• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.401-408
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• 2008

Adsorption performance of sulfonamide antibiotic compounds such as sulfadimethoxine(SDM), sulfachloropyridazine(SCP), sulfamethazine(SMT), sulfathiazole(STZ) and sulfamethoxazole(SMX) on granular activated carbon(GAC) was evaluated in this study. The coal-based activated carbon was found to be more effective than other carbons in adsorption of sulfonamide antibiotic compounds. The wood-based activated carbon was less effective than coconut- and coal-based carbon in adsorption nevertheless having larger pore volume and specific surface area than others carbons. The maximum adsorption capacities(X/M) of coal-based activated carbon for the five sulfonamide species was 1.3$\sim$1.5 and 1.8$\sim$2.1 times larger than coconut- and wood-based activated carbon, respectively. Carbon usage rates (CUR) of coal-, coconut- and wood-based activated carbons for SCP were 3.55 g/day, 4.29 g/day and 6.47 g/day, respectively. Similar results were obtained in the adsorption of the rest four sulfonamide species. It is concluded that coal-based activated carbon could removed the sulfonamide antibiotic compounds better than other material-based activated carbons.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.925-932
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• 2008

Adsorption performance of tetracycline antibiotic compounds such as tetracycline(TC), oxytetracycline(OTC), chlortetracycline (CTC) and minocycline(MNC) on granular activated carbon(GAC) was evaluated in this study. The coal-based activated carbon was found to be more effective than other carbons in adsorption of tetracycline antibiotic compounds. The wood-based activated carbon was less effective than coconut- and coal-based carbon in adsorption nevertheless having larger pore volume and specific surface area than others carbons. The maximum adsorption capacities(X/M) of coal-based activated carbon for the four tetracycline species was 1.27$\sim$1.36 and 1.69$\sim$1.84 times larger than coconut- and wood-based activated carbon, respectively. Carbon usage rates(CUR) of coal-, coconut- and wood-based activated carbons for tetracycline(TC) were 2.96 g/day, 3.40 g/day and 4.53 g/day, respectively. Similar results were obtained in the adsorption of the rest three tetracycline species. It is concluded that coal-based activated carbon could removed the tetracycline antibiotic compounds better than other material-based activated carbons.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.27-35
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• 2002

Characteristics of Amberlite IRN 77, a cation exchange resin, and the mechanisms of its adsorption equilibria with Co(II), Ni(II), Cr(III) and Fe(III) ions were investigated for the application of the demineralizing process in the primary coolant system of a pressurized water reactor (PWR). The optimum dosage of the resin for removal of the dissolved metal ions at $200mgL^{-1}$ was 0.6 g for 100 mL solution. Most of each metal ion was adsorbed onto the resin in an hour from the start of the reaction. Each metal adsorption onto the resin could be well represented by Langmuir isotherms. However, in the case of Fe(III) adsorption, continuous formation of Fe-oxide or -hydroxide and its subsequent precipitation inhibited the completion of the equilibrium between the metal and the adsorbent Cobalt(II) and Ni(II), which have an equivalent electrovalence, were adsorbed to the resin with a similar adsorption amount when they coexisted in the solution. However, Cr(III) added to the solution competitively replaced Co(II) and Ni(II) which were already adsorbed onto the resin, resulting in desorption of these metals into the solution. The result was likely due to a higher adsorption affinity of Cr(III) than Co(II) and Ni(II). This implies that the interactively competitive adsorption of multi-cations onto the resin should be fully considered for an efficient operation of the demineralizing ion exchange process in the primary coolant system.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.337-343
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• 2007

The reforming catalyst and the electrodes in fuel cells can be poisoned by the organic sulfur compound which is added as an odorant for checking out the leakage of natural gas, and that makes a big problem of system degradation. In this study, various adsorbents, such as silica, ${\gamma}$-alumina, activated carbon, HZSM-5, Ultra-stable Y zeolite (USY), and beta zeolite (BEA), were utilized to remove tetra-hydrothiophene (THT) and tert-butylmercaptan (TBM), and to confirm the performance in the adsorption of those odorants by using a continuous adsorptive bed. The effects of Si/Al ratio of zeolites, adsorption temperature and the type of balance gas (methane or He) on the adsorption performance in the packed bed have been investigated. In addition, the competitive adsorption between TBM and THT on the adsorbents was also estimated. The result shows that H-type BEA zeolite exhibited the highest adsorption capacity for TBM and THT odorant, and the higher amount of THT was removed adsorptively on the same adsorbent than TBM. The physical and chemical adsorption of those compounds on acid sites of zeolite were confirmed by temperature programmed desorption (TPD) and infrared spectrum (IR) analyses.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.65-75
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• 2017

C-S-H phase is the most abundant reaction product, occupying about 50~60% of cement paste volume. The phase is also responsible for most of engineering properties of cement paste. This is not because it is intrinsically strong or stable, but because it forms a continuous layer that binds together the original cement particles into a cohesive whole. The binding ability of C-S-H phase arises from its nanometer-level structure. In terms of chloride penetration in concrete, C-S-H phase is known to adsorb chloride ions, however, its mechanism is very complicated and still not clear. The purpose of this study is to examine the interaction between chloride ions and C-S-H phase with various Ca/Si ratios and identify the adsorption mechanism. C-S-H phase can absorb chloride ions with 3 steps. In the C-S-H phase with low Ca/Si ratios, momentary physical adsorption could not be expected. Physical adsorption is strongly dependent on electro-kinetic interaction between surface area of C-S-H phase and chloride ions. For C-S-H phase with high Ca/Si ratio, electrical kinetic interaction was strongly activated and the amount of surface complexation increased. However, chemical adsorption could not be activated for C-S-H phase with high Ca/Si ratio. The reason can be explained in such a speculation that chloride ions cannot be penetrated and adsorbed chemically. Thus, the maximum chloride adsorption capacity was obtained from the C-S-H phase with a 1.50 Ca/Si ratio.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1192-1197
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• 2006

