Korean Journal of Chemical Engineering (v.25, #3)

This paper reports a study on the ability of the computational fluid dynamics (CFD) modeling for analyzing the fluid flow hydrodynamics and absorption in a packed bed column. The water absorption by silica gel absorbents in an experimental packed bed was investigated, and the absorption performance of two different sizes of absorbent was studied. A series of experiments were carried out for five setups which are different in the weight ratio of the employed big to small absorbents. The CFD modeling was carried out for all five experimental setups. The predicted results show that by more replacing of the big absorbents with the small ones the water absorption increased. On the other hand, a greater pressure drop was observed as more small absorbents were used. The predicted absorption rates were compared with the measured values and on average a consistency within 11.6% was observed.
Keywords: Absorption; Computational Fluid Dynamics; Modeling; Packed Bed; Column

Synthesis of nonsharp distillation sequences via genetic programming by Xiao-Hong Wang; Yang-Dong Hu; Yu-Gang Li (402-408).
This paper addresses the application of Genetic Programming (GP) to the synthesis of multicomponent product nonsharp distillation sequences. Combined with the domain knowledge of chemical engineering, some evolutionary factors are improved, and a set of special encoding method and solving strategy is proposed to deal with this kind of problem. The system structural variable is optimized by GP and the continuous variable is optimized by the simulated annealing algorithm simultaneously. Because GP has an automatic searching function, the optimal solution can be found including distillation, splitting, blending and bypassing operations automatically without any superstructures of nonsharp distillation sequences. Three illustrative examples are presented to demonstrate the effective computational strategies.
Keywords: Non-sharp Distillation Sequences; Genetic Programming; Synthesis

To achieve safe operation and to improve economics it is imperative to monitor and analyze demand and supply of utilities and to meet utility needs in time. The main objective of motor/turbine processes is to manipulate optimal balances on steam and electricity in utility plants. The optimal operation of motor/turbine processes is by far the most important to improve economics in the utility plant. In order to analyze motor/turbine processes, steady state models for steam generation equipment and steam distribution devices as well as turbine generators are developed and analyzed in this work. In addition, heuristics concerning various operational situations are incorporated in the models. The motor/turbine optimal operation system is based on utility models and operational knowledgebase, and provides optimal operating conditions when the amount of steam demand from various steam headers is changed frequently. The optimal operation system also produces optimal selection of driving devices for utility pumps to reduce operating cost.
Keywords: Utility Plant; Motor/Turbine Process; Optimization; Steam Header; Knowledgebase

Adiabatic runaway studies for methyl ethyl ketone peroxide with inorganic acids by vent sizing package 2 by Jiann-Rong Chen; Jo-Ming Tseng; Yan-Fu Lin; Shu-Yu S. Wang; Chi-Min Shu (419-422).
Methyl ethyl ketone peroxide (MEKPO) is an unstable material that is classified as an explosive substance. We evaluated MEKPO 10 mass% under mixing with three inorganic acids (6 N HNO3, 6 N H3PO4, and 6 N H2SO4) by adiabatic system of vent sizing package 2 (VSP2). Results from evaluation and testing indicated that these three inorganic acids could increase the degree of hazard while combined with pure MEKPO. Therefore, information on the hazards and phenomena of runaway reaction should be provided in order to lessen the degree of hazard.
Keywords: Methyl Ethyl Ketone Peroxide; Inorganic Acids; Vent Sizing Package 2 (VSP2); Runaway Reaction; Degree of Hazard

Effects of structural variations of the diimine ligand on catalyst activities for vinyl polymerization of norbornene (NB) have been investigated by a series of Ni(II) α-diimine catalysts of the general formula: [{ArN=C(Ac)-C(Ac)=NAr}]NiBr2 (Ac=acenaphthyl) (Cat(H), Ar=C6H5; Cat(2,6-Me), Ar=2,6-C6H3Me2; Cat(2,6-Et), Ar=2,6-C6H3Et2; Cat(2,6- i Pr), Ar=2,6-C6H3 i-Pr2; Cat(2,3-Me), Ar=2,3-C6H3Me2; Cat(2,4-Me), Ar=2,4-C6H3Me2; Cat(2,5-Me), Ar=2,5-C6H3Me2; Cat(3,5-Me), Ar=3,5-C6H3Me2; Cat(2,4,6-Me), Ar=2,4,6-C6H2Me3). In situ reactions with methylaluminoxane generated the active catalysts, and they showed good activity towards NB polymerizations. As indicated by relatively higher activities of Cat(H) and Cat(3,5-Me), it can be generalized that catalysts having 2,6-substituents are less active due to steric interaction between monomer and substituents. In addition, electron donating methyl groups at 2-, 4-or 6-position on the N-aryl have a con effect and that at 3,5-position has a pro effect.
Keywords: Catalysis; Diimine Ligands; Late Transition Metal; Microstructure; Norbornene; Vinyl Polymerization

