Pollution Solutions: Natural Zeolites and Bentonites

Zeolites, an unusual group of minerals with a porous crystal structure, offer great potential for cost-effective solutions to a wide variety of environmental problems.  These uses are steadily expanding as research continues.

CH ZeoliteDue to their selectivity for large cations in solution, Clinoptilolite Zeolites (“clino”) provide an effective means for wastewater treatment plants to remove ammonium from solution.  Regeneration with a brine solution allows reuse of the clino and recovery of the ammonium for fertilizer production.

Zeolites can also absorb radionuclides from contaminated waters.  In addition to their usage at Three Mile Island for water decontamination, Zeolites have other uses in radioactive waste treatment/disposal.  Pilot scale testing of TMP zeolite, has been used recently to investigate the use of clino for sorbent barriers.  Clino barrier trenches are used for low-level waste to selectively absorb cesium, strontium and cobalt leached from the waste by infiltrating groundwater.  Other research includes testing to determine if clino can inhibit uptake of radioactive cesium by food crops on Bikini Atoll, the site of nuclear testing in the ‘40s and ‘50s.  If successful, this technique may also work to inhibit the uptake of heavy metals by plants.

XY ZeoliteThe newest environmental application of clino is for solidification/stabilization of hazardous waste.  PCP sludge from a wood treatment facility was successfully solidified for disposal in a hazardous waste site using TMP Zeolite. A successful in situ application combining zeolite, bentonite and cement has been used in a Superfund site to stabilize lead, PCP’s and creosote.

Research is ongoing for clino to remove heavy metals from contaminated industrial, agricultural and mine waters.  Clino exhibits an exceptionally strong affinity for lead, cadmium, silver and other metals.  It should prove extremely cost-effective compared to other materials commonly used for heavy metal sorption.  Zeolites can also absorb a wide variety of organic molecules and testing suggests they may effectively remove viral components.

Teague Mineral Products also provides high quality sodium bentonite for use as a soil sealant in sewage lagoons, hazardous waste sites, sanitary landfills and similar facilities which require impermeable barriers.  The high purity makes TMP bentonite very cost-effective since it generally requires less to achieve the desired permeability.