Browsing by Author "Bai, Hsunling"

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A comparative investigation on the low-temperature catalytic oxidation of acetone over porous aluminosilicate-supported cerium oxides
(2015-03-15)
Lin, Liang-Yi
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Wang, ChenYeh
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Bai, Hsunling
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環境工程研究所
;
Institute of Environmental Engineering
The performance of cerium oxide supported on mesoporous aluminosilicate particles (Al-MSPs) with a nominal Ce and Al loading of 2.8 and 1.2 wt.%, respectively, was evaluated for the low-temperature oxidation of acetone. The influence of the preparation methods, including one-step aerosol-assisted self-assembly (AASA) method and post-synthetic wet impregnation method, was examined. The results showed that the surface area and pore diameter of Ce/Al-MSPs(50/25) prepared by AASA method were similar to those of Ce-Al-MSPs made via traditional impregnation method, while a better metallic dispersion of Ce and Al oxide species on Ce/Al-MSP5(50/25) was observed as compared to that of Ce-Al-MSPs. The catalytic performances of Ce/Al-MSPs(50/25) and Ce-Al-MSPs were compared with that of cerium-impregnated H-ZSM-5 (Ce-ZSM-5) zeolite catalyst. The activity of freshly made catalysts followed the order: Ce/Al-MSPs(50/25) > Ce-ZSM-5 > Ce-Al-MSPs. The superior catalytic behavior of the Ce/Al-MSPs(50/25) could be due to the combined effect of strong surface reducibility and high acid property. Although Ce-ZSM-5 and Ce-Al-MSPs presented high activity for acetone removal in the beginning, their activities quickly decreased due to the coking effect. In contrast, Ce/Al-MSP5(50/25) showed a good stability during a 24 h test at the reaction temperature of 150 degrees C. Both surface reducibility and acidity played crucial roles for their high catalytic performance and high stability at low temperatures. (C) 2014 Elsevier B.V. All rights reserved.
Adsorption behaviors of organic vapors using mesoporous silica particles made by evaporation induced self-assembly method
(2008-04-01)
Hung, Chin-Te
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Bai, Hsunling
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環境工程研究所
;
Institute of Environmental Engineering
Spherical mesoporous silica materials with controllable surface area and uniform pore size were synthesized via evaporation induced self-assembly (EISA) method in this study. Both well-ordered and less-ordered mesoporous silica particle (MSP) adsorbents were made via adjusting the surfactant/silica precursor molar ratio. And the relationships between the physical characteristics of MSP adsorbents and the acetone adsorption behaviors were examined for the first time. The results indicated that an increase in the specific surface area results in an increase in the acetone adsorption capacity. But if a further increase in the surface area causes a less structured adsorbent then the acetone adsorption capacity could become less even though the specific surface area is of the highest value of 1337 m(2)/g. ne acetone adsorption capacity of well-ordered MSP adsorbent is more than twice of that of the commercial ZSM-5 zeolite adsorbent due to its relatively higher surface area and uniform pores. The well-ordered structure of MSP also leads to higher acetone adsorption efficiency and a sharper breakthrough curve due to fast pore diffusion. (C) 2008 Elsevier Ltd. All rights reserved.
Adsorption of Carbon Dioxide from Gas Streams via Mesoporous Spherical-Silica Particles
(2010-04-01)
Lu, Chungsying
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Bai, Hsunling
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Su, Fengsheng
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Chen, Wenfa
;
Hwang, Jyh Feng
A relatively new mesoporous silica sorbent for environmental protection applications (i.e., mesoporous spherical-silica particles [MSPs]), was modified by N-[3(trimethoxysilyl)propyl]ethylenediamine (EDA) solution and was tested for its potential in the separation of carbon dioxide (CO(2)) from flue gas. The CO(2) adsorption capacity of MSP and MSP(EDA) increased with temperature from 20 to 60 degrees C but decreased with temperature from 60 to 100 degrees C. The mechanism of CO(2) adsorption on both samples is mainly attributed to physical interaction regardless of temperature change. The MSP(EDA) have good adsorption performance as compared with EDA-modified zeolite or granular activated carbon conducted in this study and many types of silica sorbents reported in the literature. The cyclic CO(2) adsorption showed that spent MSP(EDA) could be effectively regenerated at 120 degrees C for 25 min and CO(2) adsorption capacity of MSP(EDA) was preserved during 16 cycles of adsorption and thermal regeneration. These results suggests that MSP(EDA) are efficient CO(2) sorbents and can be stably used in the prolonged cyclic operation.
