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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Chemical Engineering Research
Journal Basic Information
Journal DOI :
The Korean Institute of Chemical Engineers
Editor in Chief :
KIM JAE JEONG
Volume & Issues
Volume 53, Issue 6 - Dec 2015
Volume 53, Issue 5 - Oct 2015
Volume 53, Issue 4 - Aug 2015
Volume 53, Issue 3 - Jun 2015
Volume 53, Issue 2 - Apr 2015
Volume 53, Issue 1 - Feb 2015
Selecting the target year
Shampoo Characteristics of Botanical Extract Containing Green Tea, Saururus chinensis and Prunus padus
Hwang, Danbi ; Shin, Hyejin ; Jeong, Hyangli ; Noh, Daeyoung ; Kim, Misung ; Kim, Jinhong ; Kim, Donguk ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 663~666
DOI : 10.9713/kcer.2015.53.6.663
In this research, botanical extracts containing green tea, Saururus chinensis and Prunus padus were tested to see possibility as shampoo. Leaves of Green tea and Saururus chinensis were extracted with hot water. Prunus padus bark extract was applied reverse osmosis and ultrasonic extraction. When interfacial tension was measured among shampoo including botanical extracts, Sodium dodecylsulfate(SDS) and Quillaja Bark Saponin(QBS), that of shampoo was lower than that of SDS and QBS at lower concentration, however, it showed similar interfacial tension at 100% concentration. Shampoo showed moderate antimicrobial activity in Staphylococcus aureus and Candida albicans. Botanical extract did not indicate cell toxicity up to
concentration in MTT assay. Shampoo containing botanical extract was stable for 3 months, however, it showed considerable variation in pH and viscosity. In conclusion, shampoo containing botanical extract shows strong possibility for natural shampoo if the formulation is modified.
Effect of Fabrication Method of Anode on Performance in Enzyme Fuel Cells
Lee, Se-Hoon ; Hwang, Byung-Chan ; Lee, Hye-Ri ; Kim, Young-Sook ; Chu, Cheun-Ho ; Na, Il-Chai ; Park, Kwon-Pil ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 667~671
DOI : 10.9713/kcer.2015.53.6.667
Enzyme fuel cells were operated with cells composed of enzyme anode and PEMFC cathode. Enzyme anodes was fabricated by compression of a mixture of graphite particle, glucose oxidase(Gox) as a enzyme and ferrocene as a redox mediator, and then coated with Nafion ionomer solution. Performances of enzyme unit cell were measured with variation of anode manufacture factors, to find optimum condition of enzyme anode. Optimum pressure was 8.89MPa for enzyme anode pressing process. Highest power density was obtained at 60% graphite composition in enzyme anode. Optimum glucose concentration was 1.7 mol/l in anode substrate solution. The enzyme anode was stabilized by two times of deeping in Nafion solution for 1 sec.
Phase Asymmetry Effect on Vesicle Fusion Induced by Phospholipase D
Park, Jin-Won ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 672~676
DOI : 10.9713/kcer.2015.53.6.672
Spherical phospholipid bilayers, vesicles, were formed with respect to phase of each layer via a double emulsion technique. The conversion of phosphatidylcholine (PC) to phosphatidic acid (PA) at the outer layer, caused by phospholipase D (PLD), induced a curvature change in the vesicles, which eventually led them to fuse each other. The effect of the lipid layer physical-properties on the PLD-induced vesicle fusion was investigated using the fluorescence intensity change. 8-Aminonaphthalene-1,3,6-trisulfonic acid disodium salt(ANTS) and p-Xylene-bis(N-pyridinium bromide)(DPX) were encapsulated in the vesicles, respectively, for the quantification of the fusion. The fluorescence scale was calibrated with the fluorescence of a 1/1 mixture of ANTS and DPX vesicles in NaCl buffer taken as 100% fluorescence (0% fusion) and the vesicles containing both ANTS and DPX as 0% fluorescence (100% fusion), considering the leakage into the medium studied directly in a separate experiment using vesicles containing both ANTS and DPX. It was observed that the fusion occurred to the liquid-phase of the inner layer only. The fusion behaviors were very similar for both solid and liquid of the outer layer. However, the leakage was faster for the solid-phase outer-layer than the liquid-phase outer-layer. The difference in the leakage seems to be caused by the lipid concentration and the lateral diffusivity in the layer.
