تبدیل ضایعات جامد دباغی به مواد جاذب نانو فیبری صوتی
Abstract
1- Introduction
2- Experimental
3- Results and discussions
4- Conclusion
References
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.
Introduction
Leather making process involves the conversion of animal hides/skin to a non-putrescible material called leather by subjecting them to various chemical and mechanical processes. Leather industry plays a significant role in the global economy because of the higher need for leather due to its fascinating properties over synthetic materials, which also helps in employing the weaker section of the society. However, the industry generates substantial quantities of solid and liquid wastes, which pose a serious threat to the environment. Processing of one metric ton of wet salted cow hide yields 200 kg of finished leather alongside 250 kg of tanned, 350 kg of nontanned solid wastes with the loss of 200 kg of waste in waste water and they are currently unutilized (Cabeza et al., 1998). The majority of these solid wastes are generated in pre-tanning operations like pre-fleshing, fleshing, shaving and trimming (Işler et al., 2010). Global production estimate of hides and skins comes around 6.96 million tonnes per annum. It is interesting to note that India processes 700000 tonnes contributing around 70000 tonnes to 100000 tonnes of fleshing waste (Buljan, 1999; FAO, 2016). These waste consist of water (80 %), collagen (8%), salts (8%) and fats (4%) (Nishad Fathima et al., 2014). The current disposal method for fleshing waste is landfilling, which incurs more labor cost and results in severe land pollution. Components of fleshing waste can be utilized to yield new value-added products for sustainable technologies. Valorization of waste to produce a value-added product will not only reduce the complications of waste management but will also have a positive and significant impact on the economy (Catalina et al., 2012).