Nitric acid is a highly toxic and corrosive acid that has an important role in a plethora of industries such as plastics manufacturing, textile and fertilizing industries. "Aqua fortis" and "aqua valens" are additional terminologies for nitric acid, meaning "strong water" and "spirit of fire," respectively. Being such a powerful chemical, nitric acid must be disposed of in a proper manner.
Disposing of Nitric Acid
Put on gloves to protect your hands and skin; butyl rubber, neoprene and polyethylene are the best skin protectors when dealing with the acid. Put on a gas mask and wear long clothes and protective goggles. Open all the windows in your bathroom and nearby rooms. Open all doors to create air flow.
Small amounts, under 300 ml, of dilute nitric acid can be disposed of down sinks or toilets as long as there is a large quantity of water used to further dilute the acid. Stop-up your sink using your stopper. Pour a gallon of water in the sink. Pour your dilute solution in the water and release the stopper. This same process can be repeated using a toilet. As the acid is draining, continue to further dilute the water with an additional gallon of filtered water. Do not use mineral water. The minerals in the water could have a violent reaction to the acid.
Concentrated nitric acid or large amounts of dilute nitric acid cannot simply be diluted and poured down the drain. It must first be neutralized with sodium bicarbonate. This chemical process is not safe to perform at home. Go to your local city or county's website and find the Poison Waste Management Group or Poison Control Center. They will tell you how to store the materials until they can pick it up for proper disposal.