Interaction of glyoxal with collagenous matrix and its behavioral aspects for non-toxic and sustainable tanning system

Abstract

Sustainable leather processing is viable through conventional organic tanning processing that provides scopes for quality to match with the chrome-tanned leathers. Hence, there is a need to develop sustainable tanning technology for leather processing. Glyoxal alone and in combination with wattle extract has been tried to establish a new tanning system. Glyoxal as the solo-tanning agent, optimized at the level of 5%, can produce shrinkage temperature up to a level of 72 °C, whereas the combination tanning system with the help of wattle extract yielded leather with shrinkage temperature of 92 °C. The tanned leather was further processed into crust leather, and organoleptic properties are evaluated. Thermogravimetric analyses revealed better thermal stability at 113.52 °C, with a residue of 86.94%, in comparison with the leather tanned with combination tanning system using wattle extract showing stability at 110 °C and residue of 87.29%. The visual assessment results showed that the leathers produced from experiments were soft, with smoother grain, uniform dyeing properties and overall comparable strength properties. The plausible mechanism for present tanning systems has been elucidated. The results of scanning electron microscopic analysis revealed that leather produced from glyoxal tanning was of empty type where the fibers are tightly bounded, however, having less angle of weave as compared to control sample. The reduction in Bio-chemical oxygen demand and Chemical oxygen demand values from effluent stream in the case of solo tanning showed 64–70% and 68–71%, respectively.