Due to the toxicity, mutagenicity and carcinogenicity of azo dyes and their breakdown products, their removal from industrial wastewaters has been an urgent challenge. In this study, heterogeneous photocatalysis using zno. Pdf degradation of an azo dye using the green macroalga. It is also observed that the time required for azo dye degradation by the present method is about ten times less than the reported methods. The degradation of azo dye with different cathode and. Photocatalytic degradation of commercial textile azo dye. An effective treatment is necessary for the degradation of harmful dye, which is discharged into the surface waters. Degradation of azo dyes by alcaligenes aquatilis 3c and its potential. Aerobic degradation of the azo dye acid red 151 in a sequencing batch bio. The reduction of the azo dye is usually nonspecific and decolorization is faster during the bacterial degradation process. Searching for more efficient light sources is a way to improve aops efficiency. Veluru sri devi, padala sai vikas reddy published on 20191123 download full article with reference data and citations. Degradation of azo dyes by laccase and ultrasound treatment. Degradation of synthetic azo dyes of textile industry.
Azo dyes are used in different industries, including textiles, cosmetics, paper, leather, pharmaceuticals, and food, with an annual consumption of about 0. Photocatalytic degradation of an azo dye, acid red 27, in. The color differences are caused by different substituents on the aromatic rings which lead to differences in the extent of conjugation of the. The resultant samples were characterized by different techniques, such as xrd, sem, and edx. Attempts of identifying the bacteria that may degrade the azo dye has been started back in 1970 with the isolation of three strains, viz. The geometries for two experimentally proposed reaction pathways regarding the cleavage of the c. Saturation mutagenesis to improve the degradation of azo. Dhandayuthapani2 and mazher sultana3 1department of zoology, manonmanium sundaranar university, tirunalvalli, tamil nadu, india. Bacterial decolorization and degradation of azo dyes under certain environmental conditions has gained momentum as a method of treatment, as these are inexpensive, ecofriendly and can be applied. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange mo was.
Dyes may also significantly affect photosynthetic activity in aquatic life by reducing light penetration intensity and may also be toxic to some aquatic fauna and flora due to the presence of aromatics, metals. N bonds for cl and ch3substituted azo dye 44sulfophenylazophenol. Biochemical tests were carried out and identified as bacillus species. This class of dyes gives off bold colors in a variety of hues. Even the most stubborn dyes such as azo dyes can be eliminated from the colored wastewater by our approach. By releasing of azo dye through textile effluent, textile industry is the main cause of water pollution resulting into acute effect on environment. This study focused on the efficiency of removal decolourization. Pdf biodegradation of azo dye compounds researchgate. Degradation azo dyes by environmental microorganisms and. The measurement of concentration of azo dye is as the above, the measurement of total organic carbon toc is carried out by a toc analyzer tocv cph, shimadzu.
The first step in the bacterial degradation of azo dyes, in either anaerobic or aerobic conditions, is the reduction of the n n bond. Degradation of an azo dye using the green macroalga enteromorpha sp. Ongoing investigations focus on the structures of the intermediates formed by laccase and ultrasound to elucidate the degradation. Pdf bacterial decolorization and degradation of azo dyes. 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. Analysis of bacterial degradation of azo dye congo red. The impact of azo dyes in food industry and their degraded products on. Decolorization and degradation of azo dye remazol black b.
Oturan degradation of azo dyes in water by electrofenton process accepted. N bond following the hydroxyl radical addition to the chromophore. As a result of this stability, photolysis is not considered to be a degradation pathway for azo dyes. Bacterial decolourization and degradation of azo dye. Degradation of azo dye acid orange 7 in a microbial. Microbial degradation of azo dyes from textile industry. Dye decoloration and degradation tartrazine azo dye decoloration catalytic advanced oxidation reactions developed by hydrogen link for the decoloration of the dye wastewater result in very effective oxidative degradation of a variety of dyes from food and textile industry effluents. Azo dyes are used in a wide variety of products and can be found in the effluent of most sewage treatment facilities. Rapid degradation of azo dye using mnal powders produced by ballmilling w. The anodic dye degradation products were unstable when exposed to air resulting in regaining of color. Photocatalytic degradation of azo dye orange ii in aqueous.
