Browsing by Author "Rugayi, Bernard"

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    Application of natural adsorbents for removal of fluoride in water: a case of Gypsum and Bauxite
    (University of Dar es Salaam, 2019) Rugayi, Bernard
    The research was carried out to apply the natural adsorbent materials of bauxite and gypsum for DE fluoridation of portable water to meet the World Health Organization recommendation of fluoride contraption in water. The X-Ray diffraction and X-Ray Fluorescence tests were conducted to determine the structural components and chemical compositions of the adsorbents respectively. The X-Ray diffraction test indicated that the materials used in this research were bauxite with Al(OH)3 and gypsum with CaSO42H2O as major, components. The X-Ray Fluorescence showed that bauxite contained mainly Al2O3 (57.41%) while gypsum contained mainly SO3 (34.33%) and CaO (29.36%). The adsorbent materials were calcined at different temperatures of 200OC, 300OC and 400oC and the results showed that, the adsorbent materials calcined at 300oC performed best compared to those calcined at 200oC and 400oC for both bauxite and gypsum. The Langmuir and Freundlich model can be used to describe the sorption of both bauxite and gypsum indicating that the adsorbate forms a monomolecular layer on the surface of the adsorbent. The data for sorption kinetics fitted in pseudo-second order kinetics. The initial fluoride concentration in water was 15.21mg/L, with a dose of 30g/L and the final concentration was 0.36mg/L for calcined bauxite at 300oC while with the same initial fluoride concentration and dose for gypsum the final fluoride concentration was 6.05mg/L. with an adjusted Ph value of water to 4 with the same intial fluoride concentration and dose for both bauxite anf gypsum, the final fluoride concentration was 0.11mg/L and 3.9mg/L respectively.