• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.242.2-242.2
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• 2011

Molecularly imprinted polymer thin films were applied to develop a gas sensor based on the surface plasmon resonance phenomenon for small gaseous molecules such as toluene and xylene. The imprinted polymer films were synthesized via photo-polymerization method using various combination of templates, functional monomers and cross-linkers. The temperature of pre-polymerization solutions and the power of UV light were controlled for optimized performance of gas sensing. The morphology and porosity of the polymer films were controlled by varying the mixing ratios of the pre-polymerization solutions and confirmed by atomic force microscopy. By fitting the adsorption/desorption sensorgrams to conventional kinetic models, the effects of different templates and cross-linkers were interpreted in term of the structural differences of the polymer networks formed on the gold film. The sensitivity and selectivity of sensors were estimated for toluene and xylene, and also for humidity and other gaseous molecules such as formaldehyde and ammonia.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.34-34
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• 2010

Activities of various $TiO_2$ nanostructures in photocatalytic decomposition of methylene blue and toluene were determined in order to shed light on the relationship between structures and photocatalytic activity. Commercially available P-25 samples were used in the present work. In addition, $TiO_2$ nanostructures were synthesized using atomic layer deposition (ALD). We show that change in the surface structure of $TiO_2$ upon variois surface treatments results in variation in photocatalytic activity. In particular, increase in the number of OH groups on the surface leads to the enhancement in photocatalytc activity. Surface OH groups increases adsorption reactivity of organic reactants, thereby increasing activity in photocatalytic decomposition of methylene blue and toluene.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.784-790
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• 2010

VOCs such as acetone, benzene, toluene, ethylbenzene were adsorbed in a fixed-bed adsorber using zeolite synthesized from coal fly ash and 4 kinds of activated carbon at 101.3 kPa. The adsorber was operated batchwise with the charge of 5 g adsorbent to obtain the breakthrough curve of VOCs. Experiments were carried out at $40^{\circ}C$, nitrogen flow rate of $70cm^3/min$ and sparger temperature of $30^{\circ}C$. The deactivation model was tested for these curves by combining the adsorption of VOCs and the deactivation of adsorbent particles. The observed values of the adsorption rate constant and the deactivation rate constant were evaluated through analysis of the experimental breakthrough data using a nonlinear least square technique. The experimental breakthrough data were fitted very well to the deactivation model than the adsorption isotherm models in the literature. Also, adsorption capacities of adsorbents were obtained from the breakthrough curve to observe the correlation between adsorption capacity and the physical properties of VOCs.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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• pp.78-84
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• 1995

Cationic surfactants can be used to modify surface of solids to promote adsorption of hydrophobic organic compounds. This behavior is due to the surfactant forming aggregate structure on the solid surface. Partition coefficients are commonly used to quantify the distribution of organic pollutants between the aqueous and particulate phases of aquatic system Partitioning of hydrophobic compounds to cetyltrimethylammonium bromide ( CTAB ) coated silicate has been investigated as a function of surfactant surface coverage at I=0 and 0.1 ionic strength. Toluene, Xylene, TCI sorption experiments demonstrated that the CTAB coated silicate was able to remove these hydrophobic organic compounds from solution The hydrophobic organic compound with the higher Kow had higher removals than lowest Kow hydrophobic organic compound.

• Journal of Environmental Science International
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• v.13 no.1
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• pp.41-45
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• 2004

In this study, The decomposition of gas-phase Benzene and Toluene, Xylene in air streams by direct UV Photolysis, UV/TiO$_2$ and UV/TiO$_2$/A.C process was studied. The experiments were carried out under various UV light intensities and initial concentrations of B.T.X to investigate and compare the removal efficiency of the pollutant. B.T.X was determined by GC-FID of gas samples taken from the a glass sampling bulb which was located at reactor inlet and outlet by gas-tight syringe. From this study, the results indicate that UV/TiO$_2$/A.C system (photooxidation-photocatalytic oxidation-adsorption process) is ideal for treatment of B.T.X from the small workplace. Although the results needs more verifications, the methodology seems to be reasonable and can be applied for various workplace (laundry, gas station et al.).

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.76-83
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• 2000

This research is about wastewater containing non-biodegradable TDI(Toluene Diisocyanate) that is treated by the activated carbon adsorption method. In the case of the Fenton oxidation process being applied to the existing process, optimal pH, reaction time, chemical dosing amount, removal rate, and cost were investigated. A pilot plant test was applied after finding optimal conditions with lab experiments. The optimal conditions were pH 3~5(COD removal rate 84~88%) and reaction time 30min~1hr. In higher $H_2O_2$ dosing amount, COD removal rate was a little higher. But there was little difference in the removal rate according to $FeSO_4{\cdot}7H_2O$ dosing amount. Treatment cost was economical in the case of the Fenton oxidation process being operated earlier than activated carbon adsorption system. But chemical dosing point, chemical mixing effect, chemical dosing amount, removal rate, and the cost of facility and others must be considered in practical process.

• Carbon letters
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• v.1 no.2
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• pp.82-86
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• 2000

The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.529-532
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.415-416
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• 2000

플라즈마 화학공정을 이용한 유해대기오염물질(HAP$_{s}$ 또는 VOC$_{s}$ ) 처리기술은 기존의 촉매연소, 소각 및 흡착기술등에 비하여 낮은 초기 투자비, 여러가스의 동시처리, 소형화 또는 이동 배출원에 대한 적용이 가능하며, 대상가스의 종류나 발생량등에 따라 여러 전원(AC, Pulse, DC)을 이용한 기술개발이 가능하여 많은 연구가 진행되고 있다.$^{(1-4)}$ (중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.257-257
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• 2013

In order to selectively remove oil and organic compound from water, silica nanoparticles with hydrophobic coating was used. Since silica nanoparticles are generally hydrophilic, removal efficiency of oil and organic compound, such as toluene, in water can be decreased due to competitive adsorption with water. In order to increase the removal efficiency of oil and toluene, hydrophobic polydimethylsiloxane (PDMS) was coated on silica nanoparticles in the form of thin film. Hydrophobic property of the PDMS-coated silica nanoparticles and hydrophilic silica nanoparticles were easily confirmed by putting it in the water, hydrophilic particle sinks but hydrophobic particle floats. PDMS coated silica nanoparticles were dispersed on a slide glass with epoxy glue on and the water contact angle on the surface was determined to be over $150^{\circ}$, which is called superhydrophobic. FT-IR spectroscopy was used to check the functional group on silica nanoparticle surface before and after PDMS coating. Then, PDMS coated silica nanoparticles were used to selectively remove oil and toluene from water, respectively. It was demonstrated that PDMS coated nanoaprticles selectively aggregates with oil and toluene in the water and floats in the form of gel and this gel remained floating over 7 days. Furthermore, column filled with hydrophobic PDMS coated silica nanoparticles and hydrophilic porous silica was prepared and tested for simultaneous removal of water-soluble and organic pollutant from water. PDMS coated silica nanoparticles have strong resistibility for water and has affinity for oil and organic compound removal. Therefore PDMS-coated silica nanoparticles can be applied in separating oil or organic solvents from water.