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Pohang, South Korea

Jo E.-Y.,Korea Testing Laboratory | Park S.-M.,Korea Testing Laboratory | Yeo I.-S.,Korea Testing Laboratory | Cha J.-D.,Korea Testing Laboratory | And 3 more authors.
Desalination and Water Treatment

Wet scrubber is widely used to remove pollutants from a furnace flue gas or from other gas streams. However, high cost for the treatment or exchange of contaminated washed water is one of the problems. Electrocoagulation (EC) is an electrochemical method for treating polluted water, whereby sacrificial anodes dissolve to produce active coagulant precursors in the solution. This technology can be used for the removal of color, anionic contaminants, and colloidal particles. The goal of the present study was evaluation of EC process for treatment of wet scrubber wastewater and optimization of the process. In this study, the influence of electrode material and electrode distance on removal efficiency (%) of nitrate, sulfate, and total suspended solids (TSS) was investigated with synthetic wastewater. Using an Al electrode, 60.6% of nitrate, 50.0% of sulfate, and 96.8% of TSS were removed by EC treatment within 30 min. In case of Fe electrode, 69.7% of nitrate, 75.0% of sulfate, and 98.8% of TSS were removed. The treatment efficiency for real wet scrubber wastewater was evaluated with Fe electrode. After 180 min of EC treatment, 50% of color, 40% of nitrate, 40% of sulfate, and 95% of TSS were removed, respectively. All these results give clear evidence that EC process can effectively reduce the TSS, nitrate, and sulfate ions from wet scrubber wastewater. © 2015 Balaban Desalination Publications. All rights reserved. Source

Cho Y.,Korea Railroad Research Institute | Kwon S.-B.,Korea Railroad Research Institute | Park D.-S.,Korea Railroad Research Institute | Jung W.-S.,Korea Railroad Research Institute | Lee J.-Y.,Anytech Inc.
IAQVEC 2010: 7th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings

High carbon dioxide (CO 2) concentration of subway is one of the big environmental concerns in many countries. In Korea, new indoor air quality guideline for and subway was set to keep CO 2 concentration lower than 3,500 ppm at rush hours. In this study, CO 2 levels in Seoul metropolitan subway cars were monitored to check if CO 2 concentration in subway is really serious. And, it was found that CO 2 levels were often higher than 3,500 ppm during running. Usually, the ventilation is most widely used to control CO 2 concentration for normal indoor space. However, as for subway, because the outdoor air is usually polluted with high concentration of particulate matters, the ventilation is not appropriate sometimes. In addition, the ventilation in summer or winter season requires large amount of additional cooling or heating energy. Therefore, the introduction of an alternative way to substitute ventilation is urgently needed. In this study, an adsorptive CO 2 removal system was suggested. Zeolite was used as the adsorbent with our system. A prototype CO 2 removal system was tested in a subway car in which CO 2 is continually supplied artificially. The indoor CO 2 concentration could be kept lower than 1,500 ppm when the initial CO 2 was around 5,000 ppm. Further study on the regeneration method of used CO 2 adsorbent is undergoing. Source

Cho Y.,Korea Railroad Research Institute | Yang Y.-M.,Korea Railroad Research Institute | Park D.-S.,Korea Railroad Research Institute | Kwon S.-B.,Korea Railroad Research Institute | And 2 more authors.
Applied Mechanics and Materials

LiOH is known to be one of the most efficient CO2 adsorbent because it reacts with CO2 to form Li2CO3. However, LiOH still suffers from lack of enough hardness for practical use. In this study, various substrates were modified with LiOH. Their X-ray diffraction patterns were investigated, and LiOH peak was observed from all prepared samples. CO2 adsorption capacity of each prepared sample was measured by monitoring CO2 concentration change during the adsorption process under constant CO2 gas inflow condition. LiOH-modified Al2O3 and zeolite 5A showed good CO2 adsorption performance, while LiOH-modified AC and SiO2 showed relatively poor CO2 adsorption. Al2O3 and zeolite 5A contains many basic functional groups of Al3+, which promote the acid-base neutralization reaction with acidic CO2. The effect of carrier gas kind, carrier gas flow rate, initial CO2 concentration, and amount of loaded adsorbent was investigated. CO2 adsorption performance was better when the carrier gas was N2, because O2 competes with CO2 on LiOH. CO2 adsorption performance was better with lower carrier gas flow rate, lower initial CO2 concentration, and less loading of adsorbent due to the increase of contact time and contact points. © (2013) Trans Tech Publications, Switzerland. Source

Cho Y.,Korea Railroad Research Institute | Lee J.-Y.,Korea Railroad Research Institute | Bokare A.D.,Pohang University of Science and Technology | Kwon S.-B.,Korea Railroad Research Institute | And 6 more authors.
Journal of Industrial and Engineering Chemistry

In the present work, commercial zeolites 13X and 5A are embedded with LiOH (LEZ-13X and LEZ-5A) to remove CO2 under simulated indoor conditions. Although the BET surface area of both LEZ sorbents was much smaller than that of bare zeolite material, it showed highly enhanced CO2 adsorption capacity. The requirement of optimum moisture content for maximum CO2 adsorption was established by correlating the relative humidity (RH) values and CO2 uptake. The modified sorbents performed effectively even in presence of air or oxygen carrier gas, which demonstrated its viability to adsorb CO2 from indoor environments at ambient conditions. © 2014 The Korean Society of Industrial and Engineering Chemistry. Source

Lee J.Y.,Anytech Inc. | Lee J.Y.,Kyung Hee University | Lim Y.H.,Anytech Inc. | Lim Y.H.,Kyung Hee University | And 3 more authors.
Bulletin of the Korean Chemical Society

A catalyst of Ag with alumina has been widely used for the decomposition of odorous ammonia. In order to meet cost effectiveness, copper was added with five different doping ratios of Ag/Cu in this work, and NH3 decomposition was examined at 150-400 -°C. Experimental results show that the catalyst doped with only Cu shows very weak potential to oxidize NH3 despite its excellent selectivity for nitrogen molecules than NO or N2Oat temperatures over 300 -°C. Analysis by X-ray photoelectron spectroscopy indicates thatAg0 is the major chemical functionality that determines the decomposition rate of NH3 at low temperature, e.g., 200 -°C, while Ag+ and Ag2+ are efficient at higher temperatures. Among the five segregated copper functionalities, only Cu 2pa/2 appeared to be favorable for the activity of Ag particles. It was found from the experimental results that Ag/Cu = 1:9 could provide a cost-effective combination for the low temperature regime. © 2015 Korean Chemical Society , Seoul & Wiley-VCH Verlag GmbH & Co. KGaA , Weinheim. Source

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