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AGROVOC Keyword: search.filters.agrovoc.humic acidsDegree: search.filters.degree.Bachelor of Science in Chemistry

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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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    Antioxidant property, total phenolics, manganese and iron content of humic acid obtained from Sta. Barbara, Iloilo artesian well water
    Baltazar, Lenmark Anthony M. (Division of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    The town of Santa Barbara in Iloilo is famous for its reddish browncolored well water due to the presence of humic acid which makes up most of the water’s natural organic matter content. Because the well water is used by the local townsfolk for drinking and other domestic activities, it is imperative that a study must be made to assess its potential health benefits and risks. In this study, the DPPH radical scavenging activity of the extracted humic acid was investigated. It was determined that the sample contains antioxidants capable of reducing DPPH with an IC5o of 51.552± 0.652 ppm. Prussian Blue Assay for total phenolic content also showed that a 76.5 ppm humic acid sample has 14.169 ± 1.151 ppm in GAE. Flame-AAS analysis showed that the humic acid sample contains iron (0.8376 ± 0.0581 ppm). The manganese content of the sample was below the detection limit of the instrument. The results suggest that the humic acid extracted from the well water contains potential antioxidants which can be exploited for various commercial and medical applications.
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    Mud crab (Scylla serrata) shells for the removal of humic acids from Santa Barbara well water
    Asdillo, Reina Jean A. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2010-04)
    The chemical contamination of drinking water from a wide range of contaminants such as humic acids can potentially lead to health-related in living organisms, especially humans. In rural areas of the Philippines, the use of low cost methods to remove water pollutants is, therefore, of great interest. In this study, osterized mud crab (Scylla serrata) shells or exoskeletons from cooked crab wastes were used to remove humic acids from the Santa Barbara well water. Adsorption experiments were done to evaluate its capacity to remove humic acids from the well water. Adsorption Isotherms and Fourier Transform Infrared Spectroscopy were employed to study the characteristics of the adsorption of humic acids onto the OSSE (osterized Scylla serrata exoskeletons). Adsorption experiments showed that at an average 1.0010 g of OSSE and after six hours of agitation, an average 74.95% of humic substances were removed from 50 mL of Montinola, Santa Barbara well water sample. Isotherm experiments showed that the experimental data can be fitted in both Langmuir and Freundlich models with low K values of 0.0235 L/mg and 0.4450 (mg/g)(L/mg), respectively. Based on the results of the above experiments, OSSE is a good adsorbent for humic acids in well waters (although more research need to be done on the removal of the substances remaining in the water after OSSE treatment) and the U-OSSE (used osterized Scylla serrata exoskeletons) can possibly be recycled.
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    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
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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.