• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.496-498
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• 2011

본 논문에서는 알루미늄 드로스를 재활용하여 생성 된 수산화알루미늄을 이용하여 질소산화물 제거 SCR 촉매를 제조하였다. 현재 상용중인 촉매와 화학적 특성과 질소산화물 제거 효율을 비교하기 위해 동일 타입의 하니컴 형태의 $V_2O_5-WO_3-TiO_2-Al_2O_3$ SCR 촉매를 제조하였으며, XRF와 BET를 사용하여 화학적 특성을 평가 비교하였다. 또한 MR(Micro Reactor)을 이용하여 $350^{\circ}C$와 $450^{\circ}C$에서 질소산화물 제거 평가를 실시하였으며, 평가 결과 80~90%의 제거 효율을 확인하였다.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2943-2948
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• 2009

Copper-dimethylglyoxime complex (CuDMG) modified Copper electrode (Cu/CuDMG) showed a catalytic activity towards cyclohexanol oxidation in NaOH solution. The modified electrode prepared by the dimethylglyoxime anodic deposition on Cu electrode in the solution contained 0.20 M $NH_4Cl\;+\;NH_4OH\;(pH\;9.50)\;and\;1\;{\times}\;10^{-4}$ M dimethylglyoxime. The modified electrode conditioned by potential recycling in a potential range of -900${\sim}$900 mV vs. Ag/AgCl by cyclic voltammetry in alkaline medium (1 M NaOH). The results show that the CuDMG film on the electrode behaves as an efficient catalyst for the electro-oxidation of cyclohexanol in alkaline medium via Cu (III) species formed on the electrode.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1269-1273
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• 1997

The system which employs iron, palladium, molecular oxygen and hydrogen as a model mono-oxygenase, has been investigated to develop a new method for selective cyclohexane oxidation uner mild conditions. This system provides much higher yield and selectivity for the formation of cyclohexanol and cyclohexanone compared to that of the existing industrial method. When the catalytic system, FeCl2-Pd/alumina, was employed, the oxidation system required acetone as a solvent to be efficient and acidifying the solvent by a little addition of acetic acid or HCl made the system more efficient. The Pd catalyst was recyclable without a significant deactivation but the recycling of ferrous chloride showed the decrease in the activity. On the other hand, the heterogeneous catalytic system, Pd/Fe2O3 could be recovered easily and reused after drying treatment.

• Journal of Adhesion and Interface
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• v.22 no.1
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• pp.1-7
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• 2021

The importance of high capacity energy storage devices has recently emerged for stable power supply through renewable energy generation. From this point of view, the Na-air battery (NAB), which is a next-generation secondary battery, is receiving huge attention because it can realize a high capacity through abundant and inexpensive raw materials. In this study, activated carbon-based catalysts for hybrid type Na-air batteries were prepared and their characteristics were compared and analysed. In particular, from the viewpoint of resource recycling, activated carbon (Orange-C) was prepared using discarded orange peel, and performance was compared with Vulcan carbon, which is widely used. In addition, a Pt/C catalyst (homemade-Pt/C, HM-Pt/C) was synthesized using a modified polyol method to check whether the prepared activated carbon can be used as a supported catalyst, and a commercial Pt/C catalyst (Commercial Pt/C) and electrochemical performance were compared. The prepared Orange-C exhibited a typical H3 type BET isotherm, which is evidence that micropore and mesopore exist. In addition, in the case of HM-Pt/C, it was confirmed through TEM analysis that Pt particles were evenly distributed on the activated carbon supported catalyst. In particular, the HM-Pt/C-based NAB showed the smallest voltage gap (0.224V) and good voltage efficiency (92.34%) in the 1st galvanostatic charge-discharge test. In addition, the cycle performance test conducted for 20 cycles showed the most stable performance.

• Resources Recycling
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• v.29 no.2
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• pp.55-61
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• 2020

Selective catalytic reduction (SCR) has been a promising technology to reduce the air pollution caused by nitrogen oxides (NOx) in several industries. The consumption of SCR catalysts increases every year as technology evolves, however those have a limited lifespan and usually end up in landfills after they deactivate. Currently, the most widely used catalyst for and stationary applications is V₂O₅-WO₃/TiO₂ which can contain around 50% wt V₂O₅ and 7-10% wt of WO₃. The vast uses for both vanadium and tungsten and the worldwide interest in recycling methods that allow for the extraction of metals from secondary sources represent the major motivation for this research. The extraction time, pH dependency, extraction concentration studies were carried out using Aliquat 336 in exxol D80 as the extractant. It was determined that to optimize the extraction of both metals 30min of contact time with an organic phase containing 0.5mol/L of Aliquat 336 are needed at a slightly acidic pH (~5.0). In addition, counter McCabe-Thiele studies allowed us to determine that one stage is necessary for the removal of 99% of vanadium while 2 stages are necessary for the extraction of tungsten and counter current simulations proved that the theoretical approach was correct.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.3-10
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• 2006

