Thermoacoustic performance and CO2 capture potential in lightweight mortars with bacterial nanocellulose addition

Abstract

This study investigated the properties of lightweight mortars based on Portland cement, vermiculite, and bacterial nanofibrillated cellulose (BNFC), a sustainable biopolymer produced by bacteria. BNFC concentrations of 0.05%, 0.15%, and 0.25% were evaluated. The microstructure morphology was examined using scanning electron microscopy (SEM), while thermal analysis and CO₂ capture studies were performed using differential thermal analysis and thermogravimetry (DTA/TG). The incorporation of BNFC slightly increased consistency (from 255 to 262 mm), maintaining workability, while reducing microporosity and promoting greater formation of cement hydration products. Considering that the effect of nanocellulose is more microscopic than macroscopic, a slight reduction in mechanical strengths was observed compared to the reference mixture. The addition of BNFC increased bulk density and thermal conductivity (from 0.48 to 0.63 W/m·K), while acoustic performance showed variations, with lower transmission loss at high frequencies. BNFC (at 0.25% content) contributed to CO₂ capture by enhancing calcium carbonate formation, raising CaCO₃ content from 0.10% to 6.03%. These results indicate that BNFC is a promising additive for lightweight mortars, capable of improving cohesion, durability, and functional efficiency.