In this case, the use of plastic represents a ‘reversible’ reaction – you can make plastic, and then recycle the plastic to make more plastic. Of course, there’s always a big hairy “but” in situations like this. Sounds great, doesn’t it? The thermodynamic restrictions of human hope As a result, the use of the bottle becomes ‘circular’. What the ‘circular economy’ idea would propose in relation to PET plastic bottles is: Take some natural gas (yes, contrary to the idea that plastics come form oil, most plastics are made from the light by-products of oil refining, but mostly natural gas and gas condensate) and turn it into PET plastic then make a plastic bottle with a blow-moulding machine use the bottle then recycle the bottle, and keep recycling after each use – obviating the need to use more natural gas to create plastic. The Second Law deals with irreversible reactions – that is, operations which once undertaken cannot be undone. Over time science has perfected the principles of these ‘laws’ and now finds that they are universal. The Laws of Thermodynamics arose in parallel with industrialization, having first been used to described the operation of steam engines. One which I would whole-heartedly support, but for one slight technical hitch I perceive in this concept The Laws of Thermodynamics – and my particular favourite, The Second Law of Thermodynamics. ‘Circular’ economy – meaning that all materials and products are manufactured and sold so that their content can be fully recycled and used in new products once more, obviating the need to produce new resources to replace them.‘Linear’ economy – meaning that materials are created, used and disposed as waste, requiring that new resources must be reduced to replace them, which is how the core of the global economy works today.The scientist then described the value of this enzyme as part of the ‘circular economy’ – a concept proposed in the 1980s, and popularized in recent years by organizations such a the Ellen MacArthur Foundation, of moving from a linear to a circular economic process: Great idea and if shown to be ecologically safe, great chemistry. In this case, the enzyme breaks down the bonds of the polyethylene terephthalate (PET) molecule. As with all enzymes – like the things they add to washing powder so you can clean clothes without boiling them – these complex molecules accelerate chemical reactions by working on the chemical bonds which hold things together. They’ve found a ‘mutant’ enzyme from bacteria they found living on plastic in recycling centres. The segment was examining the new research from Portsmouth University. My problem is that the way they describe it has little to do with the physical realities of the world, and hence it’s really just a “get out of hell free” card for affluent consumers – who are, it would appear, the most vociferous proponents of this idea.Īs is so often the case with feel-good eco-stories, the Today programme’s interviewer was all light and fluffy and obviously flummoxed because they did not have the confidence to ask any basic, challenging questions of the interviewee. It’s a great idea, and I can’t fault the true belief of those promoting it. Listening to Radio 4 this morning I heard the two juxtaposed keywords that I’ve learned to dread over the last couple of the years ‘circular economy’. Why the latest buzz-phrase in consumer sustainability is not only failing to tackle the core problem, but why it is doomed to fail

Pcal thermodynamics ycal