Problem Statement
Industries are generated waste water, which contain dyes and pigments in waste water. Characteristically high in colour and organic content (Grag, et al., 2004). Dyes are widely used in industries such as textile, rubber, paper, plastic, and cosmetic. There are many of dyes exist in industries and one of them is methyl red and through nano zerovalent iron removal of dyes from waste water. Dye industry effluents constitute one of the most problematic wastewaters to be treated not only for their high chemical and biological oxygen demands (BOD) and suspended solid and content in the toxic compounds but also for their aesthetic impact. Methyl red, if accumulates into the body by inhalation, ingestion, or by absorption through skin, may affect the central nervous system, cause liver and kidney damage. It is regarded as a poisonous substance, which may also cause blindness if swallowed. Its vapours are harmful to the eyes, can cause irritation and painful sensitivity to light. Ingestion is also likely to cause digestive tract irritation, respiratory failure, cardiovascular collapse, and kidney failure and severe depression. Chronic exposure to small amounts can cause dermatitis. Prolonged or repeated contact with methyl red may cause dryness, cracks and irritation on the skin. …show more content…
In animals, methyl red has adverse reproductive and foetal effects. The azo dyes are the largest and most versatile of all dyes used in the textile and dyeing industries and they are characterized by the presence of one or more azo group [-N=N-] in association with one or more aromatic rings (Gordon and Gregory, 1983). The azo dyes are toxic and carcinogenic. Methyl red is also a synthetic azo dye. It is therefore essential that any effluent containing an azo dye like methyl red must not be discharged into natural water bodies without prior treatment. Azo dyes are widely used in industry. A large amount of these dyes is discharged into streams and rivers, and they are considered as an environmental pollutant. Some of these compounds may accumulate in food chains and eventually reach the human body through ingestion. Intestinal microbiota and to a lesser extent, the liver enzymes, are responsible for the cleavage of azo dyes into aromatic amines. Some of human endogenous bacteria that contaminate bladder can metabolically activate aromatic amines that are produced from azo dyes (procarcinogens). The addition of the nitro-group to these aromatic amines would convert them into direct mutagens. Many azo dyes (aromatic amines) have been found to be carcinogenic in laboratory animals, affecting the liver, urinary bladder and intestines. Specific toxic effects in humans have not been established, but some dyes are known to be mutagenic. Benzidine and its metabolic derivatives have been detected in the urine of workers exposed to Direct azo dyes. An epidemiological study of silk dyers and painters with multiple exposures to benzidine based and other dyes indicates a strong association with bladder cancer. 1.4 Adsorbate: Methyl red is a synthetic dye of chemical formula, [(CH3)2NC6H4N=NC6H4CO2H], and chemical name 2- [4-(dimethylamino) phenyl azo] benzoic acid (Fig 1). It is soluble in water and the aqueous solution has a bright red colour. Methyl red with molecular formula, C15H15N3O2, has a melting point of 452 - 455 K and absorption maximum of 523 - 526 nm at pH 4.5 and 410 - 434 nm at pH 6.2. It is a week acid with the pKa value of 5.05± 0.05 at 298 - 303 K [Kolthoff 1953]. Fig. 1.Chemical structure of Methyl Red 1.5 Adsorbent: Bare INPs is composed of a core which consists primarily of zero-valent or metallic iron while the mixed valent [i.e., Fe (II) and Fe (III)] oxide shell is formed as a result of oxidation of the metallic iron (Fig 2). Iron typically exists in the environment as iron (II)-and iron (III)-oxides, and as such, INPs is a manufactured material. Thus, far, applications of INPs have focused primarily on the electron-donating properties of INPs. Under ambient conditions, INPs is fairly reactive in water and can serve as an excellent electron donor, which makes it a versatile remediation material (Stumm, and Morgan, 1996). Fig. 2.The Core-Shell Model of Zero-Valent Iron Nanoparticles Chapter-2 LITERATURE REVIEW 2. Literature Review Waste water from Textile and
