Green, Caroline Elizabeth;
(2000)
An experimental and modelling investigation into the solid-phase extraction of pollutants from water.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The use of Solid-Phase Extraction (SPE) in the detection and monitoring of pollutants in water is reviewed. The main emphasis of this work is on the thermodynamic and kinetic processes involved in this extraction technique using octadecyl (C18) SPE disks. The equilibrium constant Keq, and the uptake rate constant kup, have been determined for the partitioning of twenty-one pollutants between water and a C18 SPE disk in a closed system utilising ultraviolet spectroscopy (UV) and gas chromatography - mass spectroscopy (GC-MS). The offloading rate constant koff, is obtained indirectly from Keq and kup. The twenty-one pollutants were chosen to represent a wide range of solute physic-chemical properties such as dipolarity/polarisability, hydrogen-bond acidity and basicity and size. The equilibrium and rate constants were regressed against the corresponding solute descriptors to produce Linear Free Energy Relationships (LFERs) for Keq, kup and koff taking on the general form: log SP=cr + r.R2 + s.p2H + a.Ea2H + b.Eb2H + v.Vx where log SP is log Keq, log kup or log koff, R2 is a solute excess molar refraction, p2H is the solute dipolarity/polarisability, Ea2H and Eb2H are the solute overall hydrogen-bond acidity and basicity and Vx is the McGowan characteristic volume of the solute. These LFERs provide a means for predicting log Keq, log kup and log koff for a given pollutant provided the solute descriptors are known. They also allow for some interesting chemical interpretation of the water-C18 disk system under investigation. It is shown how the work in this thesis is relevant to the partitioning of pollutants between water and a novel Aquatic Passive Sampler (APS), highlighting areas of applicability for the physical constants determined for the system in this work to the calculation of various parameters for alternative systems.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | An experimental and modelling investigation into the solid-phase extraction of pollutants from water |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| Keywords: | Pure sciences; Solid-Phase Extraction |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097535 |
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