The solvent extraction for the separation of platinum group metals from the leach liquor of spent automotive catalysts has been studied. Tri-n-butyl phosphate (TBP), tri-n-octylamine (TOA) and di-n-hexyl sulfide (DHS) were used as extractants and kerosene as a diluent. The extraction behavior of platinum, palladium and rhodium has been investigated as functions of different kinds of extractants and their concentrations. In addition, the extraction behavior of the major metal impurities such as cerium, lead, iron, magnesium and aluminum has been investigated. Platinum and palladium were extracted with TBP. And platinum, palladium and rhodium were extracted with TOA. Platinum was co-extracted with palladium into the organic phase by solvent extraction using SFI-6 of DHS extractant, but only palladium was selectively extracted with SFI-6R. The selective extraction of palladium with SFI-6R was found better than that with SFI-6, but the kinetics of extraction with SFI-6R was found poor in comparison to SFI-6. The metal impurities extracted simultaneously during the extraction of platinum group metals should be removed in scrubbing and stripping processes. A suitable process has been proposed for the separation of platinum group metals from the leach liquor of spent automotive catalysts. Initially palladium was extracted with SFI-6R, followed by the separation of platinum with TBP or TOA leaving rhodium in the raffinate.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.17-25
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• 2006

Al-MCM-48 was used as a catalyst to decompose high density polyethylene(HDPE). Catalytic activity of Al-MCM-48 was compared with those of Al-MCM-41, Beta, and ZSM-5. Catalytic decomposition rate over Al-MCM-48 was much higher than at of non-catalytic pyrolysis only. Compared to other catalysts, Al-MCM-48 revealed the little higher activation energy value. The progressive deactivation behavior of the catalysts has also studied. ZSM-5 and Al-MCM-48 showed slower deactivation rates than Al-MCM-41 and Beta. Pyrolysis coupled with gas chromatographic separation and flame ionization detection (Py-GC/ FID) was also performed to assess the characteristics of pyrolysis products. ZSM-5 gave a higher fraction of gaseous products ($C_1-C_4$). Al-MCM-41 and Beta produced mainly $C_5-C_{12}$ products. The selectivity to oil product ($C_5-C_{22}$) obtained with Al- MCM-48 is higher an that with the other catalysts employed in this study.

• Resources Recycling
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• v.17 no.5
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• pp.28-36
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• 2008

The effect of attrition scrubbing on the recovery of platinum group metals (PGMs) from automobile catalytic converters has been investigated. Catalytic converters were first crushed into particles less than 2 mm and attrition scrubbed in the range of 60 min, and then they were sieved with several screens. The catalyst layer, $\gamma$-alumina, was dislodged from the surface of the supporting matrix into fine particles less than $45{\mu}m$ by attrition scrubbing. The fraction of fine particles less than $45{\mu}m$ increased as the residence time for attrition scrubbing increased. The composition of the fine fraction obtained at a residence time of 40 min was $CeO_2$ 19.3%, $ZrO_2$ 1.9% and PGMs 419 ppm. In the fine fraction, the recovery of y-alumina increased proportionally to the residence time. Simultaneously, the recovery rates of $CeO_2$, $ZrO_2$ and PGMs increased to 82.9%, 78.7% and 78.9%, respectively. The production of the fine fraction less than $45{\mu}m$ and the recovery of $\gamma$-alumina increased when the solid concentration and initial feed size increased. Therefore, the attrition scrubbing as the comminution and separation process was concerned to be effective for the recovery of catalyst layer from ceramic supporting matrix by physical impact and shearing action between particles in the scrubbing vessel.

• Resources Recycling
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• v.13 no.5
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• pp.28-36
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• 2004

The extraction of platinum group metals such as Pt, Pd and Rh from spent automobile catalyst has been investigated by leaching in HCl solutions using $HNO_3$ or NaOCl as a oxidant. The effect of type and amount of oxidant, reaction time and pulp density on the extraction of platinum group metals was examined. Platinum group metals were recovered by the cementation method using aluminum as a reducing agent. The extraction ratio was higher when NaOCl was used as a oxidant. The optimum leaching conditions were obtained to be: HCl 8 M, the amount of NaOCl 1.4 mole, leaching temperature $90^{\circ}C$, leaching time 180 minutes, pulp density 400g/L. Under the optimum conditions, the extraction of Pt, Pd and Rh were 96.1%, 93.6% and 77.3%, respectively. With the addition of 2.0g of aluminum which corresponds to 28 equivalent the reduction were 98% for Pt. 98.8% for Pd and 65.3% for Rh, respectively.

• Resources Recycling
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• v.26 no.4
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• pp.42-49
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• 2017

As a fundamental study for the separation of vanadium and tungsten from the leaching solution obtained from the soda roasting and water leaching process of spent SCR (Selective Catalytic Reduction) catalyst was carried out. The precipitation behaviors of vanadium and tungsten using the artificial solution (V: $1g{\cdot}L^{-1}$, W: $10g{\cdot}L^{-1}$) was investigated depending on temperature, NaOH concentration and the amount of $CaCl_2$ (aq.) added. V (aq.) was selectively precipitated at lower temperature than 293 K while tungsten also was precipitated at higher temperature. Precipitation rate of V and W was decreased by the increasing concentration of NaOH. On the other hand, excess Ca addition induced the increase of precipitation rate for V and W due to the formation of $Ca(OH)_2$ following the pH decline. The response surface methodology was employed to optimize the selective precipitation. Vanadium of 99.5% and tungsten of 0.0% was precipitated at $0.5mol{\cdot}L^{-1}$ of aqueous NaOH and 1 equivalent ratio of $CaCl_2$ at 293 K.