Characteristics of Al Alloy as a Material for Hydrolysis Reactor of NaBH
Jung, Hyeon-Seong ; Oh, Sung-June ; Jeong, Jae-Jin ; Na, Il-Chai ; Chu, Cheun-Ho ; Park, Kwon-Pil ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 677~681
DOI : 10.9713/kcer.2015.53.6.677
Aluminum alloy was examined as a material of low weight reactor for hydrolysis of
. Aluminum is dissolved with alkali, but there is NaOH as a stabilizer in
solution. To decrease corrosion rate of aluminum, decrease NaOH concentration and this result in loss of
during storage of
solution. Therefore stability of
and corrosion of aluminum should be considered in determining the optimum NaOH concentration.
stability and corrosion rate of aluminum were measured by hydrogen evolution rate.
stability was tested at
and aluminum corrosion was measured at
. The optimum concentration of NaOH was 0.3 wt%, considering both
stability and aluminun corrosion.
hydrolysis reaction continued 200min in aluminum No 6061 alloy reactor with 0.3 wt% NaOH at
Recovery of Xylo-oligomer and Lignin Liquors from Rice Straw by Two 2-step Processes Using Aqueous Ammonia Followed by Hot-water or Sulfuric Acid
Vi Truong, Nguyen Phuong ; Shrestha, Rubee koju ; Kim, Tae Hyun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 682~689
DOI : 10.9713/kcer.2015.53.6.682
A two-step process was investigated for pretreatment and fractionation of rice straw. The two-step fractionation process involves first, soaking rice straw in aqueous ammonia (SAA) in a batch reactor to recover lignin-rich hydrolysate. This is followed by a second-step treatment in a fixed-bed flow-through column reactor to recover xylo-oligomer-rich hydrolysate. The remaining glucan-rich solid cake is then subjected to an enzymatic process. In the first variant, SAA treatment in the first step dissolves lignin at moderate temperature (60 and
), while in the second step, hot-water treatment is used for xylan removal at higher temperatures (
). Under optimal conditions (
reaction temperature, 30 min reaction time, 5.0 ml/min flow rate, and 2.3 MPa reaction pressure), the SAA-hot-water fractionation removed 79.2% of the lignin and 63.4% of the xylan. In the second variant, SAA was followed by treatment with dilute sulfuric acid. With this process, optimal treatment conditions for effective fractionation of xylo-oligomer were found to be
, 12 h reaction time, solid-to-liquid ratio of 1:12 in the first step; and 5.0 ml
, and 2.3 MPa in the second step. After this two-step fractionation process, 85.4% lignin removal and 78.9% xylan removal (26.8% xylan recovery) were achieved. Use of the optimized second variant of the two-step fractionation process (SAA and
) resulted in enhanced enzymatic digestibility of the treated solid (99% glucan digestibility) with 15 FPU (filter paper unit) of CTec2 (cellulase)/g-glucan of enzyme loading, which was higher than 92% in the two-step fractionation process (SAA and hot-water).
Characteristics of sPAES Membrane and sPEEK Membrane for Direct Formic Acid Fuel Cell
Jeong, Jae-Hyeon ; Song, Myung-Hyun ; Chung, Hoi-Bum ; Lee, Moo-Seok ; Lee, Dong-Hoon ; Chu, Cheun-Ho ; Na, Il-Chai ; Park, Kwon-Pil ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 690~694
DOI : 10.9713/kcer.2015.53.6.690
Recently, direct formic acid fuel cells (DFAFC) among direct liquid fuel cells is studied actively. Economical hydrocarbon membranes alternative to fluorinated membranes for DFAFC's membrane are receiving attention. In this study, characteristics of sulfonated poly(ether ether ketone, sPEEK) and sulfonated poly(arylene ether sulfone, PAES) membranes were compared with Nafion membrane at DFAFC operation condition. Formic acid crossover current density of hydrocarbon membranes were lower than that of Nafion 211 fluorinated membrane. I-V performance of sPEEK MEA(Membrane and Electrode Assembly) was similar to that of Nafion 211 MEA due to similar membrane resistance each other. sPEEK MEA with low formic acid crossover showed higher stability compared with Nafion 211 MEA.
