Browsing by Author "Juang, Yaju"

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A hybrid electrochemical advanced oxidation/microfiltration system using BDD/Ti anode for acid yellow 36 dye wastewater treatment
(2013-12-13)
Juang, Yaju
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Nurhayati, Ervin
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Huang, Chihpin
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Pan, Jill R.
;
Huang, Shihming
Conductive diamond is an excellent electrode material due to its resistance to corrosion, wide potential window, and mechanical stability. Diamond doped with boron (BDD) as the anode in electrooxidation (EO) reactor to degrade trace but refractory pollutants from wastewater has received enormous attention recently. In this study, an innovative BDD/Ti electrooxidation-microfiltration (EO/MF) hybrid system was designed and tested for simultaneous removal of refractory organics and particles in dye wastewater. The system was fabricated in a tubular fashion with BDD/Ti as the anode, stainless steel (SS) as the cathode, and a ceramic membrane in between for filtration practice. The synthetic dye wastewater contained acid yellow 36 (AY-36) as the model organic pollutant while kaolin was added to make up the particles in the suspension. The experiments were operated in a continuous up-flow mode at pH 3 with a current density of 30 mA/cm(2). A complete COD removal and more than 90% removals of color and turbidity from the dye wastewater were achieved, suggesting that particles can be removed via MF would not hinder the performance of EO. In conclusion, the single stage hybrid system of BDD/Ti-EO/MF can be a potent treatment process for dye wastewater. (C) 2013 Elsevier B.V. All rights reserved.
Anodic fabrication of advanced titania nanotubes photocatalysts for photoelectrocatalysis decolorization of Orange G dye
(2016-02-01)
Juang, Yaju
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Liu, Yijin
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Nurhayati, Ervin
;
Nguyen Thi Thuy
;
Huang, Chihpin
Titania nanotubes (TNTs) were fabricated on Ti mesh substrates by the anodizing technique. The effects of preparation variables, such as anodizing voltage, time and calcination temperature on the textural characteristics and photocatalytic activity of TNTs were investigated. The surface morphology, crystalline phase, and chemical composition were analyzed using field emission-scanning electron microscopy and X-ray diffraction. The photo-electrochemical properties of TNTs were examined by voltammetry. The TNTs were tested as a photoanode for advanced oxidation processes, such as photocatalytic, electrocatalytic, and photoelectrocatalytic decolorization of Orange G dye. The well-arranged TNTs electrode prepared in this work showed a high photocurrent density of 101 mu A cm(-2) at an optimum length-to-diameter aspect ratio of 31.2. In dye decolorization tests, the electrochemical photocatalytic system using TNTs as the photoanode achieved total decolorization and 64% mineralization under extended reaction time. These results show that TNTs prepared by this method is greatly stable in prolonged use and suitable as a photoanode in the photocatalytic/photoelectrocatalytic treatments of dye wastewater. (C) 2015 Elsevier Ltd. All rights reserved.
Effects of dynamic polarization on boron-doped NCD properties and on its performance for electrochemical-analysis of Pb (II), Cu (II) and Hg (II) in aqueous solution via direct LSV
(2015-12-17)
Nurhayati, Ervin
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Juang, Yaju
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Rajkumar, Muniyandi
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Huang, Chihpin
;
Hu, Chi-Chang
Boron-doped diamond films electrode has been effectively applied in electroanalysis to detect numerous kinds of electroactive chemicals including heavy metals. The success of this application not only depends on the original quality of the films, but more than that, surface treatment or activation and analytical method applied play important role. Fabricated boron-doped nanocrystalline diamond (BD-NCD) in this work were electrochemically pretreated prior to the measurement of heavy metal ions in the solution. The surface properties of the films were evaluated with FE-SEM, AFM, Raman spectroscopy and XPS. The technique chosen for heavy metal measurement was linear sweep voltammetry (LSV) after comparing with differential pulse and square wave voltammetry. In this study, dynamic polarization applied on the BD-NCD electrode was proven to enhance its surface properties. The result of XPS analysis shows that polarized electrode exhibits diminution of Csp(2) and possess minimum adventitious carbon content on its surface. This leads to an increase of electrode kinetic and promotes its capability for Pb, Cu and Hg ions measurements in the aqueous solution using LSV technique without pre-concentration step. The linearity of current response with increasing heavy metals concentration in an acetate buffer is ranging from 1 to 22.5 mu M for Pb and Cu ions and 1 to 10 mu M for Hg ion. The detection limit and sensitivity are 1.339, 0.102 and 0.666 mu M, and 0.014, 0.104 and 0.057 mu A mu M-1 mm(2) for Pb, Cu and Hg, respectively. The BD-NCD electrode also exhibits capability in simultaneous multi-metals determination although the presence of Cu ion was found to be a disturbance in the system as well. On the other hand, the high content of organics in the real water sample such as lake water also demonstrated to hinder heavy metals measurement. Thus, this study confirms that the BD-NCD after undergoing dynamic polarization are capable of direct determination of Pb, Cu and Hg ions both individually and simultaneously either in the acetate buffer solution or natural water system, within mu M level. (C) 2015 Elsevier B.V. All rights reserved.
