Reactive Dyeing of Cotton Yarns by Exhaustion Method in an Oil-Based Medium Using Crude and Refined Soybean Oil

Dyeing is a major contributor to pollution, with high concentrations of hydrolyzed dyes and electrolytes in its effluents. Recent studies suggest the possibility of dyeing cotton substrates with reactive dyes in an oil medium, reducing the need for electrolytes. This study evaluated the dyeing of co...

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Bibliographic Details
Main Authors: Edilson Locks, Selene Maria de Arruda Guelli Ulson de Souza, Afonso Henrique da Silva Júnior, Carlos Rafael Silva de Oliveira, Catia Rosana Lange de Aguiar
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Colorants
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Online Access:https://www.mdpi.com/2079-6447/4/2/11
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Summary:Dyeing is a major contributor to pollution, with high concentrations of hydrolyzed dyes and electrolytes in its effluents. Recent studies suggest the possibility of dyeing cotton substrates with reactive dyes in an oil medium, reducing the need for electrolytes. This study evaluated the dyeing of cotton yarns with reactive Red 195 dye in an oil medium using crude and refined soybean oil. The method employed 75% oil and 25% water, with the oil recovered for reuse, significantly reducing water consumption and effluent generation. Dyeing with crude soybean oil showed higher color intensity than the conventional method and the use of refined soybean oil. Additionally, reducing electrolyte concentration from 75 to 18.75 g/L did not affect color intensity, yielding similar results to conventional aqueous dyeing. The dyed substrates were tested for washing, rubbing, and lightfastness, showing comparable performance to conventional methods. The dyeing followed pseudo-second-order kinetics, and the Freundlich isotherm model better fit the oil medium process. FTIR analysis revealed no changes in the functional groups on the yarn surface, and tensile strength tests showed similar results across methods. These findings indicate that oil medium dyeing can reduce electrolyte use, conserve water, and allow for oil reuse, demonstrating potential for industrial-scale application.
ISSN:2079-6447