• Journal of Environmental Science International
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• v.2 no.4
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• pp.357-365
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• 1993

This study was conducted for the efficient utilization of biomaterials such as starch residue, tangerine skin, and green tea residue, which are agricultral by-products discarded in Cheju Province annually, as adsorbents and biomaterials were examined for their removal ability of heavy metal ions in waste water by batch adsorption experiments. The removal efficiency of biomaterials for heavy metal ions was above 80-90% and almost similar to activated carbon and the adsorption ability of those treated with 포르말린 was improved in the green tea residue only for $Pb^{2+}$, $Cu^{2+}$, and $Zn^{2+}$. In the conditions of pH, the removal efficiency of heavy metal ions was high in the range of 5-7. In the solutions which heavy metal ions were mixed, the removal efficiency was similar at $Ag^+$, $Pb^{+2}$ and reduced to about 10% at the other ions, as compared with the solutions they were not mixed. Adsorption isotherm of biomaterials was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, 1/n were obtained in the range of 0.1-0.5.

• Journal of Conservation Science
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• v.30 no.2
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• pp.235-241
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• 2014

In this study, we are trying to verify humidity control capability of the exhibition environment of cultural property by measuring adsorption and desorption performance, the control ability of harmful substances by the adsorption experiments of harmful gases. In the experiment of adsorption and desorption performance, in the low humidity area, Artsorb desorbed overwhelmingly more than activated carbon whereas activated carbon absorbed more. Adsorption speed was faster slightly in Artsorb absorption speed was similar in both. In the middle humidity area, absorption by artsorb was slightly more and desorption was similar in both so characteristic of Artsorb didn't appear. Also, Adsorption speed was faster in activated carbon but in the process of desorption, the speed of Artsorb was faster. In adsorption experiment of harmful substances, the concentration in the environment with activated carbon was lower than one with Artsorb, but the difference appeared small. And as a result of observation of the difference in concentration due to adsorption of harmful gas by the change in the metal specimen, the most change was shown in lead specimen and the color difference between the lead specimens of the activated carbon and Artsorb appeared greatly.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.858-863
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• 2020

We experimented with the particle-settling velocity and CHCl3 absorption efficiency of seven activated-carbon and analyzed seven heavy metal contents by elution for application to the field treatment of sunken HNS on the marine seabed. The mean particle-settling velocity was in the range 0.5-8 cm/s, except when the 8-20 mesh was used. The larger the HNS particle, the faster the particle-settling velocity was, and the CHCl3 absorption efficiency increased considerably owing to the larger surface area. In addition, the elution test results showed that the total Zn and As contents in >100-meshed activated carbon was higher than the contents criteria for the standard for water-treatment agents, and Cr, Zn, and As were released at higher concentrations than those released by other activated-carbon groups. Taken together, the CHCl3 absorption efficiency, settling velocity, and elution test results suggested that the 20-60, 20-40, and 2mm&down mesh activated-carbon adsorbents could be applied to the field treatment of HNSs and that the minimum required amount for field treatment were 0.82, 0.90, and 1.28 ton/㎘, respectively, as calculated based on the HNS-adsorption-capacity priority.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.99-113
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• 2016

In order to improve the portability of basic absorbents monoethanolamine (MEA) and glycine (Gly), both were supported on microporous activated carbon (AC). Chemical modification by alkali-metal ion exchange (of Li, Na, K) was carried out on Gly-based absorbents. All supported absorbents were subjected to $CO_2$ absorption capacity (pure $CO_2$) and selectivity (indoor level) tests. Textural and chemical characterizations were carried out on test sorbents. All impregnation brought about significant reduction of specific surface area and microporosity of the adsorbent Depreciation in the textural properties was found to result to reduction in pure $CO_2$ sorption. Contrarily, low-level $CO_2$ removal capacity was enhanced as the absorbent dosage increases, resulting in supported 5 molar MEA in methanol solution. Adsorption capacities were improved from 0.016 and 0.8 in raw ACs to 1.065 mmol/g for MEA's. Surface chemistry via X-ray photoelectron spectroscopy (XPS) of the supported sorbents showed the presence of amine, pyrrole and quaternary-N. In reducing sequence of potency, pyridine, amine and pyrrolic-N were noticed to contribute significantly to $CO_2$ selective adsorption. Furthermore, the adsorption isotherm study confirms the presence of various SNGs heterogeneously distributed on AC. The adsorption mechanism of the present AC adsorbents favored Freundlich and Langmuir isotherm at lower and higher $CO_2$ concentrations respectively.

• Carbon letters
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• v.5 no.4
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• pp.180-185
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• 2004

Thermolysis of $Cu(NO_3)_2{\cdot}3H_2O$ impregnated activated carbon fiber (ACF) was studied by means of XRD analysis to obtain Cu-impregnated ACF. $Cu(NO_3)_2{\cdot}3H_2O$ was converted into $Cu_2O$ around $230^{\circ}C$. The $Cu_2O$ was reduced to Cu at $400^{\circ}C$, resulting in ACF-C(Cu). Some Cu particles have a tendency to aggregate through the heat treatment, resulting in the ununiform distribution in ACF. Catalytic decomposition of NO gas has been performed by Cu-impregnated ACF in a column reactor at $400^{\circ}C$. Initial NO concentration was 1300 ppm diluted in helium gas. NO gas was effectively decomposed by 5~10 wt% Cu-impregnated ACF at $400^{\circ}C$. The concentration of NO was maintained less than 200 ppm for 6 hours in this system. The ACF-C(Cu) deoxidized NO to $N_2$ and was reduced to ACF-$C(Cu_2O)$ in the initial stage. The ACF-$C(Cu_2O)$ also deoxidized NO to $N_2$ and reduced to ACF-C(CuO). This ACF-C(CuO) was converted again into ACF-C(Cu) by heating. There was no consumption of ACF in mass during thermolysis and catalytic decomposition of NO to $N_2$ by copper. The catalytic decomposition was accelerated with increase of the reaction temperature.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.673-678
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• 2010

