infra-red spectroscopy (FTIR) spectroscopy and high performance liquid chromatography (HPLC). Furthermore, the involvement of azoreductase in the decolourization process was identified in this strain. Cells of Enterobacter cloacae were immobilized by entrapment in calcium-alginate beads. Immobilized bacterial cells were able to reduced azo bonds enzymatically and used as a biocatalyst for decolourization of azo dye Congo red. Michaelis-Menten kinetics was used to describe the correlation between the decolourization rate and the dye concentration.

  4. All-optical switchable holographic Fresnel lens based on azo-dye-doped polymer-dispersed liquid crystals.

    PubMed

    Jashnsaz, Hossein; Nataj, Nahid Hosain; Mohajerani, Ezeddin; Khabbazi, Amir

    2011-08-01

    Fabrication of an all-optical switchable holographic liquid crystal (LC) Fresnel lens based on azo-dye-doped polymer-dispersed LCs is reported using a Michelson interferometer. It is found that, upon circularly polarized photoirradiation, the diffraction efficiency of the fabricated Fresnel lens was increased significantly in a reversible manner. We believe this is due to the anisotropy induced by reorientation of the LC molecules coupled with azo-dye molecule orientation due to trans-cis-trans photoisomerization, which modulates the refractive index of the LC-rich regions. We also studied the effect of azo dye on the polarization dependency of the fabricated lens.

  5. Enhanced azo dye removal through anode biofilm acclimation to toxicity in single-chamber biocatalyzed electrolysis system.

    PubMed

    Wang, You-Zhao; Wang, Ai-Jie; Liu, Wen-Zong; Sun, Qian

    2013-08-01

    Azo dye is widely used in printing and dyeing process as one of refractory wastewaters for its high chroma, stable chemical property and toxicity for aquatic organism. Biocatalyzed electrolysis system (BES) is a new developed technology to degrade organic waste in bioanode and recover recalcitrant contaminants in cathode with effective decoloration. The ion exchange membrane (IEM) separate anode and cathode for biofilm formation protection. Azo removal efficiency was up to 60.8%, but decreased to 20.5% when IEM was removed. However, expensive ion exchange membrane (IEM) not suitable for further practical application, bioelectrochemical activity of bioanode is sensitive to the toxicity of azo dye. A gradient increase of azo dye concentration was used to acclimate anode biofilm to pollutant toxicity. The azo removal efficiency can be enhanced to 73.3% in 10h reaction period after acclimation. The highest removal efficiency reached 83.7% and removal rates were increased to 8.37 from 3.04 g/h/L of dual-chamber. That indicated the feasibility for azo dye removal by single-chamber BES. The IEM cancellation not only decreased the internal resistance, but increased the current density and azo dye removal.

  6. New 1,2,4-triazole-based azo-azomethine dyes. Part I: Synthesis, characterization and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Hamid; Erfantalab, Malihe

    2012-02-01

    Four new 1,2,4-triazole-based azo-azomethine dyes were synthesized via condensation of 3,5-diamino-1,2,4-triazole with azo-coupled o-vanillin precursors. The prepared dyes were characterized by IR, UV-vis and 1H NMR spectroscopic methods as well as elemental analyses. Thermal properties of the prepared dyes were examined by thermogravimetric analysis. Results indicated that the framework of the dyes was stable up to 225 °C. Also, the influence of various factors including time and mixed DMSO/EtOH solution on UV-vis spectra of the dyes were investigated.

  7. Effect of Fenton's treatment on the biodegradability of chromium-complex azo dyes.

    PubMed

    Arslan-Alaton, I; Kabdaşli, I; Teksoy, S

    2007-01-01

    Pretreatment of an acid dyebath effluent bearing a new generation chromium complex azo dyestuff (C0 = 350 mg/L) with Fenton's reagent was investigated. Preliminary optimisation (baseline) experiments were conducted to determine the Fe2+, H2O2 concentrations and pH required to the highest possible COD and colour removals. Kinetic studies were carried out at varying temperatures (20 degrees C < T < 70 degrees C) to establish a relationship between COD abatement and H2O2 consumption. The activation energy found for catalytic H2O2 decomposition (Ea = 9.8 kJ/mol) appeared to be significantly less than that of fermentative (Ea = 23 kJ/mol) and of thermal (Ea = 76 kJ/mol) H2O2 decomposition, implying that H2O2 decomposition during the Fenton's reaction occurs more spontaneously. The experimental studies indicated that approximately 30% COD and complete colour removal could be achieved under optimised Fenton pretreatment conditions (Fe2+ = 2 mM; H2O2 = 30 mM; pH = 3; at T = 60 degrees C). Long-term activated sludge experiments revealed that although the raw and pretreated acid dyebath effluent contained practically the same amount of "readily biodegradable" COD (inert COD fraction < or = 10%), biodegradation of the chemically pretreated acid dye effluent proceeded appreciably faster than that of the untreated acid dyebath effluent.

  8. Analysis of anionic metallized azo and formazan dyes by capillary electrophoresis-mass spectrometry.

    PubMed

    Poiger, T; Richardson, S D; Baughman, G L

    2000-07-21

    Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cm x 50 microm uncoated fused-silica capillary and a 5 mM ammonium acetate buffer (pH 9) containing 40% acetonitrile. Excellent separation efficiencies (N = 500,000 plates/column) and low detection limits of 20-50 pg (selected ion monitoring, S/N = 10) were achieved. Mass spectra were acquired at different cone voltages. At low cone voltages (low collision energies), sensitivity was maximized and the mass spectra contained only signals of the (multiply charged) molecular ions and low levels of sodium ion and proton adducts. At higher cone voltages, the 2:1 (ligand:metal) chromium and cobalt dyes showed losses of one of the two dye ligands, accompanied by a reduction of the metal. The copper dyes showed signals due to loss of SO2 and SO3-, but no release of metal. Azo cleavage, otherwise typical of azo dyes, was not observed with the metallized dyes.

  9. Retardation of the orientation relaxation of azo-dye doped amorphous polymers upon photoinduced isomerization

    NASA Astrophysics Data System (ADS)

    Chan, S. W.; Quatela, A.; Casalboni, M.; Nunzi, J.-M.

    2006-08-01

    The orientation relaxation upon photo-induced isomerization of azo-dyes was studied. All-optical poling (AOP) and photo-induced birefringence, which are based on the mechanism of angular selective photo-isomerization, were employed to manipulate the angular distribution of azo-dyes (Disperse-red 1) doped in three different amorphous polymers: (poly(methyl methacrylate) PMMA, poly(carbonate) PC and poly(sulfone) PSU), with different glass transition temperature (T g). In the case of AOP, quasi-permanent macroscopic second-order nonlinear optical susceptibility χ (2) was inscribed in the dye-doped centro-symmetric polymer systems, while in the case of photo-induced birefringence, quasi-permanent birefringence Δn was inscribed in the dye-doped isotropic polymer systems. Relaxation of χ (2) and Δn were monitored upon different duration of AOP and photo-induced birefringence preparation. Experimental results show that azo-dye orientation relaxation follows the duration of the photo-nduced isomerization process: the longer the photo-induced isomerization process, the slower the relaxation of the inscribed χ (2) and Δn. In addition, retardation of the orientation relaxation does not follow a simple relation with hardness (T g) of the polymer host. Causes of the orientation relaxation retardation are discussed.

  10. Synthesis and anion recognition studies of novel bis (4-hydroxycoumarin) methane azo dyes

    NASA Astrophysics Data System (ADS)

    Panitsiri, Amorn; Tongkhan, Sukanya; Radchatawedchakoon, Widchaya; Sakee, Uthai

    2016-03-01

    Four new bis (4-hydroxycoumarin) methane azo dyes were synthesized by the condensation of 4-hydroxycoumarin with four different azo salicylaldehydes and their structures were characterized by FT-IR, 1H NMR, 13C NMR, HRMS. Anion binding ability in dimethyl sulfoxide (DMSO) solutions with tetrabutylammonium (TBA) salts (F-, Cl-, Br-, I-, AcO- and H2PO4-) was investigated by the naked eye, as well as UV-visible spectroscopy. The sensor shows selective recognition towards fluoride and acetate. The binding affinity of the sensors with fluoride and acetate was calculated using UV-visible spectroscopic technique.

  11. Stretched exponential kinetics for photoinduced birefringence in azo dye doped PVA films

    NASA Astrophysics Data System (ADS)

    Yang, Hye Ri; Kim, Eun Ju; Lee, Sang Jo; Kim, Gun Yeup; Kwak, Chong Hoon

    2009-05-01

    We fabricated azo dye (methylorange) doped poly vinyl alcohol (MO/PVA) thin films and measured the photoinduced birefringence (PIB) kinetics for several pump beam intensities and for various MO concentrations by using the pump-probe technique. A novel approach to explain the transient behaviors of the photoinduced anisotropy is presented by employing an empirical stretched exponential time response in the course of the trans-cis-trans photoisomerization of azo molecules and is compared with the experimental data, showing excellent agreement. The stretched exponent is estimated to be β = 0.34 ± 0.04, revealing amorphous nature of the MO/PVA system.

  12. Photoreversible optical data recording in films of amorphous azo dye-containing polymers

    SciTech Connect

    Simonov, A N; Uraev, D V; Shibaev, Valerii P; Kostromin, S G

    2002-02-28

    The photoreversible properties of films of amorphous azo-containing polymers (AAPs) are studied theoretically and experimentally. The control of the sign of a photoinduced addition {Delta}n{sup ind} to the refractive index of the polymer by changing polarisation of the incident light is demonstrated. A theoretical model of photoinduced processes in AAP films is proposed, which takes into account the orientation diffusion of trans-isomers of azo dyes, and simplified analytic approaches describing the photoorientation dynamics in AAPs are considered. The theoretical results are in good agreement with our experimental data. (laser applications and other topics in quantum electronics)

  13. Spectroscopic and theoretical study of the "azo"-dye E124 in condensate phase: evidence of a dominant hydrazo form.

    PubMed

    Almeida, Mariana R; Stephani, Rodrigo; Dos Santos, Hélio F; de Oliveira, Luiz Fernando C

    2010-01-14

    Spectroscopic techniques, including Raman, IR, UV/vis, and NMR were used to characterize the samples of the azo dye Ponceau 4R (also known as E124, New Coccine; Cochineal Red; C.I. no. 16255; Food Red No. 102), which is 1,3-naphthalenedisulfonic acid, 7-hydroxy-8-[(4-sulfo-1-naphthalenyl) azo] trisodium salt in aqueous solution and solid state. In addition, first principle calculations were carried out for the azo (OH) and hydrazo (NH) tautomers in order to assist in the assignment of the experimental data. The two intense bands observed in the UV/vis spectrum, centered at 332 and 507 nm, can be compared to the calculated values at 296 and 474 nm for azo and 315 and 500 nm for hydrazo isomer, with the latter in closer agreement to the experiment. The Raman spectrum is quite sensitive to tautomeric equilibrium; in solid state and aqueous solution, three bands were observed around 1574, 1515, and 1364 cm(-1), assigned to mixed modes including deltaNH + betaCH + nuCC, deltaNH + nuC horizontal lineO + nuC horizontal lineN + betaCH and nuCC vibrations, respectively. These assignments are predicted only for the NH species centered at 1606, 1554, and 1375 cm(-1). The calculated Raman spectrum for the azo (OH) tautomer showed two strong bands at 1468 (nuN = N + deltaOH) and 1324 cm(-1) (nuCC + nuC-N), which were not obtained experimentally. The (13)C NMR spectrum showed a very characteristic peak at 192 ppm assigned to the carbon bound to oxygen in the naphthol ring; the predicted values were 165 ppm for OH and 187 for NH isomer, supporting once again the predominance of NH species in solution. Therefore, all of the experimental and theoretical results strongly suggest the food dye Ponceau 4R or E124 has a major contribution of the hydrazo structure instead of the azo form as the most abundant in condensate phase.

  14. Degradation of azo dye direct sky blue 5B by sonication combined with zero-valent iron.

    PubMed

    Chen, Bing; Wang, Xikui; Wang, Chen; Jiang, Wenqiang; Li, Shuping

    2011-09-01

    The degradation of azo dye direct sky blue 5B by sonication combined with zero-valent iron (US-Fe(0))was investigated and an evident synergistic effect was observed. The synergetic effect is mainly due to the increase of ()OH radical concentration from Fenton's reaction. The ()OH radical concentrations in sole sonication and US-Fe(0) process were detected by using terephthalic acid as a fluorescent probe and found that ()OH radicals were generated continuously during sonication and the production of ()OH radicals in US-Fe(0) process was much higher than that in sole sonication. The degradation of direct sky blue 5B followed a pseudo-first-order kinetics and the degradation rate constants were found to be 0.0206 and 0.169 min(-1) with sole sonication and US-Fe(0) process respectively. It was also found that the degradation ratio of direct sky blue 5B increased with the increase of zero-valent iron dosage and decrease of pH value of the dye aqueous solution. The degradation mechanism of direct sky blue 5B with US-Fe(0) process was discussed by the changes of UV-Vis spectrogram of the dye during degradation. The dramatic changes of UV spectra showed a disappearance of both azo and aromatic groups during the degradation.

  15. Effects of redox mediators on azo dye decolorization by Shewanella algae under saline conditions.

    PubMed

    Meng, Xianming; Liu, Guangfei; Zhou, Jiti; Fu, Q Shiang

    2014-01-01

    Azo dye decolorization by Shewanella algae (SAL) in the presence of high concentrations of NaCl and different quinones or humic acids was investigated to reveal the effects of redox mediator under saline conditions. Growth of SAL and the other two marine Shewanella strains coupled to anthraquinone-2,6-disulfonate (AQDS) reduction was observed in a wide range of NaCl concentrations (0-7%). AQDS showed the best enhancing effects, whereas some other quinones demonstrated poorer stimulating or even inhibiting effects on acid red 27 (AR27) decolorization. Different humic acids could also enhance the decolorization. The correlation between specific AQDS-mediated reduction rate and initial AR27 concentration could be described with Michaelis-Menten kinetics (Km=0.2 mM and Vmax=9.3 μmol mg cell(-1) h(-1)). AQDS reduction by SAL was determined to be the rate-limiting step of mediated reduction. Mediated decolorization products of AR27 were determined to be less phytotoxic aromatic amines.

  16. Energy-efficient photodegradation of azo dyes with TiO(2) nanoparticles based on photoisomerization and alternate UV-visible light.

    PubMed

    Zhang, Hao; Chen, Da; Lv, Xiaojun; Wang, Ying; Chang, Haixin; Li, Jinghong

    2010-02-01

    Herein, we demonstrated a UV-vis light alternate photocatalysis (UVLAP) strategy in the photodegradation of azo dyes. The UVLAP of azo dyes over TiO(2) catalysts exhibited significantly higher energy efficiency than the conventional UV process by 40%, which was attributed to the photoisomerization of azo dyes and the resulting diversity of dyes' cis and trans states in interfacial properties, including conductance and spatial effects. This UVLAP strategy could contribute to the energy-saving photodegradation of azo dyes and other pollutants with photoisomerization properties and facilitate the practical application of TiO(2) in the environmental remediation.

  17. Enhanced rates of photocatalytic degradation of an azo dye using SnO{sub 2}/TiO{sub 2} coupled semiconductor thin films

    SciTech Connect

    Vinodgopal, K.; Kamat, P.V.

    1995-03-01

    We present here for the first time the results from electrochemically assisted photocatalytic experiments using coupled TiO{sub 2}/SnO{sub 2} semiconductor thin films in the degradation of textile dye effluent. We show that by using such a system the oxidative efficiency of photocatalytic semiconductor systems in degrading a commercial azo dye such as Acid Orange 7 (AO7) can be improved. The results presented here on the decolorization of the azo dye AO7 represents a major step forward in the development of new advanced oxidation processes for the treatment of such industrial waste. The improved charge separation as a result of coupling two semiconductor systems with different energy levels and the applied anodic bias is responsible for the enhancement in the rate of photocatalytic degradation. 20 refs., 6 figs.

  18. Fastest non-ionic azo dyes and transfer of their thermal isomerisation kinetics into liquid-crystalline materials.

    PubMed

    Garcia-Amorós, Jaume; Castro, M Cidália R; Coelho, Paulo; Raposo, M Manuela M; Velasco, Dolores

    2016-04-14

    Push-pull bithienylpyrrole-based azo dyes exhibit thermal isomerisation rates as fast as 1.4 μs in acetonitrile at 298 K becoming, thus, the fastest neutral azo dyes reported so far. These remarkably low relaxation times can be transferred into liquid-crystalline matrices enabling light-triggered oscillations in the optical density of the final material up to 11 kHz under ambient conditions.

  19. Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes

    PubMed Central

    Lade, Harshad; Kadam, Avinash; Paul, Diby; Govindwar, Sanjay

    2015-01-01

    Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L-1 concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn’t show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic

  20. Photoinduced grating formation in a polymer containing azo-carbazole dyes.

    PubMed

    Kawabe, Yutaka; Fukuzawa, Kodai; Uemura, Takuya; Matsuura, Katsufumi; Yoshikawa, Toshio; Nishide, Jun-ichi; Sasabe, Hiroyuki

    2012-09-20

    Although some azo-carbazole derivatives attached on or doped into inert polymers are known to show photorefractive effect without external electric field, the origin of their asymmetric energy transfer in two-beam coupling experiments were unknown. We made the two-beam coupling experiment followed by sample translation and one-beam diffraction at 633 nm for thick films composed of 3-[(4-nitrophenyl)]azo-9H-carbazole-9-ethanol (NACzEtOH) and poly(methylmethacrylate), finding that photoinduced gratings grew in several minutes accompanied with phase displacement of the gratings, but the phase shift was not always synchronized with the refractive index modulation. We reformulated the Kogelnik's coupled-wave theory with strict energy conservation law for analysis. Comparison of the grating growth and erasure at 532 nm to Disperse Red 1 (DR1), the most well-known azo dye showed that the photoisomerization was dominant at this wavelength and that the azo-carbazole dyes were faster in response time and more resistive to erasure than DR1.

  1. The process of the reduction of azo dyes used in dyeing textiles on the basis of infrared spectroscopy analysis

    NASA Astrophysics Data System (ADS)

    Pielesz, A.

    1999-11-01

    Nowadays the world observes a widespread campaign against the use in yarn of dangerous, carcinogenic amines which penetrate human organisms. Their source in organisms is the process of biological reduction of azo dyes which are used in dyeing yarn. The current obligatory methods of aromatic amine identification are the widely understood chromatographic methods. In this work, the identification of amines through the fourier transform infrared spectroscopy has been suggested. The results of the experiments have allowed the use of the same method in aromatic amine identification.

  2. Polarization-dependent circular Dammann grating made of azo-dye-doped liquid crystals.

    PubMed

    Luo, Dan; Sun, Xiao Wei; Dai, Hai Tao; Demir, Hilmi Volkan

    2011-05-20

    A polarization-dependent circular Dammann grating (CDG) was generated from an azo-dye-doped liquid crystal (LC) cell. A simple multiexposure photo-alignment process was used to fabricate a binary phase LC CDG zone plane, which was composed of an odd zone with a twisted nematic LC structure and an even zone with a homogenous LC structure. A two-order CDG with equal-intensity rings was produced through a Fourier transform. The maximum zeroth and first diffraction orders of obtained CDG can be separately achieved by rotating the analyzer's polarization direction. The CDG using an azo-dye-doped LC cell can be used to generate diffractions by lasers in a broad wavelength range, hence expanding possible device applications.

  3. Removal of azo dye by a highly graphitized and heteroatom doped carbon derived from fish waste: Adsorption equilibrium and kinetics.

    PubMed

    Liu, Zhengang; Zhang, Fang; Liu, Tingting; Peng, Nana; Gai, Chao

    2016-11-01

    A highly graphitized and heteroatom doped porous carbon was prepared from fish waste in the present study. The morphology and chemical composition of the resultant porous carbon were characterized by SEM-EDS, TEM, BET, XRD and Raman measurement. The prepared porous carbon was employed as an adsorbent for acid orange 7, a typical azo dye, removal from aqueous solution. The results showed that the porous carbon had ultrahigh surface area of 2146 m(2)/g, a high degree of graphitization structure and naturally doped with nitrogen and phosphorous. The maximum adsorption capacity of acid orange 7 reached 285.71 mg/g due to unique property of the prepared porous carbon. In addition, acid orange 7 adsorption onto the porous carbon well followed pseudo-second-order kinetics model and acid orange 7 diffusion in micropores was the potential rate controlling step.

  4. Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes

    NASA Astrophysics Data System (ADS)

    Gromova, Yulia A.; Orlova, Anna O.; Maslov, Vladimir G.; Fedorov, Anatoly V.; Baranov, Alexander V.

    2013-10-01

    Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed.

  5. Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes.

    PubMed

    Gromova, Yulia A; Orlova, Anna O; Maslov, Vladimir G; Fedorov, Anatoly V; Baranov, Alexander V

    2013-10-31

    Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed.

  6. Kinetics of photoinduced ordering in azo-dye films: two-state and diffusion models.

    PubMed

    Kiselev, Alexei D; Chigrinov, Vladimir G; Kwok, Hoi-Sing

    2009-07-01

    We theoretically study the kinetics of photoinduced ordering in azo-dye photoaligning layers and present the results of modeling performed using two different phenomenological approaches. A phenomenological two-state model is deduced from the master equation for the one-particle distribution functions of an ensemble of two-level molecular systems by specifying the angular redistribution probabilities and by expressing the order parameter correlation functions in terms of the order parameter tensor. Using an alternative approach that describes light-induced reorientation of azo-dye molecules in terms of a rotational Brownian motion, we formulate the two-dimensional diffusion model as the free energy Fokker-Planck equation simplified for the limiting regime of purely in-plane reorientation. The models are employed to interpret the irradiation time dependence of the absorption order parameters defined in terms of the principal extinction (absorption) coefficients. Using the exact solution to the light transmission problem for a biaxially anisotropic absorbing layer, these coefficients are extracted from the absorbance-vs-incidence angle curves measured at different irradiation doses for the probe light linearly polarized parallel and perpendicular to the plane of incidence. It is found that, in the azo-dye films, the transient photoinduced structures are biaxially anisotropic whereas the photosteady and the initial states are uniaxial.

  7. Kinetics of photoinduced ordering in azo-dye films: Two-state and diffusion models

    SciTech Connect

    Kiselev, Alexei D.; Chigrinov, Vladimir G.; Kwok, Hoi-Sing

    2009-07-15

    We theoretically study the kinetics of photoinduced ordering in azo-dye photoaligning layers and present the results of modeling performed using two different phenomenological approaches. A phenomenological two-state model is deduced from the master equation for the one-particle distribution functions of an ensemble of two-level molecular systems by specifying the angular redistribution probabilities and by expressing the order parameter correlation functions in terms of the order parameter tensor. Using an alternative approach that describes light-induced reorientation of azo-dye molecules in terms of a rotational Brownian motion, we formulate the two-dimensional diffusion model as the free energy Fokker-Planck equation simplified for the limiting regime of purely in-plane reorientation. The models are employed to interpret the irradiation time dependence of the absorption order parameters defined in terms of the principal extinction (absorption) coefficients. Using the exact solution to the light transmission problem for a biaxially anisotropic absorbing layer, these coefficients are extracted from the absorbance-vs-incidence angle curves measured at different irradiation doses for the probe light linearly polarized parallel and perpendicular to the plane of incidence. It is found that, in the azo-dye films, the transient photoinduced structures are biaxially anisotropic whereas the photosteady and the initial states are uniaxial.

  8. Effects of different quinoid redox mediators on the anaerobic reduction of azo dyes by bacteria.

    PubMed

    Rau, Jorg; Knackmuss, Hans-Joachim; Stolz, Andreas

    2002-04-01

    The addition of quinoid redox mediators to anaerobically incubated cultures of various taxonomically different bacterial species resulted in significantly increased reduction rates for the azo dye amaranth. From different quinones tested, generally anthraquinone-2-sulfonate (AQS) and lawsone (2-hydroxy-1,4-naphthoquinone) caused the highest increase in the azoreductase activities. The effects of AQS and lawsone were studied in greater detail with Sphingomonas xenophaga BN6 and Escherichia coli K12. Both strains reduced the quinones under anaerobic conditions with significantly different relative activities. The chemically reduced forms of AQS, lawsone, and different other quinones were assayed for their ability to decolorize amaranth, and a good correlation between the redox potentials of the quinones and the reduction rates of the azo dyes was observed. The addition of AQS or lawsone also increased the ability of unacclimated sewage sludge to reduce azo dyes. Chemically pure lawsone could be replaced by the powdered leaves of the henna plant which contain significant amounts of lawsone.

  9. DFT Study of the Structure, Reactivity, Natural Bond Orbital and Hyperpolarizability of Thiazole Azo Dyes

    PubMed Central

    Osman, Osman I.

    2017-01-01

    The structure, reactivity, natural bond orbital (NBO), linear and nonlinear optical (NLO) properties of three thiazole azo dyes (A, B and C) were monitored by applying B3LYP, CAM-B3LYP and ωB97XD functionals with 6-311++G** and aug-cc-pvdz basis sets. The geometrical parameters, dipole moments, HOMO-LUMO (highest occupied molecular orbital, lowest unoccupied molecular orbital) energy gaps, absorption wavelengths and total hyperpolarizabilities were investigated in carbon tetrachloride (CCl4) chloroform (CHCl3), dichloromethane (CH2Cl2) and dimethlysulphoxide (DMSO). The donor methoxyphenyl group deviates from planarity with the thiazole azo moiety by ca. 38°; while the acceptor dicyanovinyl, indandione and dicyanovinylindanone groups diverge by ca. 6°. The HOMOs for the three dyes are identical. They spread over the methoxyphenyl donor moiety, the thiazole and benzene rings as π-bonding orbitals. The LUMOs are shaped up by the nature of the acceptor moieties. The LUMOs of the A, B and C dyes extend over the indandione, malononitrile and dicyanovinylindanone acceptor moieties, respectively, as π-antibonding orbitals. The HOMO-LUMO splittings showed that Dye C is much more reactive than dyes A and B. Compared to dyes A and B, Dye C yielded a longer maximum absorption wavelength because of the stabilization of its LUMOs relative to those of the other two. The three dyes show solvatochromism accompanied by significant increases in hyperpolarizability. The enhancement of the total hyperpolarizability of C compared to those of A and B is due to the cumulative action of the long π-conjugation of the indanone ring and the stronger electron-withdrawing ability of the dicyanovinyl moiety that form the dicyanovinylindanone acceptor group. These findings are facilitated by a natural bond orbital (NBO) technique. The very high total hyperpolarizabilities of the three dyes define their potent nonlinear optical (NLO) behaviour. PMID:28157151

  10. pI-Control in Comparative Fluorescence Gel Electrophoresis (CoFGE) using amphoteric azo dyes

    PubMed Central

    Hanneken, Marina; Šlais, Karel; König, Simone

    2015-01-01

    Amphoteric azo dyes were used for internal control of pI values in Comparative two-dimensional Fluorescence Gel Electrophoresis (CoFGE) [1]. The 2D-gel images of separated Escherichia coli proteins as well as those of colored amphoteric dyes separated by isoelectric focussing are presented. The latter were used to correct for variation in the first electrophoretic dimension and further improve protein coordinate assignment in 2D-gel electrophoresis. Data tables are supplied to demonstrate pI-value calibration and the effect on the assignment of protein spot coordinates. PMID:26217748

  11. pI-Control in Comparative Fluorescence Gel Electrophoresis (CoFGE) using amphoteric azo dyes.

    PubMed

    Hanneken, Marina; Šlais, Karel; König, Simone

    2015-06-01

    Amphoteric azo dyes were used for internal control of pI values in Comparative two-dimensional Fluorescence Gel Electrophoresis (CoFGE) [1]. The 2D-gel images of separated Escherichia coli proteins as well as those of colored amphoteric dyes separated by isoelectric focussing are presented. The latter were used to correct for variation in the first electrophoretic dimension and further improve protein coordinate assignment in 2D-gel electrophoresis. Data tables are supplied to demonstrate pI-value calibration and the effect on the assignment of protein spot coordinates.

  12. Limiting factor of the diffraction efficiency in azo-dye-doped polymers

    NASA Astrophysics Data System (ADS)

    Blanche, Pierre-Alexandre; Lemaire, Philippe C.; Maertens, Christophe; Dubois, P.; Jerome, R.

    1998-09-01

    We have used theoretical models to give an account of the photoinduced reorientation of the azo-dye molecules in polymers and the related macroscopic effects that are diffraction efficiency and photoinduced birefringence. Measurements have been carried out for three doped polymers presenting different behaviors according to the writing intensity and the sample temperature. Interpolation of the experimental data reveals that the limiting factor for the amplitude of the diffraction efficiency is principally the temperature of the samples, whereas then the sensitivity of the compounds seems to be only driven by the nature of the dye.

  13. Functional behavior of bio-electrochemical treatment system with increasing azo dye concentrations: Synergistic interactions of biocatalyst and electrode assembly.

    PubMed

    Sreelatha, S; Velvizhi, G; Naresh Kumar, A; Venkata Mohan, S

    2016-08-01

    Treatment of dye bearing wastewater through biological machinery is particularly challenging due to its recalcitrant and inhibitory nature. In this study, functional behavior and treatment efficiency of bio-electrochemical treatment (BET) system was evaluated with increasing azo dye concentrations (100, 200, 300 and 500mg dye/l). Maximum dye removal was observed at 300mg dye/l (75%) followed by 200mg dye/l (65%), 100mg dye/l (62%) and 500mg dye/l (58%). Concurrent increment in dye load resulted in enhanced azo reductase and dehydrogenase activities respectively (300mg dye/l: 39.6U; 4.96μg/ml). Derivatives of cyclic voltammograms also supported the involvement of various membrane bound redox shuttlers, viz., cytochrome-c, cytochrome-bc1 and flavoproteins during the electron transfer. Bacterial respiration during BET operation utilized various electron acceptors such as electrodes and dye intermediates with simultaneous bioelectricity generation. This study illustrates the synergistic interaction of biocatalyst with electrode assembly for efficient treatment of azo dye wastewater.

  14. Removal of azo dye from water by magnetite adsorption-Fenton oxidation.

    PubMed

    Rongcheng, Wu; Jiuhui, Qu

    2004-01-01

    The aim of this study is to highlight the possibility of using powder magnetite adsorption-Fenton oxidation as a method for removal of azo dye acid red B (ARB) from water. The adsorption properties of magnetite powder towards ARB were studied. The oxidation of adsorbed ARB and regeneration of magnetite adsorbent at the same time by Fenton reagent (hydrogen peroxide [H2O2] + iron (II) [Fe2+]) in another treatment unit with a smaller volume was also investigated. The efficiency of Fenton oxidation of ARB was compared for the reaction carried out in solution and on magnetite. The magnetic separation method was used to recover magnetite after adsorption or regeneration. The results indicated that the adsorption rate was fast. The capacity was strongly dependent on pH and inorganic anions, and pH 3.8 was optimal for the adsorption of ARB. The adsorption can be described well using the Langmuir model. The oxidation was more efficient for ARB adsorbed on magnetite than in solution. The adsorption capacity of magnetite increased significantly after regeneration, which was the result of an increase in surface area of the adsorbent and change of elemental ratio (oxygen:iron [O:Fe]) on the surface. The maximum adsorption capacity for ARB was 32.4 mg/g adsorbent.

  15. Decolorization and biodegradability of photocatalytic treated azo dyes and wool textile wastewater.

    PubMed

    Hu, C; Wang, Y

    1999-11-01

    The photodegradation and biodegradability have been investigated for four non-biodegradable commercial azo dyes, Reactive YellowKD-3G, Reactive Red 15, Reactive Red 24, Cationic Blue X-GRL, an indicator. Methyl Orange, and one industrial wool textile wastewater, using TiO2 suspensions irradiated with a medium pressure mercury lamp. The color removal of dyes solution and dyeing wastewater reached to above 90% within 20-30 min. of photocatalytic treatment. Biochemical oxygen demand (BOD) was found to increase, while chemical oxygen demand (COD), total organic carbon (TOC) decreased, so that the ratio of BOD5/COD of the wastewater increased from original zero up to 0.75. The result implies that photocatalytic oxidation enhanced the biodegradability of the dye-containing wastewater and therefore relationship between decolorization and biodegradability exists. When the color disappeared completely, the wastewater biodegraded normally and could be discharged for further treatment. The experimental results demonstrate that it is possible to combine photocatalysis with conventional biological treatment for the remedy of wastewater containing generally non-biodegradable azo dyes.

  16. Degradation of a model azo dye in submerged anaerobic membrane bioreactor (SAMBR) operated with powdered activated carbon (PAC).

    PubMed

    Baêta, B E L; Luna, H J; Sanson, A L; Silva, S Q; Aquino, S F

    2013-10-15

    This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73-94%) and color (90-94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ~50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.

  17. Determination of Aromatic Amines Released from Azo Dyes in Paper Packaging by Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Yang, Fei; Bian, Zhaoyang; Li, Zhonghao; Fan, Ziyan; Wang, Ying; Liu, ShanShan; Deng, Huimin; Tang, Gangling

    2016-09-01

    An LC-tandem MS (LC-MS/MS) method for the determination of 21 kinds of carcinogenic aromatic amines released from azo dyes in food wrappers was used in this research. Sodium dithionite was added to a citric acid buffer medium to reduce and decompose possible azo dyes. The extract was analyzed after liquid-liquid extraction (LLE) and dispersive SPE (d-SPE). The conditions for chromatographic separation, mass spectrum, LLE, and d-SPE were optimized. Under optimal conditions, the LOD was in the range of 0.13-0.35 mg/kg and LOQ in the range of 0.38-1.05 mg/kg, with the addition of standard recoveries of most aromatic amines being ≥80% and RSDs ≤10%. The recoveries for 2,4-diaminotoluene and 2,4-diaminoanisole were significantly lower, being ≤40%. The method was successfully used to analyze 30 practical samples, and the results showed that it is user-friendly, with high sensitivity, rapid control, and low matrix interference.

  18. UV-visible-DAD and 1H-NMR spectroscopy data fusion for studying the photodegradation process of azo-dyes using MCR-ALS.

    PubMed

    Fernández, Cristina; Pilar Callao, M; Larrechi, M Soledad

    2013-12-15

    The photodegradation process of three azo-dyes - Acid Orange 61, Acid Red 97 and Acid Brown 425 - was monitored simultaneously by ultraviolet-visible spectroscopy with diode array detector (UV-vis-DAD) and (1)H-nuclear magnetic resonance ((1)H-NMR). Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to obtain the concentration and spectral profile of the chemical compounds involved in the process. The analysis of the H-NMR data suggests there are more intermediate compounds than those obtained with the UV-vis-DAD data. The fusion of UV-vis-DAD and the (1)H-NMR signal before the multivariate analysis provides better results than when only one of the two detector signals was used. It was concluded that three degradation products were present in the medium when the three azo-dyes had practically degraded. This study is the first application of UV-vis-DAD and (1)H-NMR spectroscopy data fusion in this field and illustrates its potential as a quick method for evaluating the evolution of the azo-dye photodegradation process.

  19. Bioremediation of textile azo dyes by an aerobic bacterial consortium using a rotating biological contactor.

    PubMed

    Abraham, T Emilia; Senan, Resmi C; Shaffiqu, T S; Roy, Jegan J; Poulose, T P; Thomas, P P

    2003-01-01

    The degradation of an azo dye mixture by an aerobic bacterial consortium was studied in a rotating biological reactor. Laterite pebbles of particle size 850 microm to 1.44 mm were fixed on gramophone records using an epoxy resin on which the developed consortium was immobilized. Rate of degradation, BOD, biomass determination, enzymes involved, and fish bioassay were studied. The RBC has a high efficiency for dye degradation even at high dye concentrations (100 microg/mL) and high flow rate (36 L/h) at alkaline pH and salinity conditions normally encountered in the textile effluents. Bioassays (LD-50) using Thilapia fish in treated effluent showed that the percentage mortality was zero over a period of 96 h, whereas the mortality was 100% in untreated dye water within 26 h. Fish bioassay confirms that the effluent from RBC can be discharged safely to the environment.

  20. Biomineralization of azo dye bearing wastewater in periodic discontinuous batch reactor: Effect of microaerophilic conditions on treatment efficiency.

    PubMed

    Naresh Kumar, A; Nagendranatha Reddy, C; Venkata Mohan, S

    2015-01-01

    The present study illustrates the influence of microaerophilic condition on periodic discontinuous batch reactor (PDBR) operation in treating azo dye containing wastewater. The process performance was evaluated with the function of various dye load operations (50-750 mg/l) by keeping the organic load (1.6 kg COD/m(3)-day) constant. Initially, lower dye operation (50mg dye/l) resulted in higher dye [45 mg dye/l (90%)] and COD [SDR: 1.29 kg COD/m(3)-day (92%)] removal efficiencies. Higher dye load operation (750 mg dye/l) also showed non-inhibitory performance with respect to dye [600 mg dye/l (80%)] and COD [1.25 kg COD/m(3)-day (80%)] removal efficiencies. Increment in dye load showed increment in azo reductase and dehydrogenase activities (39.6 U; 4.96 μg/ml; 750 mg/l). UV-Vis spectroscopy (200-800 nm), FTIR and (1)H NMR studies revealed the disappearance of azo bond (-NN-). First derivative cyclic voltammogram supported the involvement of various membrane bound redox shuttlers, viz., cytochrome-C, cytochrome-bc1 and flavoproteins (FAD (H)).

  1. Synthesis, spectroscopic, thermal and electrochemical studies on thiazolyl azo based disperse dyes bearing coumarin

    NASA Astrophysics Data System (ADS)

    Özkütük, Müjgan; İpek, Ezgi; Aydıner, Burcu; Mamaş, Serhat; Seferoğlu, Zeynel

    2016-03-01

    In this study, seven novel thiazolyl azo disperse dyes (6a-g) were synthesized and fully characterized by FT-IR, 1H NMR, 13C NMR, and mass spectral techniques. The electronic absorption spectra of the dyes in solvents of different polarities cover a λmax range of 404-512 nm. The absorption properties of the dyes changed drastically upon acidification. This was due to the protonation of the nitrogen in the thiazole ring, which in turn increased the donor-acceptor interplay of the π system in the dyes, and therefore increased the absorption properties of the prepared dyes. Thermal analysis showed that these dyes are thermal stable up to 269 °C. Additionally, the electrochemical behavior of the dyes (6a-g) were investigated using cyclic voltammetric and chronoamperometric techniques, in the presence of 0.10 M tetrabutylammonium tetrafluoroborate, in dimethylsulfoxide, at a glassy carbon electrode. The number of transferred electrons, and the diffusion coefficient were determined by electrochemical methods. The results showed that, for all the dyes, one oxidation peak and two reduction peaks were observed.

  2. Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice.

    PubMed

    Ruf, J; Walter, P; Kandler, H; Kaufmann, A

    2012-01-01

    An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.

  3. Decolorization of Textile Dyes and Degradation of Mono-Azo Dye Amaranth by Acinetobacter calcoaceticus NCIM 2890.

    PubMed

    Ghodake, Gajanan; Jadhav, Umesh; Tamboli, Dhawal; Kagalkar, Anuradha; Govindwar, Sanjay

    2011-10-01

    Acinetobacter calcoaceticus NCIM 2890 (A. caloaceticus) was found to decolorize 20 different textile dyes of various classes. Decolorization of an azo dye amaranth was observed effectively (91%) at static anoxic condition, whereas agitated culture grew well but showed less decolorization (68%) within 48 h of incubation. Induction of intracellular and extracellular lignin peroxidase, intracellular laccase, dichlorophenol indophenol (DCIP) reductase and riboflavin reductase represented their involvement in the biodegradation of amaranth. The products obtained after degradation of Amaranth were characterized as naphthalene sulfamide, hydroxyl naphthalene diazonium and naphthalene diazonium. The germination and growth of Sorghum vulgare and Phaseolus mungo seeds, and the growth of E. coli and Bacillus substilis were not inhibited by the metabolic products of the dye.

  4. Decolorization of azo dyes under batch anaerobic and sequential anaerobic/aerobic conditions.

    PubMed

    Işik, Mustafa; Sponza, Delia Teresa

    2004-01-01

    Batch anaerobic and sequential anaerobic upflow anaerobic sludge blanket (UASB)/aerobic continuous stirred tank reactor (CSTR) were used to determine the color and COD removals under anaerobic/aerobic conditions. Two azo dyes namely "Reactive Black 5 (RB 5)," "Congo Red (CR)," and glucose as a carbon source were used for synthetic wastewater. The course of the decolorization process approximates to first order and zero order kinetics with respect to dye concentration for RB 5 and Congo Red azo dyes, respectively, in batch conditions. The decolorization kinetic constant (K0) values increased from 3.6 to 11.8 mg(L h)(-1) as increases in dye concentrations from 200 to 3200 mg L(-1) for CR. Increases in dye concentrations from 0 to 3200 mg L(-1) reduce the decolorization rate constant (k1) values from 0.0141 to 0.0019 h(-1) in batch studies performed with RB 5. Decolorization was achieved effectively under test conditions but ultimate decolorization of azo dyes was not observed at all dye concentrations in batch assay conditions. Dye concentrations of 100 mg L(-1) and 3000 mg L(-1) of glucose-COD containing basal medium were used for continuous studies. The effect of organic loadings and HRT, on the color removal efficiencies and methane gas productions were monitored. 94.1-45.4% COD and 79-73% color removal efficiencies were obtained at an organic system during decolorization of Reactive Black 5. 92.3-77.0% COD and 95.3-92.2% decolorization efficiencies were achieved at a organic loading rate of 1.03-6.65 kg (m3 day)(-1) and a HRT of 3.54-0.49 for Congo Red treatment. The results of this study showed that, although decolorization continued, COD removal efficiencies and methane gas production were depressed at high organic loadings under anaerobic conditions. Furthermore, VFA accumulation, alkalinity consumption, and methane gas percentage were monitored at organic loading as high as 2.49-4.74 kg (m3 day)(-1) and 24.60-30.62 kg (m3 day)(-1), respectively, through the

  5. Photocatalytic degradation of three azo dyes using immobilized TiO2 nanoparticles on glass plates activated by UV light irradiation: influence of dye molecular structure.

    PubMed

    Khataee, A R; Pons, M N; Zahraa, O

    2009-08-30

    In order to discuss the effect of chemical structure on photocatalysis efficiency, the photocatalytic degradation of three commercial textile dyes (C.I. Acid Orange 10 (AO10), C.I. Acid Orange 12 (AO12) and C.I. Acid Orange 8 (AO8)) with different structure and different substitute groups has been investigated using supported TiO(2) photocatalyst under UV light irradiation. All the experiments were performed in a circulation photochemical reactor equipped with a 15-W UV lamp emitted around 365nm. The investigated photocatalyst was industrial Millennium PC-500 (crystallites mean size 5-10nm) immobilized on glass plates by a heat attachment method. SEM images of the immobilized TiO(2) nanoparticles showed the good coating on the plates, after repeating the deposition procedure three times. Our results indicated that the photocatalytic decolorization kinetics of the dyes were in the order of AO10>AO12>AO8. Photocatalytic mineralization of the dyes was monitored by total organic carbon (TOC) decrease, changes in UV-vis spectra and ammonium ion formation. The dye solutions could be completely decolorized and effectively mineralized, with an average overall TOC removal larger than 94% for a photocatalytic reaction time of 6h. The nitrogen-to-nitrogen double bond of the azo dyes was transformed predominantly into NH(4)(+) ion. The kinetic of photocatalytic decolorization of the dyes was found to follow a first-order rate law. The photocatalysis efficiency was evaluated by figure-of-merit electrical energy per order (E(EO)).

  6. Synthesis of magnetic biocomposite for efficient adsorption of azo dye from aqueous solution.

    PubMed

    Sivashankar, R; Sathya, A B; Krishnakumar, Uma; Sivasubramanian, V

    2015-11-01

    A novel magnetic biocomposite was synthesized using metal chlorides and aquatic macrophytes by co-precipitation method. The resulting product, magnetic biocomposite was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The adsorption performance of the magnetic biocomposite was tested with removal of Metanil Yellow dye from aqueous solution. The effect of influencing parameters such as initial dye concentration, solution pH and agitation were investigated. The equilibrium isotherm was well described by the Langmuir model with the with maximum adsorption capacity of 90.91mg/g. Adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the magnetic biocomposite could efficiently adsorb the azo dyes from aqueous solution, and the spent adsorbents could be recovered completely by magnetic separation process. Therefore, the prepared magnetic biocomposite could thus be used as promising adsorbent for the removal of azo dyes from polluted water.

  7. Assessment of by-products of chlorination and photoelectrocatalytic chlorination of an azo dye.

    PubMed

    de Oliveira, Rafael Leite; Anderson, Marc A; Umbuzeiro, Gisela de Aragão; Zocolo, Guilherme Julião; Zanoni, Maria Valnice Boldrin

    2012-02-29

    The present work describes a more efficient methodology for the chlorination of water containing disperse dyes, where the chlorinated byproducts identified by mass spectra are compared. For this investigation, we tested the degradation of CI Disperse Blue 291 dye, 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide) a commercial azo dye with mutagenic properties. The present work evaluates the photoelectrocatalytic efficiency of removing the CI Disperse Blue 291 dye from a wastewater of the textile industry. We employed NaCl as a supporting electrolyte. It should be noted that photoelectrocatalytic techniques are non-conventional method of generating chlorine radicals. The by-products formed in this process were analyzed using spectrophotometry, liquid chromatography, dissolved organic carbon, mass spectral analysis and mutagenicity assays. The process efficiency was compared with the conventional chlorination process adopted during sewage and effluents treatment processes. This conventional chlorination process is less efficient in removing color, total organic carbon than the photoelectrochemistry technique. Furthermore, we shall demonstrate that the mutagenicity of the generated by-products obtained using photoelectrocatalysis is completely different from that obtained by the conventional oxidation of chloride ions in the drinking water treatment process.

  8. Pilot scale annular plug flow photoreactor by UV/H2O2 for the decolorization of azo dye wastewater.

    PubMed

    Shu, Hung-Yee; Chang, Ming-Chin

    2005-10-17

    A pilot scale annular plug flow photoreactor with thin gap size, which combines with UV irradiation and hydrogen peroxide, was employed to deal with colored dyeing wastewater treatment. In the experiment, a mono-azo dye acid orange 10 was the target compound. The experimental parameters such as flow rate, hydrogen peroxide dosage, UV input power, pH and dye initial concentrations in a pilot scale photoreactor with flow rate of 9.32 m3day(-1) were investigated. Ultimately, the degradation rates were calculated and compared with a 100-l batch reactor. In our plug flow photoreactor design, the degradation rate of acid orange 10 was 233 times higher than that of 100-l annular batch reactor with same UV light source. The residence time needed for 99% decolorizing of 100 l of 20 mgl(-1) acid orange 10 wastewater was 26.9 min for the thin gap plug flow reactor and was far shorter than that of batch reactor needed.

  9. Synthesis, structural elucidation, solvatochromism and spectroscopic properties of some azo dyes derived from 6-chloro-4-hydroxyquinoline-2(1H)-one

    NASA Astrophysics Data System (ADS)

    Rufchahi, E. O. Moradi; Gilani, A. Ghanadzadeh; Taghvaei, V.; Karimi, R.; Ramezanzade, N.

    2016-03-01

    Malondianilide (I) derived from p-chloroaniline was cyclized to 6-chloro-4-hydroxyquinoline-2(1H)-one (II) in moderately good yield using polyphosphoric acid as catalyst. This compound was then coupled with some diazotized aromatic amines to give the corresponding azo disperse dyes 1-12. A systematic study of the effect of solvent, acid, base and pH upon the electronic absorption spectra of the dyes 1-12 was carried out. In DMSO, DMF, CH3CN, CHCl3, EtOH and acidic media (CH3COOH, acidified EtOH) these dyes that theoretically may be involved in azo-hydrazone tautomerism have been detected only as hydrazone tautomers T1 and T2. The acidic dissociation constants of the dyes were measured in 80 vol% ethanol-water solution at room temperature and ionic strength of 0.1. The results were correlated by the Hammett-type equation using the substituent constants σx.

  10. Potential plant growth-promoting strain Bacillus sp. SR-2-1/1 decolorized azo dyes through NADH-ubiquinone:oxidoreductase activity.

    PubMed

    Mahmood, Faisal; Shahid, Muhammad; Hussain, Sabir; Shahzad, Tanvir; Tahir, Muhammad; Ijaz, Muhammad; Hussain, Athar; Mahmood, Khalid; Imran, Muhammad; Babar, Shahid Ali Khan

    2017-03-22

    In this study, a bacterial strain SR-2-1/1 was isolated from textile wastewater-irrigated soil for its concurrent potential of plant growth promotion and azo-dye decolorization. Analysis of 16S rRNA gene sequence confirmed its identity as Bacillus sp. The strain tolerated high concentrations (i.e. up to 1000mgL(-1)) of metals (Ni(2+), Cd(2+), Co(2+), Zn(2+), and Cr(6+)) and efficiently decolorized the azo dyes (i.e. reactive black-5, reactive red-120, direct blue-1 and congo red). It also demonstrated considerable in vitro phosphate solubilizing and 1-aminocyclopropane-1-carboxylic acid deaminase abilities at high metal and salt levels. Bioinformatics analysis of its 537bp azoreductase gene and deduced protein revealed that it decolorized azo dyes through NADH-ubiquinone:oxidoreductase enzyme activity. The deduced protein was predicted structurally and functionally different to those of its closely related database proteins. Thus, the strain SR-2-1/1 is a powerful bioinoculant for bioremediation of textile wastewater contaminated soils in addition to stimulation of plant growth.

