Browsing by Author "Perera, M. D. H."

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    Catalytic activity of green synthesized Co3O4 and CuO nanoparticles in photoreduction of rhodamine B dye and transesterification of sunflower oil
    (Faculty of Science, University of Kelaniya Sri Lanka, 2024) Perera, M. D. H.; Abeysinghe, A. A. S. K.; Rathnayake, R. M. A. S.
    Recent advances in the field of nanotechnology have gained significant attention in developing ecofriendly methods for synthesizing nanoparticles (NPs), particularly metal oxide NPs. Present study explored the green synthesis of Co3O4 and CuO NPs using the extracts of Centella asiatica (gotukola) stems and Persea americana (avocado) seeds, respectively. This project was specifically aiming to minimize environmental impact while leveraging the natural properties of waste materials for effective NP production. UV-visible spectrometry, Fourier Transform Infrared (FTIR) spectrometry, X-ray Diffraction (XRD), and Scanning electron microscopy (SEM) analysis confirmed the successful NP formation and their characteristics. As regards photocatalytic properties, both Co3O4 and CuO NPs demonstrated significant effectiveness on degrading Rhodamine B (RhB) dye under direct solar irradiation. The optimized reaction conditions of each NP on dye degradation were studied by considering the maximum photodegradation obtained under tested conditions. With regards to Co3O4 NPs, pH of 8 with a 5mg catalytic load and a 5 ppm RhB dye concentration was considered as optimum conditions while achieving a 62% photodegradation efficiency which is 19% higher than the control. CuO NPs showed a maximum percentage photodegradation efficiency of approximately 55% under optimized conditions of 10 mg of catalytic load, pH of 8, and 5 ppm RhB concentration, which is 12% greater than that of the control. For both types of NPs, degradation performance was evaluated using fluorometry over a period of 240 minutes at 40-minute intervals. Furthermore, these NPs were studied as potential catalysts in the transesterification of sunflower oil to biodiesel. Optimization involved by varying oil-to-methanol ratio and the catalytic dose. The yield of biodiesel improved with an oil-tomethanol ratio of 1:3, showing a distinct layer separation. Further, experiments identified 15 mg of CuO NPs and 25 mg of Co3O4NPs as optimal catalytic loads, suggesting CuO NPs have comparatively higher efficiency in biodiesel production under relatively mild reaction conditions. During the transesterification process, two distinct layers were separated, and the bottom layer was identified as glycerol and the lighter top layer was confirmed to be biodiesel through an ignition test. Under the above-mentioned optimized conditions, CuO NPs showed better performance with a yield of ~67% (w/w%), compared to that of Co3O4 NPs which yielded ~59% (w/w%) of biodiesel. In conclusion, this study emphasizes NPs’ catalytic capabilities in both photocatalytic degradation of RhB and biodiesel production applications showcasing the significance of integrating natural resources and green chemistry principles in advancing nanotechnology for environmental remediation and renewable energy applications.