Scientists at Tomsk Polytechnic University, together with international colleagues, have developed a method to convert polyethylene terephthalate (PET) waste into valuable porous materials for water and gas purification. Plastic bottles, food containers, industrial polyester, and even mixtures of PET with polyethylene can be used as raw materials.
From plastic, researchers obtain special compounds and then create metal-organic frameworks from them — three-dimensional structures with a huge number of microscopic pores. Thanks to this, such materials are capable of capturing pollutants, separating mixtures, and being used in chemical reactions.
The main difference of the new technology is that several stages of processing have been combined into one process. Usually, plastic is first broken down, then the intermediate substance is isolated and purified, and only after that is it modified. At TPU, they managed to reduce the number of operations, decrease the amount of equipment, and thereby lower production costs.
According to researchers' calculations, one of the resulting components can be produced approximately 5–7 times cheaper than its commercial counterpart, and iodine-containing compounds — 75–80 times cheaper. At the same time, materials from waste retained comparable characteristics — microporosity, crystalline structure, and thermal stability.
In the future, such frameworks can be used for water purification from organic pollutants, in the chemical industry, and in catalysis. Now, scientists plan to scale up the process and evaluate the entire cycle — from collecting and grinding plastic waste to producing the finished material.