Table of Content

20 October 2011, Volume 11 Issue 5

Previous Issue    Next Issue

生化工程专栏

Asymmetric Reduction of 3,5-Bistrifluoromethyl Acetophenone with NADH Regeneration by Immobilized Cells of Saccharomyces rhodotorula in Aqueous-Organic Solvent Biphasic System

ZHANG Fang XUE Ying LI Li WANG Min

. 2011, 11(5):  0-0. 

Asbtract ( )   PDF (203KB) ( )  

Related Articles | Metrics

Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce (S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system. The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product. Organic solvents were rated by their biocompatibility and conversion potential. The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration. Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e. The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.

流动与传递

Mathematical and Physical Simulation of New Cathode Structure of Aluminum Electrolytic Cells

LIU Yan ZHANG Ting-an ZHAO Qiu-yue LI Chong WANG Hong-xing ZHANG Jun FENG Nai-xiang

. 2011, 11(5):  721-728. 

Asbtract ( )   PDF (540KB) ( )  

Related Articles | Metrics

Using cold water model experiments based on the principle of similitude, the level fluctuations by anode gas disturbance in an aluminum electrolysis cell were studied. By means of high-speed photography, the level fluctuation images of new cathode structure electrolytic cell of cold water model in different operate parameters were obtained. The maximum surface wave height was obtained by using the professional image analysis software Image-Pro-Plus 6.0 to deal with fluctuations in the captured static figures. Moreover, mathematical simulation on the anode structure of cell with Fluent 6.2.16 was also carried out. The results show that the fluctuation in new cathode structure water model of aluminum electrolysis is decreased significantly compared with that of normal cathode structure water model under the same experimental conditions. In the simulated water model cell with new cathode structure, interface fluctuation amplitude will be reduced significantly along with increasing of the anode cathode distance, increasing of the electrolyte level and decreasing of gas flow rate. The fluctuation amplitude caused by the gas from 1/2 anode is not much different from that of traditional anode, 1/4 anode can reduce waves better, but chamfer has almost no impact on the fluctuation.

Numerical Simulation on Concentration Distribution of Particles in the Feeding Pipe of a Superfine Classifier

DIAO Xiong LI Shuang-yue LI Liang-chao HUANG Peng

. 2011, 11(5):  729-735. 

Asbtract ( )   PDF (345KB) ( )  

Related Articles | Metrics

RNG k-e turbulent model and the stochastic track model were respectively adopted to simulate the particle concentration distribution characteristics in the feeding pipe of a superfine classifier SCX. The effects of inlet solid concentration, inlet velocity and particle diameter on the concentration distribution of particles were analyzed. The results show that the distribution fluctuates significantly near the bending outlet, but it becomes more stable from the bending outlet of 6 times pipe diameter. The particle concentration in the vertical section can be divided into high and low concentration areas. The dimensionless radius (r/R) of two areas is in a certain range. In the X direction, the low concentration range is -1

Numerical Studies on Fluid Flow and Heat Transfer in the Shell Side of Reticulation Orifice-baffle Longitudinal Flow Type Heat Exchanger

WANG Cui-Hua DAI Yu-Long WU Jian-hua ZHAN Hong-ren

. 2011, 11(5):  736-741. 

Asbtract ( )   PDF (251KB) ( )  

Related Articles | Metrics

Numerical simulation of fluid flow and heat transfer in the shell side of reticulation orifice-baffle longitudinal flow type heat exchanger is carried out with CFD software. Heat transfer enhancement principle of the reticulation orifice-baffle is summarized, and the influences of space between baffles (L), and open area ratio (y) on its heat transfer and pressure drop Dp analyzed, and correlations are developed for the models. The results indicate that jet flow and second flow appear after fluid leaves the reticulation orifice-baffle, which enhance heat transfer of fluid in the shell side. Compared with plate baffle heat exchangers within Reynolds number Re=2300~6300, Nusselt number (Nu) of the reticulation orifice-baffle heat exchanger is about 50% higher than that of the plate baffle heat exchanger, while its shell side pressure drop is about 2.5 times higher than that of the plate baffle heat exchanger. In the range of study, both Nu and pressure drop rise with L or y decreasing, and the influences of L or y on Nu and Dp increase with the increase of Re, but with L or y decreasing, increasing speed of Dp is obviously bigger than that of Nu.

