Abstract
M.Sc.
This study was carried out to investigate the removal of organic and inorganic pollutants from water using phosphorylated and nonphosphorylated cyclodextrin polymers. The β-cyclodextrin was functionalized using various phosphorylating agents and the derivatives obtained were characterised with Fourier Transform-Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry. These derivatives were polymerized using hexamethylene diisocyanate (HMDI) as a cross-linking agent. The polymers were obtained in good yields ranging from 72 % to 93 %. They were characterised using Fourier Transform-Infrared (FT-IR), Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM)/EDXS), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to confirm the presence of phosphorus groups after polymerization. The removal of cadmium (II), chromium (III), trichlorophenol (TCP) and pentachlorophenol (PCP) was investigated in batch-mode experiments under varying conditions of pH, initial concentration and contact time. The concentration of heavy metal ions in water was determined using inductively-coupled plasma-optical emission spectroscopy (ICP-OES) and that of organic pollutants was determined using ultraviolet-visible (UV-Vis) spectroscopy. The polymers were found to adsorb up to chromium (III) better than cadmium (II) at pH 6.5. The maximum percentage removal of chromium (III) ranged between 83.9 % and 95 % whilst that of cadmium (II) ranged from 24.5 % to 39 %. There was no significant difference in the adsorption capacity of phosphorylated and phosphorus-free polymers in the removal of metals. However, phosphorylation improved the efficiency of the polymers in the removal of chlorophenols. The maximum percentage removal of TCP ranged from 17 % to 80.1 % whilst that of PCP ranged from 23 % to 77.2 %. The results obtained in this study demonstrate that the polymers are promising materials for the removal of Cr (III), TCP and PCP from water.