Toxicity and color reduction of reactive dyestuff RB21 and surfactant submitted to electron beam irradiation

Camila Gomes Melo,Sueli Ivone Borrely,Jorge Marcos Rosa,Vanessa Silva Granadeiro Garcia,Maria Conceição Costa Pereira

doi:10.15392/bjrs.v9i1a.1311

Abstract

There is an unwelcome reaction between the coloring and the water during the dyeing procedure, a portion of the coloring agent is lost in the bathing and it will compose the final whole effluent. The high absorbance index is related to lost dyes and they also contribute with the toxic effects to the aquatic biota. In addition, these effluents contain large quantity of surfactants applied during dyeing baths, which also contribute to the high toxicity in these samples. The objective of this study was to evaluate electron beam irradiation technology, applied in samples of the Color Index Reactive Blue 21 (RB21) dye and in samples of surfactant nonionic and in order to reduce toxicity for both and for RB21, color reduction. Among the objectives of the study there are the dye exhaustion degree, and some physic-chemical parameters. The acute toxicity assays were carried with Daphnia similis microcrustacean and the results for of dyestuff solution were: the irradiated samples with concentration of 0.61g.L-1 did not present significant results, the EC 50(%) value was to 58.26 for irradiated sample with 2.5kGy and EC 50(%) 63.59 for sample irradiated with 5kGy. The surfactant was more toxic than RB 21, with EC 50(%) value at 0.42. The color reduction reached 63.30% for the sample of the lowest concentration of effluent. There was a reduction of pH during irradiation.

Highlights

The water is a vital resource for the human consumption, for keeping health biota, and agricultural and industrial suitable production
Preparation of the samples The reactive dyestuff and surfactant aqueous solution were prepared at LEBA (Environmental and Biological Assays Laboratory) as described below. - Dyestuff Reactive Blue 21 (RB 21): the concentration 0.61 g L-1 was used on the basis of the study developed by Rosa et al [13], assessing the exhaustion degree to RB 21 dyestuff, with standard concentration of 1.5 g L-1 in the manufacturer dyestuff
Similar data was obtained to all samples of reactive RB 21 dyestuff before and after irradiation with 2.5 kGy and 5 kGy

Summary

Introduction

The water is a vital resource for the human consumption, for keeping health biota (fauna and flora), and agricultural and industrial suitable production. There is a huge need for rational use of water, avoiding the wastes and the pollution, which is related environmentalists, and governmental institutions and its productive processes. The primary and secondary parts of textile processing require more water due to dyeing of a given substrate [2]. The cotton fiber stands out as the most consumed by the clothing sector, and more than half of its production is dyed with reactive coloring agents. The molecules of such dyeing are reacting to the fibers in alkaline pH, through Hydrogen Bonds, Van der Waals Force and, through Covalent Bonds [3]. As well as the reaction between dyestuff and fiber, it generates the reaction between dyestuff and the water used in the bathing, known as hydrolyzed dyestuff

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Conclusion