Table of Content

20 April 2003, Volume 3 Issue 2

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2

Effects of Broth Components on Separation of L-glutamine by Nanofiltration

LI Chun; LIU Yuan-shuai; LI Shu-liang; WANG Xiao-lin; CAO Zhu-an

. 2003, 3(2):  0-0. 

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The effects of salt ions and other components in L-glutamine fermentation broth on the separation of L-glutamine and L-glutamic acid by nanofiltration were investigated and the effects of process operation parameters on permeation properties were studied systematically. The optimum dilution times of fermentation broth and temperature was established. The study also showed that bivalent cations could affect the permeation properties of L-glutamine and L-glutamic acid, and decreased observed rejection of glutamic acid by 8%. Higher concentration of (NH4)2SO4 in broth reduced the observed rejection of L-glutamine and L-glutamic acid and permeation flux greatly, but higher concentration of NH4Cl did not, which demonstrated different repulsion forces of membrane to different ions. When the broth was diluted to 1% for L-glutamine concentration and adjusted to pH=7, other salt ions and residual glucose in broth would not significantly influence L-glutamine separation by nanofiltration due to their low concentrations.

Studies of Heterogeneous Hydrothermal Stripping from Iron-loaded Naphthenic Acid–Alcohol–Kerosen

WANG Xing-yao (王兴尧);KANG Xiao-hong (康晓红);et al.

. 2003, 3(2):  0-0. 

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The technique of hydrothermal stripping from mixed aqueous-organic systems is a promising method for synthesizing oxide ceramic powders for high-performance applications. Some factors influencing heterogeneous hydrothermal stripping with water from iron-loaded organic phase of naphthenic acid–isooctyl alcohol–kerosene, such as initial concentrations of iron and naphthenic acid, concentration of Fe2O3 “seed”, temperature and time, were investigated. Based on the experimental results, the rate equation was established. Nano-ferric oxide powders were obtained by the technique of hydrothermal stripping from the iron-loaded organic phase. The results suggest that the heterogeneous hydrothermal stripping proceeds in 3 steps: adsorption of naphthenic acid dimers and naphthenic complex of iron onto the surface of “seed”, hydrolysis of adsorbed complex of iron, and condensation of hydrolyzed complex. The process activation energy is 115 kJ/mol and the heterogeneous hydrothermal stripping is controlled by a chemical reaction (the hydrolysis of naphthenic complex of iron).

Effect of Shear Stress on Suspension Cultures of Taxus chinensis var. mairei

HAN Rong-bin; SHI Zhong-dong; YANG Wen-li; YUAN Ying-jin

. 2003, 3(2):  0-0. 

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Based on the systematical study of continuous resolution of DL-alanine employing the immobilized Aspergillus oryzae cell, the kinetics of the enzymic reaction was determined. Furthermore, the method of Newton-Raphson was applied to the solution of one-dimension-steady-diffusion model of packed bed for continuous resolution of DL-alanine. The calculated results of the model, with the error less than 10%, were in good agreement with those of experiments. It was demonstrated that the model was reasonable and accurate.

Electrochemical Characteristics of Ti/SnO2+Sb2O3/PbO2 Anode for the Oxidation of Cr3+ in Sulfuric Acid Solution

WANG Ya-qiong; CHEN Chang-ping; TONG Hong-yang; XU Wen-lin

. 2003, 3(2):  0-0. 

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The pseudomonas delafieldii strain R-8 and Rhodococcus erythropolis N1-36 were used to remove the sulfur from hydrogenated diesel oil. Both strains utilize the organic sulfur compounds from diesel oils with approximate activities. Surfactants can increase the desulfurization rate. When agitating rate was 250 r/min with Tween80 present, the strain can remove 72% of the organic sulfur from low sulfur diesel oil (S<300 mg/L) in 72 h. But when sulfur concentration was higher than 1000 mg/L, the sulfur removal rate of diesel oil by strain R-8 is very low.

Properties of Ionic liquids and Its Applications in Catalytic Reactions

WANG Jun-feng; ZHANG Suo-jiang; CHEN Hui-ping; LI Xian; ZHANG Mi-lin

. 2003, 3(2):  0-0. 

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The progresses in the study of ionic liquids (ILs) are critically reviewed, the structure–property relationships and the basic rules are summarized. The applications of ILs in some catalytic reactions are itemized, with special attention given to metal-catalytic and bio-catalytic reactions and reaction–separation coupling processes. High activity and selectivity of enzymes are found in trace water containing or non-aqueous ILs, which may bring the breakthrough in the synthesis and catalysis. Supercritical CO2/ILs and IL/water/organic phase provide new ways for reaction– separation coupling, which may have great effects on green chemistry.

