• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.162-168
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• 2001

This study was conducted to evaluate the degradation, adsorption and desorption and leaching of acetamiprid in soils. The half-life of acetamiprid in field condition was $1.7{\sim}3.3$ days in Bokhyun soil and, in case of laboratory condition, 15.5 days. Adsorption of acetamiprid was equilibrated in 12 hours incubation. In adsorption experiment using modified soils, such as oxidized soil, oxidized soil added humic acid, fulvic acid, kaolinite or montmorillinite, adsorption rate of acetamiprid was the highest in the oxidized soil added fulvic acid. The desorption rate was the lowest in the oxidized soil added fulvic acid. The adsorption and desorption results should be suggested that acetamiprid could be strongly adsorbed with soil humic materials, especially fulvic acid. When the mobility of acetamiprid in soil was calculated according to GUS (Groundwater Ubiquity Score) equation, it was prove to non-leacher, and it was confirmed in the leaching experiment with soil column. Most of acetamiprid was remained in the upper 30 cm of the soil column after eluting with water and it was not even detected in leachate.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.35-40
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• 1993

In order to find the effect of humic substances affecting to the behavior of diazinon in submerged soil, the adsorption rate of diazinon was investigated with different soil humic substances like as humin, humic acid and fulvic acid. The adsorption rate of diazinon(1.8 ppm) was 12.4% in humin, 11.9% in fulvic acid and 10.4% in humic acid at 1% concentration of humic substances, also were not much differences at 0.1 and 0.5%. But it showed much similar level ($10.2{\sim}10.6%$) at 1.0% concentration in 5ppm diazinon treatment. As a result, because adsorption rate of diazinon on humic substances were about $10{\sim}12%$, disappearance of diazinon in submerged soil may be affected by the other factors such as soil microorganism.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1321-1326
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• 2005

As a results of this research, the Nakdong River consisted of 43% of hydrophobic fraction, 39% of hydrophilic fraction, and 18% of transphilic fraction. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional roup(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores. The carboxylic acid functional group caused more fouling than the phenolic group.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.70-78
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• 1998

This study was conducted to investigate the adsorption-desorption characteristics of herbicide paraquat on clay minerals, humic materials, and soils under the laboratory conditions. Adsorption time of paraquat on clay minerals was faster than organic materials and soils. Adsorption amount on montmorillonite, 2:1 expanding-lattice clay mineral, was largest among the adsorbents tested. The adsorption capacity of paraquat was approximately 21 % of cation exchange capacity in soils, 45.1 % in kaolinite, and 80.6% in montmorillonite. Humic materials, humic acid and fulvic acid isolated from soil II, adsorbed larger amount of paraquat than kaolinite and soils. Distribution of tightly bound type of paraquat was larger in clay mineral and soils but loosely bound type was larger in humic acid and fulvic acid. In oxidized soil, the adsorption amount of paraquat was decreased to 85.1-95.5% of original soils. Distribution of unbound and loosely bound type of paraquat was decreased in oxidized soil but tightly bound type was increased. The competition cations decreased paraquat adsorption on humic materials and soils but not affected on montmorillonite. No difference was observed as the kinds of cations. In cation-saturated adsorbents, the adsorption amount was decreased largely in humic materials and soils but decreased a little in montmorillonite. The tightly bound type of paraquat in all adsorbents was not desorbed by pH variation, sonication, and cation application but loosely bound type was desorbed. However, the desorption amount was different as a kinds of adsorbents and desorption methods.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.162-168
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• 1993

This research was conducted to assess the influence of humic or fulvic acid on Bentazone phytotoxicity using a bioassay with hydroponically grown cabbage (Brassica campestris subsp. napus var. pekinensis Makino). Concentrations of Bentazone in the water culture media were ranged from 0 to 32 ${\mu}M $ and those of the organic ligands were 1.0mM as a soluble carbon. Media were prepared in a complete factorial combination with pHs of 4.5, 6.5 and 8.5. The phytotoxicity indices on growth rate and dry weight decrement were employed to evaluate the effects of organic ligands on the Bentazone phytotoxicity. Humic or fulvic acid without Bentazone treatment enhanced the growth of cabbage and this effect was evident at low pH of 4.5. Bentazone led to chlorosis and necrosis on cabbage leaves resulting in the decreases of dry and fresh weights and growth rate. This phytotoxic effect was increased with Bentazone concentration and evident at low pH. At pH 4.5, dry weight was decreased about 63% with 8${\mu}$M of Bentazone treatment. Effective concentration of Bentazone causing 50% decreases in fresh weight as compared to the control was estimated to be 21${\mu}$M. Presence of organic ligand reduced the phytotoxicity of Bentazone to cabbage significantly by increasing yields and growth rates as compared to the treatment of Bentazone alone. At pH 4.5, fulvic acid reduced phytotoxicity of Bentazone upto 46%, and this efficiency of fulvic acid was better than that of humic acid under the same condition.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.341-349
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• 1987