  11. Adsorption of azo dyes from aqueous solution by the hybrid MOFs/GO.

    PubMed

    Li, Ling; Shi, Zhennan; Zhu, Hongyang; Hong, Wei; Xie, Fengwei; Sun, Keke

    2016-01-01

    In this work, a hybrid of chromium(III) terephthalate metal organic framework (MIL-101) and graphene oxide (GO) was synthesized and its performance in the removal of azo dyes (Amaranth, Sunset Yellow, and Carmine) from water was evaluated. The adsorption for azo dyes on MIL-101/GO was compared with that of MIL-101, and it was found that the addition of GO enhanced the stability of MIL-101 in water and increased the adsorption capacity. The maximum adsorption capacities of MIL-101/GO were 111.01 mg g(-1) for Amaranth, 81.28 mg g(-1) for Sunset Yellow, and 77.61 mg g(-1) for Carmine. The adsorption isotherms and kinetics were investigated, showing that the adsorption fits the Freundlich isotherm and the pseudo-second-order kinetic model. The recyclability of MIL-101/GO was shown by the regeneration by acetone. The high adsorption capability and excellent reusability make MIL-101/GO a competent adsorbent for the removal dyes from aqueous solution.

  12. Process and kinetics of azo dye decolourization in bioelectrochemical systems: effect of several key factors

    PubMed Central

    Yang, Hou-Yun; He, Chuan-Shu; Li, Lei; Zhang, Jie; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2016-01-01

    This study explored the influence of several key factors on the process and kinetics of azo dye decolourization in bioelectrochemical systems (BESs), including cathode potential, dissolved oxygen (DO) concentration of catholyte and biofilm formed on the cathode. The results show that azo dye methyl orange (MO) decolourization in the BES could be well described with the pseudo first-order kinetics. The MO decolourization efficiency increased from 0 to 94.90 ± 0.01% and correspondingly the reaction rate constant increased from 0 to 0.503 ± 0.001 h−1 with the decrease in cathodic electrode potential from −0.2 to −0.8 V vs Ag/AgCl. On the contrary, DO concentration of the catholyte had a negative impact on MO decolourization in the BES. When DO concentration increased from zero to 5.80 mg L−1, the MO decolourization efficiency decreased from 87.19 ± 4.73% to 27.77 ± 0.06% and correspondingly the reaction rate constant reduced from 0.207 ± 0.042 to 0.033 ± 0.007 h−1. Additionally, the results suggest that the biofilm formed on the cathode could led to an adverse rather than a positive effect on azo dye decolourization in the BES in terms of efficiency and kinetics. PMID:27270398

  13. Kinetic study of electro-Fenton oxidation of azo dyes on boron-doped diamond electrode.

    PubMed

    Almomani, Fares; Baranova, Elena A

    2013-01-01

    The present work compares electrochemical degradation of red and blue azo textile dyes in single- and two-compartment electrochemical cells in the presence of Fenton reagent (Fe2+) and using a boron-doped diamond anode. Degradation of both dyes was related to the concentration of dye, applied current density and the concentration of FeSO4 catalyst. Complete colour removal and approximately 91% of organic matter oxidation was achieved in a two-compartment electrochemical cell at an applied current density of 20 mA x cm(-2), pH of 3 and Fe(2+) ion concentration of 0.02 mM. Higher current density and reaction time were required to achieve the same removals in a one-compartment electrochemical cell. Dye degradation kinetics as well as chemical oxygen demand removal rate were successfully modelled to pseudo first-order kinetics. The apparent first-order rate constants (k(o)) for degradation of red dye with an initial concentration of 20, 40 and 60 ppm were found to be 2.67 +/- 0.16, 2.19 +/- 0.09 and 1.5 +/- 0.03 min(-1), and for blue dye at the same initial concentrations were 1.99 +/- 0.2, 0.95 +/- 0.02 and 0.71 +/- 0.030 min(-1), respectively.

  14. Genotoxicity studies on the azo dye Direct Red 2 using the in vivo mouse bone marrow micronucleus test.

    PubMed

    Rajaguru, P; Fairbairn, L J; Ashby, J; Willington, M A; Turner, S; Woolford, L A; Chinnasamy, N; Rafferty, J A

    1999-07-21

    The clastogenicity of the azo dye Direct Red 2 (DR2) has been investigated using the murine bone marrow micronucleus assay. A potent dose-dependent response was observed following oral gavage of DR2 up to 4 mg/kg, after which significant toxicity to the erythroid compartment was observed. The route of administration had a significant effect on the frequency of micronucleus formation: intraperitoneal injection was approximately two-fold less clastogenic than the equivalent dose delivered orally (p<0.05). The requirement for activation of DR2 by intestinal microflora was indicated by the fact that mice given acid-treated water prior to administration of DR2 showed a significant reduction (40%; p<0.001) in micronucleated polychromatic erythrocyte formation. The implications of these findings for the health and safety of occupationally exposed workers are discussed.

  15. Fe-based metallic glass catalyst with nanoporous surface for azo dye degradation.

    PubMed

    Deng, Z; Zhang, X H; Chan, K C; Liu, L; Li, T

    2017-05-01

    In this work, porous structures were introduced to the surface of Fe-based metallic glass ribbons for the first time by chemical treatment in order to increase the catalytic activity in the degradation of azo dyes. The results show that etching treatment in an HF solution with a volume concentration of 20% for 40 min leads to a porous structure on the FeSiBNb metallic glass with a dramatic increase in the specific surface area by 25 times. The much higher specific surface area of the porous ribbons greatly improves the catalytic activity in the degradation of Direct Blue 15 when compared with as-spun metallic ribbons.

  16. Optical phase conjugation in azo-dye doped chiral liquid crystal

    NASA Astrophysics Data System (ADS)

    Karpinski, Pawel; Miniewicz, Andrzej

    2012-10-01

    We report on optical phase conjugation phenomenon observed in chiral nematic liquid crystal showing band gap type Bragg reflection. The phase conjugate to the signal beam is observable only in the small temperature interval when the Bragg condition is fulfilled and only for circularly polarized light. The optical phase conjugation signals were observed at low cw laser light intensities (<100 mW/cm2, λ = 532 nm). Estimated value of third order optical susceptibility χ(3) = 2.8 × 10-17 m2/V2 is attributed to enhancement due to photoisomerisation of azo-dye (disperse red 1) inducing molecular reorientation process of liquid crystal molecules.

  17. Photoinduced grating formation in azo-dye-labeled phospholipid thin films by 244-nm light.

    PubMed

    Sharma, A; Dokhanian, M; Kassu, A; Parekh, Atul N

    2005-03-01

    Holographic gratings are recorded in azo-dye nitrobenzoxazole-labeled phospholipid thin films by use of 244-nm UV light. The gratings continue to grow for more than 1 h, even after the recording light is removed. The diffraction efficiency of these gratings shows extreme sensitivity to humidity and can increase reversibly by 2 orders of magnitude in air that is saturated with water vapor. This effect is related to the unique characteristics of phospholipid molecules that undergo hydration-dependent structural reorganization and self-assembly.

  18. Transflective spatial filter based on azo-dye-doped cholesteric liquid crystal films

    SciTech Connect

    Lin, T.-H.; Fuh, Andy Y.-G.

    2005-07-04

    This work demonstrates the feasibility of exploiting the photoisomerization effect in azo-dye-doped cholesteric liquid crystal (DDCLC) films with a concomitant decline of the phase transition temperature from the cholesteric to an isotropic phase (T{sub Ch-I}) as a spatial filter. The fabrication depends on the fact that the various intensities of the diffracted orders are responsible for the various degrees of transparency associated with the photoisomerized DDCLC film. High- and low-pass images in the Fourier optical signal process can be simultaneously observed via reflected and transmitted signals, respectively. A simulation is also performed, and the results are consistent closely with experimental data.

  19. Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes

    PubMed Central

    2013-01-01

    Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed. PMID:24172215

  20. Comparison of three combined sequencing batch reactor followed by enhanced Fenton process for an azo dye degradation: Bio-decolorization kinetics study.

    PubMed

    Azizi, A; Alavi Moghaddam, M R; Maknoon, R; Kowsari, E

    2015-12-15

    The purpose of this research was to compare three combined sequencing batch reactor (SBR) - Fenton processes as post-treatment for the treatment of azo dye Acid Red 18 (AR18). Three combined treatment systems (CTS1, CTS2 and CTS3) were operated to investigate the biomass concentration, COD removal, AR18 dye decolorization and kinetics study. The MLSS concentration of CTS2 reached 7200 mg/L due to the use of external feeding in the SBR reactor of CTS2. The COD concentration remained 273 mg/L and 95 mg/L (initial COD=3270 mg/L) at the end of alternating anaerobic-aerobic SBR with external feeding (An-A MSBR) and CTS2, respectively, resulting in almost 65% of Fenton process efficiency. The dye concentration of 500 mg/L was finally reduced to less than 10mg/L in all systems indicating almost complete AR18 decolorization, which was also confirmed by UV-vis analysis. The dye was removed following two successive parts as parts 1 and 2 with pseudo zero-order and pseudo first-order kinetics, respectively, in all CTSs. Higher intermediate metabolites degradation was obtained using HPLC analysis in CTS2. Accordingly, a combined treatment system can be proposed as an appropriate and environmentally-friendly system for the treatment of the azo dye AR18 in wastewater.

  1. Differential Expression of Antioxidant Enzymes During Degradation of Azo Dye Reactive black 8 in Hairy roots of Physalis minima L.

    PubMed

    Jha, Pamela; Modi, Nikita; Jobby, Renitta; Desai, Neetin

    2015-01-01

    The enzymes involved in the protection of plant metabolism in presence of azo dye was characterized by studying activities of the role of antioxidant enzymes in the hairy roots (HRs) of Physalis minima L. during degradation of an azo dye, Reactive Black 8 (RB8). When the HRs were exposed to RB8 (30 mg L(-1)), a  nine fold increase in SOD activity was observed after 24 h, while 22 and 50 fold increase in activity was observed for POX and APX respectively after 72 h, whereas there was no significant change in activity of CAT. The activation of different antioxidant enzymes at different time intervals under dye stress suggests the synchronized functioning of antioxidant machinery to protect the HRs from oxidative damage. FTIR analysis confirmed the degradation of dye and the non-toxic nature of metabolites formed after dye degradation was confirmed by phytotoxicity study.

  2. Efficient treatment of azo dye containing wastewater in a hybrid acidogenic bioreactor stimulated by biocatalyzed electrolysis.

    PubMed

    Wang, Hong-Cheng; Cheng, Hao-Yi; Wang, Shu-Sen; Cui, Dan; Han, Jing-Long; Hu, Ya-Ping; Su, Shi-Gang; Wang, Ai-Jie

    2016-01-01

    In this study, a novel scaled-up hybrid acidogenic bioreactor (HAB) was designed and adopted to evaluate the performance of azo dye (acid red G, ARG) containing wastewater treatment. Principally, HAB is an acidogenic bioreactor coupled with a biocatalyzed electrolysis module. The effects of hydraulic retention time (HRT) and ARG loading rate on the performance of HAB were investigated. In addition, the influent was switched from synthetic wastewater to domestic wastewater to examine the key parameters for the application of HAB. The results showed that the introduction of the biocatalyzed electrolysis module could enhance anoxic decolorization and COD (chemical oxygen demand) removal. The combined process of HAB-CASS presented superior performance compared to a control system without biocatalyzed electrolysis (AB-CASS). When the influent was switched to domestic wastewater, with an environment having more balanced nutrients and diverse organic matters, the ARG, COD and nitrogen removal efficiencies of HAB-CASS were further improved, reaching 73.3%±2.5%, 86.2%±3.8% and 93.5%±1.6% at HRT of 6 hr, respectively, which were much higher than those of AB-CASS (61.1%±4.7%, 75.4%±5.0% and 82.1%±2.1%, respectively). Moreover, larger TCV/TV (total cathode volume/total volume) for HAB led to higher current and ARG removal. The ARG removal efficiency and current at TCV/TV of 0.15 were 39.2%±3.7% and 28.30±1.48 mA, respectively. They were significantly increased to 62.1%±2.0% and 34.55±0.83 mA at TCV/TV of 0.25. These results show that HAB system could be used to effectively treat real wastewater.

  3. Decolorization of Azo, Triphenyl Methane, Heterocyclic, and Polymeric Dyes by Lignin Peroxidase Isoenzymes from Phanerochaete chrysosporium.

    PubMed

    Ollikka, P; Alhonmäki, K; Leppänen, V M; Glumoff, T; Raijola, T; Suominen, I

    1993-12-01

    The ligninolytic enzyme system of Phanerochaete chrysosporium decolorizes several recalcitrant dyes. Three isolated lignin peroxidase isoenzymes (LiP 4.65, LiP 4.15, and LiP 3.85) were compared as decolorizers with the crude enzyme system from the culture medium. LiP 4.65 (H2), LiP 4.15 (H7), and LiP 3.85 (H8) were purified by chromatofocusing, and their kinetic parameters were found to be similar. Ten different types of dyes, including azo, triphenyl methane, heterocyclic, and polymeric dyes, were treated by the crude enzyme preparation. Most of the dyes lost over 75% of their color; only Congo red, Poly R-478, and Poly T-128 were decolorized less than the others, 54, 46, and 48%, respectively. Five different dyes were tested for decolorization by the three purified isoenzymes. The ability of the isoenzymes to decolorize the dyes in the presence of veratryl alcohol was generally comparable to that of the crude enzyme preparation, suggesting that lignin peroxidase plays a major role in the decolorization and that manganese peroxidase is not required to start the degradation of these dyes. In the absence of veratryl alcohol, the decolorization activity of the isoenzymes was in most cases dramatically reduced. However, LiP 3.85 was still able to decolorize 20% of methylene blue and methyl orange and as much as 60% of toluidine blue O, suggesting that at least some dyes can function as substrates for isoenzyme LiP 3.85 but not to the same extent for LiP 4.15 or LiP 4.65. Thus, the isoenzymes have different specificities towards dyes as substrates.

  4. Decolorization of Azo, Triphenyl Methane, Heterocyclic, and Polymeric Dyes by Lignin Peroxidase Isoenzymes from Phanerochaete chrysosporium

    PubMed Central

    Ollikka, Pauli; Alhonmäki, Kirsi; Leppänen, Veli-Matti; Glumoff, Tuomo; Raijola, Timo; Suominen, Ilari

    1993-01-01

    The ligninolytic enzyme system of Phanerochaete chrysosporium decolorizes several recalcitrant dyes. Three isolated lignin peroxidase isoenzymes (LiP 4.65, LiP 4.15, and LiP 3.85) were compared as decolorizers with the crude enzyme system from the culture medium. LiP 4.65 (H2), LiP 4.15 (H7), and LiP 3.85 (H8) were purified by chromatofocusing, and their kinetic parameters were found to be similar. Ten different types of dyes, including azo, triphenyl methane, heterocyclic, and polymeric dyes, were treated by the crude enzyme preparation. Most of the dyes lost over 75% of their color; only Congo red, Poly R-478, and Poly T-128 were decolorized less than the others, 54, 46, and 48%, respectively. Five different dyes were tested for decolorization by the three purified isoenzymes. The ability of the isoenzymes to decolorize the dyes in the presence of veratryl alcohol was generally comparable to that of the crude enzyme preparation, suggesting that lignin peroxidase plays a major role in the decolorization and that manganese peroxidase is not required to start the degradation of these dyes. In the absence of veratryl alcohol, the decolorization activity of the isoenzymes was in most cases dramatically reduced. However, LiP 3.85 was still able to decolorize 20% of methylene blue and methyl orange and as much as 60% of toluidine blue O, suggesting that at least some dyes can function as substrates for isoenzyme LiP 3.85 but not to the same extent for LiP 4.15 or LiP 4.65. Thus, the isoenzymes have different specificities towards dyes as substrates. Images PMID:16349103

  5. ALKALINE RIBONUCLEASE ACTIVITY INCREASE IN RAT KIDNEY CORTEX AND LIVER AFTER TRYPAN BLUE AND OTHER AZO DYES ADMINISTRATION

    PubMed Central

    Rabinovitch, M.; Brentani, R.; Ferreira, S.; Fausto, N.; Maack, T.

    1961-01-01

    Acid azo dyes, most of them naphtholdisulfonic acid derivatives, were given intraperitoneally to rats and their effect on "alkaline" ribonuclease activity was studied in total homogenates of kidney cortex and liver. Acid treatment was used to release bound enzyme activity. Several of the dyes, including trypan blue, increased RNase activity in both organs 3 days after administration of single doses, while others, like Evans blue, were inactive. Activity was apparently bound to the sulfonic substitution in the 3, 6 positions in the naphthalene rings, substitutions in the benzidine rings being not critical. All of the active and most of the inactive compounds were taken up by tubule cells of kidney cortex and by reticular and parenchymal cells of liver. While the effect on both liver and kidney was obtained 1 day after trypan blue administration, RNase remained increased for only about 3 days in the first organ, and for at least a month in the second. However, repeated trypan blue doses increased liver enzyme activity for at least 9 days. Serum RNase activity was decreased after trypan blue administration. Ethionine administration together with trypan blue markedly blocked the effect of the dye on liver RNase activity; simultaneously given methionine partially reversed the action of the antimetabolite. This suggests that de novo synthesis of RNase is induced in liver by trypan blue. The action of ethionine on the kidney RNase response to trypan blue was less marked although significant; in view of the possible kidney uptake of the plasma enzyme, interpretation of this finding must be postponed. Results are discussed with reference to the mechanism of the structural specificity of the compounds used, cytological localization of the dyes and their mechanism of action on liver and kidney RNase. PMID:13738846

  6. Heterogeneous fenton degradation of azo dyes catalyzed by modified polyacrylonitrile fiber fe complexes: QSPR (quantitative structure peorperty relationship) study.

    PubMed

    Li, Bing; Dong, Yongchun; Ding, Zhizhong

    2013-07-01

    The amidoximated polyacrylonitrile (PAN) fiber Fe complexes were prepared and used as the heterogeneous Fenton catalysts for the degradation of 28 anionic water soluble azo dyes in water under visible irradiation. The multiple linear regression (MLR) method was employed to develop the quantitative structure property relationship (QSPR) model equations for the decoloration and mineralization of azo dyes. Moreover, the predictive ability of the QSPR model equations was assessed using Leave-one-out (LOO) and cross-validation (CV) methods. Additionally, the effect of Fe content of catalyst and the sodium chloride in water on QSPR model equations were also investigated. The results indicated that the heterogeneous photo-Fenton degradation of the azo dyes with different structures was conducted in the presence of the amidoximated PAN fiber Fe complex. The QSPR model equations for the dye decoloration and mineralization were successfully developed using MLR technique. MW/S (molecular weight divided by the number of sulphonate groups) and NN=N (the number of azo linkage) are considered as the most important determining factor for the dye degradation and mineralization, and there is a significant negative correlation between MW/S or NN=N and degradation percentage or total organic carbon (TOC) removal. Moreover, LOO and CV analysis suggested that the obtained QSPR model equations have the better prediction ability. The variation in Fe content of catalyst and the addition of sodium chloride did not alter the nature of the QSPR model equations.

  7. Evaluation of three reagent dosing strategies in a photo-Fenton process for the decolorization of azo dye mixtures.

    PubMed

    Prato-Garcia, D; Buitrón, Germán

    2012-05-30

    Three reagent dosing strategies used in the solar photo-assisted decolorization of a mixture of sulfonated dyes consisting of acid blue 113, acid orange 7 and acid red 151 were evaluated. Results demonstrated that the dosing strategy influenced both reagent consumption and the biodegradability and toxicity of the effluent. In one strategy (E(1)), the Fenton's reactants were dosed in a punctual mode, while in the other two strategies (E(2) an E(3)), the reactants were dosed continuously. In the E(2) strategy the reactants were dosed by varying the duration of the injection time. In the E(3) strategy, the reactants were dosed during 60 min at a constant rate, but with different concentrations. All cases showed that feeding the reactor between 40% and 60% of the maximal dose was sufficient to decolorize more than 90% of the mixture of azo dyes. The E(1) strategy was less effective for aromatic content reduction. Conversely, the continuous addition of the reagents (E(2) and E(3) strategies) improved the aromatic content removal. E(3) strategy was substantially more appropriate than E(1) strategy due to improved the effluent quality in two key areas: toxicity and biodegradability.

  8. UV-based processes for reactive azo dye mineralization.

    PubMed

    Peternel, Igor; Koprivanac, Natalija; Kusic, Hrvoje

    2006-02-01

    In the present study, advanced oxidation processes, UV/H2O2, UV/O3, and UV/H2O2/O3 have been applied to bleach and degrade organic dye C.I. Reactive Red 45 in water solution. Influence of pH and hydrogen peroxide dosage on process efficiency was investigated. The rate of color removal was studied by measuring the absorbance at the characteristic wavelength while mineralization rates were obtained on the basis of total organic carbon (TOC) and adsorbable organic halides (AOX) measurements. Complete bleaching was achieved by all applied processes after 60 min while the maximal mineralization extent depended on the reaction conditions for each of the processes. It has been found that UV/H2O2/O3 process was the most efficient with 61.1% TOC removal and 72.0% AOX removal, respectively, achieved after a 1-h treatment. Time required for complete mineralization of RR45 by UV/H2O2 and UV/H2O2/O3 processes was determined as well.

  9. 40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721.10108 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Naphthalenedisulfonic acid, hydrozy- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic)....

  10. 40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721.10108 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Naphthalenedisulfonic acid, hydrozy- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic)....

  11. 40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721.10108 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... Naphthalenedisulfonic acid, hydrozy- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic)....

  12. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    NASA Astrophysics Data System (ADS)

    Broglia, M. F.; Suarez, S.; Soldera, F.; Mücklich, F.; Barbero, C. A.; Bellingeri, R.; Alustiza, F.; Acevedo, D.

    2014-05-01

    The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  13. Microbial dynamics during azo dye degradation in a UASB reactor supplied with yeast extract

    PubMed Central

    Silva, S.Q.; Silva, D.C.; Lanna, M.C.S.; Baeta, B.E.L.; Aquino, S.F.

    2014-01-01

    The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal. PMID:25763018

  14. Reductive-degradation of carcinogenic azo dyes using Anacardium occidentale testa derived silver nanoparticles.

    PubMed

    Edison, Thomas Nesakumar Jebakumar Immanuel; Atchudan, Raji; Sethuraman, Mathur Gopalakrishnan; Lee, Yong Rok

    2016-09-01

    In the present work, reductive-degradation of azo dyes such as congo red (CR) and methyl orange (MO) was manifested using Anacardium occidentale testa derived silver nanoparticles (AgNPs) as a catalyst. The formation of highly stable AgNPs were visually confirmed by the appearance of yellow color and further substantiated by the existence of surface plasmon resonance (SPR) peak around 425nm. The effect of A. occidentale concentration, reaction time and pH in the formations of AgNPs was corroborated by UV-visible (UV-Vis) spectroscopy. The Fourier transform infrared (FT-IR) spectroscopic results proved that phytoconstituents of A. occidentale testa acts as a capping agent and thereby protects the AgNPs from aggregation. The crystalline nature of the AgNPs was validated from the XRD patterns. The average size of synthesized AgNPs was 25nm, with distorted spherical shape was ascribed from the high resolution transmission electron microscopic (HR-TEM) images. Due to the high stability of the as-synthesized AgNPs, they were utilized for the degradation of carcinogenic azo dyes such as CR and MO using NaBH4 and its catalytic activity was studied via UV-Vis spectroscopy. The results proved that extraordinary catalytic activity of synthesized AgNPs towards the reductive-degradation of both CR and MO.

  15. Multiple grating formation in photorefractive polymers with azo-dye chromophores

    NASA Astrophysics Data System (ADS)

    Smith, Mark A.; King, Nick R.; Mitchell, Geoffrey R.; O'Leary, Sean V.

    1996-10-01

    Photorefractive polymers which incorporate azo-dyes as the nonlinear chromophore element, can be used not only for generating gratings by the photorefractive effect, but also by photoisomerization of the azo-dye. In the latter mechanism, repeated trans-cis isomerization causes the chromophore molecules to become aligned at right angles to the laser polarization direction, thereby making the material birefringent. These two phenomena are to a large degree independent, and can be studied separately, by appropriate choice of polarization direction of the interacting beams. Furthermore, the diffraction efficiency of the photorefractive gratings is a very sensitive function of the poling field strength, while that of the photoisomerization gratings is less so. In this work, we investigate the components diffracted from each of these gratings formed in a hybrid photorefractive polymer material PVK:TNF:DEACST:disperse red 1. We then explore the possibility of performing some simple optical processing applications, exploiting the flexibility provided by this multiple grating process. A scheme for producing a novelty filter, which displays only the moving parts of a scene is considered. The limitations of these films for such processing applications are discussed.

  16. Decolorization of azo dye reactive black B by Bacillus cereus strain HJ-1.

    PubMed

    Liao, Chien-Sen; Hung, Chih-Hsin; Chao, Sung-Lin

    2013-02-01

    Reactive black B (RBB) is a group of azo dyes that are widely used in the textile industry. In this study, a new microbial strain was isolated from azo dye contaminated river sediment which is capable of degrading RBB. The strain was identified as Bacillus cereus strain HJ-1 by 16S rRNA gene sequences analysis. The optimal conditions for RBB decolorization by B. cereus strain HJ-1 are: 25°C, pH 8, 1 CMC of triton X-100, 0.15 g L(-1) of added yeast extract, 0.125 g L(-1) of added glucose and static culture. Then the toxicity of RBB on the green algae Chlorella vulgaris was determined. The results showed that the median effective concentration (EC(50)) of RBB for C. vulgaris is 48 mg L(-1) and toxicity will really decrease after decolorization. In the end, B. cereus strain HJ-1 was amended into the origin river sediment and analyzed the whole microbial community structure of river sediment samples by PCR-DGGE technique. The result showed that B. cereus strain HJ-1 could survive in the river sediment after 12 d of incubation. Based on this work, we hope that these findings could provide some useful information for applying the decolorization of RBB in our environment.

  17. Decolorization of azo dyes with Enterobacter agglomerans immobilized in different supports by using fluidized bed bioreactor.

    PubMed

    Moutaouakkil, Adnane; Zeroual, Youssef; Dzayri, Fatima Zohra; Talbi, Mohamed; Lee, Kangmin; Blaghen, Mohamed

    2004-02-01

    Immobilized cells of Enterobacter agglomerans, able to reduce azo dyes enzymatically, were used as a biocatalyst for the decolorization of synthetic medium containing the toxic azo dye methyl red (MR). This bacterial strain exhibits high ability to completely decolorize 100 mg/L of MR after only 6 h of incubation under aerobic conditions. Cells of E. agglomerans were immobilized in calcium alginate, polyacylamide, cooper beech, and vermiculite, and were used for the decolorization of MR from synthetic water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when E. agglomerans was entrapped in calcium alginate beads and was of about 3.04 mg MR/g cell/h with a 50% conversion time ( t(1/2)) of about 1.6 h. Moreover, immobilized cells in calcium alginate continuously decolorized MR even after seven repeated experiments without significant loss of activity, while polyacrylamide-, cooper beech-, and vermiculite-immobilized cells retained only 62, 15, and 13% of their original activity, respectively.

  18. Removal of anionic azo dyes from aqueous solution by functional ionic liquid cross-linked polymer.

    PubMed

    Gao, Hejun; Kan, Taotao; Zhao, Siyuan; Qian, Yixia; Cheng, Xiyuan; Wu, Wenli; Wang, Xiaodong; Zheng, Liqiang

    2013-10-15

    A novel functional ionic liquid based cross-linked polymer (PDVB-IL) was synthesized from 1-aminoethyl-3-vinylimidazolium chloride and divinylbenzene for use as an adsorbent. The physicochemical properties of PDVB-IL were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The adsorptive capacity was investigated using anionic azo dyes of orange II, sunset yellow FCF, and amaranth as adsorbates. The maximum adsorption capacity could reach 925.09, 734.62, and 547.17 mg/g for orange II, sunset yellow FCF and amaranth at 25°C, respectively, which are much better than most of the other adsorbents reported earlier. The effect of pH value was investigated in the range of 1-8. The result shows that a low pH value is found to favor the adsorption of those anionic azo dyes. The adsorption kinetics and isotherms are well fitted by a pseudo second-order model and Langmuir model, respectively. The adsorption process is found to be dominated by physisorption. The introduction of functional ionic liquid moieties into cross-linked poly(divinylbenzene) polymer constitutes a new and efficient kind of adsorbent.

  19. Effect of an azo dye on the performance of an aerobic granular sludge sequencing batch reactor treating a simulated textile wastewater.

    PubMed

    Franca, Rita D G; Vieira, Anabela; Mata, Ana M T; Carvalho, Gilda S; Pinheiro, Helena M; Lourenço, Nídia D

    2015-11-15

    This study analyzed the effect of an azo dye (Acid Red 14) on the performance of an aerobic granular sludge (AGS) sequencing batch reactor (SBR) system operated with 6-h anaerobic-aerobic cycles for the treatment of a synthetic textile wastewater. In this sense, two SBRs inoculated with AGS from a domestic wastewater treatment plant were run in parallel, being one supplied with the dye and the other used as a dye-free control. The AGS successfully adapted to the new hydrodynamic conditions forming smaller, denser granules in both reactors, with optimal sludge volume index values of 19 and 17 mL g(-1) after 5-min and 30-min settling, respectively. As a result, high biomass concentration levels and sludge age values were registered, up to 13 gTSS L(-1) and 40 days, respectively, when deliberate biomass wastage was limited to the sampling needs. Stable dye removal yields above 90% were attained during the anaerobic reaction phase, confirmed by the formation of one of the aromatic amines arising from azo bond reduction. The control of the sludge retention time (SRT) to 15 days triggered a 30% reduction in the biodecolorization yield. However, the increase of the SRT values back to levels above 25 days reverted this effect and also promoted the complete bioconversion of the identified aromatic amine during the aerobic reaction phase. The dye and its breakdown products did not negatively affect the treatment performance, as organic load removal yields higher than 80% were attained in both reactors, up to 77% occurring in the anaerobic phase. These high anaerobic organic removal levels were correlated to an increase of Defluviicoccus-related glycogen accumulating organisms in the biomass. Also, the capacity of the system to deal with shocks of high dye concentration and organic load was successfully demonstrated. Granule breakup after long-term operation only occurred in the dye-free control SBR, suggesting that the azo dye plays an important role in improving granule

  20. Decolorization and mineralization of Allura Red AC azo dye by solar photoelectro-Fenton: Identification of intermediates.

    PubMed

    Thiam, Abdoulaye; Sirés, Ignasi; Centellas, Francesc; Cabot, Pere Lluís; Brillas, Enric

    2015-10-01

    The degradation of 2.5L of Allura Red AC solutions in sulfate medium containing 0.50mM Fe(2+) has been studied by solar photoelectro-Fenton (SPEF) using a flow plant equipped with a Pt/air-diffusion cell and a solar photoreactor. Comparative electro-Fenton treatment yielded rapid total decolorization but poor mineralization, since most products were slowly destroyed by OH formed from Fenton's reaction between Fe(2+) and H2O2 generated at the air-diffusion cathode. In contrast, the potent action of UV radiation from sunlight in SPEF allowed the rapid photolysis of recalcitrant intermediates, thus giving rise to a quick mineralization. Sulfate and nitrate ions, along with a large proportion of volatile N-derivatives, were always released. The increase in current density and decrease in azo dye concentration accelerated the decolorization and mineralization in SPEF, although lower current efficiency and greater specific energy consumption were obtained. The most cost-effective SPEF treatment was found for 460 mg L(-1) azo dye in 0.05 M Na2SO4 at 50 mA cm(-2), which yielded 95% mineralization with 81% current efficiency and 8.50 kW h m(-3). No significant effect of sulfate concentration was found. Up to 16 aromatic intermediates and 11 short-chain carboxylic acids, including oxalic and oxamic as the most persistent ones, were detected by GC-MS and HPLC. The large oxidation ability of SPEF can be explained by the quick photolysis of Fe(III)-oxalate complexes and other undetected intermediates.

  1. Synthesis of MoO{sub 3} nanoparticles for azo dye degradation by catalytic ozonation

    SciTech Connect

    Manivel, Arumugam; Lee, Gang-Juan; Chen, Chin-Yi; Chen, Jing-Heng; Ma, Shih-Hsin; Horng, Tzzy-Leng; Wu, Jerry J.

    2015-02-15

    Highlights: • Synthesis of one-dimensional MoO{sub 3} nanostructures using hydrothermal, microwave, and sonochemical methods. • Sonochemical synthesized MoO{sub 3} presents the best efficiency for the dye removal by catalytic ozonation. • Efficient environmental remediation process. - Abstract: One-dimensional molybdenum trioxide nanostructures were prepared in three different approaches, including thermal, microwave, and sonochemical methods. The physicochemical properties of the obtained MoO{sub 3} nanoparticles were investigated by diffused reflectance spectroscopy, X-ray diffraction analysis, field emission scanning electron microscopy, high resolution transmission electron microscopy, and Brunauer–Emmett–Teller surface area analysis. Among the methods as investigated, sonochemical synthesis gave well-dispersed fine MoO{sub 3} nanoparticles compared with the other approaches. All the synthesized MoO{sub 3} nanostructures were examined for the catalytic ozonation to degrade azo dye in aqueous environment. Different performances were obtained for the catalyst prepared in different methods and the catalytic efficiencies were found to be the order of sonochemical, microwave, and then thermal methods. The sonochemical MoO{sub 3} catalyst allowed the total dye removal within 20 min and its good performance was justified according to their higher surface area with higher number of active sites that provide effective dye interaction for better degradation.

  2. Statistical optimization, interaction analysis and desorption studies for the azo dyes adsorption onto chitosan films.

    PubMed

    Rêgo, T V; Cadaval, T R S; Dotto, G L; Pinto, L A A

    2013-12-01

    Chitosan films (CF) were applied to remove azo dyes (tartrazine and amaranth) from aqueous solutions by adsorption. CF were prepared by casting technique and characterized. Response surface methodology was employed to optimize the adsorption process as a function of pH (2, 3 and 4) and CF concentration (100, 150 and 200 mg L(-1)). The possible interactions CF-dyes were investigated by Fourier transform infrared spectroscopy, dispersive energy X-ray spectroscopy, thermogravimetric analysis and color parameters. Adsorption-desorption cycles were also performed. The more appropriate conditions for the adsorption of both dyes were pH of 2 and CF concentration of 100 mg L(-1). Under these conditions, the tartrazine and amaranth adsorption capacities were 413.8 and 278.3 mg g(-1), respectively. The interactions between the CF protonated amino groups and anionic form of the dyes at pH 2 were confirmed. Desorption experiments showed that the CF can keep its adsorption capacity maximum for two cycles.

  3. Bioelectricity Generation and Bioremediation of an Azo-Dye in a Microbial Fuel Cell Coupled Activated Sludge Process

    PubMed Central

    Khan, Mohammad Danish; Abdulateif, Huda; Ismail, Iqbal M.; Sabir, Suhail; Khan, Mohammad Zain

    2015-01-01

    Simultaneous bioelectricity generation and dye degradation was achieved in the present study by using a combined anaerobic-aerobic process. The anaerobic system was a typical single chambered microbial fuel cell (SMFC) which utilizes acid navy blue r (ANB) dye along with glucose as growth substrate to generate electricity. Four different concentrations of ANB (50, 100, 200 and 400 ppm) were tested in the SMFC and the degradation products were further treated in an activated sludge post treatment process. The dye decolorization followed pseudo first order kinetics while the negative values of the thermodynamic parameter ∆G (change in Gibbs free energy) shows that the reaction proceeds with a net decrease in the free energy of the system. The coulombic efficiency (CE) and power density (PD) attained peak values at 10.36% and 2,236 mW/m2 respectively for 200 ppm of ANB. A further increase in ANB concentrations results in lowering of cell potential (and PD) values owing to microbial inhibition at higher concentrations of toxic substrates. Cyclic voltammetry studies revealed a perfect redox reaction was taking place in the SMFC. The pH, temperature and conductivity remain 7.5–8.0, 27(±2°C and 10.6–18.2 mS/cm throughout the operation. The biodegradation pathway was studied by the gas chromatography coupled with mass spectroscopy technique, suggested the preferential cleavage of the azo bond as the initial step resulting in to aromatic amines. Thus, a combined anaerobic-aerobic process using SMFC coupled with activated sludge process can be a viable option for effective degradation of complex dye substrates along with energy (bioelectricity) recovery. PMID:26496083

  4. Biodecolorization of a food azo dye by the deep sea Dermacoccus abyssi MT1.1(T) strain from the Mariana Trench.

    PubMed

    Lang, Weeranuch; Sirisansaneeyakul, Sarote; Martins, Lígia O; Ngiwsara, Lukana; Sakairi, Nobuo; Pathom-aree, Wasu; Okuyama, Masayuki; Mori, Haruhide; Kimura, Atsuo

    2014-01-01

    This study reports the characterization of the ability of Dermacoccus spp. isolated from the deepest point of the world's oceans for azo dye decolorization. A detailed investigation of Dermacoccus abyssi MT1.1(T) with respect to the azoreductase activity and enzymatic mechanism as well as the potential role of the bacterial strain for biocleaning of industrial dye baths is reported. Resting cells with oxygen-insensitive azoreductase resulted in the rapid decolorization of the polysulfonated dye Brilliant Black BN (BBN) which is a common food colorant. The highest specific decolorization rate (vs) was found at 50 °C with a moderately thermal tolerance for over 1 h. Kinetic analysis showed the high rates and strong affinity of the enzymatic system for the dye with a Vmax = 137 mg/g cell/h and a Km = 19 mg/L. The degradation of BBN produces an initial orange intermediate, 8-amino-5-((4-sulfonatophenyl)diazenyl)naphthalene-2-sulfonic acid, identified by mass spectrometry which is later converted to 4-aminobenzene sulfonic acid. Nearly 80% of the maximum vs is possible achieved in resting cell treatment with the salinity increased up to 5.0% NaCl in reaction media. Therefore, this bacterial system has potential for dye decolorization bioprocesses occurring at high temperature and salt concentrations e.g. for cleaning dye-containing saline wastewaters.

  5. Catalytic wet peroxide oxidation of azo dye (Direct Blue 15) using solvothermally synthesized copper hydroxide nitrate as catalyst.

    PubMed

    Zhan, Yuzhong; Zhou, Xiang; Fu, Bei; Chen, Yiliang

    2011-03-15

    Copper hydroxide nitrate (Cu(2)(OH)(3)NO(3)) was synthesized solvothermally in anhydrous ethanol and characterized by XRD, FTIR, TG-DTA and SEM. The peroxide degradation of an azo dye (Direct Blue 15) on this material was evaluated by examining catalyst loading, initial pH, hydrogen peroxide dosage, initial dye concentration and temperature. The leaching of Cu from the copper hydroxide nitrate during the reaction was also measured. The copper hydroxide nitrate synthesized solvothermally, which was of a novel spherical morphology with complex secondary structures and contained high-dispersed Cu(2)O impurity, showed good performance for oxidation degradation of the azo dye, especially high catalytic activity, high utilization of hydrogen peroxide and a wide pH range, whereas the copper hydroxide nitrate synthesized by the direct reaction of copper nitrate and sodium hydroxide showed low catalytic activity.

  6. Preparation and Absorption Spectral Property of a Multifunctional Water-Soluble Azo Compound with D-π-A Structure, 4-(4- Hydroxy-1-Naphthylazo)Benzoic Acid

    NASA Astrophysics Data System (ADS)

    Hu, L.; Lv, H.; Xie, C. G.; Chang, W. G.; Yan, Z. Q.

    2015-07-01

    A multifunctional water-soluble azo dye with the D-π-A conjugated structure, 4-(4-hydroxy-1-naphthylazo) benzoic acid ( HNBA), was designed and synthesized using 1-naphanol as the electron donator, benzoic acid as the electron acceptor, and -N=N- as the bridging group. After its structure was characterized by FTIR, 1H NMR, and element analysis, the UV-Vis absorption spectral performance of the target dye was studied in detail. The results showed that the dye, combining hydroxyl group, azo group, and carboxyl group, possessed excellent absorption spectral properties (ɛ = 1.2·104 l·mol-1·cm-1) changing with pH and solvents. In particular, in polar and protonic water, it had excellent optical response to some metal ions, i.e., Fe3+ and Pb2+, which might make it a latent colorimetric sensor for detecting heavy metal ions.

  7. Linearly and circularly polarized laser photoinduced molecular order in azo dye doped polymer films

    NASA Astrophysics Data System (ADS)

    Saad, Bendaoud

    2017-03-01

    Photo-induced behavior of Azo Disperse one (AZD1) doped Poly(Methyl MethAcrylate) (PMMA) using both linear and circular polarized light is studied. The anisotropy is not erased by the circular polarization light. The circular polarization light combined with relatively long lifetime of the cis state in azo dye doped polymers activate all transverse directions of the angular hole burning through the spot in the film inducing anisotropy. Under circular polarized light, there is no orientation perpendicularly to the helex described by the rotating electric field vector, trans molecules reorients in the propagation direction of the pump beam. The polarization state of the probe beam after propagation through the pumped spot depends strongly on the angle of incidence of both pump and probe beams on the input face. In the case where circular polarized pump and probe beams are under the same angle of incidence, the probe beam "sees" anisotropic film as if it is isotropic. Results of this work shows the possibility to reorient azobenzene-type molecules in two orthogonal directions using alternately linearly and circularly polarized beams.

  8. Formation of photo-induced index grating in azo-carbazole dye-doped polymer

    NASA Astrophysics Data System (ADS)

    Kawabe, Yutaka; Fukuzawa, Kodai; Uemura, Takuya; Matsuura, Katsufumi; Yoshikawa, Toshio; Nishide, Jun-ichi; Sasabe, Hiroyuki

    2012-10-01

    An azo-carbazole dye, 3-[(4-Nitrophenyl)azo]-9H-carbazole-9-ethanol (NACzEtOH), and its relatives doped in polyacrylate films have been known to show `photorefractive' effect without external electric field even in symmetric optical alignment. We have already observed strong energy transfer due to phase-shifted grating by two-beam coupling experiments made for NACzEtOH doped PMMA films. Although the operation mechanism is still unknown, the high efficiency of diffraction is very promising for the application to real-time holography. For the convenience of analysis, we modified Kogelnik's theory for thick grating by correcting the constraint condition and applied it to evaluate refractive index modulation and other parameters quantitatively. In order to clarify the operation mechanism, we conducted the writing and erasing of gratings by using red and green laser beams and analyzed the diffraction magnitude and response dynamics, showing that the response time strongly depended on the writing wavelength, and that the grating formation and its phase shift were not always synchronized.

  9. Electrochemical oxidation of an azo dye in aqueous media investigation of operational parameters and kinetics.

    PubMed

    Parsa, J Basiri; Rezaei, M; Soleymani, A R

    2009-09-15

    In this research two types of electrochemical reactors for the treatment of simulated wastewaters containing Direct blue 71 azo dye (DB71) were used: (1) Laboratory scale undivided electrolysis cell system (450 mL volume) with one 2 cm x 2 cm platinum plate as the anode placed in the middle of the cell and two 2 cm x 8 cm steel plates (SS-304) as cathodes placed in the sides of the cell 2 cm from the central anode. (2) Pilot scale reactor (9L volume), equipped with two 3 cm x 23 cm stainless steel plates as anode and cathode, with distance of 3 cm apart. The influence of supporting electrolyte, applied voltage and pH were studied. The UV-vis spectra of samples during the electrochemical oxidation showed the rapid decolorization of the dye solution. During the process, the COD and current were measured in order to evaluate the degree of mineralization, energy consumption, current and anode efficiencies. The optimum supporting electrolyte and applied voltage were NaCl (5 g L(-1)) and 15 V. Using the lab scale reactor resulted in complete decolorization and mineralization of the dye solutions after ca. 90 and 120 min, respectively. Similar results were obtained using the pilot plant reactor under the same conditions. The good fit of the data to pseudo-first-order kinetics for COD removal at all applied voltages (except 20 V) was taken as proof of the involvement of indirect oxidation pathways in the process.

  10. Biphotonic-induced reorientation inversion in azo-dye-doped liquid crystal films.

    PubMed

    Lin, Hui-Chi; Chu, Chia-Wei; Li, Ming-Shian; Fuh, Andy Ying-Guey

    2011-07-04

    The reorientation inversion of liquid crystal molecules in azo-dye-doped liquid crystal (ADDLC) films irradiated by biphotonic (green and red light) lasers is studied using the self-phase-modulation method. The results show that the induced change of refractive index (∆n) in an ADDLC cell illuminated with a fixed intensity of green light increases with the red-light intensity. Notably, the value of ∆n is initially negative, and becomes positive when the intensity of the red laser is increasing. It is due to the fact that an extra positive torque is exerted on the LCs, which is produced by cis-isomers upon absorbing red light to compensate the negative torque induced by the excitation of the green light.

  11. Evaluation of in vitro efficacy for decolorization and degradation of commercial azo dye RB-B by Morganella sp. HK-1 isolated from dye contaminated industrial landfill.

    PubMed

    Pathak, Hilor; Soni, Dhaval; Chauhan, Kishor

    2014-06-01

    Reactive Black-B (RB-B) - one of the multi-sulphonated reactive azo dye - is being used extensively in textile as well as paper industries. Reactive azo dyes comprise of a significant group of synthetic compounds categorized as xenobiotics and its abatement from the environment still remains a challenge. In the present study, a newly isolated indigenous bacterial strain Morganella sp. HK-1 was exploited for its ability to decolorize and degrade RB-B dye. The isolate completely degraded RB-B (20 g L(-1)) within 24h under static conditions. Furthermore, the visible and FTIR spectral analysis established the bio-degradation of RB-B. The degraded metabolites of RB-B by Morganella sp. HK-1 were identified by GC-MS analysis as disodium 3,4,6-triamino-5-hydroxynaphthalene-2,7-disulfonate, 4-aminophenylsulfonylethyl hydrogen sulfate, naphthalene-1-ol, aniline and benzene. Based on this information, a putative pathway of degradation of RB-B by Morganella sp. HK-1 has been proposed. This study is the first report on elucidation of mechanism of bacterial degradation of RB-B dye. Furthermore, phytotoxicity, genotoxicity and aquatic acute toxicity studies of the parent dye and the bio-degraded dye products revealed drastic reduction in the toxicity of metabolites as compared to the parent dye. This implies that the biotreatment of the dye is of non-toxic nature. This study thus indicates the effectiveness of Morganella sp. HK-1 for the treatment of textile effluents containing sulphonated azo dyes.

  12. Aerobic degradation of a mixture of azo dyes in a packed bed reactor having bacteria-coated laterite pebbles.

    PubMed

    Senan, Resmi C; Shaffiqu, T S; Roy, J Jegan; Abraham, T Emilia

    2003-01-01

    A microbial consortium capable of aerobic degradation of a mixture of azo dyes consisting of two isolated strains (RRL,TVM) and one known strain of Pseudomonas putida (MTCC 1194) was immobilized on laterite stones. The amount of bacterial biomass attached to the laterite stones was 8.64 g per 100 g of the stone on a dry weight basis. The packed bed reactor was filled with these stones and had a total capacity of 850 mL and a void volume of 210 mL. The feed consisted of an equal mixture of seven azo dyes both in water as well as in a simulated textile effluent, at a pH of 9.0 and a salinity of 900 mg/L. The dye concentrations of influent were 25, 50, and 100 microg/mL. The residence time was varied between 0.78 and 6.23 h. It was found that at the lowest residence time 23.55, 45.73, and 79.95 microg of dye was degraded per hour at an initial dye concentration of 25, 50, and 100 microg, respectively. The pH was reduced from 9.0 to 7.0. Simulated textile effluent containing 50 microg/mL dye was degraded by 61.7%. Analysis of degradation products by TLC and HPLC showed that the dye mixture was degraded to nontoxic smaller molecules. The bacteria-coated pebbles were stable, there was no washout even after 2 months, and the reactor was found to be suitable for the aerobic degradation of azo dyes.

  13. Isolation and Characterization of Paracoccus sp. GSM2 Capable of Degrading Textile Azo Dye Reactive Violet 5

    PubMed Central

    Bheemaraddi, Mallikarjun C.; Shivannavar, Channappa T.; Gaddad, Subhashchandra M.

