• Applied Chemistry for Engineering
• /
• v.32 no.6
• /
• pp.627-631
• /
• 2021

Research on induction heating catalyst system was conducted to solve problems of the existing catalyst system for removing volatile organic compounds. In the present study, three types of Ni-based commercial catalysts were employed, and induction heating reaction characteristics including the catalyst volume, composition, heat treatment atmosphere, and position in the coil were investigated. The composition and volume of the catalyst affected the exothermic and toluene oxidation performance in the induction heating system. In particular, the Fe-added catalyst showed high exothermic performance compared to that of other catalysts consisting of more than 99% Ni, but had low toluene oxidation performance. In addition, the heat treatment in an air atmosphere of the Ni-based catalyst drastically reduced the performance. In the induction heating system, the optimal condition for the catalyst was to be located in the center of the coil. The catalyst showed similar activities among seven repeated experiments under the optimal condition derived from this work.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.2
• /
• pp.113-119
• /
• 1999

In this study, the incineration of MEK and toluene was studied on a Pt supported alumina catalyst at temperature range from 200 to $350^{\circ}C$. An approach based on the Mars-van Krevelen rate model was used to explain the results. The object of this study was to study the kinetic behavior of the platinum catalyst for deep oxidation. The conversions of MEK and toluene were increased as the inlet concentration was decreased and the reaction temperature was increased. The maximum deep conversion of MEK and toluene were 91.81% and 55.69% at $350^{\circ}C$, respectively. The ${\kappa}_3$ constant increases with temperature faster than the ${\kappa}_1$ constant, that is, the surface concentration of ($VOCs{\cdots}O$) is higher than that of (O) at higher temperature according to the Mars-van Krevelen mechanism. Also the activation energy of toluene was larger than MEK for toluene is aromatic compound which have stronger bonding energy.Therefore, the catalytic incineration kinetics of MEK and toluene with Mars-van Krevelen mechanism could be used as the basic data for industrial processes.

• Clean Technology
• /
• v.14 no.4
• /
• pp.271-274
• /
• 2008

In this work, the feasibility of spent zeolite catalyst for reusing as a support was investigated in catalytic odor removal reaction. As a model reaction for odor removal, toluene was selected as a reactant. 10wt% Cu was impregnated on spent HZSM-5 catalyst and spent FCC catalyst. The catalytic activity of the spent HZSM-S was higher than that of spent FCC catalyst in toluene oxidation. This was due to the fact that the surface area of spent HZSM-S was higher than that of spent FCC catalyst. These results may suggest that spent HZSM-S can be reused as a cheap catalyst for toluene removal.

• Journal of environmental and Sanitary engineering
• /
• v.16 no.4
• /
• pp.69-76
• /
• 2001

The catalytic oxidation of volatile organic compounds (VOCs), which were benzene and toluene, was studied in the supercritical carbon dioxide($SC-CO_2$) media. In $SC-CO_2$ media, the deep oxidation conversion of VOCs was increased with the temperature and pressure. The deep oxidation conversion in SC -$CO_2$ media is better than that in air media at same pressure condition. This can be explained by the solubility of VOCs in $SC-CO_2$. The many intermediates produced by the partial oxidation of VOCs were detected from off-line samples. The intermediates were Identified as benzene, toluene, benzaldehyde, phenol, naphthalene, 1,1`-biphenyl, benzoic acid, 3-methylphenol, 1,1'-(1,2-ethanediyl)bis- benzene, 1,1'-(1,2-ethene- diyl)bis-benzene, anthracene, and so on. The amount of intermediates was decreased as the molar radio of oxygen to carbon dioxide was decreased. When the molar ratio of oxygen to carbon dioxide was 1 : 16, the deep conversion was kept constant. Thus, the catalytic oxidation process in $SC-CO_2$ media can be combined on-line with supercritical fluid extraction of environmental matrices and supercritical regeneration of used adsorbent. Thus, the nontoxic $SC-CO_2$ media process was suggested as the new VOCs control technology.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.128-128
• /
• 2013

Fabrication of heterogeneous catalysts using Atomic Layer Deposition (ALD) has recently been attracting attention of surface chemists and physicists. In this talk, I will present recent results about structures and chemical activities of various catalysts prepared by ALD, particularly focusing on Ni-based catalysts. Ni has been considered as potential catalysts for $CO_2$ reforming of methane (CRM); however, Ni often undergoes rapid decrease in catalytic activity with time, and therefore, application of Ni as catalysts for CRM has been regarded as difficult so far. Deactivation of Ni catalysts during CRM reaction is from either coke formation on Ni surface or sintering of Ni particles during reaction. Two different strategies have been used for enhancing stability of Ni-based catalysts; $TiO_2$ nanoparticles were deposited on micrometer-size Ni particles by ALD, which turned out to reduce coke formation on Ni surfaces. Ni nanoparticles deposited by ALD on mesoporous silica showed high activity and long-term stability from CRM without coke deposition and sintering during CRM reaction. Ni-based catalysts have been also used for oxidation of toluene, which is one of the most notorious gases responsible for sick-building syndrome. It was shown that onset-temperature of Ni catalysts for toluene oxidation is as low as $120^{\circ}C$. At $250\circ}C$, total oxidation of toluene to $CO_2$ with a 100% conversion was found.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.5
• /
• pp.663-670
• /
• 2004

