Table of Content

20 April 2011, Volume 11 Issue 2

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流动与传递

Solid-Liquid Dispersion in a Stirred Tank

ZHANG You YIN Xi-xiang HUANG Xiong-bin;

. 2011, 11(2):  181-186. 

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The solid-liquid dispersion property by eight types of impeller such as four-pitched-blade turbine (PBT), Rushton turbine (RT), etc, and the influences of stirring power and impeller combinations on dispersion property were studied in a vertical stirred tank with diameter of 0.478 m. Kaolin particles were chosen as the particulate material to be dispersed in the water. The experimental results show that PBT and RT have the optimum dispersion performance, while the 2-blade CBY propeller has the shortest dispersion time. The dispersion rate is in the direct ratio of 1.08 to the stirring power. In the beginning period, the relative dispersion performance Y increases with the stirring power, but the stirring power has little influence on the dispersion performance when the relative dispersion performance Y is more than 0.999. The results also reveal that the combination of a bottom 2-blade CBY and an upper PBT has a clear advantage in continuous operation.

Coupled Modeling of Fluid Flow, Heat Transfer and Solidification of Molten Steel in a Casting Mold with Double Horizontally Stabilized Electromagnetic Brakes

YUE Qiang ZHOU Li WANG Jian-jun

. 2011, 11(2):  187-192. 

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A three-dimensional model of liquid steel flow, temperature and solidification in a slab casting mold with magnetic induction is presented in FLUENT and magneto-hydrodynamics (MHD). The model is applied to investigate the effects of flow and heat transfer in the mold with and without electromagnetic brakes (EMB), their strength is measured at a steel plant. The results show that free face velocity and penetration depth of liquid steel can be decreased under a constant EMB strength. Electromagnetic forces can be controlled to stabilize the fluid flow in the mold cavity, and shell thickness of slab mold exit position increase 2 mm compared with the mold without EMB.

Optimization of Flow Characteristics of Molten Steel in a Five-strand Tundish

HAN Jian-jun FAN Xin-you LI Shi-qi WU Long YAN Guo-an GONG Fei DONG Da-xi

. 2011, 11(2):  193-198. 

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Flow characteristics in a five-strand tundish No.0 of Shijiazhuang Iron & Steel Co. Ltd. were optimized by hydraulic simulation. Coefficient of variance was used to describe the consistency of molten flow characteristics among strands in the multi-strand tundish. Mean residence time was used as the main evaluating indicator, and peak time, minimum residence time and coefficient of variance were considered as minor evaluating indicators. There were four impact factors considered, turbulence inhibitor, retaining wall, retaining dam and casting speed. The conclusions can be drawn as follows. Compared with that using circular turbulence inhibitor, the mean residence time could be extended by 12 s if quadrate turbulence inhibitor was used. Using V-type retaining wall, the consistency of melt flow characteristic among strands could be better. In addition, the retaining dam should not be used in the tundish, and the casting speed should be kept at 1.5 m/min.

Effect of Bed Expansion Height on Electrogenesis Capacity of Anaerobic Fluidized Bed Membraneless Microbial Fuel Cell

YUE Xue-hai ZHAO Shu-ju WANG Xu-yun GUO Qing-jie

. 2011, 11(2):  199-203. 

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Anaerobic fluidized bed microbial fuel cell (MFC) with 40 mm in diameter and 600 mm in height was employed to investigate the effect of fluidization bed expansion on the electrogenesis capacity of MFC. Three different cathodes were investigated for cathode positions at 150, 250 and 350 mm above distributor. When the expansion height was less than 170 mm, the electrogenesis capacity at cathode 1 was the maximum, up to 347.1 mW/m2. The power density decreased with decreasing cathode position along the bed height. When the expansion height ranged from 170 to 270 mm. The electrogenesis capacity at cathode 2 was larger than that at cathodes 1 and 3, which approached 361.0 mW/m2 when the flow rate of wastewater was kept at 8.35 mm/s. When the expansion height of fluidization bed was 270 to 400 mm, the electrogenesis capacity of three cathodes was all decreased. However, cathode 3 had a minimum decline value, 297.5 mW/m2 at the flow rate of wastewater of 10.61 mm/s. The power density increased with increasing cathode position along the bed height. The results were due to the effects of the flow rate on the mass and electron transport efficiency in anode chamber, and the effects of the flow rate on the growth of microbial film.

