Nitric acid is among the most corrosive and highly reactive acids out there. It can react violently with numerous other compounds and elements, posing a serious threat to human life.
This colorless liquid can cause irritation to your eyes, skin, and lungs upon exposure.
It can also result in pulmonary edema, dental erosion, and bronchitis if the right precautions aren’t taken.
If you’re looking for a way to dispose of nitric acid safely, you’re at the right place. Here is everything you need to know before you get started.
The Safest Ways to Dispose of Nitric Acid
Nitric acid can be a dangerous chemical to handle, and you will need to take great care while disposing of it.
Here are the main steps to follow on how to dispose of nitric acid.
Step 1 – Protect Yourself Beforehand
Before you start the disposal process, you first need to make sure you have all the required PPE (personal protective equipment).
Every exposed surface of your body should be properly covered, including your face, eyes, hands, and clothes.
You will need a face shield (or a gas mask preferred), protective goggles, gloves, and a long lab coat.
Also, open the doors and windows to prevent nitric acid fumes from concentrating within the room. Your area of handling should have good airflow.
Another good practice is to go over all the possible hazards of handling nitric acid beforehand.
You should know of the dangers of using nitric acid, which substances it reacts to the most and what to do in case of an emergency (more on this later).
Step 2 – Dilution is Essential
Now that you’re prepared with the right PPE and all the information you need let’s figure out how to dispose of nitric acid.
If you have a diluted formula, you can dispose of it in small amounts in your sink or through your toilet.
This ‘small amount’ shouldn’t cross 300 ml in one go, and you should follow the nitric acid with copious amounts of tap or distilled water for further dilution.
A helpful trick is to stop your sink using the stopper and pour or collect a gallon of water into it.
Add 300 ml of your nitric acid into this water and then release the plug. Make sure that your skin doesn’t come in contact with this solution while you handle the stopper.
You can use this process in the oiler as well. While the acid-water mixture is draining, keep the tap on so you can continue diluting the acid for the safest disposal possible.
Important Note – under no circumstances should you use mineral water to dilute the nitric acid.
Mineral water has several different components, including organic particles, which can react violently with the acid.
This could pose a threat to the safety of everyone in your surroundings. It is best to stick to distilled or tap water only.
Step 3 – You Might Need to Neutralize First
If you have concentrated nitric acid or a large volume of dilute acid, then the sink technique won’t work.
You can’t pour down a lot of acid into your pipes as it can cause damage and enter your water lines. Instead, you will need to neutralize the acid first then dispose of it.
Disposing of Concentrated Nitric Acid
For proper disposal of concentrated nitric acid, you will have to do an additional step.
This is because the acid is quite strong, and simple dilution steps won’t reduce its reactivity.
Therefore, you need to dilute and then neutralize the acid to ensure it is safe to be disposed of.
Neutralization is a reaction in which an acid reacts with a base to form water and a consecutive salt.
Since you have an acid, nitric acid, you simply need a base in the appropriate amounts and concentration for neutralization.
Some safe bases to use are potassium hydroxide, sodium bicarbonate, and sodium hydroxide.
All of these will produce a nitric salt which causes a color change in the mixture. You can also use this color change as an indication that the neutralization reaction was successful.
With Potassium Hydroxide
An effective neutralizer for nitric acid is potassium hydroxide. You will need to have the ratio of 1:1.12 of nitric acid to potassium hydroxide for complete neutralization.
Measure the volume of nitric acid you have so you can calculate how much potassium hydroxide you’ll need accordingly.
Mix in the two chemicals for neutralization to occur, after which you can safely dispose of concentrated nitric acid.
With Sodium Bicarbonate
It takes one part of sodium bicarbonate to neutralize one part of nitric acid.
So, you can use this scale to measure the amount of sodium bicarbonate you will need for disposal of your nitric acid.
Be sure to slowly pour in your acid in the bicarbonate and not the other way around. Adding bicarbonate to the acid will cause an intense reaction which puts you at risk of acid exposure.
With Sodium Hydroxide
You can use another hydroxide to neutralize your nitric acid, sodium hydroxide. First, you’ll need to dilute the acid with 10 parts of distilled water.
Then, neutralize the acid with equal parts of a 6 M solution of sodium hydroxide. You will notice the solution turning dark yellow or brown.
This is because the neutralization reaction produces nitric oxide.
Safety Tips to Remember When Disposing of Nitric Acid
There are many safety tips you can utilize to ensure the smooth disposal of your nitric acid.
Before starting, always have your protective gear on.
We can’t emphasize enough how essential it is to have your hands, face, eyes, and clothes well covered before you handle nitric acid.
Here are some other safety tips you should follow to ensure safe disposal;
- Remember to never mix organic solvents with your inorganic acids.
- Make sure that your nitric acid is stored in a container that is compatible with its corrosive nature. Avoid metals or any other material that could have organic residue.
- If you plan on storing the nitric acid, you will need to ensure the containers are sealed to perfection. Since inhaling traces of nitric acid in the air can damage your trachea and lungs, you will need to keep the acid container capped at all times. You can even consider getting a vented cap if required.
Steps to Take In Case of an Accident
No matter how careful you are, there is always a risk of something going wrong.
It could be a small splash of the acid, a bigger spill, or an unexpected heat reaction.
Before you dispose of nitric acid, you need to make sure you’re prepared in case an accident occurs.
Here are some emergency procedures offered by Harvard to keep in mind before you start the disposal process.
For Your First Aid
- In case of skin contact, flush that area with tepid water for 15 minutes after removing any jewelry as it could be trapping the acid. Then call 911 for further medical assistance.
- In case of eye contact, use an eyewash and flush out your eyes repeatedly by holding the eyelid open. If there are other people around, request them to call 911 or do it yourself. Continue flushing our eyes until medical help arrives.
- In case of inhalation, immediately move outdoors and take several breaths of fresh air. If you feel an obstruction or burning sensation while breathing, call 911 for further assistance.
- In case of ingestion, directly call 911 and get to a hospital immediately. Don’t try to induce vomiting. If you’ve noticed someone lose their consciousness due to nitric acid ingestion, don’t try to give them something or wake them up. Wait for medical help.
For a Spill Response
- If there is a spill outside a ventilated enclosure, you should alert others in the room immediately and evacuate that area. Block the entry and ensure nobody goes inside the room. Then, call for professional help.
- If there is a spill within your area of handling, check to make sure you have all the required PPE, including a face shield. Then, get an acid neutralizer and follow the steps mentioned above to dispose of nitric acid. Be sure to absorb with polypropylene or a pearlite absorbent once you’ve successfully neutralized your acid.
At the End
Handling nitric acid may be a common part of your usual day, but you have to keep in mind that it is a highly corrosive acid.
There have been numerous incidents reported of severe injuries and dangerous accidents caused due to improper handling of nitric acid.
So, always follow the right protocols and don’t slack off. Before you get started, put on your PPE and keep it on till you have fully disposed of all the nitric acid.
Lastly, go over the precautions to take as well as safety measures to follow in case of accidents repeatedly.
It helps to have these pointers memorized so you can take quick action if ever needed.
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