A review on reverse micellar approach for natural fiber dyeing

This study reviews the need and importance of non‐aqueous dyeing systems in the chemical processing industry, especially using the reverse micellar system in the dyeing of natural fibers. When it comes to conventional dyeing systems, which use large quantities of water, chemical, and energy, cause a lot of effluent load to the environment. Again the effluent water has to be treated well to eliminate all the harmful substances in it. To overcome the issues, a lot of research has been carried out in this area to minimize the use of water and chemicals in the dyeing process. Like use of low material to liquor (M:L) ratio in dyeing, dyes with high fixation at lower temperatures, low/salt less dyeing in case of reactive dyeing with cotton, cottonseed oil dyeing, microwave‐assisted dyeing, and use of supercritical carbon dioxide in case of polyester dyeing and many more. All the above said methods are aqueous‐based and, after the completion of dyeing, results in wastewater generation, which requires further treatment to reduce the harmful chemicals. Therefore, to further minimize the use of water and chemicals in the dyeing of natural fibers reverse micellar system has been introduced with the help of surfactants of both Ionic and non‐ionic in nature. As of today, a lot of work has been carried out in the dyeing of natural fibers with this system by employing Ionic, non‐ionic, and mixed surfactants. Fascinating results were obtained in the dyeing with good levelness, high exhaustion, and fixation values, and results were compared with conventional dyeing. Computer color matching studies were also done better to understand the applicability of these systems in the industry and found nearer results.