Experimental Study on Mixing Performance of Improved Intermig Impeller

WANG Shu-chan ZHANG Ting-an ZHANG Chao LIU Yan ZHAO Qiu-yue

. 2011, 11(2):  204-208. 

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In order to study mixing performance of a new-style impeller, improved Intermig impeller, in an unbaffled stirred tank of alumina seed precipitator, the profiles of local solid concentration in a liquid-solid system of water-glass bead particles were measured using a PC6D fiber optic reflection probe and analyzed at different conditions. The results showed that the high agitation speed and viscosity of the system are more conducive to uniform distribution. When m=3.50′10-3 Pa·s and n=172 r/min, the multiple relationship of average values of the practice and theory is 1.011 times. It shows that the experimental concentration is closer to theoretical one under this condition, resulting in more even mixing.

反应与分离

Dehydration and Electrodeposition of Magnesium from MgCl2×6H2O in Ionic Liquids

MA Mei-yan ZUO Yong ZHANG Hai-lang CAI Ying-jun ZHANG Suo-jiang

. 2011, 11(2):  209-214. 

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The solubility and dehydration of MgCl2×6H2O in various ionic liquids (ILs) were investigated. The results showed that MgCl2×6H2O and MgCl2 were well soluble (solubility 20%~70%) in hydrophilic ionic liquids, especially those with chloride anion. The moisture content after dehydration was lower than 1′10-4(w) which satisfies the request of electrodeposition. The electrodeposition of magnesium from various MgCl2-ILs systems was further studied. The cathodic limit of ionic liquids (including alkylimidazolium, trialkylimidazolium and quaternary ammonium ILs), the reduction potential of magnesium and deposition process were observed using cyclic voltammetry, SEM and EDS measurements. It is shown that magnesium can be deposited from MgCl2-ILs systems, but the reduction potential of magnesium is not more negative than that for the reduction of ionic liquids cation and reversibility of magnesium is not very well.

Effect of Microwave Irradiation on the Penetrability and Dewaterability of Dewatered Municipal Sewage Sludge

XIAO Chao-lun TANG Jia-li PAN Feng WANG Juan SUN Yang LIU Hui-zhou

. 2011, 11(2):  215-220. 

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The penetrability of microwave at the frequency of 2450 MHz and the power of 500 W was studied in dewatered municipal sewage sludge, and the change of dewaterability of sludge was also studied in the process of microwave irradiation. The results showed that the penetration depth of microwave was 8.7 mm, and the dewaterability of sludge could be improved obviously by proper irradiation. The water content of sludge after centrifugation in the top container was decreased from 80.61% to 75.09% after the sludge was treated for 5 min by microwave irradiation. When the temperature was above about 60℃, microbial cells in sludge began to be broken in large quantities and the intracellular water was released, and the water content of sludge after centrifugation decreased with increasing temperature. When the temperature was above 88℃, the concentrations of extracellular polymeric substances (EPS) had no obvious increase but the hydrophilicity of EPS decreased, and the dewaterability had the quick improvement.

Chelating Adsorption Behavior of Imido-acetic Acid-type Composite Chelating Adsorption Material IAA-PEI/SiO2 for Heavy Metal Ions

LI Yan-bin GAO Bao-jiao DU Rui-kui;

. 2011, 11(2):  221-226. 

