A Novel Preservation-cum-Unhairing Process for Sustainable Leather Manufacturing: An Unconventional Approach in Leather Making

Content: Preservation (or) curing is an important unit process for transportation and storage of raw hides/skins without any deterioration. Popular preservation process is mostly achieved by reducing the moisture content of hides/skins using common salt (NaCl). Usage of salt in preservation process leads to generation of large amount of contaminated salt, total dissolved solids (TDS) and consume huge amount of water for subsequent rehydration step. On the other hand, lime-sodium sulphide based reductive process is commonly employed for the removal of hair from hides/skins. This process leads to generation of lime sludge and possible evolution of toxic hydrogen sulphide gas thereby making the working atmosphere more unpleasant. Several alternative techniques for preservation as well as unhairing process have been developed individually to replace salt and sulfide, respectively. However, a single compound performing dual functions such as preservation and unhairing action in neutral pH conditions has not explored so far. In the present work, a novel formulation has been developed, which possess the both preservation and unhairing potential, and applied on the hides/skins for storage up to 6 months at ambient conditions without dehydration. Low level of sulphide was used during alkaline fiber opening for complete removal of hair. The strength and organoleptic properties are on par with salted skins/hides. The developed process completely eliminates the use of salt and 75% sulphide and also reduces the time and water required for soaking process. The developed system reduces 85% of pollution load discharged from soaking and unhairing processes. Take-Away: One pot system for salt free preservation and low sulfide dehairing for sustainable leather manufacture

Collagen based magnetic nanocomposites for oil removal applications

A stable magnetic nanocomposite of collagen and superparamagnetic iron oxide nanoparticles (SPIONs) is prepared by a simple process utilizing protein wastes from leather industry. Molecular interaction between helical collagen fibers and spherical SPIONs is proven through calorimetric, microscopic and spectroscopic techniques. This nanocomposite exhibited selective oil absorption and magnetic tracking ability, allowing it to be used in oil removal applications. The environmental sustainability of the oil adsorbed nanobiocomposite is also demonstrated here through its conversion into a bi-functional graphitic nanocarbon material via heat treatment. The approach highlights new avenues for converting bio-wastes into useful nanomaterials in scalable and inexpensive ways

Conducting Leathers for Smart Product Applications

Leather is a unique consumer material possessing a variety of properties such as strength, viscoelasticity, flexibility, and longevity. However, the use of leather for smart product applications is a challenge since it is an electrically insulating material. Here, we report a simple method to produce conducting leathers using an in situ polymerization of pyrrole. The concentrations of pyrrole, ferric chloride, and anthraquinone sulfonic acid and the number of polymerization were optimized to produce maximum conductivity in the treated leathers. The coating of polypyrrole in the treated leathers was probed using Fourier transform infrared spectroscopy, X-ray diffraction, and electron microscopic analysis. We also show that the treated leathers are black through reflectance measurements, thereby suggesting that the use of toxic and expensive dyes can be avoided for coloration process. We further demonstrate that the treated leathers, with a maximum conductivity of 7.4 S/cm, can be used for making conductive gloves for operating touch-screen devices apart from other smart product applications