UPV Theses and Dissertations
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Item The adsorption capacity of silica gel and rice hull ash on phenol and anilineBulatao, Ben Fermin P. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)Chemical waste has been a problem here in the University of the Philippines Visayas, Miagao, Iloilo. Various methods of removal have been utilized. Extraction of silica gel from rice hull and rice hull ash was used to remove organic compounds (phenol and aniline). In this study, silica gel and rice hull ash adsorption on phenol and aniline were investigated with varying contact time and initial concentration. Silica gel reaches its optimum adsorption of both phenol and aniline at 60 minutes contact time. Silica gel was the basis for rice hull ash’s contact time because rice hull ash is 90% by weight silica gel.. Silica gel-phenol system decreases it adsorption capacity as the initial concentration is increased from 25 ppm to 100 ppm. Rice hull ash- phenol system, on the other hand, shows that the adsorption capacity increases as the initial concentration is increased. Both on silica gel-aniline system and rice hull ash- aniline system have increasing adsorption as initial concentration is increased. As the contact time is increased, adsorption increases only until it reaches its optimum adsorption which is 60 minutes contact time where saturation is reached. Increasing initial concentration however has different effect on adsorption on all system explained by the adsorption isotherms. The isotherms show that phenol has the fastest rate to form a monolayer (K and Q°) with the greatest binding strength (b) on silica gel. It is also observed that phenol and aniline formed a monolayer (1/n) on the surface of the silica gel and rice hull ash.Item Antifungal activities of alginate films incorporated with lemon grass (Cymbopogon citratus) essential oil on sliced breadBronzal, Lucile A. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)The accumulation of non-degradable and non-recyclable waste materials leads researches to venture on biopolymer films which have been regarded as the promising green substitutes of non-biodegradable plastic materials. However, food products can be subjected to contamination by bacteria and fungi. The addition of plant derived essential oil can control microbial contamination of foods by reducing the growth rate of target microorganisms or by inactivating microorganisms by direct or indirect contact. Incorporating antimicrobial compounds into films provides a different way to improve the safety of ready-to-eat foods. In this study, the efficiency of synthesized alginate films incorporated with lemon grass essential oil (LGEO) for antifungal activity on white bread was evaluated. Two sets of film were prepared the (1) LGEO - Ethanol incorporated films and (2) LGEO — β-cyclodextrin inclusion complex films via solution casting method. Furthermore, the FTIR analysis of the generated films was also assessed to identify the functional groups present in the film that facilitates its antifungal property. Experimental results showed that LGEO enhanced the antifungal properties in the films and significantly slowed down the propagation of fungi on white sliced bread. After two weeks of storage, all bread samples packed with various film samples showed fungal growth. It was found out that citral is the main component of essential oil which contributes to the inhibition of fungal growth. The incorporation of LGEO in the film decreased the O-H peak absorbance while the inclusion complex in the film increases the O-H peak absorbance and broad O-H peaks were also obtained.Item Extraction of humic substances from vermicompost and application as component matrix for slow-release fertilizersBoloron, Nina Loren R. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Humic acid was extracted from vermicomposts (hereafter referred as VCHAs) by alkali/acid fractionation and their concentration were determined to be 54.79 (± 0.25) g HS/kg vermicompost in average. The extracted humic substances from vermicomposts were also determined to contain an average K+ of 0.0671 (± 0.0053) g K/kg vermicompost. The Fourier transform infrared spectra of crude VCHSs show similar spectral features with humic acids extracted from vermicomposted materials. The VCHSs were complex with K nutrient and encapsulated in cross-linked Ca-alginate to form vermicompost humic substance — potassium slow-release fertilizer bead (VCHS-K SRF). The synthesized VCHS-K SRF were subjected to total nutrient analysis, swelling kinetics, and slow release test to evaluate the role of nutrient compositions on its capability and capacity as slow- release fertilizer. Results for total nutrient analysis show that with an increase in nutrient loading, encapsulation efficiency is low and nutrient concentration is low. These findings imply that at neutral pH of HS solution, binding sites are saturated with Na+, therefore with having the same affinity as K+ , minimal ion exchange took place and it became difficult for K+ to bind to the HS complex. It also suggests that the amount of polymer coating and the degree of crosslinking were not sufficient to hold all nutrients. Discrepancies on the amount of released K+ was also observed on the release profile as a product of errors on acid digestion and matrix effect, this lead to elevated amounts of release by the VCHS-K SRF. The result of the release behavior profile of VCHS-K SRF shows that with an increase in enriched nutrient load, the release rate is faster. The results on the release profile of the VCHS-K SRF exhibited a parabolic and burst release. This finding in relation to the observed fluctuations on the absorbency pattern suggests that internal pressure build-up on the polymer matrix caused abrasions on the surface of the polymer coating resulting to the instantaneous release of nutrient and absorbed water. Overall, the VCHS-K SRF cannot be classified as a slow-release fertilizer. The present findings suggest the need for further improvement on the study of VCHS-K SRF from vermicompost.