• Membrane Journal
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• v.17 no.2
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• pp.99-111
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• 2007

It is impossible to remove toxic organic substances that are recognized as a cancer caused suspicious element in drinking water using the conventional water purification method. This study introduces groundwater into a reaction chamber as an effective amount of water to process this water using a mixed method of AOP oxidation and M/F membrane and purifies it as a desirable level by artificially mixing such toxic substances in order to effectively process the water. Based on this fact, this study configures an optimal operation condition. The VOCs existed in toxic substances was investigated as a term of phenol and toluene, and agricultural chemicals were also investigated as a term of parathion, diazinon and carbaryl. The experiment applied in this study was performed using a single and composite soolution. In the operation condition applied to fully dissolve and remove such substances, the amount of $H_2O_2$ injected in the process was 150 mL of a fixed quantity, the value of pH was configured as $5.5{\sim}6.0$, the temperature was controlled as a range of $12{\sim}16^{\circ}C$, the dissolved amount of ozone was applied more than 5.0 mg/L, the reaction time was determined as an optimal condition, such as $30{\sim}40$ minutes, and the segregation membrane in the same reactor was determined for acquire water drinking of large quantity using a pore size of $0.45{\mu}m$ M/F membrane.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.99-104
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• 2007

Porous silicon exhibiting dual optical properties, both $Febry-P{\acute{e}}rot$ fringe (optical reflectivity) and photoluminescence had been developed and used as chemical sensors. Porous silicon samples were prepared by an electrochemical etch of p-type silicon wafer (boron-doped, <100> orientation, resistivity ; $1-10{\Omega}cm$). Two different types of porous silicon, fresh porous silicon (Si-H terminated) and oxidized porous silicon (Si-OH terminated)by the thermal oxidation, were prepared. Then the samples were exposed to the vapor of various organics, such as methanol, acetone, hexane, and toluene. Both reflectivity and photoluminescence were simultaneously measured under the exposure of organic vapors for sensing VOC's. These surface-modified samples showed unique respond in both reflectivity and photoluminescence with various organic vapors. While polar molecules exhibit greater quenching photoluminescence, molecules having higher vapor pressure show greater red shift for reflectivity.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.639-646
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• 2007

This study performed several tests for the durability of the concrete coated with nano synthesis ceramics which do not contain volatile organic compounds harmful to environment. The tests were adhesion test on dry and humid concrete, SEM test, MIP analysis, carbonation, chloride diffusion by electronic facilitation, freezing-thawing resistance, alkaline resistance, and brine resistance test. In the adhesion test on dry and humid concrete, nano synthesis ceramics coating produced the highest results among all the coatings tested. Nano synthesis ceramics adhered solidly on the concrete surface. The adhesive strength seemed to result from the hydrogen bond between nano synthesis ceramics which are inorganic and generated by hydrolysis and re-condensation reaction and the concrete's hydrates such as calcium silicate aluminate or calcium silicate hydrate. SEM test and MIP analysis results show surface structure with finest crevices pore in the nano synthesis ceramics coating applied concretes. In the carbonation, chloride diffusion, and freezing-thawing resistance tests, the concretes with nano synthesis ceramics coating indicated the best results. Based on these test results, further progress in application of nano synthesis ceramics coatings to various concrete structures including costal structures and sewerage arrangements can be expected.

• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.239-248
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• 2006

Improvements in understanding the effects of dietary fermentable carbohydrates and their interaction with supplemental feed enzymes and the feed manufacturing process may lead to reductions in volatile organic compound (VOC) emissions from poultry manure. Starch digestibility has been improved by replacing ground wheat or barley with whole wheat or barley, but there was no consistent effect of cereal species or feed form on the pH value of the gizzard contents. Pelleting results in improvements in feed conversion from 0 to 12%. Starch digestibility has been reported to account for up to 35 % of the improvement in available metabolic energy as a result of xylase supplementation. Factors which affect starch utilization and non-starch polysaccharide (NSP) absorption include the presence of anti-nutrient facto. (ANF) in grains, the nature of grain starch, NSP and the digestive capacity of animals. Improvements in feed production technology have been made in enzyme stabilization, allowing some dry enzyme products to be pelleted after conditioning at up to $87.69^{\circ}C$ and liquid enzymes to be stored in the feed mill for up to low months prior to use. The soluble NSP, arabinokylans and beta-glucans are partially degraded into smaller fragments by enzymes. With fragmentation, the water holding capacity is decreased, which leads to a reduction in digesta moisture, wet feces, and dirty eggs from hens fed diets containing viscosity-inducing ingredients.

