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journal of Environmental Sciences 2008年第8期20卷 1012-1017页

作者： jo wan-kuen LEE jong-Hyo LIM Ho-Jin JEONG Woo-Sik Department of Environmental Engineering Kyungpook National UniversityDaegu 702-701Korea. School of Food and Life Science Inje University KimhaeKyungsangnarado 621-749Korea

The present study investigated the emissions of naphthalene and other compounds from several different moth repellents(MRs) and one toilet deodorant block(TDB)currently sold in Korea,using a headspace *** emission factors and emission rates of naphthalene were studied using a small-scale environmental ***-type products emitted a higher concentration of the total volatile organic compounds(VOCs)(normalized to the weight of test piece)than ball-type products,which in turn emitted higher con...

关键词： volatile organic compounds(VOCs) chemical composition ball-type gel-type paper-type

LED照射光催化剂用于苯、甲苯、乙苯和二甲苯分解(英文)

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催化学报 2012年第10期33卷 1672-1680页

作者： jo wan-kuen KANG Hyun-Jung Department of Environmental Engineering Kyungpook National University

Studies on the use of gas phase applications of light emitting diodes(LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous *** present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania(N-TiO2) prepared by hydrolysis to decompose gaseous benzene,toluene,ethyl benzene,m-xylene,p-xylene,and *** calcined at different temperatures were characterized by various analytical *** degradation efficiency of benzene was close to zero for all *** the other compounds,a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 ***,the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps(blue and white LEDs).The highest degradation efficiency was observed with the use of a calcination temperature of 350 *** average degradation efficiencies for toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene were 35%,68%,94%,and 93%,*** use of blue-and white-LEDs,high light intensity,and low initial concentrations gave high photocatalytic activities for the photocatalytic units using *** morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination *** results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications,but the activity depends on the operational conditions.

关键词： light emitting diode energy efficiency gas phase degradation photocatalyst characterization calcination temperature

Review on inorganic and polymeric materials-coordinated metal-organic-framework photocatalysts for green hydrogen evolution

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journal of Energy Chemistry 2024年第5期92卷 322-356页

作者： Dong-Eun Lee Mohtaram Danish Umair Alam wan-kuen jo School of Architecture CivilEnvironmental and Energy Engineering Kyungpook National University80 Daehak-roBuk-guDaegu 41566Republic of Korea School of Chemical Engineering Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea

Metal-organic frameworks(MOFs)possess a distinct advantage over conventional heterogeneous photocatalysts because of their carefully defined architecture and particular pores,which facilitate the targeted incorporation of other efficient cocatalysts or semiconductor *** integration of MOFs with other materials has resulted in significant breakthroughs,as the coupled materials improve the performance due to the combined *** unique MOF structures allow them to host foreign materials,which results in harvesting the visible region of the solar spectrum and effectively mitigating charge recombination by promoting charge *** review presents an evaluation of the latest developments in the utilization of surface and/or pore chemistry of MOF-supported heterojunctions for photocatalytic green-hydrogen generation with a basic understanding of the mechanism *** review begins with the basic principles of photocatalysis,the significance of MOFs,their optical properties,the methods used for synthesizing MOFs,and their coordination with other inorganic and polymeric ***,methods to increase photocatalytic H2 evolution using MOF-supported heterojunction have been proposed as standard ***,to address environmental challenges,we highlight the future potential of MOF-supported heterojunctions for use in green-energy *** hope that this review provides guidance to researchers in the development of effective heterojunctions based on MOFs to address challenges in energy applications and catalytic processes.

关键词： Renewable energy Environmental challenge Heterojunction Water splitting Photocatalysis

Influence of overhanging tool length and vibrator material on electromechanical impedance and amplitude prediction in ultrasonic spindle vibrator

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 292-310页

作者： Rendi KURNIAwan Moran XU Min Ki CHOO Shuo CHEN Yein KWAK' Jielin CHEN Saood ALI Hanwei TENG Pil wan HAN Gi Soo KIM Tae jo KO Precision Machining Laboratory Department of Mechanical Engineering Yeungnam UniversityGyeongsansiGyeongbuk-doRepublic of Korea Korea Electrotechnology Research Institute(KERI) ChangwonsiGyeongsangnam-doRepublic of Korea KASWIN Co. LtdChangwon-siGyeongsangnamdoRepublic of Korea

