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Discount will be applied automatically at checkout. Your account has been created successfully, and a confirmation email is on the way. Giordan elected ACS president-elect. Most plastics are recyclable, but are not actually recycled.
One way to encourage recycling is to make plastics from polymers that can be chemically recycled, or broken down into monomers that can be recovered and made into new polymers.
Coates presented a polymer that can be broken down into monomers and recovered from a mixture of plastics Science , , DOI: The monomers, including 1,3-dioxolane and derivatives, are liquids at this temperature. Abel, a polymer chemist now at the University of California, Berkeley, who helped develop the new plastic. The new polymer could be used as a packing material, collected, broken down into monomers at a factory, and then reused.
The key was adding a pyridine proton trap to grab excess water from the reaction. When these polymers are heated, instead of changing structure they actually undergo a chemical change. Once they form the first time, they can never be reformed even when heated. Thermoplastic polymers are easy to recycle. Thermosets can be recycled, but not nearly as easily.
The Society of the Plastics Industry has established a numerical coding system to identify which types of plastic are which. This system is necessary for recycling because certain types of plastics are only safe or useful for certain types of products. There are six main types. PETE is mostly found in beverage containers because it is waterproof. It can be spun into carpets, pillows or jackets.
It is most commonly found in plastic bags, oil and detergent bottles, and toys. It is one of the simplest polymers to recycle. It is broken down into flakes, decontaminated and then reused for pipes, flower pots or reused as non-food bottles. It is found in food wrappers and vegetable oil bottles.
It has similar properties to HDPE so it is no surprise that it can also be found in some plastic bags as well as shrink wrap.
When it is recycled, it is grinded into a thin film and then reused for trash bags, agricultural film and plastic tubing. Number 5 is PP, or Polypropylene. This means it's compostable and it can be broken down by the result of bacterial action when it is disposed of.
Whilst this is a benefit, there are still issues with bioplastics that need solving. Bioplastics often come from renewable raw materials like starch, maize, cellulose, and polylactic acids. These are plant-derived materials and so the ethical question arises is where the land should be used to grow crops or bioplastic manufacture instead of crops for food?
Originally we said that bioplastics are readily compostable, however, bioplastics are not nearly as readily compostable as regular plant material. If you toss a bioplastic fork into your compost and assume it will be dirt in a few months you'll be disappointed. Whilst a bioplastic fork is compostable it requires high-intensity high heat commercial composting for that to happen quickly. In summary, plastic disposal has a number of issues with regards to landfills, recycling, and incineration.
However, bioplastics so slightly better do not present themselves as the better alternative because there are issues of land usage, the quality of the bioplastic, and how it is composted.
The best alternative is to reduce our usage and disposal of plastics altogether. In the previous video, the incineration of waste was discussed. Incineration leads to a huge volume reduction of waste, which results in less waste ending up in the landfill.
Waste in the landfill is the least environmentally friendly option. However, incineration typically results in less recycling, which would be a more efficient use of recyclable material than incinerating it. This reduction of recycling due to incineration is considered the major disadvantage of incineration. Although an important concern with incineration is the production of toxins, with proper technology these toxins can be managed.
A segment of the video for this week, Making Stuff: Cleaner , discusses burning waste to create electricity. Please watch the following short video which discusses burning waste to create electricity as well as the issues regarding incineration discussed above. In this video, we're going to consider the advantages and the disadvantages to waste incineration. What do you think are the advantages of burning waste instead of committing it to the landfill?
Pause the video and continue when you have an idea or some ideas. If the waste is not burned, then it is likely to end up in a landfill site which is considered to be the least environmentally friendly option. Incineration could result in a reduction in the waste volume of around ninety percent and this could be particularly important for small cities where space is scarce and landfill is not an option.
Odors and rodents are present in other methods, are not a problem when using incineration as a garbage disposal method. Nearly all of the waste that is burned could be used to generate electricity in what is called energy-from-waste schemes where households and industries could benefit from the electricity or heat produced.
The electricity generated could help to pay for the startup costs of the incinerator. Additionally, the steam produced from incineration presents itself as a cost-saving energy source if recycled. Ash produced from these incinerators could be used in the construction and road-building industries. In addition, metals could be extracted from the ash and they could also be used in steel industries.
The key advantage, however, is that the production of electricity and thermal energy from waste enables us to conserve conventional sources of energy such as fossil fuels? Now, what about the disadvantages of incineration?
Again pause the video and think about what these could be. Resume when you have an idea or some ideas. The main disadvantage surrounds potential pollutants found in the ash left in the incinerator and those that could be emitted from the chimney. These include dioxins, acid gases, nitrogen oxide, heavy metals, and particulates.
As you may have heard from other videos, these are airborne particles that are small enough to get into the lungs of humans. They cause and aggravate respiratory problems such as asthma; however, it is the dioxins resulting from incomplete combustion contained in the gases from the chimneys that attract the most concern. This is because they are suspected of causing cancer. In addition, these emissions could be distributed through the food chains and accumulate over a long period of time impacting both ecosystems and human health.
As a result, many people are opposed to having incinerators built in or near their communities. Another disadvantage is the initial startup costs to build a waste incinerator for the production of electricity and may not be seen as a viable alternative.
Where cheaper waste disposal methods exist, once built the maintenance of the machinery could be costly. The biggest disadvantage, however, is that if waste is incinerated without first being sorted this means we are incinerating waste that could have been recycled. So in summary, the incineration of wastes presents numerous advantages. One, the energy is used the heat or to produce electricity for homes in the industry. Two, this method reduces the need for fossil fuel consumption.
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