Adsorption/Desorption Behaviors of Acetone over Micro-/Mesoporous SBA-16 Silicas Prepared from Rice Husk Agricultural Waste
(2016-09)
Zeng, Wanting
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Bai, Hsunling
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環境工程研究所
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Institute of Environmental Engineering
The preparation of micro-/mesoporous SBA-16 adsorbent by rice husk derived sodium silicate as the silica source and its acetone adsorption/desorption behaviors were reported for the first time. The pore structural properties of waste-derived SBA-16 materials were controlled and optimized by adjusting the surfactant/silica molar ratios from 0.002 to 0.01 for achieving the best acetone adsorption performance. And the relationship between structural properties and acetone adsorption performances of SBA-16 adsorbents was investigated. The resultant waste-derived SBA-16 materials, denoted as RSBA-16, had specific surface areas of 575-1001 m(2) g(-1), pore sizes of 3.3-3.7 nm and pore volumes of 0.41-0.72 cm(3) g(-1). Among the studied adsorbents, RSBA-16(0.004) exhibited the highest saturated acetone adsorption capacity of 179 mg g(-1). It also showed excellent regeneration stability during 20 consecutive cycles. The results indicated that specific surface areas in both micro-and meso-pore ranges were the main factor that determined the superiority of acetone adsorption capacity of RSBA-16(0.004) over other adsorbents such as mesoporous RMCM-41 and micro-/mesoporous RSBA-15. The acetone adsorption experiments at 500-5000 ppmv demonstrated that the adsorption isotherm was well fitted with the Langmuir model, thus the adsorption of acetone on RSBA-16 might be a monolayer physisorption process. The results demonstrated the high adsorption capacity and cyclic stability of waste-derived RSBA-16(0.004) can be considered as a potential adsorbent for VOCs removals.
Aerosol processing of low-cost mesoporous silica spherical particles from photonic industrial waste powder for CO2 capture
(1970-01-01)
Lin, Liang-Yi
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Bai, Hsunling
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環境工程研究所
;
Institute of Environmental Engineering
"A novel mesoporous silica spherical particle, MSP (AS) was facilely prepared using photonic industrial waste powder as the silica source via salt-templated aerosol spray approach. As an alternative to expensive mesoporous silica materials in prior works, the obtained MSP (AS) possesses advantages of simple and rapid synthesis with low manufacturing costs. The characteristics of the MSP (AS) material were investigated by the XRD. N-2 adsorption-desorption measurement, SEM, TEM and TG/DTG analyses. The results clearly demonstrated the presence of mesoporous siliceous material with high specific surface area (585 m(2)/g), mesopore size (9.1 nm) as well as large pore volume (1.24 cm(3)/g). Furthermore, the MSP (AS) is evaluated as the support of adsorbent in terms of CO2 adsorption. It is observed that the amine-functionalized MSP (AS) adsorbent (TEPA-MSP (AS)) which possessed larger pore diameter and pore volume tends to have a higher adsorption capacity of 127 mg CO2/g adsorbent. This is superior to those of TEPA-SBA-15 (117 mg CO2/g adsorbent), TEPA-MCM-41 (112 mg CO2/g adsorbent) and TEPA-NaY (96 mg CO2/g adsorbent) under the same test condition. The results clearly suggest that the MSP (AS) synthesized using photonic industrial solid wastes via salt-templated aerosol route can be a potential and cost-effective adsorbent for CO2 capture. (C) 2012 Elsevier B.V. All rights reserved."
