With environmental movements to ban grocery bags and drinking straws, it seems that to the public eye “plastic” has become a dirty word.
Natural ecosystems are harmed by the large amounts of plastic waste produced, but to society today, plastic is irreplaceable. The material is light, cheap, and extremely versatile. The challenge, then, is not to eliminate the use of plastic, but to engineer ways for plastic to be more environmentally efficient, while also remaining convenient for consumers. Recycling processes have made significant advancements, such as the achievement of Japanese company Teijin Limited in 2002, pioneering a new method for recycling single-use plastic water bottles. This technology was a milestone in the research of recycling, a continuing project to make the world a cleaner, safer place to live.
Polyethylene terephthalate (PET) is a common plastic due to its functionality and varying uses. Disposable beverage bottles are most often made of PET because PET bottles are lighter and more durable than glass bottles of the same volume. The clarity of PET and its ability to act as a barrier against moisture are other properties that make PET the choice material for beverage bottles. Additionally, PET can be spun into fibers that are used in carpets, seatbelts, medical garments, and diapers. Its utility makes PET one of the “most widely produced synthetic [fibers] in the world” and also the “most widely recycled plastic” (Encyclopaedia Britannica). Because the use and recycling of PET is so common and widespread, the improvement of recycling processes is extremely important.
The work of Teijin scientists and other chemical engineers brought great advancements in the recycling of PET. In the past, it was not possible to recycle plastic for use in food packaging because there was no efficient process for decontamination. Traditional recycling processes for PET involved chemicals like caustic soda to clean the plastic. However, washing in caustic soda allowed for “only surface cleaning of the post-consumer PET material” (Welle). Advancements created the super-clean recycling process, which involves parts of the traditional process, but decontaminates the recycled plastic to the purity levels of virgin PET. The technique perfected by Teijin in 2002 takes recycled bottles and recovers dimethyl terephthalate (DMT) equal in quality to DMT produced from crude oil. DMT can then be converted into terephthalic acid (TPA) which is used to make PET for new bottles (Chemical Engineering Progress). This is what is referred to as “bottle-to-bottle recycling”. The cyclical process reduces plastic waste because rather than be put in a landfill, a used bottle can be recycled and used again.
Plastic recycling has progressed immensely, but of course there is always room to go further. For example, machines have been created that can sort different types of plastic using infrared sensors. This technology needs to continue to be developed so that it can be a cost-effective way to improve the efficiency of recycling plants. It will also encourage more consumers to recycle if they do not need to be concerned about sorting their plastics. Another idea is to focus efforts into upcycling PET. As written in Teijin’s 2005 sustainability report, the key to creating a recycling-oriented society is emphasizing the concept of “Reduce, Reuse, Recycle”. The flaw of the bottle-to-bottle process is that while it is a triumph in recycling, it does not reduce the use of single-use plastics. Rather than only be made into new bottles, recycled PET should be put toward other applications of the material. Recycled bottles could become fabric for clothing or carpeting for homes. Current recycling processes could become a much greater benefit to society than just bottles.
The world is full of landfills and poverty, but it is the achievements in technology that point toward a better future. It is hopeful to think that a plastic bottle could end up not as trash, but as a fabric to clothe someone in need, or as a carpet in a house to keep someone safe. The continued research of recycling technology is how to heal a crowded planet.