Tag: pollution

What’s your biodegradable coffee cup made of – and how biodegradable is it?

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Has your local coffee shop recently switched to biodegradable cups? Or maybe your workplace canteen has made the switch to biodegradable cutlery? Perhaps the plastic packaging of your favourite magazine is now a biodegradable wrapper? You might wonder what materials are behind these biodegradable products, and exactly how much better they are for the environment than the materials they’ve replaced. Here, we explore these biodegradable plastics, and how they stack up against conventional ones.

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The Chemistry of Leaded Petrol, Unleaded Petrol & Diesel

The Chemistry of Petrol & The Tetraethyl Lead Story

Infographic on the chemistry of petrol and diesel. Both petrol and diesel are obtained from fractional distillation of crude oil. Diesel is removed at a higher boiling point and contains a larger quantity of energy per litre. In engines, air and fuel are injected, the fuel is compressed, then combustion of the fuel takes place, with waste gases ejected through the exhaust. Knocking can occur when combustion doesn't occur in sync with the engine cycle, with octane ratings gauging how well fuel avoids this problem. Higher octane ratings indicate less knocking. Compounds added to petrol can boost its octane rating: tetraethyl lead was used as an anti-knocking agent in leaded petrol which has now been phased out. Alternative anti-knocking agents are now used.
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Tomorrow (18th May) marks the date of birth of Thomas Midgley, who made significant contributions to something many of us make use of on a regular basis: petrol. Midgley was the research assistant to Charles Kettering, and the duo were responsible for the addition of the compound tetraethyl lead to petrol. This innovation would have a lasting legacy – although perhaps not in the manner that they may have originally envisioned.

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Brief Guide to Atmospheric Pollutants

A Brief Guide to Atmospheric Pollutants

Brief Guide to Atmospheric Pollutants
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Back in school, you’ll have learned that the air in our atmosphere is composed primarily of nitrogen, at 78%, and oxygen, at 21%, with a number of other trace gases. It’s to these trace gases we’re looking today – more specifically, at how human activity can result in the release of air pollution in to the atmosphere. Here, we examine a number of different chemical compounds that contribute to atmospheric pollution, their specific sources, and their effects.

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