what is platinised asbestos???????????????

what do we mean by activity  n desorption??????????????///  pls help............

Asbestos is a silicate mineral which shows good adsorption properties.  Asbestos whose outer surface is coated with platinum is called platinised asbestos. 

By activity, we basically mean the action (mode and functioning) of a substance. For example, by activity of a catalyst we mean that how the catalyst functions and catalyses a  reaction. To enhance the activity of a catalyst means to enhance the ability of a catalyst to catalyse a reaction. It is an important feature of solid catalyst and depends upon the extent of chemisorption to a large extent. The process by which an adsorbed or absorbed substance is removed from or through a surface is known as desorption. It is simply the opposite of absorption or adsorption.