• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.122-126
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• 2002

Contaminant transport in porous media is characterized by solving an advection-dispersion equation(ADE). The ADE can cover equilibrium phenomena of interest, which include sorption, decay, and chemical reactions. Among these phenomena, sorption mechanism is described by several types of sorption isotherm. If we assume the sorption isotherm as linear, the solution of ADE can be easily procured. However, if we consider the sorption isotherm as non-linear isotherm like a Dual Reactive Domain Model (DRDM), the resulting differential equation becomes non-linear. In this case, the solution of ADE cannot be easily acquired by an analytic method. In this paper, we present the numerical analysis of ADE using a DRDM. The results reveal that even if sorption data may be fitted well using linear or non-linear isotherm, the characteristics of contaminant transport of the two cases are different from each other. To be concrete, the retardation of linear isotherm has stronger effect than that of the DRDM. As the non-linearity of sorption isotherm increases, the difference of retardation effects of the two cases becomes larger. For a pulse source, the maximum concentration of the linear model is higher than that of the DRDM, but the plume of the DRDM moves faster than that of the linear model. Behaviors of contaminant transport using the DRDM are consistent with common features of a linear model. For instance, biodegradation effect becomes larger as time goes by The faster the seepage velocity is, the faster the plume of contaminant moves. The plume of the contaminant is distributed evenly over overall domain in the event of high dispersion coefficient.

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.276-281
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• 2022

BACKGROUND: Plastics that are used in our daily lives largely end up in the environment. In agricultural environments, plastic wastes and microplastics can be found due to the uses and improper management of plastic products (e.g., vinyl greenhouses and mulching vinyl). Microplastics can also interact with contaminants in the agricultural environment. Therefore, this study was set to investigate the sorption characteristics of tetracycline, one of widely used antibiotics, on microplastics. METHODS AND RESULTS: The sorption tests were carried out with the tetracycline solutions (0-30 mg L^-1) and microplastic films prepared from low density polyethylene (LDPE) and polyvinyl chloride (PVC). The residual tetracycline concentrations were analyzed and fitted to the Freundlich and Langmuir isotherm models. The tetracycline sorption patterns on LDPE and PVC films were described better with the Freundlich isotherm model than the Langmuir isotherm model. The isotherm model parameters suggested that the maximum sorption amount of tetracyline was greater for PVC, while the sorption affinity was greater for LDPE. CONCLUSION(S): Different types of microplastics can have different sorption characteristics of tetracycline. Therefore, there is a need for continuous research on the interaction of various types and shapes of microplastics and contaminants in the environment.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Nuclear Engineering and Technology
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• v.33 no.3
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• pp.261-269
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• 2001

In this study, sorption experiments of uranium onto silica colloids were carried out and the effects of important geochemical parameters such as pH, ionic strength, carbonate concentration, colloid concentration, and total concentration of uranium were investigated. The sorption coefficients of uranium for silica colloids named as pseudo-colloid formation constants were about 10$^4$~ 10$^{5}$ mL/g depending on the experimental conditions. The effects of the geochemical parameters were found to be important in the sorption of uranium onto silica colloids. A Langmuir type sorption isotherm of uranium between silica colloids and the solution phase was also presented. The sorption mechanisms were explained by analyzing the effects of the geochemical parameters.

• Journal of the Korean Geotechnical Society
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• v.27 no.4
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• pp.43-50
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• 2011

Steel-making slag was investigated as reactive material for removal of cadmium in coastal area. Batch experiments of the sorption isotherm experiment and kinetic sorption experiment were performed. Result of sorption isotherm was more adequately described by Langmuir model than Freundlich model and theoretical maximum capacity (${\beta}$) of cadmium onto steel-making slag was found. Results of kinetic sorption experiments were evaluated by pseudo second order model to investigate sorption characteristics of cadmium onto steel-making slag. Results showed that the equilibrium sorption amount of cadmium (q$q_e$) increased and the rate constant ($k_2$) and initial sorption rate (h) decreased as the initial cadmium concentration increased. The $q_e$ with simulated sea water was similar to that with deionized water and $k_2$ and h with simulated sea water was lower than those with deionized water. Results of kinetic experiments could be used to predict the result from sorption isotherm, since equilibrium sorption amounts calculated by pseudo second order model generally agreed with those measured from sorption isotherm. The reaction time for the target removal rate could be calculated by the pseudo second order model using kinetic sorption tests results.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.302-305
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• 2002

