Water is an important resource. It is used for domestic, industrial, agricultural and recreational purposes. The quality of water is, however, significantly deteriorating due to the accumulation of organic species in aqueous system. Domestic, industrial and commercial activities comprise the biggest source of organic pollutants in municipal water. The increase of water pollution by these organics has led to the development of several water purification measures. Among others, water treatment technologies that are in place consist of ion exchange, activated carbon adsorption, reverse osmosis, molecular sieves and zeolites. However, none of these techniques have been reported to remove organic pollutants to parts-per-billion (ppb) or microgram-per-litre (ìg/L) levels. Recently, it has been reported that cyclodextrin nanoporous polymers are capable of absorbing these pollutants from water to such desirable levels. Cyclodextrins (CDs), basically starch derivatives, are cyclic oligomers consisting of glucopyranosyl units linked together through á-1,4-glycosidic linkages. They behave as molecular hosts capable of interacting with a range of guest molecules in a noncovalent manner within their cylindrical hydrophobic cavities. These interactions are a basis for the inclusion of various organic species. However, the high solubility of cyclodextrins in aqueous medium limits their application in the removal of organic pollutants from water. To make them insoluble, they are converted into highly cross-linked polymers. This is achieved by polymerizing the cyclodextrins with suitable difunctional linkers. In this project, a wide variety of monofunctionalized CDs have been effectively prepared using efficient modification strategies and successfully characterized by Infra-red (IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. From these monofunctionalized CDs and corresponding linkers, insoluble nanoporous polymers with different physical properties were synthesized (Scheme 1). / Dr. B.B. Mamba
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:1730 |
| Date | 15 May 2008 |
| Creators | Nxumalo, Edward Ndumiso |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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