• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.532-539
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• 2011

The physical and chemical properties of the dried low rank coals (LRCs) before and after the surface treatment using ozone and ammonia were characterized in this study. The contents of moisture, volatiles, fixed carbon and ash consisting of dried LRCs before the surface treatment were about 2.0, 44.8, 44.9 and 8.9%, respectively. Also, it was composed of carbon of 62.66%, hydrogen of 4.33%, nitrogen of 0.94%, oxygen of 27.01% and sulfur of 0.09%. The dried LRCs was surface-treated with the various dry methods using gases such as ozone at room temperature, ammonia at $200^{\circ}C$ and then the dried LRCs before and after the surface treatment were characterized by the various analysis methods such as FT-IR, TGA, proximate and elemental analysis, caloric value, ignition test, adsorption of $H_2O$ and $NH_3-TPD$. As a result, the oxygen content increased and the calorific value, ignition temperature and the contents of carbon and hydrogen relatively decreased because the oxygen-contained functional groups were additionally generated by the surface oxidation with ozone which plays a role as an oxidant. Also, its $H_2O$ adsorption ability got higher because the hydrophilic oxygen-contained functional groups were additionally generated by the surface oxidation with ozone. On the other hand, it was confirmed that the dried LRCs after the surface treatment with $NH_3$ at $200^{\circ}C$ have the decreased oxygen content, but the increased calorific value, ignition temperature and contents of carbon and hydrogen because of the decomposition of oxygen-contained functional groups the on the surface. In addition, the $H_2O$ adsorption ability was lowered bucause the surface of the dried LRCs might be hydrophobicized by the loss of the hydrophilic oxygen-contained functional groups. It was concluded that the various physico-chemical properties of the dried LRCs can be changed by the surface treatment.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.445-457
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• 2000

This study was carried out comparing with ozone oxidation and photocatalytic degradation for removal of geosmin. In the change of pH, Ozonation, UV-Germicidal lamp and Halogen lamp irradiation and Halogen $lamp/TiO_2$ Powder was very slowly changing, but UV-Germicidal $lamp/TiO_2$ Powder was rapidly changed from 7.0 to 7.7 until 300min of irradiation time, and varied a little after. Geosmin degradation ratio was as following, UV-Germicidal $lamp/TiO_2$ $Powder(200mg/L){\geq}O_3$ > UV-Germicidal $lamp/TiO_2$ $Pw(100mg/L)$ > UV-Germicidal lamp > Halogen lamp. The result of investigation of generated by-products were 3-Heptanone, two sort of aldehydes and three sort of alcohols by ozonation. But It was not generated by photocatalytic degradation.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.28.1-28.1
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• 2011

Radiation-induced displacement damage which has caused the increase of the dark current in the focal plane adopted in the Ozone Monitoring Instrument (OMI) was studied in regards of the primary protons and the secondaries generated by the protons in the orbit. By using the Monte Carlo N-Particle Transport Code System (MCNPX) version 2.4.0 along with the Stopping and Range of Ions in Matter version 2010 (SRIM2010), effects of the primary protons as well as secondary particles including neutron, electron, and photon were investigated. After their doses and fluxes that reached onto the charge-coupled device (CCD) were examined, displacement damage induced by major sources was presented.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.64-71
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• 2007

The main purpose of this study is to analyze the characteristics of toluene removal by plasma, photocatalyst, and plasma/photocatalyst system with the major parameters such as flow rate, inlet toluene concentration and applied voltage, etc., experimentally. In the combined plasma/photocatalyst process, rates of toluene conversion are represented as 99% at flow rate 250, 500 mL/min while, below 97% at flow rate 1000 mL/min due to the low residence time(reaction time) at the same applied voltage 4173 voltage and toluene inlet concentration 50 ppm. The intermediate products are detected by GC/MS analysis showing the small amounts of benzoic acid, benzyl alcohol and residual ozone concentration $0.04{\sim}0.05$ ppm generated by plasma process in the present system.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1261-1266
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• 2004

Dielectric Barrier Discharge (DBD) in air, which has been established for the production of large quantities of ozone, is more recently being applied to a wider range of aftertreatment processes for HAPs (Hazardous Air Pollutants). Although DBD has high electron density and energy, its potential use as precharging nano and submicron particles are not well known. In this work, we measured I-V characteristics of DBD and estimated collection efficiency of the particles by DBD type 2-stage ESP. To examine the particle collection with various applied voltage waveforms of DBD for nano and submicron sized, bimodal particles were generated by a electrical tube furnace and an atomizer.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.40-46
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• 2007

