Papers by Author: Yung Hsu Hsieh

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Authors: Chen Yu Chang, Yu Jie Chang, Yung Hsu Hsieh, Ching Hsing Lin, Shih Hung Yen
Abstract: . The study combined UV/TiO2 with ultrasonic procedure to degrade azo dye wastewater of Acid Yellow 17. The effects of factors including pH value, initial concentration of dye, and quantities of TiO2, Fe (II), and Fe (III) added on the removal efficiency of azo dye Acid Yellow 17 were investigated. Experimental results revealed significant additive effect attributed to the combination of two procedures under 13-watt UV irradiation and 10-watt ultrasound. Analysis of the catalyst properties indicated no evident changes in the appearance of crystal and TiO2 catalyst by UV/TiO2 combined with ultrasonic procedure. However, the specific surface area was increased by approximately 53%. No effective formation of hydrogen peroxide (ND  1 mg/L) proved that the addition of Fe (II) and Fe (III) failed to induce the Fenton-like reaction effectively. Nevertheless, the addition of Fe ions affected significantly the initial adsorption and the degradation rate of the dye. Moreover, the treatment efficiency of Fe (III) was found to be superior to that of Fe (II) under the same concentration.
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Authors: Kai Yuan Cheng, Chen Yu Chang, Yung Hsu Hsieh, Kuo Shan Yao, Ta Chih Cheng, Chun Yang Cheng
Abstract: A microwave/Fe3O4 catalytic system was proposed for treatment of volatile organic carbons (VOCs). This system comprises a household microwave oven modified as the reaction chamber, which was fitted with a vertical, cylindrical quartz reactor comprising a catalytic packed column filled with granular Fe3O4, a microwave catalyst of iron (II, III) oxide. Experimental results showed that the destruction and removal efficiency (DRE) of toluene by microwave alone was close to zero, but with the microwave/Fe3O4 system, the temperature of the catalytic packed column increased rapidly and reached thermal balance within 10-15 min. Analysis of the rear gas after combustion showed that most of the toluene was thermal oxidized into CO2 and H2O. The successful application of the proposed microwave/Fe3O4 system to thermal destruction of toluene promises a new technology for treatment of VOCs.
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Authors: Ming Yi Chang, Wei Fu Wang, Yung Hsu Hsieh, Chen Yu Chang
Abstract: The different molar ratios of La/Ti (0.025, 0.050, 0.075 and 0.100) photocatalytic electrodes use in this study were synthesized by sol-gel method and dip-coating method. The XRD pattern of TiO2/ITO presents only anatase phases, [1] but for La-TiO2/ITO presents both anatase and rutile phases. The SEM image of the La-TiO2/ITO showed particles of regular shapes with smaller size (<10nm) compared to the TiO2/ITO, which presented uniform particles of spherical structure and larger size (20nm).The La-TiO2/ITO photocatalytic electrode with molar ratio 0.050 shows the best ability both on the absorbtion and photocatalytsis. Applied potential 2.0V would effectively increase the photoelectrocatlaytic activity under visible light irradiation.
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Authors: Ching Hsing Lin, Yu Jie Chang, Mei Yin Hwa, Yung Hsu Hsieh, Shi Hong Yeh, Chen Yu Chang
Abstract: In this study, the Taguchi method was used to optimize the preparation of titanium dioxide thin film reactor through modified chemical vapor deposition (CVD) method and then conversion ratio of toluene was evaluated at the optimal condition. The results indicated that optimal condition for preparation of TiO2 thin film reactor was as followings: water bath temperature of 80°C, Ti (OC3H7)4 / H2O ratio of 4, carrier gas flow rate of 1000 mL min-1, catalytic oxidation temperature of 400°C, oxidation time of 8 hrs, calcination temperature of 450°C, spraying speed of 30 rpm and furnace linear motion geared motor speed of 75 cm min-1. The conversion ratio of 56.56 ppmv toluene could be achieved up to 99.8% with the irradiation intensity of 3.76μW cm-2 at the flow rate of 300 mL min-1 after 120 minutes.
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Authors: Ta Chih Cheng, Chen Yu Chang, Kuo Shan Yao, Yung Hsu Hsieh, Ling Ling Hsieh, Pin Syuan Wang
Abstract: In this study, titanium dioxide thin film was prepared using the modified chemical vapor deposition. The parameters employed to control the preparation of the catalyst include the temperature of water bath, the Ti(OC3H7)4/H2O ratio, the flow rate of carrier gas, the oxidation temperature, the oxidation time, the calcination temperature, the rotating speed of furnace, and the speed of geared motor. The orthogonal arrays in the design of experimental method proposed by Taguchi were adopted to conduct the multiple-factor experiment. The conversion rate of salicylic acid in the aqueous or heterogeneous phase photocatalysis experiment was employed to identify the optimal conditions for assembly. The results indicated that a higher conversion ratio of the organic substance could be achieved under catalytic oxidation temperature of 400°C, calcination temperature of 550°C, and spraying speed of 30 rpm and the optimal experimental conditions obtained in this study were irradiation with intensity of 2.9 mW cm-2 on salicylic acid at concentration of 250 mg L-1 by both agitation and aeration processes (dissolved oxygen level = 8.2mg O2 L-1) at pH 5, which could achieve optimal hydroxyl radical yield of 5.1 ×10-17 M.