Effects of Liquid Properties on Liquid Entrainment in a New Scrubbing-cooling Chamber

LIN Lan WANG Yi-fei GUO Qiang-qiang WANG Fu-chen

. 2011, 11(5):  742-746. 

Asbtract ( )   PDF (292KB) ( )  

Related Articles | Metrics

The effects of liquid properties on liquid entrainment in separation space above the bubbling zone in a new scrubbing-cooling chamber were investigated by isokinetic sampling method. The experimental results showed that at the same static liquid level, with the increased of gas velocity, the height of gas-liquid separation space decreased and the amount of liquid entrainment E increased. E generally changed little at the outlet, while it changed a little smaller near the wall, which was mainly influenced by gas circumfluence flow. E increased with the decrease of surface tension and decreased with the increase of viscosity. E increased 2.5 times when surface tension decreased from 72.8 to 25.8 mN/m, and increased 1 time when the viscosity increased from 1 to 2.3 mPa×s. Liquid properties had a significant impact on the amount of liquid entrainment. An empirical formula for E and physical parameters was also established, which provided theoretical basis for improving interior structure in scrubbing-cooling chamber.

反应与分离

Leaching of Vanadium from Vanadium-containing Residue by NaOH Sub-molten Salt

LI Lan-jie CHEN Dong-hui BAI Rui-guo ZHENG Shi-li DU Hao WANG Shao-na WANG Shao-na

. 2011, 11(5):  747-754. 

Asbtract ( )   PDF (782KB) ( )  

Related Articles | Metrics

The major reaction factors of vanadium leaching process from vanadium-containing residue using NaOH sub-molten salt were studied, and the optimum process parameters obtained. By analyzing the decomposition process of vanadium-containing residue, the reaction mechanism was obtained at the same time. The significance of reaction temperature, particle size, reaction time, and NaOH-to-residue mass ratio on vanadium extraction was studied. The orthogonal experimental results showed that the impact order of reaction factors was reaction temperature > reaction time > NaOH-to-residue mass ratio with respect to vanadium recovery. Under the conditions of reaction temperature 170℃, NaOH-to-residue 4:1, stirring speed 700 r/min, particle size -74 μm and reaction time 3 h, leaching rate of vanadium was higher than 90%. The leaching process of vanadium, with activation energy 27.69 kJ/mol, was controlled by the chemical reaction in the initial reaction process. Acmite was decomposed, and dissoluble vanadium dissolved into NaOH solution, when the residue was decomposed by NaOH sub-molten salt.

Penetration of Electrolyte Containing KF and LiF into Graphite Cathode during Aluminum Electrolysis

ZHANG Yue-hong ZHAI Xiu-jing WANG Yao-wu PENG Jian-ping LI Bin-chuan FENG Nai-xiang

. 2011, 11(5):  755-760. 

Asbtract ( )   PDF (534KB) ( )  

Related Articles | Metrics

The effects of KF and LiF contents in the melt electrolyte, current density and molecular ratio of NaF to AlF3 on the penetration into graphite cathode were investigated during aluminum electrolysis using NaF-AlF3-Al2O3-KF-LiF system in laboratory scale. Alkali metals including K, Na and Li penetrated into graphite cathode were detected. It was found that K and Na were converted into graphite intercalation compounds (GICs) as penetrating into cathode, and that Li reacted with C Li2C2 formed on the surface of cathode. The penetration deepness of the alkali metals increased with increasing of content of KF in the melt. And deeper penetration in graphite cathode was observed as increasing of current density and molecular ratio of NaF to AlF3. When the KF content was not more than 3%(w), electrolysis operation with the appropriate current density and molecular ratio could reduce the cathode destructivity caused by the alkali metals penetration.

Dissolution Behavior of Vanadium from Vanadium-bearing Steel Slag in KOH Sub-molten Salt

GAO Ming-lei CHEN Dong-hui LI Lan-jie DU Hao ZHENG Shi-li

. 2011, 11(5):  761-766. 

