• Korean Journal of Agricultural Science
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• v.27 no.2
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• pp.135-140
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• 2000

The mobility of sulfate in soils defends on several factors including redox potential, soil mineralogy, pH, and the presence of other anions that compete for sorption sites with sulfate. The proposed model of adsorption mechanism for sulfate postulated that reaction is between anions in solution and charged surfaces of soil particles. With appropriate choice of parameters obtained from the adsorption-desorption experiments, the equation of transport model adapt an empirical approach, capable of handling most general equilibrium adsorption isotherms, suitable for multispecies systems.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.95-103
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• 2004

This study has been assessed the influence of applying sewage sludge to soil amendments on the sorption properties, and leaching potential of three commonly used organophosphorus pesticides, Diazinon, Fenitrothion, and Chlorpyrifos. A sandy soil with a low content of organic carbon was treated with sewage sludge with a ratio sandy soil sludge ratio of 30:1. The sorption was determined with the batch equilibrium technique. The sorption isotherms could be described by Freundlich equation. The Freundlich constant, K value which measures sorption capacity, were 3.97, 9.94, 22.48 for Diazinon, Fenitrothion, Chlorpyrifos in non-amended soil. But in amended soil, K value was 12.58, 28.47, and 61.21 for Diazinon, Fenitrothion, and Chlorpyrifos. The overall effect of sewage sludge addition to soil was to increase pesticides adsorption, due to the high sorption capacity of the organic matter. The effect of sludge on the leaching of pesticides in the soil was studied using packed soil columns. Total recoveries of pesticides in soil and leachate with leaching in soil column, were in the range of about 73∼84%, was reduced with the passage of time. Diazinon moved more rapidly than Chlorpyrifos in the unamended soil due to greater sorption and lower water solubility of Chlorpyrifos. Total amounts of pesticides leached from the sewage sludge amended soils were significantly reduced when compared with unamended soils. This reduction may be mainly due to and increase in sorption in amended soils, as a consequence of the increase in the organic matter content.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.365-370
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• 2004

To invesligate the characteristics of silica sorption on soils silica sorption experiments were conducted with 9 soils at 4 pH levels (5, 6, 7, and 8). Silica sorption increased in great extent with increase of pH. At the same pH level silica sorption increased linearly with increase of equilibrium $SiO_2$ concentration. Silica sorption characteristics was C-type. The C-type slope, i.e., the slope of linear regression of silica sorption isotherm, increased exponentially with increase of pH in all soils. Log(C-type slope) increased linearly with increase of pH in all soils. The slopes of linear regression were similar in most soils from 0.29 to 0.34 except Sachon and Jonggog soil. None of the soil properties showed any correlation with the slope of linear regression of Log(C-type slope) to pH. Only $Fe_o$ (oxalate extractable Fe oxides) was significantly correlated with the Log(C-type slope) at pH 7 in simple correlation analysis, and was shown to be the principal contributor as determined by standardized multiple linear regression.

• 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.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.128-133
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• 1997

This study was conducted to evaluate the adsorption, desorption, leaching and degradation pattern of fungicide fluazinam in the soil environment under the laboratory conditions. The mode of isothermal adsorption of fluazinam in soil was coincident with the Freundlich equation. The adsorption amount of fluazinam was much higher on soils containing organic matter than on soils oxidized with hydrogen peroxide. The presence of organic matter, humic acid or fulvic acid, increased the adsorption amount of fluazinam on soils. The Freundlich constant K was much higher in soil added with humic acid than in soil added with fulvic acid. The desorption ratio of fluazinam adsorbed to soil was increased by removal of organic matter. In leaching experiment using soil column, the fluazinam applied on the soil surface was not moved down to the bottom of soil and was not detected in leachate water. The degradation of fluazinam was faster in Soil I with rich organic matter than Soil II with poor organic matter, in non-sterilized soil than sterilized soil, and in flooded soil than unflooded soil.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.72-79
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• 1997