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Polyamine polyethyleneimine (PEI) was grafted onto micron-sized silica gel particles, obtaining the grafted particles PEI/SiO2. Subsequently, the nucleophilic substitution reaction between chloroactic acid and the first and secondary amino groups of PEI/SiO2 was performed, forming the imido-acetic acid (IAA)-type composite chelating adsorption material IAA-PEI/SiO2. The chelating adsorption characteristics of IAA-PEI/SiO2 to heavy metal ions, and the adsorption mechanism were investigated. The experimental results showed that IAA-PEI/SiO2 possesses strong adsorption ability for heavy metal ions by right of the synergism of electrostatic interaction and coordination chelating action between imido-acetic acid groups and heavy metal ions. The adsorption process of IAA-PEI/SiO2 towards heavy metal ions is exothermic. In the pH range, the hydrolysis of the heavy metal ions can be inhibited, the chelating adsorption ability of IAA-PEI/SiO2 to heavy metal ions increases with increasing pH value. The adsorption ability order of IAA-PEI/SiO2 to heavy metal ions is Ni2+>Pb2+>Cu2+>Cd2+.

Adsorption Behavior of Iron Oxide Coated Pumice for Phosphate

PAN Yong-zhang ZHU Feng

. 2011, 11(2):  227-232. 

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Natural pumice was modified with iron oxide and tested as an adsorbent for the removal of phosphate from water, and the thermodynamics and kinetics of phosphate adsorption from aqueous solution using iron oxide coated pumice (IOCP) were investigated. The results indicated that the Langmuir model fit the equilibrium data better than the Freundlich model. The maximum adsorption capacity of 0.63~1.20 mm IOCP for phosphate was found to be 0.245 mg/g at 298 K. Evaluation of the experimental data in terms of adsorption kinetics revealed that the adsorption of phosphate onto IOCP followed well the pseudo-second-order kinetic model. The calculated values of DG0, DH0 and DS0 at different temperatures indicate that the adsorption is a spontaneous and endothermic process. The results of SEM and EDAX analysis showed that phosphate ions were chemisorbed on the surface of IOCP.

Adsorption and Desorption Behavior and Mechanism of Vanadium on SQD201 Resin

SHI Mei-lian DUAN You-gou YAN Wen-bin GAO Feng HUA Jun

. 2011, 11(2):  233-238. 

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With the static experiments, the exchange equilibrium and kinetics of adsorption and desorption of vanadium by SQD201 resin were studied, the affecting factors of the ion exchange process such as pH, temperature and the concentration of vanadium were investigated in detail. The results indicated that the static saturated adsorption capacity was 573.80 mg/g at the conditions of pH was 2.0, temperature was 298 K and the concentration of vanadium was 0.040 mol/L. The adsorption of vanadium on the resin was an endothermic process. The equilibrium adsorption data fitted to Langmuir isotherms. Kinetics analysis showed that the adsorption and desorption process was mainly governed by ion diffusion through particle, the adsorption activity energy was 20.41 kJ/mol and the desorption activity energy was 22.21 kJ/mol. The results of adsorption mechanism analysis show that the main anion of vanadium adsorbed by SQD201 resin was H2V10O284-, which the theoretical mole ratio with resin was 1:4.

Effects of Anions on Deep Desilication of Sodium Aluminate Solution

WANG Ya-jing LI Hong-liang; PANG Chang-jian ZHAI Yu-chun ZHANG Zheng

. 2011, 11(2):  239-243. 

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The influences of anions (SO42-, CO32- and Cl-) on deep desilication of sodium aluminate solution were investigated. The optimal conditions of desilication were studied by examining the temperature, time, anion and Al2O3 concentration, ak and stirring speed. Under the conditions of 95℃, Al2O3 150 g/L, ak 1.5, and stirring speed 867 r/min, after 110 min the silica module was above 3815, and at the Al2O3 concentration of 30 g/L, the silica module was above 3943, 3545 and 3221. When the concentration of anion was 0~70 g/L, deep desilication was promoted by SO42-, but deep desilication was promoted firstly and then inhibited by CO32- and Cl-. Silica residue was analyzed by XRD, and the desilication mechanism by SO42-, CO32- and Cl- clarified.

Simulation of Chlorination of Benzene and Distillation of Chlorobenzene in a Combined Reaction and Distillation Tower with Side Reactors

BAI Yang-jin BO Cui-mei DING Liang-hui QIAO Xu

. 2011, 11(2):  244-248. 

