|
Zeolites are most useful commercially because of their unique crystal structure, which
allows them to act as molecular sieves – selectively sorting molecules based on particle sizes – that
adsorb gases and liquids. For example, zeolites are used in the current economy in pet litter,
animal feed, horticulture (fertilizers and soil additives), laundry detergent and water purification.
Zeolite-containing volcanic tuffs are also still mined to use as dimension stone, lightweight
aggregate and in cement. More than 40 natural zeolites have been identified during the past 200 years. Zeolites are
distinguished by differences in their chemical compositions and the size and arrangement of their
crystal structures. Clinoptilolite is the most commonly mined natural zeolite, followed by chabazite
and mordenite.
Current world production of synthetic zeolites is estimated to be about 1.4 million metric
tons per year. Almost 80 percent of synthetic zeolites are used in laundry detergent. More
recently, the U.S. military has been using synthetic zeolites as a hemostatic agent to promote
clotting of traumatic wounds. Additionally, copper- and silver-exchanged synthetic zeolites are
being used as antimicrobial agents in dust masks, plastic films and paints, and in antifouling paints
used to control barnacle growth on boats.
In this work zeolites synthetized by us from fly-ashes by hydrothermal method were
applied for removal of selected organic compounds from landfill leachate. A 6 types of zeolites
which were in different way activated were applied for our investigations. Depending on types of
examined compounds (BTEX, PAHs, PBDEs) results of removing varied from 38 to 99%.
This work was done in the frame of Applied Research Program (PBS-177630) – «Synthesis
and utilization of zeolite sorbents for removal of petroleum hydrocarbons»
|
