• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.49-56
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• 2018

BACKGROUND: The mobile vortex wet scrubber was developed to remove the harmful chemicals from accidental releases. However, there was a disadvantage that it was limitedly used for volatile organic compounds (VOCs) such as toluene according to the physicochemical properties. This study compared the removal efficiencies of an improved mobile scrubber on toluene and ammonia by applying diverse adsorption and absorption methods. METHODS AND RESULTS: The removal efficiencies on harmful chemicals were examined using various adsorption and absorption methods of water vortex process (C), phosphoric acid-impregnated activated carbon adsorption (PCA), pH-controlled water (pH 2.5) vortex process absorption with sulfuric acid (SWA) after ammonia exposure, granular activated carbon adsorption (GCA), and activated carbon mat adsorption (CMA) after toluene exposure. As a result, the best removal efficiency was shown in the SWA for ammonia and GCA for toluene. Also, the SWA and GCA methods were compared with different concentration levels. In the case of ammonia exposure (5, 10 and 25%), there was no difference by concentration levels, and the concentration in the outlet gradually increased, with pH change from acid to base. In the case of toluene exposure (50, 75 and 100%), the outlet concentration was higher relative to the exposure concentration in the initial 10 min, but the outlet concentration was remained steady after 10 min. CONCLUSION: The newly improved mobile scrubber was also effective in removing VOCs through adsorption techniques (activated carbon, activated carbon fiber, carbon mat filter etc.), as well as removing acid-base harmful chemicals by neutralization reaction.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.1
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• pp.72-80
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• 1999

Separation of VOCs(Volatile Organic Compounds) in Water Using Activated Carbon is known to be effective. Activated Carbon has been and will be employed in many water treatment plants. Simplified plug flow homogeneous surface diffusion model(PFHSDM) has been used to predict adsorption of organic matter. Finite Element Method(FEM) was used to analyze the model. Out of water quality control substances, benzene, toluene and tetrachloroethylene were used in the small column test. Film diffusion coefficients and surface diffusion coefficients were obtained from the column test, and were compared with the modeling results. Mc Cune, Williamson, William and Kataoka model, were compared with film diffusion coefficients obtained in the test. McCune model was fitted best for those VOCs used in this experiment. Film diffusion coefficients of VOCs obtained were benzene 0.265 cm/min, toluene 0.348 cm/min and tetrachloroethylene 0.298 cm/min. Surface diffusion coefficients of VOCs obtained were benzene $6.36{\times}10^{-8}cm^2/min$, toluene $3.20{\times}10-8cm2/min$, and tetrachloruethylene $4.94{\times}10^{-8}cm^2/min$.

• Clean Technology
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• v.8 no.2
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• pp.93-99
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• 2002

Adsorption dynamics for toluene and trichloroethylene with an isothermal fixed bed of activated carbon fiber were investigated. Equilibrium isotherms were measured by a static method for toluene and trichloroethylene onto activated carbon fiber at temperatures of 298, 323, and 348 K and pressure up to 3 kPa for toluene and 6 kPa for trichloroethylene, respectively. These results were correlated by the Toth equation. And dynamic experiments in an isothermal condition of 298 K were examined. Breakthrough curves reflected the effects of the experimental variables such as partial pressures for adsorbate and interstitial bulk velocities of gas flow. To present the column dynamics, a dynamic model based on the linear driving force (LDF) mass transfer model was applied.

• KSBB Journal
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• v.13 no.4
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• pp.449-455
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• 1998

The bacterial motility in sand was studied with Alcaligenes xylosoxidans Y234 which is known as a strong decomposer of aromatic chemicals, especially toluene. Apparent motility coefficient (${\mu}$c,app) and apparent chemotaxis coefficient (${\mu}$c,app) for toluene were measured in the sands which have four different porosities. Adsorption ratio of Alcaligenes xylosoxidans Y234 on the sands was measured as 17%. The ramdom motility coefficients were 0.85∼1.68${\times}$10-3$\textrm{cm}^2$/sec, and decreased as the porosity of sands decreased. Apparent chemotaxis coefficients were measured as 1.1∼6.8${\times}$10-5$\textrm{cm}^2$/sec, and decreased as the porosity decreased and with time. The tendency of alcaligenes xylosoxidans Y234 movement towards toluene seemed very weak and showed little chemotaxis.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.04a
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• pp.307-312
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• 2000

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.64-73
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• 2007

The catalytic activity of transition metals (Cu, Co, Mn, Fe and Ni) supported on ${\gamma}-Al_2O_3$ for the oxidation of toluene was investigated in the microreactor of fixed-bed type. The catalytic activity of transition metals for the oxidation of toluene turned out to be increasing in the order of Ni$Cu/{\gamma}-Al_2O_3$ catalysts for the oxidation of toluene increased with the increasing loadings of copper, reached the maximum activity at 5% loadings of copper, and decreased with higher loadings of copper in the catalysts. The activity of $Cu/{\gamma}-Al_2O_3$ catalysts for the oxidation of toluene decreased with the increasing calcination temperatures. This might result from the decreasing surface area of catalysts due to the sintering of copper oxide as well as ${\gamma}-Al_2O_3$ supports. The 5wt% $Cu/{\gamma}-Al_2O_3$ catalysts calcined at $400^{\circ}C$ for 4 hrs in the air showed the highest activity for the oxidation of toluene. Mutual inhibition was observed for the binary mixture of toluene and xylene. The activity of the easy-to-oxidize toluene was greatly decreased while the difficult-to-oxidize xylene was slightly decreased in the binary mixture of toluene and xylene. It might suggest that the inhibition of toluene and xylene in the binary mixture resulted from the competitive adsorption for the adsorbed oxygen on the catalytic surface.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.456-461
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• 2007

This study was carried out two point view that reuse of sludge and adsorption of benzene, toluene and o-xylene of VOCs in cast, carbonized cast and activated carbon. The cation exchange capacity of cast and carbonized cast were 59.2, 112 meq/100g, respectively. The specific surface were 560, $800m^2/g$, respectively. The average removal rates of benzene by 50g cast of 50% hydrous cast, anhydrous cast, carbonized cast, activated carbon were 15.0, 41.2, 88.2, 99.4% in 60min of retention time. The average removal efficiency of toluene by 50 g cast of 50% hydrous cast, anhydrous cast, carbonized cast, activated carbon were 12.5, 34.2, 88.2, 99.5% in 60 min of retention time. The average removal rates of o-xylene 50 g cast of 50% hydrous cast, anhydrous cast, carbonized cast, activated carbon were 8.8, 28.5, 84.8, 98.1% in 60min of retention time. The adsorption efficiency of test absorbent was in order of Activated Carbon > Carbonized Cast > Cast.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.205-210
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• 2000

VOC는 volatile organic compound의 약자로서 toluene, benzene, MEK, MIBK등 자동차 운행, 도장산업, 인쇄업, 대형 세탁시설, 유류저장 및 출하시설에서 주로 배출되는 유기성 배기배출물을 총칭하는 개념이다. VOC는 작업현장에서 악취를 발생시켜 작업현장에서의 쾌적성을 해치기도 하지만, 태양에너지를 받아 오존을 형성하기 때문에 인체에 크게 해로운 역할을 한다. 정부에서는 대기환경보전법을 제정하여 휘발성유기화합물질 배출억제 정책을 실시하고 있으며, 배출업소에 대하여 휘발성유기화합물질 방지시설 설치를 의무화하고 있다.(중략)

• Clean Technology
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• v.27 no.2
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• pp.160-167
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• 2021

This study investigated the environmental effects of improving the general-type activated carbon adsorption tower used at the Sihwa/Banwol Industrial Complex with use of a cartridge-type activated carbon adsorption tower for the application of an activated carbon co-regenerated system. Four general-type activated carbon adsorption towers and two cartridge-type activated carbon adsorption towers were selected to analyze the properties of activated carbon and to compare the efficiency of reducing environmental pollutants. The results showed that the activated carbon used in the cartridge-type activated carbon adsorption towers was high quality activated carbon with an iodine adsorption force of more than 800 mg/g and that a good adsorption performance was maintained within the replacement cycle. From an analysis of the environmental pollutant reduction efficiency, it was confirmed that the cartridge-type activated carbon adsorption tower functioned properly as a prevention facility for handling emissions pollutants with a treatment efficiency of total hydrocarbons (THC), toluene, and methylethylketone (MEK) components of 71%, 77%, and 80%, respectively. The general activated carbon adsorption tower, which was confirmed to use low-performance activated carbon, had a very low treatment efficiency and did not function properly as a prevention facility for dealing with emission pollutants. It is believed that it is possible to reduce pollutants during operations by changing from the general-type activated carbon adsorption tower to a cartridge-type activated carbon adsorption tower.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.239-247
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• 2016

This study aims to examine absorption characteristics of toluene, isopropyl alcohol (IPA), ethyl acetate (EA), and ternary-compounds, all of which are widely used in industrial processes, by means of four types of commercial activated carbon substances. It turned out that among the three types of volatile organic compounds, the breakthrough point of activated carbon and that of IPA, whose affinity was the lowest, were the lowest, and then that of EA and that of toluene in the order. With the breakthrough point of IPA, which was the shortest, as the standard, changes in the breakthrough points of unary-compounds, binary-compounds, and ternary-compounds were examined. As a result, it turned out that the larger the number of elements, the lower the breakthrough point. This resulted from competitive adsorption, that is, substitution of substances with a low level of affinity with those with a high level of affinity. Hence, the adsorption of toluene-IPA-EA and ternary-compounds require a design of the activated carbon bed based on the breakthrough of IPA, and in the design of activated carbon beds in actual industries as well, a substance whose level of affinity is the lowest needs to be the standard.