Recovery of useful chemicals from oil palm shell-derived oil using zirconia supporting iron oxide catalysts by Duangkamol Na-Ranong; Ratanaporn Yuangsawad; Teruoki Tago; Takao Masuda (426-430).
The possibility for recovering methanol, acetic acid and phenol from oil palm shell-derived oil was investigated. Thermal cracking mainly produced a solid residue and was not a suitable method for recovering these three target chemicals. When zirconia supporting iron based catalyst (Zr/FeOx, Zr-FeOx or Zr-Al-FeOx) was applied, the “others”—unidentified hydrocarbons—were satisfactorily removed without formation of a solid residue while these target compounds were considerably stable over these catalysts. Zr-Al-FeOx showed the highest activity for oxidation of the oil to CO2. Effect of operating parameters (steam to oil ratio, temperature and time factor) on its performance was further investigated. In order to gain insight into the reaction path, the reaction using model compounds (methanol, acetic acid, acetone, ethyl acetate and phenol) was performed.
Keywords: Biomass Utilization; Renewable Chemicals; Catalytic Cracking; Iron Oxide Catalyst; Oil Palm Shell

Preparation of Pt-Co catalysts on mesoporous carbon and effect of alloying on catalytic activity in oxygen electro-reduction by Ji Bong Joo; You Jung Kim; Wooyoung Kim; Nam Dong Kim; Pil Kim; Younghun Kim; Youn-Woo Lee; Jongheop Yi (431-436).
Mesoporous carbon (MC)-supported PtCo catalysts were prepared by a sodium borohydride (NaBH4) reduction method. To increase the alloy degree of PtCo catalyst, the heat treatment was carried out at various temperatures (300–700°C). The heat-treated PtCo catalysts (PtCo/MC-x) had the higher degrees of Pt-Co alloy than that of as-synthesized PtCo catalyst (PtCo/MC). MC supported-PtCo catalyst (PtCo/MC-500) that was treated at 500°C, had the highest activity and lowest overpotential in oxygen electro-reduction (ORR) among the prepared PtCo catalysts. The high alloy degree and favorable chemical states of PtCo/MC-500 are believed to be responsible for the superior activity in oxygen electroreduction compared to the other PtCo catalysts.
Keywords: Mesoporous Carbon; Electrocatalyst; PtCo; Oxygen Reduction; Fuel Cell

High efficiency ester condensation using hydrophobic zeolite membranes by Tomoya Inoue; Yuta Nemoto; Takako Nagase; Yasuhisa Hasegawa; Yoshimichi Kiyozumi; Koichi Sato; Masateru Nishioka; Satoshi Hamakawa; Toshikazu Nishide; Fujio Mizukami (437-442).
We successfully developed zeolite membranes with hydrophilic character, by choosing appropriate zeolites in terms of hydrophilicity and high acid tolerance. We evaluated thus developed membranes by their pervaporation (PV) performance, dehydration from acidic organic solvent. The zeolite membranes we developed, based on merlinoite (MER), chabazite (CHA) or phillipsite (PHI), are shown to exhibit stable dehydration performance, respectively. We successfully applied the membranes to the selective removal of water in an ester condensation reaction starting from a stoichiometric mixture of a carboxylic acid and an alcohol. The availability of pervaporation-assisted ester condensation reaction was validated by various kinds of combinations of carboxylic acid and alcohols, which implies the general availability of pervaporation-assisted process intensification by zeolite membranes.
Keywords: Zeolite Membranes; Pervaporation; Dehydration; Ester Condensation

Electrochemical deposition of Pt nanoparticles on CNTs for fuel cell electrode by Heeyeon Kim; Nam Jo Jeong; Seung Jae Lee; Kwang Sup Song (443-445).
In order to increase the performance of fuel cell electrode, carbon nanotubes (CNTs) were used as support instead of conventional carbon black, and the Pt catalyst was synthesized by using electrochemical deposition (ECD) method which has recently been adopted as a synthetic tool of metal nanoparticles. CNTs used in this paper were grown directly on carbon paper by chemical vapor deposition (CVD) of acetylene. Highly dispersed and nano-sized Pt particles were electrochemically deposited on CNTs surface, which would simplify the manufacturing process of membrane-electrode-assembly (MEA). Pt particles on CNTs were investigated by SEM and TEM. The particle size of Pt is less than 2 nm, which is relatively small compared to that of conventional wet impregnated catalyst (2–8 nm). CO chemisorption results show that the amounts of catalytic sites are about three times larger in Pt/CNT prepared by ECD than those in conventional wet-impregnated one. The mass activity of the former catalyst for oxygen reduction is more than three times higher compared to that of the latter one.
Keywords: Carbon Nanotubes (CNTs); Pt; Fuel Cell; Electrochemical Deposition (ECD); Chemical Vapor Deposition (CVD)

