18 results on '"Pen-Yuan Chen"'
Search Results
2. Covalent organic polymer derived carbon nanocapsule–supported cobalt as a catalyst for activating monopersulfate to degrade salicylic acid
- Author
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Eilhann E. Kwon, Shaoping Tong, Kun-Yi Andrew Lin, Fang-Chih Chang, Duong Dinh Tuan, Siming You, and Pen-Yuan Chen
- Subjects
inorganic chemicals ,Carbonization ,Process Chemistry and Technology ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Nanocapsules ,Catalysis ,chemistry ,Chemical engineering ,Covalent bond ,Reagent ,Chemical Engineering (miscellaneous) ,0210 nano-technology ,Waste Management and Disposal ,Cobalt ,Carbon ,0105 earth and related environmental sciences - Abstract
As salicylic acid (SAC) is an extensively used pharmaceutical, discharge of SAC into the environment has caused serious threats to ecology in view of its toxicity. Therefore, SO4•−-involved chemical oxidation methods have been employed for eliminating SAC. Since monopersulfate (MPS) has become a popular reagent for producing SO4•−, an alternative heterogeneous Co-based catalyst is proposed by using a Co-coordinated covalent organic polymers (Co-COP) as a precursor. Via carbonization, Co-COP is transferred by conversion of Co ions to Co/CoO nanoparticle and conversion of COP to N-doped carbon nanocapsules (CNC), respectively, to form a unique composite of Co NPs embedded into carbon nanocapsule (CoCNC). CoCNC exhibits a higher catalytic activity than Co3O4 nanoparticle for activating MPS to degrade SAC because of synergistic effects between Co NPs and the N-doped CNC which not only acts as the support but also provides active sites. Hence, CoCNC+MPS could afford a much lower Ea value (25.4 kJ/mol) of SAC degradation than the reported values. Moreover, CoCNC is still efficient for removing SAC even in the presence of high-concentration NaCl and SDS. CoCNC can be also recyclable over many cycles and maintain its catalytic activities, confirming that CoCNC is an advantageous catalyst for MPS activation.
- Published
- 2021
3. A case study on the application of the derivation calculation formula and fuzzy similarity on the test project of Regional Competition, National Taiwan Skills Competition in the trade of joinery
- Author
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Hao-Chang Tsai, Pen-Yuan Chen, Chien-Nan Chen, Huang-Ning Lee, and An-Sheng Lee
- Subjects
010302 applied physics ,Woodworking ,02 engineering and technology ,Competitor analysis ,Type (model theory) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Test (assessment) ,Competition (economics) ,Transformation (function) ,Hardware and Architecture ,Vocational education ,0103 physical sciences ,Econometrics ,Electrical and Electronic Engineering ,Derivation calculation ,0210 nano-technology ,Mathematics - Abstract
This study aimed to analyze the test project of joinery trade in the Regional Competition, Taiwan National Skills Competition (hereinafter referred to as Regional Competition) and to assess the association between test projects of different sessions by the Derivative Calculation Equation ( $$\sum\nolimits_{{i = 36 - 48}}^{{n}} {\rho 49th\chi }$$ ) and fuzzy similarity, which was expected to help to analyze the species, the type and method of joints to be used in the Regional Competition. According to the result, (1) there was no significant variation among the species of materials adopted in the 36th to 48th Regional Competition; (2) “open bevel mortise-tenon joint” was the one with the maximum assessed value in the types of joints; (3) the values of assessment of “open mortise-tenon joint” and its transformation were the maximum in the methods of joints. The overall result of assessment conducted by the Derivation Calculation Equation was reliable and associated with fuzzy similarity, and it was expected to help to improve the strategy of capacity assessment in vocational education and training and to further increase learning efficiency and skill level of the competitors. Under the systematic method, the strategy of training and guidance of assessment can be established to nurture more professional talents in woodworking.