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The structure of side reactors distillation column (SRC) can improve the production process selectivity and conversion rate effectively. The concept of independent reactor calculating is introduced to set up the multi-lateral line feeding equilibrium model of SRC, and Newton-Raphson method used for solving the MESH equations of the model. The method is applied in the distillation simulation for production of chlorobenzene. The model has good convergence effect. In given simulation conditions, when the feeding molar flow rate of chlorine is 8 kmol/h, the product purity of benzene chloride 96.8% and the best feeding molar flow rate of benzene 7.77 kmol/h. The simulation results can be used to guide the production process of benzene chlorination.

Leaching of Valuable Metals from Calcined Spent Lithium-ion Batteries

JIE Xiao-wu WANG Chen-yan LI Dun-fang YIN Fei CHENG Yong-qiang YANG Yong-qiang

. 2011, 11(2):  249-253. 

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Leaching behavior of valuable metal elements in roasted spent lithium-ion batteries was investigated. The pulp of LiCoO2 or Co3O4 mixed with concentrated sulfuric acid and one of sodium sulfate, potassium sulfate and ammonium sulfate was heated in the temperature range from 150℃ to 300℃. The cobalt-containing transformation products were then subject to dissolution in hot water. The dissolution rate of transformation products of LiCoO2-containing pulp was 56.4%~100%, and that of Co3O4-containing pulp 97.2%~100%. M2Co(SO4)2×nH2O (M=Na, K, NH4+) phases formed in the transformation products with sodium sulfate, which were easily dissolved in hot water. Moreover, the mixture of roasted residue of spent lithium-ion batteries with concentrated sulfuric acid and sodium sulfate was heated at 400℃. All of the Li and Co elements in the mixture were leached out in hot water at 70℃, and the leaching rates of Cu and Al were greater than 99%.

Extraction of Alumina from Coal Fly Ash with Sulfuric Acid Leaching Method

LI Lai-shi LIU Ying-ying ZHAI Yu-chun WU Yu-sheng

. 2011, 11(2):  254-258. 

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Coarse g-Al2O3 powder was prepared through acid leaching, solid-liquid separation, crystallizing and aluminum sulfate decomposing processes using coal fly ash and concentrated sulfuric acid as raw materials. The metallurgy level Al2O3 can be obtained by disposing coarse g-Al2O3 powder with Bayer process. The optimum conditions of acid leaching process were determined by experiments. The extraction rate of Al2O3 can be stabilized at about 87% under these conditions. The thermodynamics and kinetics of sulfuric acid leaching process were studied with irreversible thermodynamics.

过程与工艺

Kinetic Study of Co-b-Zeolite for Selective Catalytic Reduction

MAO Shu-hong WANG Run-ping CHI Yong-qing WANG Yan ZHANG Qin-hua CONG Yan-qing

. 2011, 11(2):  259-268. 

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The effects of grain size, space velocity, temperature and reactant concentration on the kinetics of NOx reduction with propane over Co-b-zeolite catalyst were investigated. The external mass transfer phenomenon was examined by varying the space velocity. The results show that the transfer can be negligible when the space velocity is greater than 60000 h-1 in low temperature range. However, the transfer exists at high temperatures even when the space velocity reaches a high level. Variation of the catalyst grain size from 0.05 to 0.125 mm does not change the conversion rate of NOx. The concentrations of components, NOx, C3H8 and O2, were also investigated to have a better understanding of mechanism. Based on the experimental data, the selectivity formula was proposed. The results shows that lower temperature is helpful to get higher selectivity as the activation energy of hydrocarbon oxidation, Ea,2, is greater than that of NOx reduction, Ea,1, (Ea,2>Ea,1). High NOx concentration and low C3H8 concentration are beneficial to high selectivity. However in order to maintain high activity simultaneously, the temperature and C3H8 concentration should be high enough to promote NOx reduction. 10%(j) H2O and 75′10-6(j) SO2 were introduced into the reaction system, and Co-b-zeolite shows strong resistance to water and SO2.

Experimental Investigation on Iron Based Chemical Looping Process for Adjusting H2/CO Ratio in Syngas and Hydrogen Generation

SU Yu-yan LI Song-geng SONG Wen-li LIN Wei-gang

. 2011, 11(2):  269-275. 