In the present study, mixed carbon-supported platinum(Pt) nanoparticles were prepared by a chemical reduction method of Pt precursor solution on two types of carbon materials such as activated carbons(ACs) and graphite nanofibers(GNFs). Average crystalline sizes and loading levels of Pt metal particles could be controlled by changing a content of GNFs. The highest electroactivity for methanol oxidation was obtained by preparing the carbon supports having 15 wt% GNFs. Furthermore, with an increase of GNFs content from 0% to 15%, an electrical conductivity was changed from $10^{-4}S/cm$ to $10^{-1}S/cm$. By an introduction of 10 wt% GNFs additive, the electroactivity of platinum particles was enhanced, but was saturated in the case of 15 wt% GNFs contents. This was related with the fact that the electroactivity change was dependent on the electrical conductivity of mixed carbon supports and Pt particle deposition content or deposition morphology.

• Environmental Engineering Research
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• v.18 no.4
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• pp.229-234
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• 2013

This study aimed to develop a new dust collecting system equipped with an activated carbon (A.C.) coated electrode. Before fabrication, pre-treatment of A.C. was performed to remove metal ions within the A.C. to enlarge its specific surface area. Then, pre-treated A.C., black carbon, polyvinyl acetate (PVAc), and methanol were mixed to make a gel compound, which was coated onto aluminum plates to fabricate electrodes. The optimal mixing ratio of A.C., black carbon, PVAc, and methanol was found to be 10 g: 2 g: 3 g: 20 mL. After fabrication, the electrodes were used in the batch-type experiment for $NH_3$ and $H_2S$ removal. The reduction rates of the gases were high at the beginning and slowly reduced with time. Dust collection experiments were conducted in continuous flow, with various voltages applied. Compared to 5 kV, dust removal efficiency was 1.5 times higher when 10 kV was applied. Increasing the number of electrodes applied also increased the collecting efficiency. The correlation coefficient between actual collecting efficiency and trend line was higher than 99%. Consequently, the novel dust collection system equipped with A.C. coated electrode appears to be a promising substitute for existing dust-control devices.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.863-867
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• 2008

Pitch based activated carbon fiber(ACF) was prepared from reformed naphtha cracking bottom oil(NCB oil) by melt spinning. The fibers obtained were stabilized, carbonized, and then steam activated. The ACF was sensitized with Pd-Sn catalytic nuclei via a single-step activation approach. This sensitized ACF was used as precursors for obtaining copper plated ACFs via electroless plating. ACFs uniformly decorated with metal particles were obtained with reduced copper plating in the reaction solution. Effects of the amount of copper on characteristics of ACF/Cu catalysts were investigated through BET surface area, X-ray diffraction, scanning emission microscopy, and ICP. The amount of copper increased with plating time, but the surface area as well as the pore volume decreased. NO conversion increased with reaction temperature. NO conversion decreased with increasing the amount of copper, which is seemed to be due to the reduction of surface area as well as the dispersion of copper.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.92-97
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• 2008

Selective catalytic reduction (SCR) of NO with ammonia was carried out over the physical mixture of $MnO_2$ and K or Cu-loaded activated carbons (AC) at low temperature. Introduction of oxygen affected positively the reduction of NO. Metal-impregnated AC showed significantly enhanced catalytic activity. Without water, the mixed catalyst of $MnO_2$ and K-loaded AC exhibited the best activity in the reduction of NO at $120^{\circ}C$. On the contrary, the activities of all the catalysts were significantly diminished in the presence of water. The mixed catalyst of $MnO_2$ and Cu-loaded AC treated with nitric acid and heat (1 : 1, w/w) exhibited the better activity for the reduction of NO than each single catalyst in presence of water.

• Environmental Engineering Research
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• v.13 no.2
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• pp.85-92
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• 2008

In this present study, we have synthesized Fe-containing AC(activated carbon)/$TiO_2$ composites with titanium (VI) n-butoxide (TNB) as a titanium source to Fe treated AC through an impregnation method. The result of the textural surface properties demonstrates that there is a slight decrease in the BET surface area of composite samples with an increase of the amount of Fe treated. The surface properties of scanning electron microscope (SEM) presented a characterization of a porous texture on the Fe-containing AC/$TiO_2$ composites and homogenous compositions for Fe and titanium dioxide distributed on the sample surfaces. Fe compound peaks and a titanium dioxide structure were observed in the X-ray diffraction patterns for the Fe-containing AC/$TiO_2$ composites. The results of chemical elemental composition for the Fe-containing AC/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for C, O, treated Fe components and Ti metal than that of any other elements. From the photo degradation results for the piggery waste, the Fe-containing AC/$TiO_2$ composites showed an excellent degradation activity for the chemical oxygen demand (COD) due to a photocatalysis of the supported $TiO_2$, radical reaction by Fe species and the adsorptivity and absorptivity of porous carbon.