Asbtract ( )   PDF (512KB) ( )  

Related Articles | Metrics

The dissolution behavior of vanadium from vanadium-bearing steel slag was studied by decomposing the slag with KOH sub-molten salt. The influential factors of reaction temperature, reaction time and alkali-to-slag ratio were examined for obtaining the optimum reaction conditions of vanadium leaching. And the dissolution process mechanism was also investigated. The experimental results show that the leaching rate of vanadium increased with the three factors. The phases of Ca2SiO4, Ca3SiO5, Ca2Fe2O5 in the slag would disappear, and the soluble K3VO4 and dissoluble Ca(OH)2 would be produced when the steel slag was dissolved by KOH sub-molten salt. The sedimentation effect of CaO to vanadium could be avoided by controlling the concentration of KOH. The leaching rate of vanadium was higher than 90% with the reaction temperature from 220 to 240℃, reaction time at 1 h, and mass ratio of alkli to slag at 4. Compared with traditional high-temperature calcination, the energy consumption of this dissolution process was reduced obviously, and dissolution rate was increased.

Solid State Deoxidization Kinetics of Nickel Laterite Ore

LI Bo WEI Yong-gang WANG Hua

. 2011, 11(5):  767-771. 

Asbtract ( )   PDF (285KB) ( )  

Related Articles | Metrics

Solid state deoxidization kinetics of nickel laterite ore was studied using non-isothermal thermal analysis method. The conversion function f(α) and kinetic parameters of solid state deoxidization were determined by the TG curves, kinetics model established verified, and the reduction mechanism of nickel laterite ore analyzed. The results indicate that weight-loss rate can be considered as a function of the temperature, and heating rate has less effect. There was clear relationship between calculated values for mathematical model and measured values. The process of solid state deoxidization can be divided into two stages for 473~773 and 773~1223 K with activation energy 171.91 and 52.75 kJ/mol, which are corresponding to releasing stage of volatiles and reduction of nickel and ferrous oxides. The reaction mechanism belongs to random nucleation and growth, with differential form f(a)= 1/4(1-a)[-ln(1-a)]-3.. The solid state deoxidization rate of nickel laterite ore is controlled by Boudouard reaction.

Separation of the Main Components from Ti-bearing Blast Furnace Slag by Mixed Acid Leaching Method

LI Chen QIU Ke-hui ZHANG Pei-cong CAO Lei

. 2011, 11(5):  772-776. 

Asbtract ( )   PDF (253KB) ( )  

Related Articles | Metrics

Based on the structural and composition characteristics of titanium-bearing blast furnace slag, a low temperature mixed acid leaching method was used to separate acid-soluble components from the slag into the filtrate. So the titanium was enriched relatively, the resulting titanium-rich materials could be used for industrial production. The influences of the experimental factors (mixed acid concentration, hydrochloric acid/sulfuric acid ratio, reaction time, reaction temperature and mass ratio of slag to mixed acid) on separation of its components were investigated. The results showed that an enriched residue with over 30% TiO2 could be obtained by the mixed acid leaching method and the optimum conditions were mixed acid concentration 6 mol/L (volume ratio of HCl/H2SO4=3:1), at 80℃ for 5 h, and mass ratio of acid to the slag at 1.2:1.

Solubility Measurement of Aniline Hydrochloride in C6H5OH-H2O System and Chemical Modeling of Mixed Solvent Electrolyte

SUN Shun-ping LI Zhi-bao

. 2011, 11(5):  777-781. 

Asbtract ( )   PDF (993KB) ( )  

Related Articles | Metrics

The solubility of aniline hydrochloride ([HAE]Cl) in C6H5OH-H2O system was investigated by using a dynamic method in the temperature range from 288 to 348 K. The results show that the solubility of [HAE]Cl in all cases increases with increasing of the temperature, while sharply decreases when the concentration of ethanol solution is more than 30%(w). With the purpose of investigating the phase behavior of [HAE]Cl in C6H5OH-H2O system, a mixed solvent electrolyte thermodynamic model of electrolyte NRTL (non-random two liquids) was used to predict the solubility of [HAE]Cl in various compositions of C6H5OH solution at different temperatures. New model parameters for electrolyte NRTL model were obtained via the regression of experimental solubility. The results indicate that electrolyte NRTL model can provide good prediction in the solubility of [HAE]Cl in both pure ethanol and C6H5OH-H2O system. In order to describe the phase behavior of [HAE]Cl in C6H5OH-H2O system clearly, the phase diagram of [HAE]Cl-C6H5OH-H2O system was constructed with the established mixed solvent electrolyte model.

Synthesis of 2-Phenylethanol by Bioconversion in Aqueous-Organic Solvent Two-phase System

CHEN Hong CHEN Wei-qing ZHANG Jian-fen

. 2011, 11(5):  782-785. 

