Organically modified bentonite clays, otherwise known as organoclays, have proven to be a useful tool in removing unwanted organic molecules from wastewater. The ability of organoclays to remove these organic molecules is due its structure. A chemical compound called quaternary ammonium cations, also known as quaternary amines, is added to the bentonite clay. The quaternary amines are surfactants that bind to the surface of the clay particle through an ion exchange process. The addition of these quaternary amines enables the clay to attract organic molecules and remove up to 30-50% of its dry weight in oil, grease, diesel, and other hydrocarbons in wastewater. This can be very useful in large applications. For example, a filter contains 100 lbs. of organoclay it should be able to absorb at least 30 pounds or about 4 gallons of oil.
The most common application of organoclay is the pre-treatment for water treatment systems with activated carbon filtration. Organoclay effectively removes the grease and oil from the wastewater before it enters the activated carbon. This pre-treatment allows the activated carbon to remove soluble organic compounds more efficiently. For systems that do not include organoclay as a pre-treatment application, the pores on the activated carbon will become clogged and compromise the service time and efficiency of the activated carbon. In conclusion, the combination of organoclay and activated carbon will reduce oil, grease, and other hydrocarbons to non-detectable levels in large-scale commercial applications.