• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.491-498
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• 2009

We studied to develop high-efficiency removal system of odor and VOCs(Volatile Organic Compounds) from environmental infrastructure facilities and oil refineries, painting facilities and so on. It can replace RTO and RCO. We tried an removal experiment for VOCs (toluene, xylene, benzene, MEK(methyl ethyl ketone), ethanol, formalin etc. and odor compounds (hydrogen sulfide, etc.). In process, as pre-treatment we used the scrubber with vortex flow (Multi-scrone) to remove the hydrophilic VOCs and as post-treatment, used fibrous bio-filter to remove the hydrophobic VOCs. This hybrid system remove with high efficiency both the hydrophilic VOCs and hydrophobic VOCs. And we tried to make this system to be compact. In experiment using Multi-scrone, contact time is 2~3 seconds and absorption scrubbing water is diaphragm-type electrolysis water. hydrophilic VOCs like ethanol and relatively hydrophilic odor compounds like hydrogen sulfide is excellent, these substances has been removed almost completely, respectively 95~99%, 93~97%. And for MEK, formalin also Showed a high removal efficiency, respectively 78~90%, 72~85%. But in experiment using Multi-scrone, the hydrophobic VOCs like BTX showed a low removal efficiency, respectively 16~22%, 12~18%, 8~16%. In hydrophobic VOCs, toluene removal experiment using fibrous bio-filter, early efficiency was low but after 10days, adaptation period showed high efficiency 85~95%. but in the mixed phase, toluene and MEK efficiency reduced 5~10%. this show microorganism treat first MEK easy to remove. The removal efficiency for MEK using the fibrous biofilter was stable, 80~92%. This hybrid system is also high economical efficiency for RTO. This system reduce more than 50% the cost of equipment and maintenance. As a result, we expect this technology is in the limelight as high efficiency treatment of VOCs in mid-low price.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.104-114
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• 2015

Objectives: The purpose of this study is to investigate the atmospheric concentration of VOCs and the urinary concentration of t,t-MA, HA, MA in the industrial complex of Yeosu, South Jeolla Province. Methods: In order to study seasonal patterns of air concentration of VOCs, measurements were taken at five sampling sites around Yeosu from June 2013 to June 2014. Urinary metabolite excretionsfrom 671 subjects, exposure and comparison area were analyzed. Results: The average concentration of VOCs in the air was 1.53ppb for benzene, 0.73ppb for toluene, 0.22ppb for ethylbenzene, 0.52ppb for xylene and 0.12ppb for styrene. The concentration of benzene was somewhat higher than the year-average standard ($5{\mu}g/m^3$, about 1.5ppb) of the domestic air-environment criteria newly established in 2010.The metabolic concentration of VOCs in the urine of the entire sample was analyzed at $47.76{\mu}g/g\;cr.$, 213.07mg/g cr., and $290.09{\mu}g/g\;cr.$ for t,t-MA, HA, and MA, respectively. Compared with the average values for Korea as presented in the first basic survey of national environmental conservation ( $49.8{\mu}g/g\;cr.$ for t,t-MA, 0.17g/g cr. for HA, and 0.26mg/g cr. for MA), the metabolic concentrations of HA and MA in urine were higher than the average values. Conclusions: The concentration of VOCs in the air and urinary metabolites of the exposed and control areas showed that the concentrations of all substances were higher in the exposed area than in the control area.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.1
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• pp.31-41
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• 2019

Volatile organic compounds(VOCs) are toxic carcinogenic compounds found in wastewater. VOCs require rapid removal because they are easily volatilized during wastewater treatment. Electrochemical advanced oxidation processes(EAOPs) are considered efficient for VOC removal, based on their fast and versatile anodic electrochemical oxidation of pollutants. Many studies have reported the efficiency of removal of various types of pollutants using different anodes, but few studies have examined volatilization of VOCs during EAOPs. This study examined the removal efficiency for VOCs (chloroform, benzene, trichloroethylene and toluene) by oxidization and volatilization under a static stirred, aerated condition and an EAOP to compare the volatility of each compound. The removal efficiency of the optimum anode was determined by comparing the smallest volatilization ratio and the largest oxidization ratio for four different dimensionally stable anodes(DSA): Pt/Ti, $IrO_2/Ti$, $IrO_2/Ti$, and $IrO_2-Ru-Pd/Ti$. EAOP was operated under same current density ($25mA/cm^2$) and electrolyte concentration (0.05 M, as NaCl). The high volatility of the VOCs resulted in removal of more than 90% within 30 min under aerated conditions. For EAOP, the $IrO_2-Ru/Ti$ anode exhibited the highest VOC removal efficiency, at over 98% in 1 h, and the lowest VOC volatilization (less than 5%). Chloroform was the most recalcitrant VOC due to its high volatility and chemical stability, but it was oxidized 99.2% by $IrO_2-Ru/Ti$, 90.2% by $IrO_2-Ru-Pd/Ti$, 78% by $IrO_2/Ti$, and 75.4% by Pt/Ti anodes The oxidation and volatilization ratios of the VOCs indicate that the $IrO_2-Ru/Ti$ anode has superior electrochemical properties for VOC treatment due to its rapid oxidation process and its prevention of bubbling and volatilization of VOCs.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.635-642
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• 2006