Application of physical vapor deposition process to modify activated carbon fibers for ozone reduction by Yu-Chih Lin; Chung-Liang Chang; Tser-Sheng Lin; Hsunling Bai; Ming-Gu Yan; Fu-Hsiang Ko; Chia-Tien Wu; Cheng-Hsiung Huang (446-450).
This study utilized the activated carbon fiber (ACF) modified with metal catalyst via physical vapor deposition (PVD) process (ACF/PVD) to diminish ozone. Furthermore, the ozone removal efficiency of ACF/PVD was compared with that of original ACF and ACF modified with metal catalyst via impregnation process (ACF/impregnation). In addition to the kinds of coated metal and the inlet ozone concentrations, the effects of the coating thickness and the reaction temperature on ACF/PVD for ozone removal were also examined. The results indicate that the ozone removal efficiency of ACF/PVD is better than that of original ACF and ACF/impregnation. The ozone removal efficiency of different metal-coated ACF/PVD in the superior order is gold (Au), and manganese (Mn). The increase of Au-coated thickness (3 nm to 80 nm) on ACF/PVD will enhance the ozone removal. However, when the Mn-coated thickness on ACF/PVD is larger than 15 nm, the ozone removal efficiency displays a declining trend. Furthermore, a higher reaction temperature will result in a better ozone removal of ACF/PVD and the original ACF.
Keywords: Ozone; Activated Carbon; Physical Vapor Deposition; Adsorption

Kinetic of CO2 absorption and carbamate formation in aqueous solutions of diethanolamine by Abdelbaki Benamor; Brahim Si Ali; Mohamed Kheireddine Aroua (451-460).
The absorption rates of CO2 into aqueous solutions of Diethanolamine (DEA) with varying concentrations from 0.2 to 4M and temperature range from 293 to 323 K were measured by using a laboratory stirred reactor. The CO2 partial pressure was varied in a range that the reaction would occur in pseudo first order regime. Experimental data were analyzed and the kinetic parameters associated with the reaction were determined. The activation energy for the deprotonation of the intermediate zwitterion was estimated at about 11.4 kcal/mol. The contribution of carbamate formation to the overall absorbed CO2 was experimentally evaluated and found to be of the order of 100%.
Keywords: Diethanolamine; Carbon Dioxide; Carbamate; Absorption Kinetics

Cellular automata modeling of continuous stirred tank reactors by Jaime Enrique Pérez-Terrazas; Vrani Ibarra-Junquera; Haret Codratian Rosu (461-465).
The classical dynamical systems model of continuous stirred tank reactors (CSTR) in which a first order chemical reaction takes place is reformulated in terms of the stochastic cellular automata procedure developed in the works of Seyborg [2] and Neuforth [3], which is extended by including the feed flow of chemical reactants. We show that this cellular automata model is able to simulate the dilution rate and the mixing process in the CSTR, as well as the details of the heat removal due to the jacket. The cellular automata approach is expected to be of considerable applicability at any industrial scale and especially for any type of microchemical system.
Keywords: Stochastic Cellular Automata; Continuous Stirred Tank Reactors; Probabilistic Minimal Noise Rule; Kinetic Rates

The effect of pressure on the direct synthesis of dimethyl ether (DME) from syngas over metal (Cu, Zn) pillared ilerites and metal (Cu, Zn) impregnated metal-pillared ilerites was explored. The prepared catalysts were characterized by XRD, BET, ICP-AES, SEM and FT-IR. The direct DME synthesis reaction was carried out in a differential fixed bed reactor with the prepared catalysts at various pressures (10, 20, 30 bar), 250°C and H2/CO ratio of 2. The Cu/Zn-pillared ilerite catalyst showed the highest catalytic activity among the prepared catalysts at 20 bar, in which CO conversion was about 62% and DME selectivity was about 89%. CO conversion increased with pressure, and DME selectivity increased with pressure in the range of 10–20 bar, and above the pressure slightly decreased with pressure. The optimum pressure for this reaction was 20 bar.
Keywords: Metal-pillared Ilerite; Dimethyl Ether (DME); Direct DME Synthesis; Syngas

Catalytic performance of pyridinium salt ionic liquid in the synthesis of cyclic carbonate from carbon dioxide and butyl glycidyl ether by Hye-Young Ju; Ji-Yeon Ahn; Mamparambath-Dharman Manju; Kyung-Hoon Kim; Dae-Won Park (471-473).
The catalytic performance of pyridinium salt ionic liquids in the reaction of butyl glycidyl ether and carbon dioxide was investigated in this study. The catalytic activity was studied in a batch reactor with different 1-alkylpyridinium salt ionic liquids at 60–140°C. The conversion of butyl glycidyl ether was affected by the structure of the ionic liquid; the one with the cation of bulkier alkyl chain length showed better reactivity. The effect of carbon dioxide pressure, reaction temperature and zinc bromide co-catalyst on this reaction was also discussed.
Keywords: Pyridinium Salt; Ionic Liquid; Butyl Glycidyl Ether; Carbon Dioxide