Aerosol processing of mesoporous silica supported bimetallic catalysts for low temperature acetone oxidation
(2011-10-02)
Wang, Chen Yeh
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Bai, Hsunling
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環境工程研究所
;
Institute of Environmental Engineering
One step aerosol EISA (evaporation induced self-assembly) process for synthesizing Ce/metal-MSPs (mesoporous silica spherical particles) catalysts was investigated. The catalysts were then applied to the catalytic oxidation of acetone. The TEM images showed that increasing Ce/Al loading resulted in clearer observation of the metal oxide particles on the MSPs surface, but an excessive metal quantity would destroy the mesoporous structure of the MSPs support. Tests on the monometallic Ce-MSPs and bimetallic Ce/Al-, Ce/Mn- and Ce/Cu-MSPs under temperatures of 150-350 degrees C demonstrated that Ce/Al-MSPs had the best acetone removal at low temperature ranges of less than 200 degrees C, and it could have similar to 80% acetone removal at reaction temperature of 150 degrees C, space velocity of 15,000 h(-1) and acetone inlet concentration of 1000 ppmv. The synergetic effect was observed for bimetallic Ce/Al- MSPs on the acetone removal as compared to the monometallic Ce-MSPs or Al-MSPs catalysts. The Al loading amount, BET specific surface area and the CeO(2) particle size played important roles on the low temperature catalytic oxidation of acetone at 150 degrees C. The acetone removal of both Ce-MSPs(25) (the molar ratio of Si/Ce = 25) and Ce/Al- MSPs(50/50) (the molar ratio of Si/Ce = 50 and Si/Al = 50) exhibited good stability at 250 degrees C but decayed gradually at 150 degrees C after 24 h tests. (C) 2011 Elsevier B.V. All rights reserved.
Aerosol-assisted deposition of Mn-Fe oxide catalyst on TiO2 for superior selective catalytic reduction of NO with NH3 at low temperatures
(2018-06-01)
Lin, Liang-Yi
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Lee, Chung-Yu
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Zhang, You-Ren
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Bai, Hsunling
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環境工程研究所
A series of Me-Fe/TiO2 catalysts was prepared via an aerosol-assisted deposition method, and used for the selective catalytic reduction of NO with NH3 (NH3-SCR) for the first time. Experimental results show that the spray-deposition Mn-Fe/TiO2, denoted Mn-Fe/TiO2(SD), demonstrates high NH3-SCR activity (> 95% conversion) with high N-2 selectivity (> 90%) at temperatures as low as 80-150 degrees C at a space velocity of 50,000 h(-1). Also, the benefits of the spray deposition for preparing Mn-Fe/TiO2 are highlighted by comparison with co precipitation and wet impregnation. This efficient and reliable technique offers attractive opportunities for largescale manufacture of promising materials with superior deNO catalytic performances.
Al-Cu Pattern Wafer Study on Metal Corrosion Due to Chloride Ion Contaminants
(2010-11-01)
Wu, Bi-Jun
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Bai, Hsunling
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Lin, I. -Kai
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Liu, S. S.
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環境工程研究所
Chloride ions (Cl(-)) in the cleanroom environment induce metal corrosion of integrated circuits, and cause wafer scrap events. In this paper, pattern wafers were designed to monitor critical Cl(-) concentration which leads to metal corrosion effects in a simulated airborne molecular contamination (AMC) environment. The simulated Cl(-) contamination environment was established by placing different numbers of preventive maintenance (PM) wipers in wafer pods and monitored simultaneously by ion mobility spectrometer (IMS) and impinger+ion chromatography (IC) instruments. The exposed Al-Cu pattern wafers were analyzed by the KLA surface scanner and the scanning electron microscope/energy dispersive X-ray spectroscopy analyzer. The results indicate that the IMS and the impinger+IC instruments provide consistent HCl monitoring data. Furthermore, they suggest that pattern wafer exposure tests can be an effective method to monitor metal corrosion. The PM wipers are a simple and effective method to establish simulated source of HCl for studying the AMC effect in ppbv levels. The critical HCl concentration where particles could be found on the wafer surface is around 2.0-3.5 ppbv, and the critical HCl concentration that results in metal corrosion defects is around 4.1-6.4 ppbv.
