Exploring the Sound Absorption Characteristics of Biodegradable Agricultural Wastes, Coconut Fiber, Groundnut Shell, and Sugarcane Fiber

Noise pollution is a major global health issue, especially in large cities. Its effects go beyond mere annoyance, impacting health, emotions, and behavior. As noise levels rise, researchers are looking for better solutions to address this global issue, with natural fibers emerging as a promising option for sound absorption. Traditional synthetic materials used for sound absorption have negative environmental and health impacts, leading to growing interest in biodegradable natural fibers like coconut fiber, groundnut shell, and sugarcane fiber as safer alternatives. These materials absorb sound well and are environmentally friendly and safe for human health. This study explores the use of biodegradable agricultural waste fibers (coconut fiber, groundnut shell, and sugarcane fiber) for sound absorption. Samples with densities of 75 kg/m³, 100 kg/m³, and 125 kg/m³ were mixed with an equal percentage of non-toxic PVA binder. The sound absorption coefficient was measured according to the ISO 10534-2 standard. The results showed that the 75 kg/m³ sugarcane fiber sample had the highest average sound absorption coefficient of 0.94 at 800 Hz (mid-frequency range: 500–2000 Hz). The 125 kg/m³ coconut fiber sample came next, with the highest average sound absorption coefficient of 0.91 at 1000 Hz (mid-frequency range: 500–2000 Hz). The groundnut shell material showed the lowest sound absorption coefficient, the sample with a density of 125 kg/m³ had the highest average sound absorption coefficient of 0.81 at 3150 Hz (high-frequency range). These findings suggest that these natural materials could be effective for noise reduction in places like classrooms, libraries, and cafes. The approach aligns with global sustainability efforts while addressing the issue of noise pollution in large cities.