Browsing by Author "Hsieh, Wen-Pin"

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Characteristic of an innovative TiO(2)/Fe(0) composite for treatment of azo dye
(2007-12-01)
Huang, Chihpin
;
Hsieh, Wen-Pin
;
Pan, Jill Ruhsing
;
Chang, Sue-Min
;
環境工程研究所
The major problem for Fe(0) application is the degradation of performance as time due to the formation of a surface oxide layer and that for TiO(2), is the limit of the efficiency due to the recombination phenomenon. To overcome the problems as well as to improve the performance, our laboratory has been inventing a novel catalyst, which was developed by coating synthesized sol-gel-derived TiO(2) nanoparticles onto the surface of Fe(0). This composite was employed on the degradation of azo dye (Acid Black-24) in the aqueous solution. Results from XPS, XRD and FE-SEM analysis indicated that the laboratory-prepared nanoscale TiO(2)/Fe(0) material is a composite of TiO(2) and Fe(0). The nanoscale TiO(2)/Fe(0) composite with UV irradiation can efficiently decolour and reduce TOC from the simulated wastewater containing Acid Black-24. The efficiency of the TiO(2)/Fe(0) composite with UV irradiation on AB-24 reduction is much more efficient than microscale, and nanoscale Fe(0) and TiO(2) particle (P-25). The evidence shows that TiO(2) particles by sol-gel process were coated on the Fe(0) particles surface, which is attributed to the longer life cycle of Fe(0) reactivity. (c) 2007 Elsevier B.V. All rights reserved.
Characteristic of an innovative TiO2/Fe-0 composite for treatment of azo dye
(2007-12-01)
Huang, Chihpin
;
Hsieh, Wen-Pin
;
Pan, Jill Ruhsing
;
Chang, Sue-Min
;
環境工程研究所
The major problem for Fe-0 application is the degradation of performance as time due to the formation of a surface oxide layer and that for TiO2, is the limit of the efficiency due to the recombination phenomenon. To overcome the problems as well as to improve the performance, our laboratory has been inventing a novel catalyst, which was developed by coating synthesized sol-gel-derived TiO2 nanoparticles onto the surface of Fe-0. This composite was employed on the degradation of azo dye (Acid Black-24) in the aqueous solution. Results from XPS, XRD and FE-SEM analysis indicated that the laboratory-prepared nanoscale TiO2/Fe-0 material is a composite of TiO2 and Fe-0. The nanoscale TiO2/Fe-0 composite with UV irradiation can efficiently decolour and reduce TOC from the simulated wastewater containing Acid Black-24. The efficiency of the TiO2/Fe-0 composite with UV irradiation on AB-24 reduction is much more efficient than microscale, and nanoscale Fe-0 and TiO2 particle (P-25). The evidence shows that TiO2 particles by sol-gel process were coated on the Fe-0 particles surface, which is attributed to the longer life cycle of Fe-0 reactivity. (c) 2007 Elsevier B.V. All rights reserved.
Enhance the photocatalytic activity for the degradation of organic contaminants in water by incorporating TiO(2) with zero-valent iron
(2010-01-01)
Hsieh, Wen-Pin
;
Pan, Jill Ruhsing
;
Huang, Chihping
;
Su, Yu-Chun
;
Juang, Ya-Ju
Titanium dioxide (TiO(2)) has become the most popular photocatalyst in treating persistent organic pollutants. The main disadvantage of TiO(2) is the diminishing photocatalytic activity over time due to the electron-hole pair recombination. Many studies have aimed to prolong the photocatalytic life of TiO(2). Among them, incorporation of zero-valent iron (ZVI) is one of the approaches. In this study, a novel nano TiO(2)/Fe(0) composite (NTFC) was synthesized from a nano neutral TiO(2) sol and a nano zero-valent iron (nZVI), both prepared in our laboratory. The structure, composition and physical property of the NTFC are characterized. The photocatalytic activity of the NTFC was evaluated by the reductive decolourization of an azo dye, Acid Black-24 (AB-24), and was found superior to those of nZVI and nano neutral TiO(2) sol. Evidence suggests that the enhanced activity of NTFC is highly correlated to the ratio of ferrous to ferric ion in the system. The quantities of ferrous and ferric ions in the nZVI and NTFC systems were monitored separately. In the nZVI system, the concentration of ferric ions decreased significantly with time while a high level of ferrous ions was maintained in the NTFC suspension. The ferrous/ferric ratio of the NTFC suspension was substantially increased after irradiation by UV. Evidence from EPR analysis suggests that the excited electrons in the conduction band of the TiO(2) can be trapped by the half reaction of Fe(3+)/Fe(2+). reducing the probability of electron-electron hole pair recombination and sustaining the catalytic life of TiO(2). Corrosion tests further proved that by incorporating TiO(2) with zero-valent iron the surface oxidation of nZVI can be effectively prevented. (C) 2009 Elsevier B.V. All rights reserved.