Asbtract ( )   PDF (181KB) ( )  

Related Articles | Metrics

Production of 2-phenylethanol by bioconversion was performed in a two-phase system composed of water and polypropylene glycol. The molecular weight and adding volume of polypropylene glycol, shaking speed for cultivation and concentration of L-phenylalanine were investigated to improve the productivity of 2-phenylethanol. The bioconversion process was carried out in a 5 L fermentor. The results indicated that the optimal conditions for 2-phenylethanol production in two-phase system were as follows: polypropylene glycol molecular weight was 1500, adding volume half of the volume of medium, shaking speed 250 r/min, and concentration of substrate 13 g/L. In the 5 L fermentor with polypropylene glycol by ISPR, the concentration and productivity of 2-phenylethanol were 6.87 g/L and 0.38 g/(L×h) respectively, compared with no polypropylene glycol extraction, which were improved by 42.2% and 58.3%.

过程与工艺

Chemical Composition of Dust from Stainless Steel Smelting and Existing Forms of Cr and Ni

WEI Fen-rong ZHANG Yan-ling WEI Wen-jie YANG Xiao-gang

. 2011, 11(5):  786-793. 

Asbtract ( )   PDF (831KB) ( )  

Related Articles | Metrics

Chemical compositions, substantial phases, and microscopic morphology of stainless steel dust from TISCO and BaoSteel were analyzed by using several methods, chemical analysis, ICP, XRF, XRD, SEM-EDS and FESEM. Meanwhile, the predominance diagrams of Cr-Fe-C-O and Ni-Fe-C-O systems under various conditions were simulated by using FactSage software. Combining the conditions of stainless steel-making process, it is suggested that in stainless steel dust Cr and Ni exist in the forms of FeCr2O4 and Fe2NiO4, respectively. Furthermore, thermodynamic predictions show that for the four kinds of reduction reagents, C powder, [C] in molten iron, SiC and FeSi, FeCr2O4 is reduced to metallic Cr prior to Cr2O3, and below 1500℃ the reduction ability of these four reagents has the following order: FeSi > SiC > [C] in molten iron > C powder, while above 1500℃, it becomes: [C] > FeSi > C powder > SiC. And for the reduction of Ni, in the cases of FeSi and SiC as reagents, Fe2NiO4 is reduced prior to NiO, while in the cases of [C] and C powder used, the reduction of NiO is easier. Finally, the recovery feasibility of Cr and Ni from stainless steel dust in the form of ferroalloys is discussed.

Direct Reduction Roasting of Refractory Siderite Ore by Using Direct Pelletization

WEI Yu-xia SUN Ti-chang KOU Jue YU Wen

. 2011, 11(5):  794-799. 

Asbtract ( )   PDF (337KB) ( )  

Related Articles | Metrics

The probability and affecting factors of direct reduction roasting and grinding-magnetic separation of pellets made from refractory siderite ore were investigated. Raw ore crashed into less than 2 mm was mixed with certain dosages of organic binder and reductant coal for pelletizing and then the pellets were roasted in a muffle furnace for direct reduction. The influential factors of pelletization, reduction roasting and grinding-magnetic separation were investigated and the optimum conditions identified. The direct reduction iron with 92.76% iron grade and 85.97% recovery was obtained under this condition. The direct reduction of pellets formed by using ball press from less than 2 mm siderite ore powder can produce high iron grade and recovery of direct reduction iron, there appears no gluing, cracking and expanding, therefore the process of pelletization and direct reduction roasting for iron ore is feasible, and can produce direct reduction iron.

Fuel-oriented Utilization of Municipal Sludge

WANG Juan PAN Feng XIAO Chao-lun LI Peng-fei LIU Hui-zhou

. 2011, 11(5):  800-805. 

Asbtract ( )   PDF (256KB) ( )  

Related Articles | Metrics

Experiment was carried out for the resource-oriented utilization of municipal sludge based on the method of RDF (refuse derived fuel). The optimal drying conditions of sludge and the effect of added proportion of pulverized coal on the combustion of sludge were examined. The results showed that the optimal drying time was 4 h and the heating value of dried sludge was about 18 MJ/kg, and the heating value of the sludge was changed with water content and organic content. Besides, the effective ingredients of sludge almost had no change when the drying temperature varied from 105 to 150℃. In addition, the hydrogen content was high in the sludge, so the ignition point of sludge was lower than that of coal.