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- 2019
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4. Impacts of holiday characteristics and number of vacation days on 'holiday effect' in Taipei: Implications on ozone control strategies
- Author
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Yu-Shiuan Lin, Chein-Jung Shiu, Charles C.-K. Chou, Pen-Yuan Chen, Wei-Nai Chen, and Pei-Hua Tan
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Pollutant ,Atmospheric Science ,Ozone ,Evening ,010504 meteorology & atmospheric sciences ,Air pollution ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Toxicology ,chemistry.chemical_compound ,chemistry ,Air pollutants ,medicine ,Environmental science ,Air quality index ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
This study investigated the influence of holiday characteristics and numbers of vacation days on the “holiday effect” of three crucial Chinese holidays in Taipei. Surface measurements of NOx, CO, NMHC, O3, SO2, and PM10 from 13 air quality-monitoring stations of the Taiwan Environmental Protection Administration (TEPA) in the Taipei metropolitan area during holiday and non-holiday periods of 1994–2012 were used. All six pollutants were proven to exhibit holiday effects between Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods. However, almost all pollutants exhibited holiday effects for the two other holidays; the exceptions were O3 between Tomb Sweeping Day (TSD) and non-Tomb Sweeping Day (NTSD) periods and CO and PM10 between Mid-Autumn Day (MAD) and non-Mid-Autumn Day (NMAD) periods. Air pollutants, including NOx, CO, NMHC, SO2, and PM10, that exhibited holiday effects had consistently lower concentrations in holiday periods than in non-holiday periods, whereas O3 concentrations were higher in holiday periods than in non-holiday periods. A widespread holiday effect with consistent signs indicates a high degree of urbanization in the study area. Compared with CNY–NCNY and MAD–NMAD periods, the TSD–NTSD period had a considerably lower difference of the titration effect, lower NOx resulting in less ozone destruction, in evening traffic hours and an inconsistent holiday effect in the daytime and nighttime, leading to the lack of O3 holiday effect. Because the MAD period had more nighttime activities than the other two holiday periods did, the MAD–NMAD period lacked CO and PM10 holiday effects. The prevalently higher ratios of CO, NMHC, SO2, and PM10 relative to NOx as a proxy of mobile sources and a lower PM2.5/PM10 ratio in the MAD period than in the CNY and TSD periods indicate different pollution sources oriented from holiday activities. The air pollutants exhibited a weakening trend are all associated with a greater improvement in air quality during the non-holiday periods than the holiday periods, which implies successful air pollution control policies. Holiday effects of NOx, NMHC (p
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- 2019
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5. One-step synthesized 3D-structured MOF foam for efficient and convenient catalytic reduction of nitrogen-containing aromatic compounds
- Author
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Eilhann E. Kwon, Siming You, Jia-Yin Lin, Kun-Yi Andrew Lin, Wen-Da Oh, Thomas Wi-Afedzi, Farshid Ghanbari, Pen-Yuan Chen, and Chao-Wei Huang
- Subjects
Materials science ,Process Chemistry and Technology ,Substrate (chemistry) ,One-Step ,Selective catalytic reduction ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,Electrochemistry ,01 natural sciences ,Catalysis ,Metal ,020401 chemical engineering ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,engineering ,Metal-organic framework ,Noble metal ,0204 chemical engineering ,Safety, Risk, Reliability and Quality ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Biotechnology - Abstract
Metal Organic Frameworks (MOFs) receive increasing attention for 4-nitrophenol (4-NP) reduction; however the existing studies of using MOFs for 4-NP reduction all involve with noble metals. Moreover, the reported MOFs are very fine powders which are inconvenient for realistic implementation. Thus, the present study proposes to develop a MOF foam which exhibits macroscale features of foam and microscale functionalities of MOFs. Specifically, a Cu foam is selected as the macroporous substrate which serves as a porous support and the metal source for synthesizing Cu-based MOF, HKUST-1, via an one-step electrochemical method. The resulting HKUST-1 foam can act as a convenient catalyst for reduction of 4-NP to 4-AP in either batch-type or flow-thru-type reactions. The corresponding activation energy (Ea) of 4-NP reduction (43.3 kJ/mol) is also significantly lower than Ea values of reported catalysts, including noble metal catalysts, whereas the corresponding TOF (48.3 min−1) is higher than many other catalysts. HKUST-1 foam can also efficiently catalyze reduction of methylene blue (MB) to fully decolorize its color. In addition, HKUST-1 foam could be reused over multi-cycles and retain its activity for reduction of 4-NP and MB. These features validate that HKUST-1 foam is a practical, convenient, and reusable catalyst for reduction of 4-NP.