Decolorization and degradation of azo dye remazol black b by newly isolated pseudomonas putida s. A dye is used to impart color to materials of which it becomes an integral part of. This reduction may involve different mechanisms, such as enzymes, low molecular weight redox mediators, chemical reduction by biogenic reductants like sulfide, or a combination of these. Solution acidity and iron surface area are the factors greatly influencing the degradation rates, and with. In practice, azo dye compounds come in yellows, oranges, reds, browns, and blues. Biodegradation of azo dyes by bacteria inoculated on solid. Photocatalytic degradation of commercial textile azo. Cell wall fragments displaying vp were used for multiple cycles of azo dye degradation. Microbial degradation of synthetic dyes in wastewaters springerlink.
Rapid degradation of azodye using mnal powders produced. Microbial degradation and decolorization of azo dyes has gained more attention recently because of ecofriendly and inexpensive nature. Enhanced sonocatalytic degradation of azo dyes by autio2. It showed that the degradation is a twostep reaction, with the first step being reversible. Mechanistic study of the degradation of azo dye reactive brilliant red k2bp by ultrasound radiation and zerovalent iron. Although most commercially available azo dyes are reds, oranges, and yellows, it is theoretically possible for the entire spectrum to be produced. Anaerobic decolorization of an azo dye by a mixed culture.
The photodegradation process of azo dyes begins when the simulated sunlight lamp is turned on, we take and filter the samples from the photoreactor at different photoreaction time. Decolorization of azo dye by bacteria reductive cleavage of the nn bond is. Biodegradation of azo dyes hatice atacag erkurt springer. The photocatalytic degradation of the chemical dye azo and dye effluents in different time duration has been investigated using biologically synthesized silver nanoparticles. Reduced graphene oxidetio2 can act as photocatalyst for the degradation of methyl orange, azo dye, and pharmaceutical water waste. In order to prolong the lifetime of products dyed with azo dyes, it is essential to ensure stability against microbial attack, and tests have shown that azo dyes biodegrade negligibly in short term tests under aerobic conditions. Biodegradation of azo dyes by bacteria inoculated on solid media blanca e.
The effect of media condition, ph, temperature and initial concentration of dye was studied with an. The bestperforming variants were selected for sequencing and further characterization. Characterization of an azodye degrading white rot fungus isolated from malaysia cheng wn1, sim hk1, ahmad sa1. Depending on other chemical features, these dyes fall into several categories defined by the fibres.
They can present in dyed product and in the environment due to incomplete synthesis or degradation of azo dyes. Our findings show the possibility of saving time and energy by applying a simultaneous combination of laccase and ultrasound treatments for decolorization of azo dyes. Thus degradation of azo linkage and formation of simple and less hazardous products efficient degradation of dye makes it a novel method. This clearly indicates that decolourization was due to degradation of dyes into intermediate products. Titanium dioxide in conjunction with ultraviolet light can be utilized for the decolorization and detoxification of diluted colored water waste such as alizarin, azo dyes, methyl red, methylene blue, etc. Anaerobicanoxic azo dye decolorization by several mixed and pure bacterial cultures have been reported.
Instigated by the german azo ban, measures were taken in 2002 by the european commission3 and other regulatory bodies worldwide in order to prohibit the. The photocatalytic bleaching of textile azo dye reactive blue 160 has been carried out in the presence of semiconductor photocatalyst cefeo3 and the. The reducing degradation kinetics of five azo dyes, acid orange ii, acid orange iv, acid orange gg, acid red 3b and orange i, by zerovalent iron powder in aqueous solution were studied. Microbial degradation of azo dyes 619 impact of azo dyes azo dyes and nitrated polycyclic aromatic hydrocarbons are two groups of chemicals that are abundant in the environment. Pdf azo dyes are one of the oldest industrially synthesized organic compounds characterized by presence of azo bond nn and are widely utilized as. Therefore, the purpose of this work was the study of azo dye degradation products in the presence of laccase. In this paper, using dft methods and reactivity indices, we show that the oxidative degradation of azo dyes occurs through the cleavage of the n.
