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Undergraduate Theses

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Committee Chair: search.filters.chair.Pahila, Ida G.SDG: search.filters.sdg.SDG 6 - Clean water and sanitation

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    Moss (Brachythecium sp.) and a filamentous green algae (Oedogonium sp.) as bunker oil sorbents
    Bautista, 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.
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    Bioaccumulation of cadmium, copper and lead by Hydrilla (Hydrilla vericillata)
    Baniago, Arjay C. (Division of Pysical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)
    Bioaccumulation of cadmium, copper, and lead by Hydrilla (Hydrilla verticillata) were tested to 5 different initial concentrations. The water contaminant sample was composed of mixed cadmium, copper and lead metals supplied as nitrate salts. These were analyzed for the decrease in concentrations at 24-hour intervals for 5 days using the SpectrAA 55B Atomic Absorption Spectrometer. Plants exposed only for 5 days were digested and analyzed. The plant growth was normal at lower concentrations and showed higher removal efficiency. H. verticillata showed maximum removal percentage on the 5th day of exposure at 5 mg L-1 for cadmium (90.47%) and copper (95.20%) but for lead was on the 1st day (96.74%). The order of metal ion removal and the actual uptake for the three metals by H. verticillata is Pb>Cu>Cd, but at lower concentration, cadmium was absorbed more than copper. The copper and lead uptakes by H. verticillata are superior as compared to other aquatic plants uptakes. Lead uptake at higher concentrations might be due to physicochemical adsorption of the metal to the plant components and not on metabolism-mediated uptake, because plant condition does not have an adverse effect on the uptake