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How to Dispose of Nitric Acid
In this article, we’ll address specifically how to dispose of nitric acid. Like most acids, nitric acid can be neutralized prior to disposal. This chemical reaction greatly reduces the hazardous risks of nitric acid, helping your business to comply with the three tenants of proper waste disposal. The reaction must be completed safely, which we’ll explain in this article.
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Lab Alley
Proper disposal of chemical reagents is essential for three reasons:
- Legal complianceWorker and environmental safety
- Minimizing business/laboratory expenses
- All labs and businesses working with hazardous chemicals must comply with the regulations set in place by OSHA (Occupational Safety and Health Administration) and local jurisdiction.
These regulations are in place to minimize risks to workers handling hazardous chemicals.Chemical waste disposal can be expensive for labs and businesses. Businesses must schedule waste pick-up from a hazardous waste disposal company. Minimizing your hazardous waste is one way to cut business costs. It will also reduce costs from replacing expired or spilled reagents.
What is nitric acid?
Nitric acid is one of the seven strong acids. It has the chemical formula HNO3. As a pure compound, it is a colorless liquid. As it begins to degrade, it takes a yellowish hue due to the accumulation of other nitric oxides. For example:4HNO3 → 2H2O + 4NO2 + O2Nitric acid is hazardous due to its strong oxidizing and corrosive properties.
When do you need to dispose of nitric acid?
Nitric acid may need to be disposed of if it has degraded, and/or if it is past its expiration or shelf life. Excess reagent that is not useful will also need to be disposed of to mitigate hazard risk. It is important to keep careful inventory and not order surplus chemicals to avoid this situation.
How long does nitric acid last?
Nitric acid is generally thought to have a shelf life of 1-3 years, if stored according to the manufacturer’s indications. Exposure to heat and light will hasten the degradation of the product, and should be avoided. It is also important to realize that sealed, unopened nitric acid will last much longer than a partially used bottle.The shelf-life of the storage container itself may also be an important factor. Nitric acid is often sold in a material called HDPE, or High Density Polyethylene. There is a modified form of HDPE designed to be more resistant to nitric acid. The manufacturer’s recommended shelf life and expiration date account also for the durability of the bottle, which can also degrade over prolonged storage periods.
How to dispose of nitric acid
The safest and cheapest way to dispose of nitric acid is by first diluting (if it is a very concentrated solution) and then neutralizing by addition of a base. Options for neutralizing bases include, but are not limited to:
- Sodium hydroxide
- Calcium hydroxide
- Magnesium oxide
- Ammonia
- Sodium bicarbonate
Acid-base neutralization results in the formation of water and a salt. For example, if sodium hydroxide is used to neutralize nitric acid, the following reaction will occur:HNO3 (aq) + NaOH (aq) → H2O (l) + NaNO3 (aq)In this case, the salt formed is sodium nitrate. This new salt water solution is no longer considered hazardous waste, and can usually be safely disposed of down the drain. Naturally, you should always check with regulations for chemical waste disposal in your local jurisdiction.
To perform the reaction, first ensure you are wearing the proper personal protective equipment, including splash goggles, gloves, and a lab coat. Work in a well-ventilated space, such as a fume hood if available. Next, dilute the concentrated nitric acid (if necessary) by adding acid to water. This will greatly reduce the risks associated with potential spills.
When you are ready to begin the chemical reaction, have the acid in an acid-resistant container to start. Calculate how much base you should theoretically add to the acid in order to achieve neutralization. You should also use a pH meter or pH paper to monitor the reaction to completion. Aim for a neutral pH, and be careful not to overshoot, as this will result in a new kind of hazardous waste material. The neutral salt water solution should be ready for safe disposal down the drain.
Where to restock on nitric acid
Now that you’ve disposed of your expired or degraded nitric acid, you will need to restock with a high-quality replacement from a supplier you trust. Lab Alley offers high quality nitric acid at competitive pricing, with a no-hassle ordering process, and fast delivery.
Conclusion
Chemical waste disposal can be expensive for labs and businesses. Businesses must schedule waste pick-up from a hazardous waste disposal company. Minimizing your hazardous waste is one way to cut business costs. It will also reduce costs from replacing expired or spilled reagents.