Sustainable leather tanning with Pontederia crassipes tannin: A promising eco-friendly alternative

Abstract

Considering the considerable environmental impact resulting from basic chromium sulfate, the exploration of vegetable tanning materials as an eco-friendly alternative has gained substantial interest. This study endeavors to extract tannins from Pontederia crassipes using various solvents (water, acetone, methanol, and ethanol) and evaluate their potential as a vegetable tanning agent for leather processing. Among the solvents, methanol exhibited the highest extraction efficiency at 26.34%. UV–Vis spectroscopy, FT-IR spectroscopy, and titrimetric analysis confirmed the presence of total tannins at 152.25 mg/g, which encompassed polyphenolic compounds such as epicatechin, catechin hydrate, and catechol. The antimicrobial behavior of the extracted tannin was confirmed by antimicrobial analysis. Notably, leather tanned with Pontederia crassipes tannin displayed an impressive shrinkage temperature of 83.31 °C, tensile strength 286.33 kg/cm², and elongation 63.33%. This innovative tanning approach also yielded enhanced properties such as tensile strength, Bauman tear strength, stitch tear strength, tongue tear strength, and percentage of elongation, surpassing those of traditional vegetable-tanned leather. A closer look at the surface of the tanned leathers using Scanning electron microscopy (SEM) revealed compact fiber structures and uniform surface. Moreover, the Fourier-transform infrared spectroscopy (FTIR) analysis revealed clear functional groups within the Pontederia crassipes tanned leather, as evidenced by the broad peak observed. These results collectively imply that Pontederia crassipes tannin presents promise as an eco-friendly substitute for basic chromium sulfate and a novel reservoir of vegetable tannins for the leather sector.