    2014-01-01

    A potential bacterial strain GSM2, capable of degrading an azo dye Reactive Violet 5 as a sole source of carbon, was isolated from textile mill effluent from Solapur, India. The 16S rDNA sequence and phenotypic characteristics indicated an isolated organism as Paracoccus sp. GSM2. This strain exhibited complete decolorization of Reactive Violet 5 (100 mg/L) within 16 h, while maximally it could decolorize 800 mg/L of dye within 38 h with 73% decolorization under static condition. For color removal, the most suitable pH and temperature were pH 6.0–9.0 and 25–40°C, respectively. The isolate was able to decolorize more than 70% of five structurally different azo dyes within 38 h. The isolate is salt tolerant as it can bring out more than 90% decolorization up to a salt concentration of 2% (w/v). UV-Visible absorption spectra before and after decolorization suggested that decolorization was due to biodegradation and was further confirmed by FT-IR spectroscopy. Overall results indicate the effectiveness of the strain GSM2 explored for the treatment of textile industry effluents containing various azo dyes. To our knowledge, this could be the first report on biodegradation of Reactive Violet 5 by Paracoccus sp. GSM2. PMID:24883397

  14. Isolation and characterization of Paracoccus sp. GSM2 capable of degrading textile azo dye Reactive Violet 5.

    PubMed

    Bheemaraddi, Mallikarjun C; Patil, Santosh; Shivannavar, Channappa T; Gaddad, Subhashchandra M

    2014-01-01

    A potential bacterial strain GSM2, capable of degrading an azo dye Reactive Violet 5 as a sole source of carbon, was isolated from textile mill effluent from Solapur, India. The 16S rDNA sequence and phenotypic characteristics indicated an isolated organism as Paracoccus sp. GSM2. This strain exhibited complete decolorization of Reactive Violet 5 (100 mg/L) within 16 h, while maximally it could decolorize 800 mg/L of dye within 38 h with 73% decolorization under static condition. For color removal, the most suitable pH and temperature were pH 6.0-9.0 and 25-40 °C, respectively. The isolate was able to decolorize more than 70% of five structurally different azo dyes within 38 h. The isolate is salt tolerant as it can bring out more than 90% decolorization up to a salt concentration of 2% (w/v). UV-Visible absorption spectra before and after decolorization suggested that decolorization was due to biodegradation and was further confirmed by FT-IR spectroscopy. Overall results indicate the effectiveness of the strain GSM2 explored for the treatment of textile industry effluents containing various azo dyes. To our knowledge, this could be the first report on biodegradation of Reactive Violet 5 by Paracoccus sp. GSM2.

  15. Selective recognition and discrimination of water-soluble azo dyes by a seven-channel molecularly imprinted polymer sensor array.

    PubMed

    Long, Zerong; Lu, Yi; Zhang, Mingliang; Qiu, Hongdeng

    2014-10-01

    A seven-channel molecularly imprinted polymer sensor array was prepared and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-Vis spectroscopy, and nitrogen physisorption studies. The results revealed that the imprinted polymers have distinct-binding affinities from those of structurally similar azo dyes. Analysis of the UV-Vis spectral response patterns of the seven dye analytes against the imprinted polymer array suggested that the different selectivity patterns of the array were closely connected to the imprinting process. To evaluate the effectiveness of the array format, the binding of a series of analytes was individually measured for each of the seven polymers, made with different templates (including one control polymer synthesized without the use of a template). The response patterns of the array to the selected azo dyes were processed by canonical discriminant analysis. The results showed that the molecularly imprinted array was able to discriminate each analyte with 100% accuracy. Moreover, the azo dyes in two real samples, spiked chrysoidin in smoked bean curd extract and Fanta lime soda (containing tartrazine), were successfully classified by the array.

  16. Study of azo dye decolorization and determination of cathode microorganism profile in air-cathode microbial fuel cells.

    PubMed

    Kumru, Mert; Eren, Hilal; Catal, Tunc; Bermek, Hakan; Akarsubaşi, Alper Tunga

    2012-09-01

    Five textile azo dyes, as part of an artificial mixture, were treated in single-chamber air-cathode microbial fuel cells while simultaneously utilizing acetate for electricity production. Remazol Black, Remazol Brilliant Blue, Remazol Turquoise Blue, Reactive Yellow and Reactive Red at concentrations of 40 or 80 mg L(-1) were decolorized to a similar extent, at averages of 78, 95, 53, 93 and 74%, respectively, in 24 hours. During the process of decolorization, electricity generation from acetate oxidation continued. Power densities obtained in the presence of textile dyes ranged from 347 to 521 mW m(-2) at the current density range of 0.071 - 0.086 mA cm(-2). Microbial community analyses of cathode biofilm exhibited dynamic changes in abundant species following dye decolorization. Upon the addition of the first dye, a major change (63%) in microbial diversity was observed; however, subsequent addition of other dyes did not affect the community profile significantly. Actinobacteria, Aquamicrobium, Mesorhizobium, Ochrobactrum, Thauera, Paracoccus, Achromobacter and Chelatacoccus affiliated phylotypes were the major phylotypes detected. Our results demonstrate that microbial fuel cells could be a promising alternative for treatment of textile wastewaters and an active bacterial community can rapidly be established for simultaneous azo dye decolorization and sustainable electricity generation.

  17. Polarization-independent holographic gratings based on azo-dye-doped polymer-dispersed liquid-crystal films.

    PubMed

    Fuh, Andy Ying-Guey; Chen, Che-Chang; Cheng, Ko-Ting; Liu, Cheng-Kai; Chen, Wei-Ko

    2010-01-10

    We demonstrate polarization-independent holographic gratings (PIHGs) based on azo-dye-doped polymer-dispersed liquid crystal films. The PIHGs are recorded by irradiation under an intensity-modulated interference field, generated by two linearly polarized green optical beams, and by simultaneously applying a suitable AC voltage to the sample. The photoexcited azo dyes are adsorbed onto the UV-cured polymer film with their long axes parallel to the normal of the substrate. When the applied voltage is switched off, the PIHGs are generated with periodic modulation of liquid-crystal structures with transparently homeotropic and randomly scattered alignments. Additionally, the generated PIHGs can be completely switched off by an applied voltage.

  18. Enhanced degradation of azo dye by a stacked microbial fuel cell-biofilm electrode reactor coupled system.

    PubMed

    Cao, Xian; Wang, Hui; Li, Xiao-Qi; Fang, Zhou; Li, Xian-Ning

    2017-03-01

    In this study, a microbial fuel cell (MFC)-biofilm electrode reactor (BER) coupled system was established for degradation of the azo dye Reactive Brilliant Red X-3B. In this system, electrical energy generated by the MFC degrades the azo dye in the BER without the need for an external power supply, and the effluent from the BER was used as the inflow for the MFC, with further degradation. The results indicated that the X-3B removal efficiency was 29.87% higher using this coupled system than in a control group. Moreover, a method was developed to prevent voltage reversal in stacked MFCs. Current was the key factor influencing removal efficiency in the BER. The X-3B degradation pathway and the types and transfer processes of intermediate products were further explored in our system coupled with gas chromatography-mass spectrometry.

  19. Optically controllable and focus-tunable Fresnel lens in azo-dye-doped liquid crystals using a Sagnac interferometer.

    PubMed

    Yeh, Hui-Chen; Kuo, Yi-Chieh; Lin, Shih-Hung; Lin, Jia-De; Mo, Ting-Shan; Huang, Shuan-Yu

    2011-04-15

    This study demonstrates a tunable Fresnel lens in an azo-dye-doped liquid crystal (ADDLC) film using an interference technique. One Fresnel-patterned green beam using a Sagnac interferometer irradiated the UV-illuminated ADDLC cell, yielding a concentric zone plate distribution with homeotropic and isotropic structures in bright and dark regions of the green interference pattern. The proposed Fresnel lens is polarization independent, focus tunable, and the focusing efficiency of the device can be optically controlled.

  20. Effect of unmodulated laser light on the nanostructure of a thin solid AD-1 azo dye film

    SciTech Connect

    Dubrovkin, A M; Ezhov, A A; Kozenkov, V M; Magnitskiy, Sergey A; Nagorskiy, Nikolay M; Panov, Vladimir I

    2010-06-23

    Exposure to light uniform in intensity and polarisation causes marked changes in the surface topography of a thin (320 nm) nanostructured AD-1 low molecular weight azo dye film. Linearly polarised incoherent light with a wavelength of 470 nm and intensity of 1 mW cm{sup -2} produces numerous teardrop-shaped hillocks of the order of 200 nm in radius over most of the film surface. (letters)

  1. Accelerated decolorization of azo dye Congo red in a combined bioanode-biocathode bioelectrochemical system with modified electrodes deployment.

    PubMed

    Kong, Fanying; Wang, Aijie; Cheng, Haoyi; Liang, Bin

    2014-01-01

    In this study, BES with bioanode and biocathode was applied to decolorize an azo dye Congo red (CR). Results showed that the Congo red decolorization efficiency (CR-DE) within 23 h in a combined bioanode-biocathode single chamber BES was 98.3±1.3%, significantly higher than that of mixed solution in a dual chamber BES (67.2±3.5%) (P<0.005). Various electrodes deployments (horizontal, vertical and surrounding) in the combined bioanode-biocathode BES were further compared based on the decolorization performance and electrochemical characterization. Results indicated that CR-DE within 11h improved from 87.4±1.3% to 97.5±2.3%, meanwhile the internal resistance decreased from 236.6 to 42.2Ω as modifying the horizontal deployment to be a surrounding deployment. It proved that the combination of bioanode and biocathode with suitable electrodes deployment could accelerate the decolorization of azo dye Congo red, which would be great potential for the application of bioelectrochemical technology in azo dye wastewater treatment.

  2. Nonlinear optical performance of poled liquid crystalline azo-dyes confined in SiO2 sonogel films

    NASA Astrophysics Data System (ADS)

    Torres-Zúñiga, V.; Morales-Saavedra, O. G.; Rivera, E.; Flores-Flores, J. O.; Bañuelos, J. G.; Ortega-Martínez, R.

    2010-01-01

    The catalyst-free sonogel route was implemented to fabricate highly pure, optically active, hybrid azo-dye/SiO2-based spin-coated thin films deposited onto ITO-covered glass substrates. The implemented azo-dyes exhibit a push-pull structure; thus chromophore electrical poling was performed in order to explore their quadratic nonlinear optical (NLO) performance and the role of the SiO2 matrix for allowing molecular alignment within the sonogel host network. Morphological and optical characterizations were performed to the film samples according to atomic force microscopy (AFM), ultraviolet-visible (UV-Vis) spectroscopy and the Maker-fringe technique. Regardless of absence of a high glass transition temperature (T g) in the studied monomeric liquid crystalline azo-dyes, some hybrid films displayed stable NLO activity such as second harmonic generation (SHG). Results show that the chromophores were homogeneously embedded within the SiO2 sonogel network, where the guest-host molecular and mechanical interactions permitted a stable monomeric electrical alignment in this kind of environment.

  3. Steady performance of a zero valent iron packed anaerobic reactor for azo dye wastewater treatment under variable influent quality.

    PubMed

    Zhang, Yaobin; Liu, Yiwen; Jing, Yanwen; Zhao, Zhiqiang; Quan, Xie

    2012-01-01

    Zero valent iron (ZVI) is expected to help create an enhanced anaerobic environment that might improve the performance of anaerobic treatment. Based on this idea, a novel ZVI packed upflow anaerobic sludge blanket (ZVI-UASB) reactor was developed to treat azo dye wastewater with variable influent quality. The results showed that the reactor was less influenced by increases of Reactive Brilliant Red X-3B concentration from 50 to 1000 mg/L and chemical oxygen demand (COD) from 1000 to 7000 mg/L in the feed than a reference UASB reactor without the ZVI. The ZVI decreased oxidation-reduction potential in the reactor by about 80 mV. Iron ion dissolution from the ZVI could buffer acidity in the reactor, the amount of which was related to the COD concentration. Fluorescence in situ hybridization test showed the abundance of methanogens in the sludge of the ZVI-UASB reactor was significantly greater than that of the reference one. Denaturing gradient gel electrophoresis showed that the ZVI increased the diversity of microbial strains responsible for high efficiency.

  4. Decolourization of the azo dye Orange G in aqueous solution via a heterogeneous Fenton-like reaction catalysed by goethite.

    PubMed

    Wu, Honghai; Dou, Xiaowen; Deng, Dayi; Guan, Yufeng; Zhang, Liguo; He, Guangping

    2012-01-01

    Decolourization of the azo dye Orange G (OG) was investigated by using goethite/H2O2 as a heterogeneous Fenton-like reagent. Five principle operational parameters, namely pH, ion strength, concentrations ofgoethite (alpha-FeOOH) and hydrogen peroxide (H2O2), and reaction temperature, were taken into account to investigate how these controlling factors mediated OG decolourization. Goethite surfaces catalysed a Fenton-like reaction responsible for decolourizing OG following pseudo-first-order kinetics (R2 > 0.964). This process was effective but seriously impacted by the medium pH and the dosages of both alpha-FeOOH and H2O2. The decolourization efficiencies of OG increased with the decrease of solution pH and NaCl (chloride ion) concentration and/or the increase of H2O2. The acidic aqueous medium conditions were likely favourable due to the surface adsorption of the negatively charged OG leading to the promotion of decolourizing OG. The apparent activation energy (E) for this reaction was 42.18 kJ mol(-1), a relatively low value. This is consistent with the OG decolourization being enhanced with the reaction temperature increase.

  5. Study on the inclusion complexes of cyclodextrin and sulphonated azo dyes by electrospray ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Zhang, Huarong; Chen, Gang; Wang, Ling; Ding, Lan; Tian, Yuan; Jin, Weiqun; Zhang, Hanqi

    2006-05-01

    The inclusion complexes of [alpha]-, [beta]-cyclodextrin ([alpha]-, [beta]-CD) and sulphonated azo dyes ligands (Orange II, Ponceau SX, Allura red AC and Tartrazine) were studied by electrospray ionization mass spectrometry (ESI-MS) and the dissociation constants (KD) of the inclusion complexes were determined. A new method to obtain the dissociation constants of CD-ligand inclusion complexes without curve fitting was developed. Once the total concentrations of CD and ligand have been known, KD can be calculated from the sum peak intensities of free CD and inclusion complex and the number of binding site can be obtained from the mass spectrum. Ponceau SX, Allura red AC and Tartrazine binding to [alpha]-CD form 1:1 inclusion complexes with KD values of 1.33 × 10-5 mol L-1, 4.85 × 10-6 mol L-1 and 7.47 × 10-5 mol L-1, respectively. The obtained KD values of the inclusion complexes of above-mentioned three sulphonated azo dyes ligands binding to [beta]-CD in turn are 3.93 × 10-6 mol L-1, 6.50 × 10-6 mol L-1 and 1.12 × 10-4 mol L-1, respectively. The 1:1 and 1:2 inclusion complexes are found in the systems of CD and Orange II. KD,1 and KD,2 of [alpha]-CD and Orange II inclusion complexes are 4.05 × 10-4 mol L-1 and 4.60 × 10-7 (mol L-1)2, respectively. 3.94 × 10-5 mol L-1 and 1.72 × 10-7 (mol L-1)2 are the KD,1 and KD,2 of [beta]-CD and Orange II inclusion complexes, respectively. The competition experiments were performed to validate the results obtained by one ligand. According to the proposed method, the KD values of inclusion complexes regardless of any stoichiometric relation of host and guest can be obtained.

  6. Colour removal from aqueous solutions of metal-complex azo dyes using bacterial cells of Shewanella strain J18 143.

    PubMed

    Li, Tie; Guthrie, James Thomas

    2010-06-01

    The decoloration treatment of textile dye effluents through biodegradation, using bacterial cells, has been studied as a possible means of solving some of the problems that are associated with the pollution of water sources by colorants. In this paper, the use of whole bacterial cells of Shewanella J18 143 for the reduction of aqueous solutions of selected mono-azo, metal-complex dyes, namely Irgalan Grey GLN, Irgalan Black RBLN and Irgalan Blue 3GL, was investigated. The effects of temperature, pH and dye concentration on colour removal were also investigated and shown to be important. The operative conditions for the removal of colour were 30 degrees C, at pH 6.8, with a final dye concentration of 0.12 g/L in the colour reduction system. This study provides an extension to the application of Shewanella strain J18 143 bacterial cells in the decoloration of textile wastewaters.

  7. Effect of additives in photocatalytic degradation of commercial azo dye Lanaset Sun Yellow 180.

    PubMed

    Araña, J; Zerbani, D; Herrera Melián, J A; Garzón Sousa, D; González Díaz, O; Doña Rodríguez, J M

    2013-04-01

    The photocatalytic degradation of the commercial dye Lanaset Sun Yellow 180 was studied in the presence and absence of the different additives used in the dye's formulation. The experiments were performed with Degussa P25 as received and doped with Fe (Fe-TiO2) and a new catalyst synthesized by our research group (ECT-1023). The best efficiency was achieved with Fe-TiO2. With this catalyst, the formation of a photoactive complex was observed between the dye and Fe atoms of the catalyst surface that accelerated degradation. FTIR studies revealed that the complex was formed by interaction between the dye's carbonyl groups and the atoms of the metal. In mixtures of the dye containing citric acid or acetate, degradation was notably inhibited with the catalysts Fe-TiO2 and ECT-1023 because of the formation of carboxylates on their surface. This inhibitory effect was neutralized when all the additives were present in the solution. Toxicity analyses indicated that intermediates were not toxic. Thus, the photocatalytic methods seem to be optimal for the decolourization of wastewaters containing this dye.

  8. Genotoxic and carcinogenic products arising from reductive transformations of the azo dye, Disperse Yellow 7.

    PubMed

    Balakrishnan, Vimal K; Shirin, Salma; Aman, Ahmed M; de Solla, Shane R; Mathieu-Denoncourt, Justine; Langlois, Valerie S

    2016-03-01

    Selected aromatic azo and benzidine based dyes are priority compounds under the Government of Canada's Chemical Management Plan (CMP) for environmental risk assessments. Organic compounds undergo chemical and biological transformations when they interact with environmental matrices and biotic species; identifying the transformation products is thus a critical component of the risk assessment process. Here, we used zero valent iron (ZVI) to initiate the reduction of the diazo compound dye Disperse Yellow 7 (DY 7). Using state-of-the-art accurate mass Liquid Chromatography-Quadrupole Time of Flight-Mass Spectroscopy (LC-QToF-MS), four transformation products were conclusively identified, while a fifth product was tentatively ascertained. The conclusively established transformation products included p-phenylenediamine (p-PDA, a known genotoxin), 4-aminoazobenzene (4-AAB, a category 2 carcinogen) and 4-aminobiphenyl (4-ABP, a category 1 human carcinogen). 4-ABP is thought to form via a benzidine rearrangement; this is the first report of DY 7 undergoing a benzidine rearrangement. Given the importance of reduction processes in the metabolism of organic contaminants by aquatic species, we used LC-MS/MS to analyze sediment samples that had been generated previously upon exposure of Western clawed frogs (Silurana tropicalis) to DY 7 (at exposure levels where cellular stress was observed in S. tropicalis). We found p-PDA, 4-AAB, and 4-ABP were present in all exposures, but not in any of the sediment controls, demonstrating that upon release of DY 7 to the aquatic environment, sediment dwelling organisms will metabolize DY 7 to generate known (and suspected) human carcinogens, including through a previously unreported in vivo benzidine rearrangement to produce 4-ABP.

  9. Adsorption of an anionic azo dye by cross-linked chitosan/bentonite composite.

    PubMed

    Liu, Qian; Yang, Bingchao; Zhang, Lujie; Huang, Ruihua

    2015-01-01

    In this study, cross-linked chitosan (CCS)/bentonite (BT) composite was prepared by the intercalation of chitosan in bentonite and the cross-linking reaction between chitosan and glutaraldehyde. CCS/BT composite was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal gravimetric analyses (TGA). Their adsorption characteristics were assessed by using an azo dye (Amido Black 10B) as a model adsorbate. The adsorption of Amido Black 10B onto the CCS/BT composite was found to be optimal at pH 2. The adsorption isotherm was well described by the Langmuir model and the maximum adsorption capacity was 323.6 mg/g at 293K and pH 2. Amido Black 10B adsorption kinetics followed a pseudo-second-order kinetic model. The calculated thermodynamic parameters showed that the adsorption of Amido Black 10B by CCS/BT composite was spontaneous and endothermic in nature.

  10. Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

    PubMed

    Kurtan, U; Amir, Md; Baykal, A; Sözeri, H; Toprak, M S

    2016-03-01

    Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water.

  11. A comparison of different activated carbon performances on catalytic ozonation of a model azo reactive dye.

    PubMed

    Gül, S; Eren, O; Kır, S; Onal, Y

    2012-01-01

    The objective of this study is to compare the performances of catalytic ozonation processes of two activated carbons prepared from olive stone (ACOS) and apricot stone (ACAS) with commercial ones (granular activated carbon-GAC and powder activated carbon-PAC) in degradation of reactive azo dye (Reactive Red 195). The optimum conditions (solution pH and amount of catalyst) were investigated by using absorbencies at 532, 220 and 280 nm wavelengths. Pore properties of the activated carbon (AC) such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N(2) adsorption. The highest BET surface area carbon (1,275 m(2)/g) was obtained from ACOS with a particle size of 2.29 nm. After 2 min of catalytic ozonation, decolorization performances of ACOS and ACAS (90.4 and 91.3%, respectively) were better than that of GAC and PAC (84.6 and 81.2%, respectively). Experimental results showed that production of porous ACs with high surface area from olive and apricot stones is feasible in Turkey.

  12. Deciphering effects of functional groups and electron density on azo dyes degradation by graphene loaded TiO2

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Liang, Xiao; Chen, Bor-Yann; Chang, Chang-Tang

    2015-12-01

    This study tended to decipher the mechanism of photo degradation of azo dyes, which bond was favorable to be broken for application of wastewater decolorization. That is, from chemical structure perspective, the critical substituents to affect electron donor/acceptor for dye degradation would be identified in this research. The model reactive blacks (RB5), reactive blue 171 (RB171) and reactive red 198 (RR198) were degraded by graphene loaded TiO2, indicating how the electron withdrawing and releasing groups affect azo dye degradability. The byproducts and intermediate products were analyzed by ultraviolet-visible spectroscopy (UV-vis), gas chromatography-mass spectrometry (GC-MS) and ion chromatography (IC). Furthermore, the radicals involved in the reaction were found by electron paramagnetic resonance (ESR) to confirm the main oxidized species of hydroxyl radicals rather than the light generated positive holes. The finding revealed that the breakages of the bonds were due to the electron density changes around the bonds. This principle can be applicable not only for RB5 degradation, but also for reactive blue 171 (RB171), reactive red 198 (RR198) and some other textile dyes.

  13. Microaerophilic Symmetric Reductive Cleavage of Reactive Azo Dye-Remazole Brilliant Violet 5R by Consortium VIE6: Community Synergism.

    PubMed

    Shah, Binal; Jain, Kunal; Jiyani, Hardik; Mohan, Venkata; Madamwar, Datta

    2016-11-01

    The textile-dyeing industry is rated as one of the foremost industrial sectors that explodes large amount of pollutants to the environment. Reactive azo dye degradation, being a major constituent of these pollutants and perilous material, has been constantly receiving scientific attention. In textile industry, use of Remazole Brilliant Violet 5R (RBV5R) as reactive azo dyes is more frequent. Highly competent, RBV5R-degrading bacterial consortium VIE6 was developed from the soil of the Vatva Industrial Estate, Gujarat, India. Consortium VIE6 comprised of five bacterial strains Bacillus sp. DMB1, Staphylococcus sp. DMB2, Escherichia sp. DMB3, Enterococcus sp. DMB4, and Pseudomonas sp. DMB5. These strains convened a better decolorization efficiency between 200 and 1000 mg/L of dye concentration and were much stable at pH 6.5, 37 °C. Azoreductase, laccase, and lignin peroxidase activities of consortium showed significant variation throughout the degradation process indicating the different metabolic capabilities of the existing microflora. The community interactions and synergism were shown to facilitate the biotransformation of RBV5R by combination of various electron donors. Voltammograms revealed the variations in electron discharge properties which coincide with the dynamics of community derived using qPCR assays. The variation in catabolic capabilities of the individual strains was observed during active metabolism of RBV5R degradation pertaining to the aerobic and facultative functions.

  14. The testing of several biological and chemical coupled treatments for Cibacron Red FN-R azo dye removal.

    PubMed

    García-Montaño, Julia; Domènech, Xavier; García-Hortal, José A; Torrades, Francesc; Peral, José

    2008-06-15

    Several biological and chemical coupled treatments for Cibacron Red FN-R reactive azo dye degradation have been evaluated. Initially, a two-stage anaerobic-aerobic biotreatment has been assessed for different dye concentrations (250, 1250 and 3135 mg l(-1)). 92-97% decolourisation was attained during the anaerobic digestion operating in batch mode. However, no dissolved organic carbon (DOC) removal neither biogas production was observed during the process, indicating that no methanogenesis occurred. Additionally, according to Biotox and Zahn-Wellens assays, the anaerobically generated colourless solutions (presumably containing the resulting aromatic amines from azo bond cleavage) were found to be more toxic than the initial dye as well as aerobically non-biodegradable, thus impeding the anaerobic-aerobic biological treatment. In a second part, the use of an advanced oxidation process (AOP) like photo-Fenton or ozonation as a chemical post-treatments of the anaerobic process has been considered for the complete dye by-products mineralisation. The best results were obtained by means of ozonation at pH 10.5, achieving a global 83% mineralisation and giving place to a final harmless effluent. On the contrary, the tested photo-Fenton conditions were not efficient enough to complete oxidation.

  15. Improved azo dye decolorization in an advanced integrated system of bioelectrochemical module with surrounding electrode deployment and anaerobic sludge reactor.

    PubMed

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2015-01-01

    A new integrated system, embedding a modular bioelectrochemical system (BES) with surrounding electrode deployment into an anaerobic sludge reactor (ASR), was developed to improve azo dye decolorization. Results demonstrated that the AO7 decolorization and COD removal can be improved without co-substrate in such system. The kinetic rate of decolorization (0.54h(-1)) in integrated system was 1.4-fold and 54.0-fold higher than that in biocathode BES (0.39h(-1)) and ASR (0.01h(-1)), respectively. COD can be removed after cleavage of azo bond, different from biocathode BES. The combined advantages of this integrated system were achieved by the cooperation of biocathode in modular BES and sludge in ASR. Biocathode was a predominant factor in AO7 decolorization, and anaerobic sludge contributed negligibly to AO7 reduction decolorization but mostly in the COD removal. These results demonstrated the great potential of integrating a BES module with anaerobic treatment process for azo dye treatment.

  16. Can nitro groups really anchor onto TiO2? Case study of dye-to-TiO2 adsorption using azo dyes with NO2 substituents.

    PubMed

    Zhang, Lei; Cole, Jacqueline M

    2016-07-28

    The nitro group has recently been suggested as a new type of anchor for dye-sensitized solar cells (DSSCs) and has shown promising optoelectronic properties. Considering the excellent electron withdrawing ability of the nitro group and wider materials selection brought about by this substituent, it is helpful to evaluate the interfacial structures and photophysics of more organic dyes where NO2 poses as the dye-to-TiO2 anchor. A computational study on a family of azo dyes bearing a nitro group is presented, where the effect of certain side groups on their optical properties is examined. Both isolated dye molecules and dye/TiO2 nanocomposites are studied via density functional theory and time-dependent density functional theory, with complementary experimental UV/vis absorption spectroscopy and photovoltaic device testing. Results demonstrate that these nitro-containing dyes prefer a monodentate anchoring mode on a TiO2 cluster. These nitro dyes reveal weak, but non-negligible, adsorption onto TiO2; yet, very low photovoltaic performance once incorporated into a DSSC device. This poor delivery of nitro groups as DSSC anchors is ostensibly inconsistent with previous findings; but is rationalized via the "auxiliary anchor" concept.

  17. Degradation process analysis of the azo dyes by catalytic wet air oxidation with catalyst CuO/γ-Al2O3.

    PubMed

    Hua, Li; Ma, Hongrui; Zhang, Lei

    2013-01-01

    Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide.

  18. The role of Aster amellus Linn. in the degradation of a sulfonated azo dye Remazol Red: a phytoremediation strategy.

    PubMed

    Khandare, Rahul V; Kabra, Akhil N; Tamboli, Dhawal P; Govindwar, Sanjay P

    2011-02-01

    Phytoremediation is a novel and promising approach for the treatment of pollutants. This study did explore the potential of Aster amellus Linn. to decolorize a sulfonated azo dye Remazol Red (RR), a mixture of dyes and a textile effluent. Induction in the activities of lignin peroxidase, tyrosinase, veratryl alcohol oxidase and riboflavin reductase was observed during RR decolorization, suggesting their involvement in the metabolism of RR. UV-Visible absorption spectrum, HPLC and FTIR analysis confirmed the degradation of RR. Four metabolites after the degradation of the dye were identified as 2-[(3-diazenylphenyl) sulfonyl] ethanesulfonate, 4-amino-5-hydroxynaphthalene-2,7-disulfonate, naphthalene-2-sulfonate and 3-(1,3,5-triazin-2-ylamino)benzenesulfonate by using GC/MS. Textile effluent and mixture of dyes showed 47% and 62% decrease respectively in American Dye Manufacturers Institute value. BOD of textile effluent and mixture of dyes were reduced by 75% and 48% respectively, COD of industrial effluent and mixture of dyes was reduced by 60% and 75% and TOC was reduced by 54% and 69% respectively after the treatment by A. amellus for 60 h; this indicated that the plant can be used for cleaning textile effluents. Toxicity study revealed the phytotransformation of RR into non-toxic products.

  19. Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives, amaranth and bismarck brown in aqueous suspension.

    PubMed

    Tariq, M Abu; Faisal, M; Muneer, M

    2005-12-09

    Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives such as amaranth (1) and bismarck brown (2) has been investigated in aqueous suspension by monitoring the change in substrate concentration employing UV spectroscopic analysis technique as a function of irradiation time. The degradation was studied under different conditions such as types of TiO(2), pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H(2)O(2)), potassium bromate (KBrO(3)) and ammonium persulphate (NH(4))(2)S(2)O(8) besides air. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 showed comparatively highest photocatalytic activity. The dye derivative, bismarck brown (2) was found to degrade faster than amaranth dye (1).

  20. Novel bio-electro-Fenton technology for azo dye wastewater treatment using microbial reverse-electrodialysis electrolysis cell.

    PubMed

    Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

    2017-03-01

    Development of sustainable technologies for treatment of azo dyes containing wastewaters has long been of great interest. In this study, we proposed an innovative concept of using microbial reverse-electrodialysis electrolysis cell (MREC) based Fenton process to treat azo dye wastewater. In such MREC-Fenton integrated process, the production of H2O2 which is the key reactant of fenton-reaction was driven by the electrons harvested from the exoelectrogens and salinity-gradient between sea water and fresh water in MREC. Complete decolorization and mineralization of 400mgL(-1) Orange G was achieved with apparent first order rate constants of 1.15±0.06 and 0.26±0.03h(-1), respectively. Furthermore, the initial concentration of orange G, initial solution pH, catholyte concentration, high and low concentration salt water flow rate and air flow rate were all found to significantly affect the dye degradation. This study provides an efficient and cost-effective system for the degradation of non-biodegradable pollutants.

  1. Decolorization and biogas production by an anaerobic consortium: effect of different azo dyes and quinoid redox mediators.

    PubMed

    Alvarez, L H; Valdez-Espinoza, R; García-Reyes, R B; Olivo-Alanis, D; Garza-González, M T; Meza-Escalante, E R; Gortáres-Moroyoqui, P

    2015-01-01

    The inhibitory effect of azo dyes and quinoid compounds on an anaerobic consortium was evaluated during a decolorization process and biogas production. In addition, the impact of quinoid compounds such as lawsone (LAW) and anthraquinone-2,6-disulfonate (AQDS) on the rate of decolorization of Direct Blue 71 (DB71) was assessed. The anaerobic consortium was not completely inhibited under all tested dye concentrations (0.1-2 mmol l(-1)), evidenced by an active decolorization process and biogas production. The presence of quinoid compounds at different concentrations (4, 8, and 12 mmol l(-1)) also inhibited biogas production compared to the control incubated without the quinoid compounds. In summary, the anaerobic consortium was affected to a greater extent by increasing the quantity of azo dyes or quinoid compounds. Nevertheless, at a lower concentration (1 mmol l(-1)) of quinoid compounds, the anaerobic consortium effectively decolorized 2 mmol l(-1) of DB71, increasing up to 5.2- and 20.4-fold the rate of decolorization with AQDS and LAW, respectively, compared to the control lacking quinoid compounds.

  2. Degradation of azo dye methyl red by alkaliphilic, halotolerant Nesterenkonia lacusekhoensis EMLA3: application in alkaline and salt-rich dyeing effluent treatment.

    PubMed

    Bhattacharya, Amrik; Goyal, Nidhi; Gupta, Anshu

    2017-03-02

    Effluents from textile industries are highly colored due to vast use of various azo dyes and color is the first visual indicator of pollution. Biological treatment of textile effluent is often hampered due to the alkaline pH and high salinity; a common characteristic of many textile industrial wastewaters. Considering this, the present study explores the potential of a newly isolated halotolerant and alkaliphilic bacterium Nesterenkonia lacusekhoensis EMLA3 for degradation of methyl red (MR) dye under alkaline condition. Strain EMLA3 showed 97% degradation of 50 mg L(-1) MR after 16 h at initial pH of 11.5 in nutrient medium. Dye degradation by the isolate is supported by the formation of low-molecular weight metabolites as divulge through GC-MS & FTIR studies Optimum dye degradation was observed in the pH range of 8.0-11.5 and temperature range of 30-35 °C. Significant MR degrading activity of the strain could be achieved in the presence of very high salt level (100-120 g L(-1) NaCl) and in co-presence of different heavy metals. Application of strain to alkaline pH, salt, and heavy metals laden-textile effluent resulted in overall 83% dye removal from the effluent after 120 h of treatment under static condition. Furthermore, the property of microbe to drop-down the pH of wastewater from 11.5 to 8.60 after treatment also lowers the need of additional neutralization treatment. The entire study thus comes out with novel application of N. lacusekhoensis-a less explored extremophilic bacterium-for treatment of alkaline and salt-rich azo dye-containing wastewaters.

  3. Photocatalytic degradation of an azo-dye on TiO2/activated carbon composite material.

    PubMed

    Andriantsiferana, C; Mohamed, E F; Delmas, H

    2014-01-01

    A sequential adsorption/photocatalytic regeneration process to remove tartrazine, an azo-dye in aqueous solution, has been investigated. The aim ofthis work was to compare the effectiveness of an adsorbent/photocatalyst composite-TiO2 deposited onto activated carbon (AC) - and a simple mixture of powders of TiO2 and AC in same proportion. The composite was an innovative material as the photocatalyst, TiO2, was deposited on the porous surface ofa microporous-AC using metal-organic chemical vapour deposition in fluidized bed. The sequential process was composed of two-batch step cycles: every cycle alternated a step of adsorption and a step of photocatalytic oxidation under ultra-violet (365 nm), at 25 degreeC and atmospheric pressure. Both steps, adsorption and photocatalytic oxidation, have been investigated during four cycles. For both materials, the cumulated amounts adsorbed during four cycles corresponded to nearly twice the maximum adsorption capacities qmax proving the photocatalytic oxidation to regenerate the adsorbent. Concerning photocatalytic oxidation, the degree of mineralization was higher with the TiO2/AC composite: for each cycle, the value of the total organic carbon removal was 25% higher than that obtained with the mixture powder. These better photocatalytic performances involved better regeneration than higher adsorbed amounts for cycles 2, 3 and 4. Better performances with this promising material - TiO2 deposited onto AC - compared with TiO2 powder could be explained by the vicinity of photocatalytic and AC adsorption sites.

  4. Spectroscopic and semiempirical studies of the phototropic species of 8-amino-5,8'-azo-bis-naphthalene-2-sulphonic acid

    NASA Astrophysics Data System (ADS)

    Wojciechowska, Monika; Wojciechowski, Grzegorz; Wasiak, Wiesław

    2003-09-01

    Structural study of the azo compound obtained as a result of diazotization and coupling of 8-amino-naphthalene-2-sulfonic acid (Cleve's acid), has been performed by the spectroscopic methods 1H NMR and FTIR. UV-vis spectra of 8-amino-5,8'-azo-bis-naphthalene-2-sulphonic acid (CA-CA) were measured in water environment at different pH values and at a constant ionic strength. On the basis of the NMR, FTIR as well as on the grounds of a comparison of the experimental UV-vis spectra with those obtained by the MM/ PM5 in water followed by ZINDO method calculation, geometry of the CA-CA molecule in water solution has been proposed. Moreover, the value of the first dissociation constant of the dye has been determined (2.75×10 -2).

  5. New 1,2,4-triazole-based azo-azomethine dyes. Part II: synthesis, characterization, electrochemical properties and computational studies.

    PubMed

    Khanmohammadi, Hamid; Erfantalab, Malihe; Bayat, Atena; Babaei, Ali; Sohrabi, Masoud

    2012-11-01

    A new series of monoiminated 1,2,4-triazole-based azo-azomethine dyes have been synthesized via condensation reaction of 4-amino-3-methyl-5-mercapto-1,2,4-triazole with various substituted azo-coupled salicylaldehyde. The dyes have been characterized by using FT-IR, UV-Vis and (1)H NMR spectroscopic methods as well as elemental analysis. The electrochemical behavior of the dyes has been investigated by cyclic voltammetry in DMSO at five different scan rates. Solvatochromic behavior of the dyes has been also investigated in four organic solvents with different polarities. Furthermore, the (1)H chemical shielding of the dyes were studied by the gauge independent atomic orbital (GIAO) method at the level of density functional theory (DFT).

  6. Solvatochromism, spectral properties and antimicrobial activities of new azo-azomethine dyes with N2S2O2 donor set of atoms

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Hamid; Pass, Maryam; Rezaeian, Khatereh; Talei, Gholamreza

    2014-08-01

    Six new azo-azomethine dyes, H2Ln (n = 1-6), with N2S2O2 donor set of atoms have been prepared via condensation reaction of 1,10-diaza-4,7-dithiadecane, I, with substituted azo-coupled salicylaldehyde. The dyes were characterized by IR, UV-Vis and 1H NMR spectroscopic methods as well as elemental analysis. The solvatochromic behavior of the dyes was also probed by studying their UV-Vis spectra in four pure organic solvents of different polarities and a meaningful correlation was observed. Furthermore, all prepared dyes were assayed for their antibacterial and antifungal activities by disc diffusion method. The results indicated that all prepared dyes show good inhibition against Staphylococcus epidermidis and Bacillus cereus and did not show any antibacterial activity against Escherichia coli as compared to standard drugs.

  7. Development of a solid phase microextraction method for detection of the use of banned azo dyes in coloured textiles and leather

    PubMed

    Cioni; Bartolucci; Pieraccini; Meloni; Moneti

    1999-01-01

    A new method to detect the use of banned azo dyes in the manufacture and treatment of coloured textiles and leather is described. The determination of the azo dyes was made by quantification of aromatic amines generated by reductive cleavage in a citrate buffer medium. The aromatic amines were then extracted from 1 mL of the reaction solution by means of solid phase microextraction (SPME) and determined by gas chromatography/mass spectrometry (GC/MS). We also evaluate accuracy, precision, range of linearity and limit of detection for the eighteen aromatic amines investigated, and show that the method is comparable with current established methods. Copyright 1999 John Wiley & Sons, Ltd.

  8. Binding of reactive brilliant red to human serum albumin: insights into the molecular toxicity of sulfonic azo dyes.

    PubMed

    Li, W Y; Chen, F F; Wang, Shi-Long

    2010-05-01

    The non-covalent interaction of reactive brilliant red (RBR) as a representative of sulfonic azo compounds with human serum albumin (HSA) was investigated by a combination of UV-VIS spectrometry, fluorophotometry, circular dichroism (CD) and isothermal titration calorimetry (ITC) technique. The thermodynamic characterization of the interaction was performed. The saturation binding numbers of RBR on peptide chains were determined and the effects of electrolytes and temperature were investigated. The ionic interaction induced a combination of multiple non-covalent bonds including hydrogen bonds, hydrophobic interactions and van der Waals force. A three-step binding model of RBR was revealed. The binding of RBR molecules might occur on the external surface of HSA via electric interaction when the mole ratio of RBR to HSA was less than 40 and RBR molecules entered the hydrophobic intracavity of HSA when ratio was more than 40. Moreover, RBR binding resulted in a conformational change in the structure of HSA or even the precipitation of HSA and inhibited its function accordingly. The possible binding site and the conformational transition of HSA were hypothesized and illustrated. This work provides a new insight into non-covalent interactions between sulfonic azo compounds and proteins, which may be further used to investigate the potential toxicity mechanism of azo dyes.

  9. [Effects of veratryl alcohol and tween 80 on ligninase production and its roles in decolorization of azo dyes by white-rot basidiomycete PM2].

    PubMed

    Jia, Rong; Tang, Bi-Kui; Zhang, Xiao-Bin; He, Yue-Mei

    2004-03-01

    Basidiomycete PM2, a lignin-degrading white rot fungus, produces lgnin peroxidase (Lip) and manganese peroxidase (Mnp) in nutrient nitrogen limited liquid cultures. This fungus was selected for its ability to decolorize azo group of dyes. In order to improve production of the peroxidases and rapid dye decolorizing activity by basidiomycete PM2, the addition of veratryl alcohol or Tween 80 to nutrient nitrogen limited liquid cultures were tested. It was found to have a large stimulatory effect on Mnp activities and decolorization rate of azo dyes. A maximum Mnp activities of 254.2 u/L with veratryl alcohol and 192.2 u/L with Tween 80 were achieved respectively. These values were about 3.4-fold and 2.5-fold higher than that obtained in the control cultures (without alcohol or Tween 80), whereas the levels of Lip activity detected were very low (about 12 u/L)in all the cultures. In further experiments using three kinds of azo dyes of congo red, orange G and orange IV, enzyme activities and dye decolorization were investigated in the above-mentioned cultures. The results showed that Mnp activities and decolorization were notably higher than those obtained in the control cultures in the presence of azo dyes. Cultures supplemented with Tween 80 were more adequate for dye decolorization. The rates of the decolorization with Tween 80 of congo red (95.4%), orange G (98.5%) and orange IV (54.4%) after 24 hours of dye incubation were higher than that supplemented with veratryl alcohol. According to the results, Mnp activities secreted by basidiomycete PM2 play an essential role in the process of dye decolorization. Tween 80 was the main factor affecting the decolorization. The analysis of structure of the three kinds of azo dyes indicats that the extent of decolorization is affected by the dye molecular structure. The types and quantity of the substituted groups on the aromatic ring of azo dyes have effect on the percentage of biological decolorization.

  10. Induction of anoxic microenvironment in multi-phase metabolic shift strategy during periodic discontinuous batch mode operation enhances treatment of azo dye wastewater.

    PubMed

    Nagendranatha Reddy, C; Naresh Kumar, A; Annie Modestra, J; Venkata Mohan, S

    2014-08-01

    Variation in anoxic microenvironment (multi-phase (MP) metabolic shift strategy) during cycle operation of periodic discontinuous batch/sequencing batch (PDBR/SBR) mode operation showed enhanced degradation of recalcitrant azo dye (C.I. Acid Black 10B) at higher dye load (1250mg/l). The process performance was evaluated by varying anoxic phasing period during cycle operation. Before multiphase (BMP) operation with 2.1% of anoxic period showed color/COD removal efficiency of 41.9%/46.3%. Increment in anoxic period responded favorable in enhancing treatment efficiency [AMPI (16.2%), 49.4%/52.4%; AMPII (26.6%), 54.7%/57.2%; AMPIII (34.9%), 58.4%/61.5%]. Relatively higher bio-electrochemical activity, persistent reductive behavior (redox catalytic currents, 0.26/-0.72μA), prevalence of redox shuttlers (Fe-S proteins, cytochromes, quinones) facilitating enhanced electron transfer by minimization of associated losses and higher enzyme activities were observed with induction of anoxic phase. Anoxic condition shifts system microenvironment between oxidation and reduction assisting reduction of dye to its intermediates followed by their mineralization.

  11. Decolorization and detoxification of sulfonated azo dye C.I. Remazol Red and textile effluent by isolated Lysinibacillus sp. RGS.

    PubMed

    Saratale, Rijuta G; Gandhi, Soniya S; Purankar, Madhavi V; Kurade, Mayur B; Govindwar, Sanjay P; Oh, Sang Eun; Saratale, Ganesh D

    2013-06-01

    A novel bacterium was isolated from the soil of Ichalkaranji textile industrial area. Through 16S rRNA sequence matching and morphological observation it was identified as Lysinibacillus sp. RGS. This strain has ability to decolorize various industrial dyes among which, it showed complete decolorization and degradation of toxic sulfonated azo dye C.I. Remazol Red (at 30°C, pH 7.0, under static condition) with higher chemical oxygen demand (COD) reduction (92%) within 6 h of incubation. Various parameters like agitation, pH, temperature and initial dye concentrations were optimized to develop faster decolorization process. The supplementation of cheap co-substrates (e.g., extracts of agricultural wastes) could enhance the decolorization performance of Lysinibacillus sp. RGS. Induction in oxidoreductive enzymes presumably indicates involvement of these enzymes in the decolorization/degradation process. Analytical studies of the extracted metabolites confirmed the significant degradation of Remazol Red into various metabolites. The phytotoxicity assay (with respect to plants Phaseolus mungo and Sorghum vulgare) revealed that the degradation of Remazol Red produced nontoxic metabolites. Finally Lysinibacillus sp. RGS was applied to decolorize mixture of dyes and actual industrial effluent showing 87% and 72% decolorization (in terms of decrease in ADMI value) with 69% and 62% COD reduction within 48 h and 96 h, respectively. The foregoing result increases the applicability of the strain for the treatment of industrial wastewaters containing dye pollutants.

  12. Decolorization and detoxification of Synozol red HF-6BN azo dye, by Aspergillus niger and Nigrospora sp.

    PubMed

    Ilyas, Sidra; Rehman, Abdul

    2013-01-01

    In the present investigation the fungi, Aspergillus niger and Nigrospora sp. were employed for decolorization of Synozol red HF-6BN. Decolorization study showed that Aspergillus niger and Nigrospora sp. were able to decolorize 88% and 96% Synozol red 6BN, respectively, in 24 days. It was also studied that 86% and 90% Synozol red containing of dye effluent was decolorized by Aspergillus niger and Nigrospora sp. after 28 days of incubation at room temperature. A fungal-based protein with relative molecular mass of 70 kDa was partially purified and examined for enzymatic characteristics. The enzyme exhibited highest activity at temperature ranging from 40-50°C and at pH=6.0. The enzyme activity was enhanced in the presence of metal cations. High performance liquid chromatography analysis confirmed that these fungal strains are capable to degrade Synozol red dye into metabolites. No zones of inhibition on agar plates and growth of Vigna radiata in the presence of dye extracted sample, indicated that the fungal degraded dye metabolites are nontoxic to beneficial micro-flora and plant growth. Aspergillus niger and Nigrospora sp. have promising potential in color removal from textile wastewater-containing azo dyes.

  13. Efficient azo dye decolorization in a continuous stirred tank reactor (CSTR) with built-in bioelectrochemical system.

    PubMed

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Cheng, Hao-Yi; Wang, Ai-Jie

    2016-10-01

    A continuous stirred tank reactor with built-in bioelectrochemical system (CSTR-BES) was developed for azo dye Alizarin Yellow R (AYR) containing wastewater treatment. The decolorization efficiency (DE) of the CSTR-BES was 97.04±0.06% for 7h with sludge concentration of 3000mg/L and initial AYR concentration of 100mg/L, which was superior to that of the sole CSTR mode (open circuit: 54.87±4.34%) and the sole BES mode (without sludge addition: 91.37±0.44%). The effects of sludge concentration and sodium acetate (NaAc) concentration on azo dye decolorization were investigated. The highest DE of CSTR-BES for 4h was 87.66±2.93% with sludge concentration of 12,000mg/L, NaAc concentration of 2000mg/L and initial AYR concentration of 100mg/L. The results in this study indicated that CSTR-BES could be a practical strategy for upgrading conventional anaerobic facilities against refractory wastewater treatment.

  14. CYP-450 isoenzymes catalyze the generation of hazardous aromatic amines after reaction with the azo dye Sudan III.

    PubMed

    Zanoni, Thalita Boldrin; Lizier, Thiago M; Assis, Marilda das Dores; Zanoni, Maria Valnice B; de Oliveira, Danielle Palma

    2013-07-01

    This work describes the mutagenic response of Sudan III, an adulterant food dye, using Salmonella typhimurium assay and the generation of hazardous aromatic amines after different oxidation methods of this azo dye. For that, we used metabolic activation by S9, catalytic oxidation by ironporphyrin and electrochemistry oxidation in order to simulate endogenous oxidation conditions. The oxidation reactions promoted discoloration from 65% to 95% of Sudan III at 1 × 10(-4)molL(-1) and generation of 7.6 × 10(-7)molL(-1) to 0.31 × 10(-4)molL(-1) of aniline, o-anisidine, 2-methoxi-5-methylaniline, 4-aminobiphenyl, 4,4'-oxydianiline; 4,4'-diaminodiphenylmethane and 2,6-dimethylaniline. The results were confirmed by LC-MS-MS experiments. We also correlate the mutagenic effects of Sudan III using S. typhimurium with the strain TA1535 in the presence of exogenous metabolic activation (S9) with the metabolization products of this compound. Our findings clearly indicate that aromatic amines are formed due to oxidative reactions that can be promoted by hepatic cells, after the ingestion of Sudan III. Considering that, the use of azo compounds as food dyestuffs should be carefully controlled.

