• Journal of Korean Society on Water Environment
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• v.32 no.3
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• pp.303-309
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• 2016

This study aimed to assay the biological removal of TDS (total dissolved solids) from RO (reverse osmosis) rejected water. Following bio-sorption of TDS with AGS (aerobic granular sludge), the effects of TDS on biological nitrogen removal were examined. The bio-sorption of TDS after AGS treatment was confirmed by checking for TDS removal efficiency and surface analysis of microorganisms with SEM and EDS. Then, the effects of TDS on biological nitrogen removal and the denitrification efficiency were evaluated using the MBR reactor. According to the results, the bio-sorption of TDS with AGS was 0.1 mg TDS/mg AGS, and we confirmed that the microorganism surfaces had adsorbed the TDS. Biological nitrogen removal efficiency was measured at inhibiting denitrification at 4,000 mg/L of TDS-injected material. Based on this study, it is necessary to pretreat TDS-containing RO rejected water and to maintain TDS concentration lower than a specific value (≤4,000 mg/L), when considering biological nitrogen removal.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.66-74
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• 2016

Environmental pollution from abandoned metal mines has been awarded as serious problem and many techniques have been applied to remediate pollutants. Main objective of this research was to evaluate efficiency of heavy metal sorption capacity of spent mushroom media (SMM) in aqueous and soil matrix. Laboratory batch experiment was conducted and 4 different heavy metals (Cd, Pb, Cu, Zn) were evaluated. In aqueous phase, all 4 heavy metals showed high reduction efficiency ranged from 60-99% and Pb showed the highest sorption efficiency. In case of soil phase, much lower sorption efficiency was observed compared to aqueous phase. The highest reduction efficiency was observed in Cd (average of 38%). With scanning electron microscopy energy dispersive detector (SED-EDS) analysis, we confirmed sorption of heavy metals at the surface of SMM. Overall, SMM can be used as sorption materials for heavy metals in both aqueous and soil matrix and more research should be conducted to increase sorption efficiency of SMM in soil.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.377-382
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• 2014

Micro-/macroporous carbons (MMCs) were prepared using a hollow mesoporous silica capsule (HMSC) as a sacrificial hard template. The carbonization process after the infiltration of furfuryl alcohol into the template-free HMSC material afforded MMC materials in high yield. The hard template HMSC could be removed by HF etching without deteriorating the structure of MMC. The MMC materials were fully characterized by SEM, TEM, PXRD, XPS, and Raman spectroscopy. The replication processes were so successful that MMCs exhibited a hollow capsular structure with multimodal microporosity. Detailed textural properties of MMC materials were investigated by volumetric $N_2$ adsorption-desorption analysis at 77 K. To explore the gas sorption abilities of MMCs for other gases, $H_2$ and $CO_2$ sorption analyses were also performed at various temperatures. The multimodal MMC materials were found to be good sorbents for both $H_2$ and $CO_2$ at low pressure.

• Economic and Environmental Geology
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• v.43 no.6
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• pp.555-564
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• 2010

Remediation process by using the bio-carrier (beads) with dead Bacillus sp. B1 and polysulfone was investigated for heavy metal contaminated groundwater. Sorption batch experiments using the bio-carrier were performed to quantify the heavy metal removal efficiencies from the contaminated solution. The analyses using SEM/EDS and TEM for the structure and the characteristic of precipitates on/inside the beads were also conducted to understand the sorption mechanism by the bio-carrier. Various amounts of freeze-dried dead Bacillus sp. B1 were mixed with polysulfone + DMF(N,N-dimethylformamide) solution to produce the bio-carrier (beads; less than 2mm in diameter) and 5% of Bacillus sp. B1 in the bio-carrier was optimal for Pb removal in the solution. The removal efficiency ratings of the bio-carrier for Pb, Cu and Cd were greater than 80% after adding 2g of bio-carrier in 50ml of aqueous solution (<10mg/L of each heavy metal concentration). Reaction time of the bio-carrier was very fast and most of the sorption reaction for heavy metals were completed within few hours. Batch experiments were duplicated at various pH conditions of aqueous solutions and Cu and Pb removal efficiencies highly maintained at wide pH ranges (pH 2-12), suggesting that the bio-carrier can be useful to clean up the acidic waste water such as AMD. From SEM/EDS and TEM analyses, it was observed that the bio-carrier was spherical shape and was overlapped by many porous layers. During the sorption experiment, Pb was crystallized on the surface of porous layers and also was mainly concentrated at the boundary of Bacillus sp. B1 stroma and polysulfone substrate, showing that the main mechanism of the bio-carrier to remove heavy metals is the sorption on/inside of the bio-carriers and the bio-carriers are excellent biosorbents for the removal of heavy metal ions from groundwater.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3507-3508
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• 2010

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.4
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• pp.386-395
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• 2002

