Allium Cepa Peel Waste A Sustainable Solution for Antibacterial Leather Dyeing with GS Powder Mordanting

Abstract

Using natural dyes rather than synthetic dyes is an option that can be pursued to achieve sustainability in leather dyeing. The main disadvantage of natural dyeing is poor wet and dry rub fastness and the requirements of metal mordants for fixing. In this work, onion peel waste is the chosen raw material to produce natural dye for leather dyeing without metal mordant. Adding commercial syntans and vegetable tannins with the onion peel dye in the post tanning process produces good quality dyed leather without using any mordants. The optimal particle size of eco-friendly onion peel dye was extracted from onion peel (Allium cepa) using a modified  aqueous extraction method. The extracted dye was examined by  various instrumental techniques to characterize the functional  groups by Fourier transform infrared spectroscopy (FT-IR),  optical properties by UV-VIS spectrophotometry, size by Malvern  Instruments, and thermal stability by Thermogravimetric Analysis  (TGA). The results express the suitability for application in the  leather dyeing process. The extracted dye was analysed for the  antibacterial activity towards Bacillus subtilis and Escherichia coli, and the results revealed that the natural dye has an antibacterial  effect Crust leather dyed only with extracted dye showed poor dye