Comparison of the colour fading effects of sodium hypochlorite and ozone treatments

Abstract

Colour fading is a method that is used to achieve a vintage look in textile goods. It is desired by customers in the textile market. Additionally, customers demand that these types of products are produced by environmentally friendly methods. In this study, sodium hypochlorite and ozone were used as laboratory-scale colour fading reagents on dyed cotton fabrics. Cotton fabrics were dyed with four different primary colours: red, yellow, blue and black. Dyed fabrics were subjected to ozone and sodium hypochlorite treatment under different treatment conditions. Ozone was chosen as an alternative for comparison and it was applied at fixed flow rate (5 L/min) and time (10 minutes). Colour differences, chemical oxygen demand, bursting strength and energy, water and chemical consumptions were measured. The surface morphology was characterised by scanning electron microscopy. We can conclude that ozonation is effective in discharging colour from dyed fabric samples, and the colour-fading effect is uniform, like in sodium hypochlorite treatment. It was observed that both processes are similar in terms of strength and surface modification. Results showed a 90% cost reduction, 85% water conservation and a 26% chemical oxygen demand reduction.