Oxalic Acid is derived from Oxalis plants because of its natural presence in them as in Rhubarb and spinach, it is used to polish floors and also as a cleaning product in some construction materials.
Because it is a material with a certain level of acidity, there is concern about how harmful oxalic acid could be to the materials in a home or to a person’s health.
In this article, I will answer these concerns precisely.
What is oxalic acid, and why is it used as a household cleaner?
Oxalic acid, also known as ethanedioic acid or oxalate, is a reliable and effective cleaning agent. Oxalic acid is an odorless (does not produce smell) chemical compound with a white crystalline appearance in solid form.
When mixed with water, oxalic acid forms a colorless solution. Since oxalic acid has bleach-like properties, it can remove rust and tough stains from boats, concrete, sidewalks, wood decks, iron machinery, building, boats, driveways, swimming pools, and stairs. Oxalic acid is also used in:
• Pharmaceutical industry
• Electron industry
• Organic synthesis
• Dyeing & printing industry
• Extractive metallurgy
• Making teeth whitening products
Oxalic acid has a reputation for its wood bleaching capabilities. Wood tends to fade with time, especially when exposed to rain and sunshine.
If you want to refinish the wood, oxalic acid is the perfect bleaching agent to restore the wood to its natural color.
However, if you are considering using oxalic acid as a cleaning agent, here are some things you need to know:
How Harmful is oxalic acid in housing materials?
Although oxalic acid is used as a household cleaning agent, it is recommended to avoid exposing it to metals for a long time. Prolonged exposure of the acid to irons leads to the leaching of metal ions into the cleaning solution, thus reducing the strength of the metal.
Also, please take caution when using oxalic acid in high concentrations because it can damage some items/materials or surfaces, for example, enameled cast iron.
Use a weaker cleaning solution regularly to avoid damaging some surfaces.
Is oxalic acid harmful to humans?
Oxalic acid is a strong acid that is deemed a poison. Therefore, follow the manufacturer’s guidelines and avoid exposing your skin to the cleaning solution, especially if it is of high concentration.
If your skin is exposed to the cleaning solution, wash it thoroughly with plenty of water because oxalic acid may cause skin irritation or inflammation.
Always take extra precautions when handling dry crystals to prevent inhalation or other forms of exposure. For safety reasons, use personal protective clothing (PPE) like rubber gloves, goggles, a mask, and an overall.
The use of Oxalic Acid without protection of the respiratory tract leads to long-term consequences.
Its pure use for domestic and commercial purposes has been prohibited due to the danger it could represent to health, such that it is necessary to apply it at 50% with other neutralizers and brighteners in paste form to prevent it from being ingested in the form of dust through the respiratory tract.
Will oxalic acid harm concrete?
Most acid solutions disintegrate slowly or rapidly in portland cement concrete, depending on the type and concentration of the acid. Certain acids, such as oxalic acid, are harmless to concrete.
Weak solutions of some acids have negligible effects on concrete. Although acids normally attack and leach calcium compounds from the cement paste, they may not readily attack certain aggregates, such as siliceous aggregates.
Calcareous aggregates often react quickly with acids. However, the sacrificial effect of calcareous aggregate is usually beneficial compared to siliceous aggregate in a mild acid exposure environment or in areas where there is no flowing water.
It is crucial to use oxalic acid in recommended proportions and time. If done correctly, oxalic acid removes stains from concrete with ease. However, the cleaning solution corrodes concrete if you fail to rinse thoroughly.
Always rinse the cleaning solution well and avoid leaving it for long periods.
Does oxalic acid remove rust from concrete?
Yes, Oxalic acid is an effective bleaching agent when used correctly. To remove rust from concrete, mix 4 ounces of oxalic acid in a quart of water to make a cleaning solution. After thoroughly scrubbing and rinsing, the cleaning solution should eliminate rust.
Do you need to neutralize oxalic acid?
Oxalic acid is an acid, and you need to neutralize it before finishing the cleaning task. To neutralize the acid, flood the place, for example, the driveway or sidewalk, with water and baking soda.
Repeat the process twice or thrice to ensure you have thoroughly neutralized the acid.
What does oxalic acid do to wood?
Oxalic acid is used in restoration shops as a bleaching agent to remove rust stains from woods that contain tannin. Typically, woods that contain tannin rust when exposed to moisture, iron, and oxygen due to a chemical reaction.
If the wood has old screws or nails, the surrounding areas turn black, making it unattractive. Luckily, oxalic acid removed rust in a chemical reaction called double displacement.
The rust (iron oxide) reacts with oxalic acid to form iron oxalate, a soluble chemical compound. After thorough cleaning and rinsing with water, iron oxalate rinses away.
Can you pour oxalic acid down the drain?
After using oxalic acid for a cleaning project in your home, proper disposal of the acid is vital. Oxalic acid is classified as a Class A organic compound. Therefore, although oxalic acid is an acid, it is biodegradable if diluted and appropriately neutralized.
You should not pour oxalic acid down the drain in its concentrated form. Instead, follow these steps before pouring it down the drain:
• Pour oxalic acid into a large container with ice water (remember to pour the acid into the water to avoid splashing or boiling)
• Neutralize the acid by adding baking soda. The acid will start bubbling after adding baking soda, which is a chemical reaction. Pour baking soda slowly until bubbling stops.
• Test the pH of the neutralized solution using litmus paper. A pH of 5.5 is okay, but you can continue pouring baking soda to neutralize the acid until you get a pH of 7.0 (neutral)
• In its neutral state, oxalic acid does not pose any toxicity hazard. You can then safely pour it down the drain.
What can you use instead of oxalic acid?
Besides oxalic acid, there are other alternatives, although they are more volatile and riskier to handle. Common oxalic acid alternatives include sulfuric acid, hydrochloric acid, and nitric acid. Be cautious because these acids are highly corrosive and poisonous fumes.
Is vinegar the same as oxalic acid?
No, Vinegar and oxalic acid are different compounds, and they have other uses. Vinegar is composed of acetic acid and water, making it a weaker chemical compound than oxalic acid.
Even though many rely on oxalic acid as a household cleaning agent, knowing how to use it is crucial. This caustic chemical is poisonous and harmful when ingested/swallowed.
Therefore, it should be kept out of children’s reach! Always wear protective clothing to protect your skin and eyes when using the product because it can cause skin irritation, inflammation, and eye damage.
Always wash the skin thoroughly after handling the oxalic acid, and avoid drinking or eating food when handling the product. Finally, proper storage and disposal of oxalic acid are crucial to prevent unwanted accidents or effects.
Please read the manufacturer’s instructions and follow them when using oxalic acid to clean items or surfaces at home.