• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.32-39
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• 2000

To investigate the adsorption-desorption reaction of Cd by sewage sludge, the adsorption of Cd from $Cd(NO_3)_2$ solutions of concentrations ranging from 5 to $50{\mu}g\;Cd\;mL^{-1}$ by sewage sludge was examined for reaction periods up to 48 hours. The amount of Cd adsorbed as a function of time was measured. The adsorption between Cd in solution and the solid phase could be described by two stages. The initial adsorption of Cd was very rapid, that is, approximately 95% of the added Cd was removed from solution within the first 30 minutes. Further, the greater the concentration of Cd added, the greater was the amount of Cd adsorbed. After the rapid initial decrease of Cd, a slower decline in the Cd concentration resulted which followed first order reversible kinetics. The equilibrium concentrations for the reactions, as well as the time period for the equilibrium reactions were dependent on the initial Cd concentrations. If equilibrium is reached, the amount of Cd remaining in solution is greater when the amount adsorbed is higher, although the percentage of Cd in solution is constant relative to the initial concentration of Cd. Some of the adsorbed Cd was released back to solution since the concentration of Cd after 48 hours was higher than the equilibrium concentration of Cd. However, despite the increased amount of Cd measured, the overall net reaction was a significant adsorption of Cd from solution by sewage sludge.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.17-23
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• 2001

The adsorption and movement characteristics of herbicide pendimethalin was studied in three kinds of soil, sandy loam, silty clay and loam. The results of the batch test and columnexperimentweresummarizedasfollows. The shaking time reached to the adsorption equilibrium of pendimethalin in soils was 6 hours. The adsorption rates of pendimethalin for sandy loam, silty clay and loam were 59.6%, 77.3% and 64.0%, respectively. The adsorption isotherms with the Freundlich equation showed better consistency than that with the Langmuir one. The adsorption coefficients of pendimethalin for soils were 8.0. 16.1 and 9.5. respectively. When breakthrough point was 0.05Co, the breakthrough times reached for soils were 256 minutes, 810 minutes and 420 minutes. respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.19-25
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• 1998

Adsorption characteristics of DMMP and IMPF were investigated using dynamic adsorption method. Adsorbate vapor was forced to Pass at fixed flow rate of 4 mg/I through Cu Cr impregnated activated carbon column at several different flow velocities until the effluent concentrations exceeded 4.0$\times$10$^{-5}$ mg/I. The kinetic adsorption capacity, adsorption kinetic constant, and critical bed weight of the activated carbon were determined for DMMP and IMPF vapors by plotting breakthrough time as a function of carbon weight. A mathematical expression was deduced from our experimental data to represent the relationships between kinetic adsorption capacity and flow velocity. According to our experimental results, the lifetime of DMMP was longer than that of IMPF under the same conditions. Their relationship can be expressed empirically as follows: Tb(DMMP) ＝ 0.9825$\times$Tb(IMPF)-15.368

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.26-34
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• 2005

The effects of soil-chemical contact time (aging) on sorption and desorption of atrazine were studied in soil slurries because aging is an important determinant affecting on the sorption and desorption characteristics of organic contaminants in the environment. Sorption isotherm and desorption kinetic experiments were performed, and soilwater distribution coefficients and desorption rate parameters were evaluated using linear and non-linear sorption equations and a three-site desorption model, respectively. Aging time for sorption of atrazine in sterilized soil slurries ranged from 2 days to 8 months. Atrazine sorption isotherms were nearly linear $(r^2\;>\;0.97)$ and sorption coefficients were strongly correlated to soil organic carbon content. Sorption distribution coefficients $(K_d)$ increased with increasing aging in all soils studied. Sorption non-linearity did not increase with increased aging except for the Houghton muck soil. Desorption profiles were well described by the three-site desorption model. The equilibrium site fraction $(f_{eq})$ decreased and the non-desorbable site fraction $(f_{nd})$ increased as a function of aging time in all soils. In all soils studied, it was found that when normalized to soil organic matter content the concentration of atrazine in desorbable sites was comparatively constant, whereas that in non-desorbable site increased as aging increased.

• Analytical Science and Technology
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• v.13 no.1
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• pp.96-100
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• 2000

The adsorption of heavy-elements to zeolite has been investigated at various adsorptional condition for purification of waste water. Four heavy elements, Cd, Cr, Cu and Pb, were examined, because they are concerned to the major heavy-element contamination. The adsorption efficiencies are measured at the different conditions such as adsorption times and pHs. The practical adsorption was achived and reaches to maximum within 30 minute by using of 2-g zeolite for 50 mL of heavy-element solution. The overall adsorption efficiencies for Cr and Cu are high and become better at low pH. Cd and Pb have 95% of adsorption ratio and this is lower than other two elements. Cadmium shows an abnormally low adsorption at low pH.

• Clean Technology
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• v.10 no.3
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• pp.159-168
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• 2004

Benzene adsorption experiment was carried out for activated carbon and zeolite 13X adsorbents. Single column and dual column packed with two adsorbents were used to investigate the dynamic adsorptive characteristics. Effect of feed flow rate on the breakthrough curve was not significant. Specific adsorption amount of benzene for activated carbon was larger than that for zeolite 13X. On the contrary, adsorption amount per column volume was larger for zeolite 13X column because the density of zeolite 13X was larger. In the dynamic experiment using dual adsorbents column, length of mass transfer zone was changed by the feed direction. Breakthrough time was longer and breakthrough curve was sharper when activated carbon was packed in feed inlet and zeolite 13X was packed in column outlet. Also breakthrough time and breakthrough curve slope were affected by the packing ratio of the two adsorbents.