Electro-photocatalytic Fenton Decolorization of Orange G Using Mesoporous TiO2/stainless Steel Mesh Photo-Electrode Prepared by the Sol-Gel Dip-Coating Method
(2016-05)
Nurhayati, Ervin
;
Yang, Hsinju
;
Chen, Chienhung
;
Liu, Chingfang
;
Juang, Yaju
A photo-electrochemical process is a powerful and eco-friendly method for treating industrial wastewater. Electro-photocatalytic Fenton (EPF) was employed for orange G decolorization using two kinds of photo-electrodes with TiO2 film-coated stainless steel (SS) mesh. These photo-electrodes are prepared by a dip-coating method from the sol-gel-derived TiO2 sols incorporating with various amounts of P25+TiO2 powders (SGDC method). The single dip-coated electrode with the TiO2 sol containing 50 g/L P25 powders possesses similar crystallinity and decolorization performance to the four repetitive dip-coated electrodes with pure TiO2 sol. The kinetics of orange G decolorization using P25+TiO2 film electrode in photocatalytic (PC), electro-Fenton (EF) and EPF processes followed pseudo first-order kinetics model, and the EPF has the highest reaction rate. The efficiency of orange G decolorization achieves 78% via the EPF reaction for 3 h. The SGDC method using the TiO2 sol containing P25 powders not only enhances the TiO2 coating on the SS substrate, but also produces microcracks in the film, that facilitates the in-situ generation of ferrous ions and further induces the EPF reaction for an effective degradation of organic matter in wastewater.
Electrochemical decolorization of dye wastewater by surface-activated boron-doped nanocrystalline diamond electrode
(2016-07)
Chen, Chienhung
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Nurhayati, Ervin
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Juang, Yaju
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Huang, Chihpin
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環境工程研究所
Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes (EAOPs) to treat it Surface activation of the electrode used in such treatment is an important factor determining the success of the process. The performance of boron-doped nanocrystalline diamond (BD-NCD) film electrode for decolorization of Acid Yellow (AY-36) azo dye with respect to the surface activation by electrochemical polarization was studied. Anodic polarization found to be more suitable as electrode pretreatment compared to cathodic one. After anodic polarization, the originally H-terminated surface of BD-NCD was changed into 0-terminated, making it more hydrophilic. Due to the oxidation of surface functional groups and some portion of sp2 carbon in the BD-NCD film during anodic polarization, the electrode was successfully being activated showing lower background current, wider potential window and considerably less surface activity compared to the non-polailzed one. Consequently, electrooxidation (E0) capability of the anodically-polarized BD-NCD to degrade AY-36 dye was significantly enhanced, capable of nearly total decolorization and chemical oxygen demand (COD) removal even after several times of re-using. The BD-NCD film electrode favored acidic condition for the dye degradation; and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species. (C) 2016 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
Fabrication of alpha-MnO2 nano-particle and nano-rod composite electrodes for capacitive deionization
(2016-08-20)
Chen, Yi-Han
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Juang, Yaju
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Huang, Chihpin
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環境工程研究所
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Institute of Environmental Engineering
Fabrication of boron-doped diamond-like carbon (BDDLC) electrode and its applications for the measurements of Hg2+, Cu2+, and Pb2+ ions in aqueous solutions
(2014-08-10)
Juang, Yaju
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Nurhayati, Ervin
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Huang, Chihpin
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Hu, Chi-Chang
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Rajkumar, Muniyandi
Graphite Supported Stainless-Steel Electrode for the Degradation of Azo Dye Orange G by Fenton Reactions: Effect of Photo-Irradiation
(2019-01-01)
Liu, Ching-Fang
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Huang, C. P.
