Perchlorate Sorption by Natural Zeolite Modified with Cationic Polymers

Cationic polymers are widely used in water and wastewater treatment industry as flocculants and coagulant aids to control suspended solid levels. Many cationic polymers, those with quaternary amines in particular, are toxic to aquatic organisms at very low concentrations (< 1 mg/L). Natural zeolite (clinoptiolite) was used as an inexpensive sorbent material to remove cationic polymers from contaminated waters. Our preliminary batch tests indicated that the 8-14 mesh zeolite was able to sorb about 200 meq/kg of polydiallydimethylammonium chloride (poly-DADMAC), a cationic polymer commonly used in wastewater treatment. The resultant material (zeolite saturated with poly-DADMAC) was able to remove up to 20 mmol/kg of perchlorate, an endocrine disruptor found in surface and ground waters of many parts of the US. Column tests are currently underway to examine the sorption of several different types of cationic polymers by the zeolite, the stability of the sorbed polymers, and the sorption of perchlorate and other anions by the polymer-modified zeolite.