The catalytic oxidation of benzene, toluene and xylene over a spent industrial catalyst (Pd-based) was investigated in a fixed bed flow reactor system. According to the priming condition, the properties of a spent Pd-based catalyst were characterized by XRD(X-ray diffraction). BET(Brunauer-Emmett-Teller) and ICP(Inductively coupled plasma). When air was used as a primer, optimum priming temperature was found to be 200$^{\circ}C$, and the catalytic activity decreased as the priming temperature increased. When a spent Pd-based catalyst primed with air at 200$^{\circ}C$ was re-treated with hydrogen at 200$^{\circ}C$, 300$^{\circ}C$ or 400$^{\circ}C$, respectively, the catalytic activity increased and thermal effect were negligible. $HNO_3$ aqueous solution priming resulted in slight decrease of the catalytic activity, with little effects on $HNO_3$ concentrations. The activity of a spent Pd-based catalyst with respect to VOC molecule was observed to follow sequence: xylene> toluene> benzene. Benzene. toluene and xylene could be removed to almost 100% by a spent Pd-based catalyst primed with hydrogen.

• Journal of Environmental Science International
• /
• v.16 no.4
• /
• pp.433-440
• /
• 2007

The photodegradation and by-products of the gaseous toluene with $TiO_2$ (P25) and short-wavelength UV ($UV_{254+185nm}$) radiation were studied. The toluene was decomposed and mineralized efficiently owed to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the $TiO_2$ surface. The toluene by the $UV_{254+185nm}$ photoirradiated $TiO_2$ were mainly mineralized $CO_2$ and CO, but some water-soluble organic intermediates were also formed under severe reaction conditions. The ozone and secondary organic aerosol were produced as undesirable by-products. It was found that wet scrubber was useful as post-treatment to remove water-soluble organic intermediates. Excess ozone could be easily removed by means of a $MnO_2$ ozone-decomposition catalyst. It was also observed that the $MnO_2$ catalyst could decompose organic compounds by using oxygen reactive species formed in process of ozone decomposition.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.1
• /
• pp.111-116
• /
• 2014

The kinetics and mechanism of oxidation of sulfanilic acid by N-chloro-p-toluene sulfonamide (chloramine-T) have been studied in acid medium. The species of chloramine-T were analysed on the basis of experimental observations and predominantly reactive species was taken into account for proposition of most plausible reaction mechanism. The derived rate law (1) conforms to such a mechanism. $$-\frac{d[CAT]}{dt}=\frac{kK_1[RNHCl][SA]}{K_1+[H^+]}$$ (1) All kinetic parameters were evaluated. Activation parameters such as energy and entropy of activation were calculated to be $(61.67{\pm}0.47)kJmol^{-1}$ and $(-62.71{\pm}2.48)kJmol^{-1}$ respectively employing Eyring equation.

• Korean Chemical Engineering Research
• /
• v.44 no.2
• /
• pp.193-199
• /
• 2006

The catalytic oxidation of toluene over $-Al_2O_3$ supported copper-manganese oxide catalysts in the temperature range of $160-280^{\circ}C$ was investigated by employing a fixed bed flow reactor. The catalysts were characterized by BET, scanning electron microscopy (SEM), temperature-programmed reduction(TPR), temperature-programmed oxidation(TPO), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction(XRD) techniques. Catalytic oxidation of toluene was achieved at the below $280^{\circ}C$, and the optimal content of copper and manganese in the catalyst was found to be 15.0 wt％Cu-10.0 wt％Mn. From the TPR/TPO and XPS results, the redox peak of 15 Cu-10 Mn catalyst shifted to the lower temperature, and the binding energy was shifted to the higher binding energy. Furthermore, It is considered that $Cu_{1.5}Mn_{1.5}O_4$ is superior to Mn oxides and CuO in the role as active factor of catalysts from the XRD results and also catalytic activities are dependent on the redox ability and high oxidation state of catalysts.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.651-656
• /
• 2005

Toluene, which is emitted from textile process, is considered as an important hazardous air pollutant. In this study, the catalytic activity of transition metal oxides(Cu, Mn, V, Cr, Co, Ni, Ce, Sn, Fe, Sr, Cs, Mo, La, W, Zn)/${\gamma}-Al_2O_3$ catalysts was investigated to carry out the complete oxidation of toluene. The metal catalysts were characterized by XRD-ray diffraction), FE-SEM(Field Emission Scanning Electron Micrograph), BET(Brunauer Emmett Teller) method and TPR(Temperature Programmed Reduction). Among the catalysts, Cu/${\gamma}-Al_2O_3$ was highly promising catalyst for the oxidation of toluene. From the BET results, it seems that the catalytic activity is not correlated to the specific surface area. XRD results indicated that most of catalysts exist as amorphous phase. From the FE-SEM results, it was observed that copper on ${\gamma}-Al_2O_3$ surface was well dispersed among catalysts. The catalytic activity for the toluene oxidation could be explained with that metal oxide catalyst was dispersed well over supports and was attributed to reduction activity in surface of catalysts.