Modification of soybean oil for intermediates by epoxidation, alcoholysis and amidation by Kyu-Wan Lee; Cheng Hailan; Jin Yinhua; Young-Wun Kim; Keun-Woo Chung (474-482).
Vegetable oils are a major source of many base chemicals. Unfortunately, most vegetable oils exhibit lower thermal and oxidation stability because of double bonds and even worse low-temperature behaviors. These physical and chemical properties can be improved by various chemical modifications. The catalytic hydrogenation of soybean oil (SBO) over 25% Ni/SiO2 and 5% Pt/C is one of them, and the epoxidation of soybean oil and reduced soybean oil (RSBO) was carried out by using 30% of hydrogen peroxide and acetic acid in the presence of conc. sulfuric acid, and/or acidic Amberlyst 15 resin catalyst. Various alcohols and amines were added to the epoxidized soybean oil (ESBO) in the hope of improving lubricant properties. The reaction products were carefully analyzed by means of 1H-NMR, FT-IR spectroscopies and GC-MS spectrometry. This paper covers the epoxidation of virgin and RSBOs, alcoholysis and amidation of ESBO and SBO. Finally, the structures of cross linked products synthesized from ESBO and SBO with 1,6-hexamethylendiamine were proposed.
Keywords: Epoxidation; Soybean Oil; Alcoholysis; Amidation; Cross Linking

A modeling study of the impact of natural and urban forest on ambient ozone by Kwang Jin Kim; Yoo Jung Kim; Young-Il Ma; Jo-Chun Kim; Young Sunwoo (483-492).
Impact estimation of biogenic VOCs (Volatile Organic Compounds) to control ambient ozone is needed. For this, BVOCs emission is calculated by using BEIS, and the impact of ozone is estimated with UAM in the research area, Daegu metropolitan city. It is estimated that 59 ppb and 50 ppb of ozone concentration is caused by BVOCs emissions and anthropogenic emissions, respectively. As for tree type, deciduous trees have greater influence than conifers on the daily maximum 1-hr ozone concentration though the former’s distribution area is smaller than the latter’s. In addition, variation of ozone concentration by BVOCs emission is more sensitive in city areas compared to rural areas. If we change the landscape from woody plants (urban trees) to lower ozone-forming potential (OFP) species, it should lead to a reduction in grids that exceed the national ambient ozone standard.
Keywords: Biogenic Volatile Organic Compound; Isoprene; Monoterpene; BEIS; Ozone

Dehalogenation of toxic organic compounds has been intensively studied during the last decade by using zero-valent iron (ZVI). However, the reactivity of iron is compound specific and very low reactivities were reported for aromatic compounds including chlorophenols. In this study, hydrodechlorination of 2,4,6-trichlorophenol (2,4,6-TCP) was conducted in a batch system by using ZVI and catalyzed iron. No degradation was observed with ZVI over the 40 days experiments. Catalyzed ZVIs removed 2,4,6-TCP and palladium-coated iron (Pd/Fe) and nickel-coated iron (Ni/Fe) showed relatively enhanced reactivity while copper-coated iron (Cu/Fe) and platinum-coated iron (Pt/Fe) showed lower reactivities. The surface area normalized kinetic constants (k SA ) of Pd/Fe, Ni/Fe, Cu/Fe, Pt/Fe are 2.54×10−4, 1.01 × 10−4, 2.24×10−5, 2.56×10−5 L m−2 h−1, respectively. The identification of less chlorinated phenols and phenol confirmed that the removal is dechlorination. Pd/Fe system exerts relatively low pH compared with the ZVI system, and the low pH is favorable for the dechlorination. The reactivity enhancement of catalyzed iron was discussed in terms of catalytic effects and the corrosion potential by the bimetal coupling. Variable Pd content on the Pd/Fe was tested, and the degradation rate of 2,4,6-TCP increased in proportion to the increase of Pd content.
Keywords: 2,4,6-Trichlorophenol (2,4,6-TCP); Zero-valent Iron (ZVI); Catalyzed Iron; Hydrodechlorination