  15. Synthesis, spectral characterization, molecular modeling and antimicrobial studies of tridentate azo-dye Schiff base metal complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.

    2015-03-01

    Nine mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pt(IV) complexes of azo-dye Schiff's base ligand were synthesized and determined by different physical techniques. All the nine metal complexes are reported using elemental analysis, molar conductance, magnetic susceptibility, IR, UV-Vis, thermal analysis and 1H NMR, 13C NMR, mass, SEM, TEM, EDX, XRD spectral studies. The molar conductance measurements of all the complexes in DMF solution correspond to non-electrolytic nature. All complexes were of the high-spin type and found to have six-coordinate octahedral geometry except the Cu(II) complex which was four coordinate, square planar. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. In molecular modeling the geometries of azo-dye Schiff base ligand HL and its metal (II/III/IV) complexes were fully optimized with respect to the energy using the 6-31G basis set. These ligand and its metal complexes have also been screened for their in vitro antimicrobial activities.

  16. Mineralization of reactive azo dyes present in simulated textile waste water using down flow microaerophilic fixed film bioreactor.

    PubMed

    Balapure, Kshama; Bhatt, Nikhil; Madamwar, Datta

    2015-01-01

    The present research emphasizes on degradation of azo dyes from simulated textile wastewater using down flow microaerophilic fixed film reactor. Degradation of simulated textile wastewater (COD 7200mg/L and dye concentration 300mg/L) was studied in a microaerophilic fixed film reactor using pumice stone as a support material under varying hydraulic retention time (HRT) and organic loading rate (OLR). The intense metabolic activity of the inoculated bacterial consortium in the reactor led to 97.5% COD reduction and 99.5% decolorization of simulated wastewater operated under OLR of 7.2kgCODm(3)/d and 24h of HRT. FTIR, (1)H NMR and GC-MS studies revealed the formation of lower molecular weight aliphatic compounds under 24h of HRT, leading to complete mineralization of simulated wastewater. The detection of oxido-reductive enzyme activities suggested the enzymatic reduction of azo bonds prior to mineralization. Toxicity studies indicated that microbial treatment favors detoxification of simulated wastewater.

  17. Evaluation of anaerobic sludge volume for improving azo dye decolorization in a hybrid anaerobic reactor with built-in bioelectrochemical system.

    PubMed

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Wang, Ai-Jie; Cheng, Hao-Yi

    2017-02-01

    A hybrid anaerobic reactor with built-in bioelectrochemical system (BES) has been verified for efficiently treating mixed azo dye wastewater, yet still facing many challenges, such as uncertain reactor construction and insufficient electron donors. In this study, an up-flow hybrid anaerobic reactor with built-in BES was developed for acid orange 7 (AO7) containing wastewater treatment. Cathode and real domestic wastewater both served as electron donor for driving azo dye decolorization. The decolorization efficiency (DE) of AO7 (200 mg/L) in the hybrid reactor was 80.34 ± 2.11% with volume ratio between anaerobic sludge and cathode (VRslu:cat) of 0.5:1 and hydraulic retention time (HRT) of 6 h, which was 15.79% higher than that in BES without sludge zone. DE was improved to 86.02 ± 1.49% with VRslu:cat increased to 1:1. Further increase in the VRslu:cat to 1.5:1 and 2:1, chemical oxygen demand (COD) removal efficiency was continuously improved to 28.78 ± 1.96 and 32.19 ± 0.62%, but there was no obvious DE elevation (slightly increased to 87.62 ± 2.50 and 90.13 ± 3.10%). BES presented efficient electron utilization, the electron usage ratios (EURs) in which fluctuated between 11.02 and 13.06 mol e(-)/mol AO7. It was less than half of that in sludge zone of 24.73-32.06 mol e(-)/mol AO7. The present work optimized the volume ratio between anaerobic sludge and cathode that would be meaningful for the practical application of this hybrid system.

  18. Creation of second-order nonlinear optical effects by photoisomerization of polar azo dyes in polymeric films: theoretical study of steady-state and transient properties

    NASA Astrophysics Data System (ADS)

    Sekkat, Zouheir; Knoll, Wolfgang

    1995-10-01

    It was shown recently that the application of a dc field across a polymer film containing polar azo dye chromophores at a temperature far below that of its glass transition leads to an appreciable polar order when the azo dyes undergo cis \\left-right-double-arrow trans isomerization. We present a detailed theoretical study of this phenomenon based on the enhanced mobility of the azo chromophores during the isomerization process. The equations representing this phenomenological theory are solved by recurrence relations of Legendre polynomials, and both the steady state and the dynamics are investigated. Analytical expressions are derived for the photoinduced polar order and its related anisotropy for both cis and trans molecular distributions.

  19. Identification of non-regulated aromatic amines of toxicological concern which can be cleaved from azo dyes used in clothing textiles.

    PubMed

    Brüschweiler, Beat J; Küng, Simon; Bürgi, Daniel; Muralt, Lorenz; Nyfeler, Erich

    2014-07-01

    Azo dyes in textiles may release aromatic amines after enzymatic cleavage by skin bacteria or after dermal absorption and metabolism in the human body. From the 896 azo dyes with known chemical structure in the available textile dyes database, 426 azo dyes (48%) can generate one or more of the 22 regulated aromatic amines in the European Union in Annex XVII of REACH. Another 470 azo dyes (52%) can be cleaved into exclusively non-regulated aromatic amines. In this study, a search for publicly available toxicity data on non-regulated aromatic amines was performed. For a considerable percentage of non-regulated aromatic amines, the toxicity database was found to be insufficient or non-existent. 62 non-regulated aromatic amines with available toxicity data were prioritized by expert judgment with objective criteria according to their potential for carcinogenicity, genotoxicity, and/or skin sensitization. To investigate the occurrence of azo dye cleavage products, 153 random samples of clothing textiles were taken from Swiss retail outlets and analyzed for 22 high priority non-regulated aromatic amines of toxicological concern. Eight of these 22 non-regulated aromatic amines of concern could be detected in 17% of the textile samples. In 9% of the samples, one or more of the aromatic amines of concern could be detected in concentrations >30 mg/kg, in 8% of the samples between 5 and 30 mg/kg. The highest measured concentration was 622 mg/kg textile. There is an obvious need to assess consumer health risks for these non-regulated aromatic amines and to fill this gap in the regulation of clothing textiles.

  20. Phosphoric acid loaded azo (-N═N-) based covalent organic framework for proton conduction.

    PubMed

    Chandra, Suman; Kundu, Tanay; Kandambeth, Sharath; Babarao, Ravichandar; Marathe, Yogesh; Kunjir, Shrikant M; Banerjee, Rahul

    2014-05-07

    Two new chemically stable functional crystalline covalent organic frameworkds (COFs) (Tp-Azo and Tp-Stb) were synthesized using the Schiff base reaction between triformylphloroglucinol (Tp) and 4,4'-azodianiline (Azo) or 4,4'-diaminostilbene (Stb), respectively. Both COFs show the expected keto-enamine form, and high stability toward boiling water, strong acidic, and basic media. H3PO4 doping in Tp-Azo leads to immobilization of the acid within the porous framework, which facilitates proton conduction in both the hydrous (σ = 9.9 × 10(-4) S cm(-1)) and anhydrous state (σ = 6.7 × 10(-5) S cm(-1)). This report constitutes the first emergence of COFs as proton conducting materials.

  1. Decolorization and degradation of xenobiotic azo dye Reactive Yellow-84A and textile effluent by Galactomyces geotrichum.

    PubMed

    Govindwar, Sanjay P; Kurade, Mayur B; Tamboli, Dhawal P; Kabra, Akhil N; Kim, Pil Joo; Waghmode, Tatoba R

    2014-08-01

    Galactomyces geotrichum MTCC 1360 exhibited 86% decolorization of azo dye Reactive Yellow-84A (50mgL(-1)) within 30h at 30°C and pH 7.0 under static condition. Examination of azoreductase, laccase and tyrosinase enzyme activities confirmed their prominent role in Reactive Yellow-84A degradation. Considerable reduction of COD (73%) and TOC (62%) during degradation of the dye was indicative of conversion of complex dye into simple products, which were further analyzed by HPLC, FTIR, GC-MS and HPTLC. The degradation products were identified as 4(5-hydroxy, 4-amino cyclopentane) sulfobenzene and 4(5-hydroxy cyclopentane) sulfobenzene by GC-MS. In addition, when G. geotrichum was applied to decolorize textile effluent, it showed 85% of true color removal (ADMI removal) within 72h, along with a significant reduction in TOC and COD. Phytotoxicity studies revealed the less toxic nature of degraded Reactive Yellow-84A as compared to original dye.

  2. Degradation efficiency and mechanism of azo dye RR2 by a novel ozone aerated internal micro-electrolysis filter.

    PubMed

    Zhang, Xian-Bing; Dong, Wen-Yi; Sun, Fei-Yun; Yang, Wei; Dong, Jiao

    2014-07-15

    A newly designed ozone aerated internal micro-electrolysis filter (OIEF) was developed to investigate its degradation efficiencies and correlated reaction mechanisms of RR2 dye. Complete decolorization and 82% TOC removal efficiency were stably achieved in OIEF process. Based on the comprehensive experimental results, an empirical equation was proposed to illustrate the effects of initial dye concentration and ozone dosage rate on color removal. The results indicated that OIEF process could be operated at wide pH range without significant treatment efficiencies change, while the optimum pH for RR2 dye degradation was 9.0. There were 15, 8 and 6 kinds of identified intermediates during ozonation, IE and OIEF treatment processes, respectively. Less identified intermediates and their lower concentrations in OIEF may attribute to its rather excellent mineralization performance. It was found that ozonation, Fe(2+)/Fe(3+) catalyzed ozonation, the redox reactions of electro-reduction and electro-oxidation are the most important mechanisms in OIEF process. The catalytic effect of Fe(2+)/Fe(3+) would induce mutual conversion between dissolved Fe(2+) and Fe(3+), and then decrease the dissolution rate of ZVI. The excellent treatment performance proved that the OIEF process is one promising technology applied for reactive azo dyes and other refractory wastewater treatment.

  3. Simultaneous decolorization and biohydrogen production from xylose by Klebsiella oxytoca GS-4-08 in presence of azo dyes with sulfonate and carboxyl groups.

    PubMed

    Yu, Lei; Cao, Ming-Yue; Wang, Peng-Tao; Wang, Shi; Yue, Ying-Rong; Yuan, Wen-Duo; Qiao, Wei-Chuan; Wang, Fei; Song, Xin

    2017-03-10

    Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anti-counterfeiting paper, which further increases the complexity of wastewater. This study is the first paper to report that xylose could serve as the sole carbon source for a pure culture-Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g l(-1) of xylose as the substrate, a maximum xylose utilization rate (URXyl) and a hydrogen molar yield (HMY) were obtained as 93.99% and 0.259 mol H2 mol(-1) xylose, respectively. Biohydrogen kinetics and e(-) equiv balance calculations indicated that MR penetrates and intracellularly inhibits on both pentose phosphate pathway and pyruvate fermentation pathway, while MO was independent of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period whether with the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain was also proved if the xylose is sufficient, and not affected by toxic substances which usually exists in such wastewater except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes.Importance The pulp and paper industry is a major industry in many developing countries and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amount of refractory contaminants, such as lignin, whose reclamation is considered economic

  4. Ultrasound for low temperature dyeing of wool with acid dye.

    PubMed

    Ferrero, F; Periolatto, M

    2012-05-01

    The possibility of reducing the temperature of conventional wool dyeing with an acid levelling dye using ultrasound was studied in order to reach exhaustion values comparable to those obtained with the standard procedure at 98 °C, obtaining dyed samples of good quality. The aim was to develop a laboratory method that could be transferred at industrial level, reducing both the energy consumption and fiber damage caused by the prolonged exposure to high temperature without the use of polluting auxiliary agents. Dyeings of wool fabrics were carried out in the temperature range between 60 °C and 80 °C using either mechanical or ultrasound agitation of the bath and coupling the two methods to compare the results. For each dyeing, the exhaustion curves of the dye bath were determined and the better results of dyeing kinetics were obtained with ultrasound coupled with mechanical stirring. Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasonic efficiency were calculated in comparison with mechanical stirring alone. In the presence of ultrasound the absorption rate constants increased by at least 50%, at each temperature, confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound was ascribed to the pre-exponential factor of the Arrhenius equation. It was also shown that the effect of ultrasound at 60 °C was just on the dye bath, practically unaffecting the wool fiber surface, as confirmed by the results of SEM analysis. Finally, fastness tests to rubbing and domestic laundering yielded good values for samples dyed in ultrasound assisted process even at the lower temperature. These results suggest the possibility, thanks to the use of ultrasound, to obtain a well equalized dyeing on wool working yet at 60°C, a temperature process strongly lower than 98°C, currently used in industry

  5. Batch and fixed-bed adsorption of tartrazine azo-dye onto activated carbon prepared from apricot stones

    NASA Astrophysics Data System (ADS)

    Albroomi, H. I.; Elsayed, M. A.; Baraka, A.; Abdelmaged, M. A.

    2016-02-01

    This work describes the potential of utilizing prepared activated carbon from apricot stones as an efficient adsorbent material for tartrazine (TZ) azo-dye removal in a batch and dynamic adsorption system. The results revealed that activated carbons with well-developed surface area (774 m2/g) and pore volume (1.26 cm3/g) can be manufactured from apricot stones by H3PO4 activation. In batch experiments, effects of the parameters such as initial dye concentration and temperature on the removal of the dye were studied. Equilibrium was achieved in 120 min. Adsorption capacity was found to be dependent on the initial concentration of dye solution, and maximum adsorption was found to be 76 mg/g at 100 mg/L of TZ. The adsorption capacity at equilibrium (q e) increased from 22.6 to 76 mg/g with an increase in the initial dye concentrations from 25 to 100 mg/L. The thermodynamic parameters such as change in free energy (ΔG 0), enthalpy (ΔH 0) and entropy (ΔS 0) were determined and the positive value of (ΔH) 78.1 (K J mol-1) revealed that adsorption efficiency increased with an increase in the process temperature. In fixed-bed column experiments, the effect of selected operating parameters such as bed depth, flow rate and initial dye concentration on the adsorption capacity was evaluated. Increase in bed height of adsorption columns leads to an extension of breakthrough point as well as the exhaustion time of adsorbent. However, the maximum adsorption capacities decrease with increases of flow rate. The breakthrough data fitted well to bed depth service time and Thomas models with high coefficient of determination, R 2 ≥ 94.

  6. Potential of the aquatic fern Azolla filiculoides in biodegradation of an azo dye: modeling of experimental results by artificial neural networks.

    PubMed

    Khataee, A R; Movafeghi, A; Vafaei, F; Lisar, S Y Salehi; Zarei, M

    2013-01-01

    The potential of an aquatic fern, Azolla filiculoides, in phytoremediation of a mono azo dye solution, C.I. Acid Blue 92 (AB92), was studied. The effects of operational parameters such as reaction time, initial dye concentration, fern fresh weight, pH, temperature and reusability of the fern on biodegradation efficiency were investigated. The intermediate compounds produced by biodegradation process were analyzed using GC-MS analysis. An artificial neural network (ANN) model was developed to predict the biodegradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R2 = 0.961). The effects of AB92 solutions (10 and 20 mg L(-1)) on growth, chlorophylls and carotenoids content, activity of antioxidant enzymes such as superoxide dismutase, peroxidase and catalase and formation of malondialdehyde were analyzed. AB92 generally showed inhibitory effects on the growth. Moreover, photosynthetic pigments in the fronds significantly decreased in the treatments. An increase was detected for lipid peroxidation and antioxidant enzymes activity, suggesting that AB92 caused reactive oxygen species production in Azolla fronds, which were scavenged by induced activities of antioxidant enzymes.

  7. Effectiveness of Rice Agricultural Waste, Microbes and Wetland Plants in the Removal of Reactive Black-5 Azo Dye in Microcosm Constructed Wetlands.

    PubMed

    Saba, Beenish; Jabeen, Madeeha; Khalid, Azeem; Aziz, Irfan; Christy, Ann D

    2015-01-01

    Azo dyes are commonly generated as effluent pollutants by dye using industries, causing contamination of surface and ground water. Various strategies are employed to treat such wastewater; however, a multi-faceted treatment strategy could be more effective for complete removal of azo dyes from industrial effluent than any single treatment. In the present study, rice husk material was used as a substratum in two constructed wetlands (CWs) and augmented with microorganisms in the presence of wetland plants to effectively treat dye-polluted water. To evaluate the efficiency of each process the study was divided into three levels, i.e., adsorption of dye onto the substratum, phytoremediation within the CW and then bioremediation along with the previous two processes in the augmented CW. The adsorption process was helpful in removing 50% dye in presence of rice husk while 80% in presence of rice husk biocahr. Augmentation of microorganisms in CW systems has improved dye removal efficiency to 90%. Similarly presence of microorganisms enhanced removal of total nitrogen (68% 0 and Total phosphorus (75%). A significant improvement in plant growth was also observed by measuring plant height, number of leaves and leave area. These findings suggest the use of agricultural waste as part of a CW substratum can provide enhanced removal of textile dyes.

  8. Synthesis and evaluation of simple naked-eye colorimetric chemosensors for anions based on azo dye-thiosemicarbazones.

    PubMed

    Radchatawedchakoon, Widchaya; Sangsuwan, Withsakorn; Kruanetr, Senee; Sakee, Uthai

    2014-01-01

    A series of novel, highly selective azo dye-thiosemicarbazones based anion sensors (3e-f) have been synthesized from the condensation reaction between thiosemicarbazide and six different azo salicylaldehydes. The structure of the sensors was confirmed by spectroscopic methods. The selectivity and sensitivity in the recognition for acetate anion over other anions such as fluoride, chloride, iodide and dihydrogenphosphate anions were determined by naked-eyes and UV-vis spectra. The color of the solution containing sensor had an obvious change from light yellow to orange only after the addition of acetate anion in aqueous solution (water/dimethylsulfoxide, 7:3, v/v) while other anions did not cause obvious color change. The anion recognition property of the receptor via proton-transfer is monitored by UV-vis titration and (1)H NMR spectroscopy. Under condition in aqueous solution of sensor 3e (water/dimethylsulfoxide, 7:3, v/v), linearity range for the quantification of acetate anion was 1-22 μM and limit of detection (LOD) of acetate anion was 0.71 μM.

  9. Synthesis and evaluation of simple naked-eye colorimetric chemosensors for anions based on azo dye-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Radchatawedchakoon, Widchaya; Sangsuwan, Withsakorn; Kruanetr, Senee; Sakee, Uthai

    2014-03-01

    A series of novel, highly selective azo dye-thiosemicarbazones based anion sensors (3e-f) have been synthesized from the condensation reaction between thiosemicarbazide and six different azo salicylaldehydes. The structure of the sensors was confirmed by spectroscopic methods. The selectivity and sensitivity in the recognition for acetate anion over other anions such as fluoride, chloride, iodide and dihydrogenphosphate anions were determined by naked-eyes and UV-vis spectra. The color of the solution containing sensor had an obvious change from light yellow to orange only after the addition of acetate anion in aqueous solution (water/dimethylsulfoxide, 7:3, v/v) while other anions did not cause obvious color change. The anion recognition property of the receptor via proton-transfer is monitored by UV-vis titration and 1H NMR spectroscopy. Under condition in aqueous solution of sensor 3e (water/dimethylsulfoxide, 7:3, v/v), linearity range for the quantification of acetate anion was 1-22 μM and limit of detection (LOD) of acetate anion was 0.71 μM.

  10. Enhanced decolorization and biodegradation of textile azo dye Scarlet R by using developed microbial consortium-GR.

    PubMed

    Saratale, R G; Saratale, G D; Kalyani, D C; Chang, J S; Govindwar, S P

    2009-05-01

    A developed consortium-GR, consisting of Proteus vulgaris NCIM-2027 (PV) and Micrococcus glutamicus NCIM-2168 (MG), completely decolorized an azo dye Scarlet R under static anoxic condition with an average decolorization rate of 16,666 microg h(-1); which is much faster than that of the pure cultures (PV, 3571 microg h(-1); MG, 2500 microg h(-1)). Consortium-GR gave best decolorization performance with nearly complete mineralization of Scarlet R (over 90% TOC and COD reduction) within 3h, much shorter relative to the individual strains. Induction in the riboflavin reductase and NADH-DCIP reductase was observed in the consortium, suggesting the involvement of these enzymes during the fast decolorization process. The FTIR and GC-MS analysis showed that 1,4-benzenediamine was formed during decolorization/degradation of Scarlet R by consortium-GR. Phytotoxicity studies revealed no toxicity of the biodegraded products of Scarlet R by consortium-GR. In addition, consortium-GR applied for mixture of industrial dyes showed 88% decolorization under static condition with significant reduction in TOC (62%) and COD (68%) within 72 h, suggesting potential application of this microbial consortium in bioremediation of dye-containing wastewater.

  11. Optical bistability in a silicon nitride microring resonator with azo dye-doped liquid crystal as cladding material.

    PubMed

    Wang, Chun-Ta; Tseng, Chih-Wei; Yu, Jui-Hao; Li, Yuan-Cheng; Lee, Chun-Hong; Jau, Hung-Chang; Lee, Ming-Chang; Chen, Yung-Jui; Lin, Tsung-Hsien

    2013-05-06

    This investigation reports observations of optical bistability in a silicon nitride (SiN) micro-ring resonator with azo dye-doped liquid crystal cladding. The refractive index of the cladding can be changed by switching the liquid crystal between nematic (NLC) and photo-induced isotropic (PHI) states by. Both the NLC and the PHI states can be maintained for many hours, and can be rapidly switched from one state to the other by photo-induced isomerization using 532 nm and 408 nm addressing light, respectively. The proposed device exhibits optical bistable switching of the resonance wavelength without sustained use of a power source. It has a 1.9 nm maximum spectral shift with a Q-factor of over 10000. The hybrid SiN- LC micro-ring resonator possesses easy switching, long memory, and low power consumption. It therefore has the potential to be used in signal processing elements and switching elements in optically integrated circuits.

  12. Decolorization of an azo dye Orange G in microbial fuel cells using Fe(II)-EDTA catalyzed persulfate.

    PubMed

    Niu, Cheng-Gang; Wang, Ying; Zhang, Xue-Gang; Zeng, Guang-Ming; Huang, Da-Wei; Ruan, Min; Li, Xiang-Wei

    2012-12-01

    This study constructed a microbial fuel cell (MFC) using Fe(II)-EDTA catalyzed persulfate as the cathode solutions to decolorize Orange G (OG) and harvest electricity simultaneously. Chelated Fe(2+) could activate persulfate to generate sulfate free radicals (SO(4)(-)) which with high oxidation potential (E(0)=2.6 V) can degrade azo dyes. The influence of some important factors such as pH value of cathode solutions, dosages of K(2)S(2)O(8), Fe(2+) and EDTA were investigated in a two-chamber microbial fuel cell. Under an optimal condition, the maximum power density achieved 91.1 mW m(-2), the OG removal rate was 97.4% and the K(2)S(2)O(8) remaining rate was 47.3% after 12 h. The OG degradation by Fe(II)-EDTA catalyzed persulfate was found to follow the second-order kinetic model.

  13. Rapid isolation of a facultative anaerobic electrochemically active bacterium capable of oxidizing acetate for electrogenesis and azo dyes reduction.

    PubMed

    Shen, Nan; Yuan, Shi-Jie; Wu, Chao; Cheng, Yuan-Yuan; Song, Xiang-Ning; Li, Wen-Wei; Tong, Zhong-Hua; Yu, Han-Qing

    2014-05-01

    In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source.

  14. ANALYSIS OF ANIONIC METALLIZED AZO AND FORMAZAN DYES BY CAPILLARY ELECTROPHORESIS/MASS SPECTROMETRY

    EPA Science Inventory

    Capillary electrophoresis-mass spectrometry was applied to the separation of several anionic dyes containing copper(II), chromium(III), or cobalt(III) as part of the dye molecule. The dyes were separated using a 110 cmX50 mu m uncoated fused-silica capillary and a 5 mM ammonium a...

  15. Synthesis of some transition metal complexes with new heterocyclic thiazolyl azo dye and their uses as sensitizers in photo reactions

    NASA Astrophysics Data System (ADS)

    AL-Adilee, Khalid J.; Abass, Ahmed K.; Taher, Ali M.

    2016-03-01

    A new heterocyclic thiazolylazo dye ligand, 2- [bar2-(4, 5- dimethyl thiazolyl) azo ] -4-Ethoxy Phenol (DMeTAEP), (LH) was synthesized by the diazotization of 4.5-dimethyl thiazolylazonium chloride and coupling with 4- Ethoxy phenol in alkaline alcoholic solution under suitable optimized experimental conditions to yield a new azo dye ligand. The structure of ligand and its complexes was prepared from Co(III), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Ag (I) and Au(III) ions. They confirmed by XRD, SEM, (TG-DTG) thermal analysis, 1H-NMR,UV-visb, mass and FT-IR spectroscopic methods, elemental analysis, atomic absorption, magnetic susceptibility and molar conductance. The mole ratio [M: L], it was also studied which was 1:1 for Ag (I) and Au (III) complexes and 1:2 The rest of the metal complexes. The isolated solid complexes are found to have the general formula [M (L)2 ] Cln.mH2O, where n = 1, m = 0 when M = Co (III) and n = 0, m = 1 when M = Ni (II), and Hg(II) while n = 0 and m = 0 when M = Cu (II), Zn (II), Cd (II) and ]ML (H2O)] of Ag(I) - complex but Au(III)-complex structural formula was [Au(L)Cl] Cl conductivity measurements for prepared complexes showed 1:1 electrolyte for Co(III(and Au(III) complexes and non - electrolyte the rest of complexes. The spectral and analytical data revealed that this ligand behaves as a tridentate chelating agent and coordination number of all metal ions were found to be six except for Ag (I) and Au (III) which was four. The activities of complexes were examined as sensitizers in the photocatalytic reaction of p-nitro aniline (PNA) which is used as a model of water pollutants.

  16. Photo degradation of methyl orange an azo dye by advanced Fenton process using zero valent metallic iron: influence of various reaction parameters and its degradation mechanism.

    PubMed

    Gomathi Devi, L; Girish Kumar, S; Mohan Reddy, K; Munikrishnappa, C

    2009-05-30

    Advanced Fenton process (AFP) using zero valent metallic iron (ZVMI) is studied as a potential technique to degrade the azo dye in the aqueous medium. The influence of various reaction parameters like effect of iron dosage, concentration of H(2)O(2)/ammonium per sulfate (APS), initial dye concentration, effect of pH and the influence of radical scavenger are studied and optimum conditions are reported. The degradation rate decreased at higher iron dosages and also at higher oxidant concentrations due to the surface precipitation which deactivates the iron surface. The rate constant for the processes Fe(0)/UV and Fe(0)/APS/UV is twice compared to their respective Fe(0)/dark and Fe(0)/APS/dark processes. The rate constant for Fe(0)/H(2)O(2)/UV process is four times higher than Fe(0)/H(2)O(2)/dark process. The increase in the efficiency of Fe(0)/UV process is attributed to the cleavage of stable iron complexes which produces Fe(2+) ions that participates in cyclic Fenton mechanism for the generation of hydroxyl radicals. The increase in the efficiency of Fe(0)/APS/UV or H(2)O(2) compared to dark process is due to continuous generation of hydroxyl radicals and also due to the frequent photo reduction of Fe(3+) ions to Fe(2+) ions. Though H(2)O(2) is a better oxidant than APS in all respects, but it is more susceptible to deactivation by hydroxyl radical scavengers. The decrease in the rate constant in the presence of hydroxyl radical scavenger is more for H(2)O(2) than APS. Iron powder retains its recycling efficiency better in the presence of H(2)O(2) than APS. The decrease in the degradation rate in the presence of APS as an oxidant is due to the fact that generation of free radicals on iron surface is slower compared to H(2)O(2). Also, the excess acidity provided by APS retards the degradation rate as excess H(+) ions acts as hydroxyl radical scavenger. The degradation of Methyl Orange (MO) using Fe(0) is an acid driven process shows higher efficiency at pH 3. The

  17. 40 CFR 721.5281 - 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 2-Naphthalenesulfonic acid, 3- -2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, sodium salt, compd. With 2,2â²,2â³-nitrilotris (9CI). 721.5281 Section 721.5281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT...

  18. 40 CFR 721.5281 - 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2-Naphthalenesulfonic acid, 3- -2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, sodium salt, compd. With 2,2â²,2â³-nitrilotris (9CI). 721.5281 Section 721.5281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT...

  19. 40 CFR 721.5281 - 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2-Naphthalenesulfonic acid, 3- -2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, sodium salt, compd. With 2,2â²,2â³-nitrilotris (9CI). 721.5281 Section 721.5281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT...

  20. 40 CFR 721.5281 - 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2-Naphthalenesulfonic acid, 3- -2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, sodium salt, compd. With 2,2â²,2â³-nitrilotris (9CI). 721.5281 Section 721.5281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT...

  1. 40 CFR 721.5281 - 2-Naphthalenesulfonic acid, 3-[[4-[(2,4-dimethyl-6-sulfophenyl)azo]-2-methoxy-5-methylphenyl]azo...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2-Naphthalenesulfonic acid, 3- -2-methoxy-5-methylphenyl]azo]-4-hydroxy-7-(phenylamino)-, sodium salt, compd. With 2,2â²,2â³-nitrilotris (9CI). 721.5281 Section 721.5281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT...

  2. Role of surfactant derived intermediates in the efficacy and mechanism for radiation chemical degradation of a hydrophobic azo dye, 1-phenylazo-2-naphthol.

    PubMed

    Das, Laboni; Chatterjee, Suchandra; Naik, Devidas B; Adhikari, Soumyakanti

    2015-11-15

    A combined methodology involving gamma and pulse radiolysis, product analysis and toxicity studies has been adopted to comprehend the degradation process of a model hydrophobic azo dye, 1-phenylazo-2-naphthol, emphasizing the role of the surfactant, which is an integral part of textile waste. Two new and important findings are underlined in this article. The first is the direct attestation of the hydrazyl radical-parent adduct, formed in the reaction of the dye with e(-)aq followed by protonation and subsequent addition to the unreacted dye molecule. This has been confirmed from concentration dependent studies. Secondly, we have clearly shown that in the reaction of hydroxyl radical with the dye in Triton X-100 media, the initially produced TX radicals cause reductive degradation of the dye. Identification and detailed analysis of HPLC and GCMS data reveals that similar products are formed in both the reactions of e(-)aq and OH radicals. Moreover, the cytotoxicity of 10(-4)moldm(-3) dye was found to be reduced significantly after irradiation. Thus, the present study not only depicts new pathways for the degradation of hydrophobic azo dye, but also demonstrates the role of a surfactant in the entire process.

  3. TiO2/palygorskite composite nanocrystalline films prepared by surfactant templating route: synergistic effect to the photocatalytic degradation of an azo-dye in water.

    PubMed

    Stathatos, E; Papoulis, D; Aggelopoulos, C A; Panagiotaras, D; Nikolopoulou, A

    2012-04-15

    Microfibrous palygorskite clay mineral and nanocrystalline TiO(2) are incorporating in the preparation of nanocomposite films on glass substrates via sol-gel route at 500°C. The synthesis involves a simple chemical method employing nonionic surfactant molecule as pore directing agent along with the acetic acid-based sol-gel route without direct addition of water molecules. Drying and thermal treatment of composite films lead to the elimination of organic material while ensure the formation of TiO(2) nanoparticles homogeneously distributed on the surface of the palygorskite microfibers. TiO(2) nanocomposite films without cracks consisted of small crystallites in size (12-16 nm) and anatase crystal phase was found to cover palygorskite microfibers. The composite films were characterized by microscopy techniques, UV-vis, IR spectroscopy, and porosimetry methods in order to examine their structural properties. Palygorskite/TiO(2) composite films with variable quantities of palygorskite (0-2 w/w ratio) were tested as new photocatalysts in the photo-discoloration of Basic Blue 41 azo-dye in water. These nanocomposite films proved to be very promising photocatalysts and highly effective to dye's discoloration in spite of the small amount of immobilized palygorskite/TiO(2) catalyst onto glass substrates. 3:2 palygorskite/TiO(2) weight ratio was finally the most efficient photocatalyst while reproducible discoloration results of the dye were obtained after three cycles with same catalyst. It was also found that palygorskite showed a positive synergistic effect to the TiO(2) photocatalysis.

  4. Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

    NASA Astrophysics Data System (ADS)

    Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2016-04-01

    In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment.

  5. Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

    PubMed Central

    Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2016-01-01

    In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment. PMID:27121278

  6. Synthesized TiO2/ZSM-5 composites used for the photocatalytic degradation of azo dye: Intermediates, reaction pathway, mechanism and bio-toxicity

    NASA Astrophysics Data System (ADS)

    Zhou, Kefu; Hu, Xin-Yan; Chen, Bor-Yann; Hsueh, Chung-Chuan; Zhang, Qian; Wang, Jiajie; Lin, Yu-Jung; Chang, Chang-Tang

    2016-10-01

    In this study, a one-step solid dispersion method was used to synthesize titanium dioxide (TiO2)/Zeolite Socony Mobil-5 (ZSM-5) composites with substantially reduced time and energy consumption. A degradation efficiency of more than 95% was achieved within 10 min using 50% PTZ (synthesized TiO2/ZSM-5 composites with TiO2 contents of 50 wt% loaded on ZSM-5) at pH 7 and 25 °C. The possible degradation pathway of azo-dye Reactive Black 5 (RB5) was investigated using gas chromatography-mass spectrometry and ion chromatography (IC). The bonds between the N atoms and naphthalene groups are likely attacked first and cleaved by hydroxyl radicals, ultimately resulting in the decolorization and mineralization of the azo dye. A comparative assessment of the characteristics of abiotic and biotic dye decolorization was completed. In addition, the toxicity effects of the degradation intermediates of azo-dye RB5 on cellular respiratory activity were analyzed. The bio-toxicity results showed that the decay rate constants of CO2 production from the azo-dye RB5 samples at different degradation times increased initially and subsequently decreased, indicating that intermediates of higher toxicity could adhere to the catalyst surface and gradually destroyed by further photocatalytic oxidation. Additionally, EDTA (hole scavengers) and t-BuOH (radical scavengers) were used to detect the main active oxidative species in the system. The results showed that the hydroxyl radicals are the main oxidation species in the photocatalytic process.

  7. Variation in optoelectronic properties of azo dye-sensitized TiO2 semiconductor interfaces with different adsorption anchors: carboxylate, sulfonate, hydroxyl and pyridyl groups.

    PubMed

    Zhang, Lei; Cole, Jacqueline M; Dai, Chencheng

    2014-05-28

    The optoelectronic properties of four azo dye-sensitized TiO2 interfaces are systematically studied as a function of a changing dye anchoring group: carboxylate, sulfonate, hydroxyl, and pyridyl. The variation in optoelectronic properties of the free dyes and those in dye/TiO2 nanocomposites are studied both experimentally and computationally, in the context of prospective dye-sensitized solar cell (DSSC) applications. Experimental UV/vis absorption spectroscopy, cyclic voltammetry, and DSSC device performance testing reveal a strong dependence on the nature of the anchor of the optoelectronic properties of these dyes, both in solution and as dye/TiO2 nanocomposites. First-principles calculations on both an isolated dye/TiO2 cluster model (using localized basis sets) and each dye modeled onto the surface of a 2D periodic TiO2 nanostructure (using plane wave basis sets) are presented. Detailed examination of these experimental and computational results, in terms of light harvesting, electron conversion and photovoltaic device performance characteristics, indicates that carboxylate is the best anchoring group, and hydroxyl is the worst, whereas sulfonate and pyridyl groups exhibit competing potential. Different sensitization solvents are found to affect critically the extent of dye adsorption achieved in the dye-sensitization of the TiO2 semiconductor, especially where the anchor is a pyridyl group.

  8. Aerobic biodegradation of Azo dye by Bacillus cohnii MTCC 3616; an obligately alkaliphilic bacterium and toxicity evaluation of metabolites by different bioassay systems.

    PubMed

    Prasad, A S Arun; Rao, K V Bhaskara

    2013-08-01

    An obligate alkaliphilic bacterium Bacillus cohnii MTCC 3616 aerobically decolorized a textile azo dye Direct Red-22 (5,000 mg l⁻¹) with 95 % efficiency at 37 °C and pH 9 in 4 h under static conditions. The decolorization of Direct Red-22 (DR-22) was possible through a broad pH (7-11), temperature (10-45 °C), salinity (1-7 %), and dye concentration (5-10 g l⁻¹) range. Decolorization of dye was assessed by UV-vis spectrophotometer with reduction of peak intensity at 549 nm (λ(max)). Biodegradation of dye was analyzed by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The FTIR spectrum revealed that B. cohnii specifically targeted azo bond (N=N) at 1,614.42 cm⁻¹ to break down Direct Red-22. Formation of metabolites with different retention times in HPLC analysis further confirmed the degradation of dye. The phytotoxicity test with 5,000 mg l⁻¹ of untreated dye showed 80 % germination inhibition in Vigna mungo, 70 % in Sorghum bicolor and 80 % in Vigna radiata. No germination inhibition was noticed in all three plants by DR-22 metabolites at 5,000 mg l⁻¹. Biotoxicity test with Artemia salina proved the lethality of the azo dye at LC₅₀ of 4 and 8 % for degraded metabolites by causing death of its nauplii compared to its less toxic-degraded metabolites. Bioaccumulation of dye was observed in the mid-gut of A. salina. The cytogenotoxicity assay on the meristematic root tip cells of Allium cepa further confirmed the cytotoxic nature of azo dye (DR-22) with decrease in mitotic index (0.5 % at 500 ppm) and increase in aberrant index (4.56 %) over 4-h exposure period. Genotoxic damages (lagging chromosome, metaphase cluster, chromosome bridges, and dye accumulation in cytoplasm) were noticed at different stages of cell cycle. The degraded metabolites had negligible cytotoxic and genotoxic effects.

  9. Sediment contaminated with the Azo Dye disperse yellow 7 alters cellular stress- and androgen-related transcription in Silurana tropicalis larvae.

    PubMed

    Mathieu-Denoncourt, Justine; Martyniuk, Christopher J; de Solla, Shane R; Balakrishnan, Vimal K; Langlois, Valérie S

    2014-01-01

    Azo dyes are the most commonly used type of dye, accounting for 60-70% of all organic dye production worldwide. They are used as direct dyes in the textile, leather, printing ink, and cosmetic industries. The aim of this study was to assess the lethal and sublethal effects of the disazo dye Disperse Yellow 7 (DY7) in frogs to address a knowledge gap regarding mechanisms of toxicity and the potential for endocrine disrupting properties. Larvae of Silurana tropicalis (Western clawed frog) were exposed to DY7-contaminated water (0 to 22 μg/L) and sediment (0 to 209 μg/g) during early larval development. The concentrations used included the range of similar azo dyes found in surface waters in Canada. A significant decrease in tadpole survivorship was observed at 209 μg/g while there was a significant increase in malformations at the two highest concentrations tested in sediment. In the 209 μg/g treatment, DY7 significantly induced hsp70 (2.5-fold) and hsp90 (2.4-fold) mRNA levels, suggesting that cells required oxidative protection. The same treatment also altered the expression of two androgen-related genes: decreased ar (2-fold) and increased srd5a2 (2.6-fold). Furthermore, transcriptomics generated new hypotheses regarding the mechanisms of toxic action of DY7. Gene network analysis revealed that high concentrations of DY7 in sediment induced cellular stress-related gene transcription and affected genes associated with necrotic cell death, chromosome condensation, and mRNA processing. This study is the first to report on sublethal end points for azo dyes in amphibians, a growing environmental pollutant of concern for aquatic species.

  10. Optimization of the azo dye Procion Red H-EXL degradation by Fenton's reagent using experimental design.

    PubMed

    Rodrigues, Carmen S D; Madeira, Luis M; Boaventura, Rui A R

    2009-05-30

    Chemical oxidation by Fenton's reagent of a reactive azo dye (Procion Deep Red H-EXL gran) solution has been optimized making use of the experimental design methodology. The variables considered for the oxidative process optimization were the temperature and the initial concentrations of hydrogen peroxide and ferrous ion, for a dye concentration of 100mg/L at pH 3.5, the latter being fixed after some preliminary runs. Experiments were carried out according to a central composite design approach. The methodology employed allowed to evaluate and identify the effects and interactions of the considered variables with statistical meaning in the process response, i.e., in the total organic carbon (TOC) reduction after 120 min of reaction. A quadratic model with good adherence to the experimental data in the domain analysed was developed, which was used to plot the response surface curves and to perform process optimization. It was concluded that temperature and ferrous ion concentration are the only variables that affect TOC removal, and due to the cross-interactions, the effect of each variable depends on the value of the other one, thus affecting positively or negatively the process response.

  11. Remediation of Water Contaminated with an Azo Dye: An Undergraduate Laboratory Experiment Utilizing an Inexpensive Photocatalytic Reactor

    NASA Astrophysics Data System (ADS)

    Bumpus, John A.; Tricker, Jennifer; Andrzejewski, Ken; Rhoads, Heather; Tatarko, Matthew

    1999-12-01

    The construction and use of an inexpensive photocatalytic reactor that utilizes titanium dioxide as the photocatalyst for wastewater treatment is described. In these experiments and in supplementary material, students are made aware that a variety of techniques have been developed to treat wastewaters, including those generated by the chemical industry. Water contaminated with the azo dye Congo Red was selected as an example of how one might treat contaminated water from a textile manufacturing facility. These experiments emphasize that, in addition to product development, chemists must also be concerned with waste treatment. A summary of the theory of titanium dioxide-mediated photocatalysis is provided. The phenomenon of photosensitization is also discussed. The usefulness of Congo Red is summarized and a brief history of this dye is given. In addition to being inexpensive, the photocatalytic reactor described is easy to construct and uses a readily available low-wattage fluorescent light. An important feature of this reactor is that the heat generated by the light source is readily dissipated by the water undergoing treatment. Thus no special cooling apparatus is required. One of the most important aspects of this work is that it provides a wide variety of continuing research suggestions that would be suitable and readily accomplished in undergraduate departments and high school laboratories; even those where budgetary priorities are a major concern. Use of this reactor would also enable students to design systems to treat "real-world" wastes, including some that are generated in instructional laboratories.

  12. Structure and reactivity of thiazolium azo dyes: UV-visible, resonance Raman, NMR, and computational studies of the reaction mechanism in alkaline solution.

    PubMed

    Abbott, Laurence C; Batchelor, Stephen N; Moore, John N

    2013-03-07

    UV-visible absorption, resonance Raman, and (1)H NMR spectroscopy, allied with density functional theory (DFT) calculations, have been used to study the structure, bonding, and alkaline hydrolysis mechanism of the cationic thiazloium azo dye, 2-[2-[4-(diethylamino)phenyl]diazenyl]-3-methyl-thiazolium (1a), along with a series of six related dyes with different 4-dialkylamino groups and/or other phenyl ring substituents (2a-c, 3a-c) and the related isothiazolium azo dye, 5-[2-[4-(dimethylamino)phenyl]diazenyl]-2-methyl-isothiazolium (4). These diazahemicyanine dyes are calculated to have a similar low-energy structure that is cis, trans at the (iso)thiazolium-azo group, and for which the calculated Raman spectra provide a good match with the experimental data; the calculations on these structures are used to assign and discuss the transitions giving rise to the experimental spectra, and to consider the bonding and its variation between the dyes. UV-visible, Raman, and NMR spectra recorded from minutes to several weeks after raising the pH of an aqueous solution of 1a to ca. 11.5 show that the dominant initial step in the reaction is loss of diethylamine to produce a quinonimine (ca. hours), with subsequent reactions occurring on longer time scales (ca. days to weeks); kinetic analyses give a rate constant of 2.6 × 10(-2) dm(3) mol(-1) s(-1) for reaction of 1a with OH(-). UV-visible spectra recorded on raising the pH of the other dyes in solution show similar changes that are attributed to the same general reaction mechanism, but with different rate constants for which the dependence on structure is discussed.

  13. Protective role of Spirulina feed in a freshwater fish (Poecilia reticulata Peters) exposed to an azo dye-methyl red.

    PubMed

    Sharma, Shweta; Sharma, Subhasini; Sharma, K P

    2005-12-01

    Acute toxicity of an azo dye-methyl red (5-40 ppm) was examined under starving conditions, on two groups of Poecilia reticulata--a freshwater fish, fed on different diets prior to their exposure to dye. Besides natural feed, fish of group-1 also received Spirulina feed for one month (feed population), whereas those of group-2 received only natural feed (non-feed population). The mortality data revealed non-feed population to be more tolerant to feed stress during acute toxicity study, whereas feed population exhibited better tolerance to the combined stress of both feed and methyl red; especially at higher concentrations of the latter. RBCs in methyl red treatments acquired different shapes (poikilocytosis) and an increase in their size (anisocytosis) was also noticed. Percentage of such abnormal RBCs was almost equal in both feed and non-feed populations, except at a lower concentration (5 ppm), at which percentage of poikilocytic RBCs was lesser in the feed population. RBC counts in the control non-feed fish (34.5 x 10(4)/mm3) were significantly lower than control feed population (50.0 x 10(4) /mm3). Their number decreased with an increase in methyl red concentrations in non-feed population (9-26%), but percent reduction in RBC counts was almost similar (20-26%) at various concentrations of methyl red (5-30 ppm) in the feed population. Despite reduction in RBC counts, feed population did not suffer from anemia in methyl red treatments, as evident by their RBC counts which were almost equal to control fish of non-feed population. The results suggest that Spirulina feed improves tolerance of test organism towards methyl red manifested by noticeable reduction in the cytotoxic effects on RBCs and a lower mortality rate at higher concentrations of dye.

  14. Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris.

    PubMed

    Hernández-Zamora, Miriam; Cristiani-Urbina, Eliseo; Martínez-Jerónimo, Fernando; Perales-Vela, Hugo Virgilio; Ponce-Noyola, Teresa; Montes-Horcasitas, María del Carmen; Cañizares-Villanueva, Rosa Olivia

    2015-07-01

    Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L(-1), respectively. The maximum adsorption capacity at equilibrium was 200 mg g(-1). The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC50 = 17.0 mg L(-1)), followed by Ceriodaphnia dubia (EC50 = 3.32 mg L(-1)). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent.

  15. Photocatalytic activity against azo dye and cytotoxicity on MCF-7 cell lines of zirconium oxide nanoparticle mediated using leaves of Lagerstroemia speciosa.

    PubMed

    Sai Saraswathi, V; Santhakumar, K

    2017-04-01

    Metal oxide nanoparticles are gaining interest in recent years. The present paper explains about the green synthesis of zirconium oxide nanoparticles (ZrO NPs) mediated from the leaves of Lagerstroemia speciosa. The prepared ZrO NPs were characterized by UV-vis spectroscopy, FT-IR, X-ray diffraction analysis (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and Thermogravimetric Analysis (TGA). The photocatalytic activity of ZrO NPs was studied for azo dye by exposing to sunlight. The azo dye was degraded up to 94.58%. Also the ZrO NPs were studied for in vitro cytotoxicity activity against breast cancer cell lines-MCF-7 and evaluated by MTT assay. The cell morphological changes were recorded by light microscope. The cells viability was seen at 500μg/mL when compared against control. Hence the research highlights, that the method was simple, eco-friendly towards environment by phytoremediation activity of the azo dye and cytotoxicity activity against MCF-7 cell lines. Hence the present paper may help to further explore the metal nanoparticle for its potential applications.

  16. Photoinduced reordering in thin azo-dye films and light-induced reorientation dynamics of the nematic liquid-crystal easy axis.

    PubMed

    Kiselev, Alexei D; Chigrinov, V G; Pasechnik, S V; Dubtsov, A V

    2012-07-01

    We theoretically study the kinetics of photoinduced reordering triggered by linearly polarized (LP) reorienting light in thin azo-dye films that were initially illuminated with LP ultraviolet pumping beam. The process of reordering is treated as a rotational diffusion of molecules in the light intensity-dependent mean-field potential. The two-dimensional diffusion model which is based on the free energy rotational Fokker-Planck equation and describes the regime of in-plane reorientation is generalized to analyze the dynamics of the azo-dye order parameter tensor at varying polarization azimuth of the reorienting light. It is found that, in the photosteady state, the intensity of LP reorienting light determines the scalar order parameter (the largest eigenvalue of the order parameter tensor), whereas the steady state orientation of the corresponding eigenvector (the in-plane principal axis) depends solely on the polarization azimuth. We show that, under certain conditions, reorientation takes place only if the reorienting light intensity exceeds its critical value. Such threshold behavior is predicted to occur in the bistability region provided that the initial principal axis lies in the polarization plane of reorienting light. The model is used to interpret the experimental data on the light-induced azimuthal gliding of the liquid-crystal easy axis on photoaligned azo-dye substrates.

  17. Periphyton biofilms: A novel and natural biological system for the effective removal of sulphonated azo dye methyl orange by synergistic mechanism.