Recovery of Acetic Acid from An Ethanol Fermentation Broth by Liquid-Liquid Extraction (LLE) Using Various Solvents
Pham, Thi Thu Huong ; Kim, Tae Hyun ; Um, Byung-Hwan ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 695~702
DOI : 10.9713/kcer.2015.53.6.695
Liquid-liquid extraction (LLE) using various solvents was studied for recovery of acetic acid from a synthetic ethanol fermentation broth. The microbial fermentation of sugars presented in hydrolyzate gives rise to acetic acid as a byproduct. In order to obtain pure ethanol for use as a biofuel, fermentation broth should be subjected to acetic acid removal step and the recovered acetic acid can be put to industrial use. Herein, batch LLE experiments were carried out at
using a synthetic fermentation broth comprising
acetic acid and
ethanol. Ethyl acetate (EtOAc), tri-n-octylphosphine oxide (TOPO), tri-n-octylamine (TOA), and tri-n-alkylphosphine oxide (TAPO) were utilized as solvents, and the extraction potential of each solvent was evaluated by varying the organic phase-to-aqueous phase ratios as 0.2, 0.5, 1.0, 2.0, and 4.0. The highest acetic acid extraction yield was achieved with TAPO; however, the lowest ethanol-to-acetic acid extraction ratio was obtained using TOPO. In a single-stage batch extraction, 97.0 % and 92.4 % of acetic acid could be extracted using TAPO and TOPO when the ratio of organic-to-aqueous phases is 4:1 respectively. A higher solvent-to-feed ratio resulted in an increase in the ethanol-to-acetic acid ratio, which decreased both acetic acid purity and acetic acid extraction yield.
Mechanical Properties of Carbon Nanotube/Polyurethane Nanocomposites via PPG Dispersion with MWCNTs
Kim, Dae Won ; Kim, Jong Seok ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 703~708
DOI : 10.9713/kcer.2015.53.6.703
In order to improve the dispersity of nanofiller, polyurethane (PU) nanocomposites were manufactured via poly(propylene gylcol) (PPG) dispersion with MWCNTs prepared by using a ball mill shaker. MWCNTs could be functionalized by treating with the hydrogen peroxide (
). Tensile strengths and elongations at break of
treated MWCNTs nanocomposites were enhanced compared to those of the PU/pristine MWCNTs nanocomposites. The good dispersion of MWCNTs shown in SEM images was obtained by the functionalization of MWCNTs surface. PU/carbon black (CB) composites showed no significant change in the tensile properties. The tensile properties of PU nanocomposites containing pristine MWCNTs or
treated MWCNTs were enhanced with increasing dispersion time. As a result, it was certified that the enhanced dispersity of nanofiller brought the improvement of the tensile properties of the MWCNTs based PU nanocomposites.
Rheology and Morphology of PP/ionomer/clay Nancomposites Depending on Selective Dispersion of Organoclays
Kim, Doohyun ; Ock, Hyun Geun ; Ahn, Kyung Hyun ; Lee, Seung Jong ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 709~716
DOI : 10.9713/kcer.2015.53.6.709
In this study, structural developments of polypropylene / ionomer / clay ternary composites were investigated depending on the dispersion and localization of clay. The changes in physical properties were observed adding organoclays 1~10wt% to 90% polypropylene and 10% ionomer blends. The organoclays were localized inside of the dispersed phase under the composition of 3wt%, however, over that composition, clay particles formed stiff network structure in the dispersed phase and additional clays were localized at the interface between two phases. According to the developments of microstructure, the interaction of ternary composites changed from polypropylene-ionomer to polypropylene-ionomer and ionomer-clay which affected rheological properties. The storage modulus (G') of the composites was similar to the blends when clays were localized inside of dispersed phase but increased when clays were localized at interface. Also, the fractured morphology of the composites showed phase boundary and growing radius of dispersed phase depending on addition of fillers when clays were found inside. However, when fillers found at the interface between blends, the radius of the dispersed phase decreased and compatibilized morphology were observed. The interfacial interaction of the ternary composite was quantified depending on the structural development of dispersed phase and localization of clay particles by the rheological properties. The interaction of composites at solid state which was measured through peel adhesion strength increased by growth of interfacial interaction of each component. Furthermore, the crystallinity of the composites was decreased when the clay particles were localized at the interface.