The environmental, health and economic impacts of textile. The resulting library of vp variants was expressed on the surface of yeast cells and screened for azo dye degradation activity in microtiter plates mtps. Analytical biodegradation of azo dye remazol red rb by. The highest degree of azo dyes degradation was observed in isolate s17upm fig. The initial step in bacterial degradation of dye is reductive cleavage of nn azo bond leading to formation of colourless aromatic amines. Several redox mediators have been shown to be important on the anaerobic azo dye degradation rafii et al. Decolorization of dye had positive influence on the growth of. They cause severe contamination in river and ground water in the vicinity of dyeing industries4. Degradation of azo dye by bacterium, alishewanella sp. More than one million tons of dyes annually produced in the world are azo dyes cho and zoh 2007. Most of the azo dyes have sulphonate substituent groups and a high molecular weight and they are unlikely to pass through cell membranes. Degradation of azo dyes by trametes villosa laccase over. Aerobic biodegradation characteristic of different water.
The target pollutant is congo red cr, a synthetic azo dye used widely in textile dyeing process. The two major sources of release of dyes into the environment are the effluents from textile processing units and dyestuff manufacturing industries oneill et al. Toxicity assessment and microbial degradation of azo dyes. Sivakumar3 1department of microbiology manonmanium sundaranar university,tirunelvelli, 1department of microbiology and biochemistry, nadar saraswathi college of.
Substantial quantities of these dyes have been deposited in the environment, particularly in streams and rivers. It focuses on the pathways and mechanisms by which aerobic and anaerobic bacteria decolorize azo dyes and degrade the aromatic amines generated by the reaction. In many industries textile, leather, plastics, paper, food and cosmetics dyes are used as a coloring agent. In this study, the degradation of azo dyes was carried out by using bacillus species that were isolated from the soil obtained from the textile industry. This work tested the efficiency of an amalgam lamp on the degradation of an azo dye, studying the effect of dye and h 2 o 2 concentrations and ph, and the influence of some.
Additionally, the location of the reactions can be either. Characterization of an azodyedegrading white rot fungus. Pdf degradation of disperse red 167 azo dye by bipolar. Environmental engineering science 2012, 29 6, 399405. Degradation of disperse red 167 azo dye by bipolar electrocoagulation. Photocatalytic degradation of a series of direct azo dyes. Biodegradation of azo dye compounds premier publishers. In the literature, there is a large number of papers reporting on the decolorization of azo dyes. Bacillus subtilis, aeromonas hydrophila, and bacillus cereus 17, 18.
Khitounia this study was conducted on the reduction reaction of the azo dye reactive black 5 by means of the. Effective treatment systems for azo dye degradation. Degradation of azo dye by an uvh2o2 advanced oxidation. Preparation of zno photocatalyst for the efficient and. Pdf bacterial degradation of azo dye containing wastes. Reducing degradation of azo dye by zerovalent iron in. A novel method for oxidative degradation of metanil yellow. In theory, a collection of different azo dyes should be able to make a complete rainbow of colors. Photocatalytic degradation of commercial textile azo dye reactive blue 160 by heterogeneous photocatalysis kavita pamecha, vinod mehta and b.
The effects of shock dye concentration on the chemical oxygen demand and color removal efficiencies were investigated in the anaerobic baffled reactor. Bacterial degradation of textile dyes springerlink. Aerobic degradation of the azo dye acid red 151 in a. Zinc oxide zno photocatalysts were synthesized by solgel method using zinc acetate as precursor for degradation of azo dyes under uv irradiation.
Azo dyes play an important role as coloring agents in the textile, food, and pharmaceutical industry. Azo dyes azo dyes are a common classification of dyes, accounting for between 6070% of all dyes. Microbial dynamics during azo dye degradation in a uasb. Anaerobicanoxic azo dye decolorization by several mixed and pure bacterial. Bacterial decolorization and degradation of azo dyes. Photocatalytic degradation and chlorination of azo dye in saline wastewater abstract textile effluents containing high amount of azo dyes and inorganic salts are largely generated and is one of the major causes of pollution due to its discharge without adequate treatment. Azo dye, any of a large class of synthetic organic dyes that contain nitrogen as the azo group.