Fashioning cotton gin

Researchers at Deakin University are transforming cotton gin trash into a bioplastic film and creating reuse potential for the global problem of textile waste.   

The fashion industry is one of the largest industrial polluters in the world, with the United Nations Environment Authority estimating that globally, the equivalent of one garbage truck of textiles is burned or sent to landfill each second.

Additionally, War on Waste calculations suggest 6000 kilograms of clothing is sent to landfill every 10 minutes. The ABC program attributes the scale of the problem largely to fast fashion.

The United Nations Environment Authority makes similar arguments, suggesting in a 2018 statement that recycling itself cannot fully address throwaway fashion culture. According to the authority, the number of times an individual garment is worn has declined by 36 per cent in the last 15 years.

Existing within the linear economy of make, use, dispose – throwaway fashion largely conforms to wider patterns of consumption. Dr Maryam Naebe of Deakin University’s Institute for Frontier Materials (IFM) is attempting to address this by studying ways to repurpose the textiles present in throwaway clothes.

Deakin’s IFM was established to develop scientific solutions to some of the major challenges facing waste generation. The institute attempts to do this via scientific and engineering innovation in material design and performance. The aim, according to Maryam, is to develop new materials and structures that are both affordable and possess low social cost.

The focus of Maryam’s research is sustainable approaches to value adding in natural fibres and textiles. Her most recent work centres around a common waste by-product of the textile industry, cotton gin.

Under Maryam’s lead, a team of scientists from IFM, including PhD candidate Abu Naser Md Ahsanul Haque and Associate Research Fellow Dr Rechana Remadevi, have developed a method of turning cotton gin trash into a biopolymer.   

Cotton gin trash refers to cotton waste left over from the ginning process, which involves separating cotton from seeds. The resulting waste stream is a mix of seeds, stems, short fibres and other by-products.

As a senior researcher in fibre science and technology, Maryam noticed the huge reuse potential of cotton gin waste.

“About 29 million tonnes of cotton lint is produced each year, but up to a third of that ends up as cotton gin trash, where it’s then sent to landfill or burnt,” Maryam says.

“After group brainstorming, we realised cotton waste represented a major environmental problem, which created significant losses in material value.”

Maryam and her team’s method for transforming cotton gin trash involves dissolving the waste in environmentally-friendly chemicals. The dissolved biomass then becomes an organic polymer, which can be re-cast into a useable bioplastic film.

Maryam says as a bioplastic, the organic polymer could be used in any throwaway application where synthetic plastics or films are already in use such as packaging, bale wrap and waterproofing supplies.

“Compared to synthetic plastics, our bioplastic is made without the need for toxic chemicals, which makes it safer and cheaper to produce at a mass scale,” Maryam says.

According to Maryam, the repurposed polymer can also be used as a fertiliser.

“The product also has the added bonus of contributing to a circular economy, as it can be placed in the soil to assist the regrowth of its original form,” Maryam says.

“The material is fabricated from a natural biodegradable cellulosic source and is therefore capable of being decomposed by bacteria or other living organisms.”

Maryam says in addition to presenting a sustainable solution to the problem of synthetic plastic, the process could also offer cotton farmers an additional source of income by generating a resale market for cotton waste.

While Maryam and her team feel positive about the scale up potential of their research, she says they are still in the beginning stages.

“Cotton gin trash is challenging to work with. A lot of waste streams are quite homogeneous, containing only one or two different materials,” Maryam says.

“Cotton gin waste however is heterogeneous, and consists of a lot of varied and unwanted material.”

Challenging waste stream aside, the process has already been successfully applied to create a membrane-like wastewater filter. Maryam says the filter has been used to remove dyes from textile manufacturing in wastewater, highlighting the circular aspect of the process.

According to Maryam, current testing shows the bioplastic filter has the same efficiency as charcoal, the current standard for the dye filtration process.

Despite working on the process for only 18 months, Maryam says researchers are now testing the method on other organic waste and fibre material.

She says testing has already produced demonstrated results with lemongrass and hemp, with good progress shown for barley straw and wheat straw.

Given exhibited results, Maryam says the process would not be difficult to up-sell or commercialise. She says however, as with most research, that up scaling requires funding and support, both from industry and government.

“Research projects often get stuck in the infancy stage because they do not get the funding support required,” Maryam says.   

“I would really like to see support for this kind of work, not just for my project, but all research that explores sustainable solutions for waste. If given the support to commercialise, work like this could create real change.”

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