Present study evaluated the low-temperature destruction of n-hexane and benzene using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst. The parameters tested for the evaluation of catalytic destruction efficiencies of the two volatile organic compounds(VOC) included input concentration, reaction time, reaction temperature, and surface area of catalyst. It was found that the input concentration affected the destruction efficiencies of n-hexane and benzene, but that this input-concentration effect depended upon VOC type. The destruction efficiencies increased as the reaction time increased, but they were similar between two reaction times for benzene(50 and 60 sec), thereby suggesting that high temperatures are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Similar to the effects of the input concentration on destruction efficiency of VOCs, the reaction temperature influenced the destruction efficiencies of n-hexane and benzene, but this temperature effect depended upon VOC type. As expected, the destruction efficiencies of n-hexane increased as the surface area of catalyst, but for benzene, the increase rate was not significant, thereby suggesting that similar to the effects of the re- action temperature on destruction efficiency of VOCs, high catalyst surface areas are not always proper for economical thermal destruction of VOCs. Depending upon the inlet concentrations and reaction temperatures, almost 100% of both n-hexane and benzene could be destructed, The current results also suggested that when applying the mesh type transition Metal Pt/SS catalyst for the better catalytic pyrolysis of VOC, VOC type should be considered, along with reaction temperature, surface area of catalyst, reaction time and input concentration.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.503-511
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• 2009

VOC mixture was fed to a trickle bed air biofilter (TBAB) with step-change in influent mixture concentrations from 50 ppmv to 1,000 ppmv, corresponding to loadings of $5.7\;g/m^3/hr$ to $114.1\;g/m^3/hr$. VOC mixture was an equimolar ratio of two aromatic VOCs, i.e., toluene and styrene, and two oxygenated VOCs, i.e., methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK). The TBAB system employed backwashing as biomass control. The experimental results showed that a critical loading rate for VOC mixture removal was determined to be about $60\;g/m^3/hr$, and critical loading rates for individual VOCs in the mixture were different. Specifically, toluene content in the mixture played a major role in the biofilter overall performance. As VOC mixture was fed beyond the critical loading rate, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing was delayed, which was a critical factor in the biofilter performance. In the mass balance analysis, 63.8% of the carbon equivalent in VOCs removal was used for $CO_2$ production during the experimental runs. The 82.6% nitrogen utilized in the biofilter was contributed to microbial cell synthesis. The obtained results were compared against consistently high efficient performance of TBAB for VOC mixture by employing backwashing as biomass control.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.5
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• pp.369-381
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• 2009

The objective of this study was to simulate surface air pollutants and to examine reliability of mobile emission for CMAQ system using an observation-based approach in the Seoul Metropolitan Area. Accurate assessment of emissions from mobile source is one of the most debatable parts in the entire emissions inventory process. For this study, we evaluated the official emission inventories of Volatile Organic Compounds (VOCs) and nitrogen oxides ($NO_x$) using an observation-based approach. In this paper, we achieved VOCs/CO and $NO_x$/CO ratios derived from ambient measurements taken from June to August of 2005 in early morning (07:00~08:00). And we compared them with those derived from the emission inventory. Based on these ratios and on the assumption that official inventory of CO emissions is reasonably accurate, mobile emissions of $NO_x$ seem to be slightly overestimated and VOCs emissions significantly underestimated. The results of simulations using modified emission of mobile source were in closer agreement with the observation results except NO. Predicted NO values based on revised $NO_x$ emissions were considerably lower than the observed values. Using modified emission inventories brings the modeled values into closer agreement with observed ozone levels in Seoul. Especially in case of CO, $NO_x$ and VOCs emission, the modified values were suitable for simulating ozone levels in Seoul and Gyeonggi. However, ozone values predicted using the modified emissions were higher than the observed and predicted values based on original emissions. According to the 95 percentile ozone concentrations, emission revised by CO, $NO_x$ and VOCs from mobile source was the best for predicting high concentration.

