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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13

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Adviser: search.filters.advisor.Ortillo, Danilo O.AGROVOC Keyword: search.filters.agrovoc.humic acids

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    Optimization of parameters for the Fe-humic acid complex formation using cyclic voltammetry
    Bautista, Coleen M. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Humic acid extracted from an artesian well located at Sta. Barbara, Iloilo was used to generate an Fe-HA complex as a potential additive to bio floc systems to augment the essential mineral Fe. The humic acid obtained was black in color and had a powdery texture after oven-drying. The Fe-HA complex were prepared using Fe3+ ions at different pH values specifically at pH 8, 9 and 10. Formation of the complex was investigated using the cyclic voltammetry to determine the ideal conditions to maximize the binding of the metal ion. The results showed that there are two oxidation and reduction cycles which suggests that there are two species undergoing oxidation and reduction. It is possible that the free iron and the Fe in the complex are undergoing a redox cycle although the quinone group in the humic acid can also act as a redox center. Atomic Absorption Spectroscopy can help corroborate the amount of complex formed to help deduce the redox active center.
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    Optimization of parameters for the fe-humic acid complex formation using fluorescence spectroscopy
    Araniador, Glaicyl Dame Ann B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Humic acid was extracted from an artesian well located at Sta. Barbara, Iloilo. It was black in color and had a powdery texture after oven-drying. Humic acid samples were used to prepare complexes with Fe3+ ions to determine the ideal conditions to maximize the binding of the metal ion. Using the fluorescence data of the ligand as a comparative measure to confirm complex formation, varying concentration and pH conditions were used in preparing Fe-HA complexes. The excitation spectra of the different concentration ratios prepared showed that pH 6 favored the complex formation. The emission spectra showed that pH 6 exhibited high fluorescence signals. The EEMs of different concentration ratios at pH 6 showed that it is the optimal range for complex formation. In pH 8 and pH 10, no consistent pattern in their EEMs can be observed. This indicates that alkaline conditions, complex formation is not favored.