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The influences of operation conditions on the iron base chemical looping hydrogen generation process for adjusting H2/CO ratio in syngas and hydrogen generation for Fischer-Tropsch (FT) synthesis were studied. The results show that when the H2/CO ratio is 0.5 in the syngas, the H2/CO ratio in exhaust gas varies from 0.87 to 0.53 as the temperature increases from 500 to 800℃. By adding suitable amount of steam in the reduction stage, the adjusting capacity can be enhanced dramatically and the hydrogen amount in the oxidation stage increases. The additional steam in the reduction stage can also restrain carbon deposition effectively and make the hydrogen purity approach 100%. The reactivity and recyclability can be enhanced by adding graphite as pore-forming additive. After 6 cycles, the practical hydrogen amount can still reach 40% of the theoretical amount for the particles with the graphite as additive (20% for original particles) and reserve pore structure after reaction while the particles without graphite are almost completely sintered.

Treatment of High-concentration Wastewater from Oil Refinery for Meeting Discharge Standard

ZHONG Hua-wen ZHOU Ru-jin CHEN Qing-lin SU Lin-hui CHENG Li-hua XIE Wen-yu

. 2011, 11(2):  276-282. 

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Aiming at the characteristics of high content of sulfur and phenolic pollutants and poor biochemical properties of high-concentration wastewater from oil refinery, a combined technology of biological desulfurization, Fe-C micro-electrolysis, biological phenol removal, adsorption-biodegradation process (AB method) and internal recycle biological aerated filter (BAF) was developed. The results showed that dissolved oxygen of the bio-reactors of biological desulfurization, biological removal of phenol, AB method and internal recycle BAF were controlled at 2.0 mg/L, 2.0~2.4 mg/L, 0.6~1.0 mg/L in section A, 1.5~2.0 mg/L and ≥2.4 mg/L in section B by AB method respectively, hydraulic retention time (HRT) in 8~12, 8~12, 5~6 and 2.5~3.0 h respectively, Fe/C mass ratio of the Fe-C micro-electrolysis at 3~4, pH value in 3.0~3.8, and reaction time for 30 min, the average mass concentrations of sulfide, volatile phenol, COD, ammonia nitrogen and oil in the wastewater were reduced from 705, 225, 4333, 38.6 and 30.0 mg/L to 0.3, 0.07, 80.5, 11.6 and 2.9 mg/L respectively, thus meeting the national discharge standards.

Experimental Study on Dual Bed Decoupling Combustion of Distilled Spirits Lees

YAO Chang-bin WANG Yin; DONG Li BIE Ru-shan XU Guang-wen

. 2011, 11(2):  283-288. 

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A dual-bed decoupling combustion technology was proposed to burn the industrial biomass residues rich in water and N generated in various light industry processes. The necessity and feasibility of this technology was investigated through experiments and process simulation by employing the distilled spirits lees to represent the industrial biomass residue. The results showed that in a fluidized bed the higher the water content, the longer the ignition time for the distilled spirits lees. And the combustion is unstable when the water content is higher than a certain value. For high N in feedstuff the NO concentration in the flue gas was found to be higher than 800 mg/m3. Burning the fuel via the decoupling combustion realized stable combustion and reduced the NO emission by more than 50%. The distilled spirit lees were found to be easier to burn out than the rice husk, and no ash melting and agglomeration were found in the quartz sand fluidized bed running in 500~900℃. The process simulation via Aspen plus demonstrated that the stable autothermal combustion could be realized via the duel bed combustion even for the distilled spirits lees containing water of up to 55%(w).

Alkylation of Benzene with Ethyl Chloride Catalyzed by Lewis Acidic Ionic Liquids

WANG Li LUO Guo-hua XU Xin LIU Jian-wei

. 2011, 11(2):  289-293. 