This study presents the development of an ultrasonic transducer with a radius horn for an ultrasonic milling spindle(UMS)*** ultrasonic transducer was intended to have a working frequency of approximately 30 *** different materials were considered in the study:stainless steel(SS 316L)and titanium alloy(Ti-6Al-4V).Titanium alloy gave a higher resonance frequency(33 kHz)than stainless steel(30 kHz)under the same preload compression *** electromechanical impedance simulation was carried out to predict the impedance resonance frequency for both materials,and the effect of the overhanging toolbar was *** to the electromechanical impedance simulation,the overhanging toolbar length affected the resonance frequency,and the error was less than 3%.Harmonic analysis confirmed that the damping ratio helps determine the resonance ***,damping ratios of 0.015-0.020 and 0.005-0.020 were selected for stainless steel and titanium alloy,respectively,with an error of less than 1.5%.Experimental machining was also performed to assess the feasibility of ultrasonic-assisted milling;the result was a lesser cutting force and better surface topography of Al 6061.

关键词： Ultrasonic spindle Ultrasonic vibration assisted-milling(UVAM) 1-degree of freedom(DOF) Frequency Amplitude Milling

Visible-light-activated N-doped CQDs/g-C3N4/Bi2WO6 nanocomposites with different component arrangements for the promoted degradation of hazardous vapors

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journal of Materials Science & Technology 2020年第5期40卷 168-175页

作者： Mi Gyeong Kim wan-kuen jo Department of Environmental Engineering Kyungpook National University 80 University RoadBukguDaegu702-701Republic of Korea

To investigate whether the arrangement of componentsin multi-composite photocatalysts may affect their photocatalytic properties,due to different charge-transfer routes,two ternary-nanocomposite photocatalysts with different component arrangements,comprising N-doped carbon quantum dots(NCQDs),g-C3N4(CN),and Bi2WO6(BWO)(hereafter referred to as NCQDs/CN/BWO),were developed,and the photocatalytic degradation of model hazardous vapors under visible-light illumination was *** I NCQDs/CN/BWO,which was developed by the combination of NCQDs/BWO and CN,exhibited photocatalytic ability superior to that of type II NCQDs/CN/BWO,which was developed by the combination of CN/BWO and NCQDs;the superior photocatalytic ability corresponded to the dual properties of NCQDs:charge mediation and upconversion ***,the photocatalytic ability of NCQDs/CN/BWO was greater than those of the reference catalysts;in addition,this photocatalyst exhibited outstanding photochemical ***,the effects of CN/(BWO+CN)weight ratio of the CN/BWO dual nanocomposites and the NCQDs/(BWO+CN+NCQDs)weight percentage of NCQDs/CN/BWO ternary nanocomposites on the pollutant removal efficiency were *** plausible mechanisms over the two NCQDs/CN/BWO photocatalysts for the degradation of hazardous vapors were *** component arrangement approach proposed herein afforded a technique toward the perceptive development of novel multi-component heterostructures for the photocatalytic degradation of hazardous vapors.

关键词： Component arrangement Charge-transfer route NCQDs dual role Charge mediator Upconversion photoluminescence

Photocatalytic decomposition of mobile-source related pollutants using a continuous-flow reactor

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journal of Environmental Sciences 2010年第3期22卷 460-466页

作者： wan-kuen jo Seung-Ho Shin Department of Environmental Engineering Kyungpook National University

This study evaluated the application of a continuous-flow photocatalytic reactor for the control of two mobile-derived pollutants, methyl-tertiary butyl ether （MTBE） and naphthalene, present at in-vehicle levels. Variables tested for this study included the hydraulic diameter （HD）, stream flow rate （SFR）, relative humidity （RH）, and feeding type （FT）. The fixed parameters included contaminant concentration, ultraviolet light source, and the weight of TiO2. In all experimental conditions the adsorption process reached equilibrium within 30 to 180 min for the target compounds, and the outlet concentrations of the photocatalytic oxidation （PCO） reactor while operating reached a steady state within 60 to 180 min. The degradation of the target compounds was dependent on RH, HD, FT, or SFR. The PCO system exhibited high degradation （up to nearly 100% for certain conditions） and mineralization efficiencies of target compounds, suggesting that this system can effiectively be employed to improve indoor air quality. Moreover, it was confirmed that trichloroethylene at urban-ambient level also could enhance the degradation efficiency of naphthalene when applying the PCO technology inside vehicles.

