Pollution Control and VOC Abatement

What is a VOC?

VOC stands for volatile organic compound. Volatile chemicals produce vapours at room temperature. Organic is a chemical containing carbon atoms. Volatile organic compounds include industrial chemicals, solvents, alcohols, and also petroleum products such as gasoline. VOCs combine with sunlight to form atmospheric ozone or smog.

What is Zeolite?

Zeolite is a naturally occurring mineral, in crystal form. Natural zeolite is made of hydrous aluminium silicates of sodium, calcium, potassium or barium ions.
Natural zeolite is hydrophilic (water loving) and readily adsorbs and desorbs water. More recently, synthetic zeolites have been developed for commercial applications. Over 70 types of synthetic zeolites have been created.

Hydrophobic zeolite is an inorganic, stable crystal with properties suited to adsorbing VOC’s. The zeolite's inert properties mean that it does not promote chemical reactions and will not even react with strong acids. It is also non-flammable to extreme temperatures.

Zeolite VOC Abatement Technology

The basic molecular structure of a zeolite is a tetrahedron or pyramid formed by silicon oxides (SiOn). The tetrahedron has one silicon atom in the center and oxygen at each of the corners. The tetrahedral zeolites are linked together by oxygen atoms. Linked zeolites form pores, the size of which are determined by how many zeolite molecules are linked together.

Depending of the number of linkages and which alkali ions are present in the crystal structure, several types of zeolites are formed, all with different pore sizes. The size of the pores also determines which VOCs can be adsorbed.

Munters Zeol uses a mixture of hydrophobic zeolites with different pore sizes. This mixture allows a wide range of organic solvents to be adsorbed. In fact, most commercially available solvents are adsorbed by these hydrophobic zeolites.

A VOC is attracted and held in the zeolite pore by a weak attractive force. This weak physical attractive force between chemically neutral compounds is known as the van der Waals force. The VOC will remain in the pore until it is heated, at which time the VOC will be released from the zeolite into the air.

When VOC laden air flows past zeolite molecules, the zeolite acts as a reverse filter or molecular sieve, capturing the compounds which are able to adsorb and allowing the compounds that are too large to flow past.