How to Neutralize Chemical Spills

Neutralizing an acidic or caustic material during spill cleanup makes the material safer to handle and dramatically reduces disposal costs. Strong acids and bases can be very corrosive to many materials, including skin.

How do you know if something is a strong acid or base? The best way to measure this is to take the pH of the solution using pH paper, chemical indicators or pH meters. Chemicals with a pH of 7 are considered neutral.

Acids typically have a sour taste and a pH less than 7. To neutralize them, use a weak base. There are two types of acids: mineral (inorganic) acids such as sulfuric, hydrochloric or nitric, and carboxylic (organic) acids such as formic or acetic.

Bases, also called alkaline compounds, have a bitter or astringent taste and a pH greater than 7. Use a weak acid to neutralize bases. Examples include sodium hydroxide, potassium hydroxide and ammonia.

Many different products aid in the neutralization of acids and bases. They can be as simple as a bag of citric acid or sodium sesquicarbonate, or as complex as a solidifier and neutralizer combined.

The acid and base react during neutralization, forming water and a salt. If the acid and base are both very strong (such as concentrated hydrochloric acid or sodium hydroxide), a violent reaction will occur. That’s why most neutralizers are very weak: to slow the reaction. Even with neutralization products, heat and gas will often evolve. Take proper precautions as recommended by the neutralizer’s manufacturer.

Most neutralizers give an estimated amount of acid/base that they’ll neutralize. It usually takes large amounts to neutralize an acid or base, especially if it’s concentrated. Some neutralizers have a built-in color indicator to signal when the spill is neutral. Others require you to check the pH until it’s neutral. Some neutralizers also solidify the spill as they neutralize to make cleanup easier.

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Source: Lab Safety Supply