• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.664-672
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• 2010

This study was performed to evaluate the feasibility of industrial by-products such as converter slag, olivine, red mud and fly ash as a seed crystal of struvite crystallization for the removal of highly concentrated $NH_4-N$ and $PO_4-P$. In the kinetic experiments, more than 90% of $NH_4-N$ and $PO_4-P$ was eliminated by struvite crystallization within 30 minutes of reaction time. The pH range in meta-stable region of struvite crystallization was found to be pH 7.0~9.0 under the Mg:N:P=1:1:1 equi-molar condition with 100 mg/L of $NH_4-N$. Total removal efficiencies of $NH_4-N$ and $PO_4-P$ by both struvite precipitation and crystallization were increased with the increase of pH. Removal efficiencies of $NH_4-N$ and $PO_4-P$ were significantly enhanced by struvite crystallization using industrial by-products as a seed crystal compared with those by struvite precipitation without seed crystal. Red mud, converter slag, olivine and fly ash enhanced the removal efficiencies of $NH_4-N$ by 40.9%, 37.7%, 28.4% and 16.4%, respectively. Removal efficiencies of $PO_4-P$ for converter slag, red mud, fly ash, olivine were increased by 3.7 times, 2.6 times, 72.4% and 68.0%, respectively. Converter slag and red mud showed higher feasibility as a seed crystal than others for the removal of highly concentrated $NH_4-N$ and $PO_4-P$. In particular, converter slag might have a high capacity of phosphorus removal.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.17-22
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• 2010

The aim of this study is to research applicable possibility of DSI (Dry Sorbent Injection) technique in $SO_2$ removal process using lab-scale facility based on 500MW in capacity coal-fired thermal power plant operated by South Korea N. Power Co., Ltd. To increase the $SO_2$ removal efficiency, it is considered the mixing enhancement as different shapes called lobed-plate and stepplate tested ultimately for optimum shape. Also it tested to analysis $SO_2$ removal efficiency by numbers of injection holes. At experimental it showed the $SO_2$ removal efficiency is higher using mixing enhancement than not installed mixing enhancement and case on the step-plate was shown the most $SO_2$ removal efficiency. Also, $SO_2$ removal efficiency was higher recording which will increase the injection holes case on not installed mixing enhancement. But, the $SO_2$ removal efficiency was higher 4 injection holes case on installed mixing enhancement.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.344-349
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• 2001

The removal of chlorine from aqueous solutions on dried Chlorella vulgaris(DCV) and green tea powder(GTP) were investigated as a function of contact time, pH and initial chlorine concentration. Removal by DCV and GTP reached equilibrium after 3hrs and 0.5hr, respectively. Optimum removal pH values of DCV and GTP were determined as above 10. Both Langmuir and Freundlich adsorption models were suitable for describing the short-term removal of chlorine by DCV and GTP. According to Langmuir adsorption isotherms the maximum removal capacity of DCV (2.75mg $Cl_2/mg$) was nearly two times greater than those of GTP (1.53mg $Cl_2/mg$) and activated carbon (1.47mg $Cl_2/mg$). These results suggested that Chlorella vulgaris biomass might potentially be used as an alternative to traditional water treatment materials for removal of residual chlorine in drinking water or process waste-water.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.61-72
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• 1997

This research aims to remove the heavy metals, nonbiodegradable COD(NBDCOD), and color using the coal waste. The experimental by heat treatment was performed to advance the adsorption capacity. The results are as follows ; i) The coal waste had the adsorption capacity of heavy metals and the rates were in the range of 20 to 30 percents. ii) The heat treatment was the optimum condition that the reaction time was 6 hours at $500^{\circ}C$, , iii) In the column experimen, non-treated coal waste removed the COD and color in the range of 20 to 60 percents. iv) Heat-treated coal waste showed higher removal rate of the color in biological effluent, and heavy metal and COD removal rates were changed by the filteration rates.

• Nuclear Engineering and Technology
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• v.9 no.2
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• pp.75-81
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• 1977

This experiment has been carried out to determine the pH dependent cation exchange capacity concerning the sorption phenomenon of long-lived radionuclides contained in low-level liquid radioactive waste on various clay minerals. The pH dependent cation exchange capacity determined by Sawhney's method are used to the analysis of sorption phenomenon. About 70 percent of the total cation exchange capacity is contributed by the pH dependent CEC due to the negative charge originated naturally in clays in case of clinoptilolite, vermiculite and sodalite. It is sugested in this test that the high neutral salt CEC, that is, highly charged clays would show good fixation yield. The removal of radionuclides at the pH range more than pH 9 is considered the hydroxide precipitation of metal ion rather than the cation exchange. The Na-clay prepared by the method of successive isomorphic substitution with electrolyte showed a considerable improvement in removal efficiency for the decontamination.

