October 4, 2024

Salt and “Baking” – Simple Combination Solves a Serious Environmental Problem

Chemists from the University of Copenhagen produced a green technique to recycle polyester utilizing hartshorn salt, providing a development in textile recycling. Above is depolymerized plastic from the polyester material. Polyester ranks as the worlds second most used textile, nevertheless, it is an ecological menace, specifically since many of it never gets recycled. Recycling polyester poses a considerable difficulty, particularly in separating the plastic and cotton fibers that the blend fabric is made of without losing either of them in the process. With our newly found strategy, we can depolymerize polyester into its monomers while concurrently recuperating cotton on a scale of hundreds of grams, using a environmentally friendly and extremely simple technique.

Chemists from the University of Copenhagen developed a green approach to recycle polyester utilizing hartshorn salt, using a development in fabric recycling. Above is depolymerized plastic from the polyester material. Credit: Bettina Illemann Larsen/University of Copenhagen
Polyester ranks as the worlds 2nd most used fabric, however, it is an environmental threat, especially because many of it never ever gets recycled. The material, a blend of plastic and cotton, has actually been challenging for the market to separate and therefore recycle. A group of young chemists from the University of Copenhagen has actually created a green and surprisingly simple solution utilizing a single household active ingredient.
From clothing to sofas to curtains, polyester controls our daily lives, with a staggering 60 million lots of this popular fabric produced annually. Nevertheless, polyester production takes a toll on the environment and the climate, as only a simple 15% of it is recycled, while the rest winds up in garbage dumps or incinerated, being responsible for more carbon emissions.
Recycling polyester postures a considerable obstacle, particularly in separating the plastic and cotton fibers that the blend fabric is made from without losing either of them at the same time. Standard recycling approaches frequently prioritize maintaining the plastic element, resulting in a loss of cotton fibers. These approaches are pricey, complicated, and produce metal waste due to the usage of metal catalysts, which can be cytotoxic and contaminate the process.

Yang Yang, Jiwoong Lee and Shriaya Sharma in the laboratory. Credit: Bettina Illemann Larsen/University of Copenhagen
In an exceptional breakthrough, a group of young chemists has revealed a remarkably basic service to this pressing issue, potentially revolutionizing the sustainability of the fabric market.
Currently, there are extremely few useful approaches capable of recycling both cotton and plastic– its normally an either-or scenario. With our newly found technique, we can depolymerize polyester into its monomers while at the same time recuperating cotton on a scale of hundreds of grams, utilizing a environmentally friendly and incredibly uncomplicated method.
Hartshorn salt and 24 hours in the oven.
The brand-new method needs no special devices– just heat, a non-toxic solvent, and a common family component.
” For example, we can take a polyester gown, sufficed up into little pieces, and location it in a container. Add a bit of mild solvent, and thereafter hartshorn salt, which numerous people understand as a leavening representative in baked items. We then warm everything up to 160 degrees Celsius and leave it for 24 hours. The result is a liquid in which the plastic and cotton fibers settle into distinct layers. Its a basic and economical process,” explains Shriaya Sharma, a doctoral student of the Jiwoong Lee group at the Department of Chemistry and study co-author.
Intact cotton fibers after the process. Credit: Bettina Illemann Larsen/University of Copenhagen.
The combination of ammonia and CO2 acts as a catalyst, triggering a selective depolymerization response that breaks down the polyester while protecting the cotton fibers. Ammonia is toxic in isolation, when integrated with CO2, it ends up being both safe and ecologically friendly for use.
Formerly, the exact same research study group showed that CO2 might work as a driver for breaking down nylon, to name a few things, without leaving any trace. This discovery inspired them to check out the use of hartshorn salt. The researchers were pleasantly amazed when their basic dish yielded effective outcomes.
” At initially, we were thrilled to see it work so well on the PET bottles alone. When we found that it worked on polyester material as well, we were just ecstatic.
A polyester material gown cut up into little pieces and put in a container with hartshorn salt and mild solvent. Credit: Bettina Illemann Larsen/University of Copenhagen.
While the approach has only been tested at the lab level therefore far, the researchers point to its scalability and are now in contact with business to evaluate the technique on a commercial scale.
” Were wishing to advertise this technology that harbors such great potential. Keeping this understanding behind the walls of the university would be a huge waste,” concludes Yang Yang.
Shriaya Sharma and Yang showing the approach. Credit: Bettina Illemann Larsen/University of Copenhagen.
Pet and polyester.
Family pet is the most commonly utilized type of plastic worldwide. The production of PET, a plastic most familiar to us as beverage bottles, totals up to 70 million heaps each year and is growing every year. One-third of global PET production is utilized to produce polyester and other synthetic textiles.
Works on waste.
The brand-new recycling technique based on hartshorn salt (ammonium bicarbonate) works on PET plastic alone, as well as on PET and cotton blended materials.
” If we toss dirty plastic waste in a container, we still get good quality cotton and plastic monomer out of it. This can even be a plastic bottle with juice residue still in it.
Referral: “Catalytic Fabric Recycling: Glycolysis of Blended PET with Carbon Dioxide and Ammonia” by Yang Yang, Shriaya Sharma, Carlo Di Bernardo, Elisa Rossi, Rodrigo Lima, Fadhil S. Kamounah, Margarita Poderyte, Kasper Enemark-Rasmussen, Gianluca Ciancaleoni and Ji-Woong Lee, 17 July 2023, ACS Sustainable Chemistry & & Engineering.DOI: 10.1021/ acssuschemeng.3 c03114.