Electrostatic precipitators, Scrubbers and Catalytic Converters Preventing Pollution - Practice Questions & MCQ

Catalytic Converters:

• Removal of pollutants from fossil fuel will be possible by use of catalytic converters in two, three and four wheelers. 
• The catalytic converter has expensive metals like platinum, palladium and rhodium as catalysts. 
• When the poisonous exhaust gases pass through a catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. 
• Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas respectively.
• Motor vehicles equipped with catalytic converters should use unleaded petrol because lead in the petrol inactivates the catalyst.

Electrostatic Precipitators:

• For removing particulate matter from air, electrostatic precipitator is used, which can remove 99% particulate matter present in the exhaust of thermal power plants.
• It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons. 
• These electrons attach to dust particles giving them a net negative charge. 
• The collecting plates are grounded and attract the charged dust particles.
• The velocity of air between the plates must be low enough to allow the dust to fall. 

Scrubber:

• A scrubber can remove gases like sulphur dioxide and ammonia. In a scrubber, the exhaust is passed through a spray of water or lime.