Optimization of d-limonene Extraction from Tangerine Peel in Various Solvents by Using Soxhlet Extractor
Park, Sang Min ; Ko, Kwan Young ; Kim, In Ho ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 717~722
DOI : 10.9713/kcer.2015.53.6.717
D-limonene included in citrus fruits is obtainable to extract essential oil as well as separate the oil ingredient. Soxhlet extraction, a type of SDE (Simultaneous steam Distillation and solvent Extraction), was used to extract limonene from tangerine peel. HPLC analysis was performed to quantify extracted d-limonene by using reversed-phase HPLC column. Results of HPLC analysis showed that the optimal extraction time was 2 hours in any solvent, and the extracted amounts of d-limonene in tangerine peel (per g tangerine peel) were 7.77 mg, 0.49 mg, and 0.28 mg in ethyl alcohol, n-hexane, and ether. Because yield was the highest in using ethyl alcohol as a solvent, polarity is stronger factor to effect on yield of extraction than boiling point.
Analysis of Cyclic Adenosine Monophosphate (cAMP) Separation via RP-HPLC (reversed-phase high-performance liquid chromatography) by the Moment Method and the van Deemter Equation
Lee, Il Song ; Ko, Kwan Young ; Kim, In Ho ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 723~729
DOI : 10.9713/kcer.2015.53.6.723
The moment analysis of cyclic adenosine monophosphate (cAMP) was performed using chromatograms that were obtained with the pulse input method from an octadecyl silica (ODS) high-performance liquid chromatography (HPLC) column. The general rate (GR) model was employed to calculate the first absolute moment and the second central moment. Three important coefficients for moment analysis, which are molecular diffusivity (
), external mass transfer coefficient (
), and intra-particle diffusivity (
), were estimated by the Wilke-Chang equation, Wilson-Geankoplis equation, and comparing van Deemter equation to theoretical plate number equation, respectively. Experiments were conducted by various conditions of flow rates, methanol volume ratio of the mobile phase, and solute concentration. After the moment analysis, results were organized by van Deemter plots. Also van Deemter coefficients were compared each other to effect
on height equivalent to a theoretical plate (HETP,
). The value of intraparticle diffusion (
) was the primary factor which makes for HETP whereas external mass transfer (
) was disregardable factor.
Study of Formation Factor of Biofilm on Aluminum surface and Removal Efficiency of Biofilm by Antimicrobials
Park, SangJun ; Oh, YoungHwan ; Jo, BoYeon ; Lee, JaeShin ; Lee, SangWha ; Jeong, JaeHyun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 730~739
DOI : 10.9713/kcer.2015.53.6.730
108 microorganism types (79 types of fungi and 29 types of bacteria) were isolated from 25 automobiles generating bad odor when the air conditioner was turned on, and 43 types of fungi and 23 types of bacteria were identified. The analysis of condensate generated by the air conditioners in the automobiles indicated pH 6.4~7.1, 12.5~34.2 mg/L carbon source, 0.9~18.6 mg/L nitrogen source, 0.5~27.8 mg/L ion contents, and 0.1~7.7 mg/L mineral contents. The biofilms were formed by the mesophiles under the summer temperature/humidity condition (
, 70% R.H.), and they were regenerated when the environmental factors (nutritional contents and temperature/humidity) were appropriate even after they were artificially removed. Although the antimicrobials removed 99.9% of planktonic cells within 15 minutes, they were not effective in removing biofilm. Up to 1,950 ppmv of ethanol was observed in the automobile treated with the antimicrobials. Although the figure is lower than the acute toxicity level when inhaled by humans, the health safety of the chemical substances used in the antimicrobials needs to be reviewed.
