Browsing by Author "Senthilnathan, A."

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    In-situ Synthesis of Zinc Oxide Seeds on Thin Film of Mica as the Highly Reactive Photocatalyst Under UV-Light Irradiation
    (Uva Wellassa University of Sri Lanka, 2019) Senthilnathan, A.; Ekanayake, U.G.M.; Mantilaka, M.M.G.P.G.
    Structurally layered mica has attracted much attention of the mineralogists due to its unique structural properties. This study mainly concerns in developing the nano-seeds of Zinc oxide on thin film of mica (ZnO-mica) and the potential study of the photo-catalytic property under UV-light irradiation. The ZnO-mica was prepared by the In-situ growth of nanoparticles. 5 g of (0.5 cm × 0.5 cm) cut thin films of mica was added to the mixture of 600 µL, 50 mL of Cetyltrimethylammonium chloride (CTAC) and 2 mol dm-3, 50 mL of zinc nitrate hexahydrate. Then, Zn(OH)2 seeds were grown on the thin sheets of mica by adding 4 mol dm-3, 50 mL of NaOH solution with stirring for 24 hrs. The obtained product was then calcined at about 600 ℃. Finally, photo-catalytic property study was carried out in beakers containing 50 mL of Methylene Blue (MB) with various dose of (1.0, 3.0, 4.0 and 10.0 g) ZnO-mica. UV-Vis spectroscopy analysis was implemented with 30 min of time interval under the UV-light irradiation with initializing under dark condition for 30 min to 3.5 hrs. The synthesized final product was characterized by using the characterizing techniques such as X-ray powder diffraction and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy and thermo gravimetric analysis. The analytical data from the SEM reveal that the synthesized product with flower-like morphology having average particle length and width are 800 nm and 50 nm respectively. The crystallinity and the chemical analysis using XRD and FT-IR confirm the presence of ZnO on mica. The plot of percentage dye degradation versus time with increasing dosage under UV light indicates the rapid photo-catalytic dye degradation with increasing dosage of the photo-catalyst. The simple, flexible and novel method has been devised to develop the photo-catalyst under the UV-light irradiation.
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    Microbial Aided Leaching of Iron Contaminant from Eppawala Apatite to Produce an Effective Phosphate Fertilizer
    (Uva Wellassa University of Sri Lanka, 2017) Senthilnathan, A.
    Naturally Eppawala Rock Phosphate (ERP) contains a high concentration of iron bearing gangue mineral such as magnetite and, is suffering with the ineffective availability of phosphorous contents. Though, many of chemical and physical purification methods have been introduced, bio leaching has been identified as an effective and an ecofriendly technique for the removal of these impurities. Therefore, the present study aimed to remove the iron contaminants in ERP for the effective production of the fertilizer with high solubility. Microbial isolations were carried out using ERP soil samples obtained from Eppawala region, Sri Lanka. Pure bacterial cultures (B1, B2 and B3) were prepared on nutrient agar medium using the isolated microorganisms. ERP samples (5.000 g) with different particle sizes (500-150 pm, 150-125 pm and 125-63 pm) were mixed with 100 ml of pure bacterial broth cultures and incubated at 35 °C for 48 hours. Then, the cultures with a petite sample were kept at room temperature with continuous shaking until the AAS readings were obtained. Three replicates were maintained for each treatment. Approximately 10 ml of bacterial culture was taken out continuously from each microbial samples with three days intervals and AAS readings were obtained for the availability of ferric ion (Fe3±). Out of all bacterial cultures, the highest AAS reading (3.8233 mg/1) was obtained for the bacterial isolate B2. Further, ERP sample with (150-125 p.m) particle size showed the highest Fe3+ availability compared with the other particle sizes. Thus, it can be concluded that the bacterial isolate B2 has a positive effect on leaching iron contaminants of the ERP sample with (150-125 IA.m) particle size.
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    Microbial Aided Leaching of Iron Contaminant from Eppawala Apatite to Produce an Effective Phosphate Fertilizer
    (Uva Wellassa University of Sri Lanka, 2017) Senthilnathan, A.
    Naturally Eppawala Rock Phosphate (ERP) contains a high concentration of iron bearing gangue mineral such as magnetite and, is suffering with the ineffective availability of phosphorous contents. Though, many of chemical and physical purification methods have been introduced, bio leaching has been identified as an effective and an ecofriendly technique for the removal of these impurities. Therefore, the present study aimed to remove the iron contaminants in ERP for the effective production of the fertilizer with high solubility. Microbial isolations were carried out using ERP soil samples obtained from Eppawala region, Sri Lanka. Pure bacterial cultures (B 1, B2 and B3) were prepared on nutrient agar medium using the isolated microorganisms. ERP samples (5.000 g) with different particle sizes (500-150 um, 150-125 um and 125-63 gm) were mixed with 100 ml of pure bacterial broth cultures and incubated at 35 °C for 48 hours. Then, the cultures with a petite sample were kept at room temperature with continuous shaking until the AAS readings were obtained. Three replicates were maintained for each treatment. Approximately 10 ml of bacterial culture was taken out continuously from each microbial samples with three days intervals and AAS readings were obtained for the availability of ferric ion (Fe3+). Out of all bacterial cultures, the highest AAS reading (3.8233 mg/1) was obtained for the bacterial isolate B2. Further, ERP sample with (150-125 um) particle size showed the highest Fe3+ availability compared with the other particle sizes. Thus, it can be concluded that the bacterial isolate B2 has a positive effect on leaching iron contaminants of the ERP sample with (150-125 um) particle size.