UPV Theses and Dissertations
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Item Photodegradation of methylene blue in aqueous media using TIO2 -based heterogeneous photocatalysts under natural lightBernido, 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.Item Preparation and characterization of chitin-humic acid hybrid and chitin-humic acid hybrid hydrogel as absorbent for Cu(II)Balgos, Blyth Angela C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)Gelatinous chitin was functionalized with humic acid to produce a chitinhumic acid hybrid. The gelatinous chitin was protonated using HC1 and humic acid was deprotonated by using NaOH in separate containers. The protonated gelatinous chitin and the deprotonated humic acid were then mixed to form Hie chitin-humic acid hybrid. A portion of the chitin-humic acid hybrid was used to prepare the chitin-humic acid hydrogel. The chitin-humic acid hybrid hydrogel was then prepared using 1,2,3,4- butanetetracarboxylic dianhydride(BTCA) as crosslinker. The chitin-humic acid hybrid hydrogel was then characterized using FT-IR and swelling test. The degree of swelling of the chitin-humic acid hydrogel was found to be 38.10 ± 3.06. It can also be inferred from the results of the swelling test that the chitin-humic acid hybrid hydrogel has a low crosslink density. Characterization by FT-IR suggested successful immobilization for the hybrid and BTCA crosslinking for the hydrogel. The potential of chitin-humic acid hybrid and chitin-humic acid hybrid hydrogel to adsorb Cu(II) in a solution was then evaluated. The process was done by subjecting the chitin-humic acid hybrid to Cu(II) adsorption. The results for Cu(II) adsorption test was subjected to a Shapiro- Wilk test for normality and was determined to have normally distributed data. One- sample T-test was then used to compare the adsorption capacity of the hybrid and hydrogel. The mean % Cu(II) Removal of the chitin-humic acid hybrid and chitinhumic acid hybrid hydrogel were 41.36 ± 2.35% and 51.21 ± 1.32%, respectively. Results suggested that the chitin-humic acid hybrid hydrogel has significantly higher % Cu(II) Removal compared to the chitin-humic acid hybrid