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Author: search.filters.author.Premaratne, W.A.P.J.

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    Lesson 06: Determination of pH value of a soil sample using a pH meter
    (Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Premaratne, W.A.P.J.
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    Lesson 05: Determination of water percentage of a soil sample at field capacity
    (Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Premaratne, W.A.P.J.
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    Lesson 04: Determination of soil density and its compaction or porosity
    (Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Premaratne, W.A.P.J.
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    Lesson 03: Determination of different fractions of soil by hydrometer test and textural triangle
    (Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Premaratne, W.A.P.J.
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    Lesson 02: Determination of water percentage in a soil sample by gravimetric analysis
    (Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Premaratne, W.A.P.J.
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    Microwave Assisted Dissolution of Sri Lankan Ilmenite: Extraction and Leaching Kinetics of Titanium and Iron Metals
    (University of Kelaniya, 2014) Premaratne, W.A.P.J.; Rowson, N.A.
    The kinetics of the leaching of titanium and iron from Sri Lankan ilmenite in a sulphuric acid medium heated by microwave energy is studied. The effects of the concentration of sulphuric acid, reaction temperature and particle size on the kinetics of dissolution of ilmenite are investigated. Results show that both the acid concentration and the temperature have significant effects on the rate of dissolutions of titanium and iron from ilmenite. The dissolution of both titanium and iron from ilmenite was controlled by a chemical reaction on the surface of ilmenite particles. Maximum extractions of 74.2 (±1.1) % of titanium and 71.3 (±0.8) % of iron from the ilmenite ore were achieved using a microwave leaching system of 600 W, 2.45 GHz. Experimental results further showed that the apparent activation energies for the dissolution of titanium and iron were 137 kJ mol-1 and 117.1 kJ mol-1 respectively. Therefore, microwave energy has a potential for the speedy and efficient leaching of ilmenite and in a commercial context it can be used as a more economical and environmental friendly process. The results of the mineralogical and chemical analysis studies for the ilmenite ore indicated that both ilmenite (FeTiO3) and pseudorutile (Fe2Ti3O9) minerals were present with a grade of 37.9% titanium.
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    Synthesis of Nanosilica from Paddy Husk Ash and Their Surface Functionalization
    (University of Kelaniya, 2013) Premaratne, W.A.P.J.; Priyadarshana, W.M.G.I.; Gunawardena, S.H.P.; de Alwis, A.A.P.
    Nanosilica was synthesized by a chemical precipitation process from paddy husk ash (PHA) efficiently and effectively. Surface functionalization of the silica nanoparticles was carried out with oleic acid (C18H34O2). Scanning electron micrographs (SEM) data showed that the nanosilica particle size was in the range of 50-70 nm and they were in the agglomerate form. X-ray diffraction (XRD) analysis data revealed that synthesized nanosilica was in amorphous form showing a strong broad peak at 22.14o (2). Fourier transform infrared spectroscopy (FT-IR) data supported the presence of hydrogen bonded silanol group and siloxane groups in nanosilica. Surface functionalized nanosilica with oleic acid was characterized using thermogravimetric analysis (TGA) and FT-IR methods. FT-IR experimental data showed that the modified nanosilica formed the ester bonding between silanol group in nanosilica and the carboxylic group of oleic acid with a successful functionalization.