- Published
- 2021
6. A two-dimensional knowledge authorization evaluation method enabling inter-enterprise knowledge sharing
- Author
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Pen-Yuan Chen, Yuh-Min Chen, Tsung-Yi Chen, and Chia-Jou Lin
- Subjects
0209 industrial biotechnology ,Descriptive knowledge ,Knowledge management ,General Computer Science ,business.industry ,Computer science ,General Engineering ,Open Knowledge Base Connectivity ,Knowledge value chain ,02 engineering and technology ,Procedural knowledge ,Knowledge sharing ,Body of knowledge ,Knowledge-based systems ,020901 industrial engineering & automation ,Knowledge extraction ,0202 electrical engineering, electronic engineering, information engineering ,Personal knowledge management ,Ontology ,Domain knowledge ,020201 artificial intelligence & image processing ,Organizational structure ,business - Abstract
The success of virtual enterprises lies in the knowledge sharing efficiently in real-time.This study presented the architecture of a three-layer VE knowledge description method.This study designed the knowledge-sharing policy between activities.A two-dimensional knowledge authorization evaluation approach had been developed. Virtual enterprises (VEs) are designed to be flexible in their response to changes in the market and customer needs. Such flexibility is achieved through business alliances in which resources are integrated and shared in real time and the actions of members are unified. In this paper, a three-layer VE knowledge description architecture is first presented. This architecture represents the organizational structure and fundamental elements of the VE as well as the conceptual and physical knowledge in the VE. A two-dimensional method developed for authorizing interenterprise knowledge sharing is then described. This method can be decomposed into two components: (1) A submethod for evaluating the activities of VEs to determine the range of workers who are authorized to share knowledge with other workers, and (2) a submethod for evaluating the hierarchical relationships among VE roles (VERs), correlations among various types of knowledge, and interactions that occur in VE activities to determine the degree of authorized knowledge sharing. These submethods facilitate efficiently exchanging and sharing knowledge in real time within a framework of secure and reasonable access authorization.
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- 2017
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7. Using Green Water Farm to Improve Ecological Restoration
- Author
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Bing-Yu Wu, Hsiao-ling Lu, Pen-Yuan Chen, Ting-Jie Zhuang, Tsai-Fu Chuang, and Yuan-Hsiou Chang
- Subjects
Geography, Planning and Development ,ved/biology.organism_classification_rank.species ,lcsh:TJ807-830 ,Biodiversity ,lcsh:Renewable energy sources ,Artificial Floating Island ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Green Water Farm ,ecological conservation ,Environmental protection ,Aquatic plant ,Terrestrial plant ,Restoration ecology ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,lcsh:GE1-350 ,Special design ,Renewable Energy, Sustainability and the Environment ,ved/biology ,lcsh:Environmental effects of industries and plants ,Environmental engineering ,04 agricultural and veterinary sciences ,lcsh:TD194-195 ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Environmental science ,Water quality ,Green water - Abstract
Artificial Floating Islands (AFIs) are human-made floating structures capable of supporting aquatic vegetation. Previous studies pointed out that most AFIs use aquatic plants to carry out improvement of water quality and ecological conservation. This study proposed a modified AFI system, named Green Water Farm (GWF), to increase the practical application value of traditional AFIs, and added a special design to create an environment that allows for terrestrial plants (including vegetables and flowers) to grow and to carry out improvement of water quality and ecological conservation. The research site was located at the waterfront of Li-tze Lake in Pitou Township, Taiwan. A GWF was established to evaluate the improvement of water quality and ecological conservation. During one year, water quality and ecological conservation assessments were recorded to investigate the performance of GWF system. The research results showed that GWF could improve water quality and ecological conservation. In addition, the results of this study can provide useful information for more food sources for humans and animals, and increase biodiversity and ecological conservation.