关键词： in-vehicle level methyl-tertiary butyl ether naphthalene trichloroethylene

One-dimensional titania nanotubes annealed at various temperatures for the photocatalytic degradation of low concentration gaseous pollutants

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Particuology 2015年第2期13卷 86-92页

作者： Ho-Hwan Chun wan-kuen jo Department of Naval Architecture and Ocean Engineering Pusan National University Department of Environmental Engineering Kyungpook National University

In this study, one-dimensional titania nanotubes （TNTs） were synthesized using a combined process of chemical and hydrothermal treatments, and their activities for the photocatalytic reactions of selected gaseous pollutants at sub-ppm levels were determined. Additionally, the properties of the TNTs were examined using selected spectroscopic methods. The annealed TNTs showed higher photocatalytic activities for the four target compounds than did the unannealed TNTs. For all the target compounds except benzene, the effect of the annealing temperature on the degradation efficiency was difficult to determine because all degradation efficiencies were very high. However, for benzene, which decomposed with a low efficiency, the degradation activities of the TNTs increased as the treatment temperature was increased from 250 to 300 ℃, while they decreased slightly when the temperature was increased from 300 to 400 ℃. These findings confirm the presence of an optimal annealing temperature for the synthesis of TNTs. Moreover, the average degradation extents for benzene, toluene, ethylbenzene, and o-xylene decreased from 92%, 96%, 99%, and 98% to 77%, 86%, 92%, and 94%, respectively, as the airstream flow rate increased within the range of 1-4L/min. The average degradation extents decreased from 12%, 75%, 87%, and 88% to 3%, 29%, 46%, and 51%, respectively, as the input concentration increased from 0.4 to 1.9 ppm. Overall, these findings suggest that one-dimensional TNTs can be effectively utilized for the degradation of gaseous pollutants under optimal operational conditions.

关键词： vGaseous pollutant Annealing temperature Degradation efficiency Airstream flow rate

Porous g-C_(3)N_(4)-encapsulated TiO_(2) hollow sphere as a high-performance Z-scheme hybrid for solar-induced photocatalytic abatement of environmentally toxic pharmaceuticals

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journal of Materials Science & Technology 2021年第23期82卷 21-32页

作者： Dong-Eun Lee Satyanarayana Moru wan-kuen jo Surendar Tonda School of Architecture CivilEnvironmental and Energy EngineeringKyungpook National University80 Daehak-roBuk-guDaegu41566Republic of Korea Department of Electrical and Computer Engineering Iowa State UniversityCoover HallOsborn DriveAmesIowa 50011USA Department of Physical Sciences Kakatiya Institute of Technology and ScienceWarangal506015TelanganaIndia

Herein,we rationally constructed a hybrid heterostructure comprising porous g-C_(3)N_(4)(CN)-encapsulated anatase TiO_(2) hollow spheres(TOHS)via a synthesis method that involves hydrothermal and calcination *** fabricated hybrid,termed CN/TOHS,demonstrated extraordinary activity toward the degradation of environmentally toxic pharmaceutical substances(acetaminophen and ciprofloxacin)in aqueous solutions under simulated sunlight irradiation;the activity of CN/TOHS was superior to that attained for individual TOHS and CN *** particular,the CN/TOHS hybrid containing 13.3 wt.%of CN on TOHS displayed the optimum degradation activity among the tested catalysts used in this study,and it also possessed exceptional recyclability and stability during consecutive degradation *** remarkable photocatalytic activity and stability of the hybrid were predominantly ascribed to the large solid interfacial contact between constituents,TOHS and CN,induced by effective hybrid structure,which boosted the interfacial charge transfer and impeded with the direct recombination of photo-induced ***,the results of the liquid chromatography-mass spectrometry analysis corroborated the effective mineralization of model pharmaceutical pollutants in the presence of the CN/TOHS *** simple interfacial engineering strategy presented in this study offers a potential route for the rational design of novel catalysts for application in environmental remediation and solar energy conversion.

