Derek wrote:

It was open stage night in rec.food.drink.tea, when crymad stepped
up to the microphone and muttered:

Don't Brita filters remove chlorine themselves?

Their packaging says they do. But I'm not certain about the
chemistry involved. Anyone here with expertise on the matter?

Activated carbon filters remove a lot of stuff. Pur filters don't
claim to remove ALL chlorine, just reduce it in the water. Brita is
probably the same.

The following is from an aquarists' site regarding the use of
activated carbon in aquariums.

"A particle of activated carbon is mostly air. It has thousands of
tiny holes and crevices through which water can circulate. When
water carries an organic molecule – a contaminant – into these
narrow passages a short range attractive force between the molecule
and the carbon will become effective and the molecule sticks. This
particular method is called physical adsorption. The other kinds of
adsorption also involved with activated carbon are of only minor
importance to the aquarium."

Is it safe to say that chlorine is absorbed the same way? If so, then
our method of removing the chlorine in water by letting it sit out
before transferring to the Brita pitcher would seem to account for the
extended lifespan of the filters.

--crymad