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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Chemical Engineering Research
Journal Basic Information
Journal DOI :
The Korean Institute of Chemical Engineers
Editor in Chief :
Volume & Issues
Volume 50, Issue 6 - Dec 2012
Volume 50, Issue 5 - Oct 2012
Volume 50, Issue 4 - Aug 2012
Volume 50, Issue 3 - Jun 2012
Volume 50, Issue 2 - Apr 2012
Volume 50, Issue 1 - Feb 2012
Selecting the target year
Fabrication and Property of Ba
Hollow Fiber Membranes
Jeon, Sung Il ; Park, Jung Hoon ; Kim, Jong Pyo ; Sim, Woo Jong ; Lee, Yong Taek ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 1~5
DOI : 10.9713/kcer.2012.50.1.001
hollow fiber with o.d. 1.02 mm and i.d. 0.437 mm were fabricated by a phase-inversion spinning technique.The starting
precursor was synthesized by the polymerized complex method and then calcined at
. As-prepared powder was dispersed in a polymer solution, and extruded as form of hollow fiber through a spinneret. Finallydense
hollow fiber membrane was obtained by sintering for 2 h at
for the application of oxygen separation. In addition, despite a very thin membrane with 0.58 mm, the BSCF hollow fiber membrane possessed a proper mechanical strength of 602.5 MPa.
Effect of Paraffin Oil on the Low Temperature Adhesion Properties of CR/SBS Modified Asphalt Sealants
Kim, Doo Byung ; Lee, Dae Woo ; Kim, Jong-Seok ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 6~10
DOI : 10.9713/kcer.2012.50.1.006
The main objective of this work was studying the influence of paraffin oil(PO) on the adhesion properties at low temperature in styrene-butadiene-styrene(SBS) copolymer and crumb rubber(CR) modified asphalt. The temperature susceptibility of SBS/CR asphalt and PO/SBS/CR/asphalt blends were measured by penetration and softening point. Adhesion properties at low temperature and dispersion of modifiers in PO/SBS/CR/asphalt blends were evaluated by universal test machine and florescence microscopy, respectively. The adhesion properties of PO/SBS/CR/asphalt blends at low temperature increased in the proportion of SBS contents with both 5 and 10 wt % of paraffin oil. Results showed that the maximum tensile adhesion strength and toughness energy at
were obtained when PO and SBS contents were 10 wt % and 6 wt %, respectively. The addition of PO is effective for enhancing the flexibility of SBS/CR/asphalt blends and leads to the increase of toughness at low temperature.
Disinfection of E.coli in Drinking Water by TiO
Jung, Jin-Ah ; Kwak, Do Hwan ; Oh, Dae Woong ; Park, Dong Min ; Yang, O-Bong ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 11~17
DOI : 10.9713/kcer.2012.50.1.011
Disinfection of Escherichia coli (E. coli) in drinking water was investigated by using
based photocatalyst prepared by sol-gel method. The disinfection test was carried out in an annular flow reactor with circulating sterile water containing the photocatalysts powder under UV-A irradiation. The disinfection activity was proportional to the anatase`s intensity of crystalline peak of the
photocatalysts. 100% disinfection of E.coli without endotoxin was achieved with
coated photocatalytic system under UV-A irradiation within 2 h. However, toxic endotoxine was exist in the disinfection of E.colithe under UV-C irradiation even though 100% disinfection of E.colithe within 30 min, which suggest that
coated photocatalytic system with UV-A is useful tool for the disinfection of E.coli in drinking water.
Characterization of Pretreatment for Barley straw by Alkaline Solutions
Kim, Kyoung-Seob ; Kim, Jun Seok ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 18~24
DOI : 10.9713/kcer.2012.50.1.018
Lignocellulose is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of Agriculture residual biomass, e.q., Barley straw, because of their several superior aspects as Agriculture residual biomass; low lignin, high contents of carbohydrates. Barley straw consists of 39.78% cellulose (glucose), 22.56% hemicelluloses and 19.27% lignin. Pretreatment of barley straw using NaOH pretreatment solutions concentration with 2%, temperature
and reaction times 1 hr were investigates.
pretreatment condition was solutions concentration with 15%, temperature
, and reaction times 24hr were investigates. Furthermore, enzymatic saccharification using cellulose at
, pH 4.8, 180 rpm for conversion of cellulose contained in barley straw to monomeric sugar. The pretreatment of barley straw using NaOH and
can significantly improve enzymatic saccharification of barley straw by extract more lignin and increasing its accessibility to hydrolytic enzymes. The result showed NaOH pretreatment extracted yield of lignin was 24.15%.
pretreatment extracted yield of lignin was 29.09%. Shaccharification of barley straw pretreatment by NaOH for 72hr and pH 4.8 result in maximum glucose concentration 15.39g/L (58.40%) and by
for 72hr and pH 4.8 result in maximum glucose concentration 16.01g/L (64.78%).
