• Resources Recycling
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• v.29 no.6
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• pp.41-47
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• 2020

This study was carried out to utilize the coal bottom ash generated in a circulating fluidized bed combustion boiler as a treatment agent for heavy metal ions, and experiments were conducted to remove heavy metal ions from the acid mine drainage. The batch experiments were conducted to investigate the influence of dosage of ash, initial concentration of solution on the removal capacity of heavy metal ions (Cu, Cd, Cr, Pb). The results of the experiment showed that the total removal capacity of heavy metals was 30.8 mg/L and 46.4 mg/g, respectively, under the condition that the concentration of coal ash was added as 15 g/L of heavy materials and 10 g/L of light materials. After that, a long-term column experiment was performed to determine the maximum removal capacity of heavy metal ions (Cu, Cd, Cr, Pb, As), and the removal capacity for each metal component was investigated. After approximately 60 days of operation, the maximum removal capacity of heavy metals was 23.6 mg/g at pH 9.25.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.648-652
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• 2004

A comparative investigation of an experimental and a simulation of chemical kinetics for NOx removal from dielectric barrier discharges is presented. Several types of dielectric barrier discharges were implemented depending upon the configuration of electrodes. The simulation was based on an approximate mathematical model for plasma cleaning of waste gas. The influence of non uniform distributions of species due to the production of primary active particles in the streamer channel was taken into account. A comparison of observed experimental to the calculated removal efficiency of NOx showed acceptable agreement.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.40-44
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• 2004

To the removal of hardness materials, we've test the absorptive capacity of main material $Mg^{2+},\;Ca^{2+}$ on the using the activated carbon powder saturated in 0.1M Nitrilotriacetic acid by experimental methods. The absorptive properties of $Ca^{2+}\;and\;Mg^{2+}$ were measured with absorbent quantity and contact time., and investigated the physical properties of overall rate constant and adsorption constant adsorption isotherm, and Langmuir and Freundlich constant. In case of k' adsorption rate constants of $Ca^{2+},\;Mg^{2+}$, was 0.00299, 0.00529 by Bhattahary and Venkobachar equation. $k_{aa}$ was 0.00373, 0.00640 according with adsorption rate constants of Lagergren.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.385-388
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• 2005

In this study, the objective is to develope environment friendship mineral pigments for removal of harmful chemical substance. Environment friendship mineral pigments made of Slag blast furnace-photocatalyst carriers were developed to identify their removal effects of NOx, HCHO and VOCs(benzene, Toluene) on sunlight, fluorescent light and UV lamp. In case of NOx at UV light, the eliminative ability was been better than different harmful materials, and it was appeared large degree rather than different harmful materials.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.249-252
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• 2000

To overcome problems of excavation technology far repairing or replacing underground buried pipes which are worn out or damaged, various trenchless repair-reinforcement technologies have been invented. But these trenchless technologies also have many problems in the aspect of economy and convenience of operation. In this research, the repair-reinforcement process using RTM (Resin Transfer Molding) which can solve problems of present trenchless technologies was developed. The resin wetting and void removal during RTM process to form large composite structures inside of buried pipes were experimentally investigated. From the experiment, it was found that the new technology had advantage over conventional methods by employing appropriate process parameters and void removal vents.

• Carbon letters
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• v.5 no.3
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• pp.103-107
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• 2004

The atmospheric pressure plasma treatments ($Ar/O_2$ and $Ar/N_2$) of activated carbon fibers (ACFs) were carried out to introduce hydrophilic functional groups on carbon surfaces in order to enhance the hydrogen chloride gas (HCl) adsorption. Surface properties of the ACFs were determined by XPS and SEM. $N_2$/77 K adsorption isotherms were investigated by BET and D-R (Dubinin-Radushkevich) plot methods. The HCl removal efficiency was confirmed by HCl detecting tubes (range:1~40 or 40~1000 ppm). As experimental results, it was found that all plasma-treated ACFs showed the decrease in the pore volume, but the HCl removal efficiency showed higher level than that of the untreated ACFs. This result indicated that the plasma treatments led to the conformation of hydrophilic functional groups on the carbon surfaces, resulting in the increase of the interaction between the ACFs and HCl gas.