Adsorbability of ionic and nonionic pharmaceuticals was studied using granular activated carbon(GAC). In a batch adsorption test of muticomponent solution, 500 mg/L of GAC dose removed all target compounds between 94 and 98% at initial concentration of 10 ${\mu}g/L$. Adsorption of ionic pharmaceuticals increased as pH was lowered toward to pKa, however adsorption capacity of nonionic pharmaceuticals showed insignificant variation with the changing pH. The enhanced adsorption capacity of ionic pharmaceuticals at lower pH was attributed to the corresponding increase in the molecular form of ionic pharmaceuticals with carboxylic group at low pH. In addition, decrease of pH increased hydrogen ion concentration in the bulk solution and the protons bound to the available sites on the carbon enhanced the removal of the ionic pharmaceuticals from solution. After 40 days of continuous operation, GAC column showed the removal of target compounds were removed by $93{\sim}99%$ at 15 min of EBCT mainly due to adsorption mechanism of GAC. At shorter EBCT than 15 min, breakthrough of CA, IBP and GFZ occurred earlier than the other ionic and nonionic pharmaceuticals. effect of EBCT on adsorption of nonionic pharmaceuticals was greater than ionic ones. This study showed that persitent pharmaceuticals found in drinking water treatment could be effectively controlled by adsorption in GAC process.

• Membrane Journal
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• v.17 no.3
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• pp.210-218
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• 2007

CEDI-BPM(Continuous Electrodeionization-Bipolar Membrane) has advantages due to high ion permselectivity through ion exchange membranes and the production of $H^+$ and $OH^-$ ions on the bipolar membrane surfaces for regeneration of ion exchange resin during electrodeionization operation. In this study, hardness materials were removed by the CEDI-BPM without scale formation and the ion exchange resins were electrically regenerated during the operation. The adsorption characteristic of ion exchange resin surface, the influence of flow rate on the hardness removal and electric regeneration were investigated in the study. The removal efficiency of Ca was higher than that of Mg in the CEDI-BPM, which was related to the high adsorption capacity of Ca on the cation exchange resin. With increasing flow rate, the flux of Ca and Mg was enhanced by the permselectivity of a cation exchange membrane. In the electric regeneration of CEDI-BPM, it was shown that the regeneration efficiency was higher with a lower regeneration potential applied between cathode and anode.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.28-36
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• 2018

Adsorption experiments of three target gases such as acetone, benzene, and methyl mercaptan (MM) were carried in a continuous reactor using the activated carbon prepared from waste citrus peel. In a single gas system, the breakthrough time obtained from using the activated carbon (WCAC) prepared from waste citrus peel. In a single gas system, the breakthrough time obtained from the breakthrough curve decreased with increasing the inlet concentration and flow rate, but increased with respect to the aspect ratio (L/D). Adsorbed amounts of the target gases by WCAC increased as a function of the inlet concentration and aspect ratio. However, adsorbed amounts with the increase of the flow rate were different depending upon target gases. Results from the breakthrough time and adsorbed amount showed that the affinity for WCAC was the highest in benzene, followed by acetone and then MM. On the other hand, in the binary and ternary systems, the breakthrough curve showed a roll-up phenomenon where the adsorbate having a small affinity for WCAC was replaced with the adsorbate with a high affinity. The adsorption of acetone on WCAC was more strongly affected when mixing with the nonpolar benzene than that of using sulfur compound MM.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.594-603
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• 2018

The effects of operating conditions such as benzene concentration, nitrogen flow rate, steam flow rate, and bed temperature on TSA process were experimentally investigated as a potential VOC removal technology using two kinds of beds packed with activated carbon and zeolite 13X. The TSA cycle studied was composed of the adsorption step, steam desorption step, and drying and cooling step. At 2% benzene concentration, the total adsorption amounts of zeolite 13X and activated carbon were 4.44 g and 3.65 g, respectively. Since the zeolite 13X has a larger packing density than that of the activated carbon, the larger benzene amount could be adsorbed in a single cycle. Increasing the water vapor flow rate to 75 g/hr at 2% benzene concentration reduced the desorption time from 1 hr to a maximum of 33 min. If the desorption time is shortened, the drying and cooling step period can be relatively increased. Accordingly, the steam removal and bed cooling could be sufficiently performed. The desorption amounts increased with the increase of the bed temperature. However, the energy consumption increased while the desorption amount was almost constant above $150^{\circ}C$. In the continuous cycle process, when the amount of remained benzene at the completion of the regeneration step increased, it might cause a decrease in the working capacity of the adsorbent. The continuous cycle process experiment for zeolite 13X showed that the amount of remained benzene at the end of regeneration step maintained a constant value after the fourth cycle.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.51-57
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• 1999

Adsorption characteristics of Ni(II), Co(II) and Ag(I) ions on the Amberite IRN 77 cation exchange resin have been studied to suggest the guide-line for the optimum operation of demineralization process in primary coolant system during the shut-down period of pressurized water reactor(PWR). The adsorption mechanism of each metal ion, Ni(II), Co(II) or Ag(I) ion, on a cation exchange resin was well coincided with Langmuir isotherm. The adsorption and treatment capacities of $H^+$-form resin were higher than those of $Li^+$-form resin. In the continuous ion exchange process for the solution of multi-component system, the selectivity of the resin was in increasing order of Ni(II)${\approx}$Co(II)>Ag(I). In addition, the increase of the flow rate decreased the treatment capacity of the resin as well as the slope of the breakthrough curve.