Purification and removal of Ascaris and Fasciola hepatica eggs from drinking water using roughing filters by Jafar Nouri; Amir Hossein Mahvi; Reza Saeedi; Kavoos Dindarloo; Mohammad Rafiee; Sina Dobaradaran (501-504).
The performance of a horizontal roughing filter (HRF) and a downflow roughing filter (DRF) in the removal of Ascaris and Fasciola hepatica eggs was investigated. The experiments were performed at three filtration rates of 0.5, 1.0 and 1.5 m/h and different influent concentrations of Ascaris and Fasciola hepatica eggs. Alteration of the filtration rate in the range of 0.5–1.5 m/h did not have significant influence on the effectiveness of the roughing filters. The HRF had higher efficiency in the removal of both Fasciola hepatica and Ascaris eggs in comparison with the DRF, so that the average efficiencies of the HRF for the removal of Fasciola hepatica and Ascaris eggs at filtration rate of 1.0 m/h were determined to be 89.0 and 57.3%, respectively, whereas the same values of the DRF were 77.2 and 52.5%, respectively. The straining was confirmed to be the main mechanism of helminth eggs removal by the roughing filters, because Fasciola hepatica eggs with larger size were removed more effectively than Ascaris eggs. The results of this study indicate that the roughing filters, especially the HRF, had promising performance in the removal of helminth eggs and could be used for water and secondary effluent treatment.
Keywords: Water; Ascaris ; Fasciola hepatica ; HRF; DRF

This study evaluated the beneficial effects on the coagulation process of combining coagulants with Fe and Al in the removal of turbidity and DOC (dissolved organic carbon), and proposed conditions for proper operation of a coagulation process. In addition, the floc characteristics and sludge dewater ability were evaluated. Blended coagulants were more effective than single coagulants at lower concentrations in water purification. The optimal blended ratio for the removal of DOC was 1.45 mM as Al/mM as Fe. Also, blended coagulants were less affected than single coagulants by pH, temperature, and rapid mixing intensity. Based on the results of the change in the apparent molecular weight distribution (AMWD) of DOC in raw and treated water by coagulation, low molecular weight organic matters were removed by 40.7% for the blended coagulant (1.45 mM as Al/mM as Fe). Blended coagulants formed larger flocs than single coagulants did. At pH 6.0, floc strength and sludge dewaterablity were both improved.
Keywords: DOC; Turbidity; Coagulation; Water Treatment; Floc; Blended Coagulant

Enhanced β-carotene production by Rhodotorula glutinis using high hydrostatic pressure by Sui-Lou Wang; Jun-She Sun; Bei-Zhong Han; Xiao-Zong Wu (513-516).
High hydrostatic pressure (HHP) technology was used for improving the ability of β-carotene biosynthesis of Rhodotorula glutinis R68. After the treatments of five repeated cycles at 300 MPa for 15 min, the barotolerant mutant PR68 was obtained. After 72 h of culture, the biomass of mutant PR68 was 21.6 g/L, decreased by 8.5% compared to the parent strain R68, but its β-carotene production reached 19.4 mg/L, increased by 52.8% compared to the parent strain R68. The result of restriction fragment length polymorphism analysis suggested that mutant strain PR68 was likely to change in nucleic acid level, and thus enhanced β-carotene production in this strain was a result of gene mutation induced by HHP treatment. HHP technology seems a promising approach for improving industrial microbes.
Keywords: β-Carotene Production; High Hydrostatic Pressure; Rhodotorula glutinis ; Mutation

The effect of ultrasound in combination with thermal treatment on the germinated barley’s alpha-amylase activity by Maryam Yaldagard; Seyed. Ali. Mortazavi; Farideh. Tabatabaie (517-523).
The effects of ultrasound as emerging technology along with thermal treatment were investigated on the activity of barley’s alpha-amylase after germination. All experiments were carried out at 20 kHz on an ultrasonic generator by considering the three effective factors, temperature (30, 50 and 70°C) and ultrasonic intensities (20, 60 and 100% setting from total power of device (460 W)) in different time intervals (5, 10 and 15 min). For determining the effects of these parameters, the enzymatic activity was assayed by measuring the reducing sugars released as a result of the alpha-amylase action on soluble starch using 3,5-dinitrosalicylate regent (DNS). The results of these assays were analyzed by Qualitek4 software by using the Taguchi statistical method to evaluate the factor’s effects on the enzyme activity. Consequently, the results of assays showed that the activity of this enzyme from germinated barley was reduced after thermosonication by comparing to the blank.
Keywords: Ultrasound; Alpha-amylase Activity; Germinated Barley; Taguchi Statistical Method

Percolation bacterial leaching of low-grade chalcopyrite using acidophilic microorganisms by Karanam Srinivasa Rao; Amrita Mishra; Devbrata Pradhan; Gautam Roy Chaudhury; Birendra Kumar Mohapatra; Trupti Das; Lala Bihari Sukla; Barada Kanta Mishra (524-530).
Bioleaching studies were carried out in percolation columns using low-grade copper containing rock (granite). The lixiviant consisted of acidified ferric sulfate containing acidophilic microorganisms. The iron oxidizing strain was isolated from Malanjkhand mine water and after adaptation the iron oxidation observed to be 500 mg/L/h. Leaching parameters studied were lixiviant flow rate, particle size and bed height. It was observed that leaching efficiency increased with decrease of particle size and lixiviant flow rate. The precipitation of iron during leaching observed to be low as pH was maintained at 2. Based on the leaching kinetics, a unified rate equation was developed and shown as r(d p )−0.61 (F)−0.76 (H b )0.97.
Keywords: Bacterial Leaching; Columns; Lixiviant; Thiobacillus ferrooxidans ; Particle Size

