Ammonium sulfate

Ammonium sulfate (IUPAC name: ammonium tetraoxosulfate (VI)), is an inorganic compound with the formula (NH4)2SO4. It is a white crystalline solid and is highly soluble in water. Its most common use is as a soil fertilizer. It contains 21% nitrogen and 24% sulfur.

Production

The synthesis of ammonium sulfate is straightforward and can be accomplished through several methods. The most common method involves the direct reaction of sulfuric acid with ammonia: \[2 NH_3 + H_2SO_4 \rightarrow (NH_4)_2SO_4\]

Another method is the recovery of ammonium sulfate from the by-products of the coke-making process, also known as the Gypsum process.

Uses

Fertilizer

Ammonium sulfate is primarily used as a nitrogen fertilizer in agriculture. Its solubility provides versatility for a number of agricultural applications. Its nitrogen content is useful in promoting plant growth, which makes it popular for gardens, lawns, and crops.

Chemical Industry

In the chemical industry, ammonium sulfate is used as a feedstock for the production of ammonium persulfate, used in the polymer industry. It's also a common ingredient in flame retardant compositions.

Food Additive

As a food additive, ammonium sulfate is used as an acidity regulator in flours and breads. It is listed under the E number E517.

Laboratory Use

In the laboratory, ammonium sulfate is used in the purification of proteins via precipitation. This process exploits the high solubility of ammonium sulfate in water, making it an effective tool for molecular biology.

Environmental Impact

Ammonium sulfate is considered safe for the environment with minimal toxicity. However, excessive use as a fertilizer can lead to soil acidification, which can decrease soil fertility and lead to water pollution.

Health Effects

Exposure to ammonium sulfate can cause irritation to the eyes, skin, and respiratory tract. Ingestion can lead to gastrointestinal disturbances such as nausea and vomiting. However, it is generally regarded as safe when used in food.

Regulation

Ammonium sulfate is regulated by various global entities depending on its use. In food, it is regulated by food safety authorities such as the Food and Drug Administration (FDA) in the United States. As a fertilizer, it is subject to agricultural regulations.

See Also

• Fertilizer
• Sulfuric acid
• Ammonia
• Protein purification