[Excerpt] Resins have been used for years for the purification and characterization of ionic substances. The use of these resins allows not only remove impurities or increase the concentration of metabolites from industrial streams, but also allows define their ionic structure. In general, surfactants can be classified as non-ionic, anionic, cationic or amphoteric, what is going to define their future application at industrial scale. For example, anionic surfactants present the greatest wetting and emulsifying properties, while cationic ones have excellent antibacterial properties as well as good emulsifier capacities. Otherwise, amphoteric surfactants, which may have anionic or cationic properties depending on pH, are widely used in personal care products because of their less irritability to skin and eyes in comparison with other types of surfactants. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904)University of Vigo (Spain