Effect of Annealing Temperature on the Anode Properties of TiO
Nanotubes for Rechargeable Lithium Batteries
Choi, Min Gyu ; Kang, Kun Young ; Lee, Young-Gi ; Kim, Kwang Man ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 25~29
DOI : 10.9713/kcer.2012.50.1.025
nanotubes are prepared from rutile prticles via an alkaline hydrothermal synthesis and the consequent heat treatment at
. The physical and electrochemical properties of the
nanotubes are characterized for use as a anode material of rechargeable lithium battery. In particular, the microscale dusts as an impurity component occurred in the purification step after the hydrothermal reaction are completely removed to yield
nanotube with a higher specific surface area and more obvious crystalline phases. As the annealing temperature increases, the specific surface area is slightly decreased due to some aggregation between the isotropically dispersed nanotubes. Highest initial discharge capacity of 250 mAh
is achieved for the
nanotube annealed at
, whereas the
nanotube shows the superior cycle performance and high-rate capability.
Improvement of Tensile Strength of Polyester Resin Using Silica/Chopped Glass Fiber Modified by Coupling Agent
Lee, Jeon-Kyu ; Kim, Si-Young ; Ju, Chang-Sik ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 30~34
DOI : 10.9713/kcer.2012.50.1.030
For the purpose of development of polymeric material for marine applications, the effects of silica and chopped glass fiber on tensile strength of polyester resin were studied. A series of experiments were performed with different contents of silica and chopped glass fiber. Tensile strength of polyester resin was increased with the contents of unmodified glass fiber, and decreased with that of silica. The surfaces of silica and chopped glass fiber were modified with coupling agent at different concentrations, and the modification showed positive effect on the increase of tensile strength of polyester resin. Synergistic effect on the tensile strength of polyester resin was observed by modified silica and chopped glass fiber.
Study of CO
Absorption Characteristic and Synthesis of 1-(2-methoxyethyl)-3-methylimidazoLium Methanesulfonate Ionic Liquid
Jin, Yu Ran ; Jung, Yoon Ho ; Park, So Jin ; Baek, Il Hyun ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 35~40
DOI : 10.9713/kcer.2012.50.1.035
In this study, 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate ionic liquid has been synthesized, characterized and tested with respect to carbon dioxide absorption with the aim to use it as advanced absorbent materials in fossil fuel processing. The ionic liquid was synthesized by a one step method, low cost. The thermal and chemical stability of selected ionic liquid has been investigated by DSC, TGA and the structure was verified by
-NMR spectroscopy. The solubility of carbon dioxide in the methanesulfonate-based ionic liquids were measured using a high-pressure equilibrium apparatus equipped with a variable-volume view cell at 30, 50 and
and pressure up to 195 bar. The results show that carbon dioxide solubilities of 1-(2-methoxyethyl)-3-methylimidazolium methanesulfonate increased with pressure increasing and temperature decreasing, and the carbon dioxide absorption capacity showed 27.6
, 13 bar.
Preparation of Mo-Bi-V-Al Mixed Oxide Catalysts and Its Application to Methanol Synthesis by Partial Oxidation of Methane
Park, Eun-Seok ; Shin, Ki-Seok ; Ahn, Sung-Hwan ; Hahm, Hyun-Sik ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 41~49
DOI : 10.9713/kcer.2012.50.1.041
This study was aimed at the development of catalysts for the direct methanol synthesis by partial oxidation of methane. Mo-Bi-V-Al mixed oxide catalysts were prepared and characterized and used in the direct methanol synthesis reaction. The catalysts prepared by the sol-gel method had much larger surface areas than those prepared by the co-precipitation method. The larger the surface area was, the less the methanol selectivity was. The catalysts having larger surface area facilitate the complete oxidation of methane, decreasing the selectivity of methanol. The catalysts prepared by the sol-gel method showed higher methanol selectivity of 13% at
lower temperature than those prepared by the co-precipitation method. Through XRD analysis, it was revealed that the structures of the catalysts prepared by the two methods were different. In the reaction, methanol selectivity increased and carbon dioxide selectivity decreased with pressure due to the suppression of complete oxidation reaction at a high pressure.
