Indigo Dye Removal From Cotton Denim Waste

Denim is a kind of cotton warp-faced twill that is characterised by indigo dying and only the warp is dyed. The aim of this project is to develop a physical method for removing those indigo dye colour, so that the denim waste can be more easily reused or re-dyed.

Specifically, the objectives of this project are to:

1. Develop a physical method with the use of high temperature water and activated carbon (AC) for removing the indigo blue colour from cotton denim.
2. Conduct experiments to optimize the conditions of parameters in the method for achieving a target decolouring efficiency ≥ 98% as defined by K/S measurement.
3. Characterise the mechanical strength of the decoloured and the original cotton.
4. Develop a decolouring process and a pre-industrial scale system based on the method.
5. Estimate the operating cost and perform sustainability impact assessment.

It is expected that this project help reduces pollution level in denim production and encourages recycling of denim products.