M.Tech. (Chemistry) / This study investigated the functionalization of coke particles and their utilization for the preparation of coke-polymer composite. Looking at the possibility of using it for the removal of lead and chromium ions from their aqueous solutions. Due to various inorganic materials in coke, it was treated with acid to demineralize the ash content. The demineralized coke was further oxidized with hydrogen peroxide to add functional groups on its surface as well as in the bulk of coke particles before coating of the polymers. The composite preparation entails modifying the surface properties of coke with hydrophilic polymers like polyvinyl alcohol (PVA), poly ethylene glycol (PEG) and poly vinyl pyrrolidone (PVP) followed by the crosslinking to improve the interfacial interaction between the polymer and coke to make the synthesized composite stable in water. The structural composition of coke and modified coke was examined by FT-IR spectroscopy, X-ray diffraction, X-ray fluorescence, Raman Spectroscopy, thermal analysis and scanning electron microscopy combined with energy dispersive X-ray analysis. It was also observed that the modified coke samples have enhanced carbon reactivity which indicates that the non-carbon phases were removed by the treatment with acid. The adsorption studies for the removal of Pb (II) and Cr (III) ions from contaminated water was done in batch mode using variables such as pH, contact time and the initial concentration. The synthesized material was found to have better adsorption capacity as compared to raw coke. To understand the adsorption isotherm processes, Freundlich and Langmuir isotherms were applied. The monolayer adsorption capacity for the removal of lead ions was found to be 2.41 mg/g, 2.95 mg/g, 8.32 mg/g, 9.70 mg/g and 9.84 mg/g for raw coke, acid treated coke, PVA coated coke, PEG coated coke and PVP coated coke, respectively. The chromium monolayer adsorption capacity was found to be 9.48 mg/g, 9.94 mg/g, 35.84 mg/g, 32.79 mg/g and 34.13 mg/g for the same order of adsorbents mentioned for lead. Studies were carried out at the optimum pH of 6.0 for both the metal ions. The adsorption kinetic studies showed that both the metal ions followed pseudo second order rate equation and the adsorption equilibrium was attained in 60 minutes and 120 minutes for Pb (II) and Cr (III) ions, respectively.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:11615 |
| Date | 30 June 2014 |
| Creators | Mdlalose, Lindani Mbalenhle |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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