Hard work in the dark

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Hard work in the dark

 KANG KI-HEON
The author is an industry 1 team reporter of the JoongAng Ilbo.

There are many things that support modern society that are not so visible. They work in the dark, for the light. Notable examples are urea and ammonia. Urea, used as fertilizer material, was first discovered in 1773. In 1828, humans succeeded in making artificial urea, the first case of making an organic compound from inorganic compounds.

Urea, a colorless and odorless crystalline substance, is soluble in water. Mammals and amphibians excrete it as waste. Human urine is 95 percent water and 5 percent urea, potassium chloride, sulfate ions and phosphate ions.

Urea and ammonia are inseparable. Amino acids that make up proteins are broken down into water and carbon dioxide in the body to provide energy. In this process, nitrogen turns into ammonia. Ammonia, with its pungent odor, is dangerously toxic. The liver converts ammonia into less toxic urea for temporary storage. The liver combines carbon dioxide and ammonia to produce urea. Urea created in the liver is carried by the blood into the kidneys, stored in the bladder and then excreted in urine.

Urea is an essential component in fertilizer. Sixteen elements, including carbon and hydrogen, are necessary to grow crops, and nitrogen, phosphoric acid and potassium are referred to as the three elements of fertilizer because farmland often lacks them.

Urea, with the right combination of nitrogen, carbon and oxygen, is necessary to produce fertilizer. Urea can be mass-produced from ammonia extracted from coal. Ammonia, which consists of three hydrogen atoms and one nitrogen atom, is a substance from which hydrogen can be extracted to help lead the so-called hydrogen era.

I wonder if urea and ammonia have ever received so much attention. As China blocks its urea export, the market price of urea — the main component of diesel exhaust fluid (DEF) — rose to the level of organic olive oil, even surpassing that of gasoline. Since last month, DEF has been hard to buy even at a premium price. While the amount of urea excreted by the entire population through urine is not small, it cannot be directly turned into DEF. The same is true for urea for fertilizers and industries.

DEF is made by mixing purified urea with pure water. In the process, it passes through multiple filters to remove impurities. The DEF decomposes nitrogen oxides into nitrogen and water vapor. I was unaware of their hard work in the dark.

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