Comparison of Pectin Hydrogel Collection Methods in Microfluidic Device
Kim, Chaeyeon ; Park, Ki-Su ; Kang, Sung-Min ; Kim, Jongmin ; Song, YoungShin ; Lee, Chang-Soo ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 740~745
DOI : 10.9713/kcer.2015.53.6.740
This study investigated the effect of different collection methods on physical properties of pectin hydrogels in microfluidic synthetic approach. The pectin hydrogels were simply produced by the incorporation of calcium ions dissolved in continuous mineral oil. Then, different collection methods, pipetting, tubing, and settling, for harvesting pectin hydrogels were applied. The settling method showed most uniform and monodispersed hydrogels. In the case of settling, a coefficient of variation was 3.46 which was lower than pipetting method (18.60) and tubing method (14.76). Under the settling method, we could control the size of hydrogels, ranging from
, by simple manipulation of the viscosity of pectin and volumetric flow rate of dispersed and continuous phase. Finally, according to the characteristics of simple encapsulation of biological materials, we envision that the pectin hydrogels can be applied to drug delivery, food, and biocompatible materials.
Kinetic Study of Coal/Biomass Blended Char-CO
Gasification Reaction at Various temperature
Kim, Jung Su ; Kim, Sang Kyum ; Cho, Jong Hoon ; Lee, Si Hoon ; Rhee, Young Woo ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 746~754
DOI : 10.9713/kcer.2015.53.6.746
In this study, we investigated the effects of the temperature on the coal/biomass
gasification reaction under isothermal conditions of
using the lignite(Indonesia Eco coal) with biomass (korea cypress). Ni catalysts were impregnated on the coal by the ion-exchange method. Four kinetic models which are shrinking core model (SCM), volumetric reaction model (VRM), random pore model (RPM) and modified volumetric reaction model (MVRM) for gas-solid reaction were applied to the experimental data against the measured kinetic data. The Activation energy of Ni-coal/biomass, non-catalyst coal/biomass
gasification was calculated from the Arrhenius equation.
A Study of the Temperature Dependency for Photocatalytic VOC Degradation Chamber Test Under UVLED Irradiations
Moon, Jiyeon ; Lee, Kyusang ; Kim, Seonmin ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 755~761
DOI : 10.9713/kcer.2015.53.6.755
Photocatalytic VOCs removal test in gas phase is generally performed by placing the light source on the outside due to maintaining a constant temperature inside the test chamber. The distance between light source and photocatalysts is importantin the VOC degradation test since the intensity of light is rapidly decreased as the distance farther. Especially, for the choice of light source as UVLED, this issue is more critical because UVLED light source emits lots of heat and it is hard to measure the exact concentration of VOCs due to changed temperature in the test chamber. In this study, we modified VOC removal test chamber base on the protocol of air cleaner test and evaluated the efficiency of photocatalystunder UVLED irradiation. Photocatalystsof two different samples (commercial
and the synthesized vanadium doped
) weretested for the p-xylene degradation in the closed chamber system and compared with each other in order to exclude any experimental uncertainties. During the VOC removal test, VOC concentrations were monitored and corrected at regular time intervals because the temperature in the chamber increases
due tothe heat of UVLED. The results showed that theconversion ratio of p-xylene has 40~43% difference before and after the temperature correction. Based on those results, we conclude that the VOC concentration correction must be required for the VOC removal test in a closed chamber system under UVLED light source and obtained the corrected efficiencies of various photocatlysts.
Preparation of Hard Coating Films with High Refractive Index from Titania Nanoparticles
Kim, Nam Woo ; Ahn, Chi Yong ; Song, Ki Chang ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 762~769
DOI : 10.9713/kcer.2015.53.6.762
The titania (
) nanoparticles with a diameter 2?3 nm were synthesized by controlling hydrolysis of titanium tetraisopropoxide (TTIP) in acid solution. Organic-inorganic hybrid coating solutions were prepared by reacting the titania nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at
after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films showed high optical transparency of 90% in the visible range and exhibited a pencil hardness of 2H. Also, the refractive index at 633 nm wavelength of coating films enhanced from 1.502 to 1.584 as the weight content of titania nanoparticles in the coating solutions increased from 4% to 25%.
