Valorization of lignin for the development of sustainable amphiphilic modifiers with high surface activity for environmentally responsible cement systems

Developing construction materials with a reduced environmental footprint requires the use of biosurfactants or bioinspired modifiers that can partially replace conventional petrochemical additives. This study focuses on the surface activity of bioinspired amphiphilic compounds with aromatic structures, obtained from renewable resources. The aim was to evaluate their adsorption capacity and potential application in cement technology, particularly in influencing rheology and the porous structure of cement mixtures.
Aqueous solutions of bioinspired compounds with different molecular weights and chemical modifications were prepared. For comparison, synthetic additives were analyzed, including sulfonated melamine–formaldehyde condensate (SMF), sulfonated naphthalene–formaldehyde condensate (SNF), and hydroxycarboxyl starch derivatives.
Surface tension was measured using the Du Noüy ring method with a KSV Sigma 701 tensiometer. Adsorption parameters—surface excess (Γ), molecular area (A_min), and Gibbs free energy (ΔG_ads)—were calculated using the Szyszkowski equation.
The bioinspired compounds demonstrated high surface activity and formed stable, compact monolayers. Medium molecular weight samples showed the most effective packing, indicating favorable dispersing properties in cement systems. In comparison to synthetic superplasticizers and starch derivatives, these compounds exhibited competitive adsorption and surface activity, highlighting their practical potential.
The findings confirm that renewable, aromatic amphiphilic compounds can serve as a foundation for designing next-generation biosurfactants. Their use in cement formulations supports sustainable construction practices and circular economy principles, reducing reliance on non-renewable resources and industrial waste while improving material performance.