Integrated Depilation and Fiber Opening Using Aqueous Solution of Ionic Liquid for Leather Processing

Abstract

Pollution from the leather industry is of great concern for tanners worldwide. The unhairing and fiber-opening processes, which contribute the majority of the pollution through the use of sodium sulfide and calcium hydroxide, were replaced in this study by processes using an enzyme and the imidiazolium-based ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, the deliming process, which is typically applied after liming operations, was completely avoided, eliminating the use of ammonium salts, which leads to other environmental concerns. The extent of fiber opening of the matrix was analyzed by estimating the proteoglycan content and performing histological studies. The physical strength properties of the IL-treated leathers were found to be comparable to standard norms. This study thus demonstrates that ILs can be successfully employed for unhairing, where they can enhance the activity of unhairing enzymes, as well as for the fiber-opening process of leather making.

Choline-Based Amino Acid ILs–Collagen Interaction: Enunciating Its Role in Stabilization/Destabilization Phenomena

“…Moreover, choline salts exhibited superior biocompatibility required for wound-healing applications . In addition, imidazolium ILs demonstrated unhairing cum fiber opening of the skin matrix, which has opened avenues for cleaner and greener existing processing systems. , …”

“…30 In addition, imidazolium ILs demonstrated unhairing cum fiber opening of the skin matrix, which has opened avenues for cleaner and greener existing processing systems. 31,32 The present work focuses on unraveling the underlying interactions of choline-based amino acid ILs (CAAILs) on the stability of collagen at different hierarchical orderings, that is, at the molecular and fibrillar levels. The choline cation and amino acid-based anions were selected as both are biodegradable in nature.…”

Insights into the Development of Imine-Bond-Stabilized Organic Tanning and a Heteropolymer for the Post-Tanning Process─A Metal-Free Sustainable Leather Process

“…Leather trials were performed to evaluate the tanning efficiency of modified vanillin. The percentage of modified vanillin offered is based on the collagen crosslinking studies; 10% of vanillin was used for the leather trials, the partially pickled pelt was maintained at pH 5, the drumming was performed for 2 h, and then 1% formic acid was used as a fixing agent. , The hydrothermal stability of the tanned leather is 70 °C (Figure c). After the tanning process, the leather is subjected to a post-tanning operation to impart functional properties to the tanned leather.…”

A clean and efficient processing system to improve the fluffiness of down fibers based on multi-enzymes

“…The main function of papain is to hydrolyze the peptide bonds in the down fibers and expose the active groups to make the down fibers reach a loose state. 19 The down fiber will increase its contact with TGase after exhibiting this loose state, thereby improving the intermolecular cross-linking efficiency of the down fiber, which also improves the fluffiness of the down fiber. Because the effect of papain and TGase on down fiber can be regarded as the combined effect of first hydrolysis and then cross-linking, the binding force between down fiber molecules can be better improved.…”