• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.501-502
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• 2004

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.407-414
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• 2015

The effect of activated carbon particle diameter (i.e. US sieve No. $8{\times}10$ ($d_p{\approx}2.19mm$), $18{\times}20$ ($d_p{\approx}0.92mm$), $50{\times}60$ ($d_p{\approx}0.27mm$) and $170{\times}200$ ($d_p{\approx}0.081mm$) on caffeine adsorption is investigated. BET surface area was increased with decreasing particle diameter ($d_p$), and caffeine adsorption rates increased with decreasing $d_p$. Moreover, pseudo-second order model is predicted the experimental data more accurately than pseudo-first order model, and the fastest rate constant ($k_2$) was $1.7g\;mg^{-1}min^{-1}$ when $d_p$ was 0.081 mm. Surface diffusion coefficient (Ds) was decreased with decreasing $d_p$ based on the minimum sum of square error (SSE). Practically, certain ranges of Ds are acceptable with high reliability ($R^2$) and it is determined that the effect of $d_p$ on Ds is unclear. The effect of pH on caffeine adsorption indicated the dependency of m/L ratio (mass liquid ratio) and $pH_{pzc}$. The $pH_{pzc}$ (i.e. $7.9{\pm}0.2$) was not affected by $d_p$. The higher caffeine adsorption at pH 4 and pH 7 than at pH 10 is due to $pH_{pzc}$, not $pk_a$ of caffeine.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1678-1683
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• 2003

DBD(Dielectric Barrier Discharge) plasma in air is well established for the production of large quantities of ozone and is more recently being applied to aftertreatment processes for HAPs(Hazardous Air Pollutants). Although DBD high electron density and energy, its potential use as nano and sub-micron sized particle charging are not well known. Aim of this work is to determine design and operating parameters of a two-stage ESP with DBD. DBD and ESP are used as particle charger and precipitator, respectively. We measured particle precipitation efficiency of two-stage ESP and estimated ozone decomposition of both pelletized $MnO_2$ catalyst and pelletized activated carbon. To examine the particle precipitation efficiency, nano and sub-micron sized particles were generated by a tube furnace and an atomizer. AC voltage of $7{\sim}10$ kV(rms) and 60 Hz is used as DBD plasma source. DC -8 kV is applied to the ESP for particle precipitation. The overall particle collection efficiency for the two-stage ESP with DBD is over 85 % under 0.64 m/s face velocity. Ozone decomposition efficiency with pelletized $MnO_2$ catalyst or pelletized activated carbon packed bed is over 90 % when the face velocity is under 0.4 m/s in dry air.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.798-806
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• 2017

A activated carbon (WCAC, waste citrus activated carbon) prepared from an agricultural waste citrus peel material generated in Jeju was utilized for the removal of dimetridazole (DMZ) antibiotics in aqueous solution. The adsorption of DMZ on WCAC was investigated with the change of various parameters such as contact time, dosage of WCAC, particle size of WCAC, temperature, pH, and DMZ concentration. The DMZ adsorption capacity increased with increasing temperature and decreasing particle size. Also it was decreased at less than pH 4 but sustained almost constantly at pH 4 or greater. Isotherm parameters were determined from the Langmuir, Freundlich, Redlich-Peterson and Duinin-Radushkevich (D-R) isotherm models. The isotherm data were best described by the Redlich-Peterson isotherm model. And the adsorption kinetics can be successfully fitted to the pseudo-second-order kinetic model. The results of the intra-particle diffusion model suggested that film diffusion and intra-particle diffusion were occurred simultaneously during the adsorption process. Meanwhile, the thermodynamic parameters indicated that the adsorption reaction of DMZ on WCAC was an endothermic and spontaneous process. The experimental results showed that WCAC is a promising and cheap adsorbent for the removal of DMZ antibiotics.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.1-11
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• 2008

Phenanthrene uptake by surfactant sorbed on activated carbon was investigated to recycle of surfactant in washed solution for contaminated soil. The partitioning of phenanthrene to the activated carbon coating with Triton X-100 as a surfactant was also evaluated by a mathematical model. Phenanthrene-contaminated soil (200 mg/kg) was washed in 10 g/L of surfactant solution. Washed phenanthrene in solution was separated by various particle loadings of granular activated carbon through a mode of selective adsorption. Removal of phenanthrene was 99.3%, and surfactant recovery was 88.9% by 2.5 g/L of granular activated carbon, respectively. Phenanthrene uptake by activated carbon was greater than that of phenanthrene calculated by a standard model for a system with one partitioning component. This is accounted for enhanced surface solubilization by hemi-micelles adsorbed onto granular activated carbon. The effectiveness factor is greater than 1 and molar ratio of solubilization to sorbed surfactant is higher than that of liquid surfactant. Results suggest that separation of contaminants and surfactants by activated carbon through washing process in soil is much effective than that of calculated in a theoretical model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.157-164
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• 2021