Preparation and Electrochemical Properties of PANI/TiO
Composites for Supercapacitor Electrodes
Park, Sukeun ; Kim, Kwang Man ; Lee, Young-Gi ; Jung, Yongju ; Kim, Seok ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 50~54
DOI : 10.9713/kcer.2012.50.1.050
In this study, PANI and PANI/
composites were prepared as electrode materials for a supercapacitor application. Cyclic voltammetry (CV) was performed to investigate the supercapacity properties of these electrodes in an electrolyte solution of 6 M KOH. The PANI/
composites were polymerized by amount of various ratios through a simple in-situ method. The morphological properties of composites were analyzed by SEM and TEM method. The crystallinity of the composite and
particle size were identified using X-ray diffraction (XRD). In the electrochemical test, The electrode containing 10 wt%
content against aniline units showed the highest specific capacitance (626
) and delivered a capacitance of 286
reversibly at a 100
rate. According to the surface morphology, the increased capacitance was related to the fact that nano-sized
particles (~6.5 nm) were uniformly connected for easy charge transfer and an enhanced surface area for capacitance reaction of
Energy Conservation and Exergy Comparison of a Fully Thermally Coupled Distillation Column
Kim, Byoung Chul ; Kim, Young Han ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 55~60
DOI : 10.9713/kcer.2012.50.1.055
The energy conservation and exergy loss of a fully thermally coupled distillation commercialized as the divided wall column are compared with those of a conventional two-column system for ternary separation. The used example for the comparison is the benzene-toluene-m-xylene separation process widely used in a petrochemical plant. The design procedure of the fully thermally coupled distillation column is explained, and the energy requirement is compared using the HYSYS. When the same numbers of trays are utilized, the fully thermally coupled distillation column uses 28.2% less energy and 10.4% more exergy loss. The increase of the exergy loss is due to the additional mixing from the bidirectional inter-linking and the temperature elevation in the reboiler from the increased pressure at the bottom of the main column.
Linear Stability of Compositional Convection in a Mushy Layer during Solidification of Ammonium Chloride Solution
Hwang, In Gook ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 61~65
DOI : 10.9713/kcer.2012.50.1.061
The onset of convection in a mushy layer is analyzed by using linear stability theory in time-dependent solidification of a binary melt. A simplified model of a near-eutectic mush, in which the mush is assumed to be a porous block, is used and the propagation theory is applied to determine the critical conditions for the onset of convection. The present critical Rayleigh number is higher than the existing experimental result and also theoretical results obtained by considering the mushy layer with an overlying liquid layer. The constant pressure (permeable) condition applied on the mush-liquid interface produces a lower critical Rayleigh number, which is closer to the experimental results of aqueous ammonium chloride solution, compared with the impermeable condition.
Permeability of Viscous Flow Through Packed Bed of Bidisperse Hard Spheres
Sohn, Hyunjin ; Koo, Sangkyun ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 66~71
DOI : 10.9713/kcer.2012.50.1.066
We deal with a problem to determine experimentally as well as theoretically permeability of incompressible viscous flow through packed bed of bidisperse hard spheres in size. For the size ratios of large to small spheres
=1.25 and 2, we set up bidisperse packing and measured porosity and permeability at various volumetric ratios of small to large spheres
. Bidisperse packing shows lower porosity and permeability than monodisperse packing does. Variation of porosity as a function of
does not match with that of permeability. A theoretical expression for predicting permeability of a viscous flow for packed bed of bidisperse packing is derived based on calculation of drag force acting on each sphere and its predictions are compared with the experimental data and those from some relations previously suggested. It is found that our theory shows better agreement with experimental results than the previous studies and is proved to be quite simple and accurate in estimating the permeability.
