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T8 PM Measurement/ Estimation of Environmentally Relevant Physico-Chemical Properties
(ROT-1117-726142) Beyond Kow and vapor pressure.
Roth, C.1, 2, 3, Goss, K.-U.2, 3, Niederer, C.2, 3, Arp, H.-P.2, 3, Schwarzenbach, R.2, 3, 1 Harvard University, Boston, MA, USA2 Swiss Federal Institute for Environmental Science and Technology (EAWAG), Duebendorf, Switzerland3 Swiss Federal Institute of Technology (ETHZ), Zurich, Switzerland
ABSTRACT- Sorption of pollutants in various phase systems plays a key role for the transport and transformation in the environment. Many sorption processes between two specific phases have been examined, but only for a few compound classes. Results have often been evaluated with one-parameter linear free energy relationships (LFER) based on one compound descriptor, usually vapor pressure, water solubility, the octanol-water or the octanol-air partitioning coefficient. For many compounds, the experimental determination of these descriptors is error-prone and gives highly variable results. These LFERs also remain limited to the one compound class for which they were developed. Poly-parameter LFERs can overcome these shortcomings because they specifically consider the various types of interactions that govern each partition process: i.e. van-der-Waals and electron-donor/acceptor interactions. A comparison of both approaches shows that the poly-parameter LFERs have three important advantages: 1) for many compounds the required descriptors can be determined easier and with better precision, 2) the pp-LFERs successfully describe sorption for polar and non-polar compound classes alike and extrapolation to compound classes that have not been part of the calibration data set is much more reliable, 3) provides a method to describe and understand the variability of sorption properties in various compartments. The talk will illustrate these points with a large amount of experimental data, including a range of environmental compartments such as mineral and salt surfaces as well as various organic sorbents.
Key words: organic vapour partitioning, inverse gas chromatography, sorption model
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