Dyes, Environmental Chemistry

Abstract

Synthetic organic dyes are essential to satisfy the ever growing demands in terms of quality, variety, fastness, and other technical requirements for coloration of a growing number of substances. Beginning in 1970, however, the dyestuff and textile industries have become increasingly subject to international, federal, and state regulations designed to improve health, safety, and environment. Therefore, in an attempt to provide a perspective of the environmental problems posed by synthetic organic colorants, and the efforts being made by industry, academia, and government to solve these problems, this article includes the physical, chemical, and biological methods of effluent treatment of dye wastewater. Specifically, the physical methods are adsorption, sedimentation, flotation, flocculation, coagulation, foam fractionation, polymer flocculation, reverse osmosis and ultrafiltration, ionization radiation, and incineration; the chemical methods are neutralization, reduction, oxidation, electrolysis, ion exchange, and wet air oxidation; the biological methods are stabilization ponds, aerated lagoons, trickling filters, activated sludge, anaerobic digestion, and bioaugmentation. Also included are fate of dyes, analytical methods, pollution prevention, heavy metals, toxicity, and legislation.

Adsorption of Methylene Blue Dye onto Bush Cane Bark Powder

“…The discharge of these dyes in effluents emanating from such industries is a major cause of serious environmental pollution [1,2], since, when discharged, the dyes can seriously hinder the penetration of light and disturb the biological processes occurring in many water bodies. More so, the natural degradation of these dye compounds, when released into the environment, usually yields highly toxic and carcinogenic products [3][4][5]. Compared with well-known techniques like filtration, precipitation, coagulation and ozone treatment for the removal of dyes from effluents, the adsorption technique provides greater merits of simplicity and very low cost involvement.…”

Kinetics of the oxidative degradation of thionine dye by hydrogen peroxide catalyzed by supported transition metal ions complexes

“…In the last few decades, the dyestuff and allied industries have become subject to increasingly stringent regulations designed to protect human health and the environment. As a consequence, the effective elimination of colored effluents originating from the textile and related industries has become an important problem due to their refractory nature 1–3. The most common methods employed to treat wastewater containing organic dyes and pigments are classified into three main categories: (i) physical (adsorption, filtration, and flotation),4–7 (ii) chemical (oxidation, reduction, and electrochemical),8–17 and (iii) biological (aerobic and anaerobic degradation) 18–20.…”

Advanced oxidation of raw and biotreated textile industry wastewater with O3, H2O2 /UV-C and their sequential application

“…Since textile effluents contain highly structured polyaromatic dyestuff molecules and may even be toxic to microorganisms, biological treatment of them is quite inefficient 2. Moreover, conventional physicochemical treatment methods such as coagulation or activated carbon adsorption are also insufficient for decolorization due to the low molecular weight and high water solubility of certain dyestuffs (eg reactive, direct and sulfur dyestuffs) applied during the cotton dyeing process 3. 4 From the ecological point of view, the above listed treatment techniques result in a phase transfer of pollutants and thus destructive treatment methods for the remediation of recalcitrant, toxic and/or hazardous pollutants are currently under investigation.…”