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- 2017
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8. Influence of heterogeneity on unsaturated hydraulic properties: (1) local heterogeneity and scale effect
- Author
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Chu-Hui Chen, Pen-Yuan Chen, Jet-Chau Wen, Cheng-Mau Wu, and Nien-Sheng Hsu
- Subjects
Flume ,Scale (ratio) ,Computer simulation ,Hydraulic conductivity ,Soil water ,Environmental science ,Geotechnical engineering ,Soil science ,Water content ,Finite element method ,Physics::Geophysics ,Water Science and Technology ,Spatial heterogeneity - Abstract
Spatial heterogeneity is ubiquitous in nature, which may significantly affect the soil hydraulic property curves. The models of a closed-form functional relationship of soil hydraulic property curves (e.g. VG model or exponential model) are valid at point or local scale based on a point-scale hydrological process, but how do scale effects of heterogeneity have an influence on the parameters of these models when the models are used in a larger scale process? This paper uses a two-dimensional variably saturated flow and solute transport finite element model (VSAFT2) to simulate variations of pressure and moisture content in the soil flume under a constant head boundary condition. By changing different numerical simulation block sizes, a quantitative evaluation of parameter variations in the VG model, resulting from the scale effects, is presented. Results show that the parameters of soil hydraulic properties are independent of scale in homogeneous media. Parameters of α and n in homogeneous media, which are estimated by using the unsaturated hydraulic conductivity curve (UHC) or the soil water retention curve (WRC), are identical. Variations of local heterogeneities strongly affect the soil hydraulic properties, and the scale affects the results of the parameter estimations when numerical experiments are conducted. Furthermore, the discrepancy of each curve becomes considerable when moisture content becomes closer to a dry situation. Parameters estimated by UHC are totally different from the ones estimated by WRC. Copyright © 2012 John Wiley & Sons, Ltd.
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- 2012
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9. Influence of heterogeneity on unsaturated hydraulic properties (2) - percentage and shape of heterogeneity
- Author
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Pen-Yuan Chen, Chu-Hui Chen, Jet-Chau Wen, Cheng-Mau Wu, and Nien-Sheng Hsu
- Subjects
Pressure head ,Hydraulic conductivity ,Soil water ,Environmental science ,Head (vessel) ,Soil science ,Geotechnical engineering ,Porous medium ,Water content ,Finite element method ,Water Science and Technology ,Spatial heterogeneity - Abstract
In subsurface porous media, the soil water retention curve (WRC) and unsaturated hydraulic conductivity curve (UHC) are two important soil hydraulic property curves. Spatial heterogeneity is ubiquitous in nature, which may significantly affect soil hydraulic property curves. The main theme of this paper is to investigate how spatial heterogeneities, including their arrangements and amounts in soil flumes, affect soil hydraulic property curves. This paper uses a two-dimensional variably saturated flow and solute transport finite element model to simulate variations of pressure and moisture content in soil flumes under a constant head boundary condition. To investigate the behavior of soil hydraulic property curves owing to variations of heterogeneities and their arrangements as well, cases with different proportions of heterogeneities are carried out. A quantitative evaluation of parameter variations in the van Genuchten model (VG model) resulting from heterogeneity is presented. Results show that the soil hydraulic properties are strongly affected by variations of heterogeneities and their arrangements. If the pressure head remains at a specific value, the soil moisture increases when heterogeneities increase in the soil flumes. On the other hand, the unsaturated hydraulic conductivity decreases when heterogeneities increase in the soil flumes under a constant pressure head. Moreover, results reveal that parameters estimated from both WRC and UHC also are affected by shapes of heterogeneity; this indicates that the parameters obtained from the WRC are not suitable for predicting the UHC of different shapes in heterogeneous media. Copyright © 2011 John Wiley & Sons, Ltd.
