Research Symposium-2011

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Browsing Research Symposium-2011 by Subject "Chemical Engineering"

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    Development of a Detector to Determine Presence of Formalin in Fish
    (Uva Wellassa University of Sri Lanka, 2011) Lindamulla, I.; Wijesekara, K.B.; Wasala, M.P.
    Note: See the PDF Version Formalin is an aqueous solution of the chemical compound formaldehyde. Formalin is used as a disinfectant solution. Formalin is commonly used in aquariums to present the growth of parasites. In some cases formaldehyde is produced naturally by certain types of fish. Overuse of formalin causes many health risks for human. Many of these health issues may occur due to illegal use of the formalin. Recently some cases of illegal use of formalin were reported in many coastal areas in Sri Lanka. However, there is no rapid and economical method for formalin detection. Most of the detection methods require expensive and highTechnology apparatus, a large amount of samples, long sample preparation and detection time. Therefore, it is necessary to develop a simple, rapid and a convenient method avoiding the above mentioned disadvantages. The instrument designed is a convenient, rapid and a simplified method of detecting formalin iii fish and can be handled easily. It works at a high accuracy in a range between 100 ppm to 1000 ppm. The design is portable. Samples can be tested within a short period of time. The design is also cost effective and simple.
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    Kinetics Modelling of Partial Degradation of Carbofuran by Pyriye
    (Uva Wellassa University of Sri Lanka, 2011) Dhanasekara, S.A.K.M.; Walewela, N.; Jayarathna, L.; Nanyakkara, K.G.N.; Weerasooriya, R.
    Fenton Process is initiated by the formation of hydroxyl radical in accordance with the classical Fenton's reaction: Fe2+00 + H2024 OH + Fe3+0,4) If the product Fe" is reduced, the Fe2+ is regenerated for the next Fenton cycle; hence, Fe34 acts as an auto-catalyst. This reaction is also known to occur when Fe2+ is present in solid phase (Cohn et al., 2006; Kwan and Volker; 2003; Watts et al., 2003). The slow conversion of H202 -9 OH when magnetite, iron hydroxides, or pyrite are present is ascribed to a Fenton like mechanism (Cohn et al., 2006). In nature pyrite is the most abundant of metal sulfides. In Sri Lanka pyrite is an unwanted substrate in graphite industry. It is intimately associated with graphite by degrading the quality of the nation's graphite resource and it is confirmed that pyrite can be used as a starting material for purification of the water polluted with organic pollutants in both the presence and absence of light (Weerasooriya et al., 2006). When properly fabricated, pyrite based OH generation technology will hold a great promise in water treatment industry due to its simplicity, cost-effectiveness, and environmentally friendliness. Carbofuran (2,2-dimethy1-2,3-dihydro- I -benzofuran-7-y1 methylcarbamate) is a broad spectrum carbamate pesticide. Because of high water solubility of carbofuran (320 mg/liter at 25 °C) the risk of ingestion in to the human body is high Kidd and James (1991). Carbofuran, was selected for the present study with the aim of investigating its degradation in pyrite mediated aqueous environments under anaerobic conditions due to its wide use as an insecticide and nematicide in agricultural applications and high toxicity (Bachman et al., 1999).
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    Surface Modification of Activated Carbon to Treat Polluted Water Streams
    (Uva Wellassa University of Sri Lanka, 2011) Pathiraja, G.C.; Nanayakkara, K.G.N.
    NOTE: see the PDF version Water pollution due to the industrial applications, agro chemicals, etc. is a serious environmental problem which creates health, economical, and ecological impacts worldwide. The presence of toxic compounds, both organic and inorganic, in water streams creates significant threats to man and nature. Therefore, polluted water streams should be purified before releasing to the environment (Akhtar et al., 2006); (Massa et al., 2004). Adsorption is one of the most versatile and effective method, among other different methods. Adsorption is a natural process by which molecules of a dissolved compound collect on and adhere to the surface of an adsorbent solid. Activated carbon has a great potential for effectively removing contaminants from water by adsorption process due to its electrochemical surface properties. Most forms of activated carbon are non-polar in nature, so they have the greatest affinity for other non-polar substances. As a result, they are most effective in the removal of a variety of organic contaminants. However, activated carbons do not effectively remove trace metals, contaminants of high solubility or inorganic salts like nitrates. Hence, modifying the surface chemistry of activated carbon becomes an attractive route towards novel applications in enhancing the efficiency in water treatment (Chen et al., 2003). In this research, chemical treatment was used to modify the commercially available activated carbon and the modified material was characterized.