Effects of Pre-calcination on the Characteristics of Copper-containing Slag and Its Catalytic Activity in Biomass Gasification

WANG Chao HU Jian-hang WANG Hua LIU Hui-li

. 2011, 11(5):  806-811. 

Asbtract ( )   PDF (525KB) ( )  

Related Articles | Metrics

The calcining experiment of copper-containing slag in oxygen atmosphere was carried out. Techniques such as XRD, H2-TPR, BET and SEM analysis were used to examine the effects of pre-calcination on its surface morphology, crystal structure, existence form and distribution of elements. The effect of pre-calcined copper slag on gasification characterization was investigated in a self-build experimental apparatus of biomass gasification. The analysis results indicate that the formation of Fe3O4 and a-Fe2O3 is due to the extrusion of iron from the fayalite in the slag during pre-calcination. With increasing of calcination temperature, prolonging of calcination time and decreasing of particle size, the characteristic peaks of Fe3O4 show a trend of first increasing and then decreasing, while the characteristic peaks of Fe2O3 were enhances. The experimental results of biomass gasification show that the pre-calcined copper slag enhances gas production and quality (H2 19.61%~21.35%, CO 32.55%~36.89%). The increase of catalytic activity of pre-calcined copper slag is due to the formation of Fe3O4 and Fe2O3.

Kinetic Simulation for the Effect of N2 Content on Gas Explosion in an Constant Volume System

JIA Bao-shan LI Yan-hong ZENG Wen LIANG Yun-tao WEN Hai-yan

. 2011, 11(5):  812-817. 

Asbtract ( )   PDF (432KB) ( )  

Related Articles | Metrics

In order to seek the effect of inert gas (N2) on the process of gas explosion in enclosed space, the computational model of gas explosion in enclosed space (constant volume bomb) is built, and the detailed reaction mechanisms (including 53 species and 325 reactions) are adopted. The process is analyzed by applying this model. Through the sensitivity analysis of the reaction mechanisms of gas explosion, the key reactions that affect gas explosion and the formation of catastrophic gases are R32, R53, R98, R155, R156, R158, R161 and R170. And the inhibition mechanism of N2 on gas explosion and formation of catastrophic gases are analyzed. The results show that the gas explosion can produce transient high temperature and high pressure, and the duration of gas explosion is only 0.0001 s. The inert gas (N2) can inhibit the process of gas explosion, and the ignition time of gas explosion is more delayed with increasing of the mole fraction of N2 in the mixed gas. Correspondingly, the explosion intension is weaker (adding 10%, 15% and 20% N2, the gas explosion time delays 0.0009, 0.0013, and 0.0019 s respectively, the pressure decreases about 5.065 kPa progressively, the temperature decreases about 35 K progressively). Furthermore, the inert gas (N2) will inhibit the formations of CO, CO2, NO and NO2. At the same time, with the mole fraction of N2 in the mixed gas increasing, the inhibition will be more distinct.

Property Measurement of [aP4443][Gly]-H2O Binary System and Its Absorption to Carbon Dioxide

WANG Zan-xia FU Li ZHANG Jian-min XU Hui SHANG Ying ZHANG Li MA Qian-qian WANG Zhen-xian

. 2011, 11(5):  818-822. 

Asbtract ( )   PDF (229KB) ( )  

Related Articles | Metrics

The viscosity and conductivity of 3-aminopropyl-tributylphosphonium aminoethanic acid salt ([aP4443][Gly]), (3-aminopropyl)tributylphosphonium L-a-aminopropionic acid salt ([aP4443][Ala]), and (3-aminopropyl)tributylphosphonium L-a-amino-4-methylvaleric acid salt ([aP4443][Val]), and binary system of [aP4443][Gly]-H2O were investigated from 298.15 to 343.15 K respectively. It was found that the viscosity of these pure ionic liquids increased with the alkyl length, and the conductivity decreased. For the binary system with different water mole fractions of 0.00, 0.25, 0.50, 0.75, either increasing water amount or temperature could lead to decrease in viscosity and increase in conductivity. As the mole fraction of water was less than 0.50, the saturated absorption of carbon dioxide kept increasing while decreasing between 0.50 and 0.75, which means that appropriate content of water could improve the absorption behavior.

