Biocolorant for Leather Dyeing Applications: An Eco-benign Evaluation of Natural Coloring Agent

Exploration of biocolorant in leather industry is explored widely owing to its environmental limitation. Besides, employing synthetic dyes in leather process requires high end of pipe treatment due to their complex chemical structure. Therefore, an attempt has been made on exploiting madder root dye (Rubia cordifolia L.) for leather dyeing application. The effect of varying pretreatment regimen on madder colorant extraction, chemical characterizations (including UV-Vis, IR, particle size, zeta potential value, and thermal studies) and optimum operating leather dyeing conditions are studied. The results revealed dissolving medium pH 5, 100oC, and 60 min duration of extraction is optimum. Thus, obtained dye characteristics showed maximum absorption peak at 460 nm, with an average particle size of 166 nm. It also shows a negative zeta potential value of -5.31 which is indicative for dyeing application. The optimum leather dyeing is found at leather pH 5.5, 10% dye concentration and 4 h duration. At optimum dyeing parameters it shows good fastness, perspiration, organoleptic properties without affecting the physical characteristic. Novelty of the present research would lead to develop eco-dyeing method in leather manufacture. Moreover, the study unravels a new application of eco-benign dye to achieve sustainable process.