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- 2012
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10. Associations Between Water Quality Parameters and Planktonic Communities in Three Constructed Wetlands, Taipei
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Pei-Fen Lee, Ta-Ching Chou, Chie-Jen Ko, Pen-Yuan Chen, Chun-Han Ko, and Chia-Ji Teng
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Biochemical oxygen demand ,Abiotic component ,Hydrology ,geography ,Suspended solids ,geography.geographical_feature_category ,Ecology ,Wetland ,Plankton ,Zooplankton ,Phytoplankton ,Environmental Chemistry ,Environmental science ,Water quality ,General Environmental Science - Abstract
We used non-metric multidimensional-scaling analysis (NMDS) to analyze the variation and associations of abiotic and biotic variables among and within three constructed wetlands in metropolitan Taipei. Abiotic variables included NH4-N, biochemical oxygen demand, total phosphorus, suspended solids, dissolved oxygen, water temperature, pH, and electrical conductivity and were sampled monthly from April to October 2007. Biotic variables included zooplankton and phytoplankton communities and were sampled in May and August 2007. We sampled front-compartment, mid-compartment, and effluent portions of each wetland. BOD, NH4-N, TP, DO, SS, and pH differed significantly (p
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- 2011
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11. Bioenergy production potential for aboveground biomass from a subtropical constructed wetland
- Author
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Tzu-Fen Liu, Chun-Han Ko, Fang-Chih Chang, Chia-Ji Teng, Pen-Yuan Chen, Yi-Chung Wang, Yiong-Shing Sheu, and Tzenge-Lien Shih
- Subjects
Typha ,geography ,geography.geographical_feature_category ,biology ,Renewable Energy, Sustainability and the Environment ,Biomass ,Forestry ,Wetland ,Carbon sequestration ,biology.organism_classification ,Macrophyte ,Agronomy ,Bioenergy ,Constructed wetland ,Environmental science ,Waste Management and Disposal ,Agronomy and Crop Science ,Urban runoff - Abstract
Wetland biomass has potentials for bioenergy production and carbon sequestration. Planted with multiple species macrophytes to promote biodiversity, the 3.29 ha constructed wetland has been treated 4000 cubic meter per day (CMD) domestic wastewater and urban runoff. This study investigated the seasonal variations of aboveground biomass of the constructed wetland, from March 2007 to March 2008. The overall aboveground biomass was 16,737 kg and total carbon content 6185 kg at the peak of aboveground accumulation for the system emergent macrophyte at September 2007. Typhoon Korsa flood this constructed wetland at October 2007, however, significant recovery for emergent macrophyte was observed without human intervention. Endemic Ludwigia sp. recovered much faster, compared to previously dominated typha. Self-recovery ability of the macrophyte community after typhoon validated the feasibility of biomass harvesting. Incinerating of 80% biomass harvested of experimental area in a nearby incineration plant could produce 11,846 kWh for one month.