Thermodynamic and Isothermal Studies of Congo RedAdsorption onto Modified Bentonite
Basava Rao., V. V. ; Mohan Rao., T ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 770~775
DOI : 10.9713/kcer.2015.53.6.770
Adsorption of Congo Red (CR) from dye-containing effluents using modified bentonite (MB) has been investigated here. Isothermal studies were conducted to ascertain maximum adsorption capacity of the adsorbent. MB exhibited superior adsorption capacity compared to other low-cost adsorbents. Experimental data fitted the Langmuir isotherm better, indicating monolayer coverage of CR on MB. The feasibility of the process was measured in terms of separation factor
. The values of Gibbs free energy, entropy and enthalpy were calculated from the thermodynamics of the process. Adsorption was feasible and spontaneous, being endothermic. Analytical techniques including SEM, EDS, FTIR and XRD were applied to characterize MB and also to provide conclusive proof of the accumulation of CR on to MB.
Preparation of Hard Coating Films with High Refractive Index from TiO
Ahn, Chi Yong ; Kim, Nam Woo ; Song, Ki Chang ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 776~782
DOI : 10.9713/kcer.2015.53.6.776
nanoparticles with an average diameter of 3~5 nm were synthesized by hydrolysis of titanium tetraisopropoxide (TTIP) and tin chloride to depress the photocatalytic activity of
nanoparticles. Organic-inorganic hybrid coating solutions were prepared by reacting the
nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at
after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films from
nanoparticles showed an improved pencil hardness of 3H compared to 2H of the coating films from
nanoparticles. Besides, the refractive index of the coating films from
nanoparticles enhanced from 1.543 to 1.623 at 633 nm as the Sn/Ti molar ratio increased from 0 to 0.5.
Effects of Biomass Gasification by Addition of Steam and Calcined Dolomite in Bubbling Fluidized Beds
Jo, WooJin ; Jeong, SooHwa ; Park, SungJin ; Choi, YoungTai ; Lee, DongHyun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 783~791
DOI : 10.9713/kcer.2015.53.6.783
A fluidized-bed reactor with an inside diameter of 0.1 m and a height of 1.2 m was used to study the effect of steam and catalyst additions to air-blown biomass gasification on the production of producer gas. The equipment consisted of a fluidized bed reactor, a fuel supply system, a cyclone, a condenser, two receivers, steam generator and gas analyzer. Silica sand with a mean particle diameter of
was used as a bed material and calcined dolomite (
), which is effective in tar reduction and producer gas purification, was used as the catalyst. Both of Korea wood pellet (KWP) and a pellet form of EFB (empty fruit bunch) which is the byproduct of Southeast Asia palm oil extraction were examined as biomass feeds. In all the experiments, the feeding rates were 50 g/min for EFB and 38 g/min for KWP, respectively at the reaction temperature of
and an ER (equivalence ratio) of 0.25. The mixing ratio (0~100 wt%) of catalyst was applied to the bed material. Air or an air-steam mixture was used as the injection gas. The SBR (steam to biomass ratio) was 0.3. The composition, tar content, and lower heating value of the generated producer gas were measured. The addition of calcined dolomite decreased tar content in the producer gas with maximum reduction of 67.3 wt%. The addition of calcined dolomite in the air gasification reduced lower heating value of the producer gas. However The addition of calcined dolomite in the air-steam gasification slightly increased its lower heating value.
A Study on Physical Dispersion and Chemical Modification of Graphene
Yim, Eun-Chae ; Kim, Seong-Jun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 792~797
DOI : 10.9713/kcer.2015.53.6.792
Graphene has a wide spectrum on its application field due to various and excellent physical properties. However, it is very difficult to apply that graphene exists as lump or fold condition in general organic solvents. Besides, graphene was difficult to maintain as uniform condition due to chemical inert and distributions with various size and shapes. Therefore, this study was focused to study dispersion and modifying methods of aggregated graphene. The dispersion methods contain as follow: i) physical milling using glass bead, ii) co-treatment of glass bead and ultrasonic waves, iii) dispersion in organic solvents, iv) modifying with dry-ice. Milling using glass bead with size 2.5 mm was effective to be size decrease of 36.4% in comparison with control group. Mixed treatment of glass bead (size 2.5 mm) and ultrasonic waves (225W, 10 min) showed relative size decrease of 76%, suggesting that the size decrease depends on the size of glass bead, intensity of ultrasonic waves and treatment time. Solvents of Ethyl acetate (EA) and Isoprophyl alcohol (IPA) were used in order to improve dispersion by modifying surface of graphene. IPA of them showed a favorable dispersion with more -CO functional groups in the FT-IR analysis. On the other hand, the oxygen content of graphene surface modified by dry-ice was highly increased from 0.8 to 4.9%. From the results, it was decided that the favorable dispersion state for a long time was obtained under the condition of -CO functional group increase in IPA solvent.
