Agricultural waste to create sustainable textiles

Making clothing from water-intensive cotton has a major impact on the climate. Cellulose-based textile materials, such as those made from wood, can make clothing more sustainable, yet use many chemicals in manufacturing.

A study headed by researchers from Chalmers University of Technology in Sweden points to the possibility of using agricultural waste from wheat and oat — the method is easier and requires fewer chemicals than manufacturing forest-based cellulose. It can also enhance the value of waste products from agriculture.

The researchers tested oat husks, wheat straw, potato pulp and sugar beet pulp. Oat husks and wheat straw turned out to work best to develop a pulp, called dissolving pulp, which is used to make clothing.

“With this method, which we further developed in this study, we show that you can make textile pulp from certain agricultural waste products,” said Diana Bernin, Assistant Professor at the Department of Chemistry and Chemical Engineering at Chalmers and senior researcher in the study. “This is an important step towards being able to create textiles from waste products instead of using cotton, which isn’t climate-friendly, or wood, a material that we want to use for so many things while also needing to preserve it for the benefit of the climate.”

The team used soda pulping as one part of the process. This means that the raw material is boiled in lye, which makes manufacturing more sustainable.

“Lye doesn’t contain any toxins or substances that impact nature,” Bernin said. “Soda pulping doesn’t work for wood fibres, so making textile pulp from wheat straw and oat husks requires fewer chemicals than making forest-based cellulose. It’s also a simpler procedure, in part because it doesn’t require processing such as chipping and debarking. In addition, it increases the economic value of oats and wheat, when leftovers from their production can be used as raw materials for cellulose extraction.”

Bernin said it is likely that several other agricultural waste products can be used for textile manufacture using the method her team developed. She is currently involved in an international project that has found, using the method in this study, that press-cake from grass from fields works very well to create dissolving pulp.

In continued studies that have yet to be published, the researchers have also taken another step towards practical application of the dissolving pulps, creating textile fibres based on pulp from wheat and the press-cake from grass.

Bernin said the team sees good opportunities to use the pulp-and-paper industry, which already has technology and processes in place, to make dissolving pulp from agricultural waste.

“If we can make use of our existing industry and adjust their processes instead of building new production facilities, we’ve already come a long way,” she said.

The lead author of the study is Joanna Wojtasz, former postdoc at Chalmers and now a researcher at the innovation company TreeToTextile, which is one of the partners in the project.

“The study shows that there is a lot of potential in agricultural waste,” Wojtasz said. “We really shouldn’t disregard the opportunity to use this type of cellulose streams for our future clothing.”

The study ‘Producing dissolving pulp from agricultural waste’ was published in the scientific journal RSC Sustainability.

Image credit: iStock.com/branex