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Lewis acidic ionic liquid was used to catalyze the alkylation reaction of benzene with ethyl chloride. The effects of different Lewis anion catalysts, the feeding method, the molar ratios of AlCl3/[Et3NH]Cl, reaction temperature, the molar ratios of benzene to ethyl chloride, the amount of the catalyst and the reusability of the ionic liquid on the alkylation reaction were studied. Under the optimal conditions of 70℃, molar ratios of benzene/ethyl chloride at 10, amount of catalyst at 10% by weight, the benzene conversion rate reached 9.48% and the ethyl benzene selectivity was 93.65%, further more, the [Et3NH]Cl-2AlCl3 (molar ratio of AlCl3 to [Et3NH]Cl was 2) as a catalyst for such reaction could be recycled, and the catalyst activity and selectivity had minor changes after 10 cycles.

Experimental Study on Vacuum Thermal Reduction of Ascharite Mineral with Silicon as Reductant

WU Xiao-lei PENG Jian-ping FENG Nai-xiang WANG Zhi-hui CHENG En-qing

. 2011, 11(2):  294-298. 

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Vacuum thermal reduction technology was used to extract magnesium from ascharite mineral. At the same time, boron in the raw material was kept in residue. The residue could be used as raw materials to make non-alkali glass fiber. Calcined material and residue were analyzed by XRD and compared. Based on thermodynamic analysis, the Gibbs free energy and critical temperature of reduction of ascharite with silicon were calculated. As a result, the critical temperature was 661℃ when the air pressure in the system was 4 Pa. The best calcination conditions were obtained as 1000℃ for 30 min. In addition, the reduction rate of magnesium increased sensibly as long as CaO addition mass was increased.

Experiment and Mathematical Simulation on Reduction of Fine Iron Oxide with Hydrogen at Medium-low Temperatures

LI Qiu-ju LIAO Zeng-li WANG Xiu HONG Xin

. 2011, 11(2):  299-303. 

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Weight loss method was used to study the reduction of fine iron ore with hydrogen at the temperatures from 500 to 600℃. Considering the effects of gaseous concentration and reaction heat, a non-isothermal kinetics model coupling heat and mass transfer with chemical reaction was developed to simulate the reduction process of fine oxide ore. Reduction degrees at different temperatures and times were obtained through numerical calculation. Distribution and variation of temperature and gas concentration inside the fine iron oxide particles were also simulated. The simulation result showed that fine ore particles were completely reduced within 20 min at 600℃, and hydrogen diffused to their center within 15 min.

生化工程专栏

Selection of Strain Exposed under Plasma Discharge with Enhanced 1,3-Propanediol Production and Kinetic Analysis of Batch Fermentation

LI Shuang TENG Hu XIU Zhi-long

. 2011, 11(2):  304-311. 

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The strain of Klebseilla pneumoniae was exposed under dielectric barrier discharge plasma at air atmospheric pressure. The physical parameters of plasma discharge and optimum conditions of mutagenesis were established. The exposed cell suspension was acclimatized repeatedly under different concentrations of substrate and product, respectively, and single colony was selected by 96-hole plate. A mutant with improved 1,3-propanediol (1,3-PD) production was obtained and designated as Kp-M2. Compared with wild type, the 1,3-PD concentration was increased by 43% in batch fermentation. The kinetic models of Kp-M2 and wild type in batch fermentation were proposed based on the Logistic and Luedeking-Piret equations of cell growth, product formation and substrate consumption. The maximum specific growth rate, formation coefficient of 1,3-PD coupling cell growth and yield coefficient of 1,3-PD on glycerol in Kp-M2 were significantly higher than those of wild type.

Extraction of Soybean Protein Isolate Using Multi-stage Countercurrent Solid-Liquid Extraction Method

Gao Jian-Ping LIU Lin WANG Ming-lin ZHANG Gui-feng HUANG Yong-dong; LIU Yong-dong SU Zhi-guo

. 2011, 11(2):  312-317. 