Investigation on the Growth of TBAB Clathrate Hydrate Crystals

YE Nan ZHANG Peng

. 2011, 11(5):  823-827. 

Asbtract ( )   PDF (309KB) ( )  

Related Articles | Metrics

The formation and growth process of clathrate hydrate crystals in 9%(w) tetra-n-butyl ammonium bromide (TBAB) solution at atmospheric pressure was visually observed, and supercooling was employed as the driving force to investigate the growth characteristics of TBAB clathrate hydrate. At the beginning of the formation, the crystals with high transmittance showed regular columnar shapes, and then grew into the ones with low transmittance and irregular columnar shapes. When the supercooling was 6.0, 8.1 and 9.6 K, the growth time of crystals in the length/width directions was 183 min/140 min, 85 min/65 min, and 70 min/37 min, respectively. Moreover, the waiting time before reaction start was 83 min, 53 min and 55 min, implying that large supercooling could shorten the reaction time and accelerate the formation of TBAB clathrate hydrate. With the increase of supercooling, the amount of hydrate crystal nucleation increased, resulting in the increase of the total contact area between crystals with solution, which is beneficial to the fast formation of TBAB clathrate hydrate.

生化工程专栏

Enantioselective Resolution of Racemic Naproxen by a Lipase from Penicillium expansum

TANG Liang-hua CAI Zhi-xiong SU Min ZHU Ling ZHOU Qiong LU Bo-yan

. 2011, 11(5):  828-833. 

Asbtract ( )   PDF (232KB) ( )  

Related Articles | Metrics

In order to resolute racemic naproxen with high efficiency by the immobilized Penicillium expansum TS414 lipase in organic solvent, the factors affecting the resolution of (R, S)-naproxen by lipase-catalyzed esterification reaction were investigated, including water concentration, temperature, organic solvent, enzyme concentration, structure and concentration of alcohol. And experiments were designed to optimize the conditions of esterification reaction. Under the optimal condition (isooctane as solvent, 2.15 mmol/L ibuprofen, 12 g/L lipase, 34.3 mmol/L 1-propanol, 0.05%(j) water, 200 r/min, 40℃ for 100 h), the conversion rate could reach 48.3%. Thus, Penicillium expansum TS414 lipase could be used as a perfect tool enzyme with high enantioselectivity and had a great potential for commercial applications in the resolution of racemic naproxen and other non-steroidal anti-inflammatory drugs of 2-aryl propionic Acids.

Continuous Transfer Domestication and Associated Domestication of Acidithiobacillus ferrooxidans for Resistance of Uranium and Fluride Ions

WANG Yong-dong DING De-xin LI Guang-yue HU Nan

. 2011, 11(5):  834-839. 

Asbtract ( )   PDF (211KB) ( )  

Related Articles | Metrics

To improve the domestication efficiency of Acidithiobacillus ferrooxidans and obtain strains of Acidithiobacillus ferrooxidans which can endure high concentrations of uranium and fluoride ions, the domestication methods of uranium and fluoride resistance were studied, continuous transfer domestication and associated domestication were put forward. The results showed that the continuous transfer domestication could accelerate the domestication speed and increase the domestication effect, and one strain with the Fe2+ oxidation activity of 7.5 times higher than wild strains in the medium containing 1000 mg/L U6+ was obtained in 96 h. Furthermore, the strains which could tolerate 1500 mg/L U6+ or 80 mg/L F- were obtained using this method. As for the associated domestication, it could acquire the strains with stronger oxidation activity in the medium containing both uranium and fluoride than that of tradition methods. The best results from the group carried through uranium domestication before fluoride domestication, and its Fe2+ oxidation activity was at least 6 times higher than those obtained by the other methods in the medium containing 1000 mg/L U6+ and 80 mg/L F-.

Preparation of Anti-UV Controlled Release Formulation of Avermectin with Carrier of Blue Algae and Its Property

HOU Hong-wei REN Tian-rui YAN Yun-feng WANG Quan-xi XU Wen-ping

. 2011, 11(5):  846-850. 