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- 2011
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12. Marchantin A, a cyclic bis(bibenzyl ether), isolated from the liverwort Marchantia emarginata subsp. tosana induces apoptosis in human MCF-7 breast cancer cells
- Author
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Pen Yuan Chen, Chia Wei Lin, Chun Jung Chiu, Chia Li Wu, Li Ling Chi, Chung Yang Huang, Chia Nan Chen, and Wei Jan Huang
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Cancer Research ,Cell growth ,Poly ADP ribose polymerase ,Cell Cycle ,Apoptosis ,Breast Neoplasms ,Free Radical Scavengers ,Biology ,Cell cycle ,Cyclin D1 ,Oncology ,MCF-7 ,Biochemistry ,Ethers, Cyclic ,Cell culture ,Caspases ,Cell Line, Tumor ,Bibenzyls ,Humans ,Female ,Cyclin B1 ,Cell Proliferation - Abstract
Liverwort constituents have been reported to exert a broad spectrum of biological activities. In this study, we used a bioactivity-guided separation of an extract from the liverwort species Marchantia emarginata subsp. tosana to determine its anticancer activity. A high level of the active ingredient was isolated from this liverwort and its chemical structure was identified and characterized by various spectra. It was found to be identical to a well-known compound, marchantin A, a cyclic bisbibenzyl ether. However, no anticancer activities of this compound have previously been reported. We found that marchantin A efficiently induced cell growth inhibition in human MCF-7 breast cancer cells, with an IC(50) of 4.0microg/mL. Fluorescence microscopy and a Western blot analysis indicated that marchantin A actively induced apoptosis of MCF-7 cells. The levels of cleaved caspase-8, cleaved caspase-3, cleaved caspase-9, and cleaved poly (ADP ribose) polymerase (PARP) increased. However, the level of Bid markedly decreased in a dose- and time-dependent manner. We also evaluated the anticancer activities of marchantin A on the regulation of cell cycle regulators such as p21, p27, cyclin B1, and cyclin D1. The p21 and p27 gene expressions increased markedly while cyclin B1 and D1 gene expression decreased markedly by treatment with marchantin A. Many report demonstrated that liverwort was suggested to possess potent antioxidant activity. Our results indicate that marchantin A possesses free radical-scavenging activity (EC(50)=20microg/mL). Taken together, for the first time, the compound marchantin A from liverworts demonstrated to be a potent inducer of apoptosis in MCF-7 cells.
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- 2010
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13. A validated spectrophotometric method for quantification of prenylated flavanones in pacific propolis from Taiwan
- Author
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Vassya Bankova, Pen-Yuan Chen, Chia-Nan Chen, Milena Popova, and Chung-Yang Huang
- Subjects
Validation study ,Chromatography ,Chemistry ,DPPH ,Plant Science ,General Medicine ,Repeatability ,Propolis ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,chemistry.chemical_compound ,Complementary and alternative medicine ,Chemical diversity ,Drug Discovery ,Molecular Medicine ,Food Science - Abstract
Introduction – Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for diff erent propolis types according to the corresponding chemical profi le. So far, this has been done only for European propolis. Objective – To develop a rapid low-cost spectrophotometric procedure for quantifi cation of bioactive prenylated fl avanones in Taiwanese propolis. Methodology – The proposed method quantifi es the total fl avanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major fl avanones of the propolis samples (propolins C, D, F and G) were quantifi ed by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the fi rst time for quantifi cation of prenylated fl avanones. Results – Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573–1.791 mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed signifi cant correlation with the antiradical activity against DPPH. Conclusion – The proposed spectrophotometric procedure is useful for routine analyses of Macaranga-type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacifi c propolis. Copyright © 2009 John Wiley & Sons, Ltd.
