How reverse osmosis can remove all harmful material from water ?

i dnt knw how but RO systems make my water taste really better...i got mine from here..

http://www.isopurewater.com/

i m totally satisfied with it...

I don't know that it can remove all harmful material. The way it works is like a sieve. There's a membrane full of holes that are just big enough to let a water molecule pass through but too small for bigger things like sodium ions and viruses. The water won't just pass through though. A physical force is needed to counter the osmotic pressure that keeps it in solution on the dirty side. The force pushes the water molecules through the holes, sort of like squeezing a wet sponge. This is "reverse" osmosis.