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Release behavior of proteins in soybean meal during their extraction process using high performance liquid chromatography-mass spectrometry was investigated. The possibility for extraction of soybean protein isolate using multi-stage countercurrent solid-liquid extraction (MSCSLE) was also studied. The result indicated that 2S protein showed a higher release rate and more than 80% of total 2S proteins were released after extraction in two times. The total release rate of 7S and 11S proteins reached 69% after three times of extraction, indicating that 7S and 11S fractions had a lower release rate during extraction process. Increasing the concentration gradient between the solid and liquid or extending the extraction time enhanced the release of 7S and 11S fractions. The concentration of total proteins obtained using MSCSLE was higher than that obtained by multi-time extraction, resulting in higher 7S and 11S recovery rate. Under the same recovery rate of soybean protein isolate, 11% of water could be saved. During precipitation, 8% of total 7S and 11S protein could be recovered.

Synthesis of Molecularly Imprinted Polymer Microspheres for Cholesterol and Their Adsorption Property

GUO Yong-Xue LI Tong WANG Li-hong WU Di ZHOU Li-li

. 2011, 11(2):  318-323. 

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Molecularly imprinted polymer microspheres (MIPMs) were prepared by precipitation polymerization of methacrylic acid (MAA) and ethylene dimethacrylate (EDMA) using cholesterol (CHO) as template molecule in toluene-acetonitrile mixed solvent (9:1, j). The MIPMs were investigated in equilibrium binding experiment and Scatchard analysis to evaluate the binding characteristics and recognition mechanism of MIPMs in aqueous solution. Scatchard analysis showed that two classes of binding sites were produced in the polymer matrix under the studied concentration. Their dissociation constant (Kd) and apparent maximum binding capacity (Qmax) were 0.86 mmol/L, and 80.4 mmol/g for high affinity binding sites and 0.39 mmol/L and 61.6 mmol/g for low affinity binding sites. The CHO imprinted polymer micro-spheres synthesized in this method had better performance and could be used for separation, enrichment and analysis of CHO.

Asymmetric Reduction of 3-Chloropropiophenone with Saccharomyces cerevisiae in Aqueous System

YANG Jin FANG Shi-yin SHI Xian-ai

. 2011, 11(2):  324-328. 

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Asymmetric reduction of 3-chloropropiophenone with Saccharomyces cerevisiae in aqueous system was studied. The results showed that the preference product configuration was (S)-3-chloro-1-phenylpropanol, and the reduction was catalyzed by a single reductase or several isozymes with the same catalytic characteristics. In the concentration range investigated, neither substrate nor product inhibitions were found, but the toxicity of product which induced the cell inactivation prevented the yield from elevation. The proper concentration of inclusion complexes in the reaction system assisted to improve the yield, for example, when the concentration of Tween-80 and b-cyclodextrin was 2.0 and 5.0 mmol/L, the yields would be increased from the control of 64.7% to 73.8% and 70.6%, respectively. The additives with the abilities of inclusion and improvement of cell membrane permeability would take better effect on the yield than those only with the ability of inclusion.

材料工程专栏

Measurement of Area Resistance of Ion-exchange Membrane and Its Influential Factors

ZHAO Xi-yun ZHANG Li-ye; SHI SHAO-yuan CONG Wei

. 2011, 11(2):  329-335. 

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Area resistance (Ra) of several kinds of ion-exchange membrane (IEM) is determined using alternating current method by self-designed device and optimized measuring conditions. Influential factors of Ra value are also studied. The distance between the electrodes of conductivity cell is 10 mm and the chamber diameter 20 mm. The frequency of alternating current is 100.0 kHz and voltage 100 mV. For the membranes of JAM and JCM series, Ra shows negative correlation with water content. Ra of anion membrane RXAM-1003 and cation membrane RXCM-1003 varies greatly for different counter ions, while it changes slightly for common ions. However, Ra of bipolar membrane RXBM-1003 is affected by both counter ions and common ions. Ra declines significantly as solution concentration increases when the concentration is below 0.5 mol/L, and it has a relatively constant value when the concentration is above 1.0 mol/L.

Synthesis of N and Al Co-doped TiO2 Particles with Visible Light Degradation Property via Solid State Reaction Route

JIANG Tian-zhi LIU Shao-you FENG Qing-ge LONG Bu-ming;

. 2011, 11(2):  336-342. 