    PubMed

    Shabbir, Sadaf; Faheem, Muhammad; Ali, Naeem; Kerr, Philip G; Wu, Yonghong

    2017-01-01

    Due to their large scale use, azo dyes are adversely affecting aquatic fauna and flora as well as humans. The persistent nature of sulphonated azo dyes makes them potential ecotoxic hazards. The aim of the present study was to employ a proficient, locally available biomaterial, viz. periphyton (i.e. epiphyton, epilithon or metaphyton), for removal of the azo dye, methyl orange (MO). Results showed that the periphytic biofilms are capable of completely removing comparatively high concentrations (up to 500 mg L(-1)) of MO from wastewater. The removal of MO occurs by a synergistic mechanism involving bioadsorption and biodegradation processes. The adsorption of MO by periphyton can be described by pseudo-second order kinetics. Elovich and intraparticle diffusion models as well as Langmuir equations fit well to the MO adsorption process. FTIR analysis of MO and its metabolites demonstrated biotransformation into simpler compounds within 72 h. GC-MS/MS analysis showed the conversion of MO into simpler compounds such as phenol, ethyl acetate and acetyl acetate. The results indicated that periphyton is a promising biomaterial for the complete removal of MO from wastewater and that the treatment process has the potential for in situ removal of MO at contaminated sites.

  18. Microwave-enhanced UV/H2O2 degradation of an azo dye (tartrazine): optimization, colour removal, mineralization and ecotoxicity.

    PubMed

    Parolin, Fernanda; Nascimento, Ulisses Magalhães; Azevedo, Eduardo Bessa

    2013-01-01

    This study optimizes two factors, pH and initial [H2O2], in the ultraviolet (UV)/H2O2/microwave (MW) process through experimental design and assesses the effect of MWs on the colour removal of an azo-dye (tartrazine) solution that was favoured by an acidic pH. The estimated optimal conditions were: initial [H2O2] = 2.0 mmol L(-1) and pH = 2.6, at 30 +/- 2 degrees C. We obtained colour removals of approximately 92% in 24 min of irradiation (EDL, 244.2 W), following zero order kinetics: k = (3.9 +/- 0.52) x 10(-2) a.u. min(-1) and R2 = 0.989. Chemical and biological oxygen demand were significantly removed. On the other hand, the carbon content, biodegradability and ecotoxicity (Lactuca sativa) remained approximately the same. The UV/H2O2/MW process was shown to be eight times faster than other tested processes (MW, H2O2, H2O2/MW, and UV/MW).

  19. Analyses of the genotoxic and mutagenic potential of the products formed after the biotransformation of the azo dye Disperse Red 1.

    PubMed

    Chequer, Farah Maria Drumond; Lizier, Thiago Mescoloto; de Felício, Rafael; Zanoni, Maria Valnice Boldrin; Debonsi, Hosana Maria; Lopes, Norberto Peporine; Marcos, Ricard; de Oliveira, Danielle Palma

    2011-12-01

    Azo dyes constitute the largest class of synthetic dyes. Following oral exposure, these dyes can be reduced to aromatic amines by the intestinal microflora or liver enzymes. This work identified the products formed after oxidation and reduction of the dye Disperse Red 1, simulating hepatic biotransformation and evaluated the mutagenic potential of the resultant solution. Controlled potential electrolysis was carried out on dye solution using a Potentiostat/Galvanostat. HPLC-DAD and GC/MS were used to determine the products generated after the oxidation/reduction process. The Salmonella/microsome assay with the strains TA98 and YG1041 without S9, and the mouse lymphoma assay (MLA) using the thymidine kinase (Tk) gene, were used to evaluate the mutagenicity of the products formed. Sulfate 2-[(4-aminophenyl)ethylamino]-ethanol monohydrate, nitrobenzene, 4-nitro-benzamine and 2-(ethylphenylamino)-ethanol were detected. This dye has already being assigned as mutagenic in different cell system. In addition, after the oxidation/reduction process the dye still had mutagenic activity for the Salmonella/microsome assay. Nevertheless, both the original dye Disperse Red 1 and its treated solutions showed negative results in the MLA. The present results suggest that the ingestion of water and food contaminated with this dye may represent human and environmental health problem, due to the generation of harmful compounds after biotransformation.

  20. TiO2/Ag modified penta-bismuth hepta-oxide nitrate and its adsorption performance for azo dye removal.

    PubMed

    Abdullah, Eshraq Ahmed; Abdullah, Abdul Halim; Zainal, Zulkarnain; Hussein, Mohd Zobir; Ban, Tan Kar

    2012-01-01

    A modified hydrophilic penta-bismuth hepta-oxide nitrate (Bi5O7NO3) surface was synthesized via a precipitation method using TiO2 and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono- and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy (XPS) results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure Bi5O7NO3; however, the presence of hydrophilic centres such as TiO2 and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.

  1. Solar photocatalytic degradation of mono azo methyl orange and diazo reactive green 19 in single and binary dye solutions: adsorbability vs photodegradation rate.

    PubMed

    Ong, Soon-An; Min, Ohm-Mar; Ho, Li-Ngee; Wong, Yee-Shian

    2013-05-01

    The objective of this study was to examine the effects of adsorbability and number of sulfonate group on solar photocatalytic degradation of mono azo methyl orange (MO) and diazo Reactive Green 19 (RG19) in single and binary dye solutions. The adsorption capacity of MO and RG19 onto the TiO₂ was 16.9 and 26.8 mg/g, respectively, in single dye solution, and reduced to 5.0 and 23.1 mg/g, respectively, in the binary dye solution. The data obtained for photocatalytic degradation of MO and RG19 in single and binary dye solution were well fitted with the Langmuir-Hinshelwood kinetic model. The pseudo-first-order rate constants of diazo RG19 were significant higher than the mono azo MO either in single or binary dye solutions. The higher number of sulfonate group in RG19 contributed to better adsorption capacity onto the surface of TiO₂ than MO indicating greater photocatalytic degradation rate.

  2. Influence of process parameters on the photodegradation of synthesized azo pyridone dye in TiO2 water suspension under simulated sunlight.

    PubMed

    Dostanić, Jasmina M; Loncarević, Davor R; Banković, Predrag T; Cvetković, Olga G; Jovanović, Dusan M; Mijin, Dusan Z

    2011-01-01

    Photocatalytic degradation of synthesized azo pyridone dye (5-(4-sulpho phenylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone), in aqueous solutions by simulated sunlight in the presence of commercial TiO(2), Aeroxide P25, was studied. The reaction kinetics analysis showed that photodegradation exhibits pseudo first-order kinetics according to Langmuir-Hinshelwood model. The effects of various process parameters on the photocatalytic degradation were investigated. The optimal catalyst content and pH were determined. A decrease in the reaction rate was observed upon the increase of the initial dye concentration. Degradation of the dye was enhanced by hydrogen peroxide, but it was inhibited by ethanol. The influence of temperature was studied, and the energy of activation was determined. According to total organic carbon (TOC) analysis, 54% of TOC remained when 100% of the dye was decolorized. Although the intermediates were not determined in this study, the TOC results clearly indicate their presence during the reaction. In addition, photocatalytic degradation of simulated dyehouse effluents, containing tested azo pyridone dye and associated auxiliary chemicals was investigated.

  3. Inducing hetero-aggregation of different azo dyes through electrostatic self-assembly.

    PubMed

    Mariani, Giacomo; Di, Zhenyu; Kutz, Anne; Schweins, Ralf; Gröhn, Franziska

    2017-03-16

    Combining chemically different building blocks in supramolecular nanoparticles is a promising key to tailored structures and functionalities. Pi-pi heterostacks of dye molecules form upon electrostatic self-assembly with a polyelectrolyte, resulting in stable ternary nanoassemblies in aqueous solution. Core-shell spheres, cylinders and flexible cylinders result, which exhibit new shapes different from the binary systems. Particle shapes can be tuned via the dye composition.

  4. The effect of high-energy radiation on aqueous solution of Acid Red 1 textile dye

    NASA Astrophysics Data System (ADS)

    Földváry, Cs. M.; Wojnárovits, L.

    2007-08-01

    The effect of high-energy radiation on Acid Red 1 (AR1) azo-dye solution was investigated by UV-Vis spectroscopy and chemical oxygen demand (COD) measurements. Doses in the order of 10 kGy cause complete decolouration of the 10 -3-10 -4 mol dm -3 solutions; however, for complete mineralization doses higher by 1-2 order of magnitude are needed. Hydrated electrons and H rad atom are more effective in fading reaction, while the rad OH radicals have higher efficiency in mineralization. The HO 2•/O 2•- radical-radical anion pair is rather inefficient in fading reaction.

  5. Comparative study of toxicity of azo dye Procion Red MX-5B following biosorption and biodegradation treatments with the fungi Aspergillus niger and Aspergillus terreus.

    PubMed

    Almeida, E J R; Corso, C R

    2014-10-01

    Azo dyes are an important class of environmental contaminants and are characterized by the presence of one or more azo bonds (-N=N-) in their molecular structure. Effluents containing these compounds resist many types of treatments due to their molecular complexity. Therefore, alternative treatments, such as biosorption and biodegradation, have been widely studied to solve the problems caused by these substances, such as their harmful effects on the environment and organisms. The aim of the present study was to evaluate biosorption and biodegradation of the azo dye Procion Red MX-5B in solutions with the filamentous fungi Aspergillus niger and Aspergillus terreus. Decolorization tests were performed, followed by acute toxicity tests using Lactuca sativa seeds and Artemia salina larvae. Thirty percent dye removal of the solutions was achieved after 3 h of biosorption. UV-Vis spectroscopy revealed that removal of the dye molecules occurred without major molecular changes. The acute toxicity tests confirmed lack of molecular degradation following biosorption with A. niger, as toxicity to L. sativa seed reduced from 5% to 0%. For A. salina larvae, the solutions were nontoxic before and after treatment. In the biodegradation study with the fungus A. terreus, UV-Vis and FTIR spectroscopy revealed molecular degradation and the formation of secondary metabolites, such as primary and secondary amines. The biodegradation of the dye molecules was evaluated after 24, 240 and 336 h of treatment. The fungal biomass demonstrated considerable affinity for Procion Red MX-5B, achieving approximately 100% decolorization of the solutions by the end of treatment. However, the solutions resulting from this treatment exhibited a significant increase in toxicity, inhibiting the growth of L. sativa seeds by 43% and leading to a 100% mortality rate among the A. salina larvae. Based on the present findings, biodegradation was effective in the decolorization of the samples, but generated

  6. Characterization of azo dyes on Pt and Pt/polyaniline/dispersed Pt electrodes

    NASA Astrophysics Data System (ADS)

    Molina, J.; Fernández, J.; del Río, A. I.; Bonastre, J.; Cases, F.

    2012-06-01

    The electrochemical characterization of two organic dyes (amaranth and procion orange MX-2R) has been performed on Pt electrodes and Pt electrodes coated with polyaniline and dispersed Pt. Electrodes with different Pt loads have been synthesized and characterized obtaining that a load of 300 μg cm-2 was the optimum one. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was employed to observe the distribution and morphology of the Pt nanoparticles. The electroactivity of the electrodes has also been characterized by means of scanning electrochemical microscopy (SECM). The chemical characterization of Pt dispersed Pani coated Pt electrodes (Pt-Pani-Pt) was performed by means of X-ray photoelectron spectroscopy (XPS). The electrochemical characterization of the dyes has been performed by means of cyclic voltammetry. Voltammograms have shown that the presence of the dyes diminishes characteristic Pt oxidation and reduction peaks. However, redox processes due to the dyes, appeared in the voltammograms. The different species responsible of these redox processes were generated in the vicinity of the electrode and were not adsorbed on the electrode surface since after stirring, the different redox processes disappeared. Characterization with different scan rates showed that redox processes of both dyes were controlled by diffusion.

  7. Quantitative extraction and concentration of synthetic water-soluble acid dyes from aqueous media using a quinine-chloroform solution

    SciTech Connect

    Kobayashi, F.; Ozawa, N.; Hanai, J.; Isobe, M.; Watabe, T.

    1986-12-01

    Twenty-one water-soluble acid dyes, including eleven azo, five triphenylmethane four xanthene, one naphthol derivatives, used at practical concentrations for food coloration, were quantitatively extracted from water and various carbonated beverages into a 0.1 M quinine-chloroform solution in the presence of 0.5 M boric acid by brief shaking. Quantitative extraction of these dyes was also accomplished by the 0.1 M quinine-chloroform solution made conveniently from chloroform, quinine hydrochloride, and sodium hydroxide added successively to water or beverages containing boric acid. Quinine acted as a countercation on the dyes having sulfonic and/or carboxylic acid group(s) to form chloroform-soluble ion-pair complexes. The diacidic base alkaloid interacted with each acid group of mono-, di-, tri-, and tetrasulfonic acid dyes approximately in the ratio 0.8-0.9 to 1. The dyes in the chloroform solution were quantitatively concentrated into a small volume of sodium hydroxide solution also by brief shaking. The convenient quinine-chloroform method was applicable to the quantitative extraction of a mixture of 12 dyes from carbonated beverages, which are all currently used for food coloration. A high-pressure liquid chromatographic method is also presented for the systematic separation and determination of these 12 dyes following their concentration into the aqueous alkaline solution. The chromatogram was monitored by double-wavelength absorptiometry in the visible and ultraviolet ray regions.

  8. Graphene oxide supported copper oxide nanoneedles: An efficient hybrid material for removal of toxic azo dyes

    NASA Astrophysics Data System (ADS)

    Rajesh, Rajendiran; Iyer, Sahithya S.; Ezhilan, Jayabal; Kumar, S. Senthil; Venkatesan, Rengarajan

    2016-09-01

    Herein, we report a simple, one step synthesis of hybrid copper oxide nanoneedles on graphene oxide sheets (GO-CuONNs) through sonochemical method. The present method affords a facile mean for controlling effective concentration of the active CuO nanoneedles on the graphene oxide sheets, and also offers the necessary stability to the resulting GO-CuONNs structure for adsorption transformations.Furthermore, this hybrid GO-CuONNs is successfully employed in the removal of a series of hazardous ionic organic dyes namely coomassie brilliant blue, methylene blue, congo red and amidoblack 10B. Through careful investigation of the material, we found that the synergetic effect between CuONNs and GO play a significant role in the adsorption of all the dyes studied. The prepared hybrid material contains both hydrophobic and hydrophilic environment which is expected to enhance the electrostatic interaction between the adsorbent and the dye molecules, consequently favouring the adsorption process.

  9. Azo Dyes and Their Interfacial Activity: Implications for Multiphase Flow Experiments

    SciTech Connect

    Tuck, D.M.

    1999-04-21

    Interfacial effects play an important role in governing multiphase fluid behavior in porous media (Neustadter 1984; Tuck et al. 1988). For instance, several dimensionless numbers have been developed to express important force ratios applicable to multiphase flow in porous media (Morrow and Songkran 1981; Chatzis and Morrow 1984; Wardlaw 1988; Pennell et al. 1996; Dawson and Roberts 1997). These force ratios emphasize the importance of interfacial properties. Our objectives are to provide chemical information regarding the dyes commonly used in multiphase flow visualization studies and to show the surface chemistry effects of the most commonly used dye, Sudan IV, in the tetrachloroethylene (PCE)-water-glass system

  10. Photocatalytic degradation of azo dyes using Au:TiO2, gamma-Fe2O3:TiO2 functional nanosystems.

    PubMed

    Jagadale, Tushar; Kulkarni, Manjusha; Pravarthana, D; Ramadan, Wegdan; Thakur, Pragati

    2012-02-01

    We report photocatalytic degradation studies on Navy Blue HE2R (NB) dye on significant details as a representative from the class of azo dyes using functional nanosystems specifically designed to allow a strong photocatalytic activity. A modified sol-gel route was employed to synthesize Au and gamma-Fe2O3 modified TiO2 nanoparticles (NPs) at low temperature. The attachment strategy is better because it allows clear surface of TiO2 to remain open for photo-catalysis. X-ray diffraction, Raman and UV-VIS spectroscopy studies showed the presence of gold and iron oxide phases along-with the anatase TiO2 phase. TEM studies showed TiO2 nanocomposite particles of size approximately 10-12 nm. A detailed investigation on heterogeneous photocatalytic performance for Navy Blue HE2R dye was done using the as-synthesized catalysts Au:TiO2 and gamma-Fe2O3:TiO2 in aqueous suspension under 8 W low-pressure mercury vapour lamp irradiation. Also, the photocatalytic degradation of Amranth and Orange G azo dyes were studied. The surface modified TiO2 NPs showed significantly improved photocatalytic activity as compared to pure TiO2. Exposure of the dye to the UV light in the presence of pure and gold NPs attached TiO2 catalysts caused dye degradation of about approximately 20% and approximately 80%, respectively, in the first couple of hours. In the presence of gamma-Fe2O3 NPs attached TiO2, a remarkable approximately 95% degradation of the azo dye was observed only in the first 15 min of UV exposure. The process parameters for the optimum catalytic activity are established which lead to a complete decoloration and substantial dye degradation, supported by the values of the Chemical Oxygen Demand (COD) approximately 93% and Total Organic Carbon (TOC) approximately 65% of the treated dye solution after 5 hours on the employment of the UV/Au:TiO2/H2O2 photocatalytic process.

  11. Unveiling characteristics of a bioelectrochemical system with polarity reversion for simultaneous azo dye treatment and bioelectricity generation.

    PubMed

    Sun, Jian; Zhang, Yaping; Liu, Guoguang; Ning, Xunan; Wang, Yujie; Liu, Jingyong

    2015-09-01

    A novel bioelectrochemical system (BES) operated with polarity reversion was explored for simultaneous anaerobic/aerobic treatment of azo dye and production of bioelectricity under extremely low buffer. The Congo red was first decolorized in anode, with completed color removal in 35 h. The resultant decolorization intermediates were then mineralized after the anode reversed to aerobic biocathode, evidenced by 55 % chemical oxygen demand (COD) removal in 200 h. The mineralization efficiency was further increased to 70 % when the period of the half-cycle was prolonged to 375 h. Meanwhile, the BES produced a continuous stable positive/negative alternate voltage output under 5 mM phosphate buffer because of the self-neutralization of the accumulated protons and hydroxyl ions in electrolyte. The electrode performance was significantly improved, which was indicated by alleviated electrode polarization, due to in situ use of accumulated protons and hydroxyl ions and enhanced electron transfer in the presence of Congo red and its degradation intermediates, which resulted in 1.05-fold increases in maximum power density (67.5 vs. 32.9 mW/m(2)). An analysis of the microbial diversity in the biofilm revealed that the biofilm was dominated by facultative bacteria with functional roles in contaminant degradation and electricity generation.

  12. Properties of nucleic acid staining dyes used in gel electrophoresis.

    PubMed

    Haines, Alicia M; Tobe, Shanan S; Kobus, Hilton J; Linacre, Adrian

    2015-03-01

    Nucleic acid staining dyes are used for detecting nucleic acids in electrophoresis gels. Historically, the most common dye used for gel staining is ethidium bromide, however due to its toxicity and mutagenicity other dyes that are safer to the user and the environment are preferred. This Short Communication details the properties of dyes now available and their sensitivity for detection of DNA and their ability to permeate the cell membrane. It was found that GelRed™ was the most sensitive and safest dye to use with UV light excitation, and both GelGreen™ and Diamond™ Nucleic Acid Dye were sensitive and the safer dyes using blue light excitation.

  13. Application of activated carbon derived from 'waste' bamboo culms for the adsorption of azo disperse dye: kinetic, equilibrium and thermodynamic studies.

    PubMed

    Wang, Lianggui

    2012-07-15

    The utilization of activated carbon derived from 'waste' bamboo culms (BAC) for the removal of Disperse Red 167 (DR167), an azo disperse dye, was investigated. Studies of the properties of the adsorbent, the effect of contact time, the initial pH of the solution, the initial concentration of the dye solution and temperature indicated that a low initial pH or concentration of dye solution favors the adsorption process; temperature exerts a greater effect on the removal of azo disperse red 167 dye from aqueous solution. Kinetic and isotherm data were fitted to five non-linear kinetic and nine non-linear isotherm equations. In addition, the fits were evaluated in terms of the non-linear coefficient, Chi-square test, Marquardt's percent standard deviation error function and small-sample-corrected Akaike Information Criterion (AICc) methodology. The results showed that the AICc analysis was the best statistical tool for analyzing the data, the intra-particle diffusion and the pseudo-first-order models played important roles in the controlling rate step, and the Temkin equation best described the BAC isotherm data. Furthermore, the thermodynamic analysis indicated that the adsorption was a spontaneous, endothermic, entropy-increasing and physical process. Two types of commercial activated carbon, Filtrasorb 400 and Filtrasorb (F400 and F300), were used as contrast adsorbents. The contrast experiments revealed that BAC exhibits similar properties to F400 and F300. The utilization of bamboo wastes as carbon precursors is feasible.

  14. 454-Pyrosequencing analysis of highly adapted azo dye-degrading microbial communities in a two-stage anaerobic-aerobic bioreactor treating textile effluent.

    PubMed

    Köchling, Thorsten; Ferraz, Antônio Djalma Nunes; Florencio, Lourdinha; Kato, Mario Takayuki; Gavazza, Sávia

    2017-03-01

    Azo dyes, which are widely used in the textile industry, exhibit significant toxic characteristics for the environment and the human population. Sequential anaerobic-aerobic reactor systems are efficient for the degradation of dyes and the mineralization of intermediate compounds; however, little is known about the composition of the microbial communities responsible for dye degradation in these systems. 454-Pyrosequencing of the 16S rRNA gene was employed to assess the bacterial biodiversity and composition of a two-stage (anaerobic-aerobic) pilot-scale reactor that treats effluent from a denim factory. The anaerobic reactor was inoculated with anaerobic sludge from a domestic sewage treatment plant. Due to the selective composition of the textile wastewater, after 210 days of operation, the anaerobic reactor was dominated by the single genus Clostridium, affiliated with the Firmicutes phylum. The aerobic biofilter harbored a diverse bacterial community. The most abundant phylum in the aerobic biofilter was Proteobacteria, which was primarily represented by the Gamma, Delta and Epsilon classes followed by Firmicutes and other phyla. Several bacterial genera were identified that most likely played an essential role in azo dye degradation in the investigated system.

  15. Optimization and modelling of synthetic azo dye wastewater treatment using Graphene oxide nanoplatelets: Characterization toxicity evaluation and optimization using Artificial Neural Network.

    PubMed

    Banerjee, Priya; Sau, Shubhra; Das, Papita; Mukhopadhayay, Aniruddha

    2015-09-01

    Azo dyes pose a major threat to current civilization by appearing in almost all streams of wastewater. The present investigation was carried out to examine the potential of Graphene oxide (GO) nanoplatelets as an efficient, cost-effective and non-toxic azo dye adsorbent for efficient wastewater treatment. The treatment process was optimized using Artificial Neural Network for maximum percentage dye removal and evaluated in terms of varying operational parameters, process kinetics and thermodynamics. A brief toxicity assay was also designed using fresh water snail Bellamya benghalensis to analyze the quality of the treated solution. 97.78% removal of safranin dye was obtained using GO as adsorbent. Characterization of GO nanoplatelets (using SEM, TEM, AFM and FTIR) reported the changes in its structure as well as surface morphology before and after use and explained its prospective as a good and environmentally benign adsorbent in very low quantities. The data recorded when subjected to different isotherms best fitted the Temkin isotherm. Further analysis revealed the process to be endothermic and chemisorption in nature. The verdict of the toxicity assay rendered the treated permeate as biologically safe for discharge or reuse in industrial and domestic purposes.

  16. THE CONTRIBUTION OF AZO DYES TO THE MUTAGENIC ACTIVITY OF THE CRISTAIS RIVER

    EPA Science Inventory

    To verify if compounds within the discharge of a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the treated industrial effluent, raw and treated water, and the sludge produced by a ...

  17. AZO DYES ARE MAJOR CONTRIBUTORS TO THE MUTAGENIC ACTIVITY DETECTED IN THE CRISTAIS RIVER WATERS

    EPA Science Inventory

    To determine if compounds from a dye processing plant were contributing to the mutagenicity repeatedly found in the Cristais River, Sao Paulo, Brazil, we chemically characterized the treated industrial effluent, raw and treated water, and the sludge produced by a Drinking Water T...

  18. Mineralization and Detoxification of the Carcinogenic Azo Dye Congo Red and Real Textile Effluent by a Polyurethane Foam Immobilized Microbial Consortium in an Upflow Column Bioreactor

    PubMed Central

    Lade, Harshad; Govindwar, Sanjay; Paul, Diby

    2015-01-01

    A microbial consortium that is able to grow in wheat bran (WB) medium and decolorize the carcinogenic azo dye Congo red (CR) was developed. The microbial consortium was immobilized on polyurethane foam (PUF). Batch studies with the PUF-immobilized microbial consortium showed complete removal of CR dye (100 mg·L−1) within 12 h at pH 7.5 and temperature 30 ± 0.2 °C under microaerophilic conditions. Additionally, 92% American Dye Manufactureing Institute (ADMI) removal for real textile effluent (RTE, 50%) was also observed within 20 h under the same conditions. An upflow column reactor containing PUF-immobilized microbial consortium achieved 99% CR dye (100 mg·L−1) and 92% ADMI removal of RTE (50%) at 35 and 20 mL·h−l flow rates, respectively. Consequent reduction in TOC (83 and 79%), COD (85 and 83%) and BOD (79 and 78%) of CR dye and RTE were also observed, which suggested mineralization. The decolorization process was traced to be enzymatic as treated samples showed significant induction of oxidoreductive enzymes. The proposed biodegradation pathway of the dye revealed the formation of lower molecular weight compounds. Toxicity studies with a plant bioassay and acute tests indicated that the PUF-immobilized microbial consortium favors detoxification of the dye and textile effluents. PMID:26086710

  19. Mineralization and Detoxification of the Carcinogenic Azo Dye Congo Red and Real Textile Effluent by a Polyurethane Foam Immobilized Microbial Consortium in an Upflow Column Bioreactor.

    PubMed

    Lade, Harshad; Govindwar, Sanjay; Paul, Diby

    2015-06-16

    A microbial consortium that is able to grow in wheat bran (WB) medium and decolorize the carcinogenic azo dye Congo red (CR) was developed. The microbial consortium was immobilized on polyurethane foam (PUF). Batch studies with the PUF-immobilized microbial consortium showed complete removal of CR dye (100 mg·L-1) within 12 h at pH 7.5 and temperature 30 ± 0.2 °C under microaerophilic conditions. Additionally, 92% American Dye Manufactureing Institute (ADMI) removal for real textile effluent (RTE, 50%) was also observed within 20 h under the same conditions. An upflow column reactor containing PUF-immobilized microbial consortium achieved 99% CR dye (100 mg·L-1) and 92% ADMI removal of RTE (50%) at 35 and 20 mL·h-l flow rates, respectively. Consequent reduction in TOC (83 and 79%), COD (85 and 83%) and BOD (79 and 78%) of CR dye and RTE were also observed, which suggested mineralization. The decolorization process was traced to be enzymatic as treated samples showed significant induction of oxidoreductive enzymes. The proposed biodegradation pathway of the dye revealed the formation of lower molecular weight compounds. Toxicity studies with a plant bioassay and acute tests indicated that the PUF-immobilized microbial consortium favors detoxification of the dye and textile effluents.

  20. Occurrence and risk assessment of an azo dye - The case of Disperse Red 1.

    PubMed

    Vacchi, Francine Inforçato; Von der Ohe, Peter Carsten; Albuquerque, Anjaína Fernandes de; Vendemiatti, Josiane Aparecida de Souza; Azevedo, Carina Cristina Jesus; Honório, Jaqueline Gonçalves; Silva, Bianca Ferreira da; Zanoni, Maria Valnice Boldrin; Henry, Theodore B; Nogueira, Antonio J; Umbuzeiro, Gisela de Aragão

    2016-08-01

    Water quality criteria to protect aquatic life are not available for most disperse dyes which are often used as commercial mixtures in textile coloration. In this study, the acute and chronic toxicity of the commercial dye Disperse Red 1 (DR1) to eight aquatic organisms from four trophic levels was evaluated. A safety threshold, i.e. Predicted No-Effect Concentration (PNEC), was derived based on the toxicity information of the commercial product and the purified dye. This approach was possible because the toxicity of DR1 was accounting for most of the toxicity of the commercial mixture. A long-term PNEC of 60 ng L(-1) was proposed, based on the most sensitive chronic endpoint for Daphnia similis. A short-term PNEC of 1800 ng L(-1) was proposed based on the most sensitive acute endpoint also for Daphnia similis. Both key studies have been evaluated with the new "Criteria for Reporting and Evaluating ecotoxicity Data" (CRED) methodology, applying more objective criteria to assess the quality of toxicity tests, resulting in two reliable and relevant endpoints with only minor restrictions. HPLC-MS/MS was used to quantify the occurrence of DR1 in river waters of three sites, influenced by textile industry discharges, resulting in a concentration range of 50-500 ng L(-1). The risk quotients for DR1 obtained in this work suggest that this dye can pose a potential risk to freshwater biota. To reduce uncertainty of the derived PNEC, a fish partial or full lifecycle study should be performed.

  1. Pseudomonas extremorientalis BU118: a new salt-tolerant laccase-secreting bacterium with biotechnological potential in textile azo dye decolourization.

    PubMed

    Neifar, Mohamed; Chouchane, Habib; Mahjoubi, Mouna; Jaouani, Atef; Cherif, Ameur

    2016-06-01

    The present investigation focused on screening of a new potent strain for laccase production and optimizing the process parameters to achieve the maximum enzymatic decolourization of textile azo dye Congo red. Seven hydrocarbonoclastic bacterial strains were selected as positive in laccase production in solid medium using 2,6 dimethoxyphenol as an enzyme activity indicator. The best enzyme producer Pseudomonas extremorientalis BU118 showed a maximum laccase activity of about 7000 U/L of wheat bran under solid-state conditions. The influence of different concentrations of dye, enzyme, salt and various incubation times on Congo red decolourization was studied using response surface methodology to find the optimum conditions required for maximum decolourization by P. extremorientalis laccase. The enzyme exhibited a remarkable colour removal capability over a wide range of dye and salt concentrations. The above results show the potential use of this bacterial laccase in the biological treatment of the textile effluent.

  2. Accelerating biodegradation of a monoazo dye Acid Orange 7 by using its endogenous electron donors.

    PubMed

    Sun, Weihua; Zhang, Chengji; Chen, Jun; Zhang, Bingbing; Zhang, Hongzhuan; Zhang, Yongming; Chen, Lujun

    2017-02-15

    Biodegradation of a monoazo dye - Acid Orange 7 (AO7) was investigated by using an internal circulation baffled biofilm reactor. For accelerating AO7 biodegradation, endogenous electron donors produced from AO7 by UV photolysis were added into the reactor. The result shows that AO7 removal rate can be accelerated by using its endogenous electron donors, such as sulfanilic and aniline. When initial AO7 concentration was 13.6mg/L, electron donors generated by 8h UV photolysis were added into the same system. The biodegradation rate 0.4mg(0.05)h(-1) was enhanced 60% than that without adding electron donor. Furthermore, sulfanilic and aniline were found to be the main endogenous electron carriers, which could accelerate the steps of the azo dye biodegradation.

  3. Enhancement of anaerobic degradation of azo dye with riboflavin and nicotinamide adenine dinucleotide harvested by osmotic lysis of wasted fermentation yeasts.

    PubMed

    Victral, Davi M; Dias, Heitor R A; Silva, Silvana Q; Baeta, Bruno E L; Aquino, Sérgio F

    2017-02-01

    The study presented here aims at identifying the source of redox mediators (riboflavin), electron carriers nicotinamide adenine dinucleotide (NAD) and carbon to perform decolorization of azo dye under anaerobic conditions after osmotic shock pretreatment of residual yeast from industrial fermentation. Pretreatment conditions were optimized by Doehlert experiment, varying NaCl concentration, temperature, yeast density and time. After the optimization, the riboflavin concentration in the residual yeast lysate (RYL) was 46% higher than the one present in commercial yeast extract. Moreover, similar NAD concentration was observed in both extracts. Subsequently, two decolorization experiments were performed, that is, a batch experiment (48 h) and a kinetic experiment (102 h). The results of the batch experiment showed that the use of the RYL produced by the optimized method increased decolorization rates and led to color removal efficiencies similar to those found when using the commercial extract (∼80%) and from 23% to 50% higher when compared to the control (without redox mediators). Kinetics analysis showed that methane production was also higher in the presence of yeast extract and RYL, and biogas was mostly generated after stabilization of color removal. In all kinetics experiments the azo dye degradation followed the pseudo-second-order model, which suggested that there was a concomitant adsorption/degradation of the dye on the biomass cell surface. Therefore, results showed the possibility of applying the pretreated residual yeast to improve color removal under anaerobic conditions, which is a sustainable process.

  4. Oxidation pathways for ozonation of azo dyes in a semi-batch reactor: a kinetic parameters approach.

    PubMed

    Lopez, A; Benbelkacem, H; Pic, J S; Debellefontaine, H

    2004-03-01

    In this study ozone and the H2O2/O3 oxidation system are used to decolorize aqueous solutions of Orange II (Or-II) and Acid Red 27 (AR-27). Investigations are carried out in a semi-batch bubble column reactor. A system of series-parallel reactions is proposed to describe the mechanism of dye oxidation. The stoichiometric ratio for the first reaction is found to be 1 mol dye per mol O3, while the overall ozone demand for both reactions one and two is found to be 5 and 6 moles for Or-II and AR-27 respectively. Molecular and radical kinetics are compared: a radical scavenger, t-butanol, can be added to ensure only the molecular reaction of ozone, or hydrogen peroxide can be supplied through a peristaltic pump, to initiate radical reactivity. Results reveal that colour removal is ensured by direct ozone attack. For both dyes, TOC removal efficiencies of 50 - 60 % are obtained by the action of the hydroxyl free radical. However, this is not improved by addition of H2O2, thus demonstrating that organic species alone ensure HO degrees radical production during ozonation. Both the mass transfer and the ozone reactivity with the dyes are considered to evaluate the kinetic parameters for the molecular pathway.

  5. Enhanced degradation of azo dye in wastewater by pulsed discharge plasma coupled with MWCNTs-TiO2/γ-Al2O3 composite photocatalyst.

    PubMed

    Li, Xin; Wang, Tiecheng; Qu, Guangzhou; Liang, Dongli; Hu, Shibin

    2016-05-01

    In order to improve the photocatalytic performance of TiO2 in pulsed discharge plasma systems, easily recycled multi-walled carbon nanotubes (MWCNTs)-TiO2 supported on γ-Al2O3 (MWCNTs-TiO2/γ-Al2O3) composite photocatalyst were prepared. The morphology and physicochemical properties of the prepared catalysts were investigated using XRD, SEM, FTIR and UV-vis spectroscopy. The photocatalytic activity was evaluated by degradation of azo dye acid orange II (AO7) in wastewater under pulsed discharge plasma. The results indicate that the MWCNTs-TiO2/γ-Al2O3 composite catalyst possesses enhanced photocatalytic activity facilitating the decomposition of AO7 compared with TiO2/γ-Al2O3 composite in pulsed discharge plasma systems. Under pulsed discharge plasma, almost 100% AO7 is degraded by the MWCNTs-TiO2/γ-Al2O3 composite after 60 min at optimal conditions. The degradation efficiency of AO7 is also affected by the dosage of the composite catalyst and pulsed discharge peak voltage. As the amount of MWCNTs-TiO2/γ-Al2O3 composite and pulsed discharge peak voltage increases, the degradation efficiency of AO7 increases. The photocatalyst was implemented for 6 cycles and the degradation efficiency of AO7 remains higher than 85% under pulsed discharge plasma. Results indicate that the catalyst displays easy separation and minimal deactivation after several uses. Possible decomposition mechanisms were also investigated. MWCNTs are capable of improving the photocatalytic activity of TiO2/γ-Al2O3 composite in pulsed discharge plasma systems primarily due to the photo-induced-electron absorption effect and the electron trap effect of MWCNTs. The results of this study establish the feasibility and potential implementation of MWCNTs-TiO2/γ-Al2O3 composites in pulsed discharge plasma systems for the degradation of dye wastewater.

  6. Sprayed nanostructured TiO2 films for efficient photocatalytic degradation of textile azo dye.

    PubMed

    Stambolova, Irina; Shipochka, Capital Em Cyrillicaria; Blaskov, Vladimir; Loukanov, Alexandrе; Vassilev, Sasho

    2012-12-05

    Spray pyrolysis procedure for preparation of nanostructured TiO(2) films with higher photocatalytic effectiveness and longer exploitation life is presented in this study. Thin films of active nanocrystalline TiO(2) were obtained from titanium isopropoxide, stabilized with acetyl acetone and characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The activity of sprayed nanostructured TiO(2) is tested for photocatalytic degradation of Reactive Black 5 dye with concentrations up to 80 ppm. Interesting result of the work is the reduction of toxicity after photocatalytic treatment of RB5 with TiO(2), which was confirmed by the lower percentage of mortality of Artemia salina. It was proved that the film thickness, conditions of post deposition treatment and the type of the substrate affected significantly the photocatalytic reaction. Taking into account that the parameters are interdependent, it is necessary to optimize the preparation conditions in order to synthesize photocatalytic active films.

  7. Solar photodegradation of a textile azo dye using synthesized ZnO/Bentonite.

    PubMed

    Boutra, B; Trari, M

    2017-03-01

    The present work is devoted to the synthesis of a new photocatalyst ZnO (7.5%)/Bentonite prepared by impregnation method and its successful application for the degradation of Solophenyl Red 3BL (SR 3BL) under solar light (∼660 W/m(2)). The X-ray diffraction (XRD) indicates mixed phases of the nanocomposite catalyst (ZnO/Bentonite), characterized by scanning electron microscopy, X-ray fluorescence and attenuated total reflection. The optical properties confirm the presence of the Wurtzite ZnO phase with an optical gap of 3.27 eV. The catalyst dose (0.25-1 gL(-1)), pH solution (2.5-11) and initial dye concentration (5-75 mg/L) are optimized. The optimal pH (∼6.7) is close to the natural environment. The photodegradation yield increases with decreasing the SR 3BL concentration. The equilibrium is reached within 160 min and the data are well fitted by the Langmuir-Hinshelwood model; the SR 3BL disappearance obeys to a first-order kinetic with an apparent rate constant of 10(-)(2) mn(-)(1). The best yield of SR 3BL photodegradation (92%) is achieved for a concentration of 5 mg/L and a catalyst dose of 0.75 gL(-1) at free pH.

  8. Highly efficient visible light mediated azo dye degradation through barium titanate decorated reduced graphene oxide sheets

    NASA Astrophysics Data System (ADS)

    Rastogi, Monisha; Kushwaha, H. S.; Vaish, Rahul

    2016-03-01

    This study investigates BaTiO3 decorated reduced graphene oxide sheets as a potential visible light active catalyst for dye degradation (Rhodamine B). The composites were prepared through conventional hydrothermal synthesis technique using hydrazine as a reducing agent. A number of techniques have been employed to affirm the morphology, composition and photocatalytic properties of the composites; these include UV-visible spectrophotoscopy that assisted in quantifying the concentration difference of Rhodamine B. The phase homogeneity of the composites was examined through x-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) was employed to confirm the orientation of the BaTiO3 particles over the reduced graphene oxide sheets. Photoluminescence (PL) emission spectra assisted in determining the surface structure and excited state of the catalyst. Fourier transformed-infrared (FTIR) spectra investigated the vibrations and adsorption peak of the composites, thereby ascertaining the formation of reduced graphene oxide. In addition, diffuse reflectance spectroscopy (DRS) demonstrated an enhanced absorption in the visible region. The experimental investigations revealed that graphene oxide acted as charge collector and simultaneously facilitated surface adsorption and photo-sensitization. It could be deduced that BaTiO3-reduced graphene oxide composites are of significant interest the field of water purification through solar photocatalysis. [Figure not available: see fulltext.

  9. Optically tunable/switchable omnidirectionally spherical microlaser based on a dye-doped cholesteric liquid crystal microdroplet with an azo-chiral dopant.

    PubMed

    Lin, Jia-De; Hsieh, Meng-Hung; Wei, Guan-Jhong; Mo, Ting-Shan; Huang, Shuan-Yu; Lee, Chia-Rong

    2013-07-01

    This paper presents an optically wavelength-tunable and intensity-switchable dye-doped cholesteric liquid crystal (DDCLC) spherical microlaser with an azo-chiral dopant. Experimental results present that two functions of optical control - tunability of lasing wavelength and switchability of lasing intensity - can be obtained for this spherical microlaser at low and high intensity regimes of non-polarized UV irradiation, respectively. If the DDCLC microdroplet is subjected to weak UV irradiation, azo-chiral molecules may transform to the bent cis state at a low concentration rate. The effect can slightly decrease the local order of LCs and thus the helical twisting power of the CLC in the microdroplet. As a result, the CLC pitch may become slightly elongated, which will cause the gradual red-shift of both omnidirectional PBG and lasing emission of the DDCLC spherical microdroplet. In contrast, when the microdroplet is subjected to strong UV irradiation, numerous azo-chiral molecules may simultaneously change to bent cis-isomers to seriously disarrange the helical texture of the CLC, which will quickly deform the PBG and deactivate the lasing emission of the microdroplet. Prolonged irradiation of a blue beam after strong UV irradiation may cause the cis azo-chiral molecules quickly convert back rod-like trans-isomers, which may then regenerate the CLC Bragg onion and PBG structures and reactivate the lasing emission of the microdroplet. Optical control of the DDCLC spherical microlaser is realized on a scale of seconds and minutes when UV irradiation is strong and weak, respectively. The 3D DDCLC spherical microlaser is a highly promising controllable 3D micro-light source or microlaser (e.g., all-optical 3D single photon microlaser) for applications of 3D all-optical integrated photonics, laser displays, and biomedical imaging and therapy, and as a 3D UV microdosagemeter or microsensor.

  10. Adsorption of acid dye onto organobentonite.

    PubMed

    Baskaralingam, P; Pulikesi, M; Elango, D; Ramamurthi, V; Sivanesan, S

    2006-02-06

    Removal of Acid Red 151 from aqueous solution at different dye concentrations, adsorbent doses and pH has been studied. The bentonite clay has been modified using cationic surfactants, which has been confirmed using XRD and FT-IR analyses. Experimental result has shown that the acidic pH favours the adsorption. The adsorption isotherms are described by means of Langmuir and Freundlich isotherms. The adsorption capacity has been found to be 357.14 and 416.66 mg g(-1) for the cetyldimethylbenzylammonium chloride-bentonite (CDBA-bent) and cetylpyridinium chloride-bentonite (CP-bent), respectively. Kinetic studies show that the adsorption followed second-order kinetics.

  11. Microextraction by packed sorbent and salting-out-assisted liquid-liquid extraction for the determination of aromatic amines formed from azo dyes in textiles.

    PubMed

    Sánchez, Miguel del Nogal; Santos, Patricia Martín; Sappó, Cristina Pérez; Pavón, José Luis Pérez; Cordero, Bernardo Moreno

    2014-02-01

    EU legislation prohibits the use of certain azo dyes which, on reduction, form any of 22 aromatic amines listed in Regulation (EC) 1907/2006 at concentrations above the threshold limit of 30 mg Kg(-1). Two different extraction techniques for the determination of aromatic amines formed from azo dyes in textiles in combination with gas chromatography-mass spectrometry (GC-MS) are described. The first one is based on microextraction by packed sorbent (MEPS) and the other approach involves salting-out-assisted liquid-liquid extraction (SALLE). The influence of several parameters on the efficiency of the extraction using MEPS (sorbent material, sample volume, elution solvent, elution volume and washing steps, among others) and SALLE (extraction volume and amount of salt) were investigated. In addition, chromatographic separation was optimized and quadrupole mass spectrometry was evaluated using the synchronous SIM/scan data acquisition mode. The repeatability (n=8, S/N=3) of the methods, calculated as the relative standard deviation (RSD) was below 15 and 11% for all compounds when MEPS and SALLE were used, respectively. Standard additions procedure was used to quantify the aromatic amines in the textil samples. The detection limits in the samples for both methods were lower than the maximum value allowed by legislation. The results obtained in the analysis of textiles revealed the presence of o-anisidine, p-chloroaniline, 4-chloro-o-toluidine, 2-naphthylamine and 3,3'-dimethoxybenzidine in some of them.

  12. Evaluation of the treatment performance of lab-scaled vertical flow constructed wetlands in removal of organic compounds, color and nutrients in azo dye-containing wastewater.

    PubMed

    Dogdu, Gamze; Yalcuk, Arda

    2016-01-01

    The objective of this study is to examine the treatment performance of vertical flow intermittent feeding constructed wetland (VFCW) in removal of organic pollution, nutrients and color in azo-dye containing wastewater. The systems consisted of PVC reactors, some filling materials such as gravel, sand and zeolite and wetland plants including Typha angustifolia and Canna indica. The average treatment efficiency of the systems for COD, color, sulphate, NH4-N, and PO4-P were in the range of 57-63%, 94-99%, 44-48%, 39-44%, and 84-88%, respectively among the VFCW reactors. It is concluded that VFCW reactor system can effectively be used in the treatment of dye-rich wastewater, especially for the removal of color and in the reduction of COD. Biofilm formation and cleavage of azo bonds could be observed by SEM and FTIR results, respectively. Almost similar NH4-N and PO4-P removal were obtained in all reactors by using same amount of zeolite media.

  13. Solvatochromic behavior of the electronic absorption spectra of gallic acid and some of its azo derivatives

    NASA Astrophysics Data System (ADS)

    Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

    The electronic absorption spectra of gallic acid and its azo derivatives have been studied in various solvents of different polarities. Multiple regression techniques were applied to calculate the regression and correlation coefficients based on an equation that relates the wavenumbers of the absorption band maxima (υmax-) to the solvent parameters; refractive index (n), dielectric constant (D), empirical Kamlet-Taft solvent parameters, π*(dipolarity/polarizability), α (solvent hydrogen-bond donor acidity) and β (solvent hydrogen-bond acceptor basicity). The fitting coefficient obtained from this analysis allows estimating the contribution of each type of interactions relative to total spectral shifts in solution. The dependence of υmax- on the solvent parameters indicates that the obtained bands are affected by specific and non-specific solute-solvent interactions.

  14. Synthesis and spectroscopic characterization of gallic acid and some of its azo complexes

    NASA Astrophysics Data System (ADS)

    Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

    2012-04-01

    A series of gallic acid and azo gallic acid complexes were prepared and characterized by elemental analysis, IR, electronic spectra and magnetic susceptibility. The complexes were of different geometries: Octahedral, Tetrahedral and Square Planar. ESR was studied for copper complexes. All of the prepared complexes were of isotropic nature. The thermal analyses of the complexes were studied by DTA and DSC techniques. The thermodynamic parameters and the thermal transitions, such as glass transitions, crystallization and melting temperatures for some ligands and their complexes were evaluated and discussed. The entropy change values, ΔS#, showed that the transition states are more ordered than the reacting complexes. The biological activities of some ligands and their complexes are tested against Gram positive and Gram negative bacteria. The results showed that some complexes have a well considerable activity against different organisms.

  15. Mutagenic compounds generated from the chlorination of disperse azo-dyes and their presence in drinking water.

    PubMed

    Oliveira, Danielle P; Carneiro, Patrícia A; Rech, Célia M; Zanoni, Maria Valnice B; Claxton, Larry D; Umbuzeiro, Gisela A

    2006-11-01

    The water produced by the Cristais River Drinking Water Treatment Plant (CR-DWTP) repeatedly produced mutagenic responses that could not be explained by the presence of disinfection byproducts (DBPs) generated by the reaction of humic acids and chlorine. In order to determine the possible role of chlorinated dye products in this mutagenic activity, solutions of a black dye commercial product (BDCP) composed of C.I. Disperse Blue 373, C.I. Disperse Orange 37, C.I. Disperse Violet 93, and chemically reduced BDCP (R-BDCP) were chlorinated in a manner similar to that used by the CR-DWTP. The resulting solutions were extracted with XAD-4 along with one drinking water sample collected from the CR-DWTP. All extracts showed mutagenic activity in the Salmonella/microsome assay. Dye components of the BDCP as well as its reduced chlorinated (CI-R-BDCP) derivative were detected in the drinking water sample by analysis with a high performance liquid chromatography/diode array detector (HPLC/DAD). The mutagenicity results of these products suggest that they are, at least in part, accounting for the mutagenic activity detected in the drinking water samples from the Cristais River. The data obtained in this study have environmental and health implications because the chlorination of the BDCP and the R-BDCP leads to the formation of mutagenic compounds (CI-BDCP and CI-R-BDCP), which are potentially important disinfection byproducts that can contaminate the drinking water as well as the environment.

  16. The UV and Laser Aging for PMMA/BDK/Azo-dye Polymer Blend Cured by UV Light Beams

    NASA Astrophysics Data System (ADS)

    Ahmad, A. A.; Omari, A. M.