Enhance the photocatalytic activity for the degradation of organic contaminants in water by incorporating TiO2 with zero-valent iron
(2010-01-01)
Hsieh, Wen-Pin
;
Pan, Jill Ruhsing
;
Huang, Chihping
;
Su, Yu-Chun
;
Juang, Ya-Ju
Titanium dioxide (TiO2) has become the most popular photocatalyst in treating persistent organic pollutants. The main disadvantage of TiO2 is the diminishing photocatalytic activity over time due to the electron-hole pair recombination. Many studies have aimed to prolong the photocatalytic life of TiO2. Among them, incorporation of zero-valent iron (ZVI) is one of the approaches. In this study, a novel nano TiO2/Fe-0 composite (NTFC) was synthesized from a nano neutral TiO2 sol and a nano zero-valent iron (nZVI), both prepared in our laboratory. The structure, composition and physical property of the NTFC are characterized. The photocatalytic activity of the NTFC was evaluated by the reductive decolourization of an azo dye, Acid Black-24 (AB-24), and was found superior to those of nZVI and nano neutral TiO2 sol. Evidence suggests that the enhanced activity of NTFC is highly correlated to the ratio of ferrous to ferric ion in the system. The quantities of ferrous and ferric ions in the nZVI and NTFC systems were monitored separately. In the nZVI system, the concentration of ferric ions decreased significantly with time while a high level of ferrous ions was maintained in the NTFC suspension. The ferrous/ferric ratio of the NTFC suspension was substantially increased after irradiation by UV. Evidence from EPR analysis suggests that the excited electrons in the conduction band of the TiO2 can be trapped by the half reaction of Fe3+/Fe2+. reducing the probability of electron-electron hole pair recombination and sustaining the catalytic life of TiO2. Corrosion tests further proved that by incorporating TiO2 with zero-valent iron the surface oxidation of nZVI can be effectively prevented. (C) 2009 Elsevier B.V. All rights reserved.
Fouling Mitigation by TiO2 Composite Membrane in Membrane Bioreactors
(2012-03-01)
Su, Yu-Chun
;
Huang, Chihpin
;
Pan, Jill Ruhsing
;
Hsieh, Wen-Pin
;
Chu, Min-Chia
Membrane bioreactors (MBRs) have attracted widespread attention in advanced water treatment because of their production of consistent and high-quality effluent. However, membrane fouling during operation has greatly hindered their application. Studies have suggested that a coating of TiO2 nanoparticles on membranes may reduce membrane fouling by enhancing the hydrophilicity of the membrane. In this study, two membranes were coated with TiO2 nanoparticles for membrane fouling mitigation. To evaluate the filtration performance of the TiO2 composite membranes, a synthetic wastewater was prepared to model the municipal wastewater for the MBR operation. The mixed liquor from the MBR was used in the filtration test to evaluate the performance of the TiO2 composite membrane. Filtration tests showed that membrane fouling was reduced substantially, which was attributable to the increased hydrophilicity of the membrane. Results also shows that optimal amount of coating is important in fouling mitigation. An ultrasonic washing test suggests that most of the TiO2 particles were firmly coated on the surface of the composite membrane. DOI: 10.1061/(ASCE)EE.1943-7870.0000419. (C) 2012 American Society of Civil Engineers.
Graphene-Au nanoparticle based vertical heterostructures: A novel route towards high-ZT Thermoelectric devices
(2017-08-01)
Juang, Zhen-Yu
;
Tseng, Chien-Chih
;
Shi, Yumeng
;
Hsieh, Wen-Pin
;
Ryuzaki, Sou
Monolayer graphene exhibits impressive in-plane thermal conductivity (> 1000 W m(-1) K-1). However, the out-of-plane thermal transport is limited due to the weak van der Waals interaction, indicating the possibility of constructing a vertical thermoelectric (TE) device. Here, we propose a cross-plane TE device based on the vertical heterostructures of few-layer graphene and gold nanoparticles (AuNPs) on Si substrates, where the incorporation of AuNPs further inhibits the phonon transport and enhances the electrical conductivity along vertical direction. A measurable Seebeck voltage is produced vertically between top graphene and bottom Si when the device is put on a hot surface and the figure of merit ZT is estimated as 1 at room temperature from the transient Harman method. The polarity of the output voltage is determined by the carrier polarity of the substrate. The device concept is also applicable to a flexible and transparent substrate as demonstrated.
Reductive catalysis of novel TiO2/Fe-0 composite under UV irradiation for nitrate removal from aqueous solution
(2012-01-09)
Pan, Jill Ruhsing
;
Huang, Chihpin
;
Hsieh, Wen-Pin
;
Wu, Bi-Ju
;
環境工程研究所
Groundwater contaminated by nitrate has become a worldwide problem. Existing technologies for nitrate removal, including zero-valent iron reduction, can only transform nitrate ions to predominantly NH4+. As a result, many studies have concentrated on seeking a solution to convert nitrate to N-2. In this study, the efficiencies of nitrate removal from aqueous solution by single (TiO2 and nano zero valent iron, nZVI), and composite (Nano-TiO2-Fe-0 composite, NTFC) system under UV illumination were prepared. Among the three systems, both nZVI and NTFC can effectively remove nitrate. However, only NTFC can achieve satisfactory transformation of nitrate to N-2. Further investigation has proven that the composition of NTFC (TiO2/nZVI ratio) greatly influences the conversion of nitrate to N-2, which can be attributed to the maintenance of high level of ferrous ions in the NTFC system due to its reducing condition. (C) 2011 Elsevier B.V. All rights reserved.