Preparation of Monodisperse Silica Ultramicrons

WANG Ling-lingl;FANG Xiao-longl;TANG Fang-qiong;YANG Chuan-fangl; LIU Hui-Zhoul

. 2003, 3(2):  0-0. 

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The main factors that affect the leaching rate of potassium in potash feldspar were studied. It is shown that the best reaction conditions are reaction temperature of 890~950oC, size of potash feldspar ores below 0.208 mm, and the weight ratio of sodium chloride to potash feldspar ores being 1. The study showed that the leaching process is controlled by the internal ionic diffusion of Na+ and K+ in potash feldspar. The relations between diffusion coefficient and reaction temperature is expressed by the Arrhenius formula: Deff=D0exp(-–Ea/RT), with Ea = 81.42 kJ/mol, D0=0.324 mm2/h.

Plasmid Stability in High Cell Density Cultures of E.coli HB101(pBR322)

YU Guo-ce; JIAO Rui-shen; WANG Ji-cheng; WANG Shu-qing

. 2003, 3(2):  0-0. 

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The steelmaking workshop is an important subsystem of steel manufacturing process system, the complexity of production process and difficulty of process control are the most concentrated expression on the multidimensional mass flow control in steel manufacturing process. Optimization and control in steelmaking zone is the key point of operation control in steel manufacturing process system. On the basis of summarizing research on mass flow control in several steelmaking workshops, the theoretical approach has been done for steelmaking system operating and controlling. The relationship between logic and realization for optimized running of steelmaking workshop has been deduced, and some supplement to control strategy of steelmaking workshop has also been made. Levels and guiding strategy of system optimized running have been expounded.

Solvent-containing Preparative Electrophoresis of Proteins

LUO Jian; LIU Zheng

. 2003, 3(2):  0-0. 

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Aimed at directly mine operation conditions, WC particle/grey iron and low-chromium alloy white iron matrix composites were manufactured, and their anti-erosive wear properties were investigated against high-chromium cast iron. Results showed that the erosive wear resistance of composites with different metal matrix materials was better than that of high-Cr cast iron, and that of high-carbon and low-Cr white iron matrix was the best.

Effect of Particle Size on Products from Flash Pyrolysis of Huolinhe Lignite in a Spouted-entrained Bed

CUI Li-jie; YAO Jian-zhong; LIN Wei-gang

. 2003, 3(2):  0-0. 

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k–e turbulence model and Ergun equation is applied to simulate the gas-flow behaviour in a Z-path-moving bed. Especially, the effect of the angle of the inclined perforated plates was investigated. The simulation result was agreed well with the experimental data, which demonstrated the reliability of the model. The simulation disclosed that, in a Z-path moving bed, with the enlargement of angle of the inclined perforated plates, the pressure drop reduced and the fact that gas flow towards the high end of the above perforated plate was enhanced.

Hydrothermal Modification of Mg(OH)2 Particles in NaOH Solution

XIANG Lan; JIN Yong-cheng; JIN Yong

. 2003, 3(2):  0-0. 

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The hydrothermal modification behavior of Mg(OH)2 particles in aqueous NaOH solution was investigated, with focus on the influence of NaOH concentration on the morphology, crystalline structure and dispersion properties of the hydrothermal products. Regular hexagonal plates of Mg(OH)2 with uniform size and smaller specific area were formed after hydrothermal treatment. The dispersion properties of the hydrothermal products were improved owing to the alteration of growth direction for Mg(OH)2 crystals, resulting in the increase of I(001)/I(101). Under the experimental conditions (1.5 mol/L of NaOH), the increase of NaOH concentration is favorable to the hydrothermal modification of Mg(OH)2 particles. Thermodynamic calculation indicated that in the Mg(OH)2– NaOH-H2O system, the concentration of OH- ions was much higher than that of soluble Mg-bearing species [Mg(OH)2(aq), MgOH+ and Mg2+]. The improvement for the hydrothermal modification of Mg(OH)2 in the comparatively concentrated NaOH solution may be attributed to the increase of OH- concentration.

Amino Acid Metabolism of Vero Cells in Batch Culture

GAO Hong-liang; CONG Wei; OUYANG Fan

. 2003, 3(2):  0-0. 

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Bioleaching of Ni–Cu sulfide concentrate with Acidianus brierleyi was investigated in shake flasks. The results confirmed that the most favorable conditions for Ni and Cu simultaneous dissolution were pH 1.2~1.6, inoculum 10%~20%, lower pulp density and the particle size less than 48 μm. Under the condition of 68oC, initial pH 1.6, inoculum 10%, pulp density 5%, Ni and Cu was leached 99.78% and 86.30% respectively after 4.5 d; the dissolution of Ni and Cu could be enhanced by the addition of 50~200 mg/L yeast extract and 1~5 g/L Fe3+.