Recently, a number of studies have been conducted on photocatalysts and adsorbents that can remove harmful substances to improve environmental problems related to fine particles. In this study, a porous foam composites were fabricated using palm-based activated carbon having a large amount of micro-pores and foam concrete with a significantly larger total pore volume compared to general construction materials. To evaluate the adsorption potential of fine particles, the pore structure of the foam composites were analyzed. For the analysis of the pore structure of the foam composite, BET and Harkins-jura theory were applied from the measured nitrogen adsorption isotherm. From the results of the analysis, the specific surface area and micro-pore volume of the foam composite containing activated carbon increased significantly compared to Plain. As thereplacement of activated carbon increased, the specific surface area and micro-pore volume of the foam composite tended to increase. It seems that the foam composite has high adsorption performance for gaseous fine particle precursor such as nitrogen oxides.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.102-109
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• 2012

In this study, the four different filter media (sponge, volcanic stone, activated carbon and magnesium hydroxide) were tested for the removal of algae and phosphorus in the two eutrophic water samples (natural water and artificial algal culture with BG-11 medium). These filter media were used in the column device as single or combined applications. The effect of the $Mg(OH)_2$ on phosphorus removal was examined using different particle sizes (<2 mm and >2 mm) and concentrations (0, 10, 50 and 100 g $L^{-1}$) of magnesium hydroxide. The removal efficiency of phosphate by magnesium hydroxide was increased with longer experimental time and higher concentration. However, there was no significant difference in the degree of phosphorus removal between any two particle sizes (1 mg P $L^{-1}$: F=0.109, P=0.685; 10 mg P $L^{-1}$: F=1.542, P=0.355). Among the four media, activated carbon showed the most potent effect on the removal of both algae and phosphorus. The highest removal efficiency of algae and phosphorus was obtained by combining four columns of each filter medium. Interestingly, integration of four filter columns showed higher removal efficiency than activated carbon alone. The highest removal efficiency by integrated filter columns seemed to be caused by a synergistic effect of combined activated carbon and magnesium hydroxide.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.619-627
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• 2004

Purposes of this study were to examine closely the extracellular polymeric substances (EPS) which was a membrane fouling contaminant, to control detected EPS by powdered activated carbon (PAC) dosage etc. and to evaluate the possibility of practical reuse facility. With high removal efficiency of general pollutants, when the PAC is added to MBR, improvement of removal efficiency of $COD_{cr}$, and color was expected and treated wastewater can be reused. It was judged that the correlation between EPS and membrane fouling was very high. Carbohydrate and DNA in the EPS were judged to be cause of membrane fouling. If EPS could be controled, not only membrane fouling would be decreased but also operation time would be extended. In experiment of powdered activated carbon (PAC), characteristics of the best PAC for membrane fouling control were the particle size of $7{\mu}m$, lodine Number of 1,050, surface area of peat of $1,150m^2/g$. In lab test, operation time of MBR by PAC dosage of 200mg/gVSS was longer than one of MBR by without PAC dosage. Because EPS, especially carbohydrate and DNA, was controled successfully by PAC, membrane fouling in MBR could be decreased.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.396-399
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• 2007

In present work, the anti-bacterial effect of silver/activated carbon (Ag/C) composites prepared by the ${\gamma}$-irradiation of $AgNO_3$ solution on Escherichia coli (E. coli) has been studied. Characteristics of the Ag/C composites were identified by scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption spectroscopy (AAS). The inhibitory concentration of E. coli was found to be 0.387 ppm and the sterilizing concentration for the tested organism was 1.017 ppm. These results support the evidence that Ag/C composites have strong antibacterial activity to E. coli.

• Journal of Electrochemical Science and Technology
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• v.1 no.1
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• pp.63-68
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• 2010

The $Li_4Ti_5O_{12}$/AC composite was prepared by sol-gel process with ultrasonication. The prepared composite was characterized by SEM, XRD and TG analysis, and their electrochemical behaviors were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge test in 1M $LiBF_4$/PC electrolyte. From the results, the $Li_4Ti_5O_{12}$ particles coated on AC surface had an average particle size of 100 nm and showed spinel-framework structure. When the potential range of the $Li_4Ti_5O_{12}$/AC composite was extended from 0.1 to 2.5 V, redox peaks and electric double layer property were revealed. The initial discharge capacity of $Li_4Ti_5O_{12}$/AC composite was 218 mAh $g^{-1}$ at 1 C. The enhancement of discharge capacity was attributed to electric double layer of added activated carbon.