IIT Mandi develops eco-friendly method to recover glass fibres

The method developed by researchers will lead to a profound shift in recycling technologies which can help the country move towards a circular economy for wind turbine blades.

Researchers at the Indian Institute of Technology (IIT) Mandi have used microwaves to recycle polymer composites to make wind turbine blades. The method is rapid, sustainable and eco-friendly compared to currently used methods such as landfills, thermal-based recycling, etc.  

Microwave-assisted chemical recycling  

The findings of the research have been published in the journal, ‘Resources, Conservation and Recycling’. Sunny Zafar, who led the research, said, “We have developed a sustainable microwave-assisted chemical recycling (MACR) process to recycle glass fibre reinforced polymer (GFRP) composite waste. Also, we used microwaves to aid the chemical degradation of GFRP composites with hydrogen peroxide and acetic acid. Both hydrogen peroxide and acetic acid are eco-friendly chemicals, the former used extensively as a disinfectant/antibiotic and the latter being vinegar.” 

2L tonnes waste to be generated by wind turbine blades between 2024 and 2034  

At the end of the service life of the wind turbine blades, the de-commissioned structures, composed of glass fibres in epoxy polymers, are demolished and either landfilled or incinerated. Both methods of disposal add to environmental pollution and cost. It is predicted that about 2 lakh tonnes of composite waste would be generated by wind turbine blades between 2024 and 2034 all over the world. This negates the environmental benefits offered by wind energy. Furthermore, restrictions on landfill disposal and fluctuating raw material costs could increase the costs of these composites used in wind turbine blades.  

Talking about benefits of the research, Venkata Krishnan, School of Chemical Sciences, IIT Mandi, said, “The recycling method that we have developed can lead to a profound shift in recycling technologies, which can help the country move towards a circular economy for wind turbine blades.”  

IIT Mandi team have developed a rapid and eco-friendly method to recycle the fibres present in the composites used in making wind turbine blades. A particular uniqueness of this work was that no harsh chemicals were used in the extraction and the green-chemistry approach was used.  

The researchers found that the decomposition rate of epoxy in our method was 97.2 per cent with recovery of the glass fibres. The recovered glass fibres were tested and their properties were compared to those of virgin fibres. The recovered fibres retained nearly 99 per cent of the strength and greater than 90 per cent of other mechanical properties as compared to the virgin fibres. 

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