Catalytic Synthesis and Separation of Ethyl–glucoside

TU Mao-bing; WEI Dong-zhi

. 2003, 3(2):  0-0. 

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Research was undertaken to produce ethyl-glucoside by catalysis of ion exchange resin in heterogeneous systems and to determine effects of catalyst type, size, stirring speed and temperature on conversion. 89% of conversion was obtained under the conditions: temperature 78oC, ratio of resin to glucose 1:1, reaction time 20 h. The effective separation of glucoside from glucose was achieved by column chromatography.

Minimum Spouting Velocity of Multi-component Particle Mixtures in a Slot-rectangular Spouted Bed

WANG Bao-qun; LUO Bao-lin

. 2003, 3(2):  0-0. 

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This paper is focused on the application of the portable X-ray photography technique to measurement of the radial and axial profiles of solid concentration in a gas–solids riser, a pilot-plant-scale downer, and a nano- agglomerate fluidized bed of carbon nanotubes. Twenty to thirty images with 100~200 ns X-ray pulses were processed to get a time-averaged concentration profile. Results show that this technique is a promising non-intrusive method to get time-averaged solid concentration profiles in gas–solids two phase flow systems.

Effect of Nutrient Conditions on the Growth of Botryococcus braunii

WANG Jun; YANG Su-ling; CONG Wei; CAI Zhao-ling

. 2003, 3(2):  0-0. 

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Extracting penicillin by aliphatic alcohols was studied in this work. The aliphatic alcohols were more efficient than butyl acetate in extracting penicillin at pH=4. Mixtures of aliphatic alcohol and butyl acetate showed strong coordinated extraction effect. Aliphatic alcohols with branched chain had a little stronger ability to extracting penicillin than straight chain alcohols with the same number of carbon atoms, and water content in organic phase was reduced at the same time. Results of FT–IR indicated, that with adding of butyl acetate, hydroxyl group spectra of aliphatic alcohol became wider and shifted to higher wavenumber. It suggested that butyl acetate molecular blocked forming of aliphatic alcohol congeries, which made hydroxyl group more active. It was suggested by FT-Raman that penicillin molecule entered alcohol phase in inverse microemulsion. The branched chain of alcohols made the system more orderly and polar, which was also favorable to extraction of penicillin.

Application of Stoichiometric Displacement Model for Retention to the Chromatographic Separation by Molecular Imprinting Polymer

SUN Rui-feng; LUO Hui; SUI Hong-yan; SHEN Zhong-yao

. 2003, 3(2):  0-0. 

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In the presence of template molecule of N-Boc-L-Tryptophan, molecular imprinting polymers (MIPs) were synthesized and evaluated by liquid chromatography. The results showed that the racemic N-Boc-Tryptophan was efficiently separated. Interaction of template molecule and stationary phase or mobile phase was analyzed with the stoichiometric displacement model for retention (SDM-R). It was showed that when absorption occurred between template molecule and MIPs, the molecule number of the displacing agent (isopropyl alcohol) released from the surface of the stationary phase was 1.2 fold that of its enantiomer, and the molecule number of the displacing agent released from a solute molecule was 1.5 fold that of its enantiomer. All these results indicated that the molecule recognition depended mainly on the structure between template molecule and MIPs.

Rational Utilization of Residual Coal Gas in Iron Steel Plant

WANG Li-xin; LI Xin; XU Zhi-hong; YANG Zhang-yuan

. 2003, 3(2):  0-0. 

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There is currently large amount of residual coal gas in iron-steel plants which should be used in the future, otherwise it will cause energy loss and environmental pollution. It is suggested in this paper that the coal gas can be used to produce electricity or chemicals. The situation is also discussed when new technologies such as smelting reduction process and continuous casting process are adopted.

Variation of Surface Tension of Sodium Aluminate Solution with Electrolytic Microstructure

WANG Ya-jing; ZHAI Yu-chun; TIAN Yan-wen; HAN Yue-xin; LIU Lian-li

. 2003, 3(2):  0-0. 

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In the present study, by solving turbulent flow of molten metal and inclusion trajectory, the rising velocity of inclusion in molten steel was calculated, and the behavior of moving inclusion in the slab continuous casting mould was studied numerically. The predicted result was validated experimentally. The numerical results show that the larger the diameter of the inclusion, the greater the effect of the buoyancy, the shorter the penetration depth, the less the residence time in the mould, and the higher removal rate of the inclusion. The vertical depth of the continuous