• Archives of Metallurgy and Materials
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• v.66 no.3
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• pp.771-776
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• 2021

Iron oxide nanoparticles were incorporated to form composite microspheres of SiO₂ and Fe₂O₃ for magnetic separation of the particles after adsorption or photochemical decomposition. Economic material, sodium silicate, was purified by ion exchange to prepare aqueous silicic acid solution, followed by mixing with iron oxide nanoparticles. Resulting aqueous dispersion was emulsified, and composite microspheres of SiO₂ and Fe₂O₃ was formed from the emulsion droplets as micro-reactors during heating. Removal of methylene blue using the composite microspheres was performed by batch adsorption process. Synthesis of composite microspheres of silica containing Fe₂O₃ and TiO₂ nanoparticles was also possible, the particles could be separated using magnets efficiently after removal of organic dye.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.9-16
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• 2009

Further treatment facility using various filter materials was evaluated to treat effluent of constructed wetland. Further treatment facility was installed with 1m length in outlet of 3 constructed wetland (unplanted constructed; reed bed constructed wetland; cattail bed constructed wetland) using 3 filter materials (slag, activated carbon, oyster shell). Flow rate of three further treatment facility was 63 $m^3$/day (slag), 19 $m^3$/day (activated carbon), and 81 $m^3$/day (Oyster shell). COD removal rate of slag, activated carbon, and oyster shell was 6 %, 24 %, 1 %, and removal mass was 32 g/day, 30 g/day, and 5 g/day, respectively. All of further treatment facility was effective to removal organic materials. T-N and T-P removal rate of activated carbon was 24 % and 4 %, and slag and oyster shell was not effective to remove T-N and T-P. Overall, further treatment facility was effective to remove organic mater, constructed wetland combined with further treatment facility can remove nutrient and organic matters effectively.

• Korean Journal of Materials Research
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• v.16 no.8
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• pp.497-502
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• 2006

Recently, many attention have been focused on illite as a material for the well-being industry. Illite contains various kinds of iron bearing materials and they restrict their usage. In this study, Fe impurities in the illite produced in Yeongdong-gun, Chungcheongbuk-do were characterized and their removal experiments were performed. According to the characterization of illite raw ore, it contained 1.54 wt.%$Fe_2O_3$ due to the existence of iron oxide($Fe_2O_3$) and pyrite($FeS_2$). The raw ore was crushed into 3 mm or less using cone crusher and then ground by rod mill for the liberation of impurity mineral. For the removal of iron bearing minerals, an acid treatment, a flotation, a magnetic separation, and a flotation combined with magnetic separator were performed respectively. When the illite raw ore was treated with magnetic separation and various kinds of acid, 1.54wt.%. $Fe_2O_3$ content was reduced to 0.78 and 1.0 wt.%, respectively. On the other hand $Fe_2O_3$ content was reduced to be 0.52 wt.% after flotation. These results indicate that iron bearing minerals cannot be reduced below 0.3wt.%$Fe_2O_3$. However, combination of magnetic separation and flotation enable us to get 0.24wt.% of illite concentrate. It is concluded that, for the refinement of illite from Yeongdong-gun, the flotation combined with magnetic separation is good for high purity illite.

• Particle and aerosol research
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• v.16 no.1
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• pp.1-8
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• 2020

Nano-pulse plasma technology has great potential as the process simplicity, high efficiency and low energy consumption for SO₂ removal. The research on the gas-to-particle conversion is required to achieve higher efficiency of SO₂ gas removal. Thus, we studied the effect of the relative humidity, NH₃ concentration and applied voltage of the nano-pulse plasma system in the gas to particle conversion of SO₂. The particles from the conversions were increased from 10 to 100 nm in diameter as relative humidity, NH₃ concentration, applied voltage increases. With these results, nano-pulse plasma system can be used to more efficient removal of SO₂ gas by controlling above parameters.