Asbtract ( )   PDF (368KB) ( )  

Related Articles | Metrics

A major objective of the present work is to develop anti-UV controlled release formulation of avermectin (Av), with utilizing the anti-UV characteristic of blue algae as carrier taken from Dianchi Lake. Av was adsorbed on blue algae powder and then coated with 10% carbomer resin. The blue algae powder and release formulation were characterized by FT-IR, SEM and HPLC. The results show that the adsorptive capacity of Av is 160.81 mg/g in isopropanol at 25℃. The formulation release rate is 51.8% for 20 d in ethanol/water (4:1, j) at 25℃. The controlled release mechanism belongs to Fickian diffusion and matrix erosion. The residual rates of Av with blue algae and alone are 61.0% and 39.0% respectively under UV irradiating. It is improved that blue algae has the function of resistance against UV.

材料工程专栏

Synthesis of SmAlO3 by Polymeric Precursor Method and Its Microwave Dielectric Properties

LI Jia-mao; QIU Tai FAN Chuan-gang; XU Peng

. 2011, 11(5):  851-856. 

Asbtract ( )   PDF (463KB) ( )  

Related Articles | Metrics

SmAlO3 microwave dielectric ceramic powder was successfully synthesized by the polymeric precursor method using EDTA as a chelating agent. The polymeric decomposition mechanism of the precursor, the formation process of SmAlO3 and the properties of the particles were characterized. The results show that the dried gel including EG addition is decomposed completely up to 550℃ and single SmAlO3 phase with orthorhombic perovskite structure is found when the calcining temperature is increased to 800℃. Compared with the conventional solid-state reaction route, the synthesis temperature is sharply decreased from 1400 to 800℃. With the average particle size of about 30 nm, the particles of the as-synthesized powder are uniform and spherical. Using the as-synthesized powder as raw material, the sample sintered at 1550℃ for 2 h possesses the highest relative density of 97.5% and exhibits excellent microwave dielectric properties of relative permittivity er=21, quality factor Qf=77400 GHz and temperature coefficient of resonant frequency τf=-73.2′10-6 ℃-1.

Hydrophilic Modification of Polysulfone Membrane Material by Coupling Grafting of Polyethylene Glycol Monomethylether

DU Rui-kui; GAO Bao-jiao AN Fu-qiang LI Yan-bin

. 2011, 11(5):  857-862. 

Asbtract ( )   PDF (310KB) ( )  

Related Articles | Metrics

In the presence of acid-acceptor Na2CO3, the nucleophilic substitution between chloromethylated polysulfone (CMPSF) and polyethylene glycol monomethyl ether (PEGME) was conducted, and polyethylene glycol (PEG) was coupling-grafted onto the side chains of polysulfone (PSF), so that the graft copolymer PSF-g-PEG was prepared and the hydrophilic modification of polysulfone membrane material realized. The chemical structure of PSF-g-PEG was characterized. The effects of main factors on the coupling graft reaction were examined. The water static contact angle of PSF-g-PEG membrane was determined. The experimental results show that the coupling graft reaction between CMPSF and PEGME can proceed successfully, and the reaction of chloromethyl groups of CMPSF with the hydroxyl end groups of PEGME is a typical SN1 nucleophilic substitution reaction. The polarity of the solvents and the reaction temperature affect the reaction greatly, that is, the stronger the polarity, the greater the grafting degree of PEG. When the dimethyl acetamide with strong polarity is chosen as the solvent, the reaction temperature is 70℃ and reaction time 36 h, grafting degree of PEG is close to 480 g/kg, the contact angle of PSF-g-PEG is greatly reduced from 70o to 35o, so its hydrophility is strongly enhanced.

Preparation and Modification of Low Melting Glass as High Temperature Oxidation-resistant Coatings Binder for Steel Ingots

WANG Shu-hua Lianqi Wei ZHANG Xiao-meng ZHOU Xun YE Shu-feng CHEN Yun-fa

. 2011, 11(5):  863-868. 

Asbtract ( )   PDF (432KB) ( )  

Related Articles | Metrics

The low melting glass used as a binder for high-temperature plain carbon steel was synthesized by P2O5, ZnO, and Na2O, then modified with B2O3, Fe2O3, MnO, CoO, and NiO. The results of DTA and XRD showed that the low-melting glasses could be changed to glass-ceramic with heat treatment. Zinc phosphate was precipitated from the A glass which modified with B2O3 and Fe2O3 after the heat treatment, while nickel phosphate was precipitated from the glass C which modified with B2O3, Fe2O3, MnO, CoO and NiO. The softening temperature of the glass A was 750℃, and 596℃ for glass C, while the glass-ceramic C was increased by 54℃. Softening temperature is an important factor to affect the adhesion property of the low-melting glasses. The modified glass could be used as a binder, which provided a good adhesion for coatings on high temperature steel substrate, and effect of oxidation resistance was 59.24% in the experiment. The reaction mechanism between the coating, glass binder and the iron oxides was also elaborated.