• Journal of the Korean Institute of Gas
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• v.14 no.3
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• pp.1-7
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• 2010

According to Indoor Air Quality(IAQ) management law for multi-use buildings, SEEONE CO., Ltd. made pilot and tested it to remove minute particle, odor, VOCs, etc. within the standards of IAQ. This pilot made by SEEONE CO., Ltd. is vortex scrubber washing electrolyzed water. As 30 minutes test result in multi-use building indoor place, minute particle(the smoke of a cigarette) was reduced $920{\mu}g/m^3{\rightarrow}112{\mu}g/m^3$, gaseous contaminants was reduced Formaldehyde (HCHO) 20ppm$\rightarrow$4ppm, Ammonia($NH_3$) 50ppm$\rightarrow$1ppm, Trimethylamine ($(CH_3CH_2)_3N$) 15ppm$\rightarrow$trace, Methylethylketone($CH_3COC_2H_5$) 25ppm$\rightarrow$trace, Acetic acid ($CH_3COOH$) 20ppm$\rightarrow$trace, Acetaldehyde($CH_3CHO$) 15ppm$\rightarrow$2ppm and Acetone($CH_3COCH_3$) 50ppm$\rightarrow$N.D. The pilot test result of the air filter using electroyzed water in vortex scrubber showed high removal efficiency. Because purified air maintain indoor humidity of approximately 40~60%, so users can feel pleasant. In E.coli, S.aureus sterilization test and CODcr, turbidity treatment test by electrolysis, germs was sterilized over 99.99% and CODcr and turbidity was decreased gradually. So water used for washing can be reused by electrolysis.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.1955-1968
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• 2000

Thermal gravimetric change characteristics and gas phase product - CO, NO, $NO_2$, VOCs - generated in the process of pyrolysis and oxidation. were investigated with variation of process parameters including furnace reactor temperature both in pyrolytic and oxidative conditions. For the thermal gravimetric change characteristics. paper and wood were mainly decomposed at lower temperatures and they had similar thermal gravimetric change trend due to their similar compositions; plastics were mainly decomposed at higher temperatures; in the case of textile. natural compounds were decomposed at lower temperatures and synthetic compounds at relatively higher temperatures; food was decomposed in the wide range of temperatures possibly due to their different kinds of components. For the analysis results of gas phase product. the concentrations of NO, $NO_2$ were detected at higher level at the oxidative conditions than at the pyrolytic conditions except that of CO, which is due to complete combustion with sufficient oxygen at the oxidative condition; food gave off CO, NO, $NO_2$ more than the other wastes. VOCs were emitted more at the pyrolytic conditions than at the oxidative conditions.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.523-538
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• 2009

Recently, there has been a keen demand for real-time automatic monitoring of VOCs not only in Korea but other developed countries. We carried out this study to evaluate and to optimize the performance of a continuous automatic monitoring system for hazardous VOCs (HVOCs) in the ambient atmosphere, using an on-line GC system. The online system normally consisted of a Nafion dryer prior to a cold trap of an automatic thermal desorption apparatus and a GC system equipped with two detectors, i.e. PID and ECD. Preliminary tests conducted to check out any contamination of the system revealed an evidence of significant artifact formation of benzene, and it was found that the Nafion dryer (even brand new one) is the source of the benzene artifact. Thus, all the subsequent experiments in this study was carried out inevitably by removing the Nafion dryer. The on-line GC method was investigated with a variety of QC/QA performance criteria such as repeatability, linearity, lower detection limits, and accuracy. In order to find out the best operating condition for the on-line GC system, three different types (in terms of adsorption strength) of cold trap combinations were tested, i.e. (i) Tenax-TA and Carbopack-B combination (weak and hydrophobic); (ii) Tenax-TA, Carbopack-X and Carboxen-1000 combination (strong and hydrophilic); and (iii) Tenax-TA and Carbopack-X combination (medium and hydrophobic/hydrophilic). The USEPA TO-17 manual method was selected as a reference method to evaluate the performance of the on-line method. A series of experiments revealed that the system performance was superior to others when a cold trap packed with hydrophilic adsorbents (Tenax-TA/Carbopack-X/Carboxen-1000 combination) was used and operated at $25^{\circ}C$. However, the system with a cold trap packed with a combination of Tenax-TA and Carbopack-X is more recommended for field applications since the carboxen-1000 adsorbent is too sensitive to water vapor, and hence the performance of the system might be very unstable to humid samples or during rainy days. Furthermore, the precision and accuracy criteria of the Tenax-TA/ Carbopack-X combination were generally compatible with the triple adsorbents cold trap. The continuous automatic monitoring method is, thus, considered very useful to real-time monitoring to understand the variations of VOCs concentrations in ambient air, as it adopts much simpler procedures in sampling, analysis, and data integration steps than manual monitoring methods. However, it should be noted that there is a high possibility of benzene artifacts formation through the Nafion dryer, which is often installed to remove water vapor in air samples before being adsorbed onto the cold trap. Therefore, if a Nafion dryer is used in any studies of monitoring VOCs, the benzene contamination should be carefully examined before carrying out obtaining the data.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.307-316
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• 2013