Scoria is a bomb-sized, generally vesicular pyroclast that is red or black in color and light in weight. In this study, scoria from Cheju was examined for the use as a sorbent. It is composed of plagioclase, olivine, hornblende, pyroxene, and glass, with an average composition of 49.84% SiO$_2$, 14.07% A1$_2$O$_3$, End 9.14% Fe$_2$O$_3$. Studies on kinetic isotherm sorption of Zn(II) onto scoria under various parameters such as initial zinc concentration, particle size, and adsorbent/adsorbate ratio were carried out using an agitated batch. The results suggest that the smaller scoria size and the larger adsorbent/adsorbate ratio produce the higher degree of Zn(II) removal. More effective removal also appears at lower initial Zn concentration. The sorption behavior of Zn(II) onto scoria seems to be mainly controlled by cation exchange. Studies on equilibrium isotherm sorption of other heavy metals (Pb, Cu, Cd) onto scoria were also conducted and compared with those onto powdered activated carbon (PAC) and non-organic matter scoria (NOS), The results suggest that the Cheju scoria has the slightly higher sorption capability than PAC and NOS, and the order of the effective sorption onto scoria and PAC is Pb > Cu > Zn > Cd. The monometal sorption onto scoria is more stronger than the competitive sorption.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.521-528
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• 1999

As the size of our industry and population inclose, the byproducts such as municipal solid wastes, industrial wastes are in the increasing phase. The treatment of such things is rising as a social problem. Today, the final disposal of these wastes depends mostly on the landfill, and the sanitary landfill is required and designed for preventing soil and groundwater contamination. Clays have been used for a liner material of a sanitary landfill, however, the high quality clay is hard to come by and quite expensive as a lining material in our country. Using the waste lime produced abundantly every year from chemical processes was studied here, made from the proper mixing of the bentonite and the waste lime meets the regulations from the USEPA. The soil property index tests (sieve analysis, specific gravity test Atterberg limit test) were performed, and at last to confirm the sorption characteristics of the bentonite and the waste lime the sorption isotherm equilibrium test and the sorption isotherm were performed with Toluene and Ethylbenzene which are the main components of the leachate from the landfill.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.78-84
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• 1997

Batch and column tests were performed to investigate the sorption capacity of bottom soils of Kimpo metropolitan waste landfill. Sorption capacity and sorption isotherm from the batch test for inorganic and heavy metal substances and retardation capacity of heavy metals from the column test are obtained. It was recognized from the tests that the samples match well with Freundlich isotherm and marine clay has good sorption capacity for potassium and heavy metals such as lead and cadmium. The soil samples with different geologic origins did not show significant differences in the sorption capacity of tested components.

• Membrane Journal
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• v.3 no.2
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• pp.79-82
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• 1993

The sorption equilibria and permeabilities for $CO_2$ in a homogeneous membrane of polystyrene with the glass transition temperature of $95^{\circ}C$ were measured at a temperature of $60^{\circ}C$ and gas pressures up to 1.6 MPa and 2.5 MPa, respectively. The sorption isotherm had the form af dual-mode sorption model at low gas pressures, but became linear at pressures above 1.3 MPa. The linear portion of the isotherm extrapolated to the origin. The pressure dependence of the rnean permeability coefficient deviated upward from the dualsrhode mobility model prediction. It was found that the glass transition was brought out by the plasticization action of sotbed $CO_2$ at a gas pressure of 1.3 MPa from the sorption isotherm. And this result was consistent with an increase in the mean permeability coefficient with applied gas pressure.

• Journal of the Korean Geotechnical Society
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• v.26 no.9
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• pp.37-45
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• 2010

Sorption characteristics of arsenic on furnace slag were investigated to remove arsenic from groundwater using furnace slag, which is industrial waste generated from steel company. Adsorption isotherm experiments and kinetic sorption experiments were performed and the chemical characteristics of supernatants from these experiments were analyzed. Results showed that all supernatants were alkaline (above pH 9) and the highest ion concentration in the solution was found with calcium (30~50 mg/L). Results of adsorption isotherms were more adequately described by the Freundlich model than Langmuir model. From adsorption isotherms experiments, it was noted that the adsorption amount of As(V) was 87% higher than that of As(III). Results of kinetic sorption experiments were more properly fitted by pseudo second order (PSO) model than pseudo first order model. Equilibrium adsorption amount ($q_e$) and relaxation time ($t_r$) calculated from PSO model increased with initial concentration of arsenic. Equilibrium adsorption amount of As(V) was higher than that of As(III) and relaxation time of As(V) was shorter than that of As(III). Adsorption isotherm results could be predicted by kinetic adsorption results, since equilibrium adsorption amount calculated through PSO model generally agreed with equilibrium adsorption amount measured from adsorption isotherm.