- Published
- 2009
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14. Arsenic Removal from Drinking Water during Coagulation
- Author
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Janet G. Hering, Pen-Yuan Chen, Menachem Elimelech, and Jennifer A. Wilkie
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inorganic chemicals ,chemistry.chemical_classification ,Flocculation ,Environmental Engineering ,integumentary system ,Alum ,Inorganic chemistry ,chemistry.chemical_element ,Chloride ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,medicine ,Environmental Chemistry ,Ferric ,Water treatment ,Organic matter ,Sulfate ,Arsenic ,General Environmental Science ,Civil and Structural Engineering ,medicine.drug - Abstract
The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the presence of natural organic matter. The pH range for arsenic(V) removal with alum was more restricted than with ferric chloride. For source waters spiked with 20 μg/L arsenic(V), final dissolved arsenic(V) concentrations in the product water of less than 2 μg/L were achieved with both coagulants at neutral pH. Removal of arsenic(III) from source waters by ferric chloride was both less efficient and more strongly influenced by source water composition than removal of arsenic(V). The presence of sulfate (at pH 4 and 5) and natural organic matter (at pH 4 through 9) adversely affected the efficiency of arsenic(III) removal by ferric chloride. Arsenic(III) could not be removed from source waters by coagulation with alum.
- Published
- 1997
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15. Arsenic removal by ferric chloride
- Author
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Pen-Yuan Chen, Jennifer A. Wilkie, Menachem Elimelech, Sun Liang, and Janet G. Hering
- Subjects
inorganic chemicals ,Inorganic chemistry ,chemistry.chemical_element ,Concentration effect ,General Chemistry ,engineering.material ,Chloride ,Hydrous ferric oxides ,Adsorption ,chemistry ,engineering ,medicine ,Coagulation (water treatment) ,Ferric ,Water treatment ,Arsenic ,Water Science and Technology ,medicine.drug - Abstract
Bench-scale studies were conducted in model freshwater systems to investigate how various parameters affected arsenic removal during coagulation with ferric chloride and arsenic adsorption onto preformed hydrous ferric oxide. Parameters included arsenic oxidation state and initial concentration, coagulant dosage or adsorbent concentration, pH, and the presence of co-occurring inorganic solutes. Comparison of coagulation and adsorption experiments and of experimental results with predictions based on surface complexation modeling demonstrated that adsorption is an important (though not the sole) mechanism governing arsenic removal during coagulation. Under comparable conditions, better removal was observed with arsenic(V) [As(V)] than with arsenic(III) [As(III)] in both coagulation and adsorption experiments. Below neutral pH values, As(III) removal-adsorption was significantly decreased in the presence of sulfate, whereas only a slight decrease in As(V) removal-adsorption was observed. At high pH, removal-adsorption of As(V) was increased in the presence of calcium. Removal of As(V) during coagulation with ferric chloride is both more efficient and less sensitive than that of As(III) to variations in source water composition.
- Published
- 1996
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16. Impact of flood damage on pollutant removal efficiencies of a subtropical urban constructed wetland
- Author
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Hwey-Lien Hsieh, Tsai-Ming Lee, Fang-Chih Chang, Pen-Yuan Chen, Hsin-Hsiung Chen, Chung-Yu Guan, and Chun-Han Ko
- Subjects
Environmental Engineering ,Nitrogen ,Drainage basin ,Wetland ,Efficiency ,Disasters ,Ammonia ,Environmental Chemistry ,Water Pollutants ,Cities ,Waste Management and Disposal ,Environmental Restoration and Remediation ,Pollutant ,Hydrology ,geography ,Tropical Climate ,geography.geographical_feature_category ,Cyclonic Storms ,Flooding (psychology) ,Environmental engineering ,Sediment ,Phosphorus ,Pollution ,Floods ,Oxygen ,Typhoon ,Wetlands ,Constructed wetland ,Environmental science ,Water quality - Abstract
Typhoons and hurricanes in subtropical/tropical regions can induce significant environmental changes (e.g., mass flooding and inundations). However, the damage to the pollutant removal efficiencies of constructed wetlands brought about by these natural disturbances has been neglected in major studies conducted in temperate climates. Therefore, this study compares the pollutant removal performance of a constructed wetland in the Danshui River Basin, before and after the system was inundated with flooding from Typhoon Krosa in 2007. The pollutant removal performance of the free water surface (FWS) constructed wetland was investigated monthly from September 2006 to April 2008. Results of the study demonstrated that this FWS wetland effectively removed 64.3% BOD, 98.9% NH(4)-N, and 39.5% Total-P before Typhoon Krosa. However, the extensive flooding caused by Typhoon Krosa swept over most of the aboveground plant community and deposited the sediment onto the bottom of each compartment. Subsequently, reduced pollutant removal efficiencies were observed. Only 37.7% BOD, 35.1% NH(4)-N, and 31.8% Total-P were removed after this event, although the flow regime was immediately restored. Comparing the water quality data for the FWS wetland before and after Typhoon Krosa revealed the immediate, quantitative damage to the pollutant removal performance caused by the typhoon's inundation. Consequently, a high-flow bypass and additional preventive measures would protect any constructed wetland in areas subject to typhoons.