• KSBB Journal
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• v.17 no.2
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• pp.115-120
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• 2002

Biofiltration is a bioprocess treating volatile organic compounds (VOCs) in order to convert the VOCs to harmless products. This review on biofiltration is intended to provide an engineering concept such as removal efficiency, maximum load, elimination capacity and so on. Besides, modeling concept of biofilter is also supplied for designing biofilter system. Quantitative data generated in our research group is shown to explain the engineering concept as well as the modeling idea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.941-946
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• 2012

Macrophyte plays an important role in purification of wastewater. They have capacity to improve the water quality by absorbing nutrients, with their effective root system. In this study, removal of nutrient as well as organic matter was observed by some important macrophytes i.e. Pistia stratoites, Hydrocharis dubia and Salvinia sp. indepe ndently as well as in mixed culture under the laboratory condition. The highest total nitrogen removal was observed for Pistia stratoites (86.47%) in monoculture and Salvinia sp. + P. stratoites (76.11%) in mixed culture system. Corresponding figures for total phosphorous were observed for P. stratoites (75.60%) in monoculture and Salvinia sp. + P. stratoites (71.11%) in mixed culture system. Similar result was observed for ammonia removal in both systems. Additionally, P. stratoites showed the highest removal of organic matter, in monoculture system (68.46%) where as Salvinia sp. + P. stratoites showed the highest removal of organic matter in mixed culture system (82.73 %).

• Environmental Engineering Research
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• v.17 no.3
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• pp.133-138
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• 2012

Polyvinyl alcohol/alginate hydrogel beads containing Mg-Al layered double hydroxide (LDH-PVA/alginate beads) were synthesized for phosphate removal. Results showed that blending PVA with the LDH-alginate beads significantly improved their stability in a phosphate solution. The kinetic reaction in LDH-PVA/alginate beads reached equilibrium at 12 hr-post reaction with 99.2% removal. The amount of phosphate removed at equilibrium ($q_e$) was determined to be 0.389 mgP/g. The equilibrium data were described well by the Freundlich isotherm with the distribution coefficient ($K_F$, 0.638) and the constant (n, 0.396). Phosphate removal in LDH-PVA/alginate beads was not sensitive to solution pH. Also, the removal capacity of LDH-PVA/alginate beads ($q_e$, 1.543 mgP/g) was two orders of magnitude greater than that of PVA/alginate beads ($q_e$, 0.016 mgP/g) in column experiments. This study demonstrates that LDH-PVA/alginate beads with a higher chemical stability against phosphate compared to LDH-alginate beads have the potential for phosphate removal as adsorptive media.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.5
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• pp.17-23
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• 2013

Six-valent chromium ($Cr^{6+}$) is a highly toxic pollutant, supplied in a variety of industrial activities such as leather tanning, cooling tower blowdown, and plating. Herein, we investigated the removal of $Cr^{6+}$ from aqueous phase using low-cost adsorbents. Steel slag, montmorillonite, illite, kaolinite, red mud, and acid treated red mud with 0.5, 1.0, and 2.0 M HCl were used as adsorbent for the removal of $Cr^{6+}$ and the results showed that acid treated red mud with 2.0 M HCl (ATRM-2.0 M) had higher adsorption capacity of $Cr^{6+}$ than other adsorbents used. Accordingly, $Cr^{6+}$ removal by ATRM-2.0 M were studied in a batch system with respect to changes in initial concentration of $Cr^{6+}$, initial solution pH, adsorbent dose, adsorbent mixture, and seawater. Equilibrium sorption data were described well by Freundlich isotherm model. The influence of initial solution pH on $Cr^{6+}$ adsorption was insignificant. The use of the ATRM-2.0 M alone was more effective than mixing it with other adsorbents including red mud, zeolite, oyster shell, lime stone, and montmorillonite for the removal of $Cr^{6+}$. The $Cr^{6+}$ removal of the ATRM-2.0 M was slightly less in seawater than deionized water, resulting from the presence of anions in seawater competing for the favorable adsorption site on the surface of ATRM-2.0 M. It was concluded that the ATRM-2.0 M can be used as a potential adsorbent for the removal of $Cr^{6+}$ from the aqueous solutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.380-384
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• 2007

The COD removal capacity of aquatic plants, when foamed glasses were not used, showed 56% for Pistia straiotes, 48% for Phragmites japonica and 41% for Oenanthe javanica, but no significant COD removal was observed for Lythrum anceps. When the foamed glasses were used as support materials, the COD removal efficiency increased for all aquatic plants used in this study showing 69% fur Pistia straiotes, 68% for Pharagmites japonica 62% for Oenanthe javanica, respectively. The T-N removal efficiency of aquatic plants when foamed glasses were used as support materials showed 91% for Lythrum anceps and 93% for Phragmites japonica. Similar removal efficiency was observed as 94% for all aquatic plants planted as a group used in this study. The T-P removal efficiency of aquatic plants when foamed glasses were not used showed 35% for Lythrum anceps, 8% for Phragmites japonica, however, that, when foamed glasses were used, ranged 78% for Lythrum anceps, 43% for Phragmites japonica, showing that the foamed glasses increase the T-P removal efficiency of aquatic plants used in this study.