Аннотация:Economic feasibility and dual functionalities are contemplated as the most substantial parameters for polymers applicable in leather industries. In this work, we have identified an easy step to utilize black liquor (paper and pulp industrial waste) as a dual functional auxiliary in the post-tanning stage of leather processing. By a simple acidification method, soluble lignin (liquid lignin) was separated, and the percentage of acid input was optimized. A detailed characterization of liquid lignin products emphasized their improved functionality, better organic content, and appropriate particle size and surface potential. The presence of more hydroxyl groups with larger aromatic rings in liquid lignin results in improved leather quality with high surface smoothness and filling. In order to determine the dyeing property influenced by liquid lignin, three types of dyes were used as a dyeing agent. Along with the retanning ability, lignin was able to influence the dyeing greatly by good adsorption with minimal leaching. The liquid lignin at post-tanning process discussed herein was compared with commercial products; the leather re-tanned with liquid lignin showed greater performance with respect to environmental pollution, good dyeing characteristic, and good retanning property. Dual functionalities like retanning (fullness) along with improved dyeing characteristics divulge this liquid lignin as a twin properties polymer. Finally, liquid lignin with high organic content acts as a better twin properties polymer: detritus converted to functional auxiliary for sustainable leather processing.
