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UPV Theses and Dissertations

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Committee Member: search.filters.committeemember.Cainglet, Rica P.

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    Photodegradation of methylene blue in aqueous media using TIO2 -based heterogeneous photocatalysts under natural light
    Bernido, Julidyn P. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    This study developed two heterogeneous TiO2-based photocatalysts: pure TiO2 and Fe-doped TiO2 (Fe-TiO2). Heterogeneous catalysts were prepared by coating TiO2 and Fe-TiO2 powder on glass beads. The photocatalytic activity of both heterogeneous photocatalysts were studied by photodegradation of methylene blue in aqueous solution under two pH conditions (6 and 9) and two ionic concentration conditions (0 and 38 ppt). The Fe-TiO2 powder contained minimal amount (2.245%) of Fe as expected. However, surface functionality and ultraviolet-visible (UV-Vis) profile of both TiO2 and Fe-TiO2 powder were very similar indicating that doping did not alter these properties. Between the two heterogeneous catalysts prepared, the amount of Fe-TiO2 catalyst coated on glass beads was lower compared to pure TiO2. The removal of methylene blue was significantly affected by ionic concentration which removal is higher at lower ionic concentration (0 ppt). Although it appeared that the removal of methylene blue was higher at pH 9, statistical analyses revealed that the effect was not significant. In addition, the removal of methylene blue by the two catalysts were significantly different. Heterogeneous photocatalyst based on pure TiO2 showed higher removal of methylene blue in all pH and ionic concentration. Moreover, no interactive effects between variables were observed. Lastly, the blank showed no significant difference on the removal of methylene blue with the heterogeneous photocatalysts which suggest that degradation by direct photolysis from sunlight could be the reason for this result.
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    Partial purification of pH indicator extracted from Rhoeo spathacea
    Apa, Junna T. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2009-04)
    pH test papers are still utilized nowadays despite the prevalence of pH meters, because it is more convenient to use in measuring the pH of a certain substance. The use of natural dye as a pH indicator can serve as a good substitute for an expensive commercial dye that most high schools cannot afford. The pH test papers were prepared by impregnation of 0.03% pure dye extracted from Rhoeo spathacea. TLC was performed to partially remove other plant dye components from the pH active ingredient. The color transition chart was then created at pH ranging from 1.0-13.0 at one unit interval using phosphate buffer. The color transition chart of pure dye extract was compared to the color transition chart of crude dye extract at different pH. Paper impregnated with 0.03% partially purified indicator dye extracted from Rhoeo spathacea showed color transitions from pink to red violet at pH 1.0-3.0; red violet to lavender at pH 3.0-4.0; lavender to blue at pH 4.0-7.0; blue to blue green at pH 7.0-8.0; blue green to green at pH 8.0-11.0; green to yellow green at pH 11.0-12.0; and yellow green to yellow at pH 12.0-13.0. Results also showed that the purified dye extract is a better pH indicator in comparison with the crude dye extract. Spectrophotometric determination of pKa of the indicator was unsuccessful due to the strong overlapping of the UV-Vis spectrum of the acidic and basic forms of the plant dye extract. Titration results showed that the plant indicator can serve as a substitute for the methyl red and phenolphthalein indicators for strong acid-strong base and weak acid-strong base titration, but not for weak acid-weak base titration.
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    Does a coral reef enhance the productivity of its surrounding waters?
    Peñafiel, Christen P. (University of the Philippines Visayas, 2019-06)
    Coral reefs have long been assumed and continually claimed to be origins of very high productivity, but how they attract organisms from and export nutrients to their neighboring waters remains largely unknown. Specifically, this study aimed at determining the space-time dynamics of nutrients and biomass redistribution around Hibotkan Rock Sanctuary (HRS), Banate, Iloilo, a sanctuary reef established by Municipal Fisheries Ordinance No. 12 covering an area of 25 ha. Twelve (12) sampling stations were established for space-time nutrient profiling, phytoplankton count, and supplementary measurements of water parameters, and four (4) stations for fish (biomass) visual survey. Results were analyzed using spatio-temporal plots and the Pearson correlation matrix (5% significant level). Nitrite was observed to be limiting, while nitrate was the most abundant in the waters of HRS. The predominant temporal variations of nutrients followed the flood tide (FT) and ebb tide (ET) cycles. In general, the tidal current direction appeared to control the redistribution of the nutrients (NO3-, NO2-, PO43-, and SiO44-). This study further revealed that stations of high nutrient concentration usually coincided with low levels of dissolved oxygen (DO). Species of fish observed were all indigenous and well-known inhabitants of the coral reefs. Furthermore, no other families of fishes (such as those of commercial value) were caught on record. Overall, there was no clear indication of import or export of living biomass in the HRS area. It can be inferred from the results that the fabled high productivity of coral reefs has no clear scientific basis; consequently, the Marine Protected Areas (MPAs) concept also appears to have no solid foundation.
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    Isolation of Hyaluronic acid from yellowfin tuna (Thunnus albacares) eyeball
    Sumogod, Angeleca A. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2019-06)
    Hyaluronic acid (HA) is commonly extracted from terrestrial and bacterial sources. However, due to the risk associated with either animal- and/or bacterial- derived contaminants and the laborious production processes that tend to compromise the quality of HA, research studies have recently shifted to the exploration of the presence of this polymer in marine resources and the enhancement of the protocols for HA production. Hence, this study focused on the isolation of HA from yellowfin tuna eyeballs. Results of the study showed that the optimum conditions for the isolation of HA from yellowfin tuna eyeballs are as follows: pretreatment of the raw material (acetone, formaldehyde and sodium acetate solution) prior to water extraction and incubation of the mixture for 24 h; tissue hydrolysis for a maximum of 6 h; a 3% CPC: 3M NaCl concentration for recovery and fractionation; and the use of 1:3 v/v supernatant: ethanol ratio for alcoholic precipitation. These results are expected to help maximize the benefits of the utilization of the tuna processing wastes in the country. Likewise, these findings may open a new opportunity for more cost-effective production of a valuable bioactive compound from marine source.