PT06 Contaminants-Receptor Interactions: New Challenges
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT098) Adsorption of Ionic Liquids onto Aquatic Sediments.
Beaulieu, Jake1, Tank, J1, Brennecke, J2, 1 University of Nortre Dame, Department of Biological Sciences, Notre Dame, IN, USA2 University of Nortre Dame, Department of Chemical Engineering, Notre Dame, IN, USA
ABSTRACT- Ionic liquids (ILs) are a new class of chemical compounds that are an attractive alternative to traditional solvents used in many industrial applications. Because they do not evaporate, ILs cannot be a source of fugitive emissions to the atmosphere. However, there is almost no knowledge of their potential environmental effects if they were to enter aquatic ecosystems via industrial effluents. Central to predicting the environmental effects of ILs in aquatic ecosystems is determining how ILs will be partitioned between the water column and sediments. To address this question we have conducted batch mixing experiments with 1-n-butyl-3-methylimidazolium chloride [bmim][Cl] and 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] in contact with three types of sediment: clean sand with no organic content, aquatic sediment with a 34% organic content, and aquatic sediment with a 65% organic content. After 20 hours neither IL had sorbed to sand, but both ILs sorbed to natural sediments within 15 minutes. IL sorption was highest with the 65% organic natural sediment (0.007 
mol IL/g sediment, Kd=8.4 L/kg). Only half as much IL sorbed to the 34% organic natural sediment (0.003 mol IL/g sediment, Kd=4.0 L/kg). These results indicate that sediments in aquatic ecosystems may serve as a sink for ILs with a [bmim] constituent.
Key words: Aquatic Sediments, Ionic Liquids