Strain-free AlGaN/GaN Nanowires for UV Sensor Applications
Ahn, Jaehui ; Kim, Jihyun ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 72~75
DOI : 10.9713/kcer.2012.50.1.072
In our experiments, strain-free nanowires(NWs) were dispersed on to the substrate, followed by e-beam lithography(EBL) to fabricate single nanowire ultraviolet(UV) sensor devices. Focused-ion beam(FIB), micro-Raman spectroscopy and photoluminescence were employed to characterize the structural and optical properties of AlGaN/GaN NWs. Also, I-V characteristics were obtained under both dark condition and UV lamp to demonstrate AlGaN/GaN NW-based UV sensors. The conductance of a single AlGaN/GaN UV sensor was 9.0
(under dark condition) and 9.5
(under UV lamp), respectively. The currents were enhanced by excess carriers under UV lamp. Fast saturation and decay time were demonstrated by the cycled processes between UV lamp and dark condition. Therefore, we believe that AlGaN/GaN NWs have a great potential for UV sensor applications.
A Kinetic Study of Steam Gasification of Rice Straw, Saw Dust Biomass and Coal
Song, Byungho ; Zhu, Xueyan ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 76~82
DOI : 10.9713/kcer.2012.50.1.076
Biomass and coal are great potential energy sources for gasification process. These solids can be gasified to produce syngas and bio-oil which can be upgraded further to transportation fuel. Two biomass and three coals have been gasified with steam in a thermobalance reactor under atmospheric pressure in order to evaluate their kinetic rate information The effects of gasification temperature (
) and partial pressure of steam (30~90 kPa) on the gasification rate have been investigated. The three different types of gas-solids reaction models have been applied to the experimental data to compare their predictions of reaction behavior. The modified volumetric reaction model predicts the conversion data well, thus that model was used to evaluate kinetic parameters in this study. The gasification reactivity of five solids has been compared. The obtained activation energy of coal and biomass gasification were well in the reasonable range. The expression of apparent reaction rates for steam gasification of five solids have been proposed as basic information for the design of coal gasification processes.
Removal of Trihalomethanes from Tap Water using Activated Carbon Fiber
Yoo, Hwa In ; Ryu, Seung Kon ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 83~87
DOI : 10.9713/kcer.2012.50.1.083
Activated carbon fiber (ACF) was used to remove four kinds of trihalomethanes(THMs) from tap water which were remained as by-products during the chlorination of water. Adsorption capacity was investigated as a function of THMs concentration and solution temperature, and adsorption mechanism was studied in relating to the surface characteristics of ACF. All the four kinds of THMs were rapidly adsorbed on the surface of ACF by physical adsorption due to the enormous surface micropores and chemical adsorption due to the hydrogen bonds, showing a Langmuir type adsorption isotherm. Langmuir type is especially profitable for the adsorption of low level adsorptives. ACF was very effective for the removal of THMs from tap water because the THMs concentration is below
in tap water. The adsorption amount of THMs on ACF increased in order of the number of brom atom; chloroform, bromodichloromethane, dibromochloromethane, and bromoform. The adsorption capacity increased as increasing the number of brom atom due to the decrease of polarity in solution. The adsorption capacity of THMs on ACF can be enhanced by proper surface treatment of ACF.
Recycling of Crosslinked Polypropylene and Crosslinked Polyethylene in Supercritical Methanol
Lee, Hong-Shik ; Jeong, Ju Hyeong ; Hong, Soon Man ; Koo, Chong Min ; Cho, Hang-Kyu ; Lee, Youn-Woo ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 88~92
DOI : 10.9713/kcer.2012.50.1.088
Decrosslinking of crosslinked polypropylene(XLPP) in supercritical methanol was investigated compared with that of crosslinked polyethylene(XLPE). Effect of reaction temperature and initial gel contents was studied using a batch reactor. Gel contents of samples before and after reaction were measured for quantitative analysis. As reaction temperature and initial gel contents increased, the decrosslinking rate increased. The rate of decrosslinking reaction is dependent linearly on the gel contents. Experimental results indicated that the decrosslinking of XLPP was faster than that of XLPE, and it was confirmed quantitatively by the calculation of kinetic constants. In conclusion, it is considered that XLPP has better recyclability than XLPE.