Analysis of Relationship between Inorganic Gases and Fine Particles in Cleanroom Environment
(2010-06-01)
Lin, I-Kai
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Bai, Hsunling
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Wu, Bi-Jun
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環境工程研究所
;
Institute of Environmental Engineering
The concentrations and characteristics of major components in inorganic gases and fine particles were measured at the photo and etch cleanroom areas in a Taiwan semiconductor factory. The results showed that the major inorganic gases, as expressed in terms of volume concentration, were NH(3) and HF at 7-10 and 4-6 ppbv, respectively. The average PM(2.5) mass concentration were 17.52 and 18.23 mu g/m(3) at the photo and etch areas, respectively, with species of Na(+), NH(4)(+), Cl(-) and SO(4)(2-) had the highest concentrations in the PM(2.5) mass. And the inorganic species account for 56% and 62% of the particulate mass, respectively, at the photo and etch areas. Relatively stronger correlations were observed between NH(4)(+) and SO(4)(2-) with the correlation coefficient R(2) of 0.62 and 0.82, respectively, at the photo and etch areas; this indicates their common source was possibly from the gas to particle formation process. And NH(3) was found to co-exist with HF at the etch area due to their common source as process chemicals (NH(4)OH and HF) in the wet bench. In the predominant NH(3)-rich environment, ammonia is the basic neutralizing agent to form the ammonium aerosol in a cleanroom.
Application of physical vapor deposition process to modify activated carbon fibers for ozone reduction
(2008-05-01)
Lin, Yu-Chih
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Chang, Chung-Liang
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Lin, Tser-Sheng
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Bai, Hsunling
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Yan, Ming-Gu
This study utilized the activated carbon fiber (ACF) modified with metal catalyst via physical vapor deposition (PVD) process (ACF/PVD) to diminish ozone. Furthermore, the ozone removal efficiency of ACF/PVD was compared with that of original ACF and ACF modified with metal catalyst via impregnation process (ACF/impregnation). In addition to the kinds of coated metal and the inlet ozone concentrations, the effects of the coating thickness and the reaction temperature on ACF/PVD for ozone removal were also examined. The results indicate that the ozone removal efficiency of ACF/PVD is better than that of original ACF and ACF/impregnation. The ozone removal efficiency of different metal-coated ACF/PVD in the superior order is gold (Au), and manganese (Mn). The increase of Au-coated thickness (3 nm to 80 nm) on ACF/PVD will enhance the ozone removal. However, when the Mn-coated thickness on ACF/PVD is larger than 15 rim, the ozone removal efficiency displays a declining trend. Furthermore, a higher reaction temperature will result in a better ozone removal of ACF/PVD and the original ACF.
Applying spray pyrolysis to synthesize MnO (x) for decomposing isopropyl alcohol in ozone- and thermal-catalytic oxidation
(2009-07-01)
Chang, Chung-Liang
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Lin, Yu-Chih
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Bai, Hsunling
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Liu, Yu-Huei
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環境工程研究所
Manganese oxides (MnO (x) ) were prepared by spray pyrolysis methods (Mn (S) ) and calcination at 600 and 1,000 A degrees C (Mn(600) and Mn(1000)) in this study. Further, the efficiencies of oxidizing isopropanol (IPA) by these MnO (x) utilizing ozone (OZCO) and thermal catalytic oxidation (TCO) were compared. The results indicated that Mn (S) , which are characterized by larger surface areas, processed gas hourly space velocity of 42,000 h(-1) and inlet IPA concentration of 400 ppm performing IPA decomposition efficiencies approaching 100%, and the reaction temperature was operated at only 85 A degrees C for OZCO. The reaction temperature of TCO operated above 270 A degrees C decomposed IPA at the same efficiency.
Applying Surface Charge Attraction to Synthesizing TiO2/Ag Composition for VOCs Photodegradation
(2013-10-01)
Lin, Yu-Chih
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Bai, Hsunling
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Lin, Chia-Hsin
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Wu, Jin-Fang
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環境工程研究所
This study utilized a unique method to prepare TiO2/Ag composites by operating the pH value of synthesis solution, which causes the opposite charges on the surface between TiO2 and Ag to enhance the combination affinity of TiO2 and Ag due to electron attraction. The results showed that the TiO2/Ag prepared in solution at pH 5.8 was characterized as high TiO2 dispersibility and the optimal combination between TiO2/Ag, due to the opposite surface charges and the greatest difference in zeta potentials between TiO2 and Ag. The prepared TiO2/Ag was utilized to process acetone photodegradation, and the results illustrated that TiO2/Ag prepared in solution at pH 5.8 showed the best performance in photodegrading acetone. With increasing TiO2 coated on Ag in TiO2/Ag, the photodegradation efficiency of acetone was enhanced. In terms of the average efficiency via TiO2 coating amount, 10 wt% was the most optimal efficient proportion of TiO2/Ag for the photodegradation of acetone.
Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst
(2014-05-05)
Van-Huy Nguyen
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Lin, Shawn D.
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Wu, Jeffrey Chi-Sheng
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Bai, Hsunling
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環境工程研究所
The light irradiation parameters, including the wavelength spectrum and intensity of light source, can significantly influence a photocatalytic reaction. This study examines the propylene photo-epoxidation over V-Ti/MCM-41 photocatalyst by using artificial sunlight (Xe lamp with/without an Air Mass 1.5 Global Filter at 1.6/18.5 mW.cm(-2)) and ultraviolet light (Mercury Arc lamp with different filters in the range of 0.1-0.8 mW.cm(-2)). This is the first report of using artificial sunlight to drive the photo-epoxidation of propylene. Over V-Ti/MCM-41 photocatalyst, the propylene oxide (PO) formation rate is 193.0 and 112.1 mu mol.gcat(-1).h(-1) with a PO selectivity of 35.0 and 53.7% under UV light and artificial sunlight, respectively. A normalized light utilization (NLU) index is defined and found to correlate well with the rate of both PO formation and C3H6 consumption in log-log scale. The light utilization with a mercury arc lamp is better than with a xenon lamp. The selectivity to PO remains practically unchanged with respect to NLU, suggesting that the photo-epoxidation occurs through the same mechanism under the conditions tested in this study.
Bifunctional mesoporous Cu-Al-MCM-41 materials for the simultaneous catalytic abatement of NO(x) and VOCs
(2009-01-01)
Karthik, Mani
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Lin, Liang-Yi
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Bai, Hsunling
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環境工程研究所
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Institute of Environmental Engineering
This study explored the possibility of using waste organic solvent as the source of volatile organic compound (VOC) and it served as a reducing agent of selective catalytic reduction (SCR) deNO(x) process, in which the VOC itself can be catalytically oxidized on the mesoporous Cu and/or Al substituted MCM-41 catalysts. The synthesized Cu-Al-MCM-41 catalysts were extensively characterized by powder low-angle X-ray diffraction (XRD), N(2) adsorption-desorption measurements, transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS), (27)Al magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR), electron paramagnetic resonance spectroscopy (EPR) and inductively coupled plasma-mass spectrometer (ICP-MS) analysis. The XRD, TEM and N2 adsorption-desorption studies clearly demonstrated the presence of a well ordered long range hexagonal array with uniform mesostructures. The Cu-Al-MCM-41 materials showed a better long-term-stability than that of copper ion-exchanged H-ZSM-5 (Cu-ZSM-5) zeolite. The Cu-Al-MCM-41 material was found to be an efficient catalyst than that of Cu-MCM-41 without aluminum for the simultaneous catalytic abatement of NO(x) and VOCs, which was attributed to the presence of well dispersed and isolated Cu(2+) ions on the Cu-Al-MCM-41 catalyst as observed by UV-Vis DRS and EPR spectroscopic studies. And the presence of aluminum (Al(3+) ions) within the framework of Cu-Al-MCM-41 stabilized the isolated Cu(2+) ions thus it led to higher and stabilized activity in terms of NO(x) reduction. (C) 2008 Elsevier Inc. All rights reserved.
