Conversion of tannery solid waste to sound absorbing nanofibrous materials: A road to sustainability

Abstract

Leather making process necessitates the effective utilization of potential waste from the meat industry through tanning. This results in the generation of solid wastes leading to serious environmental concerns. Fleshing waste is considered to be one of the major solid wastes, which contains proteins and fat. The current disposal methods of fleshing wastes have various challenges and limitations. In order to overcome these drawbacks/limitations, we propose a novel approach for converting fleshing waste into a value-added material for acoustics application. Herein, protein hydrolysate was prepared from the fleshing waste through acid hydrolysis and was blended with polyvinyl (alcohol) (PVA) to produce nanofibers through the electrospinning process by optimizing the electrospinning parameters. Acid hydrolysis was done at varying conditions and its effect on the properties of the nanofibers was studied. Nanofibers were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies. The experimental observations indicated that the nanofibers produced with fleshing hydrolysate- PVA showed enhanced thermal stability than neat PVA nanofibers. The prepared nanofibrous membrane was placed on the natural sound absorbing material coir and the sound absorbing potential of this bilayer material was characterized. The sound absorption studies revealed that the bilayer material, which consisted of fleshing hydrolysate- PVA nanofibers with coir disc has better sound absorbing potential in the lower frequencies when compared to pure coir and PVA nanofibers with coir material. This gives new insights into the potential use of fleshing waste derived nanofibers as sound absorbing layer in acoustic applications.