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Authors: Ming Yi Chang, Chen Yu Chang, Yung Hsu Hsieh, Kuo Shan Yao, Ta Chih Cheng, Chun Ta Ho
Abstract: The use of TiO2 as photocatalyst to degrade the organic compounds is an effective method of oxidation process and has been widely studied in environmental engineering. However, TiO2 absorbed the UV light which is only small part of sunlight reaching earth surface to activate photocatalytic procedure is a major disadvantage. Therefore, studies on the development of new TiO2 that its photocatalytic activity can be activated by visible light which is the major part of sunlight will be valuable for field application. In this study, we evaluate the photocatalytic degrading efficiency of porphyrins/TiO2 complexes on the organic pollutants under irradiation with visible light (λ= 419 nm). The results showed that the photodecomposition efficiency of methylene blue were up to 95% and 90% respectively after using NiTPP/TiO2 and ZnTPP/TiO2 irradiated with visible light for 6 h. These evidences reveal that the system of porphyrin/TiO2 complexes has significantly high efficiency of photocatalytic degradation under visible light irradiation.
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Authors: Wei Fu Wang, Cheng Ling Hu, Ming Yi Chang, Yung Hsu Hsieh
Abstract: La–doped TiO2 thin films were synthesized using TTIP, IPA , Acetic acid ,and La2¬O3 as precursors by sol-gel method and dip-coating method. The different molar raitos of La/Ti ( 0.025,0.050,0.075 and 0.100 ) were supported on ITO glass to product photocatalytic electrodes. The properties of both TiO2/ITO and La- TiO2/ITO photocatalytic electrodes were characterized by FE-SEM,BET and XRD. The FE-SEM and BET analytical results demonstrate that La-TiO2/ITO particles have uniform shape and small size (<10nm ) compared with TiO2/ITO. Anotherway, the XRD resultes show that when more molar raitos of La/Ti the crystallites become more percent to of rutile. The La-TiO2/ITO photocatalytic electrode with molar raito 0.05 shows the best photocatalysis with mineralization rate after four hours reaction. On this condition, different Acid Yellow 17 initial concentration and UV light intensity have been research. Applied potential 2.0V would effectively increase the decolonization rate under visible light irradiation.
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Authors: Kuo Shan Yao, Yung Hsu Hsieh, Yu Jie Chang, Ching Hsing Lin, Chen Yu Chang, Ya Chi Chiang
Abstract: The La/TiO2 photocatalyst was prepared by lanthanum into TiO2 structure in a sol-gel process. The catalyst was characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), ESCA, and Brunauer Emmett Teller (BET) analyses. Photocatalytic activities of the supported catalysts were examined through decomposition process of azo-dye Acid Yellow 17 solution under UV irradiation. The results showed that the particle size of TiO2 is about 20 nm, and the particle of La/TiO2 is about 10 nm. The crystal structure is mainly in anatase phase, the contents of the rutile phase increase with the increase of the amount of doped lanthanum. The adsorption capacity of La/TiO2 catalysts increases with lanthanum dosage in the acidic solution. The contribution of actual photodecomposition was determined by desorption process, after the photocatalytic reaction. In the acidic solution, better photodecomposition efficiency is achieved than in the neutral or alkaline solution. The experiments demonstrated that the optimum doping of La at 10 mol %, the maximum photodecomposition in dye concertration at 15 mg L-1 and photocatalytic dosage at 0.75 g L-1, achieving the highest effect.
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Authors: Kuo Shan Yao, Chen Yu Chang, Ta Chih Cheng, Yung Hsu Hsieh, Shi Ren Weng
Abstract: Increasing cycle of water circulation in industrial cooling water system caused accumulation of dissolving materials in circulating water. Subsequently, the problems including scaling, fouling, corrosion and slime occurred. The multiple oxidants including chlorine dioxide, ozone, peroxide hydrogen, and chlorine were prepared using diaphragm electrolysis method to alleviate the problems above in the cooling system. Meanwhile multiple oxidants can also inhibit the accumulation of biological dirt and erosion effectively. The efficiency of multiple oxidants to inhibit precipitation of magnesium carbonate and calcium carbonate can be increased by adjustment of pH value in the whole pipeline system to reduce corrosion rate of the pipeline and to achieve energy-water saving goal. The results showed that the high efficiency of chlorine dioxide mixture was an excellent bio-corrosion inhibitor and bio-accumulation bactericide. The residue concentration of mixture oxidants are at the range of 0.05 ~ 0.25 mg ClO2/L that is high enough to restrain the growth of micro-organisms.
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Authors: Ta Chih Cheng, Kuo Shan Yao, Yung Hsu Hsieh, Ming Yi Chang, Chen Yu Chang, Guan Hao Wang
Abstract: In this study, the V-doped TiO2 was synthesized by sol-gel method and we evaluate the photocatalytic degrading efficiency of V-TiO2 complexes on azo dye wastewater under irradiation with visible light (λ= 419 nm). The results showed that the Anatase structure and nano size of V-TiO2 complexs were formed and they had better photo-response to visible light than pure TiO2. The efficiency of decoloriztion or destruction efficiency was less than 6 % using TiO2 alone but efficiency of 0.10VT-I was up to 90% after irradiated with visible light for 240 min. These evidences also reveal that the system of V-TiO2 complexes can directly utilize the sunlight and can be used to treat organic pollutants in the practical wastewate treatment factories.
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