Removal of direct Yellow 27 dye using animal fat and vegetable oil-based surfactant

• Direct Yellow 27 dye was investigated as a pollutant model in aqueous solutions.
• Animal fat and vegetable oil-based surfactant was used for dye removal.
• Effect of temperature, pH, surfactant and electrolyte concentration were meaningful.
• Equilibrium time and stirring rate do not affect considerably the dye removal.
• Dye removal efficiency reached 97% using 650 ppm of surfactant at pH 11.

The textile industry uses large amounts of water in its processes. Such water ends up contaminated by a number of substances, including dyes, creating an environmental challenge. The present study aims at removing dye by applying the precipitation process using a sodium soap (anionic surfactant), derived from animal fat and vegetable oil, promoting dye decontamination using biodegradable materials. Sodium soap, in the presence of calcium ions, forms another insoluble surfactant. This new surfactant, under stirring, aggregates and forms hydrophobic flocs that are capable of adsorbing organic materials dissolved in aqueous solutions, including dyes. Dye removal was assessed considering the influence of initial surfactant concentration, temperature, pH, presence of electrolyte, equilibrium time, and stirring rate. Dye removal efficiency reached 97.6%.