Q. What is inside a water purifier that is attached to a water faucet?

A. There is activated charcoal and porous paper in many water purifiers. Activated charcoal absorbs impurities and unpleasant smells and is also used to deodorize refrigerators. The paper functions to remove bacteria, mold and iron rust. The porous paper is made up of strings (fiber) with a hole inside like a hose or macaroni as well as holes on the surface. The size of the hole is smaller than one-1,000th of one millimeter and red rust (iron rust) and bacteria (such as coliform bacilli and dysentery bacillus) cannot pass through the holes. However, the components in tasty water, minerals such as calcium and magnesium, are very small in size and able to pass through the openings. That's how water purifiers can remove bacilli and yet provide tasty water.

Such fibers are also used for various products such as suits, carpet and artificial kidney (dialysis care).