Gallagher, Louise
(2012)
Preparation and Characterisation of
Alginate Composite Beads and
Investigations into their Potential Use
in Environmental Applications.
PhD thesis, National University of Ireland Maynooth.
Abstract
The present research is concerned with the polymer sodium alginate, a naturally
occurring biocompatible and biodegradable polysaccharide.
The first objective was to prepare, characterise and monitor the release properties of
a urease inhibitor (NBPT) from different calcium alginate hydrogel beads. Four
bead types were chosen for this study, calcium alginate, charcoal-loaded and
bentonite-loaded calcium alginate, and polypyrrole-coated calcium alginate beads.
The surface morphology of the beads was investigated using SEM. The swelling
studies on the beads showed that the polypyrrole-coated calcium alginate beads
showed the lowest amount of swelling in all media tested. The stability of the NBPT
as a function of pH was investigated using NMR spectroscopy, which showed that
NBPT decomposes at acidic and highly basic pH values. The release of NBPT into
aqueous solutions was monitored using UV/Vis spectroscopy. Release was
uncontrolled if beads were agitated and was significantly slowed down when they
were not agitated. The bentonite-loaded and polypyrrole-coated calcium alginate
beads showed the most promising results for developing a controlled release system
for NBPT.
The second objective was to assess the ability of alginate beads, which contained
silver(I) and silver(0), to inactivate pathogenic microorganisms in a water treatment
process. The three different bead supports used were sodium alginate beads (Alg),
propylene glycol alginate composite beads (PGA) and alginate beads functionalised
with propyloctadecyldimethylammonium groups (TSA beads). Atomic absorption
spectroscopy was used to assess the amount of silver encapsulated in the beads.
Swelling studies in water indicate that the TSA beads were resistant to swelling. The
beads were studied for their ability to inhibit the growth or kill one strain of fungi
and five strains of bacteria. The TSA beads that contained silver(I) showed the
greatest antimicrobial activity against the six micro-organisms studied, making them
the most attractive polymer support, for use in materials for water disinfection.
| Item Type: |
Thesis
(PhD)
|
| Keywords: |
Preparation; Characterisation; Alginate Composite Beads;
Investigations; Potential Use;
Environmental Applications; |
| Academic Unit: |
Faculty of Science and Engineering > Chemistry |
| Item ID: |
15523 |
| Depositing User: |
IR eTheses
|
| Date Deposited: |
16 Feb 2022 14:41 |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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