- Published
- 2010
17. A validated spectrophotometric method for quantification of prenylated flavanones in pacific propolis from Taiwan
- Author
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Milena, Popova, Chia-Nan, Chen, Pen-Yuan, Chen, Chung-Yang, Huang, and Vassya, Bankova
- Subjects
Spectrometry, Gamma ,Picrates ,Biphenyl Compounds ,Flavanones ,Euphorbiaceae ,Taiwan ,Reproducibility of Results ,Free Radical Scavengers ,Propolis ,Statistics, Nonparametric ,Phenylhydrazines - Abstract
Because of its chemical diversity, the only way to standardise propolis is to specify multiple standards for different propolis types according to the corresponding chemical profile. So far, this has been done only for European propolis.To develop a rapid low-cost spectrophotometric procedure for quantification of bioactive prenylated flavanones in Taiwanese propolis.The proposed method quantifies the total flavanones on the basis of their absorption as coloured phenylhydrazones formed by interaction with 2,4-dinitrophenylhydrazine. The procedure was validated through model mixture of compounds representing the composition of Taiwanese propolis according to previous studies. The major flavanones of the propolis samples (propolins C, D, F and G) were quantified by HPLC. Antiradical activity against DPPH was also measured. The DNP (dinitrophenylhydrazine) spectrophotometric method is applied for the first time for quantification of prenylated flavanones.Spectophotometric procedure applicable to new type propolis (Macaranga type) was developed with recovery between 105 and 110% at the concentration range of 0.573-1.791 mg/mL. Six propolis samples were analysed by spectrophotometry using the procedure developed and validated, and by HPLC as the results demonstrated satisfactory agreement. Neither the spectrophotometric data nor the values measured by HPLC showed significant correlation with the antiradical activity against DPPH.The proposed spectrophotometric procedure is useful for routine analyses of Macaranga-type propolis, because of its simplicity, repeatability and acceptable accuracy. Its application to a number of commercial samples could be used as a basis for standardisation and quality control of Pacific propolis.
- Published
- 2009
18. Using Green Water Farm to Improve Ecological Restoration.
- Author
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Yuan-Hsiou Chang, Ting-Jie Zhuang, Tsai-Fu Chuang, Bing-Yu Wu, Hsiao-ling Lu, and Pen-Yuan Chen
- Abstract
Artificial Floating Islands (AFIs) are human-made floating structures capable of supporting aquatic vegetation. Previous studies pointed out that most AFIs use aquatic plants to carry out improvement of water quality and ecological conservation. This study proposed a modified AFI system, named GreenWater Farm (GWF), to increase the practical application value of traditional AFIs, and added a special design to create an environment that allows for terrestrial plants (including vegetables and flowers) to grow and to carry out improvement of water quality and ecological conservation. The research site was located at the waterfront of Li-tze Lake in Pitou Township, Taiwan. A GWF was established to evaluate the improvement of water quality and ecological conservation. During one year, water quality and ecological conservation assessments were recorded to investigate the performance of GWF system. The research results showed that GWF could improve water quality and ecological conservation. In addition, the results of this study can provide useful information for more food sources for humans and animals, and increase biodiversity and ecological conservation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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