A laboratory scale experiment on phenol conversion properties by pulsed corona discharge process was carried out. Effects of operating parameters such as applied voltage, input oxygen, and electrode geometry on phenol conversion and solution properties were investigated. Electrical discharges generated in liquid phase increased the liquid temperature by heat transfer from current flow, decreased the pH value by producing various organic acids from phenol degradation, and increased conductivity by generating charge carriers and organic acids. The oxygen supply enhanced the phenol conversion through the ozone generation dissolution and the production of OH radicals. Series type electrode configuration induced more ozone production than reference type configuration because it produced gas phase discharges as well as liquid phase discharges. Therefore, the higher phenol conversion and TOC(total organic carbon) removal efficiency were obtained in series type configuration.

• Fire Science and Engineering
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• v.28 no.6
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• pp.108-113
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• 2014

The combined process of Sliding Arc Plasma and corona dielectric barrier discharge process (CDBD) was used to efficiently improve harmful substance, which convert into OH radicals which have strong oxidation potential, and so have deodorization and sterilizing effects, by generating specific radicals and anion and then reacting with the moisture contained in harmful substance. As a result of experiment, even if the size of SAP reactor is reduced from 80 A to 50 A, there is no much change and therefore it is judged the size of reactor may be minimized. And it was confirmed that after the anion and ozone generated from CDBD rector react with harmful substance, a anion was reduced from 510,000 ppb to 470 ppb and ozone from 98 ppb to 22 ppb. It was also judged the stability and durability of plasma producer are excellent. Accordingly, it is considered the harmful substances which exist in indoor air quality will be efficiently improved and removed by using further plasma combined process through this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.544-549
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• 2017

This paper aims to examine the effect of rotational fluid motion about the efficiency of the gas - liquid ejector, which is a core unit in a ship equilibrium water treatment system. The ejector is a device for injecting ozone into ship equilibrium by the negative pressure generated by exchange of momentum between water and ozone. The existing ejector ejects the driving fluid with a simple form. In this paper, however, a rotation induction device is applied to the driving nozzle so that the driving fluid can be rotated and injected. To investigate the flow characteristics by the rotational movement of the driving fluid, CFD was used. The pressure and flow rate of the driving fluid, the negative pressure and suction flow rate of the suction fluid in the suction part, and the discharge pressure were predicted. On the basis of the results, the efficiency of the ejector using the rotation induction system was 22.25%, which was about 1.7% better than that of the existing ejector. Finally, to verify the feasibility of the CFD, an experiment was conducted on the ejector using the rotation induction device and the results were similar to those of the CFD.

• Resources Recycling
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• v.22 no.6
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• pp.55-63
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• 2013

In this study, a electrochemical-chemical combined dissolution technology was conducted by electro-generated chlorine to obtain ruthenium solution from ruthenium metal. To find out the optimum leaching conditions of ruthenium in chloride solution, this leaching process was carried out on the variation of pH, reaction time, temperature and applied voltage at the electro-generated chlorine system in the reaction bath. Also, ozone generator was used to obtain ruthenium(III) chloride solution to increase the leaching rate. The optimum condition was observed at pH 10.0, $40^{\circ}C$ within 1 hr of reaction time that more than 88% of ruthenium(III) chloride dissolved.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.183-189
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• 2007

We have investigated the oxidation of gas phase elemental mercury using dielectric barrier discharge (DBD). In the DBD process, active species such as $O_3$, OH, O and $HO_2$ are generated by collisions between electrons and gas molecules. Search active species convert elemental mercury into mercury oxide which is deposited into the wall of DBD reactor because of its low vapor pressure. The oxidation efficiency of elemental mercury has been decreased from 60 to 30% by increasing the initial concentration of the elemental mercury from 72 to $655{\mu}g/Nm^3$. The gas retention time at the DBD reactor has showed the little effect on the oxidation efficiency. The more oxygen concentration has induced the more oxidation of elemental mercury, whereas there has been no appreciable oxidation within pure $N_2$ discharge. It has indicated that oxygen atom and ozone, generated in air condition determine the oxidation of elemental mercury.