Thesis-2004-Karounou.pdf (21.31 MB)
Removal of endocrine disruptors by activated carbons and Hypersol-Macronet hypercrosslinked polymeric adsorbents
thesis
posted on 2011-01-13, 10:14 authored by Eleni KarounouThe normal operation of the endocrine (hormonal) system can be disrupted by a
number of man-made and naturally-occurring chemicals, thereby affecting those
physiological processes that are under hormonal control. Such substances are
called endocrine disrupting compounds (EDCs). The endocrine disruption issue
has alarmed the environmental authorities since the substances involved can
hinder hormonal processes causing far-reaching effects on reproduction and
development in current and future human and wildlife generations. Effects on
some species of fish triggered worldwide concern and initiated a research scheme
which is being undertaken by various organisations e.g. United States
Environmental Protection Agency (USEPA), United Kingdom Environment
Agency (UKEA), Oslo and Paris Commission (OSPAR), Japan Environment
Agency (JEA) and World Wildlife Fund (WWF) in order to assess the effects
(present and potential), point of generation, levels of contamination and exposure
limits. The findings showed that most of the oestrogens are produced by humans
and animals and get discharged into river streams mainly through sewage
effluents. Fish in particular have been found to be affected the most even when the
oestrogenic levels in water are very low. The probability of future European legislation to eliminate hormonally active
compounds from wastewaters suggests that new and alternative methods should
be developed for their removal. In this work, the adsorption of 17ß-oestradiol (E2)
and 17a-ethinyl oestradiol (EE2) onto several granular activated carbons and
Hypersol-Macronet hypercrosslinked polymers was investigated by batch
experiments after a low level detection system had been developed using Gas
Chromatography Mass Spectrometry (GC/MS). Equilibrium experiments were carried out for all adsorbents to quantify the
sorption capacity for E2 and EE2. For better assessment of the sorbents
performance, their physical properties such as surface area, average pore diameter
and micropore volume and chemical structure were characterised by N2 adsorption
experiments, scanning electron microscopy (SEM), FTIR spectroscopy, elemental
analysis, sodium capacity determination, pH titration, proton binding curves and
zeta potential measurements. Adsorption isotherm data were fitted to the
Langmuir and Freundlich equations. Activated carbons were found to be
preferable to Hypersol-Macronet hypercrosslinked polymers for adsorption
purposes. The adsorption of oestrogens appears to be controlled by hydrophobic
interactions. Kinetic experiments were performed with different size ranges of adsorbents at
different concentrations and the results were analysed by a particle diffusion
model. It was found that concentration did not seem to influence the kinetics of
the oestrogen sorption whereas the particle size of the adsorbents influenced the
adsorption rate of both molecules. The particle diffusion model seemed to fit the
data collected for the adsorption rate of 17B-oestradiool onto the adsorbents but
gave a poor fit for most of the data collected for 17a-ethinyl oestradiol.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Publisher
© Eleni KarounouPublication date
2004Notes
Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.418395Language
- en