Treatment of textile model effluents containing indigo dye through the ultrafiltration process using polymer-based membranes

The purpose of this study is to characterized and treated textile model effluents similar to those generated by textile finishing industries. These effluents, referred to as ETMBI, are prepared using indigo blue, a dye from the vat dye family. The physicochemical characterization of these effluents yielded the following results: pH= 11.80; conductivity = 1.7 µS/cm; total suspended solids (TSS) = 354 mg/l; turbidity = 868 NTU; chemical oxygen demand (COD) = 910 mg (O₂)/l; total organic carbon (TOC) = 934 mg (O₂)/l; and optical density (OD) = 0.256 at a maximum wavelength (λ_max)= 665 nm. These results exceed the standards for the textile finishing effluents, which is why these effluents require treatment using ultrafiltration processes with 14%-PSU-M and 11-3%-PSU-PSE-M polymer membranes, which have already been synthesized and characterized at our laboratory scale, as reported in our previous study. Furthermore, the treatment of these effluents with the aforementioned membranes resulted in significant reductions in all the studied physicochemical parameters. The obtained results for the abatement rate of parameters such as conductivity, TSS, turbidity, COD, TOC, and discoloration rate were recorded as 40%; 65.54%; 48.73%; 52.97%; 55.57%; and 80.08%, respectively, when using 14%-PSU-M type membranes. When using 11-3%-PSU-PSE-M membranes, the values reached 47.06%; 70.62%; 53.34%; 54.72%; 57.82%; and 87.10%, respectively. The comparative study of the treatment performance of these effluents using the different membranes showed that the 11-3%-PSU-PSE-M membranes performed better than the 14%-PSU-M membranes.