Fulvic acids extracted from seven plant materials were tested. The IR spectra and the data obtained from chemical analyses in terms of oxygen-containing functional groups complemented one another. Selected samples covered straws of grain crops (rice, barley, wheat and rye), hay of wild grass, and leaves of trees (deciduous and coniferous). 1. No significant variation in IR spectra of fulvic acids was observed among samples taken from different plant residues and at different stages of humification. 2. Oxygen-containing functional goups, such as carboxyls, phenolics, alcoholics, carbonyls, and quinones were identified on IR spectra and confirmed by chemical analyses. 3. The acidity of fulvic acids was directly related with the content of carboxyl groups. 4. Alcoholic hydroxyl groups predominated over phenolic hydroxyls. 5. The major part of fulvic acid structure appeared to be strongly aliphatic in many respects of chemical characteristics.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.4
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• pp.227-230
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• 1973

To elucidate the effect of the organic carbon compounds included in a separate from glutamic acid fermentation residue (G. A. F. R) on the improvement of the physico-chemical properties of soil, on a soil low in organic matter content, treated with G. A. F. R and compost, observations on the total organic matter, humic acid, fulvic acid, C. E. C. and the development of aggregates were made. From the results of the investigations it was concluded that, the organic carbon compound in the tested G. A. R. F. is more effective than compost in increasing the total organic matter, humic acid, fulvic acid and C. E. C. of soil and in enhancing the development of soil aggregates.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.585-589
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• 1994

The complexation of cadmium(II) with a well characterized local soil fulvic acid was investigated at different solution pH and fulvic acid concentration using ion selective electrode. The stability constants were determined using a continuous distribution model based on Scatchard Plot; this model takes into consideration the diversitv of cation binding sites on a naturally occurring organic macromolecules even if the nature of the binding sites may not be known. The mean value of $logKi(\mu)$ was found to increase at higher pH(pH 4.0: ${\mu}=3.79{\pm}0.74$ l\;mol^{-1}; pH 6.0: ${\mu}=4.51{\pm}0.78$ l\;mol^{-1}$), and in more dilute fulvic acid concentration([FA] = 50 mgl$^{-1}: {\mu}=4.16{\pm}0.60$ l\;mol^{-1}; [FA]=151 mgl$^{-1}:{\mu}=3.75{\pm}0.5\;l\;mol^{-1}$). The intrinsic constant(logKint) for binding at the strongest site was measured to be around $4.72\;l\;mol^{-1}$ at both pH4.0 and 5.0, but was found to be increased to $6.03\;l\;mol^{-1}$ when pH was 6.0.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.777-781
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• 1994

Three humic acids (HA) and one fulvic acid (FA) are extracted from soils of the Okch'on Basin (Koyesan, Yongkwang and Taejon), and are purified and characterized using $^1H,\;^{13}C$ NMR, and IR spectroscopic methods. The results are compared with one another and with commerical humic acid (Aldrich Co) and aquatic humic acid from Gorleben underground aquifer in Germany. The IR and $^1H\;and\;^{13}C$ NMR spectral features are found to be nearly identical, suggesting that humic substances formed in the Okch'on Basin have quite similar chemical properties. These humic substances from Okch'on Basin soils have undergone low degree of aromatic condensation and have high contents of aliphatic functionalities including carbohydrates.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1046-1054
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• 2006

The raw water DOC contained 39.3% of hydrophilics, 42.9% of hydriophobic, and 17.8% of transphilic. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional group(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The fouling mechanisms on the membrane surface and into its porous structure were analyzed in terms of several kinetic models. In order to analyze the fouling kinetics, the various kinetic models described in this paper were used to fit the experimental results. The kinetic models and kinetic constants obtained for each operation condition. The permeate flux was rapidly declined by simultaneous pore blocking and cake formation. Also, the permeate flux declined with decreasing internal pore size resulted from organic deposition into the membrane pore. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores.