• 한국환경과학회지
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• 제15권7호
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• pp.695-699
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• 2006

This study is to investigate the relationship between pore structures of activated carbons and adsorption characteristics of toluene vapor using dynamic adsorption method. The surface areas of below $10{\AA}$ in the pore diameter of activated carbons used in this experiment were in the range of 72 -93 % of total cumulative surface area and the toluene vapor equilibrium adsorption capacities were in the range of 350 - 390mg/g. Activated carbons having larger toluene adsorption capacity than the compared activated carbons had relatively pores in the pore diameter range of $7-10{\AA}$. Linear relationship between equilibrium adsorption capacity and cumulative sur- face area was in the diameter range of over $7{\AA}$. It was thought that toluene vapor was relatively well adsorbed on surfaces of pores of over $7{\AA}$.

• 대한환경공학회지
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• 제27권8호
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• pp.807-812
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• 2005

연속식 흡착장치를 사용하여 산처리로 세공구조를 변화시킨 Zeolite 5A의 toluene vapor 평형흡착량과 흡착제의 세공직경에 따른 표면적과의 상관관계를 고찰하였다. 산처리에 의해 미세세공이 형성되기도 하지만 기존 미세세공의 직경이 점차 확대되었으며, 산의 농도가 높을수록 미세세공이 중간세공 이상으로의 변화가 많았다. 산처리한 Zeolite 5A의 toluene vapor 평형흡착량은 $15{\sim}\;mg/g70$ 사이였고 산처리에 의해 평형흡착량이 약 5배까지 증가하였으며, toluene vapor는 주로 직경 $15\;{\AA}$ 이상의 세공 표면적에 비교적 잘 흡착되는 것으로 판단되었다. Toluene vapor 평형흡착량과 총 누적표면적(total cumulative surface area)은 상관관계가 없었으며, 직경 $15\;{\AA}$ 이상의 누적표면적과는 가장 높은 상관관계(0.997)를 나타내었다.

• 한국환경과학회지
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• 제24권3호
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• pp.317-322
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• 2015

The photocatalytic decomposition characteristics of toluene, acetone, and methyl mercaptan (MM) by UV reactor installed with $TiO_2$-coated perforated plane were studied. The removal efficiency of single toluene, acetone, and MM vapor was increased with increasing oxygen concentration, but decreased with increasing inlet concentration. Elimination capacity of single toluene, acetone, and MM vapor was obtained to be $628g/m^3{\cdot}day$, $1,041g/m^3{\cdot}day$, and $2,158g/m^3{\cdot}day$, respectively. Also, the photocatalytic decomposition of binary vapor consisted of toluene and acetone, toluene and MM, acetone and MM were observed. Elimination capacity of toluene mixed with acetone, toluene mixed with MM, acetone mixed with toluene, acetone mixed with MM, MM mixed with toluene, and MM mixed with acetone was $327g/m^3{\cdot}day$, $512g/m^3{\cdot}day$, $128g/m^3{\cdot}day$, $266g/m^3{\cdot}day$, $785g/m^3{\cdot}day$ and $883g/m^3{\cdot}day$, respectively. The inhibitory effect of acetone was higher than MM in photocatalytic decomposition of toluene, the inhibitory effect of toluene was higher than MM photocatalytic decomposition of acetone, and the inhibitory effect of toluene was higher than acetone in photocatalytic decomposition of MM.

• 한국환경과학회지
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• 제21권10호
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• pp.1195-1202
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• 2012

The purpose of this work is to study the adsorption and desorption characteristics of acetone vapor and toluene vapor from adsorption tower in the VOCs recovery device. The six kinds of activated carbon with different pore structures were used and the adsorption and desorption characteristics were compared according to pore structure, desorption temperature, and adsorption method, respectively. Adsorption capacity of acetone vapor and toluene vapor by batch method was higher than that by dynamic method. Especially, activated carbon with medium-sized or large pores had more difference in adsorption capacity according to adsorption methods as a result of gradually condensation of vapors on relatively mesopore and large pores. Activated carbons with relatively large pores and relatively small saturated adsorption capacity had excellent desorption ability.

• 한국대기환경학회지
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• 제14권6호
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• pp.599-606
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• 1998

Removal of toluene vapor from airstreams was studied in a biological reactor known as a biofilter. The biofilter was packed porous ceramic inoculated with thickened activated sludge (MLVSS 17,683 mg/L). The lab-scale biofilter was operated for 42 days under various experimental conditions including inlet toluene concentrations and flow rates of the contaminated air streams. Removal efficiency reached up 96.6% after 4 days from start up. Nutrient limitation was proposed as a reason for the decrease in biofilter performence. Biofilter performance decreased substantially, coincident with the buildup of back pressure due to accumulation of excess VSS within the medium bed. Practically, the bed needs to be backwashed when the overall pressure drop is greater than 460.6 Pa at SV (Space Velocity) 100 h-1. Periodic backwashing of the biofilter was necessary for removing excess biomass and attaining stable long -term high removal efficiency The removal efficiency of toluene in the biofilter decreased as the gas velocity and toluene concentration in the inlet gas increased. The maximum elimination capacity of ceramic biofilter could reach up to 444.85 g/m3. hr. When the loading of toluene exceed this critical value, substrate inhibition occurred.

• 한국환경과학회지
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• 제23권12호
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• pp.1971-1976
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• 2014

In this study, the photocatalytic decomposition characteristics of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed methyl mercaptan (MM) by UV reactor installed with $TiO_2$-coated perforated plate were studied. The photocatalytic decomposition rate of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed with MM fitted well on Langmuir-Hinshelwood (L-H) kinetics equation. The maximum elimination capacity was obtained to be $628g/m^3{\cdot}d$ for single toluene, $499g/m^3{\cdot}d$ for toluene mixed with benzene, $318g/m^3{\cdot}d$ for toluene mixed with acetone, and $513g/m^3{\cdot}d$ for toluene mixed with MM, respectively. The negative effect in photocatalytic decomposition of toluene are found to be in the order of acetone>benzene>MM.

• 한국산업보건학회지
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• 제6권1호
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• pp.55-66
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• 1996

This study was conducted to evaluate breakthrough characteristics of respirator cartridge using multi-organic vapors, including carbon tetrachloride, trichloroethylene, and toluene. The organic vapors were used as single phase, binary system, and ternary system. The results are summarized as follows. 1. Organic vapors studied were 1,000 ppm, 750 ppm, 500 ppm and 250 ppm in single phase. Carbon tetrachloride having the highest molecular weight showed the breakthrough first, and breakthrough sequency by organic vapor was dependent on its molecular weight. The 10% breakthrough times at 1,000 ppm of organic vapor were 97 minutes for carbon tetrachloride, 129 minutes for trichloroethylene and 135 minutes for toluene. 2. When concentrations of organic vapors were at levels of the Threshold Limit Values, the lives of the respirator cartridges were 122 hours in carbon tetrachloride, 18 hours in trichloroethylene and 28 hours in toluene. 3. In the binary system at a total concentration of 1,000 ppm with carbon tetrachloride and trichloroethylene, breakthrough times ranged from 104 minutes to 125 minutes, which were longer than 97 minutes in a single phase (1,000 ppm) for carbon tetrachloride, but shorter than breakthrough times for TCE and Toluene. 4. Breakthrough times in the binary system with carbon tetrachloride and toluene were 131~132 minutes. 5. Breakthrough times in the ternary system with carbon tetrachloride, toluene, and trichloroethyl ene were $120{\pm}8$ minutes, which were longer than 97 minutes in the single phase (1,000 ppm) for carbon tetrachloride, equal to 129 minutes for trichloroethylene, and shorter than 135 minutes for toluene. Those were almost similar to $124{\pm}9$ minutes of breakthrough times in the binary systems.

• 한국막학회:학술대회논문집
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• 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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• pp.23-26
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• 1999

Urethane block copolymers, containing soft segments such as polydimethylsiloxane (PDMS), polytertramethylene glycol(PTMG) and PEO-PPO-PEO (Poloxamer) block copolymer, were synthesized and examined for th vapor- phase separation of toluene from nitrogen stream by using vapor permeation equipment. Generally permeabilities of PTMG and PDMS based urethane membranes were higher than those of Poloxamer based urethane membranes. Organic vapor permeability in the PDMS and PTMG soft segment urethane membranes were greater than those measured in the Poloxamer films, due to more polymer swelling. The membranes performed best with toluene, with toluene/dry N2 seletivities ranging from 120~200 and permeablilities as high as 23$\times$10-9 mol/m2sPa for saturated toluene feeds at 23$^{\circ}C$.

• 한국환경과학회지
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• 제14권1호
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• pp.61-69
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• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

• 대한환경공학회지
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• 제30권11호
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• pp.1161-1169
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• 2008

생물학적 처리방법인 biofiltration을 이용하여 1차 기질 toluene의 존재여부에 따른 TCE와 PCE의 제거율을 비교하였다. 그리고 TCE와 PCE의 제거과정에 관련된 미생물의 군집변화를 조사하였다. TCE와 PCE혼합증기 제거율을 순치시킨 슬러지를 메디아 표면에 부착한 biofilter B를 이용해서 1차 기질로서 toluene증기 공급이 없는 상태에서 TCE/PCE 혼합증기제거율을 조사하고 또한 toluene증기로 순치시킨 슬러지를 부착한 별도의 biofliter A에서 1차 기질로서 toluene증기를 공급하는 상태에서 TCE/PCE 혼합증기의 제거율을 조사한 결과 (i) biofilter운전초기에는 PCE제거율이 TCE제거율보다 현저히 높지만, biofilter운전 지속기간의 증가에 따라 두 물질의 제거율이 증가하다가 나중에는 두 가지 물질의 제거수준이 비슷해진 상태에서 정체되는 경향이 있고, 1차 기질로서 toluene증기를 공급하지 않은 경우가 공급한 경우보다 현저히 TCE/PCE 제거율이 높으며, 두 물질의 생물여과에 의한 제거율이 동등수준에 도달하는 시간이 1차 기질을 공급하는 경우에 공급하지 않는 경우보다 빠르게 도달하였다. 이 실험은 (ii)일부의 toluene 분해 미생물이 TCE와 PCE 증기 등 염소화 휘발성 유기물 증기의 분해에도 관여하고, TCE/PCE 증기의 생물학적 저감과정에서 공동대사가 반드시 필요하지는 않는 것임을 시사한다. DGGE밴드의 16S rDNA의 염기서열을 결정한 결과 (i) uncultured alpha proteobacterium, uncultured Desulfitobacterium sp., uncultured Rhodobacteraceae bacterium, Cupriavidus necator, Pseudomonas putida 등이 toluene 분해 미생물들이었고 (ii) alpha proteobacterium HTCC396이 TCE 제거미생물이고, (iii) Desulfitobacterium sp.이 PCE 분해에 관여하는 것으로 추정된다. (iv) 특히 uncultured Desulfitobacterium sp.은 toluene뿐만 아니라 다양한 염소계 화합물을 제거시킬 수 있는 미생물임이 확인되었다.