• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.114-122
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• 1995

Complexation experiment between humic acid and heavy metal cations was conducted to clear information on heavy metal adsorption by soil organic constituent. The absorbance of UV-visible light of humic acid-metal complexes increased with increasing wavelength, and the order of their absorbance was in the order of Zn->Cd->Cu- saturated humic acid. Carboxyl and phenolic OH groups participated in the complex formation between heavy metal cations and functional groups of humic acid, and the amounts complex was in the order of $Cu^{+{+}}$ > $Zn^{+{+}}$ $\geq$ $Cd^{+{+}}$. The stability constants of humic acid-metal complexes increased with increasing pH, and the order of first stability constants was $Zn^{+{+}}$ > $Cd^{+{+}}$ > $Cu^{+{+}}$, and those of second and overall stability constants were $Cu^{+{+}}$ > $Zn^{+{+}}$ > $Cd^{+{+}}$. With increasing pH, the average binding numbers betwen heavy metal cations and functional groups of humic acid increased the order of $Cu^{+{+}}$ > $Zn^{+{+}}$ > $Cd^{+{+}}$. It was postulated that two types of complexations between heavy metal cations and functional groups of humic acid. One was the reactions in which only carboxyl groups participated to form complexes, and the other was those in which both carboxyl and phenolic OH groups simultaneously participated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.69-77
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• 2004

Degradations of pine, yellow poplar and sweet gum by two fungi, Pycnoporus cinnabarinus and Trichophyton rubrum LSK-27 were investigated. P. cinabarinus degraded pine block samples much faster than T rub rum LSK-27, whereas P. cinnabarinus and T rubrum LSK-27 degraded yellow poplar and sweet gum at almost the same rate. In an effort to get a better understanding of how fungi degrade lignin in wood, contents of various functional groups were analyzed. After three-months of degradation of pine flour by these fungi, the following changes were observed: an increase in condensed phenolic OH group and carboxylic acid group content, a decrease in the guaiacyl phenolic OH content, and little change of aliphatic OH group content. Further studies in the degradation of pine flour by P. cinnabarinus indicated that the increase in condensed phenolic OH group content and the decrease in guaiacyl phenolic OH group content occurred in the first month of the degradation. The changes of functional group contents in the degradation of unbleached softwood kraft pulp by P. cinnabarinus had the same trends as those in the degradation of pine flour. That is, structural alteration of lignin due to the kraft pulping process had little effect on how P. cinnabarinus degraded lignin.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.251-259
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• 1987

Humic acids extracted from decomposing plant residues were characterized by infrared(IR) spectra. The IR spectra were further interpreted by chemical analyses for oxygen-containing functional groups such as carboxyl, phenolic, alcoholic, carbonyl, and quinionic groups. 1. The IR spectra obtained in this study were divied into three categories: spectra of humic acids from grain crop straws of rice, barley, wheat and rye produced Type I, while that from wild grass hay yielded Type II, and those from forest tree litter of the deciduous and conifers were led to give Type III. 2. There were no significant changes in the absorption bands observed among humic acids extracted at various stages of decomposition of a given Plant material. 3. The absorption band at about $3,430cm^{-1}$ represents the presence of hydrogen-bonded hydroxyl groups, phenolic-OH groups being the major component. 4. A close relationship was found between the total acidity and the content of phenolic-OH groups of humic acids. The content of carboxyl groups maintains a direct relationship with the content of total hydroxyl groups, and such a close relationship also exists between the content of alcoholic hydroxyls and that of total hydroxyl groups. 5. Overlapping of the absorption bands of carbonyl groups and quinones renders it difficult to make differentiation between the two. 6. A variety of non-armoatic cyclic hydrocarbons appears to be a structural component as evidenced by a sharp absorption peak near $995-1000cm^{-1}$.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.20-24
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• 2007