Modeling and Measurements of the Activity Coefficients and Solubilities of Amino Acids in the L-valine/electrolyte and L-proline/electrolyte Aqueous Solutions
Lee, Bong-Seop ; Kim, Ki-Chang ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 93~105
DOI : 10.9713/kcer.2012.50.1.093
Activity coefficients and solubilities of L-Valine and L-Proline in aqueous solutions containing each of four electrolytes such as NaCl, KCl,
were measured at 298.15 K. The measurements of activity coefficients were carried out in the electrochemical cell coupled with two ion-selective electrodes (cation and anion), and the solubilities were measured by the gravimetric analysis of saturated solutions in equilibrium with the solid phase of amino acid. The measured activity coefficients of electrolytes and amino acids were correlated with the theoretical thermodynamic model presented in the previous work [Korean Chem. Eng. Res. 48(4), 519(2010)]. It was found that the activity coefficients of amino acids and electrolytes described based on the our previous model were well agreeable with experimental data. Also the experimental solubility data of L-Valine and L-Proline were successfully correlated with the thermodynamic relation mentioned in the previous work.
Drying Characteristic of High Moisture Coal using a Flash Dryer
Kim, Sang Do ; Lee, Si Hyun ; Rhim, Young Joon ; Choi, Ho Kyung ; Lim, Jeong Hwan ; Chun, Dong Hyuk ; Yoo, Ji Ho ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 106~111
DOI : 10.9713/kcer.2012.50.1.106
Drying characteristic of high moisture coal using a 5 kg/hr bench scale flash dryer was investigated. Moisture content and heating value of raw coal as received basis were 29.74 wt% and 4,270 kcal/kg, respectively. Gas inlet temperature and gas inlet flow rate were
and 10~20 m/sec, respectively. The raw coal was ground and classified to the particle size range of
. The moisture removal rate of raw coal was dramatically increased with increasing gas inlet temperature and decreasing gas inlet flow rate. The heating value of dried coal was increased to 5,100~5,900 kcal/kg. To examine the chemical change on the surface of high moisture coal during flash drying process, FT-IR spectral analysis was carried out. As a result, major changes in hydroxyl, carboxyl and carbonyl peak was confirmed.
Nano-safety Management and Exposure Assessment of Nanomaterials Producing Facilities
Umh, Ha Nee ; Roh, Jinkyu ; Park, Junsu ; Kwak, Byoung Kyu ; Lee, Byung Cheon ; Choi, Kyunghee ; Yi, Jongheop ; Kim, Younghun ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 112~117
DOI : 10.9713/kcer.2012.50.1.112
With the development of nanotechnology, nano-consumer products have been popularized. For the past 10 years, potential risk of nanomaterials to human and environment have been raised carefully. Especially, workers, who directly handle nanomaterials in laboratories and manfacturers, will lead to direct exposure of nanomaterials. Therefore, direct exposure assessment and field monitoring of nanomaterials are required to assess and manage the nanomaterial exposure to human and environment. In this work, two nano-manufacturing companies, which had plasma and sol-gel processes, were selected to analyze the main exposure source and process with in-situ SMPS (scanning mobility particle sizer) and ex-situ TEM (transmission electron microscopy). The results showed that the colloidal nanoparticle in liquid phase was easily evaporated and monitored by SMPS. Most serious thing is that the workers does not know about the potential risk of nanomaterials, and thus they are not taking proper protection activities, such as PPE (personal protective equipment). Therefore, exposure assessment for nanomaterial handling facilities should be additionally carried out, and nano-safety management protocols are also provided.
Analysis of Corrosion Characteristics for TiN- and Ti/TiN-coated Stainless Steel Bipolar Plate in PEMFC
Han, Choonsoo ; Chae, Gil-Byung ; Lee, Chang-Rae ; Choi, Dae-Kyu ; Shim, Joongpyo ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 118~127
DOI : 10.9713/kcer.2012.50.1.118
TiN or Ti/TiN was coated on stainless steel as bipolar plate in polymer electrolyte membrane fuel cells (PEMFCs) to improve their corrosion resistance and electric conductivity, and their properties were examined under fuel cell operating condition. After 200 hours operation, the behaviors for the corrosion, crack and dissolution of coating layer were investigated by various techniques. The corrosion and exfoliation of coating layer were considerably generated except for SUS316L-Ti/TiN after fuel cell operation even if the electric conductivity and corrosion resistance of coated stainless steel bipolar plates were improved. The adoption of Ti layer between TiN layer and the surface of stainless steel enhanced the adhesion of TiN layer and decreased the possibility of corrosion by the increase of coating layer.