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 Moss (Brachythecium sp.) and a filamentous green algae (Oedogonium sp.) as bunker oil sorbentsBautista, Norwell Brian C. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)Oil spills are very catastrophic and very destructive events. One way of controlling the dispersion of oil from these spills is by the use of sorbents. The procurement of commercial sorbents can be very costly. Thus, this study analyzed and evaluated the efficiency and effectivity of moss (Brachythecium sp.) and a green filamentous algae Oedogonium sp. as substitutes for commercial sorbents. Brachythecium sp. can grow in any moisture—rich environment and Oedogonium sp. algae grow freely in fish ponds and in any body of stagnant, oxygen-poor water. Thus, both samples are very abundant in the environment. Sorption capacity results showed that the moss Brachythecium sp. and the algae Oedogonium sp. can sorb five times and seven times its weight, respectively. In comparison, Peat Sorb, a commercial sorbent, was recorded to sorb 15 times its weight (Emedco, 2007). The minimum sorption capacity of the moss and algae samples was recorded to be approximately equal to their weight. The adsorption isotherms of both samples follow the Langmuir plot for monolayer adsorption. In the hexane capillary rise experiment, hexane rose significantly in ground moss (72.25 mm in 7 min.) and unground moss (64.80 mm in 7 min.) compared with unground algae (23.52 mm in 7 min.) and (20.70 mm in 7 min.), indicating that moss is more hydrophobic. In water, capillary rise, on the other hand, unground algae is a better medium (5.76 mm in 4 min) compared to the rest (ground algae - 4 mm, unground moss - 5.29 mm, and ground moss — 4.11 mm, all in 4 min.). Results also revealed that the moss Brachythecium sp. and the algae Oedogonium sp. expressed hydrophobic characters in the hexane-water system by remaining in the hexane layer after agitation. The moisture content of the algae (14.85%) is twice that of moss (7.94%). This gives the moss an advantage in oil sorption. The lipid contents of algae (15.58%) and moss (11.47%) do not comprise the majority of their biomass, but the lipids aid in increasing the samples’ affinity for non-polar substances. The samples may not sorb as effectively as the commercial sorbents, but they are abundant in the environment, thus, a cheaper alternative. Like Peat Sorb, which was processed from the biomass of Sphagnum sp. moss, the samples may undergo the same process that increases the hydrophobicity several-fold and gives oil-biodegradation capabilities.Item Antifungal activities of lemongrass (Cymbopogon citratus) essential oil -B-cyclodextrin inclusion complex incorporated in commercial fish feedsBaure, Jiaren G. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)During the wet season in the Philippines, fish feeds can be contaminated with mycotoxins, affecting fish production. The addition of essential oil (EO) is one of the ways to prevent this, but it is prone to physical and chemical reactions. Thus, this study aims to encapsulate lemongrass essential oil (LGEO) in B-cyclodextrin (B-CD) to produce an inclusion complex (IC) that can be used as an additive in commercial tilapia feeds to prevent or minimize fungal contamination. The inclusion complex was made using the co-precipitation method and was characterized by Fourier Transform Infrared (FTIR) Spectroscopy. The spectrum was similar to that of citral, a major component of lemongrass essential oil that is responsible for inhibiting fungi. The antifungal activities of pure and encapsulated LGEO at varying concentrations against Aspergillus species were carried out by the Agar Well Diffusion assay. Results showed that A. flavus was more susceptible in LGEO and IC compared with A. fumigatus. The tested concentration of EO could inhibit both fungi. However, it would take 50% IC to effectively inhibit the growth of both fungi. The stability of the inclusion complex in commercial fish feeds was also evaluated. The feeds were stored in an area with the appropriate conditions that could promote the growth of molds, such as temperature (>27°C), moisture levels (14%), and relative humidity levels (>70%). The results showed that the encapsulated LGEO was effective in extending the shelf life of the feeds and was best observed at a concentration of 5 g kg-1 IC. The oil remained active for nine days, wherein about 10- 40% of the feeds with 5 g kg-1 IC were covered with molds. On the other hand, about 70-100% of the surface of the feeds with essential oil was contaminated with molds after nine days, which indicated that encapsulation of EO was needed to maintain its effectiveness as an antifungal agent.Item Vulnerability and adaptation to sea level rise of coastal communities in San Jose, Antique an application of contingent valuation methodBaltazar, Christina C.; Mojica, Mariane Daiseree P. (Division of Social Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)San Jose, Antique is a coastal municipality that is already experiencing manifestations of sea level rise, most visibly evident in coastal erosion, increased frequency of flooding, and higher storm surges. Sea level rise is a problem that affects the societal, economic, and environmental condition of