Bio-dissolution of copper from Khetri lagoon material by adapted strain of Acidithiobacillus ferrooxidans by Mousumi Mishra; Sradhanjali Singh; Trupti Das; Rabi Narayana Kar; Karanam Srinivasa Rao; Lala Bihari Sukla; Barada Kanta Mishra (531-534).
Bioleaching involves the use of iron and sulfur oxidizing microorganisms to catalyze the dissolution of valuable metals. In this investigation, lagoon material contains 0.39% Cu, in which the major copper bearing mineral is chalcopyrite associated with other minerals present as minor phase. Leaching experiments were carried out using an adapted strain of Acidithiobacillus ferrooxidans with various parameters such as presence/absence of iron, pH, pulp density and temperature. Base of the medium was 9 K (without ferrous) Bio-dissolution of copper was found to be maximum, i.e., 80.9% with 9 K+ (with ferrous) at pH-2.0, 10% pulp-density and 35 °C within an incubation period of 30 days.
Keywords: Acidithiobacillus ferrooxidans ; Khetri Lagoon Material; Bioleaching; Copper

Removal of volatile fatty acids in anaerobic digestion of organic wastes can accelerate eventual decomposition of organic wastes to CO2 and H2O using a recovery of electric energy by a microbial fuel cell. The fuel cell anode chamber was a 10 cm (I.D.)×20 cm long cylindrical Plexiglass having an ion ceramic cylinder separator (I.D.10 mm, O.D.12 mm, 0.3 μm average pore size). The aluminum foil cathode (12 cm2 surface area) was located inside the ceramic cylinder. Between the two cylinders, 1 liter of activated carbon particles was packed as anode electrode having a void fraction of 0.4. This fuel cell was connected to a 5 liter bioreactor (working volume 1.5 liter), and the bioreactor was run in batch mode by re-circulating a synthetic wastewater of 5 g/L glucose. Maximum TVFA (total volatile fatty acids) and SCOD (soluble chemical oxygen demand) removal rate were 3.79 g/L·day, 5.88 g/L·day, respectively. TVFA removal efficiency (92.7%) and SCOD removal efficiency (94.7%) under maximum current density operation were higher than the operation with maximum power density. In acid fermentation, butyric acid concentration was highest because Clostridium butyricum was a dominant microbial communitiy in the inoculum. The microbial cells collected from the anode bio-film samples were affiliated with Bacillus cereus based on the nucleotide sequences of dominant DGGE (denaturing gradient gel electrophoresis) bands.
Keywords: Microbial Fuel Cell; Acidogenesis; Fermentation; Organic Acid; DGGE

Spent sulfidic caustics (SSCs) produced from petrochemical plants contain a high concentration of hydrogen sulfide and alkalinity, and some organic matter. Most of the SSCs are incinerated with the auxiliary fuel causing secondary pollution problems. The reuse of this waste is becoming increasingly important in terms of economical and environmental viewpoints. To denitrify wastewater with a low COD/N ratio, additional carbon sources are required. Therefore, autotrophic denitrification has received increasing attention. In this research, SSCs were injected as electron donors for sulfur-based autotrophic denitrification in a modified Ludzack-Ettinger (MLE) process. According to the variations in the SSCs dosage, the efficiencies of COD, nitrification and TN removal were evaluated. Heterotrophic denitrification by organic matter and autotrophic denitrification by SSCs were also investigated. As a result, adequate injection of SSCs showed stable autotrophic denitrification. To investigate some of the harmful effects of SSCs, fluorescence in situ hybridization (FISH) for nitrifying bacteria and Thiobacillus denitrificans was performed. Ammoniaoxidizing bacteria (AOB) and Nitrospira genus showed a similar pattern. Excessive injection of SSCs made nitrifying bacteria decrease and nitrification failure occur because of the high pH caused by the SSCs. The distribution of T. denitrificans was relatively uniform as SSCs were injected. This result means that T. denitrificans are available at high pH.
Keywords: Autotrophic Denitrification; Spent Sulfidic Caustics; Fluorescence In Situ Hybridization; Thiobacilus denitrificans ; Nitrifying Bacteria

Characterization of a carbon composite electrode for an electrochemical immunosensor by Eun Chan Cho; Byong Ok Jang; Eui Jung Kim; Kee-Kahb Koo (548-552).
A bioactive platform with a carbon composite electrode was developed for rapid detection of Escherichia coli O157:H7. The porous carbon composite electrode was prepared by a sol-gel method with a mixture of graphite powder and tetraethyl orthosilicate/ethanol. Escherichia coli O157:H7 antibodies were physically adsorbed onto the carbon composite electrode. Direct measurements by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4− as a redox probe showed that the immobilization of antibodies onto the carbon composite electrode surface and the binding of Escherichia coli O157:H7 cells with antibodies systematically increased the electron-transfer resistance. Those results suggest that a sol-gel derived graphite composite electrode might be utilized as a label-free electrochemical immunosensor for diagnosis, biochemical research, food industry, and so on.
Keywords: Immunosensor; Carbon Electrode; Sol-gel; E. coli O157:H7; Cyclic Voltammetry; Electrochemical Impedance Spectroscopy

