One month to go before the Physics Department closes!  And I have the job of classifying and disposing of unwanted and waste chemicals.  This year, when “everything must go”, this is proving a mammoth task.

How did I get this job?  Being the only practicing chemist in the department, in effect I am Snape, the Potions Master.  This in not only because of my academic training, but my work has taught me what chemical can go with which without creating an explosion (for example, NOT acetone and chloroform!)

Mostly this job involves putting the appropriate hazard label on bottles or jar and relocating them to the outside store for collection by the chosen waste disposal company.  But there are some examples where one can make things simpler.

Fuming nitric acid, for example.  Now one does NOT want to put this in the outside store, where its vapours will slowly eat away the labels on the surrounding bottles.  However, if one pours it gently into a bucket full of water with some caustic soda at the bottom, as below



one is left with a solution of sodium nitrate, which is a fertilizer, and the whole can be diluted with a copious amount of water and flushed down the sink.

Notice the brown fumes of nitrogen dioxide coming out of the bucket.  Not something one wants in high concentrations or in large amounts where it becomes a pollutant.  But it is also produced by lightning, where it enters the nitrogen cycle by forming nitrate, a food for plants.  Much better, in my opinion, to manage things this way than to leave such a hazardous chemical for unskilled workers to collect.