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N and Al co-doped TiO2 (N-Al-TiO2) particles were successfully synthesized via a solid-state reaction route. Their properties were characterized by XRD, N2 adsorption-desorption, UV-Vis and XPS. The photodegradation of neutral red (NR) on the N-Al-TiO2 material irradiated with visible light was investigated. The XPS results clearly show that both N and Al have been incorporated into the lattice of TiO2. The N?Ti?O and Ti?O?Al bonds formed by lattice substitution and Ti?N?O and Ti?O?N bonds configured by interstitial doping on the N-Al-TiO2 material surface are presented. Compared with pure TiO2, the photodegradation properties of NR on the N-Al-TiO2 shows excellent visible light catalytic properties, the degradation rate of NR is 95.8% in 2 h, and the degradation process of NR follows the principle of pseudo-first-order reaction.

Distribution of Carboxyl Groups in Monodispersed Poly(N-Isopropylacylamide-co-Acrylic Acid) Microspheres Prepared by Membrane Emulsification

SI Tian-bao QIN Jia WANG Yu-xia MA Guang-hui

. 2011, 11(2):  343-348. 

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Temperature-/pH-responsive monodispersed poly(N-isopropyl acrylamide-co-acrylic acid) [P(NIPAM-co-AAc)] microspheres were prepared by Shirasu porous glass membrane emulsification at room temperature with N,N,N￠,N￠-tetramethylethylenediamine as accelerator and cyclohexane/trichloromethane mixture as oil phase. The monodispersed P(NIPAM-co-AAc) microspheres with controllable diameter could be reproducibly obtained with cyclohexane-trichloromethane mixture (volumetric ratio 7:3) as oil phase and two stage stirring speeds (140 and and 170 r/min) under the membrane emulsification pressure of 2 kPa. Conductometric titration was used to determine the distribution of carboxyl groups in the microspheres. Four-step titration curves of all the P(NIPAM-co-AAc) microspheres with different acrylic acid contents were obtained. With the increase of AAc content, the amounts of both exterior carboxyl and embeded carboxyl groups increased gradually, but the percentage of exterior carboxyl groups increased firstly, then remained at a fixed value. The highest percentage of exterior carboxyl groups was obtained with 15%(w) acrylic acid in the microspheres.

Study on Microstructure of Slag Film for Mold Fluxes

YANG Bo TANG Ping WEN Guang-hua ZHU Xin-bai YU Xiong

. 2011, 11(2):  349-354. 

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Slag films obtained from a plant and heat flux simulator of mold slag film in different times were analyzed on the properties such as thickness, type and distribution of crystals, and particle size of crystals. The results show that the thickness and crystallization rate of slag film obtained from the heat flux simulator of mold slag film in 45 s immerse time of copper probe are similar to those obtained in the plant near meniscus. Crystal distribution of slag film obtained from the plant evolving with position is similar to that from laboratory evolving with time. Solid slag film obtained from the plant and laboratory has coincidental type of crystals, but the crystal size is different. Therefore, we can through the heat flux simulator of mold slag film simulate the practical crystallization behavior of slag film in the mould conveniently and efficiently.

Fractal Study on Microwave Modification of Blast Furnace Sludge Particles

GAO Zhi-fang LI Liao-sha SU Shi-huai WU Xiao-hua LI Liao-sha

. 2011, 11(2):  355-360. 

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The effects of microwave treatment on the fractal characteristics of blast furnace sludge and relative mechanism were studied. Particle size distribution, morphology and chemical changes were analyzed. The results show that the morphology features of iron bearing sinter and coke particles, being the main constituents of blast furnace sludge particles, were remarkably changed by microwave heating. So that the surface roughness, porosity and specific surface area on the modified particle surface were all increased obviously. Combining fractal model, the fractal dimensions of sinter, coke particles and the other subsidiary components in the sludge increased from 1.27, 1.14 and 1.57 to 1.51, 1.32 and 1.61, respectively. The microwave modification mechanism on the sludge particles was related to two aspects: (1) different mineral phases existing in the sludge particles inclined to dissociate each other due to their different microwave absorbability, and (2) some recombination or reconstruction of matters or structure resulted in structural defects, which had great influences on the surface characteristics and chemical properties.