Graphene: Solution for the Plastics Problem
Plastics, plastics… The environmental problems and pollution caused by plastic products that may not be easily expelled out of our lives, from the clothes we wear to the kitchen utensils, from food packaging to bedrooms and workspaces, are subjects that scientists constantly work on.
The inefficiency of standard recycling systems (the inability to recycle all plastic types, recycling percentage of total plastic waste, economic concerns, and the low quality of recycled plastics) demands new solutions and innovative perspectives for the plastic problem. While some studies continue to focus on organisms that can decompose plastics (scientists have developed a different method and succeeded in transforming plastic waste into a high quality form of “graphene”, known as the material of the future. Besides, at a much-reduced cost than standard recycling.
In the adventure of converting plastics into graphene, a technique called the “flash Joule heating” is used. It is actually a relatively simple method, consisting of rapidly heating plastic materials to very high temperatures by using an electrical current. The chemical structure of the plastic changes when it’s suddenly exposed to very high temperatures under the right conditions. However, in order to do this, the material must first be cut into small pieces in ideal sizes enough to conduct electricity. The material is then subjected to an extremely high current and low quality graphene is obtained (this process also releases plenty of hydrogen that can be used as fuel). When the same process is applied again to this low quality graphene, the desired high quality graphene is produced. The key point of the process discovered by the researchers at Rice University is to apply alternating current (about 8 seconds) to the already-cut plastic material first. The rapid intercooling stages in between pulses prevent the resulting graphene layers from stacking into layers. After this stage, even higher levels of direct current are applied for half a second, and the low-quality material turns into graphene with the desired properties, strong and flexible. Scientists have also discovered, through trial and error, that in order to conduct electricity ideally, the plastic materials must be divided into pieces of 1-2 mm.
The researchers emphasize that this method is largely superior to other recycling systems. First of all, there is no need to expose plastic waste to any form of chemical treatment. Since the heating is carried out with electricity directly applied to the material, large furnaces are not required for melting. The waste only needs to be cut into small enough pieces. According to the researchers, the cost of converting 1 ton of plastic waste into graphene with this method is about $125, which is lower than other recycling methods.
Obtaining graphene from the plastic waste piling the landfills is an advantage in itself. Graphene is a biodegradable material, which is a process that takes hundreds of years. Therefore, this recycling method can provide both ecological and economic benefits, while also reducing carbon emissions from fossil fuels that cause global warming.
The studies indicate that the industrial usage rate of graphene will increase by 40% over the next five years. Being many times stronger than carbon fiber, graphene is likely to be used extensively in the automobile and aviation sectors. However, the dreamy properties of graphene could only be determined at the nanoscale for the time being. Therefore, experts say we still need to wait for years until graphene becomes a part of our daily lives. However, according to James Tour, a researcher at Rice University, if graphene can achieve what it promises in the field of technology, you will be able to “roll up your iPhone and stick it behind your ear like a pencil.”
- 1. https://www.sciencedaily.com/releases/2020/10/201030092250.htm
- 2. https://massivesci.com/articles/plastic-recycling-graphene-flash-joule-heating/
- 3. https://evrimagaci.org/grafen-nedir-malzeme-biliminin-nobel-odullu-basarisi-7568