What Is in Green Bags That Absorbs Ethylene Gas?

"Green bags" are a relatively new invention intended to help preserve produce. They do this by absorbing ethylene gas, which is given off by fruits and vegetables and speeds up the spoilage process.

What is in green bags?

• Zeolite is the ethylene-absorbing agent in green bags.

What is zeolite?

• Zeolites are a category of minerals that are known for their absorbent characteristics. They are aluminosilicates, meaning they are made up aluminum, silicon and oxygen.

Why are zeolites good for absorbing things?

• Zeolites are microporous and form regularly sized holes in their molecular structure. These pores in the zeolite green bags only let molecules of certain sizes in.

How do the pores trap ethylene gas?

• Because of the structure of zeolites, the pores formed in their crystalline structure have a negative charge. This allows them to attract and capture other ions, such as ethylene gas.

Are zeolites natural?

• Many zeolites are mined from natural deposits, but some are synthetically created. Zeolites are manufactured by companies such as Zeolyst and mined by companies such as St. Cloud Mining in New Mexico. Zeolites are widely used in the chemical, manufacturing and pharmaceutical industries.

Where are they found?

• Zeolites are found in places where volcanic ash and alkaline water have mixed in the past. Because of the Earth's volcanic history, zeolites are mined in North America, Europe, Asia and Australia.