Salt free goatskin preservation with sugarcane bagasse and silica gel: salinity reduction in tannery wastewater

Common salt (NaCl) is conventionally used for the preservation of animal skins. Succeeding soaking operation increases the massive chloride (Cl-) content and total dissolved solids (TDS) in emitted wastewater. Minimizing high Cl- and TDS, an approach of substituting NaCl; silica gel merged with bagasse has been taken underneath the light to preserve raw goatskin. A raw goatskin was ripped into equal two parts, half was applied with 50% NaCl and another half was applied with 10% silica gel along with 10% bagasse, and observed for up to 46 days. In this period, changes in moisture, collagen strength, bacterial growth, release of hydroxyproline, and nitrogen content were investigated following the international standard methods in a predefined interval of 0th day, 1st day, 4th day, 7th day, 11th day, 15th day, 21st day, 26th day, 31st day, 41st day and 46th day. A pilot-scale production with this material has been investigated. Reduction of Cl- and TDS was achieved by 97 and 95%, respectively compared to conventional preservation. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis of solvent-extracted material from bagasse showed the presence of antibacterial, antifungal, and antioxidant compounds, while hygroscopic nature of silica gel absorbs the inherent moisture of goatskin. Scanning Electron Microscope (SEM) micrographs showed a similar texture as conventionally preserved goatskin. Performance analysis based on ball bursting, tensile strength, and stretchiness of leathers showed equivalent results for both crust leathers. The proposed preserving materials can be used instead of NaCl to preserve goatskin for Cl- and TDS reduction in the tannery wastewater.