Separation of reactive dyes using natural surfactant and micellar-enhanced ultrafiltration membrane

This study presented the membrane separation integrated with surfactant micellisation for the removal of dye molecules from aqueous media, commonly identified as micellar enhances ultrafiltration (MEUF). Three different naphthols or naphthalene dye (AS-LB, AS-OL, and AS-BR), three kinds of remazol dye (Red Rb, Yellow G, and Turquoise Blue) and a pure grade saponin were used in this study. This study investigated the MEUF performance to remove the reactive dye and to determine the effect of surfactant addition in the feed solution by determining the micelle loading profile. A significant decline of the initial normalized flux compared to the final flux was shown in all of the filtration processes for the removal of remazol dye. However, the flux profile of the naphthol feed showed a more stable trend. The addition of saponin as a surfactant in the feed solution improved the rejection of the dye pollutant, and this was because of the successful entrapment of the dye pollutant in the surfactant micelle structure. The highest rejections for remazol Red Rb, yellow G, and Turquoise Blue were 97.32%, 98.88%, and 98.88%, respectively. In addition, the highest rejection for naphthol AS-BR, AS-LB, and AS-OL were 99.08%, 94.16%, and 93.59%, respectively. Adding the surfactant decreased the value of micelle loading (amount of dye solubilized in surfactant micelle). It was confirmed that the MEUF successfully removed the dye pollutant from the wastewater and increased the rejection of the surfactant itself.