Electrocoagulation induced treatment of indigo carmine textile dye in an aqueous medium: the effect of process variables on efficiency evaluated using biochemical response of Gammarus pulex

A review on existing and emerging approaches for textile wastewater treatments: challenges and future perspectives

This comprehensive review explores the complex environment of textile wastewater treatment technologies, highlighting both well-established and emerging techniques. Textile wastewater poses a significant environmental challenge, containing diverse contaminants and chemicals. The review presents a detailed examination of conventional treatments such as coagulation, flocculation, and biological processes, highlighting their effectiveness and limitations. In textile industry, various textile operations such as sizing, de-sizing, dyeing, bleaching, and mercerization consume large quantities of water generating effluent high in color, chemical oxygen demand, and solids. The dyes, mordants, and variety of other chemicals used in textile processing lead to effluent variable in characteristics. Furthermore, it explores innovative and emerging techniques, including advanced oxidation processes, membrane filtration, and nanotechnology-based solutions. Future perspectives in textile wastewater treatment are discussed in-depth, emphasizing the importance of interdisciplinary research, technological advancements, and the integration of circular economy principles. Numerous dyes used in the textile industry have been shown to have mutagenic, cytotoxic, and ecotoxic potential in studies. Therefore, it is necessary to assess the methods used to remediate textile waste water. Major topics including the chemical composition of textile waste water, the chemistry of the dye molecules, the selection of a treatment technique, the benefits and drawbacks of the various treatment options, and the cost of operation are also addressed. Overall, this review offers a valuable resource for researchers and industry professionals working in the textile industry, pointing towards a more sustainable and environmentally responsible future.

Indigo Carmine: Between Necessity and Concern

Dyes, such as indigo carmine, have become indispensable to modern life, being widely used in the food, textile, pharmaceutical, medicine, and cosmetic industry. Although indigo carmine is considered toxic and has many adverse effects, it is found in many foods, and the maximum permitted level is 500 mg/kg. Indigo carmine is one of the most used dyes in the textile industry, especially for dyeing denim, and it is also used in medicine due to its impressive applicability in diagnostic methods and surgical procedures, such as in gynecological and urological surgeries and microsurgery. It is reported that indigo carmine is toxic for humans and can cause various pathologies, such as hypertension, hypotension, skin irritations, or gastrointestinal disorders. In this review, we discuss the structure and properties of indigo carmine; its use in various industries and medicine; the adverse effects of its ingestion, injection, or skin contact; the effects on environmental pollution; and its toxicity testing. For this review, 147 studies were considered relevant. Most of the cited articles were those about environmental pollution with indigo carmine (51), uses of indigo carmine in medicine (45), and indigo carmine as a food additive (17).

A critical review of textile industry wastewater: green technologies for the removal of indigo dyes

The denim textile industry represents an important productive sector. It generates wastewater with low biodegradability due to the presence of persistent pollutants, which can produce toxic and carcinogenic compounds; therefore, wastewater treatment reduces risks to aquatic life and public health. This paper presents a review of 172 papers regarding textile industry wastewater treatment for the removal of contaminants, especially indigo dyes used in the denim industry, in the context of green technologies. The physicochemical characteristics of textile wastewater, its environmental and health impacts, and the permissible limit regulations in different countries were reviewed. Biological, physicochemical and advanced oxidation processes for the removal of indigo dyes were reviewed. The goal of this study was to analyze the characteristics of green technologies; however, the research does not clearly demonstrate an effect on energy consumption savings, carbon footprint decreases, and/or waste generation. Advanced oxidation processes showed the highest color removal efficiency (95 and 97% in synthetic or real wastewater, respectively). Photocatalysis and Fenton reactions were the most efficient processes. None of the revised works presented results regarding upscaling for industrial application, and the results should be discussed in terms of the guidelines and maximum permissible limits established by international legislation. New technologies need to be developed and evaluated in a sustainable context with real wastewater.