The Synthesis of CdTe Nanowires Based on Stabilizers with Low Concentrations
Kim, Ki-Sub ; Kang, Jeong Won ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 798~801
DOI : 10.9713/kcer.2015.53.6.798
Nanomaterials (NMs) based on cadmium telluride (CdTe) are the theme of numerous research areas due to their unique chemical and physical properties. NM synthesis via a size-controlled procedure has become an intriguing research topic because NMs exhibit novel optical and physical properties depending on their size and shape. In this study, we prepared CdTe nanowires (NWs) via self-assembly from individual Nanoparticles (NPs). Thioglycolic acid (TGA)-to-Cd ion ratio of 1.3 was used instead of the traditional value of 2.4 and the reduced amount of stabilizer resulted in reorganization from individual NPs into NWs consisting of multi-layers of individual NPs. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were performed to characterize NWs. The produced nanowires were straight and long in shape and their length ranged from 500 nm to tens of micrometers.
A Study on Performance Improvement of Glucose Sensor Adopting a Catalyst Using New Cross Liker
Chung, Yongjin ; Kwon, Yongchai ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 802~807
DOI : 10.9713/kcer.2015.53.6.802
In this study, we synthesized a new biocatalyst consisting of glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT) with addition of terephthalaldehyde (TPA) (TPA/GOx/PEI/CNT) for fabrication of glucose sensor that shows improved sensing ability and stability compared with that using other biocatalysts. Main bonding of the new TPA/GOx/PEI/CNT catalyst is formed by Aldol condensation reaction of functional end groups between GOx/PEI and TPA. Such formed bonding structure promotes oxidation reaction of glucose. Catalytic activity of TPA/GOx/PEI/CNT is evaluated quantitatively by electrochemical measurements. As a result of that, large sensitivity value of
is gained. Regarding biosensor stability of TPA/GOx/PEI/CNT catalyst, covalent bonding formed between GOx/PEI and TPA prevents GOx molecules from becoming leaching-out and contributes improvement in biosensor stability. With estimation of the biosensor stability, it is found that the TPA/GOx/PEI/CNT catalyst keeps 94.6% of its initial activity even after three weeks.
Removal of Aqueous Boron by Using Complexation of Boric Acid with Polyols: A Raman Spectroscopic Study
Eom, Ki Heon ; Jeong, Hui Cheol ; An, Hye Young ; Lim, Jun-Heok ; Lee, Jea-Keun ; Won, Yong Sun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 808~813
DOI : 10.9713/kcer.2015.53.6.808
Boron is difficult to be removed from seawater by simple RO (reverse osmosis) membrane process, because the size of boric acid (
), the major form of aqueous boron, is as small as the nominal pore size of RO membrane. Thus, the complexation of boric acid with polyols was suggested as an alternative way to increase the size of aqueous boron compounds and the complexation behavior was investigated with Raman spectroscopy. As a reference, the Raman peak for symmetric B-O stretching vibrational mode both in boric acid and borate ion (
) was selected. A Raman peak shift (
) was observed to confirm that boric acid in water is converted to borate ion as the pH increases, which is also correctly predicted by frequency calculation. Meanwhile, the Raman peak of borate ion (
) did not appear as the pH increased when polyols were applied into aqueous solution of boric acid, suggesting that the boric acid forms complexing compounds by combining with polyols.
Electrochemical Ionic Mass Transfer Correlation in Fluid-Saturated Porous Layer
Cho, Eun Su ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 814~817
DOI : 10.9713/kcer.2015.53.6.814
A new ionic mass transfer correlation is derived for the fluid-saturated, horizontal porous layer. Darcy-Forchheimer model is used to explain characteristics of fluid motion. Based on the microscales of turbulence a backbone mass transfer relation is derived as a function of the Darcy-Rayleigh number,
and the porous medium Schmidt number,
. For the Darcy's limit of
, the Sherwood number, Sh is a function of
only. However, for the region of high
, Sh can be related with
. Based on the present backbone equation and the electrochemical mass transfer experiments which are electro plating or electroless plating, the new ionic mass transfer correlation is suggested in the porous media.
