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Polymer Problems
recycling etc
Question | Answer |
---|---|
What are the current methods for disposing of polymers? | landfill, incineration and recycling |
Why can we not continue to use landfill as a method? | UK landfill space will run out |
Why should plastics be recycled? | non biodegrability |
Problems with recycling. | plastic waste contains heavy metal ions and colourants |
Why is simply reusing plastics better? | no processing therefore saves energy and oil resources |
First stage of recycling | sorting (using optical scanning techniques) |
Why is it important to sort the plastics? | distinguish PVC as when heated releases toxic dioxins |
Second stage of recycling | reclamation (processing into small flakes before washing) |
Alternative use for waste polymers | burning under controlled conditions to generate electricity |
Another alternative use | feedstock recycling, convert polymers into synthesis gas to then use as a chemical feedstock |
Problems with PVC recycling | high chlorine content makes PVC recycling uneconomical end product costs more to recycle than manufacture from crude oil |
What happens to PVC instead? | PVC is incinerated to prevent from entering landfill |
Problems with PVC incineration | create acidic hydrogen chloride fumes resulting in toxic fumes and corrosion in the plant |
What does the plant do to minimize these problems | plant is fitted with pollution control apparatus to minimise release. |
What are bioplastics | plastics that are biodegradable or compostable |
What are bioplastics made from? | starch, maize, cellulose and lactic acid. |
How do bioplastics degrade? | bacterial activity |
What do bioplastics degrade to? | carbon dioxide and water |