Industries are generated waste water, which contain dyes and pigments in waste water. Characteristically high in colour and organic content (Grag, et al., 2004). Dyes are widely used in industries such as textile, rubber, paper, plastic, and cosmetic. There are many of dyes exist in industries and one of them is methyl red and through nano zerovalent iron removal of dyes from waste water. Dye industry effluents constitute one of the most problematic wastewaters to be treated not only for their high chemical and biological oxygen demands (BOD) and suspended solid and content in the toxic compounds but also for their aesthetic impact. Methyl red, if accumulates into the body by inhalation, ingestion, or by absorption through skin, may affect the central nervous system, cause liver and kidney damage. It is regarded as a poisonous substance, which may also cause blindness if swallowed. Its vapours are harmful to the eyes, can cause irritation and painful sensitivity to light. Ingestion is also likely to cause digestive tract irritation, respiratory failure, cardiovascular collapse, and kidney failure and severe depression. Chronic exposure to small amounts can cause dermatitis. Prolonged or repeated contact with methyl red may cause dryness, cracks and irritation on the skin. …show more content…
In animals, methyl red has adverse reproductive and foetal effects. The azo dyes are the largest and most versatile of all dyes used in the textile and dyeing industries and they are characterized by the presence of one or more azo group [-N=N-] in association with one or more aromatic rings (Gordon and Gregory, 1983). The azo dyes are toxic and carcinogenic. Methyl red is also a synthetic azo dye. It is therefore essential that any effluent containing an azo dye like methyl red must not be discharged into natural water bodies without prior treatment. Azo dyes are widely used in industry. A large amount of these dyes is discharged into streams and rivers, and they are considered as an environmental pollutant. Some of these compounds may accumulate in food chains and eventually reach the human body through ingestion. Intestinal microbiota and to a lesser extent, the liver enzymes, are responsible for the cleavage of azo dyes into aromatic amines. Some of human endogenous bacteria that contaminate bladder can metabolically activate aromatic amines that are produced from azo dyes (procarcinogens). The addition of the nitro-group to these aromatic amines would convert them into direct mutagens. Many azo dyes (aromatic amines) have been found to be carcinogenic in laboratory animals, affecting the liver, urinary bladder and intestines. Specific toxic effects in humans have not been established, but some dyes are known to be mutagenic. Benzidine and its metabolic derivatives have been detected in the urine of workers exposed to Direct azo dyes. An epidemiological study of silk dyers and painters with multiple exposures to benzidine based and other dyes indicates a strong association with bladder cancer. 1.4 Adsorbate: Methyl red is a synthetic dye of chemical formula, [(CH3)2NC6H4N=NC6H4CO2H], and chemical name 2- [4-(dimethylamino) phenyl azo] benzoic acid (Fig 1). It is soluble in water and the aqueous solution has a bright red colour. Methyl red with molecular formula, C15H15N3O2, has a melting point of 452 - 455 K and absorption maximum of 523 - 526 nm at pH 4.5 and 410 - 434 nm at pH 6.2. It is a week acid with the pKa value of 5.05± 0.05 at 298 - 303 K [Kolthoff 1953]. Fig. 1.Chemical structure of Methyl Red 1.5 Adsorbent: Bare INPs is composed of a core which consists primarily of zero-valent or metallic iron while the mixed valent [i.e., Fe (II) and Fe (III)] oxide shell is formed as a result of oxidation of the metallic iron (Fig 2). Iron typically exists in the environment as iron (II)-and iron (III)-oxides, and as such, INPs is a manufactured material. Thus, far, applications of INPs have focused primarily on the electron-donating properties of INPs. Under ambient conditions, INPs is fairly reactive in water and can serve as an excellent electron donor, which makes it a versatile remediation material (Stumm, and Morgan, 1996). Fig. 2.The Core-Shell Model of Zero-Valent Iron Nanoparticles Chapter-2 LITERATURE REVIEW 2. Literature Review Waste water from Textile and