Cleaner Leather Tanning and Post-Tanning Processes Using Oxidized Alginate as Biodegradable Tanning Agent and Nano-Hydroxyapatite as Potential Flame Retardant

In this study, sodium alginate (SA) was oxidized with potassium periodate to produce analginate-based tanning agent. Using OSA as a biodegradable tanning agent and a nano-hydroxyapatite(nano-HAp) low concentration suspension to give flame retardancy to leather, eco-design con?cepts were applied to establish a chrome-, aldehyde-, and phenol-free tanning process. Micro-DSC,1H unilateral nuclear magnetic resonance (NMR), attenuated total reflection mode Fourier transforminfrared spectroscopy (FTIR-ATR), and scanning electron microscopy with energy dispersive X-rayspectroscopy (SEM-EDS) were used to investigate the complex matrix collagen-OSA-nano-HAp.Micro-differential scanning calorimetry (micro-DSC) was used to assess OSA's ability to interact withcollagen and stabilize the collagen-OSA matrix, while 1H unilateral (NMR) was used to investigatethe aqueous environment and its limitations around collagen molecules caused by their associationwith OSA and nano-HAp. Industrial standard tests were used to assess the mechanical properties andfire resistance of the new leather prototype. The findings reported here indicate that both OSA andnano-HAp are suitable alternatives for cleaner tanning technologies and more sustainable leather.