Analysis on Thermal Effects of Process Channel Geometry for Microchannel Fischer-Tropsch Reactor Using Computational Fluid Dynamics
Lee, Yongkyu ; Jung, Ikhwan ; Na, Jonggeol ; Park, Seongho ; Kshetrimayum, Krishnadash S. ; Han, Chonghun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 818~823
DOI : 10.9713/kcer.2015.53.6.818
In this study, FT reaction in a microchannel was simulated using computational fluid dynamics(CFD), and sensitivity analyses conducted to see effects of channel geometry variables, namely, process channel width, height, gap between process channel and cooling channel, and gap between process channels on the channel temperature profile. Microchannel reactor considered in the study is composed of five reaction channels with height and width ranging from 0.5 mm to 5.0 mm. Cooling surfaces is assumed to be in isothermal condition to account for the heat exchange between the surface and process channels. A gas mixture of
molar ratio = 2) is used as a reactant and operating conditions are the following: GHSV(gas hourly space velocity) =
, pressure = 20 bar, and temperature = 483 K. From the simulation study, it was confirmed that heat removal in an FT microchannel reactor is affected channel geometry variables. Of the channel geometry variables considered, channel height and width have significant effect on the channel temperature profile. However, gap between cooling surface and process channel, and gap between process channels have little effect. Maximum temperature in the reaction channel was found to be proportional to channel height, and not affected by the width over a particular channel width size. Therefore, microchannels with smaller channel height(about less than 2 mm) and bigger channel width (about more than 4 mm), can be attractive design for better heat removal and higher production.
Oxidative Dehydrogenation of 1-butene over BiFe
Catalyst: Effect of Phosphorous Precursors
Park, Jung-Hyun ; Youn, Hyun Ki ; Shin, Chae-Ho ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 824~830
DOI : 10.9713/kcer.2015.53.6.824
The influence of phosphorous precursors,
, on the catalytic performance of the
catalysts in the oxidative dehydrogenation of 1-butene to 1,3-butadiene was studied. The catalysts were characterized by XRD,
-sorption, ICP, SEM and TPRO analyses. It was not observed big difference on the physical properties of catalysts in accordance with used different phosphorous precursors, however, the catalytic performance was largely depended on the nature of the phosphorous precursors. Of various precursors, the
oxide catalyst, which was prepared from a phosphoric acid precursor, showed the best catalytic performance. Conversion and yield to butadiene of the catalyst showed 79.5% and 67.7%, respectively, after 14 h on stream. The cation of phosphorous precursors was speculated to affect the lattice structure of the catalysts during catalyst preparation and this difference was influenced on the re-oxidation ability of the catalysts. Based on the results of TPRO, it was proposed that the catalytic performance could be correlated with re-oxidation ability of the catalysts.
Influence of Zeta Potential on Fractional Precipitation of (+)-Dihydromyricetin
Ha, Geon-Soo ; Kim, Jin-Hyun ;
Korean Chemical Engineering Research, volume 53, issue 6, 2015, Pages 831~835
DOI : 10.9713/kcer.2015.53.6.831
This study evaluated the influence of the zeta potential of silica-alumina on the behavior in terms of purity, yield, and precipitate shape and size of fractional precipitation in the fractional precipitation process for the purification of (+)-dihydromyricetin. The optimal silica-alumina amount (surface area per working volume of reacting solution) for zeta potential control was
. As the zeta potential value of silica-alumina increased, (+)-dihydromyricetin yield and precipitate size were increased. The use of silica with the highest value of the zeta potential (+4.99 mV) as a zeta potential-controlling material increased the (+)-dihydromyricetin yield by 2-fold compared with that of the use of alumina with the lowest value of the zeta potential (-19.00 mV). In addition, the (+)-dihydromyricetin yield and precipitate size was inversely correlated with the absolute value of the zeta potential. On the other hand, the purity of (+)-dihydromyricetin had almost no effect on changes in the zeta potential of silica-alumina.