Production of antibacterial cement composites containing ZnO/lignin and ZnO–SiO2/lignin hybrid admixtures

Abstract

Inorganic–organic systems based on ZnO or ZnO–SiO2 and lignin were used for the first time to counteract the biodeterioration of cement composites. The stability of the oxide–lignin and interoxide–lignin combinations was confirmed by Fourier transform infrared spectroscopy, while electrokinetic studies confirmed the stability of the systems in the alkaline environment of the cement matrix. Moreover, lignin-enriched admixtures showed very good water wettability, which enabled their uniform dispersion in the cement matrix. Physical and mechanical tests confirmed the retarding effect of zinc oxide on the hydration of the cement binder in the initial setting period, which was manifested by lower mechanical parameters up to the 7th day of setting. The use of interoxide systems with silica balanced this adverse effect. The designed systems based on ZnO and lignin caused the inactivation of both bacterial and fungal pathogens, the effect being weaker in the case of the systems with silica.