The sensitivity of ozone to $NO_x$ and volatile organic compounds (VOCs) emission rates under different ventilation rates and $NO_2-to-NO_x$ emission ratios in a street canyon is investigated using a chemistry box model. The carbon bond mechanism IV (CBM-IV) with 36 gaseous species and 93 chemical reactions is incorporated. $NO_x$ and VOCs emission rates considered range from 0.01 to $0.30ppb\;s^{-1}$ with intervals of $0.01ppb\;s^{-1}$. Three different ventilation rates and three different $NO_2-to-NO_x$ emission ratios are considered. The simulation results show that the ozone concentration decreases with increasing $NO_x$ emission rate but increases with increasing VOCs emission rate. When the emission ratio of VOCs to $NO_x$ is smaller than about 4, the ozone concentration is lower in the street canyon than in the background. On average, the magnitude of the sensitivity of ozone to $NO_x$ emission rate is significantly larger than that to VOCs emission rate. As the $NO_x$ emission rate increases, the magnitude of the sensitivity of ozone to $NO_x$ and VOCs emission rates decreases. Because the ozone concentration is lower in the street canyon than in the background, the increased ventilation rate enhances ozone inflow from the background. Therefore, the increase in ventilation rate results in the increase in ozone concentration and the decrease in the magnitude of the sensitivity of ozone to $NO_x$ and VOCs emission rates when the emission ratio of VOCs to $NO_x$ is smaller than about 4. On the other hand, the increase in $NO_2-to-NO_x$ emission ratio results in the increase in ozone concentration because the chemical ozone production due to the $NO_2$ photolysis is enhanced. In the present experimental setup, the contribution of the change in $NO_2-to-NO_x$ emission ratio to the change in the sensitivity of ozone to $NO_x$ emission rate is larger than that of the change in ventilation rate.

• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.300-312
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• 2017

To improve the understanding of secondary organic aerosol (SOA) formation from the photo-oxidation of anthropogenic and biogenic precursors at the regional background station on Baengnyeong Island, Korea, gas phase and aerosol chemistries were investigated using the Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS) and the Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS), respectively. HR-ToF-AMS measured fine particles ($PM_1$; diameter of particle matter less than $1{\mu}m$) at a 6-minute time resolution from February to November 2012, while PTR-ToF-MS was deployed during an intensive period from September 21 to 29, 2012. The one-minute time-resolution and high mass resolution (up to $4000m{\Delta}m^{-1}$) data from the PTR-ToF-MS provided the basis for calculations of the concentrations of anthropogenic and biogenic volatile organic compounds (BVOCs) including oxygenated VOCs (OVOCs). The dominant BVOCs from the site are isoprene (0.23 ppb), dimethyl sulphide (DMS, 0.20 ppb), and monoterpenes (0.38 ppb). Toluene (0.45 ppb) and benzene (0.32 ppb) accounted for the majority of anthropogenic VOCs (AVOCs). OVOCs including acetone (3.98 ppb), acetaldehyde (2.67 ppb), acetic acid (1.68 ppb), and formic acid (2.24 ppb) were measured. The OVOCs comprise approximately 75% of total measured VOCs, suggesting the occurrence of strong oxidation processes and/or long-range transported at the site. A strong photochemical aging and oxidation of the atmospheric pollutants were also observed in aerosol measured by HR-ToF-AMS, whereby a high $f_{44}:f_{43}$ value is shown for organic aerosols (OAs); however, relatively low $f_{44}:f_{43}$ values were observed when high concentrations of BVOCs and AVOCs were available, providing evidence of the formation of SOA from VOC precursors at the site. Overall, the results of this study revealed several different SOA formation mechanisms, and new particle formation and particle growth events were identified using the powerful tools scanning mobility particle sizer (SMPS), PTR-ToF-MS, and HR-ToF-AMS.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.648-653
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• 2006

As an alternative for the traditional materials packed in biofilters treating gaseous VOCs, a novel packing material has been developed and tested. In the packing material(named as Hydrogel Bead, HB), pollutant-degrading microorganisms were immobilized in hydrogel consisted of alginate, polyvinyl alcohol(PVA), and powdered activated carbon. A closed-bottle study showed that the HB rapidly removed gaseous styrene without the losses of adsorption and biodegradation capacity. Biofilter column experiments using the HBs also demonstrated that greater than 95% of removal efficiencies were found at an inlet styrene loading rate of $245g/m^3/hr$, which was higher biofilter performance than other elimination capacity reported earlier. Furthermore, when the inlet styrene concentration increased stepwise, the adsorption played an important role in overall styrene removals. The absorbed styrene was found to be biodegraded in the following low inlet loading condition. Consequently, the new HB material is able to successfully minimize the drawbacks of activated carbon(necessity of regeneration) and biological processes(low removal capacity at dynamic loading conditions), and maximize the overall performance of biofilter systems treating VOCs.