본 실험은 제초제인 2,4-D, dicamba, 및 MCPP의 토양에서의 이동을 확인하고 평가하기 위하여 토양종류에 따른 이들 제초제의 흡착과 휘발을 일정시간 동안 조사하였다. 제초제의 토양중 흡착은 batch isotherm으로 조사하였는데, MCPP와 2,4-D는 Freundlich식에서 직선으로 나타났으며, dicamba는 곡선으로 나타났다. Silty clay 토양에서 MCPP의 K$_d$ 및 K$_{fr}$값이 가장 높았으며, loamy sand 토양에서는 dicamba의 K$_d$, K$_{fr}$값이 가장 낮았다. 전반적으로 silty clay 토양에서 K$_d$, K$_{fr}$값이 높았고 N값은 낮았다. 토양에 살포된 제초제의 약 40%가 처리 25일 경과시 휘발되거나 분해되었으며, 이들 제초제중 2,4-D가 dicamba와 MCPP에 비하여 분해 및 휘발속도가 빨랐다. 모든 토양에서 이들 제초제의 분해 및 휘발속도는 공기에 노출된 초기에 현저하게 빠른 것으로 나타나고 있다. 본 연구의 결과는 자연환경중에서 이들 제초제의 이동 및 잔류 현황을 예견하는데 사용될 수 있을 것으로 사료된다.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.1-4
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• 1974

The application of the Distribution Law to soil-pesticide systems yielded the following empirical implications : 1) The amount of the pesticide adsorbed by a soil is negatively proportional to the soil water content. 2) At a given soil water content the amount adsorbed is proportional to the Kd of the soil. 3) The effect of soil water content on the amount of the pesticide adsorbed diminishes with increasing magnitude of the Kd.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.341-349
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• 2005

Soil adsorption study was carried out to define the mobility of pesticides and to evaluate leaching potential in soils. Nine pesticides including metolcarb, molinate, fenobucarb, isazofos, diazinon, fenitrothion, dimepiperate, parathion and chlorpyrifos-methyl were subjected to adsorption experiment for four types of soils, such as upland, paddy, forest and volcanic ash soil. Based on Koc values, metolcarb and molinate were classified as mobile, fenobucarb as mobile or moderately mobile isazofos as moderately mobile, diazinon, fenitrothin, dimepiperate, and parathion as slightly or moderately mobile and chlorpyrifos-methyl as slightly mobile. Two evaluation methods, Groundwater Ubiquity Score (GUS) index and standard indices of soil-chemical adsorption and biodegradation (half-life), were used for the estimation of pesticide leaching potential. Leachabilities of metolcarb, molinate and fenobucarb were evaluated as high, and isazofos, dimepiperate and diazinon as a little potential, while fenitrothion, parthion and chlorpyrifos-methyl showed very low leaching potential. The leaching potential of pesticides was determined on the basis of intrinsic properties of the pesticides and the soil properties. Among the soil properties, organic matter gave a great influence on the leachability in soil. Therefore, leachabilities of the pesticides used were expected less in Sineom soil with relatively higher organic matter than Gangseo, Jungdong and Yesan soil with lower organic matter.

• Geotechnical Engineering
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• v.11 no.2
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• pp.121-138
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• 1995

The Langmuir competitive model and the IAS(ideal adsorption solution) model were eveluated and compared in a multisolute adsorption study using five organic compounds (phenol, 2, 4-dichlorophenol, 2, 4, 6-trichlorophenot brucine, and thiourea) and two soils. The chemicals were evaluated individually and in mixtures. In general, the IfS model predicted the equilibrium concentration of a chemical in a mixture better than the Langmuir model. The Langmuir model underestimated the sorption of phenol when the concentration of another compound in a mixture with phenol was high. Neither of the models predicted satisfactorily the equilibrium concentration of thiourea in the mixtures. Thiourea is an aliphatic compound while the other four chemicals are aromatic compounds.

• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.22-29
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• 1984

The Freundlich-type adsorption isotherms were obtained in this study on the adsorption of linuron, bentazon, trifluralin and butachlor by soils. A strong correlation was shown between soil organic matter content and the adsorption of linuron. Soils with high organic matter content adsorbed more linuron. There was no significant correlation between the adsorption of bentazon and clay content. There was a tendency that increase in organic matter content acts against the adsorption of bentazon. Repulsive forces seemed to exist between negatively charged soil particle surfaces and betazon molecules which become weakly charged negative ions in soil solution. Organic matter content and cation exchange capacity appeared to be enhancing the adsorption of trifluralin and butachlor. Clay content was not significantly correlated with the adsorption of these herbicides. Trifluralin was adsorptive to the greatest extent, followed by linuron and butachlor, bentazon being the least.