Abstract

Conventional cotton bleaching relies on hydrogen peroxide under high temperatures and alkaline conditions, leading to high water and energy consumption. This study evaluates ozone as a sustainable alternative oxidizing agent to improve process efficiency. An ozone-based process was investigated by analyzing the influence of pH, fabric moisture content, and chemical additives, including stabilizers and surfactants. Performance was assessed using CIELab coordinates together with evaluation of substrate integrity through degree of polymerization to ensure suitability for subsequent dyeing. Results indicate that bath composition is critical, with both acidic and alkaline media outperforming neutral conditions. Fabric moisture was identified as a key parameter, where periodic renewal of the impregnation bath significantly enhanced bleaching efficiency. Under optimal conditions, the process achieved notable bleaching levels within short treatment times and with low energy requirements. These findings demonstrate that ozone bleaching represents a promising, energy-efficient alternative for cotton pre-treatment, capable of providing substrates suitable for high-quality and sustainable textile colouration.

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