The Operational Characteristics of CO
5 ton/day Absorptive Separation Pilot Plant
O, Min-Gyu ; Park, So-Jin ; Han, Keun-Hee ; Lee, Jong-Seop ; Min, Byoung-Moo ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 128~134
DOI : 10.9713/kcer.2012.50.1.128
The pilot scale experiments can handle the flue gas up to 1,000
for separation of carbon dioxide included in real flue gas at coal-fired power plant. The operational characteristics was analyzed with the main experimental variables such as flue gas flow rate, absorbent circulation rate using chemical absorbents mono-ethanolamine( MEA) and 2-amino-2-methyl-1-propanol(AMP). The more flue gas flow rate decreased in 100
in the MEA 20 wt% experiments, the more carbon dioxide removal efficiency was increased 6.7% on average. Carbon dioxide removal efficiency was increased approximately 2.8% according to raise of the 1,000 kg/hr absorbent circulation rate. It also was more than 90% at
of re-boiler temperature. Carbon dioxide removal efficiency of the MEA was higher than that of the AMP. In the MEA(20 wt%) experiment, carbon dioxide removal efficiency(85.5%) was 10% higher than result(75.5%) of ASPEN plus simulation.
Analysis of the Heat of Absorption Based on the Chemical Structures of Carbon Dioxide Absorbents
Kwak, No Sang ; Lee, Ji Hyun ; Eom, Yong Seok ; Kim, Jun Han ; Lee, In Young ; Jang, Kyung Ryoung ; Shim, Jae-Goo ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 135~140
DOI : 10.9713/kcer.2012.50.1.135
In this study, the heats of absorption of
with aqueous solutions of primary, secondary and tertiary amine aqueous solutions were measured in the commercial reaction calorimeter SIMULAR (HEL, UK). The heats of absorption of 30 wt% amine aqueous solutions of MEA (monoethanolamine, primary amine), EAE(2-(ethylamino)ethanol, secondary amine), and MDEA (methyldiethanolamine, tertiary amine) were measured as function of the
loading ratio at
, in each case. In addition, the heats of absorption of sterically-hindered amine aqueous solutions of AMP(2-amino-2-methyl-1-propanol, primary amine), DEA(diethanolamine, secondary amine) and TEA(triethanolamine, tertiary amine) were measured to observe the steric hindrance effect. The heat of absorption is high in the following order regardless of the steric hindrance: primary amine > secondary amine > tertiary amine. The heats of absorption of amines having sterically-hindered substituents surrounding nitrogen atoms are relatively low compare to that of sterically-free amines, although the difference is very small.
Characteristics of Acid-hydrolysis and Ethanol Fermentation of Laminaria japonica
Na, Choon-Ki ; Song, Myoung-Ki ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 141~148
DOI : 10.9713/kcer.2012.50.1.141
In order to study the utilization of brown seaweed Laminaria japonica as an alternative renewable feedstock for bioethanol production, the properties of acid hydrolysis and ethanol fermentation were investigated. The acid hydrolysis enhanced the final yield of fermentable sugars, which led great increase of ethanol productivity. The maximum yield of reducing sugars reached 135 mg/g-dry Laminaria japonica after 1.0N sulfuric acid-hydrolysis at
for 6 h. The Saccharomyces cerevisiae (ATCC 24858) could ferment
-sugars like glucose, galactose and mannose into ethanol, but not
-sugars like arabinose and xylose. Optimal fermentation time varied with sugars; 48 h for glucose, 72 h for galactose, and 96 h for mannose. Nevertheless, the ethanol yield from the hydrolysate reached 242 mg/g-dry Laminaria japonica after fermentation by the S. cerevisiae at
for 96 h, which corresponds to approximately 4 times more than the theoretical yield from total reducing sugars in the hydrolysates. It indicates that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. The ethanol concentration linearly increased from 2.4 to 9.2 g/L, while the ethanol yield per dry weight of biomass decreased from 242 to 185 mg/g, with increasing the ratio of biomass to acid solution from 1 to 5% (w/v). The bioethanol yield estimated was approximately 7,400~9,600 kg/ha/year, and indicated that Laminaria japonica is a promissing feedstock for bioethanol production.
