Browsing by Author "Attanayake, A.M.A.N.B."

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    Preliminary Investigations of Geochemical Characterization in Murunkan Clay Deposit, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Subasinghe, H.C.S.; Gayashini, K.Y.; Ratnayake, A.S.; Wijewardhana, D.T.U.; Pitawala, H.M.J.C.; Attanayake, A.M.A.N.B.
    Clay minerals are categorised into several groups as kaolin group, smectite group, illite group, chlorite group and 2:1 clays such as attapulgite and sepiolite. Over other clays, smectites are far more valuable due to their advanced application potential. Smectites exhibit excellent swell properties and the highest cation exchange capacity (CEC). Smectites can be used as adsorbents, filler material, drilling mud, excipients, and plasticisers. Montmorillonite is a layered alumino silicate with a higher specific surface area. It is also the most abundant of the smectite clays. The main objective of the current study is to identify spatial and temporal variations in geochemical characteristics of the Murunkan clay deposit. In this on-going project, two boreholes were drilled nearly 1 km distance each other in the Murunkan Basin. One borehole reached a depth of 6.5 feet while the other just passed a depth of 4.0 feet. Samples were cut into 5 inches of each core. Geochemical characteristics of the Murunkan clay deposit were evaluated for 15 clay samples and a Sigma Aldrich montmorillonite sample (reference material) using Xray fluorescence (XRF), X-ray diffraction (XRD) and Fourier Transform Infra-Red (FTIR) analyses. XRF results indicate ~57% SiO2, ~19% Na2O, ~10% Al2O3, ~5% Fe2O3, ~2% CaO, ~2% MgO, ~1.5% K2O, and ~1% TiO2. FTIR spectra of analysed clay samples show transmittance bands matching with the standard data of kaolinite and montmorillonite. Similarly, XRD analysis also suggests the occurrence of clay minerals such as montmorillonite, illite, kaolinite, chlorite, muscovite and cookeite. Quartz and feldspar can also be detected as the major impurities in the Murunkan clay samples. However, no considerable spatial and temporal geochemical variations can be observed in this deposit. Therefore, the Murunkan clay deposit can be identified as a prospective area for further exploration. The future research works would focus to demarcate the boundary of clay deposit and quantify the volumetric estimation. Besides, value additional potential such as purification and possible industrial applications would be examined. Keywords: Murunkan clay, Montmorillonite, Value addition potential
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    Purification of Kaolin in Meetiyagoda Kaolin Deposit, Sri Lanka by Bio Leaching for Removing Iron Oxide Impurities
    (Uva Wellassa University of Sri Lanka, 2020) Wijekoon, A.S.K.; Attanayake, A.M.A.N.B.; Henagamage, A.P.
    Meetiyagoda Kaolin has both iron and titanium impurities which cause deep coloration in it. Deep coloration in Meetiyagoda kaolin is the main barrier for most of the applications where the higher whiteness is necessary. This study was aimed to purify kaolin and enhance the whiteness properties by removing iron oxide impurities using microorganisms under bioleaching method. Bacteria and fungi were isolated from iron rich Meetiyagoda soil. Iron tolerated microorganisms were selected by inoculating the isolated microorganisms in nutrient media impregnated with different known concentrations of iron (200, 400, 600 and 900 ppm). Kaolin samples with three particle sizes (125-150, 63-125, and less than 63 microns) were separately treated with the screened microorganisms and the soluble iron concentration of the treated samples was measured under different time intervals using Atomic Absorption Spectroscopy. Out of screened bacteria and fungi types the most tolerated and the most suitable bacteria type and fungi type to leach iron impurities was investigated. Bio leaching ability was increased with the increasing particle size. The most convenient particle size was 125-150 microns. This biological treatment has shown one of the most effective processes for removing iron impurities and enhancing the whiteness properties of kaolin. The study concludes that the bioleaching method can be used for purification of kaolin in Meetiyagoda by using soil microorganisms and it can significantly improve the quality of kaolin from an industrial point of view. Keywords: Kaolin, Bacteria, Fungi, Bioleaching
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    Removal of Fluoride from Water using Zeolite
    (Uva Wellassa University of Sri Lanka, 2019-02) Ilayperuma, T.D.; Attanayake, A.M.A.N.B.
    The excess fluoride concentration in groundwater has become a major issue among many countries in the world. Also, in Sri Lanka several districts are affected with excess fluoride in groundwater. The main aim of this study was to introduce a cost effective and environmentally friendly fluoride removal method by using zeolite. A batch adsorption study was conducted at pH 7 and at room temperature by using test solutions containing 10 mg L-1 of initial fluoride concentration. The removal efficiency of adsorbent was studied by using different parameters like dose, contact time, stirring rate and initial fluoride concentration. The dose of adsorbent having the optimum fluoride removal efficiency was found to be 2.5 g. The optimum contact time, optimum stirring rate and the optimum initial fluoride concentration were found to be as 16 hours, 120 rpm and 8 mg L-1, respectively. Both the Langmuir and Freundlich adsorption isotherms fitted well for the fluoride adsorption on zeolite with the regression coefficient R2 of 0.96 and 0.97, respectively. Zeolite gave around 45% of fluoride removal efficiency and certain modifications to zeolite are needed to increase the efficiency.