Bifunctional mesoporous Cu-Al-MCM-41 materials for the simultaneous catalytic abatement of NOx and VOCs
(2009-01-01)
Karthik, Mani
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Lin, Liang-Yi
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Bai, Hsunling
;
環境工程研究所
;
Institute of Environmental Engineering
This study explored the possibility of using waste organic solvent as the source of volatile organic compound (VOC) and it served as a reducing agent of selective catalytic reduction (SCR) deNO(x) process, in which the VOC itself can be catalytically oxidized on the mesoporous Cu and/or Al substituted MCM-41 catalysts. The synthesized Cu-Al-MCM-41 catalysts were extensively characterized by powder low-angle X-ray diffraction (XRD), N-2 adsorption-desorption measurements, transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS), Al-27 magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR), electron paramagnetic resonance spectroscopy (EPR) and inductively coupled plasma-mass spectrometer (ICP-MS) analysis. The XRD, TEM and N2 adsorption-desorption studies clearly demonstrated the presence of a well ordered long range hexagonal array with uniform mesostructures. The Cu-Al-MCM-41 materials showed a better long-term-stability than that of copper ion-exchanged H-ZSM-5 (Cu-ZSM-5) zeolite. The Cu-Al-MCM-41 material was found to be an efficient catalyst than that of Cu-MCM-41 without aluminum for the simultaneous catalytic abatement of NOx and VOCs, which was attributed to the presence of well dispersed and isolated Cu2+ ions on the Cu-Al-MCM-41 catalyst as observed by UV-Vis DRS and EPR spectroscopic studies. And the presence of aluminum (Al3+ ions) within the framework of Cu-Al-MCM-41 stabilized the isolated Cu2+ ions thus it led to higher and stabilized activity in terms of NOx reduction. (C) 2008 Elsevier Inc. All rights reserved.
Bromocresol Green/Mesoporous Silica Adsorbent for Ammonia Gas Sensing via an Optical Sensing Instrument
(2011-04-01)
Chang, Yu-Chang
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Bai, Hsunling
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Li, Shou-Nan
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Kuo, Chun-Nan
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環境工程研究所
A meso-structured Al-MCM-41 material was impregnated with bromocresol green (BG) dye and then incorporated into a UV-Vis DRA spectroscopic instrument for the online detection of ammonia gas. The absorption response of the Al-MCM-41/BG ammonia sensing material was very sensitive at the optical absorption wavelength of 630 nm. A high linear correlation was achieved for ppmv and sub-ppmv levels of ammonia gas. The response time for the quantitative detection of ammonia gas concentrations ranging from 0.25 to 2.0 ppmv was only a few minutes. The lower detection limit achieved was 0.185 ppmv. The color change process was fully reversible during tens of cycling tests. These features together make this mesoporous Al-MCM-41 material very promising for optical sensing applications.
Byproduct Analysis of SO2 Poisoning on NH3-SCR over MnFe/TiO2 Catalysts at Medium to Low Temperatures
(2019-03-01)
Lee, Tsungyu
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Bai, Hsunling
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環境工程研究所
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Institute of Environmental Engineering
The byproducts of ammonia-selective catalytic reduction (NH3-SCR) process over MnFe/TiO2 catalysts under the conditions of both with and without SO2 poisoning were analyzed. In addition to the NH3-SCR reaction, the NH3 oxidation and the NO oxidation reactions were also evaluated at temperatures of 100-300 degrees C to clarify the reactions occurred during the SCR process. The results indicated that major byproducts for the NH3 oxidation and NO oxidation tests were N2O and NO2, respectively, and their concentrations increased as the reaction temperature increased. For the NH3-SCR test without the presence of SO2, it revealed that N2O was majorly from the NH3-SCR reaction instead of from NH3 oxidation reaction. The byproducts of N2O and NO2 for the NH3-SCR reaction also increased after increasing the reaction temperature, which caused the decreasing of N-2-selectivity and NO consumption. For the NH3-SCR test with SO2 at 150 degrees C, there were two decay stages during SO2 poisoning. The first decay was due to a certain amount of NH3 preferably reacted with SO2 instead of with NO or O-2. Then the catalysts were accumulated with metal sulfates and ammonium salts, which caused the second decay of NO conversion. The effluent N2O increased as poisoning time increased, which was majorly from oxidation of unreacted NH3. On the other hand, for the NH3-SCR test with SO2 at 300 degrees C, the NO conversion was not decreased after increasing the poisoning time, but the N2O byproduct concentration was high. However, the SO2 led to the formation of metal sulfates, which might inhibit NO oxidation reactions and cause the concentration of N2O gradually decreased as well as the N-2-selectivity increased.