    2015-10-01

    A polymeric-based solution blend composed of Azo-dye methyl red (MR) doped with polymethelmethacrelate (PMMA) solution, in addition, to the BenzylDimethylKetal (BDK) photoinitiator was made with optimum molar ratios and deposited on glass substrate by spin coating technique. The samples were then exposed to UV light beams in order to assist the layers polymerization by the proper exposure process. The photo chemical reaction occurred during the UV light polymerization process induces photo refractive changes which were presented as a function of wavelength or photon energy. Two main strong absorption peaks were observed in the films at around 330 nm (3.75 eV) and 500 nm (2.48 eV) for different curing time periods. This phenomenon enhances the films usage for optical data storage media at these two wavelengths. Since the deposited films were then useful as based layers for Read/Write optical data storage media, they were then tested by UV or laser Read/Write beams independently. The optical properties of the films were investigated while exposed to each beam. Finally, their optical properties were investigated as a function of aging time in order to relate the temporary and/or permanent light-exposure effect on the films compared to their optical properties before the light exposure. The films show a low absorbance at 630 nm (1.97 eV) and high absorbance at 480 nm (2.58 eV). This fact makes it possible to record holographic gratings in the polymeric film upon light exposure. In all cases the optical properties were evaluated by using the very sensitive, non destructive surface testing spectroscopic ellipsometry technique. The films were characterized in the spectral range of 300 to 1000 nm using Lorentz oscillator model with one oscillator centred at 4.15 eV. This study has been supported by the SEM and EDAX results to investigate the effect of the UV and visible beams on their optical properties. The results of this research determined the proper conditions for

  17. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India.

    PubMed

    Faldu, P R; Kothari, V V; Kothari, C R; Rawal, C M; Domadia, K K; Patel, P A; Bhimani, H D; Raval, V H; Parmar, N R; Nathani, N M; Koringa, P G; Joshi, C G; Kothari, R K

    2014-02-06

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye.

  18. Draft Genome Sequence of Textile Azo Dye-Decolorizing and -Degrading Pseudomonas aeruginosa Strain PFK10, Isolated from the Common Effluent Treatment Plant of the Ankleshwar Industrial Area of Gujarat, India

    PubMed Central

    Faldu, P. R.; Kothari, V. V.; Kothari, C. R.; Rawal, C. M.; Domadia, K. K.; Patel, P. A.; Bhimani, H. D.; Raval, V. H.; Parmar, N. R.; Nathani, N. M.; Koringa, P. G.; Joshi, C. G.

    2014-01-01

    Here, we report the draft genome sequence of Pseudomonas aeruginosa strain PFK10, isolated from the common effluent treatment plant (CETP) of the Ankleshwar industrial area of Gujarat, India. The 6.04-Mb draft genome sequence of strain PFK10 provides information about the genes encoding enzymes that enable the strain to decolorize and degrade textile azo dye. PMID:24503984

  19. Synthesis, characterization and antimicrobial studies of 2-{(E)-[(2-hydroxy-5-methylphenyl)imino]methyl}-4-[(E)-phenyldiazenyl]phenol as a novel azo-azomethine dye

    NASA Astrophysics Data System (ADS)

    Köse, Muhammet; Kurtoglu, Nurcan; Gümüşsu, Özkan; Tutak, Mustafa; McKee, Vickie; Karakaş, Duran; Kurtoglu, Mukerrem

    2013-12-01

    A novel dye, 2-{(E)-[(2-hydroxy-5-methylphenyl)imino]methyl}-4-[(E)-phenyldiazenyl]phenol dye was synthesized by the condensation reaction of 2-hydroxy-5-[(E)-phenyldiazenyl]benzaldehyde with 2-amino-4-methylphenol in methanol. The title dye was characterized by its melting point, elemental analysis, FT-IR, 1H, 13C NMR and mass spectroscopic studies. Molecular structure of the title dye was determined by single crystal X-ray diffraction study. X-ray data showed that the dye crystallizes in the monoclinic space group P21/c with cell parameters a = 18.541(2) Å, b = 4.7091(5) Å, c = 20.586(2) Å, V = 1761.5(3) Å3 and Z = 4. The title dye adopts azo-enamine tautomer in the solid state. The molecules crystallises as dimers assembled by two molecules of methanol via intermolecular hydrogen bonding resulting in R64(18) hydrogen bonding motif. Additionally, there is an intramolecular keto-amine hydrogen bond (NH⋯O) with a distance of 2.6172(17) Å. Optimized structures of the three possible tautomers of the compound were obtained using B3LYP method with 6-311++G(d,p), 6-31G and 3-21G basis sets in the gas phase. Thermal properties of the prepared dye were examined by thermogravimetric analysis and results indicated that the framework of the dye is stable up to 172 °C. Furthermore, the pathogenic activities of the synthesized dye were tested in vitro against the sensitive organisms, Bacillus cereous (ATCC 33019) and Staphylococcus aureus (ATCC 25923) as gram positive bacteria, Escherichia coli (ATCC 11229), and Klebsiella pneumoniae (ATCC 13883) as gram negative bacteria and the results are discussed. The results indicated that the prepared dye had antibacterial activities against gram-positive bacteria (S. aureus and Bacillus cereuss), but it exhibited no activity against gram-negative bacteria (E. coli and K. pneumoniae).

  20. Microbial fuel cell operation using monoazo and diazo dyes as terminal electron acceptor for simultaneous decolourisation and bioelectricity generation.

    PubMed

    Oon, Yoong-Sin; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Oon, Yoong-Ling; Lehl, Harvinder Kaur; Thung, Wei-Eng; Nordin, Noradiba

    2017-03-05

    Monoazo and diazo dyes [New coccine (NC), Acid orange 7 (AO7), Reactive red 120 (RR120) and Reactive green 19 (RG19)] were employed as electron acceptors in the abiotic cathode of microbial fuel cell. The electrons and protons generated from microbial organic oxidation at the anode which were utilized for electrochemical azo dye reduction at the cathodic chamber was successfully demonstrated. When NC was employed as the electron acceptor, the chemical oxygen demand (COD) removal and dye decolourisation efficiencies obtained at the anodic and cathodic chamber were 73±3% and 95.1±1.1%, respectively. This study demonstrated that the decolourisation rates of monoazo dyes were ∼50% higher than diazo dyes. The maximum power density in relation to NC decolourisation was 20.64mW/m(2), corresponding to current density of 120.24mA/m(2). The decolourisation rate and power output of different azo dyes were in the order of NC>AO7>RR120>RG19. The findings revealed that the structure of dye influenced the decolourisation and power performance of MFC. Azo dye with electron-withdrawing group at para substituent to azo bond would draw electrons from azo bond; hence the azo dye became more electrophilic and more favourable for dye reduction.

  1. Photo-reductive decolorization of an azo dye by natural sphalerite: case study of a new type of visible light-sensitized photocatalyst.

    PubMed

    Li, Yan; Lu, Anhuai; Jin, Song; Wang, Changqiu

    2009-10-15

    Natural sphalerite, which represents a new class of mineral-based catalyst, was characterized and investigated for photo-reduction of an azo dye methyl orange (MO) under visible light. After 2h of visible light irradiation, a complete decolorization of the MO solution was achieved. The degradation rate was related to the pH conditions. Spectra from FT-IR analysis indicate an initial adsorption of MO to sphalerite via its sulfonate group. Further reduction of the adsorbed MO by sphalerite under light irradiation led to the destruction of the azo structure, as indicated by the results from UV-vis, FT-IR and ESI-MS analyses. The visible light-induced photocatalytic reductive activity of natural sphalerite was mainly attributed to the distribution of foreign metal atoms in its crystal lattice, which reduces the intrinsic bandgap of sphalerite and also broadens its spectra responding range. In addition, the high conduction band potential of natural sphalerite may also enhance the photo-reduction of MO.

  2. Preparation and Photovoltaic Properties of Dye Sensitized Solar Cells Using ZnO Nanorods Stacking Films on AZO Substrate as Photoanode.

    PubMed

    Xu, Yang; Wang, Xina; Liu, Rong; Wang, Hao

    2016-04-01

    Three-dimensional stacking of ZnO nanorods on conducting aluminum-doped ZnO (AZO) glass were studied as efficient photoanodes of dye sensitized solar cells (DSSCs). By changing hydrothermal growth time and cycle times, the thickness of ZnO nanorods stacking films varied from 30 µm to 64 µm, and its influence on the energetic conversion efficiency of the DSSCs based on the stacking films photoanodes was investigated. The loading density of N719 on the surface of ZnO nanorods was studied to increase the efficiency of the cells. Annealing experiments showed that the AZO substrates remained good conductors until heated above 350 °C. A photoelectric conversion efficiency as high as ~2.0% together with ISC of ~9.5 mA/cm2, VOC of ~0.5 V and FF of ~41.4% was achieved for the DSSC using 50 µm-thick film stacking by ZnO nanorods as photoanode and N719 as sensitizer under illumination of AM1.5G solar light (power density of 100 mW/cm2). A charge separation and transfer mechanism was proposed for the ZnO nanorods stacking electrode-based DSSCs.

  3. New 1,2,4-triazole-based azo-azomethine dye. Part III: Synthesis, characterization, thermal property, spectrophotometric and computational studies

    NASA Astrophysics Data System (ADS)

    Erfantalab, Malihe; Khanmohammadi, Hamid

    A new 1,2,4-triazole-based azo-azomethine compound, H2L, has been prepared by condensation reaction of 1-(3-formyl-4-hydroxyphenylazo)-4-ethylbenzene with prepared triazole-based diamine. The structure of H2L was characterized by using FT-IR, UV-Vis and 1H NMR spectroscopic methods as well as elemental analysis. Hard model chemometrics method has been used to determine the formation constants of zinc(II), copper(II), nickel(II) and cobalt(II) complexes of H2L in DMSO by UV-Vis spectrophotometric method. Solvatochromic behavior of the dye has been also investigated in some organic solvents with different polarities. Thermal properties of the prepared dye was examined by thermogravimetric analysis. Results indicated that the framework of the dye was stable up to 245 °C. Furthermore,1H chemical shifts and UV-Vis of H2L were studied by the gauge independent atomic orbital (GIAO), continuous set of gauge transformations (CSGT) and time-dependent density functional theory (TD-DFT) methods respectively at the level of density functional theory using B3LYP/6-311+G(d) basis sets in DMSO. The computational data are in reasonably good agreement with the experimental data.

  4. Influence of phase stabilization and perovskite vanadate oxygen vacancies of the BINIVOX catalyst on photocatalytic degradation of azo dye under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Al-Areqi, Niyazi A. S.; Al-Kamali, Ahmed S. N.; Ghaleb, Kh. A. S.; Al-Alas, Ahlam; Al-Mureish, Khalid

    2014-02-01

    A layered Aurivillius-perovskite-type BINIVOX system with the general formula ? was developed as a novel photocatalyst for degradation of organic dyes. A series of the BINIVOX.x catalysts in the compositional range 0≤x≤0.20 were successfully synthesized by the standard solid-state reaction and characterized using X-ray powder diffraction, differential thermal analysis, UV-vis diffuse reflectance spectroscopy and Brunauer-Emmett-Teller BET surface area. Then, the photocatalytic activities of prepared catalysts were investigated for the first time through the degradation of a new azo dye named sodium 4-[(E)-(4,5-dimethyl-1H-pyrazolo [3,4-c] pyridazin-3-yl) diazenyl] naphthalen-1-olate and denoted as 4-SPPN in aqueous solution under visible light irradiation. Adsorption efficiency and photocatalytic activity of BINIVOX.x catalysts were correlated well with the variation in phase crystal structures stabilized at room temperature as a function of composition. The stabilized γ‧-BINIVOX phases in the tetragonal crystal system with space group I4/m mm exhibited the best photocatalytic performance which can be attributed to their higher specific surface area, narrower band-gap energy and higher oxygen-vacancy concentration in the perovskite vanadate layers. In addition, the possible photocatalytic degradation mechanism of aqueous 4-SPPN dye was proposed under visible light irradiation.

  5. Degradation of Amaranth azo dye in water by heterogeneous photo-Fenton process using FeWO4 catalyst prepared by microwave irradiation.

    PubMed

    da Cruz Severo, Eric; Anchieta, Chayene Gonçalves; Foletto, Vitória Segabinazzi; Kuhn, Raquel Cristine; Collazzo, Gabriela Carvalho; Mazutti, Marcio Antonio; Foletto, Edson Luiz

    2016-01-01

    FeWO4 particles were synthesized by a simple, rapid and facile microwave technique and their catalytic properties in heterogeneous photo-Fenton reaction were evaluated. This material was employed in the degradation of Amaranth azo dye. Individual and interactive effects of operational parameters such as pH, dye concentration and H2O2 dosage on the decolorization efficiency of Amaranth dye were evaluated by 2(3) central composite design. According to characterization techniques, a porous material and a well-crystallized phase of FeWO4 oxide were obtained. Regarding the photo-Fenton reaction assays, up to 97% color and 58% organic carbon removal were achieved in the best experimental conditions. In addition, the photo-Fenton process maintained treatment efficiency over five catalyst reuse cycles to indicate the durability of the FeWO4 catalyst. In summary, the results reveal that the synthesized FeWO4 material is a promising catalyst for wastewater treatment by heterogeneous photo-Fenton process.

  6. Preparation and photocatalytic performance of Fe (III)-amidoximated PAN fiber complex for oxidative degradation of azo dye under visible light irradiation.

    PubMed

    Dong, Yongchun; Han, Zhenbang; Liu, Chunyan; Du, Fang

    2010-04-15

    Polyacrylonitrile (PAN) fiber was modified with hydroxylamine hydrochloride to introduce amidoxime groups onto the fiber surface. These amidoxime groups were used to react with Fe (III) ions to prepare Fe (III)-amidoximated PAN fiber complex, which was characterized using SEM, XRD, FTIR, XPS, DMA, and DRS respectively. Then the photocatalytic activity of Fe-AO-PAN was evaluated in the degradation of a typical azo dye, C. I. Reactive Red 195 in the presence of H(2)O(2) under visible light irradiation. Moreover, the effect of the Fe content of Fe-AO-PAN on dye degradation was also investigated. The results indicated that Fe (III) ions can crosslink between the modified PAN fiber chains by the coordination of Fe (III) ions with the amino nitrogen atoms and hydroxyl oxygen atoms of the amidoximation groups to form Fe (III)-amidoximated PAN fiber complex, and the Fe content of which is mainly determined by Fe (III) ions and amidoximation groups. Fe (III)-amidoximated PAN fiber complex is found to be activated in the visible light region. Moreover, Fe (III)-amidoximated PAN fiber complex shows the catalytic activity for dye degradation by H(2)O(2) at pH=6.0 in the dark, and can be significantly enhanced by increasing light irradiation and Fe content, therefore, it can be used as a new heterogeneous Fenton photocatalyst for the effective decomposition of the dye in water. In addition, ESR spectra confirm that Fe (III)-amidoximated PAN fiber complex can generate more OH radicals from H(2)O(2) under visible light irradiation, leading to dye degradation. A possible mechanism of photocatalysis is proposed.

  7. Performance and microbial diversity of microbial fuel cells coupled with different cathode types during simultaneous azo dye decolorization and electricity generation.

    PubMed

    Hou, Bin; Hu, Yongyou; Sun, Jian

    2012-05-01

    To study the effect of cathode type on performance and microbial diversity of the MFC, aerobic biocathode and air-cathode were incorporated into microbial fuel cells (MFCs) which were explored for simultaneous azo dye decolorization and electricity generation. The electrochemical impedance spectroscopy (EIS) results demonstrated that the catalytic activity of the microorganisms on the biocathode surface was comparable with that of the platinum coated on the air-cathode. The power density achieved by using biocathode was lower than air-cathode, but the biocathode could greatly improve the Congo red decolorization rate. By using the biocathode, 96.4% decolorization of Congo red was obtained within 29 h, whereas, about 107 h was required to achieve the same decolorization efficiency with the air-cathode. 16S rRNA sequencing analysis demonstrated a phylogenetic diversity in the communities of the anode biofilm and showed clear differences between the anode-attached populations in the MFCs with a different cathode type.

  8. Highly unsaturated fatty acid might act as an antioxidant in emulsion system oxidized by azo compound.

    PubMed

    Gotoh, Naohiro; Noguchi, Yosuke; Ishihara, Akiko; Yamaguchi, Kaita; Mizobe, Hoyo; Nagai, Toshiharu; Otake, Ikuko; Ichioka, Kenji; Wada, Shun

    2010-01-01

    Now it is recognized that DHA is oxidatively stable fatty acid compared with linoleic acid (LA) in emulsified system, although DHA is oxidatively unstable in a bulk system. In fact, an emulsified mixture of DHA and LA behaves as in a bulk system, namely the oxidative stability of DHA becomes lower than that of LA. Therefore, in this study, tridocosahexaenoate (DDD) and glycerol trilinoleate (LLL) were separately emulsified using TritonX-100 as an emulsifier and DDD emulsion was mixed with the oxidizing LLL emulsion using a water-soluble radical initiator, 2,2'-azobis(2-aminopropane) dihydrochloride. As a result, DHA suppressed the oxidation of LA, while DHA was not significantly oxidized. This suppression ability was examined using glycerol trieicosapentaenoate, glycerol trilinolenate, or glycerol trioleate instead of DDD and it was found that this activity was increased with the increasing number of double bonds in the structure. Furthermore, the same type of experiment was carried out using a lipid-soluble radical initiator, 2,2'-azobisisobutyronitrile and the similar result was obtained. These results indicated that a highly polyunsaturated fatty acid might act as an antioxidant in an emulsion system oxidized by an azo compound.

  9. Degradation of a textile reactive azo dye by a combined biological-photocatalytic process: Candida tropicalis Jks2 -Tio2/Uv

    PubMed Central

    2012-01-01

    In the present study, the decolorization and degradation of Reactive Black 5 (RB5) azo dye was investigated by biological, photocatalytic (UV/TiO2) and combined processes. Application of Candida tropicalis JKS2 in treatment of the synthetic medium containing RB5 indicated complete decolorization of the dye with 200 mg/L in less than 24 h. Degradation of the aromatic rings, resulting from the destruction of the dye, did not occur during the biological treatment. Mineralization of 50 mg/L RB5 solution was obtained after 80 min by photocatalytic process (in presence of 0.2 g/L TiO2). COD (chemical oxygen demand) was not detectable after complete decolorization of 50 mg/L RB5 solution. However, photocatalytic process was not effective in the removal of the dye at high concentrations (≥200 mg/L). With 200 mg/L concentration, 74.9% of decolorization was achieved after 4 h illumination under photocatalytic process and the absorbance peak in UV region (attributed to aromatic rings) was not completely removed. A two-step treatment process, namely, biological treatment by yeast followed by photocatalytic degradation, was also assessed. In the combined process (with 200 mg/L RB5), absorbance peak in UV region significantly disappeared after 2 h illumination and about 60% COD removal was achieved in the biological step. It is suggested that the combined process is more effective than the biological and photocatalytic treatments in the remediation of aromatic rings. PMID:23369285

  10. Study of the release of a microencapsulated acid dye in polyamide dyeing using mixed cationic liposomes.

    PubMed

    de Sousa, Isabel S C; Castanheira, Elisabete M S; Rocha Gomes, Jaime I N; Real Oliveira, M Elisabete C D

    2011-06-01

    The main objective of this work was to increase the retarding effect of the acid dye Telon(®) Blue RR (C.I. Acid Blue 62; DyStar, Frankfurt, Germany) release on polyamide fibres dyeing by encapsulation of the dye in liposomes as an alternative to synthetic auxiliaries, in order to reduce effluent pollution. The retarding effect achieved with the use of mixed cationic liposomes of dioctadecyldimethylammonium bromide (DODAB)/soybean lecithin (containing a 10% molar fraction of DODAB) was better in comparison with either pure soybean lecithin liposomes or synthetic auxiliaries. The retarding effect of liposomes on the dye release was analysed through changes in the absorption and fluorescence spectra of the acid dye at different conditions. The effect of temperature (in the range of 25 °C - 70 °C) on the spectroscopic behaviour of the dye in the absence and in presence of polyamide was also studied, in order to simulate the dyeing conditions. Exhaustion curves obtained in dyeing experiments showed that, below 45 °C, the retarding effect of the mixed liposomes (lecithin/DODAB (9:1)) was similar to that of the auxiliaries, but better than the one of pure lecithin liposomes. At higher temperatures (above 45 °C), the system lecithin/DODAB presents a better performance, achieving a higher final exhaustion level when compared with the commercial leveling agent without losing the smoothing effect of lecithin.

  11. Adsorption mechanism and kinetics of azo dye chemicals on oxide nanotubes: a case study using porous CeO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Wu, Junshu; Wang, Jinshu; Du, Yucheng; Li, Hongyi; Jia, Xinjian

    2016-07-01

    Metal oxide nanotubes are believed to be promising materials with adsorption functionality for water purification due to their synergistic effect of the overall microscale morphology for easy separation and nanoscale surface characters providing enough surface active absorption sites. This work shows the synthesis of uniform hierarchical porous CeO2 nanotubes via nanowire-directed templating method and describes the adsorption behavior of CeO2 nanotubes for a typical azo dye Congo red which has resistance to oxidation and decoloration in natural conditions. Fourier transform infrared spectroscopy spectra provided the evidence that Congo red was successfully coated on the surface of CeO2 nanotubes by both bidentate-type bridge link of Ce4+ cations from sulfonate SO3 - groups and the electrostatic attraction between the protonated surface generated by oxygen vacancies and dissociated sulfonate groups. The adsorption kinetic data fitted well to the pseudo-second-order kinetic equation, whereas the Langmuir isotherm equation exhibited better correlation with the experimental data. The calculated maximum adsorption capacity from the isothermal model was 362.32 mg/g. In addition, the prepared CeO2 nanotubes exhibited good recyclability and reusability as highly efficient adsorbents for Congo red removal after regeneration. These favorable performances enable the obtained CeO2 nanotubes to be promising materials for dye removal from aqueous solution.

  12. Enhanced accumulation and visible light-assisted degradation of azo dyes in poly(allylamine hydrochloride)-modified mesoporous silica spheres

    SciTech Connect

    Tao Xia Liu Bing; Hou Qian; Xu Hui; Chen Jianfeng

    2009-02-04

    A new route for the economic and efficient treatment of azo dye pollutants is reported, in which surface-modified organic-inorganic hybrid mesoporous silica (MS) spheres were chosen as microreactors for the accumulation and subsequent photodegradation of pollutants in defined regions. The surface-modified silica materials were prepared by anchoring the polycationic species such as poly(allylamine hydrochloride) on MS spheres via a simple wet impregnation method. The as-synthesized spheres with well-defined porous structures exhibited 15 times of accumulating capacity for orange II and Congo red compared to that of the pure MS spheres. Diffuse reflectance UV-vis spectroscopy and confocal laser scanning microscopy demonstrated that the accumulated orange II and CR in defined MS spheres were rapidly degraded in the presence of Fenton reagent under visible radiation. Kinetics analysis in recycling degradation showed that the as-synthesized materials might be utilized as environment-friendly preconcentrators/microreactors for the remediation of dye wastewater.

  13. New self-assembled material based on Ru nanoparticles and 4-sulfocalix[4]arene as an efficient and recyclable catalyst for reduction of brilliant yellow azo dye in water: a new model catalytic reaction

    NASA Astrophysics Data System (ADS)

    Rambabu, Darsi; Pradeep, Chullikkattil P.; Dhir, Abhimanew

    2016-12-01

    New self-assembled material ( Ru@SC) with ruthenium nanoparticles (Ru NPs) and 4-sulfocalix[4]arene (SC) is synthesized in water at room temperature. Ru@SC is characterized by thermal gravimetric analysis, FT-IR, powder x-ray diffraction, TEM and SEM analysis. The size of Ru nanoparticles in the self-assembly is approximately 5 nm. The self-assembled material Ru@SC shows an efficient catalytic reduction of toxic `brilliant yellow' (BY) azo dye. The reduced amine products were successfully separated and confirmed by single-crystal XRD, NMR and UV-Vis spectroscopy. Ru@SC showed a better catalytic activity in comparison with commercial catalysts Ru/C (ruthenium on charcoal 5 %) and Pd/C (palladium on charcoal 5 and 10 %). The catalyst also showed a promising recyclability and heterogeneous nature as a catalyst for reduction of `BY' azo dye.

  14. Production of polyhydroxyhexadecanoic acid by using waste biomass of Sphingobacterium sp. ATM generated after degradation of textile dye Direct Red 5B.

    PubMed

    Tamboli, Dhawal P; Kagalkar, Anuradha N; Jadhav, Mital U; Jadhav, Jyoti P; Govindwar, Sanjay P

    2010-04-01

    The degradation of textile effluent using microorganisms has been studied extensively, but disposal of generated biomass after dye degradation is a serious problem. The isolated Sphingobacterium sp. ATM was found to decolorize dye Direct Red 5B (DR5B) and simultaneously it produced polyhydroxyhexadecanoic acid (PHD). The organism decolorized DR5B at 500mgl(-1) concentration within 24h of dye addition and gave optimum production of PHD. The medium contains carbon source as a molasses which was found to be more significant within all carbon sources used. The Nuclear Magnetic Resonance spectroscopy (NMR), Fourier Transform Infrared spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) characterization of polyhydroxyalkanoates obtained revealed the compound as a polyhydroxyhexadecanoic acid. The activity of PHA synthase was found more at 24h after dye addition. The enzymes responsible for dye degradation include veratrol oxidase, laccase, DCIP (2,6-dichlorophenol-indophenol) reductase, riboflavin reductase and azo reductase was found to be induced during decolorization process. The FTIR analysis of samples before and after decolorization of dye confirmed the biotransformation of DR5B. The GC-MS analysis of product obtained led to the identification of two metabolites after biotransformation of dye as p-amino benzenesulfonic acid and naphthalene-1-ol.

  15. Accelerated azo dye degradation and concurrent hydrogen production in the single-chamber photocatalytic microbial electrolysis cell.

    PubMed

    Hou, Yanping; Zhang, Renduo; Yu, Zebin; Huang, Lirong; Liu, Yuxin; Zhou, Zili

    2017-01-01

    The single-chamber microbial electrolysis cell constructed with a TiO2-coated photocathode, termed photocatalytic microbial electrolysis cell (PMEC), was developed to accelerate methyl orange (MO) degradation and concurrent hydrogen (H2) recovery under UV irradiation. Results showed that faster MO decolorization rates were achieved from the PMEC compared with those without UV irradiation or with open circuit. With increase of MO concentrations (acetate as co-substrate) from 50 to 300mg/L at an applied voltage of 0.8V, decolorization efficiencies decreased from 98% to 76% within 12h, and cyclic H2 production declined from 113 to 68mL. As the possible mechanism of MO degradation, bioelectrochemical reduction, co-metabolism reduction, and photocatalysis were involved; and degradation intermediates (mainly sulfanilic acid and N,N-dimethylaniline) were further degraded by OH generated from photocatalysis. This makes MO mineralization be possible in the single-chamber PMEC. Hence, the PMEC is a promising system for dyeing wastewater treatment and simultaneous H2 production.

  16. Third-Order Nonlinear Optical Property of POLY(HEXA-2,4-DIYNYLENE-1,6-DIOXYDICINNAMATE) Containing a Polar Azo Dye, Determined by Z-Scan Technique

    NASA Astrophysics Data System (ADS)

    Ortega, Alejandra; Perez-Martinez, Ana Laura; Ogawa, Takeshi; Smith, Francis; Walser, Ardie; Dorsinville, Roger

    A highly-conjugated polar dye with three aromatic rings connected with azo groups was prepared and it was incorporated in polycinnamate. It showed a third-order nonlinear susceptibility of 8 × 10-10 esu determined by a Z-scan technique. The unpoled and poled films show the same susceptibility indicating the polymer film could not be poled. The open aperture Z-scan showed negligible two-photon absorption at 1064 nm.

  17. Photo-electrochemical studies of chemically deposited nanocrystalline meso-porous n-type TiO2 thin films for dye-sensitized solar cell (DSSC) using simple synthesized azo dye

    NASA Astrophysics Data System (ADS)

    Ezema, C. G.; Nwanya, A. C.; Ezema, B. E.; Patil, B. H.; Bulakhe, R. N.; Ukoha, P. O.; Lokhande, C. D.; Maaza, Malik; Ezema, Fabian I.

    2016-04-01

    Nanocrystalline titanium dioxide (TiO2) thin films were deposited by successive ionic layer adsorption and reaction method onto fluorine doped tin oxide coated glass substrate at room temperature (300 K). Titanium trichloride and sodium hydroxide were used as cationic and anionic sources, respectively. The as-deposited and annealed films were characterized for structural, morphological, optical, electrical and wettability properties. The photoelectrochemical study of TiO2 sensitized with a laboratory synthesized organic dye (azo) was evaluated in the polyiodide electrolyte at 40 mW cm-2 light illumination intensity. The photovoltaic characteristics show a fill factor of 0.24 and solar conversion efficiency value of 0.032 % for a TiO2 thickness of 0.96 µm as compared to efficiency of 0.014 % for rose Bengal of the same thickness.

  18. Differential fate of metabolism of a sulfonated azo dye Remazol Orange 3R by plants Aster amellus Linn., Glandularia pulchella (Sweet) Tronc. and their consortium.

    PubMed

    Kabra, Akhil N; Khandare, Rahul V; Waghmode, Tatoba R; Govindwar, Sanjay P

    2011-06-15

    Plant consortium-AG of Aster amellus Linn. and Glandularia pulchella (Sweet) Tronc. showed complete decolorization of a dye Remazol Orange 3R in 36 h, while individually A. amellus and G. pulchella took 72 and 96 h respectively. Individually A. amellus showed induction in the activities of enzymes veratryl alcohol oxidase and DCIP reductase after degradation of the dye while G. pulchella showed induction of laccase and tyrosinase, indicating their involvement in the dye metabolism. Consortium-AG showed induction in the activities of lignin peroxidase, veratryl alcohol oxidase, laccase, tyrosinase and DCIP reductase. Two different sets of induced enzymes from A. amellus and G. pulchella work together in consortium-AG resulting in faster degradation of the dye. The degradation of the dye into different metabolites was confirmed using High Performance Liquid Chromatography and Fourier Transform Infra Red Spectroscopy. Gas Chromatography Mass Spectroscopy analysis identified four metabolites of dye degradation by A. amellus as acetamide, benzene, naphthalene and 3-diazenylnaphthalene-2-sulfonic acid, four metabolites by G. pulchella as acetamide, 3-diazenyl-4-hydroxynaphthalene-2-sulfonic acid, naphthalen-1-ol and (ethylsulfonyl)benzene, while two metabolites by consortium-AG as 2-(phenylsulfonyl)ethanol and N-(naphthalen-2-yl)acetamide. The non-toxic nature of the metabolites of Remazol Orange 3R degradation was revealed by phytotoxicity studies.

  19. Biphasic reduction model for predicting the impacts of dye-bath constituents on the reduction of tris-azo dye Direct Green-1 by zero valent iron (Fe(0)).

    PubMed

    Kumar, Raja; Sinha, Alok

    2017-02-01

    Influence of common dye-bath additives, namely sodium chloride, ammonium sulphate, urea, acetic acid and citric acid, on the reductive decolouration of Direct Green 1 dye in the presence of Fe(0) was investigated. Organic acids improved dye reduction by augmenting Fe(0) corrosion, with acetic acid performing better than citric acid. NaCl enhanced the reduction rate by its 'salting out' effect on the bulk solution and by Cl(-) anion-mediated pitting corrosion of iron surface. (NH4)2SO4 induced 'salting out' effect accompanied by enhanced iron corrosion by SO4(2-) anion and buffering effect of NH4(+) improved the reduction rates. However, at 2g/L (NH4)2SO4 concentration, complexating of SO4(2-) with iron oxides decreased Fe(0) reactivity. Urea severely compromised the reduction reaction, onus to its chaotropic and 'salting in' effect in solution, and due to it masking the Fe(0) surface. Decolouration obeyed biphasic reduction kinetics (R(2)>0.993 in all the cases) exhibiting an initial rapid phase, when more than 95% dye reduction was observed, preceding a tedious phase. Maximum rapid phase reduction rate of 0.955/min was observed at pH2 in the co-presence of all dye-bath constituents. The developed biphasic model reckoned the influence of each dye-bath additive on decolouration and simulated well with the experimental data obtained at pH2.

  20. Intracellular azo decolorization is coupled with aerobic respiration by a Klebsiella oxytoca strain.

    PubMed

    Yu, Lei; Zhang, Xiao-Yu; Xie, Tian; Hu, Jin-Mei; Wang, Shi; Li, Wen-Wei

    2015-03-01

    Reduction of azo dye methyl red coupled with aerobic respiration by growing cultures of Klebsiella oxytoca GS-4-08 was investigated. In liquid media containing dye and 0.6 % glucose in a mineral salts base, 100 mg l(-1) of the dye are completely removed in 3 h under shaking conditions. The dye cannot be aerobically decolorized by strain GS-4-08 without extra carbon sources, indicating a co-metabolism process. Higher initial dye concentration prolonged the lag phase of the cell growth, but final cell concentrations of each batches reached a same level with range from 6.3 to 7.6 mg l(-1) after the dye adaption period. This strain showed stronger dye tolerance and decolorization ability than many reported strains. Furthermore, a new intracellular oxygen-insensitive azoreductase was isolated from this strain, and the specific activity of enzyme was 0.846 and 0.633 U mg(-1) protein in the presence of NADH and NADPH, respectively. N,N dimethyl-p-phenylenediamine and anthranilic acid were stoichiometrically released from MR dye, indicating the breakage of azo bonds accounts for the intracellular decolorization. Combining the characteristics of azoreductase, the stoichiometry of EMP, and TCA cycle, the electron transfer chain theory of aerobic respiration, and the possible mechanism of aerobic respiration coupled with azo reduction by K. oxytoca GS-4-08 are proposed. This study is expected to provide a sound theoretical basis for the development of the K. oxytoca strain in aerobic process for azo dye containing wastewaters.

  1. Torsionally Responsive C[subscript 3]-Symmetric Azo Dyes: Azo−Hydrazone Tautomerism, Conformational Switching, and Application for Chemical Sensing

    SciTech Connect

    Lee, Ho Yong; Song, Xinli; Park, Hyunsoo; Baik, Mu-Hyun; Lee, Dongwhan

    2010-12-07

    An efficient triple azo coupling reaction between anilines and phloroglucinol furnished a series of C{sub 3}-symmetric molecules 7-9 supporting multiple conjugation pathways that converge at the molecular core. A combination of {sup 1}H/{sup 13}C NMR spectroscopy, X-ray crystallography, and density functional theory computational studies provided a coherent picture of the [n,{pi}]-conjugated molecular core, which is best described as the tris(hydrazone) [rather than tris(azo)] tautomer stabilized by resonance-assisted hydrogen bonding. For a homologous series of compounds, an increase in the torsional angles between the planar molecular core and the peripheral aryl groups results in a systematic blue shift in the low-energy electronic transitions (7, 523 nm; 8, 505 nm; 9, 445 nm in CHCl{sub 3}) that qualitatively correlates with the shrinkage of effective conjugation through structural distortion. Similar spectral shifts could also be induced by amine substrates that interact with the intramolecular hydrogen-bonding network to trigger bond-twisting motions. Specifically, a brief exposure of a thin film of 7 to vapor samples of butyl-, hexyl-, diethyl-, and diisopropylamine resulted in a rapid and reversible color change from pink to dark-orange. Under similar conditions, however, triethylamine did not elicit any detectable color change, despite the fact that it has a significantly higher vapor pressure than n-hexylamine. These findings implicate that the hydrogen-bonding donor ability is a key requirement for the binding-induced conformational switching, which allows for direct naked-eye detection of volatile amines under ambient conditions.

  2. Hydroxyl radical concentration profile in photo-Fenton oxidation process: generation and consumption of hydroxyl radicals during the discoloration of azo-dye Orange II.

    PubMed

    Maezono, Takuya; Tokumura, Masahiro; Sekine, Makoto; Kawase, Yoshinori

    2011-03-01

    Dynamic behaviors of hydroxyl (OH) radical generation and consumption in photo-Fenton oxidation process were investigated by measuring OH radical concentration during the discoloration of azo-dye Orange II. The effects of operating parameters for photo-Fenton discoloration, i.e. dosages of H(2)O(2) and Fe, initial dye concentration, solution pH and UV irradiation, on the generation and consumption of OH radicals playing the main role in advanced oxidation processes were extensively studied. The scavenger probe or trapping technique in which coumarin is scavenger of OH radical was applied to estimate OH radical concentration in the photoreactor during the photo-Fenton discoloration process. The OH radical generation was enhanced with increasing the dosages of Fenton regents, H(2)O(2) and Fe. At the initial stage of photo-Fenton discoloration of Orange II, the OH radical concentration rapidly increased (Phase-I) and the OH radical concentration decreased after reaching of OH radical concentration at maximum value (Phase-II). The decrease in OH radical concentration started when the complete discoloration of Orange II was nearly achieved and the H(2)O(2) concentration became rather low. The dynamic behavior of OH radical concentration during the discoloration of Orange II was found to be strongly linked with the change in H(2)O(2) concentration. The generation of OH radical was maximum at solution pH of 3.0 and decreased with an increase of solution pH. The OH radical generation rate in the Fenton Process was rather slower than that in the photo-Fenton process.

  3. Optimization of working cathode position in sleeve-type bioelectrochemical system with inner chamber/outer chamber for azo dye treatment.

    PubMed

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2015-12-01

    In this study, the optimization of working cathode position in sleeve-type bioelectrochemical system (BES) was evaluated with inner/outer chamber for azo dye decolorization. Results showed that the working position in outer chamber performed better with decolorization efficiencies of 97.8 ± 2.1% (7h) and 94.0 ± 2.3% (16 h) than that in inner chamber as the volume ratio Vcathode:Vanode=1:1 and 3:1, respectively. The current and electrochemical impedance spectroscopy (EIS) analysis indicated that the proton/electron transfer and anolyte diffusion could be improved using outer chamber as working position. The decolorization with increased volume ratio could be further improved through the strategy of increasing substrate concentration, which would provide enough electrons and decrease diffusion resistance, further improving the whole performance with increased outer cathode volume. It has the great potential in sleeve-type configuration application and would create more challenges for process optimization and maintenance.

  4. Liquid-phase non-thermal plasma-prepared N-doped TiO(2) for azo dye degradation with the catalyst separation system by ceramic membranes.

    PubMed

    Cheng, Hsu-Hui; Chen, Shiao-Shing; Cheng, Yi-Wen; Tseng, Wei-Lun; Wang, Yi-Hui

    2010-01-01

    This study strived to improve the photocatalytic activity by using liquid-phase non-thermal plasma (LPNTP) technology for preparing N-doping TiO(2) as well as to separate/recover the N-dope TiO(2) particles by using ceramic ultrafiltration membrane process. The yellow color N-doped TiO(2) photocatalysts, obtained through the LPNTP process, were characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysis (ESCA). The UV-Vis spectrum of N-doped TiO(2) showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectra showed that the peak positions and the crystal structure remained unchanged as anatase after plasma-treating at 13.5 W for 40 min. The photocatalytic activity of N-doped TiO(2) was evaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours in a continuous-flow photocatalytic system. For membrane separation/recover system, the recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min, and the result indicated that the photocatalyst was able to be separated/recovered completely.

  5. Catalytic ozonation of Orange-G through highly interactive contributions of hematite and SBA-16 - To better understand azo-dye oxidation in nature.

    PubMed

    Larouk, Safa; Ouargli, Rachida; Shahidi, Dariush; Olhund, Leanne; Shiao, Tze Chieh; Chergui, Nacira; Sehili, Tahar; Roy, René; Azzouz, Abdelkrim

    2017-02-01

    Hematite-SBA-16 mixture (HS) exhibited high catalytic activity in Orange-G (OG) ozonation in water. Total OG discoloration was achieved in half the time required with hematite or SBA-16 alone, all UV-Vis bands disappeared in less than 2 min. Liquid chromatography- Mass spectrometry (LC-MS) revealed that OG ozonation triggers via both hydroxylation and desulfonation of the aromatic rings into specific intermediates. Prolonged ozonation in the presence of hematite and SBA-16 alone resulted in different distributions of common derivatives. The latter were not detected after 25 min ozonation with HS. Stochastic modeling of the evolution in time of the UV-Vis bands of OG revealed strong binary interaction between the initial pH and catalyst concentration. This was explained in terms of reciprocal contributions of: i. the catalytic properties of hematite in spite of its low porosity; ii. the high specific surface area of SBA-16 for adsorption and surface reaction notwithstanding its low intrinsic catalytic activity. The weak basicity of SBA-16 surface seems to play a key-role in adsorption. These findings are of great interest for envisaging flexible oxidative treatments, where Fe(3+) containing soils or mixtures of sand and rust may also act as catalyst for total mineralization of various azo-dyes, regardless to their structures.

  6. [Characterization of cases contravening of regulations regarding primary aromatic amines originating from azo dyes in commercial textile products and leather products in European Union].

    PubMed

    Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

    2013-01-01

    Contraventions of regulations regarding primary aromatic amines (PAAs) originating from azo dyes in commercial textile products and leather products in European Union (EU), notified in the period between 2006 and 2012 were collected from the Rapid Alert System for non-food consumer products (RAPEX), were characterized. Various types of products (clothes, footwear, bedding, etc.) and their raw materials (cotton, silk, viscose, leather, etc.) were reported to have contravened the regulations. The contravention frequencies for products made in China and India were higher than those for other countries. Ten percentage of the country in which the reported products were produced was unknown. The notification frequencies for benzidine and 4-aminoazobenzene were higher than those for other PAAs. Contravention of regulations regarding benzidine, 4-aminoazobenzene, and 3,3'-dimethoxybenzidine were notified every year. Contraventions of regulations regarding five PAAs--classified as IARC group 1--were notified one or several times. Since the scale of the survey conducted in Japan were small compared with RAPEX, it is necessary that many kinds and number of products should be surveyed in Japan. In addition, it is also necessary to pay attention to 4-aminoazobenzene, while it has not been detected in the previous studies conducted in Japan.

  7. Effect of food azo dyes tartrazine and carmoisine on biochemical parameters related to renal, hepatic function and oxidative stress biomarkers in young male rats.

    PubMed

    Amin, K A; Abdel Hameid, H; Abd Elsttar, A H

    2010-10-01

    Tartrazine and carmoisine are an organic azo dyes widely used in food products, drugs and cosmetics. The present study conducted to evaluate the toxic effect of these coloring food additives; on renal, hepatic function, lipid profile, blood glucose, body-weight gain and biomarkers of oxidative stress in tissue. Tartrazine and carmoisine were administered orally in two doses, one low and the other high dose for 30 days followed by serum and tissue sample collection for determination of ALT, AST, ALP, urea, creatinine, total protein, albumin, lipid profile, fasting blood glucose in serum and estimation of GSH, catalase, SOD and MDA in liver tissue in male albino rat. Our data showed a significant increase in ALT, AST, ALP, urea, creatinine total protein and albumin in serum of rats dosed with tartrazine and carmoisine compared to control rats and these significant change were more apparent in high doses than low, GSH, SOD and Catalase were decreased and MDA increased in tissue homogenate in rats consumed high tartrazine and both doses of carmoisine. We concluded that tartrazine and carmoisine affect adversely and alter biochemical markers in vital organs e.g. liver and kidney not only at higher doses but also at low doses.

  8. Multi-scale biomarker evaluation of the toxicity of a commercial azo dye (Disperse Red 1) in an animal model, the freshwater cnidarian Hydra attenuata.

    PubMed

    de Jong, Laetitia; Pech, Nicolas; de Aragão Umbuzeiro, Gisela; Moreau, Xavier

    2016-06-01

    Acute (24 h, 48 h, 72 h) and chronic (7 days) tests have been performed to evaluate the effects of the commercial azo dye Disperse Red 1 (DR1) using various biomarkers in the freshwater invertebrate Hydra attenuata. Morphological changes have been selected to calculate ecotoxicological thresholds for sublethal and lethal DR1 concentrations. A multinomial logistic model showed that the probability of each morphological stage occurrence was function of concentration, time and interaction between both. Results of oxidative balance parameter measurements (72 h and 7 days) suggest that polyps set up defense mechanisms to limit lipid peroxidation caused by DR1. DR1 exposure at hormetic concentrations induces increase of asexual reproductive rates. This result suggests (1) an impact on the fitness-related phenotypical traits and (2) trade-offs between reproduction and maintenance to allow the population to survive harsher conditions. Changes in serotonin immuno-labeling in polyps showing alterations in feeding behavior suggest that chronic DR1 exposure impaired neuronal processes related to ingesting behavior in H. attenuata. This ecotoxicity study sheds light on the possible serotonin function in Hydra model and reports for the first time that serotonin could play a significant role in feeding behavior. This study used a multi-scale biomarker approach investigating biochemical, morphological, reproductive and behavioral endpoints in Hydra attenuata. This organism is proposed for a pertinent animal model to assess ecotoxicological impact of pollutant mixtures in freshwater environment.

  9. Novel determination of nabumetone, a cox-2 inhibitor precursor via its 4-carboxyl-2,6-dinitrobenzene diazonium (CDNBD) derived AZO dye.

    PubMed

    Adegoke, A O; Idowu, S O; Olaniyi, A A

    2007-09-01

    A novel colorimetric determination ofnabumetone in tablets has been developed. The assay is based on chemical derivatization (aromatic ring derivatization technique) using newly developed 4-carboxyl-2,6-dinitrobenzene diazonium (CDNBD) ion as the chromogenic derivatizing reagent and resultant formation of azo dye.Optimization studies established an optimal reaction time of 10 minutes at 30 degrees C after mixing the drug/reagent mixture in a vortex mixer for 10 sec. A new absorption maximum (ë(max)) was found at 470 nm, which was selected as analytical wavelength. The assays were linear over 1-6 microg/ml of nabumetone and the optimal reaction required a 2:1 reagent/drug stoichiometric ratio. The developed method has a low limit of detection of 0.39 microg/ml, and is reproducible (1.81% RSD). It has been applied successfully to the assay of nabumetone tablets and is of equivalent accuracy (p > 0.05) with the official (B.P) HPLC method. The new method is simple, has the main advantage of employing a more affordable instrumentation and could find application in routine in-process quality control of nabumetone tablets.

  10. Comparative studies of operational parameters of degradation of azo dyes in visible light by highly efficient WOx/TiO2 photocatalyst.

    PubMed

    Sajjad, Ahmed Khan Leghari; Shamaila, Sajjad; Tian, Baozhu; Chen, Feng; Zhang, Jinlong

    2010-05-15

    The multidimensional aspects of the photocatalytic activity were investigated in a systematic way by employing the dyes Acid Orange 7 (AO7) and Methyl Orange (MO) as substrates in terms of their degradation or conversion rates. 4.0% WO(x)/TiO(2) nanocomposite demonstrated the best reactivity under visible light, allowing more efficient usage of solar light. The reduced form of W decreased the band gap and inhibited electron hole recombination efficiently. This composite was characterized by X-ray diffraction spectroscopy (XRD), UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). A series of experiments were conducted to investigate the operational parameters under visible light irradiation such as optimization of nanocomposites wt%, change of pH, reuse of catalyst and initial dye concentration. The kinetics of the dyes degradation was found to follow the Langmuir-Hinshelwood model. Decomposition or mineralization was investigated with the changes of absorption spectra, pH, degradation efficiency and TOC removal in visible irradiation systems. FT-IR spectroscopy of these adsorbed dyes on WO(x)/TiO(2) powder provided an insight to the mode of its adsorption on WO(x)/TiO(2). It was found that the dye adsorbed on WO(x)/TiO(2) underwent a series of oxidation steps which lead to decolorization and formation of a number of intermediates mainly aromatic and aliphatic acids. These intermediates were quantified by GC/GC-MS.

  11. The development and amino acid binding ability of nano-materials based on azo derivatives: theory and experiment.

    PubMed

    Shang, Xuefang; Du, Jinge; Yang, Wancai; Liu, Yun; Fu, Zhiyuan; Wei, Xiaofang; Yan, Ruifang; Yao, Ningcong; Guo, Yaping; Zhang, Jinlian; Xu, Xiufang

    2014-05-01

    Two nano-material-containing azo groups have been designed and developed, and the binding ability of nano-materials with various amino acids has been characterized by UV-vis and fluorescence titrations. Results indicated that two nano-materials showed the strongest binding ability for homocysteine among twenty normal kinds of amino acids (alanine, valine, leucine, isoleucine, methionine, aspartic acid, glutamic acid, arginine, glycine, serine, threonine, asparagine, phenylalanine, histidine, tryptophan, proline, lysine, glutamine, tyrosine and homocysteine). The reason for the high sensitivity for homocysteine was that two nano-materials containing an aldehyde group reacted with SH in homocysteine and afforded very stable thiazolidine derivatives. Theoretical investigation further illustrated the possible binding mode in host-guest interaction and the roles of molecular frontier orbitals in molecular interplay. Thus, the two nano-materials can be used as optical sensors for the detection of homocysteine.

  12. Enhanced photocatalytic activity and stability of alumina supported hematite for azo-dye degradation in aerated aqueous suspension.

