Vegetable Tannins as Chrome-Free Leather Tanning

The purpose of this study is to replace chrome tannins with ecofriendly vegetable tannins as an alternative solution to prevent the public health and the environmental pollution. Vegetable tannin was extracted from Cassia singueana bark using an aqueous extraction method and applied on sheep pickle pelt. Optimum tannin extraction parameters were identified at powder concentration of 80 g/L, extraction temperature of 100°C, and extraction time of 120 mins. Chemical functionality of Cassia singueana extracted tannins was evaluated via FT-IR spectroscopy. Hence, the FT-IR spectrum confirmed the presence of wide band of phenolic hydroxyl (OH−) and carboxyl (C-O) groups connected with the aromatic ring. Moreover, physicochemical performance of the Cassia singueana extract tanned leather sample was scientifically examined and showed comparable results to conventional Mimosa tanned leather sample. The shrinkage temperature of Cassia singueana extract tanned leather recorded 83°C which is slightly higher than that of Mimosa extract (standard), 80°C. The results of mechanical properties such as tensile strength, tear strength, and elongation at break of Cassia singueana extract tanned leather sample are 15.6 N/mm2, 24.2 N/mm, and 45.3%, respectively, which are relatively higher than those of Mimosa extract tanned leather sample. A relatively higher reduction level of pollution load (BOD, COD, and TDS) was observed in the wastewater released from Cassia singueana bark extract compared to the Mimosa extract (standard). Finally, findings from this study revealed that Cassia singueana bark extract could be considered as an alternative source of vegetable tannins to reduce the consumption of chrome tanning in the leather tanning industry

Characterization and Comparative Insights on Agave Americana and Agave Sisalana Leaf Fibers for High-Performance Applications

This work is focused on characterization and comparative study of agave americana and agave sisalana leaf fibers which can be used as potential alternative for synthetic fibers in engineering applications. Physico-chemical and mechanical properties of agave fibers were determined using different analytical procedures and instruments. According to the experimental data, the mean length and diameter of agave americana fibers were maximum of 1.76 m and 411 μm, respectively. Furthermore, the particular fibers possess larger amount of hemicellulose (17.4%) and moisture (~8%) which confirmed they are relatively hydrophilic in nature. Conversely, agave sisalana fibers possess larger amount of cellulose (66.4%) and ligni10.1080/10942912.2023.2246677n (~16%) compared to agave americana fibers. Meanwhile, SEM microstructure also proved surface of agave americana fibers was comparably rough, full of cracks and linings. EDAX analysis showed presence of significant amount of C and O, including trace amount of Ca, K, Si and S. Similarly, the semicrystalline agave americana fibers are longer and thicker possessing greater mean linear density (29.68 Tex). Agave sisalana fibers recorded maximum breaking tensile strength and elongation at break (512 MPa) and (~6%), respectively. These findings strongly suggested that agave fibers possess interesting features which can be used as potential reinforcement fibers for composite engineering