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Speaker 1: Welcome to Brainstuff from how Stuff works dot com where

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Speaker 1: smart happens. This podcast is brought to you by Audible

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Speaker 1: com slash brain Stuff today for details. I am Marshall

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Speaker 1: brain with today's question. What is activated charcoal and why

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Speaker 1: is it used in filters? Charcoal is carbon. Activated charcoal

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Speaker 1: is charcoal that has been treated with oxygen to open

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Speaker 1: up millions of tiny pores between the carbon atoms. These

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Speaker 1: pores give the charcoal amazing surface area, maybe a thousand

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Speaker 1: square meters or more per gram of charcoal. The word

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Speaker 1: ads orb is important here. When a material adds orbs something,

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Speaker 1: it attaches to it by chemical attraction. The huge surface

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Speaker 1: aery of activated charcoal gives it countless bonding sites. When

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Speaker 1: certain chemicals pass next to the carbon surface, they attached

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Speaker 1: to the surface and they get trapped. Activated charcoal is

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Speaker 1: good at trapping other carbon based impurities organic chemicals in

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Speaker 1: other words, as well as things like chlorine, many other

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Speaker 1: chemicals are not attracted to carbon at all. Sodium nitrates,

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Speaker 1: things like that so they pass right through. This means

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Speaker 1: that an activated charcoal filter will remove certain impurities while

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Speaker 1: ignoring others. It also means that once all the bonding

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Speaker 1: sites are filled and activated charcoal filter stops working. At

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Speaker 1: that point, you have to replace the filter. Do you

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Speaker 1: have any ideas or suggestions for this podcast? If so,

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Speaker 1: please send me an email at podcast at how stuff

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Speaker 1: works dot com. For more on this and thousands of

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Speaker 1: other topics, go to how stuff works dot com