coastal communities. It poses threats to life, property, and livelihood thus making these coastal communities vulnerable. To address their vulnerability, planned adaptation is the most practical option. Employing contingent valuation method, this study aims to determine the willingness-to-pay of coastal communities for a planned adaptation program that will address sea level rise. This study also aims to identify the adaptation measures that coastal communities of San Jose, Antique currently employ. Results show that the adaptation measures currently employed by the coastal communities of San Jose are autonomous, such as putting up sandbags, constructing bamboo corrals, and evacuating. These adaptation measures are stopgap solutions, which offer short-term protection only. It was seen, moreover, that overall, participants are willing to pay for a planned adaptation program. This suggests that funds may be raised for a planned adaptation program, which may be done through mobilizing the willingness-to-pay of the people. Measures to tap this potential should be explored by various groups, especially the local government unit of San Jose, Antique.Item Treatment of Vibrio harveyi-infected Penaeus monodon using Alibutbut (Tabernaemontana pandacaqui Poir.) plant powderBacaling, Marivic T. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2005-04)The cytotoxicity test of crude methanolic leaf extract using Brine Shrimp Lethality Assay revealed that Alibutbut (Tabernaemontana pandacaqui Poir.) is safe to use in treating vibrio-infected penaeid shrimps. The effectiveness of the alibutbut powder against vibriosis was examined through the determination of the post-larvae 20 (PL 20) penaeid shrimp mortality and the water microbial assay after 48 hours. Percent penaied shrimp mortality (0-6.67%) and microbial count (2.91 x 10^4- 3.26 x 104 cfu/mL) of the plant treatments were significantly lower compared to the negative control (no treatment) that exhibited 50% penaeid shrimp mortality and a microbial count greater than 6.00 x 10^4 cfu/mL. The results of the experiment showed that Alibutbut plant powder is indeed effective in controlling Vibrio harveyi bacteria.Item Cytotoxicity and anti-vibriotic activity of Noni as an ethnobotanicalArrojo, Marley C. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2005-12)The crude methanolic extract of Acacia, Alibutbut, Bayabas, Biab, Botolan, Bulobitu-un, Buyo, Kamunsil, Kasla, Kayos, Langka-langka, Noni, Pasaw, Sampaguita, Tabong, Talisay, Yellow bell, were bioassayed for their cytotoxicity using brine shrimp nauplii assay. Among the plant extracts, Noni gave the highest LCso equal to 943.329 pg/mL. Noni was the least toxic among the plants tested and its crude methanolic extract was found to have activity against V. harveyi with an anti-vibriotic index of 0.256. Sequential extraction using solvents with increasing polarity gave fractions that exhibited anti-vibriotic property but the more polar ethyl acetate fraction gave the highest anti-vibriotic index of 0.513. It appears that the anti-vibrio constituent is polar. Using VLC, the ethyl acetate fraction was further separated into eighteen fractions which were in turn pooled into five fractions, Fa, Fb, Fc, Fd, and Fe based on their TLC profile. Anti-vibriotic activity of each fraction was determined. Fraction Fa has the highest anti-vibriotic index (0.192) but this is much lower than 0.513. There must be some synergy among the polar constituents that exhibited a higher anti-vibriotic index in the ethyl acetate fraction compared to fraction Fa. Based on several color reactions, ethyl acetate fraction may contain any of the following plant metabolites such as tannins, saponins, phenolic groups, conjugated double bonds, flavonoids, sterols, terpenes, except alkaloids.Item Heavy metal concentrations in sediments from Batan Bay and its tributariesAndrada, Mary Royce D. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2014-04)The concentration of three heavy metals (Cd, Pb, Cu) in sediments from Batan Bay and its tributaries were determined in order to assess the degree of contamination of sediments in the said area. The samples were digested following the Method 3050B of US Environmental Protection Program (EPA, 1996). The heavy metal concentrations were determined using Flame Atomic Absorption Spectrometer (FAAS). Results show that the heavy metal concentrations ranged from n.d. - 2.57 mg/kg dry weight (dw) for Cd; 16.44-143.02 mg/kg dw for Cu; and 3.18-28.53 mg/kg dw for Pb. Sediment sample collected from BTN #10 has the highest Cd concentration while sediment sample collected from BTN 052 which is a rice field in Batan, Aklan registered the highest Pb and Cu concentrations. Three sediment quality guidelines (National Oceanic and Atmospheric Administration, Canadian Sediment Quality Guideline and Hong Kong Sediment Quality Guideline) were employed to assess the metal contamination in sediments. The concentrations of Cd and Pb in all sites did not exceed the maximum permissible limits set by the three guidelines. As for Cu, BTN 052 exceeded the Upper Chemical Exceedance Level set by Hong Kong SQG. Correlation analysis showed that there is a significant correlation (p <0.01) between Pb and Cu indicating possible similar source input. Special attention must be given to BTN 052 since the levels of the studied heavy metals are high in this area. The results can be used as basis for the pollution level of sediments from Batan Bay and its tributaries. Special consideration should be given to BTN 052 since all of the test metals are significantly high in this area. It is also suggested to in identify the primary sources of metal contamination in this area.