Natural Dyeing of Wool Using Junglans regia (Common Walnut) Leaf Extract

Abstract

The main objective of the presented research was to study the possibility of using natural colourants obtained through the aqueous extraction of fresh leaves from the Junglans regia (J. regia), or common walnut tree, for the dyeing of wool yarn. A unique principle was explored by combining the phases of extraction and mordanting into one with the aim of shortening the dyeing procedure, while at the same time extracting more colouring components. Spectrophotometric studies revealed the signifi cant impact of both mordant addition and dye-bath pH on the absorbance curve and thus on the colour and K/S values of the dyed samples. A meta-ordanting technique using ferrous sulphate produced a greater depth of shade at a wavelength of 400 nm, with respect to the concentration of mordant and the liquid ratio of the extraction. Finally, wool yarn dyed with pure leaf extracts exhibited a potent inhibiting activity against Candida albicans (C. albicans) with a moderate reduction rate of 59%, and an inhibited response against Staphylococcus aureus (S. aureus) with a low reduction rate of 38.6%.

Keywords

• natural colourants
• wool dyeing
• walnut leaf extract
• ferrous sulphate
• colourimetry
• antimicrobial activity