Removal of Reactive Blue 19 using nonionic surfactant in cloud point extraction

Abstract

Textile wastewater represents a serious environmental issue due to the presence of toxic dyes. The cloudpoint extraction, which involves the application of nonionic surfactants at temperatures above the cloudpoint, was applied in this research to remove Reactive Blue 19 dye from a synthetic wastewater. Nonyl-phenol with 9.5 ethoxylation degree was used as nonionic surfactant. Dye removal was evaluated consid-ering the influence of surfactant concentration, temperature, and initial dye concentration. Equilibriumdata followed the Langmuir isotherm model. Negative Gibbs energy, enthalpy, and entropy showed thatthe process was spontaneous and exothermal. Dye removal reached 91% when using 7.5 wt% surfactant,at 65.0°C. Cloud point extraction can be used as an efficient alternative for treating textile wastewatercontaining Reactive Blue 19