The effects of phenolic acids on inhibition of browning by the Maillard reaction were investigated with a glucose-glutamic acid model for doenjang with citric acid as the antibrowning agent and phenolic acid as its synergist. Five phenolic acids, cinnamic, coumaric, caffeic, hydroxybenzoic, and protocatechuic acids, were used. In order to investigate the antibrowning capacity, 0.1M glucose, 0.1M glutamic acid, 50mM citric acid, and 1mM phenolic acid were dissolved in 1M phosphate buffer (pH 7.0), heated at $50^{\circ}C$ for 24hr in the presence of 0.2mM $FeCl_{2}$, and stored at $4^{\circ}C$ or $30^{\circ}C$ for four weeks. Phenolic acid addition more efficiently inhibited browning during storage at $30^{\circ}C$ than at $4^{\circ}C$, without changes in pH. Hydroxybenzoic acid was the most efficient and increased the antibrowning capacity by 13% compared to sample without phenolic acids. Although caffeic and protocatechuic acids inhibited most the formation of 3-deoxyglucosone or fluorescence, they increased browning by forming colored complexes between two hydroxy groups of phenolic acids and iron ions. Hydroxybenzoic acid will be able to be a useful synergist of citric acid, an antibrowning agent in doenjang, since it is permitted for doenjang.

• The Korean Journal of Community Living Science
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• v.27 no.3
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• pp.343-350
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• 2016

The antioxidant activity was examined on ultra-fine powdered (UFP) Ulmus davidiana (U. davidiana) var. japonica. The average particle size of UFP or commercial powdered (CP) was $1-3{\mu}m$ or $100{\mu}m$. The extraction was performed using either ethanol (EtOH) or hot-water. Contents of phenolic compound of CP and UFP U. davidiana extracts in EtOH was 40.38 and 65.61 mg/g, respectively. In DPPH, EtOH extract of UFP U. davidiana showed a significantly greater activity than hot-water extract at 40 and $200{\mu}g/mL$. At $200{\mu}g/mL$, the activity was over 90% in all groups. The reducing power of UFP U. davidiana var. japonica in EtOH extraction was 74.3%, which was significantly greater than in other samples (p<0.05). In addition, reducing powder was significantly higher in UFP-EtOH than in other samples at all concentrations except for $0.32{\mu}g/mL$. The above results suggest that EtOH extraction of U. davidiana showed slightly higher DPPH radical scavenging activity, and ultra-fine powder of U. davidiana extracts may show higher antioxidative activities based on reducing power.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.86-91
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• 1997

Complexation of primary alkylammonium ions by 1, 3-distal calix[4]arene diesters was studied by NMR spectroscopy. The guest alkylammonium ions are found to bind mainly to the two ester moieties and are oriented outward with respect to the cone cavity of the host, forming exo-type complexes unlike the case of alkylammonium-calix[6]arene systems. Measurement of T1 also revealed that the primary binding site is the two ester moities and phenolic OH groups. The temperature dependence of the chemical shifts of phenolic OH protons in these diesters correlates with the basicity of the solvent moderately well and the temperature coefficients of their chemical shifts are found to significantly decrease upon complexation with propylammonium ion.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.11-16
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• 2005

Humic substances(HS) from raw and process waters at a conventional water treatment plant were isolated and extracted by physicochemical fractionation methods to investigate their characteristics. They are characterized for their functionality, chemical composition, and spectroscopic characteristics using FT-IR(Fourier transform infrared) and $^1H-NMR$(proton nuclear magnetic resonance) spectroscopy. Humic fraction gradually decreased from 47.2% to 26.4%(from 0.97 to 0.54 mgC/L) through conventional water treatment processes. Concentration of phenolic groups in the HS fraction gradually decreased from 60.5% to 21.8%(from 12.2 to $6.0\;{\mu}M/L$ as phenolic-OH) through water treatment. In the case of carboxylic groups, the concentration increased from 39.5% to 46.9%(from 7.9 to $10.6\;{\mu}M/L$ as COOH) by pre-chlorination, but gradually decreased to 34.2%($9.4\;{\mu}M/L$ as COOH) through sedimentation and sand filtration. From the results of the FT-IR and $^1H-NMR$ spectra of HS, the content of carboxylic groups increased and ratio of aliphatic protons to aromatic protons($P_{Al}/P_{Ar}$) also increased through water treatment, which indicated the increase of aliphatic compounds.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.57.1-57.1
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• 2011