This study would like to measure and compare water sorption and solubility of acrylic resins, with 3 different polymerizing methods, and tensile strength between denture base resin and relining rosins. For this experiment, 3 different acrylic resins were used; heat polymerizing resin: Vertex (Dentmex, Zeist, Holland), autopolymerizing resin: Tokuso Rebase (Tokuyama Corp, Tokyo, Japan), and light curing resin: Mild Rebaron LC(GC Corp, Tokyo, Japan) The results were as follows ; 1. Tokuso Rebase showed the lowest water sorption. followed by Mild Rebaron LC and Vertex. Among resins, there were some signigicant differences (P<0.05). 2. Vertex showed the lowest solubility, followed by Mild Rebaron LC and Tokuso Rcbase. Among resins, there were some signigicant differences (P<0.05). 3. Intact Vertex showed the highest tensile strength, and Mild Rebaron LC had a more tensile strength than Tokuso Rebase. Between Vertex and the other resins, there were some signigicant differences (P<0.05) However, between Mild Rebaron LC and Tokuso Rebase, there was no statistical difference (P>0.05). About 50% of Rebaron LC showed cohesive fracture. 4. Tensile strength has more decreased after thermocycling than before, but there was no statistical difference (P>0.05).

• Membrane and Water Treatment
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• v.8 no.1
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• pp.73-88
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• 2017

Adsorption kinetics of aqueous ferric ion ($Fe^{3+}$) onto bio-natural rice grains (BRG) have been studied in a batch system. The influence of contact time (0-180 minutes), the dosage of BRG adsorbent (10, 20, 40, and $60gL^{-1}$), and ambient temperature (27, 37, 47, and $57^{\circ}C$) for the adsorption system have been reported. The equilibrium time achieved after 20 minutes of adsorption contact time. The maximum removal of ferric ion is 99% by using $60gL^{-1}$ of BRG, $T=37^{\circ}C$, and $50mgL^{-1}$ ferric ion solution. Adsorption kinetic and diffusion models, such as pseudo-first order, pseudo-second order, and Weber-Morris intra-particle diffusion model, have been used to describe the adsorption rate and mechanism of the ferric ion onto BRG surface. The sorption data results are fitted by Lagergren pseudo-second order model ($R^2=1.0$). The kinetic parameters, rate constant, and sorption capacities have been calculated. The new information in this study suggests that BRG could adsorb ferric ion from water physiosorption during the first 5 minutes. Afterward, the electrostatic interaction between ferric ion and BGR-surface could take place as a very weak chemisorptions process. Thus, there is no significant change could be noticed in the FTIR spectra after adsorption. I recommend producing BGR as a bio-natural filtering material for removing the ferric ion from water.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.936-942
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• 2012

This review was to elucidate the fate of Bentazon(3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) and its metabolites in soil. Bentazon is rapidly degraded to form polar metabolites which are mostly adsorbed to soil components, such as humin or fulvic acid, as non extractable forms and mineralized into $CO_2$ by light or micro-organisms in both aerobic or nonaerobic condition. The degradation of Bentazon is dependent on the rate of organic matters in soil and the use of land for the tillage. The degradation rate is decreased as the amount of organic matters in soil increases and if the land is under use for tillage. Sorption and mobility of Bentazon depends on soil pH and the content of organic matters in soil. Usually, the sorption of the metabolites of Bentazon is decreased with increase in the mobility and pH. Almost all of Bentazon is degraded within rhizosphere or forms conjugate bonds with soil organic matters before it reaches to the ground water.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.666-670
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• 2015

Competition among anion species in solution for same sorption sites and soil surface can be of major significance in determining the effective mobility of any potentially adsorbing species. Major soil anion species include $OH^-$, $F^-$, $Cl^-$, $HCO_3{^-}$, $CO_3{^-}$, $NO_3{^-}$, $SO_4{^{2-}}$, and $PO_4{^{3-}}$. And some micro nutrients such as boron and molybdenum exist as $H_2BO_3{^-}$ and $MoO_4{^{2-}}$, as do some heavy metals such as chrome and arsenic as $CrO_4{^{2-}}$ and $HAsO_4{^{2-}}$. Pesticides such as 2,4,5-T and 2,4-D also exist as anions. Many anion species are retained by more complex mechanisms than the simple electrostatic attractions involved in most cation adsorption reactions. In binary system composed of two anions, the adsorption of one anion is influenced by the other anion due to the competition for the available and limited binding sites in soil constituents. The specifically adsorbed anions may compete more effectively for sorption sites than that of nonspecifically adsorbed anion. In this study, we aim to evaluate the mathematical models to determine the magnitude of concentration variations in adsorption due to competitive interactions between anions introduced to a system in binary mixtures.

• The Journal of Advanced Prosthodontics
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• v.7 no.4
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• pp.278-287
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• 2015

PURPOSE. The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. RESULTS. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. CONCLUSION. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.