    PubMed

    Li, Zhen; Sheng, Jiayi; Wang, Yan; Xu, Yiming

    2013-06-15

    Silica supported hematite (Fe2O3/silica) that is more active but less stable than the supported hematite for organic photodegradation in aqueous solution has been reported. In this work, we report on alumina supported hematite (Fe2O3/alumina) with significantly improved activity and stability. The catalysts were prepared by mixing alumina with a pre-made colloidal iron oxide at various loading (0-100 wt %), followed by sintering at different temperatures (200-900 °C). Solid characterization with X-ray diffraction and N2 adsorption showed that hematite particles were small in size, and large in surface area, as compared with the unsupported hematite prepared in parallel. The catalyst activity was evaluated with anionic Orange II as a model substrate, and the reaction was carried out in aerated aqueous suspension under light irradiation at wavelengths longer than 320 nm. As the Fe2O3 loading on alumina or the catalyst sintering temperature increased, the apparent rate constant of dye degradation increased, and then decreased. The maximum rate of dye degradation was obtained with 25 wt % Fe2O3/alumina, sintered at 400 °C. Moreover, five consecutive experiments for dye photodegradation showed that Fe2O3/alumina was much more stable than Fe2O3/silica, due to alumina that has a positively charged surface and thus facilitates the dissolved iron species back onto iron oxide. The higher activity of Fe2O3/alumina than Fe2O3/silica and bare hematite is ascribed to the combined effect between the reduced particle size of hematite and the enhanced surface adsorption of dye on the catalyst.

  13. Azo dye oxidation with hydrogen peroxide catalysed by manganese 1,4,7-triazacyclononane complexes in aqueous solution.

    PubMed

    Gilbert, Bruce C; Smith, John R Lindsay; Newton, Maurice S; Oakes, John; Pons i Prats, Roger

    2003-05-07

    A kinetic and mechanistic study is reported of the oxidation of a number of azonaphthol dyes with hydrogen peroxide in aqueous solution, catalysed by some mono and dinuclear manganese(IV) complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3TACN). The results of UV-Vis investigations, augmented by EPR and ESI-MS studies, are described for a series of experiments in which concentrations, pH and ionic strength have been varied. The reactions are characterised by an induction period followed by a relatively rapid oxidation. For the dinuclear manganese complex 2, these are consistent with an initial perhydrolysis of the manganese complex involving both the dye anion and HO2-, to give mononuclear manganese species and the operation of a catalytic cycle incorporating MnIIIL(OH)3, O = MnVL(OH)2 and MnIVL(OH)3 (L = Me3TACN) (cf. the reactions of peroxidase enzymes). ESI-MS results provide evidence for the formation and reaction (with the dye) of MnIVL(OH)3. With the mononuclear manganese complex MnIVL(OMe)3, there is a short lag-phase attributed to perhydrolysis by HO2- followed by the same catalytic cycle.

  14. Preparation and characterization of lanthanide-azo-dye coordination polymers and polymer thin films via layer-by-layer depositions.

    PubMed

    Han, Li-Wei; Lü, Jian; Liu, Tian-Fu; Gao, Shui-Ying; Cao, Rong

    2010-12-07

    A series of tartrazine-lanthanide dye compounds has been synthesized and characterized. Structural studies reveal that the light rare-earth elements La, Ce, Pr and Nd form coordination compounds with tartrazine ligands in a 1:1 ratio and result in 1-D 'fish-bone' chain-like structures having uncoordinated organosulfonate groups on each side of the chain. However, reactions of tartrazine and heavy rare-earth elements Ho, Er, Tm and Yb, in the presence of auxiliary 1,10-phenanthroline, give new 1-D coordination polymers in which uncoordinated organosulfonate groups are located on the same side of the chains. The tartrazine ligands display similar but slightly different coordination modes in both types of structures and the 1,10-phenanthroline plays a vital role in the formation of heavy rare-earth dye compounds. Based on the knowledge of their structures, the light rare-earth dye compounds were utilized to assemble with positively-charged PEI into multilayer thin films by means of layer-by-layer depositions. The as-synthesized thin films showed enhanced stability and consistency on solid surfaces.

  15. Surfactant anchoring and aggregate structure at silica nanoparticles: a persuasive facade for the adsorption of azo dye.

    PubMed

    Chaudhary, Savita; Sood, Aastha; Mehta, S K

    2014-09-01

    Nanotechnology's aptitude to silhouette matter at the scale of the nanometer has unlocked the flap to new inventions of applications in material science and nanomedicine. Engineered silica nanoparticles are key actor of this strategy. The amphitheatre of silica nanoparticles is inexplicably bilateral. Silica particles play essential function in everyday commercial purposes for instance energy storage, chemical and biological sensors, food processing and catalysis. One of the most appealing applications to emerge in the recent years is the use of silica particles for cleaning up contaminants in groundwater, soil and sediments. Herein this work, surfactant modified silica nanoparticles with unique surface and pore properties as well as high surface areas have been extensively investigated as an alternative for the dye removal. The physical and chemical characterizations of adsorbent have been studied using FTIR and scanning electron microscopy. The present investigation aims to explore the comparative effect of different surfactants during the formation of the target composite materials. The effects of various parameters like pH, adsorbent doses, dye concentration, addition of salt have also been investigated. These findings indicate that the nano silica particles are effective materials for dye removal and can be used to alleviate environmental problems.

  16. Treatment of a simulated textile wastewater containing the Reactive Orange 16 azo dye by a combination of ozonation and moving-bed biofilm reactor: evaluating the performance, toxicity, and oxidation by-products.

    PubMed

    Castro, Francine D; Bassin, João Paulo; Dezotti, Márcia

    2017-03-01

    In this study, an aqueous solution containing the azo dye Reactive Orange 16 (RO16) was subjected to two sequential treatment processes, namely: ozonation and biological treatment in a moving-bed biofilm reactor (MBBR). The most appropriate ozonation pretreatment conditions for the biological process and the toxicity of the by-products resulting from RO16 ozone oxidation were evaluated. The results showed that more than 97 % of color removal from the dye solutions with RO16 concentrations ranging from 25 to 100 mg/L was observed in 5 min of ozone exposure. However, the maximum total organic carbon removal achieved by ozonation was only 48 %, indicating partial mineralization of the dye. Eleven intermediate organic compounds resulting from ozone treatment of RO16 solution were identified by LC/MS analyses at different contact times. The toxicity of the dye-containing solution decreased after 2 min of ozonation, but increased at longer contact times. The results further demonstrated that the ozonolysis products did not affect the performance of the subsequent MBBR, which achieved an average chemical oxygen demand (COD) and ammonium removal of 93 ± 1 and 97 ± 2 %, respectively. A second MBBR system fed with non-ozonated dye-containing wastewater was run in parallel for comparison purposes. This reactor also showed an appreciable COD (90 ± 1 %) and ammonium removal (97 ± 2 %), but was not effective in removing color, which remained practically invariable over the system. The use of short ozonation times (5 min) and a compact MBBR has shown to be effective for the treatment of the simulated textile wastewater containing the RO16 azo dye.

  17. Accurate mass measurements for the confirmation of Sudan azo-dyes in hot chilli products by capillary liquid chromatography-electrospray tandem quadrupole orthogonal-acceleration time of flight mass spectrometry.

    PubMed

    Calbiani, F; Careri, M; Elviri, L; Mangia, A; Zagnoni, I

    2004-11-26

    The potential of capillary liquid chromatography (microLC)-quadrupole/time-of-flight mass spectrometry (Q-TOF MS) for the confirmation of Sudan I, II, III and IV azo-dyes as contaminants in hot-chilli food products was demonstrated. Using the microLC-electrospray ionization (ESI)-Q-TOF MS technique, accurate mass measurements of Sudan dyes were performed both on standard solutions and on matrices. Precision of exact mass measurements was calculated taking into account the ion statistics according to the number of ion sampled in the measurement. Accurate mass measurements by MS/MS experiments were performed to elucidate azo-dye fragmentation patterns. Selectivity of the microLC-Q-TOF MS method was assessed by evaluating matrix suppression effects by pre-column injection of blank hot chilli tomato sauce matrices. The results were compared with those obtained on a LC-triple quadrupole-MS system. Confirmation of Sudan I present in hot chill tomato sauce samples was obtained by accurate mass measurements. In real samples trueness of exact mass measurements was estimated to be 1.6 and 4.4 ppm when calculated for hot chilli tomato sauce and hot chilli tomato with cheese sauce samples, respectively; precision was calculated around 9.5 ppm.

  18. Uniform TiO2-SiO2 hollow nanospheres: Synthesis, characterization and enhanced adsorption-photodegradation of azo dyes and phenol

    NASA Astrophysics Data System (ADS)

    Guo, Na; Liang, Yimai; Lan, Shi; Liu, Lu; Ji, Guijuan; Gan, Shucai; Zou, Haifeng; Xu, Xuechun

    2014-06-01

    TiO2-SiO2 hollow nanospheres with remarkable enhanced photocatalytic performance have been fabricated by sol-gel method. The hollow sphere possesses both high phototcatalytic activity and adsorption capability. The as-prepared samples were characterized by XRD, SEM, TEM, FTIR, XPS, BJH and TGA/DSC. The experiment results show that, the photocatalyst calcined at 500 °C with Ti/Si ratio of 5:1 (denoted as 5T/S-500) displayed superiorities in both textural and functional properties with the enhanced degradation efficiency on azo dyes (methylene blue, methyl orange) and phenol. The high adsorption capability of organic poisonous contaminants onto 5T/S-500 in aqueous solution demonstrated that the photocatalyst can remove the contaminants from water effectively even without illumination. The TEM and SEM morphologies demonstrated unique hollow and coarse structure of 5T/S-500. Structural analysis showed that Si was doped into the lattice of TiO2 and SiO2 nanoparticles can work as a surface modifier on TiO2. The surface area of 5T/S-500 is 1105 m2/g, 14.5 times as great as that of the pure hollow TiO2 nanosphere, confirms the effect of SiO2 on the improvement of specific surface area. The high photocatalytic activities and high adsorption ability for organic poisonous contaminants demonstrate that the nanocomposite of TiO2-SiO2 is a promising candidate material for future treatment of contaminated water.

  19. Environmental assessment of the degradation potential of mushroom fruit bodies of Pleurotus ostreatus (Jacq.: Fr.) P. Kumm. towards synthetic azo dyes and contaminating effluents collected from textile industries in Karnataka, India.

    PubMed

    Skariyachan, Sinosh; Prasanna, Apoorva; Manjunath, Sirisha P; Karanth, Soujanya S; Nazre, Ambika

    2016-02-01

    Pleurotus ostreatus (Jacq.: Fr.) P. Kumm. is one of the edible mushrooms currently gaining attention as environmental restorer. The present study explores the potential of P. ostreatus (Jacq.: Fr.) P. Kumm. in degradation of textile dyes and effluents. The mushroom cultivation was carried out using paddy bed as substrate. The fully grown mushroom fruit bodies were used as a bioremediation agent against two industrially important azo dyes such as nylon blue and cotton yellow and few effluents collected from various textile industries in Karnataka, India. The ideal growth parameters such as temperature, pH, and dye concentrations for effective degradation were carried out. One of the main enzymes, laccase, responsible for biodegradation, was partially characterized. The degradation was found to be ideal at pH 3.0 and temperature at 26-28 °C. This study demonstrated a percentage degradation of 78.10, 90.81, 82.5, and 64.88 for dye samples such as nylon blue (50 ppm), cotton yellow (350 ppm), KSIC effluents, and Ramanagar effluents at 28 °C within 15th days respectively in comparison with other temperature conditions. Similarly, a percentage degradation of 35.99, 33.33, 76.13 and 25.8 for nylon blue (50 ppm), cotton yellow (350 ppm), Karnataka Silk Industries Corporation (KSIC) effluents and Ramnagar effluents were observed at pH 3.0 within 15 days, respectively (p < 0.05). Thus, the current study concluded that the utilization of P. ostreatus (Jacq.: Fr.) P. Kumm. at ideal environmental conditions is a cost-effective and eco-friendly approach for the degradation of various azo dyes and textile effluents which are harmful to the ecosystem.

  20. Determination of banned 10 azo-dyes in hot chili products by gel permeation chromatography-liquid chromatography-electrospray ionization-tandem mass spectrometry.

    PubMed

    Sun, Han-Wen; Wang, Feng-Chi; Ai, Lian-Feng

    2007-09-14

    An accurate method based on the use of gel permeation chromatography (GPC)-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (GPC-LC-ESI-MS/MS) was devised for the simultaneous determination of Sudan (I-IV), Sudan Orange G, Sudan Red B, Sudan Red G, Sudan Red 7B, Butter Yellow and Para Red in hot chili products. A GPC clean-up procedure was developed for simultaneous quantification of 10 dyes in hot chili and hot chili products avoiding some interference and permitting multiple injections without damaging the column. A HPLC was performed on an Inertsil C18 column using a multistep gradient elution with 0.1% formic acid and methanol as the mobile phase. Mass spectral acquisition was done in positive ion mode. Linearity of around three orders in the magnitude of concentration was generally obtained with the correlation coefficients (r2) of 0.9984-0.9997. Limit of detection (LOD) and limit of quantification (LOQ) for the investigated dyes were in the ranges of 0.1-1.8 and 0.4-5.0 microg/kg depending on matrices, respectively. The recoveries of the 10 synthetic dyes in five matrices ranged from 81.7 to 92.9%. The intra- and inter-day precision (RSDs) was between 2.9-7.8 and 3.9-8.1%, respectively. This method has been applied successfully for the determination of the studied 10 banned dyes in hot chili products.

  1. Immobilization of TiO2 nanopowder on glass beads for the photocatalytic decolorization of an azo dye C.I. Direct Red 23.

    PubMed

    Daneshvar, N; Salari, D; Niaei, A; Rasoulifard, M H; Khataee, A R

    2005-01-01

    TiO2 supported on glass beads was prepared and its photocatalytic activity was determined by photooxidation of the commercial textile dye, C.I. Direct Red 23, in aqueous solution illuminated by a UV-C lamp (30 W). The progress of photocatalytic decolorization of the C.I. Direct Red 23 was studied by measuring the absorbance at lambda(max) = 507 nm by UV Vis spectrophotometer. The experiments indicated that both UV light and TiO2 were needed for the effective destruction of the dye. The effect of pH on the rate of decolorization efficiency was followed in the pH range 2-12. Acidic pH range was found to favor the decolorization rate. The addition of a proper amount of hydrogen peroxide improved the decolorization, whereas the excess hydrogen peroxide quenched the formation of hydroxyl radicals (*OH). The electrical energy consumption per order of magnitude for photocatalytic decolorization of the dye was lower in the UV/TiO2/H2O2 process than that in the UV/TiO2 process. In the real wastewater sample the efficiency of the method was determined by measuring the changes in the absorption spectra of the dye solution during photodegradation. Our results indicated that during the photooxidation process, the decolorization efficiency was more than 80% at irradiation time of 3 h.

  2. Application of the mixture design to optimise the formulation of active consortia to decolorize azo-dye methyl red.

    PubMed

    Ayed, Lamia; Harbi, Besma; Cheref, Abdelkrim; Bakhrouf, Amina; Achour, Sami

    2010-01-01

    With the aid of analysis software (Minitab 14.0), the formulation of pure culture in Mineral Salts Medium (MSM) can be optimized for several responses and the best formulation can be obtained. The influence of the different mixtures of three strains in the pure culture in MSM on the flavor components in decolorization of Methyl Red (with initial total cell density fixed at OD600 = 1 and in addition of 750 ppm of dye) was studied using equilateral triangle diagram and mixture experimental design to assess color and COD removal during species evolution. The regression model on microorganism composition and main metabolites was established. The results suggested that the highest predictable specific decolorization rate and Chemical Oxygen Demand (COD) were 77.97 and 93.77%. Based on these, the response values that satisfied all expectations were optimized, and the optimal composition of the mixed consortium for the dedolorization and COD removal were (Sphingomonas paucimobilis 45.20%, Bacillus sp 61.94% and Staphylococcus epidermidis 80.00%) and (Sphingomonas paucimobilis 77.03%, Bacillus sp 86.42% and Staphylococcus epidermidis 71.74%) respectively. Very high regression coefficient between the variables and the responses: decolorization and COD removal were respectively R(2)=0.96 and 0.81 indicated excellent evaluation of experimental data by polynomial regression model.

  3. Polyacrylamide-based semi-interpenetrating networks for entrapment of laccase and their use in azo dye decolorization.

    PubMed

    Koklukaya, Selva Zeynep; Sezer, Serdar; Aksoy, Serpil; Hasirci, Nesrin

    2016-09-01

    In this study, laccase from Trametes versicolor was immobilized in poly(acrylamide-crotonic acid)/sodium alginate [P(AAm-CrA)/alginate], poly(acrylamide-crotonic acid)/K-carrageenan [(P(AAm-CrA)/K-car)], poly(acrylamide-citraconic acid)/sodium alginate (P(AAm-CA)/alginate), and poly(acrylamide-citraconic acid)/K-carrageenan (P(AAm-CA)/K-car) semi-interpenetrating network by entrapment method. Optimum pH and temperatures values were determined between 5.0-6.0 and 40-50 °C for free laccase (FL) and immobilized laccases, respectively. After 42 days of storage at 4 °C, FL and immobilized laccases retained their original activities in the range of 55%-73%. Percent decolorization of Acid Orange 52 by free enyzme and enyzmes immobilized in hydrogels was found between 63% and 39%. Percent decolorization of Acid Orange 52 in the presence of mediator by free enyzme was found 73% and enyzmes immobilized in hydrogels were found as 73%.

  4. Process development for the batch and bulk removal and recovery of a hazardous, water-soluble azo dye (Metanil Yellow) by adsorption over waste materials (Bottom Ash and De-Oiled Soya).

    PubMed

    Mittal, Alok; Gupta, V K; Malviya, Arti; Mittal, Jyoti

    2008-03-01

    Bottom Ash and De-Oiled Soya have been used as adsorbents for the removal of a hazardous azo dye-Metanil Yellow from its aqueous solutions. Adsorption of Metanil Yellow on these adsorbents has been studied as function of time, temperature, concentration and pH. Batch adsorption studies, kinetic studies and column operations enabled extraction of lethal dye from wastewaters. Adsorption equilibrium data confirms both Langmuir and Freundlich isotherm models and monolayer coverage of dye over adsorbents. Kinetic data have been employed to calculate specific rate constants, indicating thereby involvement of first order kinetics in the on-going adsorption and activation energy was determined as 0.813 and 1.060 kJ mol(-1) for Bottom Ash and De-Oiled Soya, respectively. For both adsorbents, the adsorption process has been found governing by film diffusion, over the entire concentration range. Column operations have also been performed for the bulk removal of the dye and also to examine the practical utilization of fixed bed adsorption technique in elimination of dangerous effluent. Saturation factors for Bottom Ash and De-Oiled Soya columns have been calculated as 99.15 and 99.38%, respectively. Attempts have also been made to regenerate the dye from the exhausted columns using aqueous sodium hydroxide as eluent.

  5. Studies on monolayers. Part 1. Surface tension and absorption spectroscopic measurements of monolayers of surface-active azo and stilbene dyes

    SciTech Connect

    Heesemann, J.

    1980-03-26

    In order to develop new molecules as function components of monolayer assemblies, a series of 9 surface-active azo and stilbene compounds are synthesized. Their monolayer properties at the air-water interface are studied by surface pressure-surface area measurements and spectroscopic techniques. The results show that small changes in the molecular structure of the surfactants (such as, length of the fatty acid chain and type of the chromphore) have an immense influence on the monolayer properties. For monolayers of compounds I and III-VIII, van der Walls-like isotherms are obtained, which show a liquid expanded state, a phase transition region, and a condensed state. From monolayer absorbance spectra it is found that in the liquid expanded state at 100 to 110 sq angstroms/molecule the chromphores lie flatly on the water surface, forming monomers. The phase transition region of the isotherms can be assigned to a change of orientation of the chromophore axis (horizontal to vertical) and an aggregation process of the chromophores (monomers to H aggregates). 20 references.

  6. Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

    2016-10-01

    Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells.

  7. Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis

    PubMed Central

    Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

    2016-01-01

    Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells. PMID:27767196

  8. Toxicity removal assessments related to degradation pathways of azo dyes: Toward an optimization of Electro-Fenton treatment.

    PubMed

    Le, Thi Xuan Huong; Nguyen, Thi Van; Yacouba, Zoulkifli Amadou; Zoungrana, Laetitia; Avril, Florent; Petit, Eddy; Mendret, Julie; Bonniol, Valerie; Bechelany, Mikhael; Lacour, Stella; Lesage, Geoffroy; Cretin, Marc

    2016-10-01

    The degradation pathway of Acid Orange 7 (AO7) by Electro-Fenton process using carbon felt cathode was investigated via HPLC-UV and LC-MS, IC, TOC analysis and bioassays (Vibrio Fischeri 81.9% Microtox(®) screening tests). The TOC removal of AO7 reached 96.2% after 8 h treatment with the optimal applied current density at -8.3 mA cm(-2) and 0.2 mM catalyst concentration. The toxicity of treated solution increased rapidly to its highest value at the early stage of electrolysis (several minutes), corresponding to the formation of intermediate poisonous aromatic compounds such as 1,2-naphthaquinone (NAPQ) and 1,4-benzoquinone (BZQ). Then, the subsequent formation of aliphatic short-chain carboxylic acids like acetic acid, formic acid, before the complete mineralization, leaded to a non-toxic solution after 270 min for 500 mL of AO7 (1 mM). Moreover, a quantitative analysis of inorganic ions (i.e. ammonium, nitrate, sulfate) produced during the course of degradation could help to verify molar balance with regard to original nitrogen and sulfur elements. To conclude, a clear degradation pathway of AO7 was proposed, and could further be applied to other persistent pharmaceuticals in aquatic environment.

  9. Studies on monolayers. Part 2. Design monolayer assemblies of mixed films of surface-active azo dyes

    SciTech Connect

    Heesemann, J.

    1980-03-26

    This work is concerned with designed self-organization of surfactants to highly organized monomolecular layers, which may be used for molecular engineering. The monolayer properties of 2-component and 3-component films are studied at the air-water and air-glass interface. The 2-component films consist of the chromophoric diglyceride and the chromophoric triglyceride (one fatty acid residue was substituted by n-(4'nitro-1'-phenylazo-P-phe methylaminopropionic acid). The Pi-Alpha curves of the mixed films showed marked deviations from the addivity rule. For the mole fraction 0.35 of the diglyceride component the surface pressure-area isotherm shows the characteristics of an eutectic film. The results of absorbance spectra and surface pressure-area isotherms suggest that the close-packed monolayer of the eutectic mixture consist of molecules in the stretched conformation with the chromophores in a card-pack-like arrangement (H aggregates). The 3-component films consists of stearic acid, stearylamine, and 12-(4'nitro-4- dimethylaminoazobenzene-3'-car acid. Neutral 3-component films are deposited onto glass slides and absorbance spectra are measured with polarized light.

  10. The Electropolymerization and Characterizations of Acid Red Dye Doped Polyaniline

    NASA Astrophysics Data System (ADS)

    Li, Xin; Liang, Fei-Yue; Liao, Jia-Xing; Wang, Rui; Zheng, Yi-Ping; Xian, Ze-Yu

    2016-05-01

    The electrochromic properties of an electrochemical polymerized composite consisted of polyaniline doped with acid red dye (PANI-ARD) are reported. The structures of PANIARD were characterized via cycle voltammograms, spectroelectrochemistry and colorimetric analysis. Film of the PANI-ARD composites of different concentrations appears violet, aubergine in the neutral state and darkblue in the oxidized state, which are different from the pure PANI of yellow (-0.8V) and blue (1.0V). The oxidation and reduction response speed of PANI-ARD was a bit lower than those obtained in pure PANI. It is shown that acid dye doping is an effective method to broaden the color change range of the electrochromicmateials.

  11. Central composite design optimization of pilot plant fluidized-bed heterogeneous Fenton process for degradation of an azo dye.

    PubMed

    Aghdasinia, Hassan; Bagheri, Rasoul; Vahid, Behrouz; Khataee, Alireza

    2016-11-01

    Optimization of Acid Yellow 36 (AY36) degradation by heterogeneous Fenton process in a recirculated fluidized-bed reactor was studied using central composite design (CCD). Natural pyrite was applied as the catalyst characterized by X-ray diffraction and scanning electron microscopy. The CCD model was developed for the estimation of degradation efficiency as a function of independent operational parameters including hydrogen peroxide concentration (0.5-2.5 mmol/L), initial AY36 concentration (5-25 mg/L), pH (3-9) and catalyst dosage (0.4-1.2 mg/L). The obtained data from the model are in good agreement with the experimental data (R(2 )= 0.964). Moreover, this model is applicable not only to determine the optimized experimental conditions for maximum AY36 degradation, but also to find individual and interactive effects of the mentioned parameters. Finally, gas chromatography-mass spectroscopy (GC-MS) was utilized for the identification of some degradation intermediates and a plausible degradation pathway was proposed.

  12. Activated carbon adsorptive removal of azo dye and peroxydisulfate regeneration: from a batch study to continuous column operation.

    PubMed

    Li, Jing; Du, Yue; Deng, Bin; Zhu, Kangmeng; Zhang, Hui

    2016-12-17

    The performance of activated carbon (AC) for the adsorption of Acid Orange 7 (AO7) was investigated in both batch and column studies. The optimal conditions for adsorption process in batch study were found to be a stirring speed of 500 rpm, AC dosage of 5 g/L, and initial AO7 concentration of 100 mg/L. The spent AC was then treated with peroxydisulfate (PDS), and the regenerated AC was used again to adsorb AO7. Both pseudo-first-order and pseudo-second-order rate models for adsorption kinetics were investigated, and the results showed that the latter model was more appropriate. The effects of regeneration time, PDS concentration, and stirring speed on AO7-spent AC regeneration were investigated in batch studies, and the optimal conditions were time 2 h, stirring speed 700 rpm, and PDS concentration 10 g/L. Under the same adsorption conditions, 89% AO7 could be decolorized by adsorption using regenerated AC. In the column studies, the effect of flow rate was investigated and the adsorption capacity was nearly the same when the flow rate rose from 7.9 to 11.4 mL/min, but it decreased significantly when the flow rate was increased to 15.2 mL/min. The performance of regenerated AC in the column was also investigated, and a slight increase in the adsorption capacity was observed in the second adsorption cycle. However, the adsorption capacity decreased to some extent in the third cycle due to the consumption of C-OH group on the AC surface during PDS regeneration.

  13. Adsorption Capability of Cationic Dyes (Methylene Blue and Crystal Violet) onto Poly-γ-glutamic Acid.

    PubMed

    Ogata, Fumihiko; Nagai, Noriaki; Kawasaki, Naohito

    2017-01-01

    In this study, the adsorption capability of cationic dyes, which were methylene blue and crystal violet, by poly-γ-glutamic acid (PGA) in a single or binary solution system was investigated. The effect of the molecular weight of PGA, initial dye concentration, solution pH, and temperature on the adsorption of dyes was evaluated. The adsorption mechanism of dyes onto PGA was the interaction between -COOH group on the PGA surface and the polarity groups of dyes. These results indicated that PGA is useful for removal of dyes and cationic organic compounds from a single or binary solution system.

  14. Understanding the degradation of Congo red and bacterial diversity in an air-cathode microbial fuel cell being evaluated for simultaneous azo dye removal from wastewater and bioelectricity generation.

    PubMed

    Sun, Jian; Li, Youming; Hu, Yongyou; Hou, Bin; Zhang, Yaping; Li, Sizhe

    2013-04-01

    We investigated the mechanism of Congo red degradation and bacterial diversity in a single-chambered microbial fuel cell (MFC) incorporating a microfiltration membrane and air-cathode. The MFC was operated continuously for more than 4 months using a mixture of Congo red and glucose as fuel. We demonstrated that the Congo red azo bonds were reduced at the anode to form aromatic amines. This is consistent with the known mechanism of anaerobic biodegradation of azo dyes. The MFC developed a less dense biofilm at the anode in the presence of Congo red compared to its absence indicating that Congo red degradation negatively affected biofilm formation. Denaturing gradient gel electrophoresis and direct 16S ribosomal DNA gene nucleotide sequencing revealed that the microbial communities differed depending on whether Congo red was present in the MFC. Geobacter-like species known to generate electricity were detected in the presence or absence of Congo red. In contrast, Azospirillum, Methylobacterium, Rhodobacter, Desulfovibrio, Trichococcus, and Bacteroides species were only detected in its presence. These species were most likely responsible for degrading Congo red.

  15. Salicylic Acid-Based Organic Dyes Acting as the Photosensitizer for Solar Cells.

    PubMed

    Hong, Sungjun; Park, Jae-Hyeong; Han, Ah-Reum; Ko, Kwan-Woo; Eom, Jin Hee; Namgoong, Sung Keon; Lo, Alvie S V; Gordon, Keith C; Yoon, Sungho; Han, Chi-Hwan

    2016-05-01

    A D-π-A metal-free organic dye, featuring salicylic acid as a novel acceptor/anchoring unit, has been designed, synthesized and applied to dye-sensitized solar cell. The detailed photophysical, electrochemical, photovoltaic and sensitizing properties of the organic dye were investigated, in addition to the computational studies of the dye and dye-(TiO2)6 system. A solar cell device using this new organic dye as a sensitizer produced a solar to electric power conversion efficiency (PCE) of 3.49% (J(sc) = 6.69 mAcm-2, V(oc) = 0.74 V and ff = 0.70) under 100 mWcm(-2) simulated AM 1.5 G solar irradiation, demonstrating that the salicylic acid-based organic dye is a suitable alternative to currently used organometallic dyes.

  16. A novel ammonia-assisted method for the direct synthesis of Mn3O4 nanoparticles at room temperature and their catalytic activity during the rapid degradation of azo dyes

    NASA Astrophysics Data System (ADS)

    Mansournia, Mohammadreza; Azizi, Fatemeh; Rakhshan, Narges

    2015-05-01

    In this study, we prepared trimanganese tetroxide nanoparticles from MnCl2 solution in an ammonia atmosphere using a new surfactant-free method at room temperature. We analyzed and characterized the effects of different processing conditions, such as the concentrations of manganese and the ammonia source, as well as the reaction time, on the structure, purity, and morphology of the products using powder X-ray diffraction (XRD), scanning electron microscopy, and Fourier transformation infrared spectroscopy (FTIR) techniques. The XRD and FTIR analyses confirmed that the prepared products comprised single phase Mn3O4. At room temperature, the paramagnetic characteristics were also verified by vibrating sample magnetometry. Furthermore, we tested the catalytic activity of the nanoparticles during the degradation of methyl orange and Congo red, which are organic pollutants. Our experiments demonstrated the rapid color removal and reduction in the chemical oxygen demand (>70% and >50% within 10 min, respectively) using aqueous solutions of azo dyes.

  17. Nanostructured semiconductor films for photocatalysis. Photoelectrochemical behavior of SnO{sub 2}/TiO{sub 2} composite systems and its role in photocatalytic degradation of a textile azo dye

    SciTech Connect

    Vinodgopal, K.; Bedja, I.; Kamat, P.V.

    1996-08-01

    Nanostructured semiconductor films of SnO{sub 2}, TiO{sub 2}, and SnO{sub 2}/TiO{sub 2} have been employed for electrochemically assisted photocatalytic degradation of a textile azo dye naphthol blue black (NBB). The degradation rate is significantly higher for SnO{sub 2}/TiO{sub 2} composite films than SnO{sub 2} and TiO{sub 2} films alone. An effort has been made to correlate the photoelectrochemical behavior of these films to the rate of photocatalytic degradation of NBB. The enhanced degradation rate of NBB using composite semiconductor films is attributed to increased charge separation in these systems. Photoelectrochemical and photocatalytic degradation experiments carried out in both nitrogen- and oxygen-saturated solutions with an externally applied electrochemical bias provide useful information in optimizing semiconductor concentrations in a composite film. 83 refs., 9 figs., 1 tab.

  18. Decolourisation Capabilities of Ligninolytic Enzymes Produced by Marasmius cladophyllus UMAS MS8 on Remazol Brilliant Blue R and Other Azo Dyes

    PubMed Central

    Roslan, Hairul Azman

    2017-01-01

    Marasmius cladophyllus was examined for its ability to degradatively decolourise the recalcitrant dye Remazol Brilliant Blue R (RBBR) and screened for the production of ligninolytic enzymes using specific substrates. Monitoring dye decolourisation by the decrease in absorbance ratio of A592/A500 shows that the decolourisation of RBBR dye was associated with the dye degradation. Marasmius cladophyllus produces laccase and lignin peroxidase in glucose minimal liquid medium containing RBBR. Both enzyme activities were increased, with laccase activity recorded 70 times higher reaching up to 390 U L−1 on day 12. Further in vitro RBBR dye decolourisation using the culture medium shows that laccase activity was correlated with the dye decolourisation. Fresh RBBR dye continuously supplemented into the decolourised culture medium was further decolourised much faster in the subsequent round of the RBBR dye decolourisation. In vitro dye decolourisation using the crude laccase not only decolourised 76% of RBBR dye in just 19 hours but also decolourised 54% of Orange G and 33% of Congo red at the same period of time without the use of any exogenous mediator. This rapid dye decolourisation ability of the enzymes produced by M. cladophyllus thus suggested its possible application in the bioremediation of dye containing wastewater. PMID:28168194

  19. Effect of CeO2 doping on catalytic activity of Fe2O3/gamma-Al2O(3) catalyst for catalytic wet peroxide oxidation of azo dyes.

    PubMed

    Liu, Yan; Sun, Dezhi

    2007-05-08

    In order to find a catalyst with high activity and stability for catalytic wet peroxide oxidation (CWPO) process under normal condition, with Fe(2)O(3)/gamma-Al(2)O(3) and Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) catalysts prepared by impregnation method, the effect of CeO(2) doping on the structure and catalytic activity of Fe(2)O(3)/gamma-Al(2)O(3) for catalytic wet peroxide oxidation of azo dyes at 25 degrees C and atmospheric pressure is evaluated using BET, SEM, XRF, XRD, XPS and chemical analysis techniques, and test results show that, better dispersion and smaller size of Fe(2)O(3) crystal can be achieved by adding CeO(2), and the content of chemisorbed oxygen can also be increased on the surface of catalyst. CWPO experimental results indicate that azo dyes in simulated wastewater can be efficiently mineralized and the catalytic activity of Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) can be increased by about 10% compared with that of Fe(2)O(3)/gamma-Al(2)O(3) because of the promotion of the structural and redox properties of the ferric oxide by ceria doped. Leaching tests indicate that Fe(2)O(3)/gamma-Al(2)O(3) and Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) are stable with a negligible amount of irons found in the aqueous solution after reaction for 2h. It can therefore be concluded from results and discussion that in comparison with Fe(2)O(3)/gamma-Al(2)O(3), Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) is a suitable catalyst, which can effectively degrade contaminants at normal temperature and atmospheric pressure.

  20. Study on the removal of acid dyes using chitosan as a natural coagulant/coagulant aid.

    PubMed

    Zonoozi, M H; Alavi Moghaddam, M R; Arami, M

    2011-01-01

    Chitosan was selected as a natural coagulating agent for the removal of acid dyes (Acid Blue 292; AB292, and Acid Red 398; AR398) from dye-containing solutions. The study was organised in two phases. In phase 1, chitosan was used alone as a natural coagulant for the removal of the dyes. For this purpose, the effect of different parameters including pH, chitosan dosage and initial dye concentration on the dye removal efficiency was examined. In phase 2 of the study, the application of chitosan as a natural coagulant aid in conjunction with polyaluminium chloride (PAC) was assessed. According to the results of phase 1, the best removal efficiencies occurred in an acidic pH range (less than 6) for both of the dyes. Also, excellent dye removal results (about 90%) were achieved with relatively low dosages of chitosan (30-35 mg L(-1) for AB292 and 50-60 mg L(-1) for AR398). However, the initial concentration of the dyes severely influenced the coagulation performance of chitosan, which can constrain the performance of chitosan as a natural coagulant. On the basis of the results of phase 2, chitosan, as a natural coagulant aid, noticeably enhanced the dye removal efficiency of PAC, especially in the case of AB292. Small amounts of chitosan (3 or 5 mg L(-1)) enhanced the dye removal efficiency of PAC up to 2.5 times for AB292.

  1. Delaminated montmorillonite with iron(III)-TiO₂ species as a photocatalyst for removal of a textile azo-dye from aqueous solution.

    PubMed

    Torres-Luna, Juan A; Carriazo, José G; Sanabria, Nancy R

    2016-01-01

    A set of mesoporous delaminated montmorillonites containing iron(III)-titanium oxide species was synthesized using two minerals: a bentonite as support and an ilmenite as source of Fe-TiO2 species. Several values of both sulphuric acid concentration and temperature were employed to extract Fe-TiO2 species from an ilmenite. Analyses by X-ray fluorescence, X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption confirmed the successful formation of delaminated (or exfoliated) mesoporous structures. Optical properties of solids were determined by UV-Vis diffuse reflectance spectroscopy, and their band gap energy values were also calculated. A small UV-shift of band gap values regarding that of commercial photo-active TiO2 was detected as consequence of the quantum size effect, suggesting that photocatalytic experiments should be performed under UV-radiation assistance. The synthesized solids showed good activity in the photocatalytic oxidation of a textile dye (reactive yellow 145: RY 145), achieving conversions higher than 70% and chemical oxygen demand removal between 60% and 80%.

  2. Permanent hair dye-incorporated hyaluronic acid nanoparticles.

    PubMed

    Lee, Hye-Young; Jeong, Young-Il; Kim, Da-Hye; Choi, Ki-Choon

    2013-01-01

    We prepared p-phenylenediamine (PDA)-incorporated nanoparticles using hyaluronic acid (HA). PDA-incorporated HA nanoparticles have spherical shapes and sizes were less than 300 nm. The results of FT-IR spectra indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation between amine group of PDA and carboxyl group of HA. Furthermore, powder-X-ray diffractogram (XRD) measurement showed that intrinsic crystalline peak of PDA disappeared by formation of nanoparticle with HA at XRD measurement. These results indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation. At drug release study, the higher PDA contents induced faster release rate from nanoparticles. PDA-incorporated nanoparticles showed reduced intrinsic toxicity against HaCaT human keratinocyte cells at MTT assay and apoptosis assay. We suggest that PDA-incorporated HA nanoparticles are promising candidates for novel permanent hair dye.

  3. Optical and thermal properties of azo derivatives of salicylic acid thin films

    NASA Astrophysics Data System (ADS)

    Ghoneim, M. M.; El-Ghamaz, N. A.; El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Serag, L. S.

    2015-02-01

    N-acryloyl-4-aminosalicylic acid (4-AMSA), monomer (HL) and 5-(4‧-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are synthesized and characterized with various physico-chemical techniques. Thin films of 5-(4‧-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are prepared by spin coating technique. The X-ray diffraction (XRD) patterns of 4-aminosalicylic acid (4-ASA) and its derivatives are investigated in powder and thin film forms. Thermal properties of the compounds are investigated by thermogravemetric analysis (TGA). The optical energy gap and the type of optical transition are investigated in the wavelength range (200-2500 nm) for 4-ASA, HL and HLn. The values of fundamental energy gap (Eg) are in the range 3.60-3.69 eV for all compounds and the type of optical transition is found to be indirect allowed. The onset energy gap Eg∗ appeared only for azodye compounds is found to be in the range 0.95-1.55 eV depending on the substituent function groups. The refractive index, n, shows a normal dispersion in the wavelength range 650-2500 nm, while shows anomalous dispersion in the wavelength rang 200-650 nm. The dispersion parameters ε∞, εL, Ed, Eo and N /m∗ are calculated. The photoluminescence phenomena (PL) appear for thin films of 4-ASA and its derivatives show three main emission transitions.

  4. Optical and thermal properties of azo derivatives of salicylic acid thin films.

    PubMed

    Ghoneim, M M; El-Ghamaz, N A; El-Sonbati, A Z; Diab, M A; El-Bindary, A A; Serag, L S

    2015-02-25

    N-acryloyl-4-aminosalicylic acid (4-AMSA), monomer (HL) and 5-(4'-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are synthesized and characterized with various physico-chemical techniques. Thin films of 5-(4'-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are prepared by spin coating technique. The X-ray diffraction (XRD) patterns of 4-aminosalicylic acid (4-ASA) and its derivatives are investigated in powder and thin film forms. Thermal properties of the compounds are investigated by thermogravemetric analysis (TGA). The optical energy gap and the type of optical transition are investigated in the wavelength range (200-2500 nm) for 4-ASA, HL and HLn. The values of fundamental energy gap (Eg) are in the range 3.60-3.69 eV for all compounds and the type of optical transition is found to be indirect allowed. The onset energy gap Eg(∗) appeared only for azodye compounds is found to be in the range 0.95-1.55 eV depending on the substituent function groups. The refractive index, n, shows a normal dispersion in the wavelength range 650-2500 nm, while shows anomalous dispersion in the wavelength rang 200-650 nm. The dispersion parameters ε∞, εL, Ed, Eo and N/m(∗) are calculated. The photoluminescence phenomena (PL) appear for thin films of 4-ASA and its derivatives show three main emission transitions.

  5. Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L.

    NASA Astrophysics Data System (ADS)

    Agustia, Yuda Virgantara; Suyitno, Arifin, Zainal; Sutanto, Bayu

    2016-03-01

    The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, EHOMO and ELUMO was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where Ered = -0.37V, ELUMO = -4.28 eV, Eox = 1.15V, EHOMO = -5.83 eV, and Eband gap = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

  6. Removal of an anionic dye (Acid Blue 92) by coagulation-flocculation using chitosan.

    PubMed

    Szyguła, Agata; Guibal, Eric; Ariño Palacín, María; Ruiz, Montserrat; Sastre, Ana Maria

    2009-07-01

    Chitosan (a biopolymer) is an aminopolysaccharide that can be used for the treatment of colored solutions by coagulation-flocculation (as an alternative to more conventional processes such as sorption). Acid Blue 92 (a sulfonic dye) was selected as a model dye for verifying chitosan's ability to treat textile wastewater. A preliminary experiment demonstrated that chitosan was more efficient at color removal in tap water than in demineralized water, and that a substantially lower concentration of chitosan could be used with tap water. Dye removal reached up to 99% under optimum concentration; i.e., in terms of the acidic solutions and the stoichiometric ratio between the amine groups of the biopolymer and the sulfonic groups in the dye. The flocs were recovered and the dye was efficiently removed using alkaline solutions (0.001-1 M NaOH solutions) and the biopolymer, re-dissolved in acetic acid solution, was reused in a further treatment cycle.

  7. Analysis of the generating action of the acid from PAG using acid sensitive dyes

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Atsushi; Matsumoto, Yoko; Konishi, Hiroko; Moriyasu, Kengo; Morimoto, Yukihiro

    2011-04-01

    The use of acid sensitive dyes to determine the quantity of acid generated from PAG and in the analysis of acid-generating reaction is currently being studied. The method would allow an easy understanding of the PAG acid-generating reaction simply by adding an acid sensitive dye to the resist. In the conventional method, a resist containing a chromogenic substance is applied to a quartz substrate, which is then exposed. Following the exposure, the absorbance of chromogenic component near 530 nm is measured and evaluated with a spectroscope. The rate constant for acid generation (Dill's C parameter) during the exposure is determined based on the relationship between transmittance at 530 nm and the exposure dose. However, the chromogenic substance used in this method degrades over time (fading reaction) after the exposure, resulting in variations in transmittance measurements due to the effects of time between the completion of the exposure and the measurement of transmittance. We devised a prototype instrument capable of in situ measurements of absorbance at 530 nm while irradiating a 193-nm light beam. Using this instrument, we obtained rate constants for acid generation (Dill's C parameter) and examined the differing results obtained with ArF resist polymers of differing PAG concentrations and structures as well as dependence on the quantity of the chromogenic substance.

  8. D-π-A dye system containing cyano-benzoic acid as anchoring group for dye-sensitized solar cells.

    PubMed

    Katono, Masataka; Bessho, Takeru; Meng, Sheng; Humphry-Baker, Robin; Rothenberger, Guido; Zakeeruddin, Shaik M; Kaxiras, Efthimios; Grätzel, Michael

    2011-12-06

    A D-π-A dye (KM-1) incorporating cyano-benzoic acid as a new acceptor/anchoring group has been synthesized for dye-sensitized solar cells (DSCs) with a high molar extinction coefficient of 66,700 M(-1) cm(-1) at 437 nm. Theoretical calculations show that the hydrogen bond between -CN and surface hydroxyl leads to the most stable configuration on the surface of TiO(2). In addition, the adsorption of the dye on TiO(2) follows a Brunauer-Emmett-Teller (BET) isotherm. Multilayer adsorption of KM-1 on TiO(2) seems to take place particularly at higher dye concentrations. DSC device using KM-1 reached a maximum incident photon-to-current conversion efficiency (IPCE) of 84%, with a solar to electric power conversion efficiency (PCE) of 3.3% at AM1.5 G illumination (100 mW cm(-2)). This new type of anchoring group paves a way to design new dyes that combine good visible light harvesting with strong binding to the metal oxide surface.

  9. Homogenous and heterogenous advanced oxidation of two commercial reactive dyes.

    PubMed

    Balcioglu, I A; Arslan, I; Sacan, M T

    2001-07-01

    Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

  10. A Three-Component Assembly Promoted by Boronic Acids Delivers a Modular Fluorophore Platform (BASHY Dyes).

    PubMed

    Santos, Fábio M F; Rosa, João N; Candeias, Nuno R; Carvalho, Cátia Parente; Matos, Ana I; Ventura, Ana E; Florindo, Helena F; Silva, Liana C; Pischel, Uwe; Gois, Pedro M P

    2016-01-26

    The modular assembly of boronic acids with Schiff-base ligands enabled the construction of innovative fluorescent dyes [boronic acid salicylidenehydrazone (BASHY)] with suitable structural and photophysical properties for live cell bioimaging applications. This reaction enabled the straightforward synthesis (yields up to 99%) of structurally diverse and photostable dyes that exhibit a polarity-sensitive green-to-yellow emission with high quantum yields of up to 0.6 in nonpolar environments. These dyes displayed a high brightness (up to 54,000 M(-1) cm(-1)). The promising structural and fluorescence properties of BASHY dyes fostered the preparation of non-cytotoxic, stable, and highly fluorescent poly(lactide-co-glycolide) nanoparticles that were effectively internalized by dendritic cells. The dyes were also shown to selectively stain lipid droplets in HeLa cells, without inducing any appreciable cytotoxicity or competing plasma membrane labeling; this confirmed their potential as fluorescent stains.

  11. Novel amphiphilic polymeric ionic liquid-solid phase micro-extraction membrane for the preconcentration of aniline as degradation product of azo dye Orange G under sonication by liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Mei-Qiang; Wei, Xiao-Qing; Du, Chun-Hui; Ma, Xu-Ming; Jin, Mi-Cong

    2014-07-04

    A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76μgμg(-1) for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0μgL(-1) with a correlation coefficient value of 0.9998. The limit of quantification was 0.5μgL(-1). The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution.

  12. Cobalt ferrite nano-composite coated on glass by Doctor Blade method for photo-catalytic degradation of an azo textile dye Reactive Red 4: XRD, FESEM and DRS investigations.

    PubMed

    Habibi, Mohammad Hossein; Parhizkar, Janan

    2015-11-05

    Cobalt ferrite nano-composite was prepared by hydrothermal route using cobalt nitrate, iron nitrate and ethylene glycol as chelating agent. The nano-composite was coated on glass by Doctor Blade method and annealed at 300 °C. The structural, optical, and photocatalytic properties have been studied by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible spectroscopy (UV-Vis DRS). Powder XRD analysis confirmed formation of CoFe2O4 spinel phase. The estimated particle size from FESEM data was 50 nm. The calculated energy band gaps, obtained by Tauc relation from UV-Vis absorption spectra was 1.3 eV. Photocatalytic degradation of Reactive Red 4 as an azo textile was investigated in aqueous solution under irradiation showed 68.0% degradation of the dye within 100 min. The experimental enhanced activity compare to pure Fe2O3 can be ascribed to the formation of composite, which was mainly attributable to the transfer of electron and hole to the surface of composite and hinder the electron hole recombination.

  13. Enhanced bioelectricity generation and azo dye treatment in a reversible photo-bioelectrochemical cell by using novel anthraquinone-2,6-disulfonate (AQDS)/MnOx-doped polypyrrole film electrodes.

    PubMed

    Sun, Jian; Cai, Bihai; Xu, Wenjing; Huang, Yu; Zhang, Yaping; Peng, Yenping; Chang, Kenlin; Kuo, Jiahong; Chen, Kufan; Ning, Xunan; Liu, Guoguang; Wang, Yujie; Yang, Zuoyi; Liu, Jingyong

    2017-02-01

    A novel anthraquinone-2,6-disulfonate/MnOx-doped polypyrrole film (AQDS/Mn/PPy) electrode was prepared by one-step electropolymerization method and was used to improve performance of a reversible photo-bioelectrochemical cell (RPBEC). The RPBEC was operated in polarity reversion depended on dark/light reaction of alga Chlorella vulgaris by which sequential decolorization of azo dye and mineralization of decolorization products coupled with bioelectricity generation can be achieved. The results showed that formation of uniform AQDS/Mn/PPy film significantly enhanced electroactive surface area and electrocatalytic activity of carbon electrode. The RPBEC with AQDS/Mn/PPy electrodes demonstrated 77% increases in maximum power and 73% increases in Congo red decolorization rate before polarity reversion, and 198% increases in maximum power and 138% increases in decolorization products mineralization rate after polarity reversion, respectively, compared to the RPBEC with bare electrode. This was resulted from simultaneous dynamics improvement in half-reaction rate of anode and photo-biocathode due to enhanced electron transfer and algal-bacterial biofilm formation.

  14. Fabrication of a TiO2-BDD heterojunction and its application as a photocatalyst for the simultaneous oxidation of an azo dye and reduction of Cr(VI).