The effects of relative humidity on the properties of the porous $ZrO_2$ ceramics were investigated in terms of the curing behavior of phenolic resin as a binder. The $ZrO_2$ powders containing 5wt% of phenolic resin were conditioned in a consistent chamber condition at a temperature of $50^{\circ}C$ and different humidity levels (25, 50, 75, and 95%) for 1 h. The exposure of humid atmosphere caused changes of density and microstructure in the green bodies. The higher level the powders were exposed to the humid atmosphere, the lower green density was obtained and the more irregular microstructure was observed due to aggregation by the curing of phenolic resin. After firing, the porosity of specimens has risen from 35.7% to 38.1% and Young's modulus has declined in response to the variation of green density. These results could be explained by the degree of resin cure which was associated with the area under the exothermic peak enclosed by a baseline of DSC thermogram curve. Also, the curing behavior of phenolic resin according to relative humidity has been confirmed by decrease of ether groups which have interacted with the phenolic-OH group and the hexamine as a curing agent. Consequently, it could be demonstrated that increase the relative humidity during fabrication of porous $ZrO_2$ diminished the compaction and properties of specimens after firing owing to curing of phenolic resin.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.755-762
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• 1995

A phenolic resin industrial wastewater containing about 41,000 mg/l of phenol and 2,800 mg/l of formaldehyde was biologically treated by a mixed culture GE2 immobilized on ceramic beads. This study was carried out with three experimental groups : Control-only added the sludge of papermill wastewater ; GE2 treatment-added GE2 to Control ; Ceramic treatment-applied ceramic carrier to GE2 treatment. When the original wastewater was diluted 80 times with aerated tap-water, influent COD$_{Mn}$ WaS 1,140 mg/l and that of the effluent was in the range of 22-35 mg/l, which was not much different among the experimental groups. However, at 20-times dilution, influent COD$_{Mn}$ was 4,800 mg/l and the effluent COD$_{Mn}$ of Control, GE2 treatment and Ceramic treatment was 179, 128 and 94 mg/l, respectively. COD$_{Mn}$, removal efficiency by Ceramic treatment was the highest, at 98.0%. At this time, the effluent phenol concentration of Control, GE2 treatment and Ceramic treatment was 10.71, 7.93 and 5.60, respectively. As the dilution times decreased, the removal efficiency of COD$_{Mn}$ and phenol did not change much, but COD$_{Mn}$ and phenol concentration of the effluent increased. Consequently, it is likely that the phenolic industrial wastewater containing phenol and formaldehyde can be biologically treated using a GE2 and ceramic carrier and that at 40-times dilution, the effluent completely meets the effluent standards for industrial wastewater treatment plant.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.240-246
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• 2005

Humic substances HS) from process waters at advanced water treatment plant consisted of GAC and Ozone/GAC processes were isolated and extracted by physicochemical fractionation methods to investigate their characteristics. They are characterized for their functionality, chemical composition, spectroscopic characteristics using FT-IR and $^1H$-NMR spectroscopy. Humic fraction gradually decreased from 36.3% to 24.2% from 0.45 to 0.30 mgC/L) through ozonation and carbon adsorption. The humic fraction was isolated into the phenolic and carboxylic groups using A-21 resin, and the concentration of phenolic groups gradually decreased from 38.4% to 23.5% (from 4.9 to $3.2\;{\mu}M/L$ as phenolic-OH) through ozonation and carbon adsorption. In the case of carboxylic groups, the concentration decreased from 61.6% to 43.3% (from 7.8 to $5.8\;{\mu}M/L$ as COOH) through the water treatment processes. On the other hand, concentrations of those roups decreased from 38.4% to 24.0% and 61.6% to 44.9% through carbon adsorption without ozonation, respectively. The structural changes of HS identified from FT-IR and $^1H$-NMR were consistent with the results from the isolation of functional groups in HS.