Non-steady state estimation of biodegradability of dyeing wastewater using respirometer by Chiil Kim; Eun Kyung Choe; In-Soung Chang (553-557).
Dyeing wastewater is notorious for its non-readily-biodegradability because it contains various kinds of refractory chemicals. To set up a strategy for controlling the dyeing wastewater discharged into conventional wastewater treatment plants, obtaining bio-kinetic information such as maximum specific growth rate (µ max ) and half saturation constant (K s ) should first be done. To estimate the biodegradability of the dyeing wastewater, bio-kinetic constants of the artificially formulated dyeing wastewater containing 33 different dyes and auxiliaries were determined by using a respirometer. Activated sludge acclimated to the artificial dyeing wastewater was inoculated to the respirometer and the bio-kinetic constants were determined from oxygen uptake data. The µ max was found to 0.06 hr−1, which is 3 to 15 times smaller than that of the typical activated sludge for sewage treatment. The K s was found to 210 mg/L, which was 3.5 to 21 times higher than that of the normal activated sludge.
Keywords: Auxiliaries; Biodegradability; Bio-kinetics; Dyeing Wastewater; Respirometer

The solubility of 4-(3,4-dichlorophenyl)-1-tetralone in eleven alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, 2-butanol, 2-pentanol, 1,2-propanediol, 1,3-propanediol) was measured by using a laser technique with a temperature range from 283 K to 323 K, and at atmospheric pressure. For mono n-alcohols, the solubility is the lowest in methanol, increasing with the carbon chain of the alcohols. The results were correlated with a semi-empirical equation. The experimental solubility and correlation equation in this work can be used as essential data and models in the purification process of 4-(3,4-dichlorophenyl)-1-tetralone.
Keywords: 4-(3,4-Dichlorophenyl)-1-Tetralone; Laser Technique; Solubility; Alco

Composite group vector space method for estimating melting and boiling point of pure organic compound by Wenying Wei; Zhen Wang; Yanhua Yin; Jinyu Han; Wen Xu (562-567).
Composition Group Vector Space (CGVS) method for estimating melting and boiling point T m , T b of organic compound has been proposed, and the principle of this method has been elucidated. The models for estimating T m , T b have been established and the numerical values of relative parameters have been presented. The average percentage deviations of T m , T b estimation are 7.53 and 1.58, respectively, which show that the present method demonstrates significant improvement in applicability to predict the above properties, compared to conventional group methods.
Keywords: Composition Group Vector Space; Pure; Organic Compound; Melting Boiling; Boiling Point; Estimation

There are two ways to evaluate the properties of unknown chemical compounds. One is by traditional approaches, which measure the desired data from the experiments and the other is by predicting them in the theoretical approaches using a kind of prediction model. The latter are considered to be more effective because they are less time consuming and cost efficient, and there is less risk in conducting the experiments. Besides, it is inconvenient to conduct experiments to obtain experimental data, especially for new materials or high molecular substances. Several methods using regression model and neural network for predicting the physical properties have been suggested so far. However, the existing methods have many problems in terms of accuracy and applicability. Therefore, an improved method for predicting the properties is needed. A new method for predicting the physical property was proposed to predict 15 physical properties for the chemicals which consist of C, H, N, O, S and Halogens. This method was based on the group contribution method that was oriented from the assumption that each fragment of a molecule contributes a certain amount to the value of its physical property. In order to improve the accuracy of the prediction of the physical properties and the applicability, we extended the database, significantly modifying the existing group contribution methods, and then established a new method for predicting the physical properties using support vector machine (SVM) which is a statistical theory that has never been used for predicting the physical properties. The SVM-based approach can develop nonlinear structure property correlations more accurately and easily in comparison with other conventional approaches. The results from the new estimation method are found to be more reliable, accurate and applicable. The newly proposed method can play a crucial role in the estimation of new compounds in terms of the expense and time.
Keywords: Group Contribution Method; Functional Group; Support Vector Machine; Property Estimation

Phenylbutazone was recrystallized from its solutions by using a supercritical fluid antisolvent process. It was dissolved in acetone and supercritical carbon dioxide was injected into the solution, thereby inducing supersaturation and particle formation. Variation in the physical properties of the recrystallized phenylbutazone was investigated as a function of the crystallizing temperature and the carbon dioxide injection rate. The recrystallized particles showed cleaner surfaces and more ordered morphology compared to the particles obtained by other methods such as solvent evaporation. X-ray diffraction patterns indicated that the crystallinity of the particles had been modified upon the recrystallization. Differential scanning calorimetry measurement revealed that the crystallizing temperature influenced the thermal stability of the resulting crystals. Larger crystals were produced when the carbon dioxide injection rate was reduced.
Keywords: Antisolvent; Nucleation; Phenylbutazone; Recrystallization; Supersaturation