    PubMed

    Yu, Hongbin; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

    2008-05-15

    A TiO2-boron doped diamond (TiO2-BDD) heterojunction was employed as a photocatalyst to simultaneously oxidize an azo dye C.I. reactive yellow 15 (RY15) and reduce hexavalent chromium (Cr(VI)). This heterojunction was fabricated first by depositing a BDD film on a Ti sheet in a hot filament chemical vapor deposition reactor, followed by covering a layer of TiO2 in a metal-organic chemical vapor deposition system. The morphology of this heterojunction was characterized by using a scanning electron microscope (SEM). X-ray diffraction (XRD), Raman spectroscopy, and current-voltage (I-V) measurement were used to characterize its structures. Additionally, the characterization of surface photovoltage showed that the TiO2-BDD heterojunction exhibited a higher photovoltage response and a better ability for charge separation than the photocatalyst of TiO2 directly deposited on a Ti sheet (TiO2-Ti). The photocatalytic experiments revealed that the kinetic constants for the oxidation of RY15 and the reduction of Cr(VI) were, respectively, increased by 85 and 71% when the photocatalyst of TiO2-Ti was replaced by the TiO2-BDD heterojunction. Meanwhile, a significant synergy was confirmed in the simultaneous oxidation of RY15 and reduction of Cr(VI). The enhanced photocatalytic ability of the TiO2-BDD composite could be attributed to the heterojunction. The possible photocatalytic mechanism was also discussed.

  15. Enhanced decolorization of azo dye in a small pilot-scale anaerobic baffled reactor coupled with biocatalyzed electrolysis system (ABR-BES): a design suitable for scaling-up.

    PubMed

    Cui, Dan; Guo, Yu-Qi; Lee, Hyung-Sool; Wu, Wei-Min; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2014-07-01

    A four-compartment anaerobic baffled reactor (ABR) incorporated with membrane-less biocatalyzed electrolysis system (BES) was tested for the treatment of azo dye (alizarin yellow R, AYR) wastewater (AYR, 200 mg L(-1); glucose, 1000 mg L(-1)). The ABR-BES was operated without and with external power supply to examine AYR reduction process and reductive intermediates with different external voltages (0.3, 0.5 and 0.7 V) and hydraulic retention times (HRT: 8, 6 and 4h). The decolorization efficiency in the ABR-BES (8h HRT, 0.5 V) was higher than that in ABR-BES without electrolysis, i.e. 95.1 ± 1.5% versus 86.9 ± 6.3%. Incorporation of BES with ABR accelerated the consumption of VFAs (mainly acetate) and attenuated biogas (methane) production. Higher power supply (0.7 V) enhanced AYR decolorization efficiency (96.4 ± 1.8%), VFAs removal, and current density (24.1 Am(-3) TCV). Shorter HRT increased volumetric AYR decolorization rates, but decreased AYR decolorization efficiency.

  16. Titania-based molecularly imprinted polymer for sulfonic acid dyes prepared by sol-gel method.

    PubMed

    Li, Man; Li, Rong; Tan, Jin; Jiang, Zi-Tao

    2013-03-30

    A novel titania-based molecularly imprinted polymer (MIP) was synthesized through sol-gel process with sunset yellow (Sun) as template, without use of functional monomer. MIP was used as a solid-phase extraction material for the isolation and enrichment of sulfonic acid dyes in beverages. The results showed that MIP exhibited better selectivity, higher recovery and adsorption capacity for the sulfonic acid dyes compared to the non-imprinted polymer (NIP). MIP presented highest extraction selectivity to Sun when pH less than or equal to 3. The adsorption capacity was 485.9 mg g(-1), which was larger than that of NIP (384.7 mg g(-1)). The better clean-up ability demonstrated the capability of MIP for the isolation and enrichment of sulfonic acid dyes in complicated food samples. The mean recoveries for the sulfonic acid dyes on MIP were from 81.9% to 97.2% in spiked soft drink.

  17. Synthesis of magnetically recyclable MnFe2O4@SiO2@Ag nanocatalyst: Its high catalytic performances for azo dyes and nitro compounds reduction

    NASA Astrophysics Data System (ADS)

    Kurtan, U.; Amir, Md.; Yıldız, A.; Baykal, A.

    2016-07-01

    In this study, magnetically recycable MnFe2O4@SiO2@Ag nanocatalyst (MnFe2O4@SiO2@Ag MRCs) has been synthesized through co-precipition and chemical reduction method. XRD analysis confirmed the synthesis of single phase nanoproduct with crystallite size of 10 nm. VSM measurements showed the superparamagnetic property of the product. Catalytic studies showed that MnFe2O4@SiO2@Ag MRC could catalyze the reduction of the various azo compounds like methyl orange (MO), methylene blue (MB), eosin Y (EY), and rhodamine B (RhB) and also aromatic nitro compounds such as 4-nitrophenol (4-NP), 4-nitroaniline (4-NA) and 2-nitroaniline (2-NA). Moreover, the magnetic nanocatalyst showed an excellent reusability properties that remained unchanged after several cycles. Therefore, MnFe2O4@SiO2@Ag is the potential candidate for the application of organic pollutants for wastewater treatment.

  18. Interaction of toxic azo dyes with heme protein: biophysical insights into the binding aspect of the food additive amaranth with human hemoglobin.

    PubMed

    Basu, Anirban; Kumar, Gopinatha Suresh

    2015-05-30

    A biophysical study on the interaction of the food colorant amaranth with hemoglobin was undertaken. Spectrophotometric and spectrofluorimetric studies proposed for an intimate binding interaction between the dye and the protein. The dye quenched the fluorescence of the protein remarkably and the mechanism of quenching was found to be static in nature. Synchronous fluorescence studies suggested that the polarity around the tryptophan residues was altered in the presence of amaranth whereas the polarity around tyrosine residues remained largely unaltered. 3D fluorescence, FTIR and circular dichroism results suggested that the binding reaction caused conformational changes in hemoglobin. The negative far-UV CD bands exhibited a significantly large decrease in magnitude in the presence of amaranth. From calorimetry studies it was established that the binding was driven by a large positive entropic contribution and a small but favorable enthalpy change.

  19. Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction.

    PubMed

    Vallet, Ana; Ovejero, Gabriel; Rodríguez, Araceli; Peres, José A; García, Juan

    2013-01-15

    Active nickel catalysts (7 wt%) supported over Mg-Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min(-1) and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min(-1), respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T(r)=0.098 g(Ni) min mL(-1). After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T(r)=0.098 g(Ni) min mL(-1), attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity.

  20. In vitro mutagenicity, NMR metabolite characterization of azo and triphenylmethanes dyes by adherents bacteria and the role of the "cna" adhesion gene in activated sludge.

    PubMed

    Ayed, Lamia; Bakir, Karima; Ben Mansour, Hedi; Hammami, Saousen; Cheref, Abdelkrim; Bakhrouf, Amina

    2017-02-01

    Staphylococcus aureus, showing the greatest decolorization ability, was further investigated for Methyl Red (MR) Congo Red (CR), Crystal Violet (CV) and Malachite Green (MG) decolorization using response surface methodology (RSM). The chemometric methods use, based on statistical design of experiments (DOEs) such as RSM is becoming increasingly widespread in several sciences such as analytical chemistry, engineering and environmental chemistry. Stapphylococcus aureus ATCC 25923, Stapphylococcus aureus (S1) and Stapphylococcus aureus (S2), were isolated from textile wastewater plant located in KsarHellal, Tunisia and were tested for their decolorization capacity. PCR technique was utilized to identify the 3 bacterial strains and to detect the adhesin gene "cna". Biodegradation of MR, CR, CV and MG (750 ppm), were investigated under shaking condition in Mineral Salt Medium (MSM) solution at pH 7.5 and temperature 30 °C, using a 3.7 × 10(5) CFU/ml as inoculum size. Our results showed that Staphylococcus aureus had a high decolorization capacity. Nuclear magnetic resonance (NMR) spectroscopy analysis confirmed the biodegradation of dyes. The four dyes mutagenicity with the S9 metabolizing system decreased significantly after biodegradation and totally disappeared. Nuclear magnetic resonance (NMR) spectroscopy analysis confirmed the biodegradation of dyes.

  1. Capacity of a newly isolated fungus Pleurotus eryngii from Tunceli, Ovacik for chemical oxygen demand reduction and biodecolorization of Azo-Dye Congo Red.

    PubMed

    Yildirim, N; Gonen, U

    2015-06-07

    Biodecolorization of Congo red dye in both agar—plate and agitated liquid culture mediums by newly isolated white rot fungus Pleurotus eryngii has been studied. This fungus isolated from Tunceli—Ovacik province of Turkey. We have also examined the chemical oxygen demand reduction after decolorization under agitated liquid culture medium. For agar plate screening the decolorization capacity of P. eryngii, growth and decolorization halos were determined on saboroud dextrose agar (SDA) plates containing 0.05, 0.1, 0.5, 1 and 2 g/l of Congo red. P. eryngii showed certain decolorization capacities and was able to decolorize all studied concentrations of Congo red, but not to the same extent. Our results indicated that the new isolate P. eryngii had maximum decolorization (87% at 100 mg/l initial dye concentration) and chemical oxygen demand reduction (82% at 25 mg/l initial dye concentration) activities after 7 days under agitated submerged culture conditions. This new isolate could be an effective bioremediation tool for treatment of Congo red containing textile wastewater.

  2. Treatment of azo dye-containing wastewater by a Fenton-like process in a continuous packed-bed reactor filled with activated carbon.

    PubMed

    Mesquita, Isabel; Matos, Luís C; Duarte, Filipa; Maldonado-Hódar, F J; Mendes, Adélio; Madeira, Luis M

    2012-10-30

    In this work, oxidation with a Fenton-like process of a dye solution was carried out in a packed-bed reactor. Activated carbon Norit RX 3 Extra was impregnated with ferrous sulfate and used as catalyst (7 wt.% of iron). The effect of the main operating conditions in the Chicago Sky Blue (CSB) degradation was analyzed. It was found that the increase in temperature leads to a higher removal of the dye and an increased mineralization. However, it also increases the iron leaching, but the values observed were below 0.4 ppm (thus, far below European Union limits). It was possible to reach, at steady-state, a dye conversion of 88%, with a total organic carbon (TOC) removal of ca. 47%, being the reactor operated at 50°C, pH 3, W(cat)/Q=4.1 g min mL(-1) (W(cat) is the mass of catalyst and Q the total feed flow rate) and a H(2)O(2) feed concentration of 2.25 mM (for a CSB feed concentration of 0.012 mM). The same performance was reached in three consecutive cycles.

  3. Effect of nucleic acid binding dyes on DNA extraction, amplification, and STR typing.

    PubMed

    Haines, Alicia M; Tobe, Shanan S; Kobus, Hilton J; Linacre, Adrian

    2015-10-01

    We report on the effects of six dyes used in the detection of DNA on the process of DNA extraction, amplification, and detection of STR loci. While dyes can be used to detect the presence of DNA, their use is restricted if they adversely affect subsequent DNA typing processes. Diamond™ Nucleic Acid Dye, GelGreen™, GelRed™, RedSafe™, SYBR(®) Green I, and EvaGreen™ were evaluated in this study. The percentage of dye removed during the extraction process was determined to be: 70.3% for SYBR(®) Green I; 99.6% for RedSafe™; 99.4% for EvaGreen™; 52.7% for Diamond™ Dye; 50.6% for GelRed™, and; could not be determined for GelGreen™. It was then assumed that the amount of dye in the fluorescent quantification assay had no effect on the DNA signal. The presence of all six dyes was then reviewed for their effect on DNA extraction. The t-test showed no significant difference between the dyes and the control. These extracts were then STR profiled and all dyes and control produced full DNA profiles. STR loci in the presence of GelGreen(TM) at 1X concentration showed increased amplification products in comparison to the control samples. Full STR profiles were detected in the presence of EvaGreen™ (1X), although with reduced amplification products. RedSafe™ (1X), Diamond™ Dye (1X), and SYBR(®) Green I (1X) all exhibited varying degrees of locus drop-out with GelRed™ generating no loci at all. We provide recommendations for the best dye to visualize the presence of DNA profile as a biological stain and its subsequent amplification and detection.

  4. Removal of textile dyes and metallic ions using polyelectrolytes and macroelectrolytes containing sulfonic acid groups.

    PubMed

    Caldera Villalobos, M; Peláez Cid, A A; Herrera González, Ana M

    2016-07-15

    This work reports the removal of textile dyes and metallic ions by means of adsorption and coagulation-flocculation using two polyelectrolytes and two macroelectrolytes containing sulfonic acid groups. The adsorption of textile dyes was studied in aqueous solutions containing cationic dyes and in wastewater containing a vat dye. Also, removal of vat and naphthol dyes was studied using the process of coagulation-flocculation. The results show these materials possess elevated adsorption capacity, and they accomplished removal rates above 97% in aqueous solutions. The removal of the vat dye improved the quality of the wastewater notably, and an uncolored effluent was obtained at the end of the treatment. The treatment using adsorption decreased the values for coloration, conductivity, suspended solids, and pH. The removal of vat and naphthol dyes by means of coagulation-flocculation was studied as well, and removal rates of 90% were obtained. The polyelectrolytes and macroelectrolytes also proved effective in the adsorption of metallic ions in wastewater. The treatment using adsorption accomplished high removal rates of metallic ions, and it showed greater selectivity towards Cu(2+), Fe(3+) and Pb(2+). A decrease in the content of solids as well as the values for COD and conductivity was observed in the wastewater as well. The analyses of FT-IR indicated that cationic dyes and metallic ions were chemisorbed by means of ionic exchange.

  5. A study of effects of acid activated saw dust on the removal of different dissolved tannery dyes (acid dye) from aqueous solutions.

    PubMed

    Dhar, N R; Khoda, A K M B; Khan, A H; Bala, P; Karim, M F

    2005-04-01

    The effectiveness of acid activated sawdust in absorbing D-Brown EGP and Lurazol Brown PM dyes from aqueous solutions was studied as a function of agitation time and initial dye concentration. The experimental data were fitted to Langmuir and Freundlich isotherm and found that adsorption process follows both the isotherms. The values of Langmuir and Freundlich constants indicate favorable and beneficial adsorption. Saw dust is an excellent low cost adsorbent of colored organic anions and may have significant potential as a color removal from tannery wastewater.

  6. A highly efficient immobilized ZnO/Zn photoanode for degradation of azo dye Reactive Green 19 in a photocatalytic fuel cell.

    PubMed

    Lee, Sin-Li; Ho, Li-Ngee; Ong, Soon-An; Wong, Yee-Shian; Voon, Chun-Hong; Khalik, Wan Fadhilah; Yusoff, Nik Athirah; Nordin, Noradiba

    2017-01-01

    Photocatalytic fuel cell (PFC) is a potential wastewater treatment technology that can generate electricity from the conversion of chemical energy of organic pollutants. An immobilized ZnO/Zn fabricated by sonication and heat attachment method was applied as the photoanode and Pt/C plate was used as the cathode of the PFC in this study. Factors that affect the decolorization efficiency and electricity generation of the PFC such as different initial dye concentrations and pH were investigated. Results revealed that the degradation of Reactive Green 19 (RG19) was enhanced in a closed circuit PFC compared with that of a opened circuit PFC. Almost 100% decolorization could be achieved in 8 h when 250 mL of 30 mg L(-1) of RG19 was treated in a PFC without any supporting electrolyte. The highest short circuit current of 0.0427 mA cm(-2) and maximum power density of 0.0102 mW cm(-2) was obtained by PFC using 30 mg L(-1) of RG19. The correlation between dye degradation, conductivity and voltage output were also investigated and discussed.

  7. Magnetic Mn substituted cobalt zinc ferrite systems: Structural, electrical and magnetic properties and their role in photo-catalytic degradation of methyl orange azo dye

    NASA Astrophysics Data System (ADS)

    Bhukal, Santosh; Bansal, S.; Singhal, Sonal

    2014-07-01

    The present work focuses on the effect of replacement of Fe3+ ions by the Mn3+ ions in cobalt zinc ferrites (Co0.6Zn0.4MnxFe2-xO4 (0.2, 0.4, 0.6, 0.8 and 1.0) on the structural, magnetic, electrical and catalytic properties. Powder X-ray diffraction studies confirmed that all the samples possessed cubic spinel structure with Fd-3m space groups. The saturation magnetization was found to decrease with increase in Mn3+ ions concentration. The drift mobility of all compositions was found to decrease with increase in temperature which could be attributed to the semiconductor nature of nanoferrites. The photo-catalytic activity of all the nanoferrites was evaluated by the degradation of methyl orange dye and it was observed that the degradation of methyl orange dye was enhanced with increase in Mn3+ ions concentration from 0.2 to 1.0. This might be due to the octahedral site preference and higher redox potential of manganese ion as compared those of iron.

  8. Combined cation-exchange and solid phase extraction for the selective separation and preconcentration of zinc, copper, cadmium, mercury and cobalt among others using azo-dye functionalized resin.

    PubMed

    Chatterjee, Mousumi; Srivastava, Bhavya; Barman, Milan K; Mandal, Bhabatosh

    2016-04-01

    A facile synthesis of an ion exchange material (FSG-PAN) has been achieved by functionalizing silica gel with an azo-dye. Its composition and structure are well assessed by systematic analysis. Extractor possesses high BET surface area (617.794m(2)g(-1)), exchange capacity and break-through capacity (BTC) (Q0 Zn(II): 225; Cd(II): 918; Hg(II): 384, Cu(II): 269 and Co(II): 388μMg(-1)). The sorption process was endothermic (+ΔH), entropy-gaining (+ΔS) and spontaneous (-ΔG) in nature. Preconcentration factor has been optimized at 172(Zn(II)); 157.2(Cd(II)); 193.6(Hg(II)); 176(Cu(II)); 172.4(Co(II)). Density functional theory calculation has been performed to analyze the sorption pathway. BTC (μMg(-1)) of FSG-PAN was found to be the product of its frontier orbitals and state of sorbed metal ion species, x (at x=1, mononuclear and x>1, a polynuclear species; i.e., BTC=[amount of HOMO]×x). FSG-PAN is used for the selective separation and preconcentration of Zn(II), Cd(II), Hg(II), Cu(II),Co(II) from large volume sample (800mL) of low concentration (0.017-0.40mML(-1)) in presence of foreign ions (50-300mML(-1)) at optimum conditions (pH: 7.0±1.5, flow rate: 2.5mLmin(-1), temperature: 27°C, equilibration-time: 5min). The method was found to be effective for real samples also.

  9. Dye-sensitized solar cells using retinoic acid and carotenoic acids: Dependence of performance on the conjugation length and the dye concentration

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Feng; Fujii, Ritsuko; Ito, Seigo; Koyama, Yasushi; Yamano, Yumiko; Ito, Masayoshi; Kitamura, Takayuki; Yanagida, Shozo

    2005-11-01

    Titanium oxide-based dye-sensitized solar cells (DSSC) were fabricated by the use of retinoic acid and carotenoic acids having the number of conjugated double bonds, n = 5-13. The incident photon-to-current conversion efficiency, the photocurrent density and the solar energy-to-electricity conversion efficiency exhibited the highest values at n = 7, and then decreased toward both sides. The effects of dilution of CA7 with deoxycholic acid were also examined. The above parameters per unit CA7 concentration progressively increased toward the lowest concentration, which is ascribed to the isolated excitation free from singlet-triplet annihilation in the dye molecules on the TiO 2 layer.

  10. Molecularly imprinted polymers for some reactive dyes.

    PubMed

    Okutucu, Burcu; Akkaya, Alper; Pazarlioglu, Nurdan Kasikara

    2010-01-01

    Depending upon their structure, azo- and anthraquinonic dyes are the two major classes and together represent 90% of all organic colorants. Adsorption of dye molecules onto a sorbent can be an effective, low-cost method of color removal. Most of the techniques used for removal of dyes are of high production cost, and the regeneration also makes them uneconomical. There is much interest in the development of cheaper and effective newer materials for use as adsorbents. Molecular imprinting is a new kind of materials that can be alternative adsorbents. In this study, molecularly imprinted polymers of three textile dyes (Cibacron Orange P-4R, Cibacron Red P-4B, Cibacron Black PSG) were prepared. Methacrylic acid was used as a monomer for red and orange dyes and acrylamide was used for black dye. Methanol:acetonitrile was used as a porogen. The selective recognition ability of the molecularly imprinted polymers was studied by an equilibrium-adsorption batch method. The adsorption data are for Cibacron Black PSG 65% and nonimprinted polymer (NIP) 25%; Cibacron Red P-4B 72% and NIP 18%; and Cibacron Orange P-4R 45% and NIP 10%, respectively. Dye-imprinted polymers were used as a solid-phase extraction material for selective adsorption from wastewater of textile factory.

  11. Response surface optimization of bioremediation of Acid black 52 (Cr complex dye) using Aspergillus tamarii.

    PubMed

    Ghosh, Arpita; Dastidar, Manisha Ghosh; Sreekrishnan, T R

    2017-02-01

    Bioremediation of the Cr complex dye (Acid black 52) was performed in batch and continuous modes using growing Aspergillus tamarii. The removal of Cu which may be present as an impurity was 100% at 100 mg/L initial dye concentration. The removal of color and Cr decreased from 87% to 4% and from 92% to 8%, respectively, by increasing dye concentration from 100 to 5000 mg/L in batch mode. The removal of color and Cr increased from 27% to 67.8% and from 32% to 72%, respectively, with increasing hydraulic retention time from 28 to 220 h at 100 mg/L dye concentration in continuous mode. For optimization of color removal using response surface methodology (RSM) the ranges of parameters were kept at dye concentration: 200-500 mg/L; pH: 4-6 and time: 35-50 hours. Maximum color removal suggested by the model was 85.6809% at initial dye concentration 200 mg/L, pH 5.25 and time 50 h. The validation experiments in batch and continuous modes were conducted at the optimum conditions as suggested by the RSM model. The theoretical and experimental responses of color removal were in close agreement in batch mode. The scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy and gas chromatography-mass spectroscopy analyses indicated biosorption and biodegradation of dye.

  12. Skin testing of gallic acid-based hair dye in paraphenylenediamine/paratoluenediamine-reactive patients.

    PubMed

    Choi, Yunseok; Lee, Joon Ho; Kwon, Hyok Bu; An, Susun; Lee, Ai-Young

    2016-07-01

    Incidence of allergic contact dermatitis (ACD) to para-phenylenediamine (PPD)/paratoluenediamine (PTD) hair dyes is increasing. Hair dyes utilizing gallic acid (GA) may be a safe alternative. However, pretesting is recommended. We investigated the contact sensitivity to ingredients of a dye product; GA, monoethanolamine thioglycolate (MT), l-cystein and ferrous sulfate, and an appropriate pretest method in 31 patients reactive to PPD and/or PTD. An open test was performed with the test dye following the patch test. Subsequently, a use test was performed twice, with a 4-week interval. One subject showed a positive reaction to ferrous sulfate in the patch test. Another subject reacted to the first compound alone in the open test. Thirteen subjects manifesting cutaneous lesions from previous regular hair dyeing, showed reactions at the first use of the test dye; and six had reactions with reduced severity at the second test. GA and MT are safe for use in ACD patients reactive to PPD and/or PTD. For predicting contact allergy to hair dyes, the open test appeared to be a better pretest method than the patch test.

  13. Degradation of acid blue 40 dye solution and dye house wastewater from textile industry by photo-assisted electrochemical process.

    PubMed

    Moraes, Peterson B; Pelegrino, Rosangela R L; Bertazzoli, Rodnei

    2007-12-01

    In this paper, electrochemical and photo-assisted electrochemical processes are used for color, total organic carbon (TOC) and chemical oxygen demand (COD) degradation of one of the most abundant and strongly colored industrial wastewaters, which results from the dyeing of fibers and fabrics in the textile industry. The experiments were carried out in an 18 L pilot-scale tubular flow reactor with 70%TiO(2)/30%RuO(2) DSA. A synthetic acid blue 40 solution and real dye house wastewater, containing the same dye, were used for the experiments. By using current density of 80 mA cm(-2) electrochemical process has the capability to remove 80% of color, 46% of TOC and 69% of COD. When used the photochemical process with 4.6 mW cm(-2) of 254 nm UV-C radiation to assist the electrolysis, has been obtained 90% of color, 64% of TOC and 60% of COD removal in 90 minutes of processing; furthermore, 70% of initial color was degraded within the first 15 minutes. Experimental runs using dye house wastewater resulted in 78% of color, 26% of TOC and 49% of COD in electrolysis at 80 mA cm(-2) and 90 min; additionally, when photo-assisted, electrolysis resulted in removals of 85% of color, 42% of TOC and 58% of COD. For the operational conditions used in this study, color, TOC and COD showed pseudo-first-order decaying profiles. Apparent rate constants for degradation of TOC and COD were improved by one order of magnitude when the photo-electrochemical process was used.

  14. pH-sensitive Itaconic acid based polymeric hydrogels for dye removal applications.

    PubMed

    Sakthivel, M; Franklin, D S; Guhanathan, S

    2016-12-01

    A series of Itaconic Acid (IA) based pH-sensitive polymeric hydrogels were synthesized by condensation polymerization of Itaconic Acid (IA) with Ethylene Glycol (EG) in the presence of an acid medium resulted into pre-polymer. Further, pre-polymer were co-polymerized with Acrylic Acid (AA) through free radical polymerization using Potassium persulphate (KPS). The structural and surface morphological characterizations of the synthesized hydrogels were studied using FT-IR spectroscopy and Scanning Electron Microscope (SEM) respectively. The swelling and swelling equilibrium were performed at varies pH (4.0-10.0). Further, the effects of IA, EG and AA on swelling properties have also been investigated. Thermal stability of synthesized hydrogels have been investigated by TGA, DTA and DSC. The synthesized hydrogels have shown good ability to uptake a Cationic dye. The Methylene blue has been chosen as a model cationic dye. The results of dye removal using IA hydrogels found to have excellent dye removal capacity. Such kind of IA based hydrogels may be recommended for eco-friendly environmental application. viz., removal of dyes and metal ions and sewage water treatment, purification of water etc.

  15. A method for concentrating organic dyes: colorimetric measurements of nitric oxides and sialic acids.

    PubMed

    Lalezari, Parviz; Lekhraj, Rukmani; Casper, Diana

    2011-09-01

    A new method for extraction and concentration of organic dyes that uses a reagent composed of a nonionic detergent mixed with an alcohol is described. We have observed that water-soluble organic dyes are also soluble in nonionic detergents and can be extracted by adding salt, which separates the dye-detergent component from the aqueous phase. We have also found that mixing nonionic detergents with alcohols markedly reduces their viscosity and produces stable, free-flowing, and effective reagents for color extraction. On the basis of these observations, we used a mixture of Triton X-100 and 1-butanol and observed that water-soluble natural and synthetic chromophores, as well as dyes generated in biochemical reactions, can be extracted, concentrated, and analyzed spectrophotometrically. Trypan blue and phenol red are used as examples of synthetic dyes, and red wine is used as an example of phenolic plant pigments. Applications for quantification of nitric oxides and sialic acids are described in more detail and show that as little as 0.15 nmol of nitric oxide and 0.20 nmol of sialic acid can be detected. A major advantage of this method is its ability to concentrate chromophores from dye-containing solutions that otherwise cannot be measured because of their low concentrations.

  16. Dyeing wool and cotton fibres with acidic extract of Hibiscus rosa sinensis flower.

    PubMed

    Hayat, Lamya; Jacob, Dangly Ann

    2016-05-02

    The focus of this work is to extract a natural dye for colouring camel wool as a substitute for synthetic dyes used in the Sadu House of Kuwait. Their target is to keep the tradition of tent and rug production natural in all its manifestations. Therefore, our task was to find an abundant source that provides a colour preferably red to purple. Hibiscus rosa sinensis (HRS) is an abundantly available plant in Kuwait that was explored for extraction of the red dye to colour camel wool permanently. The powdered petals of red flowers of HRS was extracted with 5% acetic acid which yielded a deep red colour that showed a great potential for woollen fibre dyeing. The use of mordants like alum and some metal salts manifested a wide range of fixed colours which intensified at 85 °C. The colours produced had excellent fastness and was accepted by the Sadu House.

  17. Enhanced photocatalytic efficiency of NiS/TiO{sub 2} composite catalysts using sunset yellow, an azo dye under day light illumination

    SciTech Connect

    Rajamanickam, D.; Dhatshanamurthi, P.; Shanthi, M.

    2015-01-15

    Highlights: • NiS/TiO{sub 2} was successfully synthesized by sol–gel method. • This new method of preparation gives a homogeneous dispersion of NiS on TiO{sub 2}. • Degradation activity of NiS/TiO{sub 2} is found to be more efficient than other catalysts. • Addition of oxidants enhances the degradation efficiency significantly. • COD measurements reveal the complete mineralization of dye molecules. • The catalyst is found to be reusable. - Abstract: To improve the solar light induced photocatalytic application performances of TiO{sub 2}, in this study, the NiS modified TiO{sub 2} composite photocatalysts with various ratios of NiS to TiO{sub 2} were prepared by sol–gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (B–E–T) surface area measurement methods. The photocatalytic activity of NiS/TiO{sub 2} was investigated for the degradation of sunset yellow (SY) in aqueous solution using solar light. The NiS/TiO{sub 2} is found to be more efficient than prepared TiO{sub 2} and TiO{sub 2}–P25 at pH 7 for the mineralization of SY. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The degradation was strongly enhanced in the presence of oxidants such as H{sub 3}K{sub 5}O{sub 18}S{sub 4} (Oxone), KIO{sub 4}, and KBrO{sub 3}. The mineralization of SY has been identified by COD measurements. The catalyst is found to be reusable.

  18. Preparation and characterization of SeO2/TiO2 composite photocatalyst with excellent performance for sunset yellow azo dye degradation under natural sunlight illumination

    NASA Astrophysics Data System (ADS)

    Rajamanickam, D.; Dhatshanamurthi, P.; Shanthi, M.

    2015-03-01

    To improve the solar light induced photocatalytic application performances of TiO2, in this study, the SeO2 modified TiO2 composite photocatalysts with various ratios of SeO2 to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of SeO2/TiO2 was investigated for the degradation of sunset yellow (SY) in aqueous solution using solar light. The SeO2/TiO2 is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The degradation was strongly enhanced in the presence of electron acceptors such as oxone, KIO4 and KBrO3. The kinetics of SY photodegradation was found to follow the pseudo-first order rate law and could be described in terms of Langmuir-Hinshelwood model. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

  19. Synthesis and spectral study of new azo dye and its iron complexes derived from 2-naphthol and 2-amino-3-hydroxypyridine

    SciTech Connect

    G, Vidya V. Sadasivan, V.; Meena, S. S. Bhatt, Pramod

    2014-10-15

    An azodye C{sub 5}H{sub 12}N{sub 3}O{sub 2} [LH] is synthesised by coupling diazotised 2-amino-3-hydroxy pyridine with 2-naphthol in ice cold condition. The Fe(II)and Fe(III) complexes were prepared by mixing ethanol solution of metal salt and azodye in 1:2 molar ratio. The dye and metal complexes are structurally characterised by elemental analysis, molar conductance, magnetic susceptibility measurements and spectral techniques like IR, UV-Vis, and Mössbauer analysis. Analytical data suggests the stoichiometry as [FeL{sub 2}Cl(H{sub 2}O)] for Fe(III) complex and [FeL{sub 2}(H{sub 2}O)] for Fe(II) complex. The IR spectral data suggests that [L{sup −}] is acting as a uninegative bidentate ligand. A high spin octahedral geometry is tentatively proposed for both the complexes with respect to the above studies.

  20. Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts

    NASA Astrophysics Data System (ADS)

    Rajamanickam, D.; Shanthi, M.

    2014-07-01

    The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

  1. Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts.

    PubMed

    Rajamanickam, D; Shanthi, M

    2014-07-15

    The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

  2. Preparation and characterization of SeO2/TiO2 composite photocatalyst with excellent performance for sunset yellow azo dye degradation under natural sunlight illumination.

    PubMed

    Rajamanickam, D; Dhatshanamurthi, P; Shanthi, M

    2015-03-05

    To improve the solar light induced photocatalytic application performances of TiO2, in this study, the SeO2 modified TiO2 composite photocatalysts with various ratios of SeO2 to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of SeO2/TiO2 was investigated for the degradation of sunset yellow (SY) in aqueous solution using solar light. The SeO2/TiO2 is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The degradation was strongly enhanced in the presence of electron acceptors such as oxone, KIO4 and KBrO3. The kinetics of SY photodegradation was found to follow the pseudo-first order rate law and could be described in terms of Langmuir-Hinshelwood model. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

  3. High flux and antifouling properties of negatively charged membrane for dyeing wastewater treatment by membrane distillation.

    PubMed

    An, Alicia Kyoungjin; Guo, Jiaxin; Jeong, Sanghyun; Lee, Eui-Jong; Tabatabai, S Assiyeh Alizadeh; Leiknes, TorOve

    2016-10-15

    This study investigated the applicability of membrane distillation (MD) to treat dyeing wastewater discharged by the textile industry. Four different dyes containing methylene blue (MB), crystal violet (CV), acid red 18 (AR18), and acid yellow 36 (AY36) were tested. Two types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) were used. The membranes were characterized by testing against each dye (foulant-foulant) and the membrane-dye (membrane-foulant) interfacial interactions and their mechanisms were identified. The MD membranes possessed negative charges, which facilitated the treatment of acid and azo dyes of the same charge and showed higher fluxes. In addition, PTFE membrane reduced the wettability with higher hydrophobicity of the membrane surface. The PTFE membrane evidenced especially its resistant to dye absorption, as its strong negative charge and chemical structure caused a flake-like (loose) dye-dye structure to form on the membrane surface rather than in the membrane pores. This also enabled the recovery of flux and membrane properties by water flushing (WF), thereby direct-contact MD with PTFE membrane treating 100 mg/L of dye mixtures showed stable flux and superior color removal during five days operation. Thus, MD shows a potential for stable long-term operation in conjunction with a simple membrane cleaning process, and its suitability in dyeing wastewater treatment.

  4. Third-order nonlinear optical properties of acid green 25 dye by Z-scan method

    NASA Astrophysics Data System (ADS)

    Jeyaram, S.; Geethakrishnan, T.

    2017-03-01

    Third-order nonlinear optical (NLO) properties of aqueous solutions of an anthraquinone dye (Acid green 25 dye, color index: 61570) have been studied by Z-scan method with a 5 mW continuous wave (CW) diode laser operating at 635 nm. The nonlinear refractive index (n2) and the absorption coefficient (β) have been evaluated respectively from the closed and open aperture Z-scan data and the values of these parameters are found to increase with increase in concentration of the dye solution. The negative sign of the observed nonlinear refractive index (n2) indicates that the aqueous solution of acid green 25 dye exhibits self-defocusing type optical nonlinearity. The mechanism of the observed nonlinear absorption (NLA) and nonlinear refraction (NLR) is attributed respectively to reverse saturable absorption (RSA) and thermal nonlinear effects. The magnitudes of n2 and β are found to be of the order of 10-7 cm2/W and 10-3 cm/W respectively. With these experimental results, the authors suggest that acid green 25 dye may have potential applications in nonlinear optics.

  5. Analysis of acid-generating action of PAG in an EUV resist using acid-sensitive dyes

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Atsushi; Matsumoto, Yoko; Biafore, John J.

    2013-03-01

    Researchers are currently examining various methods for determining the quantity of acid generated by a photoacid generator (PAG) and for analyzing acid-generating reactions using acid-sensitive dyes that react with acid and generate a color. Adding an acid-sensitive dye to the resist gives a clear grasp of the acid-generating action. The process involves applying a resist containing an acid-sensitive dye to a quartz substrate; exposing the substrate; and measuring and evaluating the absorbance of a chromogenic substance near 530 nm using a spectroscope. The method determines the rate constant for acid generation (Dill C parameter) during exposure based on the relationship between transmissivity at 530 nm and exposure dose. Using this method, we obtained and compared rate constants for acid generation (C parameters) as part of our study of dependence on the quantity of quencher in the EUV resist. Our results indicate a new model that accounts for the quencher concentration parameter would be useful in analyzing dependence on the quantity of quencher. This paper presents these findings, together with the results of studies of profile simulations using the quencher concentration parameter obtained in the experiments.

  6. Photofabrication of surface relief gratings using post functionalized azo polymers

    SciTech Connect

    Tripathy, S.K.; Kumar, J.; Kim, D.Y.; Jiang, X.; Wang, X.; Li, L.; Sukwattanasinitt, M.; Sandman, D.J.

    1998-07-01

    A series of azobenzene funtionalized polymers has been synthesized by post polymerization azo coupling reaction. Photo-fabrication of surface relief gratings were studied on the polymer films. Epoxy based azo polymers were prepared by post azo coupling reaction to form polymers containing donor-acceptor type azo chromophores. The azo chromophores were designed to contain ionizable groups to impart self-assembling and photoprocessing capabilities to the polymers. The polymers containing 4-(4-(carboxylic acid)phenylazo)aniline chromophores can be directly photofabricated to form surface relief gratings with large surface modulations. Charge interactions had a strong influence on the details of the writing process. A new soluble polydiacetylene, post-functionalized with azobenzene groups was also prepared. Large amplitude surface gratings could be fabricated on this polydiacetylene film as well.

  7. Adsorption of acid dyes from aqueous solution on activated bleaching earth.

    PubMed

    Tsai, W T; Chang, C Y; Ing, C H; Chang, C F

    2004-07-01

    In the present study, activated bleaching earth was used as clay adsorbent for an investigation of the adsorbability and adsorption kinetics of acid dyes (i.e., acid orange 51, acid blue 9, and acid orange 10) with three different molecular sizes from aqueous solution at 25 degrees C in a batch adsorber. The rate of adsorption has been investigated under the most important process parameters (i.e., initial dye concentration). A simple pseudo-second-order model has been tested to predict the adsorption rate constant, equilibrium adsorbate concentration, and equilibrium adsorption capacity by the fittings of the experimental data. The results showed that the adsorbability of the acid acids by activated bleaching earth follows the order: acid orange 51 > acid blue 9 > acid orange 10, parallel to the molecular weights and molecular sizes of the acid dyes. The adsorption removals (below 3%) of acid blue 9 and acid orange 10 onto the clay adsorbent are far lower than that (approximately 24%) of acid orange 51. Further, the adsorption kinetic of acid orange 51 can be well described by the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir model appears to fit the adsorption better than the Freundlich model. The external coefficients of mass transfer of the acid orange 51 molecule across the boundary layer of adsorbent particle have also been estimated at the order of 10(-4)-10(-5) cm s(-1) based on the film-pore model and pseudo-second-order reaction model.

  8. Acid Black 48 dye biosorption using Saccharomyces cerevisiae immobilized with treated sugarcane bagasse.

    PubMed

    Mitter, E K; Corso, C R

    2012-01-01

    The textile industry consumes large quantities of water and chemicals, especially in dyeing and finishing processes. Textile dye adsorption can be accomplished with natural or synthetic compounds. Cell immobilization using biomaterials allows the reduction of toxicity and mechanical resistance and opens spaces within the matrix for cell growth. The use of natural materials, such as sugarcane bagasse, is promising due to the low costs involved. The aim of the present study was to evaluate the use of sugarcane bagasse treated with either polyethyleneimine (PEI), NaOH or distilled water in the cell immobilization of Saccharomyces cerevisiae for textile dye removal. Three different adsorption tests were conducted: treated sugarcane bagasse alone, free yeast cells and bagasse-immobilized yeast cells. Yeast immobilization was 31.34% with PEI-treated bagasse, 8.56% with distilled water and 22.54% with NaOH. PEI-treated bagasse exhibited the best removal rates of the dye at all pH values studied (2.50, 4.50 and 6.50). The best Acid Black 48 adsorption rates were obtained with use of free yeast cells. At pH 2.50, 1 mg of free yeast cells was able to remove 5488.49 g of the dye. The lowest adsorption capacity rates were obtained using treated bagasse alone. However, the use of bagasse-immobilized cells increased adsorption efficiency from 20 to 40%. The use of immobilized cells in textile dye removal is very attractive due to adsorbed dye precipitation, which eliminates the industrial need for centrifugation processes. Dye adsorption using only yeast cells or sugarcane bagasse requires separation methods.

  9. Membrane-Inspired Acidically Stable Dye-Sensitized Photocathode for Solar Fuel Production.

    PubMed

    Click, Kevin A; Beauchamp, Damian R; Huang, Zhongjie; Chen, Weilin; Wu, Yiying

    2016-02-03

    Tandem dye-sensitized photoelectrochemical cells (DSPECs) for water splitting are a promising method for sustainable energy conversion but so far have been limited by their lack of aqueous stability and photocurrent mismatch between the cathode and anode. In nature, membrane-enabled subcellular compartmentation is a general approach to control local chemical environments in the cell. The hydrophobic tails of the lipid make the bilayer impermeable to ions and hydrophilic molecules. Herein we report the use of an organic donor-acceptor dye that prevents both dye desorption and semiconductor degradation by mimicking the hydrophobic/hydrophilic properties of lipid bilayer membranes. The dual-functional photosensitizer (denoted as BH4) allows for efficient light harvesting while also protecting the semiconductor surface from protons and water via its hydrophobic π linker. The protection afforded by this membrane-mimicking dye gives this system excellent stability in extremely acidic (pH 0) conditions. The acidic stability also allows for the use of cubane molybdenum-sulfide cluster as the hydrogen evolution reaction (HER) catalyst. This system produces a proton-reducing current of 183 ± 36 μA/cm(2) (0 V vs NHE with 300 W Xe lamp) for an unprecedented 16 h with no degradation. These results introduce a method for developing high-current, low-pH DSPECs and are a significant move toward practical dye-sensitized solar fuel production.

  10. A Three-Component Assembly Promoted by Boronic Acids Delivers a Modular Fluorophore Platform (BASHY Dyes).

    PubMed

    Santos, Fábio M F; Rosa, João N; Candeias, Nuno R; Carvalho, Cátia Parente; Matos, Ana I; Ventura, Ana E; Florindo, Helena F; Silva, Liana C; Pischel, Uwe; Gois, Pedro M P

    2015-12-22

    Invited for the cover of this issue are Uwe Pischel, Pedro Gois and co-workers at the Universities of Huelva and Lisbon. The image depicts a puzzle, which symbolizes the multicomponent reaction used to prepare a series of boronic acid salicylidenehydrazone (BASHY) dyes that are applied in cell staining. Read the full text of the article at 10.1002/chem.201503943.

  11. Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

    ERIC Educational Resources Information Center

    Clark, Daniel D.

    2007-01-01

    Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

  12. An NMR study of merocyanine-type dyes derived from barbituric acid.

    PubMed

    Rezende, Marcos Caroli; Flores, Patricio; Guerrero, Juan; Villarroel, Luis

    2004-06-01

    The 13C NMR of two solvatochromic dyes derived from a barbituric acid acceptor and dimethylaminophenyl donor fragments, compound 1 and the related merocyanine 2, were recorded in various solvents. The observed chemical-shift variations were used to interpret their structural differences and solvatochromic behavior in solution.

  13. Successful treatment of high azo dye concentration wastewater using combined anaerobic/aerobic granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR): simultaneous adsorption and biodegradation processes.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    The application of a granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR) for treatment of wastewater containing 1,000 mg/L Acid Red 18 (AR18) was investigated in this research. The treatment system consisted of a sequencing batch reactor equipped with moving GAC as biofilm support. Each treatment cycle consisted of two successive anaerobic (14 h) and aerobic (8 h) reaction phases. Removal of more than 91% chemical oxygen demand (COD) and 97% AR18 was achieved in this study. Investigation of dye decolorization kinetics showed that the dye removal was stimulated by the adsorption capacity of the GAC at the beginning of the anaerobic phase and then progressed following a first-order reaction. Based on COD analysis results, at least 77.8% of the dye total metabolites were mineralized during the applied treatment system. High-performance liquid chromatography analysis revealed that more than 97% of 1-naphthyalamine-4-sulfonate as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase. According to the scanning electron microscopic analysis, the microbial biofilms grew in most cavities and pores of the GAC, but not on the external surfaces of the GAC.

  14. Enhanced adsorption of active brilliant red X-3B dye on chitosan molecularly imprinted polymer functionalized with Ti(IV) as Lewis acid.

    PubMed

    Deng, Hui; Wei, Zhilai; Wang, XiaoNing

    2017-02-10

    A Ti(IV) functionalized chitosan molecularly imprinted polymer (Ti-CSMIP) was successfully prepared. Ti(4+) as Lewis acidic was used to modify chitosan MIP by producing metal hydroxyl group and protonated surface of adsorbent in aqueous solution to recognize X-3B molecule as a Lewis base. The adsorbent was characterized by FTIR, SEM, XRD, BET, elemental and zeta potential analysis. XRD illustrated Ti-CSMIP exhibited a weak anatase phase when Ti(4+) cross-linked with chitosan. Batch adsorption experiments were performed to evaluate adsorption condition, including sorption isotherm, kinetics and reusability. The maximum adsorption capacity of Ti-CSMIP for X-3B was 161.1mg/g at 293K when solution pH was in the range of 6.0-7.0. Equilibrium data was well analyzed by three-parameter isotherm model, and the kinetics of adsorption followed the pseudo-second kinetics equation. Regeneration experiments indicated a possible application as an effective sorbent for the selective removal of azo anionic dye in aqueous solutions.

  15. Degradation of reactive, acid and basic textile dyes in the presence of ultrasound and rare earths [Lanthanum and Praseodymium].

    PubMed

    Srivastava, Pankaj; Goyal, Shikha; Patnala, Prem Kishore

    2014-11-01

    Degradation of five textile dyes, namely Reactive Red 141 (RR 141), Reactive Blue 21 (RB 21), Acid Red 114 (AR 114), Acid Blue 113 (AB 113) and Basic Violet 16 (BV 16) in aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La(3+) and Pr(3+)). Kinetic analysis of the data showed a pseudo-first order degradation reaction for all the dyes. The rate constant (k), half life (t1/2) and the process efficiency (φ) for various processes in degradation of dyes under different experimental conditions have been calculated. The influence of concentrations of dyes (16-40mg/L), pH (5, 7 and 9) and rare earth ion concentration (4, 12 and 20mg/L) on the degradation of dyes have also been studied. The degradation percentage increased with increasing rare earth amount and decreased with increasing concentration of dyes. Both horn and bath type sonicators were used at 20kHz and 250W for degradation. The sonochemical degradation rate of dyes in the presence of rare earths was related to the type of chromophoric groups in the dye molecule. Degradation sequence of dyes was further examined through LCMS and Raman spectroscopic techniques, which confirmed the sonochemical degradation of dyes to non-toxic end products.

  16. Sensitizers containing donor cascade and rhodanine-3-acetic acid moieties for dye-sensitized solar cells

    SciTech Connect

    Wu, Quan-Ping; Zhang, Lu; Liang, Mao; Sun, Zhe; Xue, Song

    2011-01-15

    Three organic dyes with D-{pi}-D-{pi}-A structure based on triarylamine, dimethylarylamine, and rhodanine-3-acetic acid moieties are designed and synthesized. Incorporating thiophene moieties into the system affords sensitizers with high molar extinction coefficients. These dyes were applied into nanocrystalline TiO{sub 2} dye-sensitized solar cells through standard operations. For a typical device the maximal monochromatic incident photon-to-current conversion efficiency (IPCE) can reach 73%, with a short-circuit photocurrent density (J{sub sc}) of 7.3 mA/cm{sup 2}, an open-circuit voltage (V{sub oc}) of 636 mV, and a fill factor (ff) of 0.61, corresponding to an overall conversion efficiency ({eta}) of 2.86%. (author)

  17. 40 CFR 721.10202 - Benzoic acid, 4-chloro-2- [(substituted)azo]-, strontium salt (1:1) (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid, 4-chloro-2- -, strontium... New Uses for Specific Chemical Substances § 721.10202 Benzoic acid, 4-chloro-2- -, strontium salt (1:1... identified generically as benzoic acid, 4-chloro-2- -, strontium salt (1:1) (PMN P-08-701) is subject...

  18. 40 CFR 721.10202 - Benzoic acid, 4-chloro-2- [(substituted)azo]-, strontium salt (1:1) (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 4-chloro-2- -, strontium... New Uses for Specific Chemical Substances § 721.10202 Benzoic acid, 4-chloro-2- -, strontium salt (1:1... identified generically as benzoic acid, 4-chloro-2- -, strontium salt (1:1) (PMN P-08-701) is subject...

  19. 40 CFR 721.10202 - Benzoic acid, 4-chloro-2- [(substituted)azo]-, strontium salt (1:1) (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid, 4-chloro-2- -, strontium... New Uses for Specific Chemical Substances § 721.10202 Benzoic acid, 4-chloro-2- -, strontium salt (1:1... identified generically as benzoic acid, 4-chloro-2- -, strontium salt (1:1) (PMN P-08-701) is subject...

  20. 40 CFR 721.10202 - Benzoic acid, 4-chloro-2- [(substituted)azo]-, strontium salt (1:1) (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid, 4-chloro-2- -, strontium... New Uses for Specific Chemical Substances § 721.10202 Benzoic acid, 4-chloro-2- -, strontium salt (1:1... identified generically as benzoic acid, 4-chloro-2- -, strontium salt (1:1) (PMN P-08-701) is subject...