Browsing by Author "Madusanka, Y.V."

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    Synthesis of Graphite Oxide from Kahatagaha Vein Graphite Using A Localized Improved Hummers Method
    (Uva Wellassa University of Sri Lanka, 2013) Madusanka, Y.V.
    In modern world, materials, - regardless of their make, whether natural or synthetic — play a huge role. From all these materials, Graphite is taking a wide consideration of scientists as they are naturally occurring, cheap material with very interesting physical, chemical and mechanical properties. Graphte Oxide, (GO) has taken a considerable interest recently due to its applications in many fields. Many Studies have done for GO as an intermediate to the procedure of chemical synthesis of graphene and there are several other aspects of GO are still not have tested. Recent studies on Sri Lankan natural vein graphite have shown that it can be upgraded up to 99.97% carbon chemically, at low cost. (Amaraweera, et al., 2013). The aim of this study is to synthesize GO from chemically upgraded Kahatagaha vein graphite and characterize GO for surface modifications made by the oxidation of graphite. GO was synthesized using a localized version of improved Hummers method and then the characterization was done using FTIR spectroscopy, Conductivity measurements, Sheet resistance and XRD spectroscopy. There were several strong evidence for oxidation of graphite to GO and the proposed structure for GO (Klinowski, et al., 1998) can be supported with the findings of this study. However, the level of oxidation still should be studied further and a more economical procedure should be found to produce GO chemically for commercial purposes. Key Words: Graphite Oxide, Chemical Synthesis, Sri Lankan natural vein graphite.
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    Synthesis of Graphite Oxide from Kahatagaha Vein Graphite using a Localized Improved Hummers Method
    (Uva Wellassa University of Sri Lanka, 2013) Madusanka, Y.V.; Amaraweera, T.H.N.G.; Wijayasinghe, H.W.M.A.C.
    In modern world, materials, - regardless of their make, whether natural or synthetic – play a huge role. From all these materials, Graphite is taking a wide consideration of scientists as they are naturally occurring, cheap material with very interesting physical, chemical and mechanical properties. Within the range of applications of Graphite, Graphite Oxide (GO) and Graphene are more important as they are having many applications and very good potential in Nano scale materials and Nano Technology. GO has attracted much interest recently as a possible route for the large scale production and manipulation of Graphene, a material with extraordinary electrical properties. Sri Lanka has two major natural vein graphite deposits in Kahatagaha- Kolongaha and Bogala. Of the two Kahatagaha vein graphite has the highest purity that can be upgraded up to 99.97% Carbon by HCl leaching (Amaraweera et al, 2013). No researches and experiments have been conducted on Kahatagaha vein graphite which has been upgraded up to 99.97% Carbon in nano scale. The potential for value addition to Kahatagaha graphite has not yet been adequately explored. This study aims at synthesizing GO using a localized version of the Improved Hummers Method and characterization of GO to confirm the oxidation. Methodology Graphite sample, KNPG (Kahatagaha Needle-Platy Graphite) was first crushed using a hammer to obtain +10 mm chips and then the sample was milled in a disc mill for 15 minutes. The milled sample was sieved using a sieve shaker and <53 microns portion was taken for further treatments. 675 ml of 5% HCl was added to 50 g of graphite in 1000 ml beaker and it was vigorously stirred for 1.5 hours at 60 C. The solution was vacuum filtered and washed with distilled water (500 ml) and the same procedure was repeated once. Finally purified graphite was washed until the pH become neutral. KNPG achieved purity level of 99.97% Carbon. 9: 1 mixture of conc. H2SO4 (96% 360 ml) and conc. H3PO4 (85% 40 ml) were added to a mixture of 3 g of purified KNPG and 18 g of KMnO4. The mixture was stirred for 6 hours at 50 C. Then the solution was poured on to ice (200 ml) with 30% H 2O2 3 ml and then vacuum filtered through Fisherbrand filter paper. The brown product left on the filter paper was collected and washed with water (200 ml x 3) and left in a vacuum drier at 105 C for 2 hours. The hard black solid taken out from the vacuum drier was crushed using an agate mortar and pestle to obtain finer particles of 6.86 g of GO. A pellet for electrical conductivity measurements was made using 1g of GO and FTIR Spectrum for GO was taken. A tape was casted using GO for sheet resistance measurements and XRD spectrum was obtained for characterization of GO.