Browsing by Author "Pan, Jill Ruhsing"

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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.
Characteristics of soluble microbial products in membrane bioreactor and its effect on membrane fouling
(2010-01-15)
Pan, Jill Ruhsing
;
Su, Yuchun
;
Huang, Chihpin
;
環境工程研究所
;
生物科技學系
In this study, the accumulation and characteristics of soluble microbial products (SMP) in the mixed liquor and the effluent of the membrane bioreactor (MBR) were measured and compared. It was found that the concentration of SMP decreased when the SRT was increased from 10 days to 30 days, and then stabilized as SRT was increased to 60 days. The molecular weight (MW) distributions of SMP indicated that the SMP of larger MW (> 30 kDa) was the most abundant fraction in the MBR. The similar MW distributions of SMP in the mixed liquor and effluent implied that membrane fouling due to SMP in the initial slow fouling stage was not due to size sieving. After the MBR was operated for a period of time, only the SMP of relatively large MW (> 30 kDa) was detected in the mixed liquor. The result indicated that size sieving of SMP occurred only after a cake layer was formed on the membrane surface although the effect was not significant and only worked on larger molecules. The accumulation of hydrophilic components of SMP in the mixed liquor of the bioreactor suggested that the hydrophilic fraction (in carbohydrates) could be the major cause for membrane fouling. (C) 2009 Elsevier B.V. All rights reserved.
Comparison of membrane foulants occurred under different sub-critical flux conditions in a membrane bioreactor (MBR)
(2014-08-01)
Tran-Ngoc-Phu Nguyen
;
Su, Yu-Chun
;
Pan, Jill Ruhsing
;
Huang, Chihpin
;
環境工程研究所
Membrane fouling precludes the widespread application of membrane filtration system from treating wastewater and drinking water, and occurs even under sub-critical flux operations. Hence the characteristics and behavior of membrane foulants should be thoroughly investigated, so as to find ways to reduce membrane fouling in membrane bioreactors. The purpose of this study is to compare the membrane fouling potential at different sub-critical flux operations and for different hydrophobic/hydrophilic membranes, and to investigate the vertical distribution of membrane foulants in a cake layer. Results showed that higher fouling propensity which occurred under 80% of critical flux of hydrophilic membrane was associated with the soluble fraction of proteins and polysaccharides, compared with 60% of critical flux. The cell-bound components were dominant under hydrophobic membrane operation. The highest concentration of proteins and polysaccharides was found between 40% and 80% of the depth of the cake layer. (C) 2014 Elsevier Ltd. All rights reserved.
Effect of Al(III) speciation on coagulation of highly turbid water
(2008-05-01)
Lin, Jr-Lin
;
Huang, Chihpin
;
Pan, Jill Ruhsing
;
Wang, Dongsheng
;
環境工程研究所
In Taiwan, the turbidity of raw water for fresh water treatments can sometimes reach as high as 40000 NTU due to intensive rainfall, especially in typhoon seasons. In response, water works often apply large quantities of coagulants such as polyaluminium chloride (PACl). In this study, simulated and natural highly turbid water was coagulated with two PACls, a commercial product (PACl-1) and a laboratory product (PACl-E). The Al species distributions of PACl-1 and PACl-E under various pH conditions were determined, and the corresponding coagulation efficiency was evaluated. The PACl-E has a wider range of operational pH, while the efficiency of PACl-1 peaks at around neutral pH. For simulated water up to 5000 NTU, the PACl-E was superior to PACl-1 at low dosage and in the pH range studied. Similar results were discovered with natural water, except that when the turbidity was extremely high, the coagulation efficiency of PACl-E decreased significantly due to the presence of large amounts of organic matter. The coagulation of PACl-E was closely related to the content of polycationic aluminium (Al-13) while that of PACl-1 was dictated by the amount of Al, The sludge from PACl-E coagulation had better dewaterability when the optimum dosage was applied. The experimental results suggest that for natural water up to 5000 NTU, PACl containing high Al-13 species is recommended for coagulation. In cases when the water contains high organic matter, efficient coagulation depends upon enmeshment by amorphous aluminium hydroxide. (C) 2008 Elsevier Ltd. All rights reserved.
Effect of sludge characteristics on membrane fouling in membrane bioreactors
(2010-03-01)
Pan, Jill Ruhsing
;
Su, Yu-Chun
;
Huang, Chihpin
;
Lee, Hsin-Chieh
;
環境工程研究所
In this study, the impact of sludge characteristics on membrane fouling in a submerged membrane bioreactor (MBR) was investigated. Bulking sludge due to excess growth of filamentous bacteria was changed to normal sludge by use of an aerobic selector. Excellent effluent quality was achieved in the MBR regardless of the quality of the sludge of the bioreactor. The removal rates of total organic carbon (TOC) and ammonia nitrogen were maintained at around 98 and 99%, respectively, during the entire experiment. However, serious fouling was observed during the occurrence of the bulking sludge despite having larger particle size distribution. Capillary suction time (CST) was found highly related to the amount of soluble microbial products (SMP) and membrane fouling. Therefore, it could be used as a simple indicator for SMP and fouling potential. Filamentous bacteria were found to produce more SMP including soluble polysaccharides and soluble proteins in the mixed liquor, which resulted in severe fouling. In particular, the release of high concentration of soluble polysaccharides resulted in serious fouling in bulking sludge. Bound EPS which was found similar in the normal sludge and bulking sludge was not the main cause for membrane fouling. In conclusion, solutes in mixed liquor such as SMP are responsible for membrane fouling, which cannot be prevented by increasing shear stress. (C) 2009 Elsevier B.V. All rights reserved.
Electrochemical photocatalytic degradation of dye solution with a TiO2-coated stainless steel electrode prepared by electrophoretic deposition
(2013-08-01)
Lin, Wei-Chieh
;
Chen, Chien-Hung
;
Tang, Han-Yu
;
Hsiao, Yu-Cheng
;
Pan, Jill Ruhsing
This study demonstrates a new model for the treatment of azo dye wastewater by means of a heterogeneous photocatalytic degradation coupled with the homogeneous electrochemical Fenton reaction, and is called electrochemical photocatalytic (ECPC) degradation. Titanium dioxide-coated stainless steel (P25-TiO2/SS) mesh was employed as a photo-anode, covered with a uniform layer of P-25-TiO2 using electrophoretic deposition (EPD) in a 2-propanol suspension with 10(-4) M Zn(NO3)(2), at a deposition time of 1 min. After annealing in air at 350 degrees C for 1 h, a crack-free, porous P25-TiO2 layer of ca. 2.14 mu m was obtained. Potential bias was used to enhance the photocatalytic degradation of P25-TiO2/SS towards the target pollutant, azo dye orange G, in an undivided cell under ultraviolet light irradiation. Heterogeneous photocatalytic degradation and a homogeneous electro-Fenton reaction occurred in the system simultaneously when H2O2 and Fe2+ were electrochemically generated on the graphite cathode and photo-anode, respectively, under a suitable potential bias, enhancing the de-colorization and removal of total organic carbon. (C) 2013 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.
Impact of sludge retention time on sludge characteristics and microbial community in MBR
(2011)
Su, Yuchun
;
Pan, Jill Ruhsing
;
Huang, Chihpin
;
Chang, Chialing
;
環境工程研究所
In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.
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.