Circular reutilization of coffee waste for sound absorbing panels: A perspective on material recycling.

The increase in coffee consumption has led to increased production of coffee waste. Methods to recycle coffee waste are constantly being researched. Coffee powder is a porous material that can effectively be used to absorb sound. In this study, sound-absorbing panels were developed using coffee waste combined with resin. A sound absorption characterization of the new material was performed. Then, the noise reduction potential using coffee-waste sound absorbers was investigated in cafés. A café has several noise sources, such as coffee machines, music, and the voices of people. The noise reduction effect was evaluated using the ODEON simulation software together with the improvement in both the clarity and reverberation time in a case study café. In the investigated room, the acoustic definition (D50) increased up to 0.8, while the reverberation time (RT) reduced to 0.6 s. The results of this study demonstrate that the noise generated in the café was reduced by recycling the coffee waste produced as a by-product in the same building. Finally, this study presents a new construction material manufactured through coffee waste that is in turn applied to cafés where the coffee waste itself is produced.