关键词： TiO_(2)hollow sphere g-C3N4 Hybrid heterostructure Z-scheme charge transfer Pollutant degradation

2D/2D BiOIO_(3)/g-C_(3)N_(4) S-scheme hybrid heterojunction with face-to-face interfacial contact for effective photocatalytic H_(2) production and norfloxacin degradation

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journal of Materials Science & Technology 2023年第17期148卷 19-30页

作者： Dong-Eun Lee Satyanarayana Moru KasalaPrabhakar Reddy wan-kuen jo Surendar Tonda School of Architecture CivilEnvironmental and Energy EngineeringKyungpook National University80 Daehak-roBuk-guDaegu 41566Republic of Korea School of Advanced Sciences Vellore Institute of Technology-Andhra Pradesh(VIT-AP University)AmaravatiAndhra Pradesh 522237India Department of Chemistry and Biochemistry University of South Carolina631 Sumter StreetColumbiaSC 29208United States

A two-dimensional(2D)/2D hybrid heterojunction with face-to-face interfacial assembly is a desirable dimensionality design with significant potential for various photocatalytic applications due to the large interfacial contact area,which facilitates charge migration and ***,we developed an ef-ficient 2D/2D hybrid heterojunction consisting of BiOIO 3 nanoplates(BIO)and g-C_(3)N_(4) nanosheets(CN)using a simple but effective in situ growth method for photocatalytic aqueous antibiotic degradation and H_(2) *** face-to-face interfacial assembly of the BIO and CN components in the BIO/CN hy-brid heterojunction was verified using electron ***,the BIO/CN hybrid heterojunc-tion outperformed both the BIO and CN counterparts in terms of norfloxacin degradation and H_(2) gen-eration under simulated solar light ***,the photocatalytic performance of the hybrid catalyst remained nearly unchanged throughout five consecutive test *** exceptional performance and stability of the hybrid catalyst are attributable to its extended optical absorption range,large interfa-cial contact area provided by the face-to-face assembly in the 2D/2D hybrid configuration,and enhanced photoexcited charge separation efficiency and redox power of the separated charges,which are supported by an efficient S-scheme charge transfer *** study illuminates the rational construction of novel 2D/2D S-scheme hybrid heterojunction photocatalysts with practical applications in environmental remediation and sustainable energy generation.

关键词： g-C_(3)N_(4) BiOIO_(3) Face-to-face interface 2D/2D heterojunction S-scheme charge transfer Solar energy conversion

2D reduced graphene oxide-titania nanocomposites synthesized under different hydrothermal conditions for treatment of hazardous organic pollutants

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Particuology 2018年第1期16卷 165-173页

作者： Migyeong Kim Won-Hwa Hong Woong Kim Sung Hyuk Park wan-kuen jo Department of Environmental Engineering Kyungpook National University Daegu 702-701 Republic of Korea School of Architecture Kyungpook National University Daegu 702-701 Republic of Korea Department of Materials Science and Metallurgical Engineering Kyungpook National University Daegu 702-701 Republic of Korea

Two-dimensional reduced graphene oxide-titania （RGO-TiO2） composites were prepared using a single- step hydrothermal method under various hydrothermal reaction conditions. The morphological and surface characteristics of the RGO-TiO2 composites and reference materials were determined. The RGO-TiO2 composites showed photocatalytic activity for the decomposition of two target pollutants that was superior to both pure TiO2 and RGO under fluorescent daylight lamp illumination. The photo- catalytic activity of the RGO-TiO2 composite increased as the hydrothermal treatment time increased from 1 to 24 h, but then it decreased as the time increased to 36 h, which indicated the presence of an optimal treatment time. RGO-TiO2 composites activated by violet light-emitting diodes （LEDs） displayed lower decomposition efficiency than those activated by a daylight lamp, likely because of the lower light intensity of violet LEDs （0.2 mW/cm2） when compared with that of the daylight lamp （1.4mW/cm2）. However, the photocatalytic decomposition of the target pollutants using the RGO-TiO2 composite was more energy-efficient using the violet LEDs. The photocatalytic reaction rates increased as the residence time decreased, whereas the reverse was true for the decomposition efficiency.

关键词： TiO2 composite Continuous-flow mode Hydrothermal time VioletLight emitting diode