Biofilter Model for Robust Biofilter Design: 1. Adsorption Behavior of the Media of Biofilter
Lee, Eun Ju ; Seo, Kyo Seong ; Jeon, Wui-Sook ; Lim, Kwang-Hee ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 149~154
DOI : 10.9713/kcer.2012.50.1.149
The adsorption and desorption behavior of biofilter-medium was investigated on the performance of an adsorption column. Continuous flow-isothermal adsorption experiments were performed to treat waste air containing such a VOC as ethanol under the same condition of > 90% relative humidity as the condition of the feed to a biofilter process. In case of feeding waste air containing ethanol of 1,000 ppmv (or 2,050 mg ethanol/
) to the adsorption system at the rate of 2 L/min, the onsets of its breakthrough and reaching the state of dynamic equilibrium at the exit had been delayed 10 and 3 times, respectively, later than those at the 1st stage sampling port. Moreover, in case of 2,000 ppmv (or 4,100 mg ethanol/
), they had been delayed 9 and 3 times, respectively. Thus, regardless of feeding concentration, the ratios of delaying period were observed to be quite consistent each other at the exit of the adsorption column. With regard to the period of desorption, the ratios of delaying period were consistent each other to be 1.5 for both cases. In addition, the effect of microbial activity and sterilization-process was studied on adsorption equilibrium. The ethanol concentration in the vapor phase of vials packed with sterilized granular activated carbon (GAC) was quite consistent to that with unsterilized GAC. However, the ethanol concentrations in the vapor phase of vials packed with unsterilized compost and the unsterilized mixture of GAC and compost were higher than those with sterilized compost and the sterilized mixture of GAC and compost, respectively.
Biofilter Model for Robust Biofilter Design: 2. Dynamic Biofilter Model
Lee, Eun Ju ; Song, Hae Jin ; Lim, Kwang-Hee ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 155~161
DOI : 10.9713/kcer.2012.50.1.155
A dynamic biofilter model was suggested to integrate the effect of biofilter-medium adsorption capacity on the removal efficiency of volatile organic compound (VOC) contained in waste air. In particular, the suggested biofilter model is composed of four components such as biofilm, gas phase, sorption volume and adsorption phase and is capable of predicting the unsteady behavior of biofilter-operation. The process-lumping model previously suggested was limited in the application for the treatment of waste air since it was derived under the assumption that the adsorbed amount of VOC equilibrated with biofilter-media would be proportional to the concentration of dissolved VOC in the sorption volume of biofilter-media. Therefore a Freundlich adsorption isotherm was integrated into a robust biofilter process-lumping model applicable to a wide range of VOC concentration. The values of model parameters related to biofilter-medium adsorption were obtained from the dynamic adsorption column experiments in the preceding article and literature survey. Furthermore a separate biofilter experiment was conducted to treat waste air containing ethanol and the experimental result was compared with the model predictions with various values of Thiele modulus (
). The obtained value of Thiele modulus (
) was close to 0.03.
Fabrication of ZnO Rod by Electrodeposition and Its Application to Dye Sensitized Solar Cell
Kim, Hyeyoung ; Jo, Yunkyoung ; Lee, Kiyoung ; Lee, Inhae ; Tak, Yongsug ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 162~166
DOI : 10.9713/kcer.2012.50.1.162
High density of ZnO nanorods were fabricated by electrochemical deposition and subsequent heat treatment. Formation of
and ZnO during electrodeposition indicated that the electrodeposition efficiency of ZnO was below 33%. ZnO rod has a preferential (200) growth plane after heat treatment at
and the growth rate of ZnO rod was measured to be 0.986
. Dye sensitized solar cell(DSC) showed the efficiency of 0.21% when electrochemically prepared ZnO rod was used as an electrode. It suggests the possible application of ZnO rod structure in the DSC.
