Abstract
The contamination of water by organic compounds has resulted in an escalation in research efforts to combat this problem. These organics can be harmful to human health and the environment in general, and they pose unique challenges to several industrial applications. Even when present at very low concentrations, they tend to bioaccumulate and interact with endocrine systems. However, due to the chemical nature of these compounds, current technologies are still challenged to effect their removal from water. Of currently used technologies, activated carbon and reverse osmosis can remove most of the organic pollutants but fail to remove them to very low concentrations (ng/L levels). Recent studies have explored the capabilities of nanoporous cyclodextrin (CD) polymers, a class of nanomaterials that show great potential to absorb organic contaminants from water.
The project reported in this dissertation was undertaken to further explore the efficacy of these polymers in order to assist industries and municipalities in their quest to solve the problem of water contamination by organic species. The ability of these polymers to remove selected organic contaminants from water at varying concentrations was studied. The investigated pollutants were chlorinated disinfection by-products (DBPs), taste and odour causing compounds (geosmin and 2-methylisoborneol) and humic acid, which was used to mimic natural organic matter (NOM). Water samples were pre-concentrated using solid phase extraction (SPE) and subsequently quantified by Gas Chromatography-Mass Spectrometry (GC/MS). The CD polymers demonstrated absolute efficiency at quenching organics at very low concentrations compared to granular activated carbon (GAC). The recyclability efficiency of the CD polymers was also investigated.
Most of the work was carried out using rapid small scale column tests (RSSCTs) that were designed in our laboratories. The general design of the study and pathway that was followed while conducting these experiments is shown in the flow diagram on the next page.
Dr. B.B. Mamba