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Item Development and characterization of a slow release fertilizer system using ammonium nitrate incorporated Gliricidia bark particles.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Premaratne, W.A.P.J.; Thisera, P.A.U.D.Best management practices for fertilizers in the application of plant nutrients should always aim to avoid a surplus of plant available nutrients in the soil. This will promote the efficient use of nutrients and minimize unfavorable effects on the environment. These conditions could be achieved by using slow release fertilizer systems. Experiments were conducted to determine the nitrogen (N), phosphorous (P) and potassium (K) contents in leaf, mid rib, root, bark and stem of gliricidia (Gliricidia sepium) plant and to develop a new slow release fertilizer system using ammonium nitrate (NH4NO3) incorporated gliricidia bark particles. Gliricidia plants were obtained from Rathmalagara estate, Madampe in Coconut Research Institute (CRI), Sri Lanka. New slow release fertilizer system was prepared from gliricidia bark particles (< 5 mm) after treating with a saturated solution of ammonium nitrate (NH4NO3). The morphology and physicochemical parameters of treated gliricidia bark particles were investigated. The release patterns of nitrogen from ammonium nitrate incorporated gliricidia bark particles (10 g) in a soil matrix (200 g) were investigated using columns with deionized water (pH 6.7). Parallel studies were carried out to evaluate the leaching patters of commercially available three nitrogen fertilizers sold in Sri Lanka in the soil matrix using the columns. Control reactions were carried out with ammonium nitrate in a soil matrix alone. Each experiment was carried in triplicate. Experimental results indicated that the level of nitrogen content in different parts of the gliricidia plants varied from 4599 mg kg-1 to 24381 mg kg-1. It was found that phosphorous content in gliricidia plant varied from 1367 mg kg-1 to 3143 mg kg-1. Potassium in different parts of the gliricidia plants varied from 140 mg kg-1 to 2600 mg kg-1. Therefore, gliricidia plant can potentially be used as a fertilizer source of nitrogen, phosphorous and potassium. After treating gliricidia bark particles with saturated ammonium nitrate, the total nitrogen content in gliricidia bark particles increased by more than six times with a maximum value of 67830 mg kg-1 after 6 hours. The initial nitrogen content in the bark was 10080 mg kg-1. According to the experimental results, within 24 hours more than 80% of the nitrogen was eluted from ammonium nitrate and commercially available fertilizers in the soil matrix given. However, only 24% of nitrogen was eluted from NH4NO3 incorporated gliricidia bark particles within 24 hours. After 15 days eluted nitrogen amount was recorded as only 43% from treated gliricidia bark particles. Therefore, it could be inferred that nitrogen was released from NH4NO3 impregnated gliricidia wood chips in a slow-release pattern. According to research data, it could be concluded that gliricidia bark particles have a great potential as a fertilizer carrier for the development of a nitrogen rich new slow release biomass fertilizer system.Item Engineered Nanomaterials from Mineral Resources: Application in Industry and Environment(Sri Lanka Association for the Advancement of Science, 2016) Premaratne, W.A.P.J.Item An investigation of the adsorption of dye (Bromothymol Blue) by Sri Lankan montmorillonite clay(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Premaratne, W.A.P.J.; Perera, V.M.Textile industries use dyes and pigments to color their products and thus produce wastewater containing organics with a strong color. However most of the synthetic dyes used in textile industry usually composed of aromatic structure, which makes them carcinogenic and mutagenic and non-biodegradable when discharged into waste streams. The removal of such colored agents from aqueous effluents is of significant environmental, technical and commercial importance. Clay has been accepted as one of the appropriate low cost adsorbents for removal of dyes from wastewater. Among the clay types montmorillonite has received considerable recognition because of its high adsorption capacity due to their lamellar structure which provides higher specific surface area and possibility to adsorb ions and other polar organic molecules on particle external site and in interlayer positions. In this study the adsorption of basic dye: Bromothymol blue (BTB) from aqueous solution by Sri Lankan montmorillonite was investigated. Montmorillonite clay used in this investigation was obtained from Murunkan clay deposit in Sri Lanka. Montmorillonite clay was examined for its performance as an adsorbent for the BTB removal. The effect of key operational parameters, such as contact time, initial dye concentration, adsorbent dosage, stirring rate and temperature were experimentally studied. Adsorption of BTB onto montmorillonite samples was studied by batch adsorption technique at 30±1 ºC using UV-Visible spectrophotometric method. For the BTB initial concentration of 70 ppm with the use of only 20 g/L of montmorillonite clay, the dye removal efficiency was found to be 63%. The equilibrium data was analyzed using Langmuir and Freundlich adsorption isotherms. Langmuir isotherm provided a better fit to the data. Characterization of clay before and after the adsorption was carried out by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) methods. XRD, FTIR and SEM data revealed that the dye did not penetrate in to the interlayer space of clay fully, but rather adsorbed on external surface by forming hydrogen bonding with the dye molecules creating a void free film on the clay surface. Experimental results confirmed that the Sri Lankan montmorillonite clay is an efficient adsorbent for basic dye removal. Therefore, Sri Lankan montmorillonite can be used as a promising low cost alternative adsorbent for removing basic dyes from dye wastewater.Item Extraction of copper from copper bearing sulfide ores (chalcopyrite) by oxidative chemical leaching(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Premaratne, W.A.P.J.; Dharmarathna, A.C.S.The extraction of copper from primary copper sulfide ores is much complicated and expensive. However, the successful metal extraction from natural mineral resources is very important, both environmentally and economically. The main objectives of this research work are to examine possible ways to increase the copper extraction from chalcopyrite (CuFeS2) using oxidative chemical leaching processes and to investigate oxidative leaching kinetics of chalcopyrite in sulfuric (H2SO4) acid medium. Chalcopyrite mineral sample was obtained from Geological Survey and Mines Bureau (GSMB) in Sri Lanka. Initial investigations characterized the chalcopyrite ore mineralogically and chemically. X-ray diffraction analysis of chalcopyrite ore reveled that only chalcopyrite (CuFeS2), azurite (Cu3(CO3)2(OH)2), pyrite (FeS2) and pyrrhotite (FeS) minerals were present. The copper content of the chalcopyrite ore sample was found to be 16.6% by weight according to the chemical analysis. The extraction of copper from chalcopyrite using hydrogen peroxide (H2O2), ferric sulphate (Fe2(SO4)3), potassium permanganate (KMnO4) and potassium dichromate (K2Cr2O7) oxidizing agents in acid solutions was studied using the 63-90 μm particle size fraction of chalcopyrite. The effect of temperature ranging from 30 ºC to 70 ºC, the effect of concentration of sulfuric acid ranging from 0.25 mol dm-3 to 5.0 mol dm-3 and the effect of pulp density ranging from 2% to 6% on the rate of dissolution of copper from chalcopyrite ore were also studied. The extraction rates are significantly influenced by the temperature and the concentration of the acid solutions. According to the oxidative chemical leaching results, the maximum extraction of copper was achieved with KMnO4 and then with K2Cr2O7, followed by H2O2 and Fe2(SO4)3. In this study maximum extraction of 70.2 % of copper was achieved at 0.1 mol dm-3 KMnO4 in 1.0 mol dm-3 H2SO4 acid. It was found that oxidizing agents improved the leaching kinetics of chalcopyrite in sulfuric acid medium saving both time and energy effectively and efficiently. A kinetic study showed that the dissolution of copper from chalcopyrite ore was controlled by chemical reaction process on the surface of particles. Based on the results obtained in this investigation, the apparent activation energy for the dissolution of copper using the Arrhenius expression was found to be 31.8 kJ mol-1.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.