Preparation of Sn-Si-C Composite as Li-ion Battery Anode Material by High Energy Ball Milling and Its Properties

LI Yan-hong LIU Yuan QIU Xin-ping

. 2011, 11(5):  869-874. 

Asbtract ( )   PDF (796KB) ( )  

Related Articles | Metrics

Electrochemically active Sn-Si-C composite was synthesized by high energy ball milling (HEBM) in Ar atmosphere. The so-obtained composite was characterized by X-ray diffraction and field emission scanning electron microscopy. Lithium insertion/extraction characteristics of the composites were examined by constant current charge-discharge and cyclic voltammetry methods. The results show that there is no new alloy generated by HEBM. The composite synthesized by two-step HEBM resulted in initial lithium insertion specific capacity as high as 1224 mA×h/g and higher reversible lithium extraction specific capacity of 855 mA×h/g.

Preparation of Spongy Needle-like Iron Powder and Its Application in Thermal Batteries

LI Yun-wei ZHU Yong-ping

. 2011, 11(5):  875-879. 

Asbtract ( )   PDF (874KB) ( )  

Related Articles | Metrics

The influences of hydrothermal reaction conditions on the morphology of needle-like FeOOH precursor and its particle size were investigated. The appropriate needle-like FeOOH powder was prepared under the hydrothermal conditions of 90℃, 24 h, and molar ratio of FeCl3×6H2O to CO(NH2)2 1:(1.5~4.5). The reducing process has a great effect on the morphology of iron powder. The spongy needle-like iron powder can be prepared at 550℃ under CO reducing atmosphere for 1 h and then H2 for 4 h. Compared with common iron powder, due to its large specific surface area (15.8 m2/g), the ignition sensitivity of spongy needle-like iron powder is higher, its combustion rate faster and quantity of continuance heat greater. The lifetime of thermal batteries can be prolonged for 20% using the iron powder as heating flake, so the spongy needle-like iron powder is an excellent heating material for thermal batteries.

综述

Research Advances in Methanation Catalysts and Their Catalytic Mechanisms

HU Da-cheng GAO Jia-jian JIA Chun-miao PING Yuan JIA Li-hua WANG Ying-li XU Guang-wen GU Fang-na SU Fa-bing

. 2011, 11(5):  880-893. 

Asbtract ( )   PDF (567KB) ( )  

Related Articles | Metrics

Recent advances in methanantion catalysts and catalytic mechanism together with the wide applications of methanation in industry were reviewed, focusing on the effects of catalyst supports, promoters, active components as well as preparation methods on the performance of methanation catalysts. In addition, the catalytic deactivation and mechanism of methanation reaction for carbon oxides are critically analysed based on the reported work. It is pointed out that the temperature rising derived from exothermic methanation reactions in the catalyst bed and carbon deposition on the catalyst surface are the key factors for catalyst deactivation, which can be avoided considering both catalyst and process. Finally, outlook for the future development of methanation catalyst and further investigation of mechanism is provided in light of the current research status, regarding composite support with the high surface area, catalyst modified with the rare earth elements, sulfur- and heat-resistant catalysts, as well as fluidized bed reactor.

Research Advances in Mathematic Modeling of Cross-flow Filtration for Slurry Fischer-Tropsch Synthesis Technology

ZHENG Bo TANG Xiao-jin ZHANG Zhan-zhu ZONG Bao-shou

. 2011, 11(5):  894-900. 

Asbtract ( )   PDF (297KB) ( )  

Related Articles | Metrics

The fouling mechanisms of membrane in the cross-flow filtration for the slurry Fischer-Tropsch synthesis technology (SFTST) were discussed. The research advances of mathematic modeling in cross-flow filtration for SFTST in literature were reviewed in both three-phase and two-phase systems. Based on different resistances, the models can be divided into blocked resistance, cake resistance and combined resistance. It is supposed that the combined resistance in cross-flow filtration for SFTST will be the further research direction.