Optimization of the Sound Absorption Coefficient (SAC) from Cellulose–Silica Aerogel Using the Box–Behnken Design

[Image: see text] Noise pollution, which has become a major environmental issue in urban areas, can be minimized using acoustic insulation derived from cellulose–silica aerogel. The raw materials required in the process include waste newspaper-based cellulose, geothermal silica, and NaOH/ZnO solution. Therefore, this study investigates the effect of cellulose, silica, and ZnO concentrations on optimizing the sound absorption coefficient (SAC) using the Box–Behnken design (BBD). The results showed that the optimum conditions were obtained at 39.8578 wt % cellulose, 16.5428 wt % silica, and 0.5684 wt % ZnO. The impedance test for the cellulose aerogel and cellulose–silica aerogel showed SAC values of 0.59 and 0.70, respectively, and were characterized by XRD, FTIR, BET–BJH, SEM–EDX, and TG. The results of XRD and FTIR data indicate that the product was cellulose–silica aerogel, and the SEM micrographs showed that silica particles were attached to the fiber surface. Furthermore, type IV isotherms were observed in the cellulose–silica aerogel, typical of mesoporous materials. The presence of silica strengthened the aerogel structure, improved its thermal stability, and increased the surface area but decreased its pore size.