Cleaner Leather Tanning and Post-Tanning Processes Using Oxidized Alginate as Biodegradable Tanning Agent and...

Traditional leather tanning processes often rely on chromium, aldehydes, and phenols, which pose environmental and health risks. While these chemicals improve leather durability and appearance, they are not biodegradable and can contaminate water and soil. Prior research has shown that alternatives such as plant-based tannins and synthetic polymers can reduce environmental impact. However, no prior work had resolved how to combine biodegradable tanning agents with flame-retardant properties in a single process. This gap motivated the exploration of oxidized alginate as a tanning agent and nano-hydroxyapatite as a flame retardant. The need for cleaner leather production has driven interest in eco-friendly materials that maintain industrial performance. No prior work had tested the combined use of oxidized alginate and nano-hydroxyapatite in leather tanning. That uncertainty drove the development of a chrome-, aldehyde-, and phenol-free tanning process. This approach aims to address both environmental concerns and functional requirements in leather manufacturing.

This study aimed to develop a cleaner leather tanning process using oxidized sodium alginate (OSA) as a biodegradable tanning agent and nano-hydroxyapatite (nano-HAp) as a flame retardant. The researchers sought to replace conventional toxic chemicals with sustainable alternatives. They focused on creating a tanning method that is free from chromium, aldehydes, and phenols. The goal was to evaluate the feasibility of using OSA and nano-HAp together in a single process. The study also aimed to assess the mechanical and fire-resistant properties of the resulting leather. The motivation stemmed from the need to reduce environmental contamination and improve leather sustainability. The authors tested whether OSA could effectively stabilize collagen and whether nano-HAp could provide flame resistance. This work addresses the gap in eco-design leather production without compromising industrial standards.

The researchers first oxidized sodium alginate (SA) using potassium periodate to produce oxidized sodium alginate (OSA). They then combined OSA with a low concentration of nano-hydroxyapatite (nano-HAp) to create a tanning solution. The leather matrix was formed using collagen, OSA, and nano-HAp. To analyze the interactions, they used micro-differential scanning calorimetry (micro-DSC) to assess collagen stabilization by OSA. They also employed ¹H unilateral nuclear magnetic resonance (NMR) to study the aqueous environment around collagen molecules. Attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) were used to examine the matrix structure. Industrial standard tests were conducted to evaluate mechanical strength and fire resistance. The study combined analytical and industrial testing methods to validate the prototype leather’s properties.

The findings showed that OSA effectively interacts with collagen and stabilizes the collagen-OSA matrix. Micro-DSC results indicated that OSA enhances thermal stability in leather. ¹H NMR analysis revealed that OSA and nano-HAp limit water mobility around collagen molecules. FTIR-ATR and SEM-EDS confirmed the successful integration of OSA and nano-HAp into the leather matrix. The mechanical properties of the new leather prototype met industrial standards. Fire resistance tests demonstrated that nano-HAp provided flame-retardant properties without toxic additives. The leather prototype was found to be chrome-, aldehyde-, and phenol-free. These results suggest that OSA and nano-HAp are viable alternatives for cleaner tanning technologies.

The authors concluded that oxidized sodium alginate (OSA) and nano-hydroxyapatite (nano-HAp) can replace conventional tanning chemicals in leather production. Their findings suggest that OSA stabilizes collagen and improves leather durability. The study also proposes that nano-HAp contributes to flame resistance without toxic additives. The leather prototype met industrial mechanical standards and showed no contamination from chromium or phenols. These results may support the development of eco-friendly leather manufacturing processes. The authors propose that this approach aligns with sustainable design principles. They suggest that the combination of OSA and nano-HAp offers a cleaner alternative to traditional tanning agents. This work may guide future efforts to reduce the environmental impact of leather production.