The adsorption of saxitoxin to clays and sediments in fresh and saline waters

• Published in: Water research (Oxford) 2009-04, Vol.43 (7), p.1899-1904
• Main Authors: Burns, Justina M., Hall, Sherwood, Ferry, John L.
• Format: Article
• Language: English
• Subjects: Adsorption; algal blooms; Aluminum Silicates - chemistry; Applied sciences; Brackish; calcium; cation exchange capacity; clay; Cyanobacteria; estuarine sediments; Exact sciences and technology; Fresh Water - chemistry; Freshwater; Geologic Sediments - chemistry; Harmful algal bloom; Hydrogen-Ion Concentration; kaolin; Karenia brevis; Marine; montmorillonite; Other industrial wastes. Sewage sludge; Paralytic shellfish poison; Pollution; saline water; Saxitoxin - chemistry; saxitoxins; Seawater - chemistry; sediments; sodium; sorption isotherms; STX; Thermodynamics; Wastes; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2009.02.004

The adsorption of saxitoxin to Na- and Ca-montmorillonite, kaolin (crystalline and amorphous), kaolinite, Bread and Butter Creek sediment (an estuarine tidal creek), Gulf of Mexico sediment, and Santa Barbara Basin sediment in deionized water and 32‰ salinity simulated seawater (Instant Ocean™) is reported. Adsorption was partially reversible for all cases and best described using a Freundlich isotherm. The corresponding Freundlich constants ( K F) ranged from 8.83 × 10 3 μmol/kg to 6.76 × 10 4 μmol/kg for freshwater and 4.73 × 10 3 μmol/kg–1.11 × 10 4 μmol/kg for seawater. There is a positive linear correlation seen between the K F values and the cation-exchange capacity of the adsorbents. The release of saxitoxin from previously equilibrated adsorbents was determined in freshwater (0–18%) and seawater (4–53%).