Conservation image Performance of Pollutant Adsorbents (2001–2003)
A project of the Getty Conservation Institute

For a special type of material called a "chemisorbent," a known quantity of gas is passed through a bed of chemisorbent until the pollutant breaks through the bed and can be measured at the outlet. On the right is about 2 grams of purple-red Purafil. On the left is the same material now brownish-black after reacting with about 11 weight % acetic acid. In the middle, 14.5 weight percent of formic acid has exhausted the potassium permanganate (the brownish-black material) and then proceeded to react further with the alumina substrate (the white efflorescence). Photo: Jeffrey Levin.