In: Chemistry
How do you dispose the following chemicals:
1. Phosphine Gas
2. Sodium Cyanide
3. Arsine Gas
Phosphine gas: Phosphine gas reacts with water and detergent and decomposes in it hence, a solution of detergent and water which should have a pH value of at least 8 but should not exceed a pH value of 10.5 should be good for disposal. The gas also decomposes in warm air, so passing the gas through the warm air could also be a disposal solution as fully reacted gas is safe for disposal at a suitably approved site.
Sodium cyanide: Mix the Sodium cyanide with dilute sodium hydroxide solution (0.1 to 1 mM) in the hood and collect the rinse as cyanide waste and Dispose of the rinse as hazardous waste. All waste must be disposed of in liquid-tight containers.Cyanides must be detoxified to harmless waste before disposal. Treat the waste with alkaline sodium hypochlorite (<1g/L) in excess.
Arsine gas: Traces of arsine are best removed by absorption in potassium permanganate solution or bromine water. another method could be passing the gas through 15% aq. solution of NaOH and neutralize the solution with 1M H 2SO4 and add 1M Na2S and dispose of the precipitate with 50times its volume of water