A Novel Method and System for Decolourisation of PET from Post-Consumer Textiles

Decolouring is a common process that takes place before used textiles can be reused or re-dyed. Studies show that under hydrothermal conditions, the PET fibres swell, allowing the dispersed dyes to be released from the fibres. There are also studies indicated that crosslinked polystyrene (PS) beads and activated carbon (AC) particles are effective dye-adsorbent materials.

Accordingly, this project has developed a novel decolourisation method and system which remove the disperse dyes molecules from PET textiles. After the dye molecules are dissolved in the water in the decolourisation system, the dye-containing water is then passed through a standalone column which is packed with AC or PS Beads adsorbents. By a process of continuous circulation, the dye molecules dissolved in water are removed by the adsorbents. The textile products will return to their pre-dyed condition. 


With an over 90 % reduction of colour intensity (K/S value), the approach is effective in decolouring PET textiles. These textiles can then be re-dyed and reused to make new garments, which has the great advantage of helping the textile industry to improve its sustainability by minimising the demand for virgin fibres.

Industry benefit

The new method prolongs the life of PET material in a sustainable way as they can be reused after decolourisation and be made new garment. It alleviates the need for virgin materials in textile production and drives the growth of textile recycling market.

Technological breakthrough

The decolourisation approach is a physical process and involves no chemical reactions.

The cost of the dye adsorbents is low relative to that of current decoloring chemical agents. This standalone column used for decolourisation also allows easy replacement of the packed adsorbents.

The approach can reduce colour intensity significantly and can be effective in decoloring PET textiles in the form of fibre, yarn, fabric or garment.

Licensing Details

A non-exclusive license of manufacturing the decolorization of PET system which decolour the PET fibers from garment recycling, thereby enabling re-dyeing and forming new textiles.


Award Name
Silver Medal in the 47th International Exhibition of Inventions of Geneva (2019)
Related ITF project
Research Start Date 2018-11-01
IP Number