• Analytical Science and Technology
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• v.19 no.5
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• pp.422-432
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• 2006

The volatile organic compounds(VOCs) have been recognized as a major contributor to air pollution. The catalytic oxidation is one of the most important processes for VOCs destruction due to getting high efficiency at low temperature. In this study, monometallic Pt and bimetallic Pt-Ru, Pt-Ir were supported to ${\gamma}-Al_2O_3$. Xylene, toluene and MEK were used as reactants. The monometallic or bimetallic catalysts were prepared by the excess wetness impregnation method and were characterized by XRD, XPS, TEM and BET analysis. As a result, Pt-Ru, Pt-Ir bimetallic catalysts showed higher conversion than Pt monometallic catalyst. Pt-Ir bimetallic catalyst showed the highest conversion on the ${\gamma}-Al_2O_3$ support. In the VOCs oxidation, Pt-Ru, Pt-Ir bimetallic catalyst had multipoint active sites, so it improved the range of Pt metal state. Therefore, bimetallic catalysts showed higher conversion of VOCs than monometallic ones. In this study, the use of small amount of Ru, Ir to Pt promoted oxidation conversion of VOCs.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.193-203
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• 2020

Volatile compounds (VOCs) are not only media for communication within a species but also effective tools for sender to manipulate behavior and physiology of receiver species. Although the influence of VOCs on the interactions among organisms is evident, types of VOCs and specific mechanisms through which VOCs work during such interactions are only beginning to become clear. Here, we review the fungal volatile compounds (FVOCs) and their impacts on different recipient organisms from perspective of distinct lifestyles of the filamentous fungi. Particularly, we discuss the possibility that different lifestyles are intimately associated with an ability to produce a repertoire of FVOCs in fungi. The FVOCs discussed here have been identified and analyzed as relevant signals under a range of experimental settings. However, mechanistic insight into how specific interactions are mediated by such FVOCs at the molecular levels, amidst complex community of microbes and plants, requires further testing. Experimental designs and advanced technologies that attempt to address this question will facilitate our understanding and applications of FVOCs to agriculture and ecosystem management.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E4
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• pp.157-168
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• 2003

This study evaluated the technical feasibility of the application of titanium oxide (TiO$_2$) photocatalysis for the removal of VOCs in low ppb concentrations commonly associated with non -occupational indoor air quality issues. A series of experiments were conducted to evaluate four parameters (relative humidity (RH), hydraulic diameter (HD), photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) for the PCO destruction efficiencies of the selected target VOCs. None of the target VOCs presented significant dependency on the RH, which is inconsistent with a few previous studies. However, it is noted that the three parameters (HD, RM and IPS) should be considered for better VOCs removal efficiencies for the application of TiO$_2$ photocatalytic technology for cleansing non -occupational indoor air. The PCO destruction of VOCs at concentrations associated with non-occupational indoor air quality issues can be up to nearly 100％. The amount of CO generated during PCO would be negligible in comparison to the indoor CO levels. These results can make the PCO reactor an important tool in the effort to improve non-occupational indoor air quality.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.1
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• pp.17-22
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• 2023

Purpose: VOCs (volatile organic compounds) are all the organic compounds that react with solar rays and increase the concentration of ozone in the troposphere and are partially also known as carcinogens. The adsorption using activated carbon is usually applied to remove VOCs. Research design, data and methodology: The 20 places of surface coating facilities were selected to evaluate the emission amount of VOCs in Seoul. In addition, the removal efficiency of VOCs in 25 places of automobile coating facilities was evaluated. Results: The average emission amount of VOCs was 10.903 kg/hr from automobile coating facilities, while 3.520 kg/hr from other surface coating facilities. The removal efficiency in adsorption with the combustion catalytic process has the mean value of 87.9% and the regeneration efficiency of activated carbon has the mean value of 95.0%. Conclusions: The removal efficiency in adsorption with the biofiltration process has the mean value of 89.8% and the regeneration efficiency of activated carbon has the mean value of 94.8%. The removal efficiency in the plasma catalyst process has the mean value of 79.3%.