• Resources Recycling
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• v.12 no.3
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• pp.13-24
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• 2003

The production characteristics of activated carbon from waste walnut shell have been investigated by taking activation temperature, activation time, amount of activating agent, and kind of activating agent as the major influential factors. The adsorption capacity of the activated carbon which was produced using phosphoric acid as the activating agent increased with activation temperature and showed its greatest value at about $550^{\circ}C$. Yield for activated carbon was observed to decrease continuously as the activation temperature was raised. The optimal activation time for the highest adsorption capacity was found to be about 2 hr, and as the activation time increased the yield for activated carbon was showed to decrease continuously. The increase in the amount of activating agent resulted in the increase of the yield for activated carbon, however, excessive amount of activating agent deteriorated its adsorption capacity reversely. The variations of the microstructure of activated carbon observed by SEM with several influential factors, correlated very well with its changes in the adsorbability with the same factors and the kind of activating agent was found to play an important role in the determination of the adsorption capacity of activated carbon. To investigate the adsorption characteristics of the produced activated carbon, the adsorption reactions of $Cu^{2+}$ ion were examined using the produced activated carbon as the adsorbent. In general, the kinetics of the adsorption of $Cu^{2+}$ ion was observed to follow a 2nd-order reaction and the rate constant for adsorption reaction increased as the initial concentration of adsorbate was diminished. The equilibrium adsorption of $Cu^{2+}$ was explained well with Freundlich model and its adsorption reaction was found to be endothermic. The activation energy for adsorption was calculated to be 13.07 kcal/mol, which implied that the adsorption reaction was very irreversible, and several thermodynamic parameters of adsorption reaction were estimated using van't. Hoff equation and thermodynamic relationships.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.24-30
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• 2002

The laboratory adsorption batch tests were performed to investigate the adsorption characteristics of Pb on kaolinite. The characteristics such as adsorption equilibrium time, adsorption capacity, adsorption isotherm were studied, and also the effects of pH and the mixing ratio on the adsorption of Pb on kaolinite were investigated. Test results show that the adsorption equilibrium state was reached within 24 hours, and the adsorbed amount of Pb increased, but the adsorption efficiency over the initial concentration of 198 mg/l decreased, with increasing the initial concentration of Pb. And the adsorption constant, 1/n was obtained 0.9584 by Freundlich isotherm equation. Regardless of the initial concentration of Pb. the adsorbed amount of Pb as well as the adsorption efficiency were increased with increasing pH values and converged to a certain constant value above 8 of pH values. And also the adsorbed amount of Pb increased with the mixing ratio, but its efficiency increased with the mixing ratio up to 8 and then showed the decreasing tendency above that.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.89-96
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• 2002

The adsorption characteristics of sodium chloride into Ca-alginate beads have been investigated and the result were as follows: Sodium chloride uptake by Ca-alginate beads increased with time. The highest uptake volume of sodium chloride was 4.2g after 10 minutes. The uptake volume by Fe, Ca, Ba, and Sr-alginate beads was 5.6g, 4.2g, 4.2g and 4.0g, respectively but in case of Fe-alginate beads, the induced hydrogel beads were very fragile and the strength of Fe-alginate beads were weaker than Ca- and Ba-alginate beads. Mg-alginate bead was not formed and Ca-, Ba- and Sr-alginate beads had a similar uptake volume about 4.2g, respectively. The uptake volume of sodium chloride by CaCl$_2$concentration(0.1M. 0.2M and 1M), curing solution, was 4.8, 4.2g and 4.1g, respectively. The uptake volume by sodium alginate concentration(0.6%, 1% and 2%) was 2.8g, 4.0g, and 4.4g, respectively and Ca-alginate bead size was not effected in uptake sodium chloride. The uptake rate on initial sodium chloride concentration(4%, 8%, 12% and 16%) was 30%, 28%, 27% and 25%, respectively. The uptake rate on basic pH(10.0) was higher than when compared to other neutral pH(6.8) and acidic pH(4.0). The initial uptake velocity of sodium chloride from immobilization beads with salt resistant bacteria was lower than that of non-immobilization beads. The uptake rate of sodium chloride was decreased according to elongation of curing time. Reusability of Ca-alginate beads was possible but according to reutilization, the salt uptake volume of beads was also decreased. The uptake volume of sodium chloride from Doengjang by Ca-alginate beads on time course(3, 6, 12, and 24 hour) was revealed 5g, 6g, 7g and 7g, respectively.

• Economic and Environmental Geology
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• v.36 no.5
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• pp.381-385
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• 2003

We investigated possible application of waste ferrite in treating Cd and Pb in wastewater. Adsorption of Cd and Pb on Mn-Ferrite are influenced by several controlling factors such as contact time, heavy metal concentrations, pH and temperature. Both Cd and Pb achieved adsorption equilibrium within 5 minutes. Based upon this kinetic data, 24 hours of contact time was allowed for other experiment. The adsorption of Cd and Pb was high at high pH and high ion concentrations. The reaction was also affected by temperature. Adsorption isotherms fits well with the Freundlich isotherm equation. pH is the main controlling factor in Cd, Pb adsorption on the Mn-ferrite. Cd showed S type adsorption curve while Pb showed sorption edges, depending on the Pb concentrations.