PM07 Pollutant Chemistry Transport, Cycling and Fate
Exhibit Hall
8:00 AM - Monday
(PM080) Sorption and desorption behaviour of octylphenol in aquatic systems: role of colloids.
Zhou, J L 1, 1 University of Suseex, Brighton, East Sussex, UK
ABSTRACT- The sorption of octylphenol by sediment particles has been studied under simulated estuarine conditions. The sorption process was relatively rapid, reaching a sorption equilibrium within 28 h at a sediment concentration of 1 g l-1. With an increase in sediment concentration, it took longer for the sorption equilibrium to be reached. The sorption equilibrium can be adequately described by the linear partition model at low equilibrium aqueous concentrations. The sorption of octylphenol was enhanced in the presence of salts, due to the salting out effect. The sorption coefficient of octylphenol decreased with increasing sediment concentration, due to the presence of colloidal particles (i.e. 3rd phase) in suspension which were able to bind octylphenol. This third phase was quantified by measuring its dry weight, which was found to increase with increasing sediment concentration. In addition, the colloids were isolated by cross-flow ultrafiltration, which was then used for quantifying the interactions between colloidal particles and dissolved octylphenol. The results show that colloids are as effective as sediment particles in binding octylphenol. This, coupled with the abundance of colloids in the aquatic environment, suggest that colloids should have a significant role in the transport and cycling of organic pollutants. In addition, octylphenol previously bound to sediment particles can be desorbed, although the process is slower than sorption and not completely reversible.
Key words: Desorption, Sorption, Octylphenol, Colloids