Capture of CO(2) from flue gas via multiwalled carbon nanotubes
(2009-04-01)
Su, Fengsheng
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Lu, Chungsying
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Cnen, Wenfa
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Bai, Hsunling
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Hwang, Jyh Feng
Carbon nanotubes (CNTs) were modified by 3-aminopropyl-triethoxysilane (APTS) solution and were tested for its CO(2) adsorption potential at multiple temperatures (20-100 degrees C). The physicochemical properties of CNTs were changed after the modification, which makes CNTs adsorb more CO(2) gases. The adsorption capacities Of CO(2) via CNTs and CNTs(APTS) decreased with temperature indicating the exothermic nature of adsorption process and increased with water content in air at 0-7%. The mechanism of CO(2) adsorption on CNTs and CNTs(APTS) appears mainly attributable to physical force regardless of temperature change, which makes regeneration of spent CNTs at a relatively low temperature become feasible. The CNTs(APTS) have good adsorption performance Of CO(2) at 20 degrees C as compared to many types of modified carbon or silica adsorbents documented in the literature. This suggests that the CNTs(APTS) are promising low-temperature adsorbents for CO(2) capture from flue gas. (C) 2009 Elsevier B.V. All rights reserved.
Capture of CO2 from flue gas via multiwalled carbon nanotubes
(2009-04-01)
Su, Fengsheng
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Lu, Chungsying
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Cnen, Wenfa
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Bai, Hsunling
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Hwang, Jyh Feng
Carbon nanotubes (CNTs) were modified by 3-aminopropyl-triethoxysilane (APTS) solution and were tested for its CO2 adsorption potential at multiple temperatures (20-100 degrees C). The physicochemical properties of CNTs were changed after the modification, which makes CNTs adsorb more CO2 gases. The adsorption capacities Of CO2 via CNTs and CNTs(APTS) decreased with temperature indicating the exothermic nature of adsorption process and increased with water content in air at 0-7%. The mechanism of CO2 adsorption on CNTs and CNTs(APTS) appears mainly attributable to physical force regardless of temperature change, which makes regeneration of spent CNTs at a relatively low temperature become feasible. The CNTs(APTS) have good adsorption performance Of CO2 at 20 degrees C as compared to many types of modified carbon or silica adsorbents documented in the literature. This suggests that the CNTs(APTS) are promising low-temperature adsorbents for CO2 capture from flue gas. (C) 2009 Elsevier B.V. All rights reserved.
Catalytic Incineration of Acetone on Mesoporous Silica Supported Metal Oxides Prepared by One-Step Aerosol Method
(2011-04-06)
Wang, ChenYeh
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Bai, Hsunling
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環境工程研究所
;
Institute of Environmental Engineering
Mesoporous silica supported metal oxide catalysts were synthesized by a one-step fast aerosol process based on an evaporation induced self-assembly (EISA) method. They were then applied to the catalytic incineration of VOCs with acetone as the target species. The synthesized metal-MSPs (mesoporous silica particles) were characterized by N(2) adsorption-desorption measurements, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductively coupled plasma-mass spectrometer (ICP-MS) to understand their physical and chemical properties. Tests on various metals of Ce, Mn, Cu, Fe, and Al supported on MSPs over a temperature range of 150-350 degrees C demonstrated that Ce is the best metal for the catalytic incineration of acetone. The Ce-MSPs(10) has a high Ce loading of 9.76 wt %, but its small specific surface area of 615 m(2)/g, poor pore size distribution, and less-ordered pore structure resulted in a relatively lower acetone removal as compared to the Ce-MSPs(25). The Ce-MSPs (25) catalyst appeared to be the best acetone catalytic incineration performance due to the high specific surface area of 951 m(2)/g with highly ordered pore structure as well as optimal Ce metal content of 3.72 wt % so that CeO(2) particles were well dispersed on the porous surfaces. Near complete acetone destruction via Ce-MSPs(25) catalyst was achieved at a temperature of 250 degrees C, acetone inlet concentration of 1000 ppmv and GHSV of 5000 h(-1). The long-term stability test showed that the acetone destruction efficiency can be kept constant during the 96 h test period.