Water–ethanol mixtures are largely exploited for many different applications, from industrial processes to pharmaceutical formulations. Surfactants are often added to tune their interfacial properties. Sustainability concerns require redesigning such blends to minimize their environmental impact. A successful approach is to replace synthetic oil-based components with affordable unpurified bio-derived alternatives. In this respect, we have characterized aqueous mixtures of bioethanol, obtained by the fermentation of algae, and rhamnolipids, biosurfactants of microbial origin. The physico-chemical characterization of water–bioethanol binary mixtures in terms of refractive index, density, viscosity, and surface tension indicates that bioethanol behaves like pure ethanol with negligible effects of impurities. Analysis of tensiometric titrations shows that, at bioethanol contents higher than 20–30% bioethanol mass percent, rhamnolipid aggregation is impaired, whereas surface adsorption at the water–air interface remains poorly affected. Overall, bio-derived components can be proposed as a promising alternative to oil-derived chemicals in eco-sustainable formulations.
Surface and Aggregation Properties of Rhamnolipids in Water–Bioethanol Mixtures: A Step toward Green Formulation Design / Esposito, R.; Taddeo, F.; Russo, V.; Russo Krauss, I.; D'Errico, G.. - In: SURFACES. - ISSN 2571-9637. - 7:2(2024), pp. 251-264. [10.3390/surfaces7020017]
Surface and Aggregation Properties of Rhamnolipids in Water–Bioethanol Mixtures: A Step toward Green Formulation Design
Esposito R.;Taddeo F.;Russo V.;Russo Krauss I.;D'Errico G.
2024
Abstract
Water–ethanol mixtures are largely exploited for many different applications, from industrial processes to pharmaceutical formulations. Surfactants are often added to tune their interfacial properties. Sustainability concerns require redesigning such blends to minimize their environmental impact. A successful approach is to replace synthetic oil-based components with affordable unpurified bio-derived alternatives. In this respect, we have characterized aqueous mixtures of bioethanol, obtained by the fermentation of algae, and rhamnolipids, biosurfactants of microbial origin. The physico-chemical characterization of water–bioethanol binary mixtures in terms of refractive index, density, viscosity, and surface tension indicates that bioethanol behaves like pure ethanol with negligible effects of impurities. Analysis of tensiometric titrations shows that, at bioethanol contents higher than 20–30% bioethanol mass percent, rhamnolipid aggregation is impaired, whereas surface adsorption at the water–air interface remains poorly affected. Overall, bio-derived components can be proposed as a promising alternative to oil-derived chemicals in eco-sustainable formulations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.