Thermal Properties of the Themoplastic Elastomers Based on EPDM Ionomer/Polyamide-6 Blends
Jin, Sung-Hoon ; Song, Gwang Seok ; Lee, Dai-Soo ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 167~172
DOI : 10.9713/kcer.2012.50.1.167
A new type of thermoplastic elastomer (TPE) based on EPDM ionomer as an elastomer and polyamide-6 as a reinforcing crystalline polymer was prepared and the thermal properties of TPEs were investigated. Especially effects of neutralization of maleated EPDM (MA-EPDM) to prepare EPDM ionomer with zinc oxide and the content of polyamide-6 on the thermal properties of the blends were investigated. Both the neutralization and blending were carried out employing a twin screw extruder. It was found that the neutralization of MA-EPDM results in the increase of cooling crystallization temperatures. Polyamide-6 plays the role of reinforcing filler in the blends due to the high crystallinity. Fine dispesion of polyamide-6 in the blends was confirmed and attributed to the imide formation between the maleic anhydride of MA-EPDM and amine group of polyamide-6. TPEs based on EPDM ionomer/Polyamide-6 blends showed balanced mechanical properties with improvement in heat resistance.
Development of System on the Sustained Production of Chlorine Dioxide Using Polymer Hydrogels
Jeon, Younghyun ; Kim, Bumsang ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 173~176
DOI : 10.9713/kcer.2012.50.1.173
Chlorine dioxide has an excellent ability to sterilize and deodorize and is harmless to humans. However, it is very unstable and explosive as it is highly concentrated, thus its use in the air clean filed has been limited. Therefore, there is a demand to develop the system to produce a low concentration of chlorine dioxide sustainedly. Here, for a first step in the development of the system on the sustained production of chlorine dioxide, the use of polymer hydrogels was investigated. P(MMA-co-HEMA) hydrogel particles were prepared via dispersion photopolymerization and sodium chlorite and citric acid were loaded respectively in the hydrogel particles. When sodium chlorite and citric acid were reacted with not loaded in the hydrogels, rapid production of chlorine dioxide occurred and the concentration of chlorine dioxide decreased over time. However, when sodium chlorite and citric acid were loaded respectively in the hydrogel particles and reacted, chlorine dioxide was produced slowly and sustainedly because the release of sodium chlorite and citric acid from the hydrogels delayed the reaction between them. The result shows that the use of P(MMA-co HEMA) hydrogels has the potential to develop the system on the sustained production of chlorine dioxide.
Dye-Sensitized Solar Cell Based on TiO
-Graphene Composite Electrodes
Battumur, T. ; Yang, Wooseung ; Ambade, S.B. ; Lee, Soo-Hyoung ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 177~181
DOI : 10.9713/kcer.2012.50.1.177
Dye-sensitized solar cells(DSSCs) based on
film photo anode incorporated with different amount of grapheme nanosheet(GNS) are fabricated and their photovoltaic performance are investigated. The
-GNS composite electrode has been prepared by a direct mixing method. The DSSC performance of this composite electrode was measured using N3 dye as a sensitizer. The performance of DSSCs using the
-GNS composite electrodes is dependent on the GNS loading in the electrodes. The results show that the DSSCs incorporating 0.01 wt% GNS in
photo anode demonstrates a maximum power conversion efficiency of 5.73%, 26% higher than that without GNS. The performance improvement is ascribed to increased N3 dye adsorption, the reduction of electron recombination and back transport reaction as well as enhancement of electron transport with the introduction of GNS. The presence of both
(anatase) and GNS has been confirmed by FieldEmission Scanning Electron Microscopy(FE-SEM). The decrease in recombination due to GNS in DSSCs has been investigated by the Electrochemical Impedance Spectroscopy.
Preparation of Visible-light Active TiO
Nanotubes by Solution Method
Lee, Hyun-Mi ; So, Won-Wook ; Baeg, Jin-Ook ; Kong, Ki-Jeong ; Moon, Sang-Jin ;
Korean Chemical Engineering Research, volume 50, issue 1, 2012, Pages 182~185
DOI : 10.9713/kcer.2012.50.1.182
nanotubes have been newly prepared by two stage sol-gel and strong-alkali hydrothermal process using
and hydrazine/ammonia aqueous solution as raw materials. These nanotubes revealed a well developed anatase crystalline phase and perfect nanotube morphology with the diameter around 10nm and the wall thickness below 3 nm. Also, they showed a superior visible light activity and yellowish color due to the light absorption redshifted by ~35 nm and ~25 nm compared to undoped
nanotubes and anatase nanoparticles, respectively.