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Juang, Yaju
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Hu, Chi-Chang
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Huang, Chihpin
An electrode, stainless steel supported on graphite, was used for the degradation of hazardous organic compounds, azo dye Orange G (OG), using the photoelectro- Fenton (PEF) process. Results showed that the applied current controlled the electrogeneration rate of both ferrous ion and hydrogen peroxide, which in turn affected the dye degradation kinetics. At an applied current density of 45Acm-2, the SS-graphite electrode yielded a molar [H2O2]/[Fe2+] ratio of 3.6, which was optimal for dye degradation. Under otherwise identical conditions, UV irradiation significantly enhanced OG degradation, i.e.,PEF is more effective than electro-Fenton (EF) process. At the optimal applied current density of 45Acm-2, or optimal molar [H2O2]/[Fe2+] of 3.6, OG decolorization and total organic carbon removal were 83% (in 3h) and 55% (in 7h), versus 75% (in 3h) and 20% (in 7h) by PEF and EF, respectively. OG degradation by both PEF and EF processes followed the pseudo first-order kinetics, which suggested the major role of OH radical in OG decolorization.
Photoelectrochemical degradation of dye wastewater on TiO2-coated titanium electrode prepared by electrophoretic deposition
(2016-06-13)
Liu, Ching-Fang
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Huang, C. P.
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Hu, Chi-Chang
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Juang, Yaju
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Huang, Chihpin
The degradation of azo dye Orange G (OG) on TiO2/Ti electrode was studied using a photoelectrocatalytic system. TiO2/Ti electrode was prepared by electrophoretic deposition (EPD) process. Results of surface analyses, namely, X-ray diffraction (XRD), SEM, X-ray photoelectron spectroscopy (XPS), and linear sweep voltammetry (LSV), revealed that the optimal EPD condition was a deposition potential of 180 V for 1 min and annealed at 350 degrees C. The TiO2/Ti electrode was used as photoanode and a graphite cathode for the degradation of OG. The coupling effect of photocatalytic and electrochemical oxidation processes was evaluated in terms of the decolorization of OG. The degradation of OG increased in the following increasing order: photocatalysis < electrochemical oxidation < photoelectrochemical degradation. A decolorization of 54.3% was achieved at an applied current density of 75 A cm(-2). The degradation of Orange G follows the first-order kinetics in those three treatment processes, which suggests the participation of OH radicals in the decolorization reaction. (C) 2016 Elsevier B.V. All rights reserved.
Temporal variation and interaction of full size spectrum Alcian blue stainable materials and water quality parameters in a reservoir
(2015-07-01)
Nguyen Thi Thuy
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Lin, Justin Chun-Te
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Juang, Yaju
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Huang, Chihpin
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環境工程研究所
This paper reports on the fate of different fractions of Alcian blue, (AB) stainable material in Pao-Shan reservoir, Taiwan, in a one-year study (2013-2014) and an intensive study during phytoplankton bloom (2014). The interactions between the fractions, including AB stained particles, particle and colloidal transparent exopolymer particles (pTEP and cTEP), dissolved acid polysaccharide (dAPS), and their relationship to other water quality parameters were analyzed. The Flow Cytometer and Microscope (FlowCAM) was for first time used to characterize AB stained particles. The results of the one-year study likely showed relationships of pTEP concentration to phytoplankton count and chlorophyll a, while in the intensive study, AB stained particles abundance and pTEP concentration were correlated neither phytoplankton count nor chlorophyll a, but strongly positively correlated with some phytoplankton species\' abundance. The difference indicates that sampling frequency and phytoplankton composition should be addressed for studying the links between AB stained fractions and phytoplankton. The interaction between different AB stained fractions further suggests that the majority of AB stained particles and pTEP would be directly generated by some phytoplankton species, whereas their abiotic generation by cTEP or dAPS may only have contributed partly to their formation. This differs from previous studies which generally posited that pTEP are mainly formed abiotically from dissolved precursors. Successful application of FlowCAM for visualization of AB stained particles recommends this technique by which particle morphologies can be conserved and morphological features of particle can be simultaneously elucidated. (C) 2015 Elsevier Ltd. All rights reserved.