Micronization of arbutine using supercritical anti-solvent by Chan Ik Park; Moon Sam Shin; Hwayong Kim (581-584).
Arbutine has been used as skin whitening agent in cosmetics and pharmaceuticals. The objective of this study was to precipitate arbutine micro-particles using a supercritical anti-solvent. Ethanol and supercritical CO2 were used as solvent and anti-solvent, respectively, under various conditions. The effects of pressure, temperature and solution flow rate on the particles were studied. The particle size and morphology were analyzed by field emission scanning electron microscopy.
Keywords: Arbutine; ASES; Supercritical; Anti-solvent

A simulation of the three-dimensional motion of grinding media in the stirred media mill for the research of grinding mechanism has been carried out by 3-dimensional discrete element method (DEM). The movement of ball assemblies was graphically displayed with some snapshots from start of the milling to 0.20 s. From these simulation results, the grinding zone in the mill was confirmed to be distributed into two regions, which is near the stirrer and the side wall of mill around the stirrer. The power changing the rotation speed of stirrer was examined based on the micro interactive forces at all the contact points between ball-to-ball and between ball-to-stirrer. DEM is a very powerful tool for the microanalysis of movement of balls, which could not have been solved by a conventional experimental method.
Keywords: DEM; Computer Simulation; Ball Movement; Stirred Ball Mill; Power; Grinding Mechanism

Influence of the silicon surface treatment by plasma etching and scratching on the nucleation of diamond grown in HFCVD - a comparative study by Shafeeque G. Ansari; Mushtaq Ahmad Dar; Young-Soon Kim; Hyung-Kee Seo; Gil-Sung Kim; Rizwan Wahab; Zubaida A. Ansari; Jae-Myung Seo; Hyung-Shik Shin (593-598).
A comparative study for the nucleation of diamond was carried out using surface treatment like (i) surface scratching with 1 μm diamond paste and (ii) surface etching using chlorine plasma at different RF powers (50, 100 and 150 W). Atomic force microscopic study shows variation in roughness from 31 nm to 110 nm. Scratching results in random scratches, whereas plasma etches a surface uniformly. Scanning electron microscopic observations show well faceted crystallites with a predominance of angular shaped grains corresponding to 〈100〉 and 〈110〉 crystallite surfaces for the scratched as well as plasma etched substrate. Surface etching at 150 W plasma power results in a better growth in comparison with 50 and 100 W plasma powers. Chlorine-radical is found responsible for the changes in the growth morphology. Raman spectroscopy shows a sharp peak at 1,332 cm−1 and a peak at ∼1,580 cm−1 for both samples.
Keywords: Diamond Nucleation; Surface Treatment; Plasma Etching; Cl-radical; Scratching

Effect of biobased and biodegradable nucleating agent on the isothermal crystallization of poly(lactic acid) by Kyung Su Kang; Sang Il Lee; Tae Jin Lee; Ramani Narayan; Boo Young Shin (599-608).
The effect of chemically modified thermoplastic starch (CMPS) on the thermal properties and isothermal crystallization kinetics of poly(lactic acid) (PLA) was studied by differential scanning calorimetry (DSC) and compared to that of granular starch and an inorganic nucleating agent, talc. Nucleated PLA showed an additional crystallization of PLA, which affected the melting temperature. The crystallinity and crystallization rate of PLA were considerably enhanced by addition of CMPS, even at 0.1% content, and the amount of the CMPS had little effect on the thermal properties and isothermal crystallization kinetics of PLA. The effect of CMPS as a nucleating agent was comparable to that of granular starch but slightly less than that of talc. However, CMPS can offer a fully biodegradable nucleating agent with no residues remaining for the biobased and biodegradable polymers.
Keywords: Poly(lactic acid); Nucleating Agent; Isothermal Crystallization; Chemically Modified Thermoplastic Starch

A novel method for the fabrication of highly ordered nanopore arrays with very small diameter of 14 nm was demonstrated by using low-temperature anodization. Two-step anodization was carried out at 25 V, sulfuric acid concentration of 0.3 M, and electrolyte temperature of −15 °C. After anodization, a regular pore array with mean diameter of 14 nm and interpore distance of 65 nm was formed. The pore diameter and regular arrangement were confirmed by scanning electron microscopy (SEM) and fast Fourier transformation (FFT), respectively. The present results strongly suggest that the diameter of pores in a highly ordered alumina template can be reduced by lowering the anodization temperature.
Keywords: Porous Alumina; Anodization; Pore Diameter; Pore Arrangement