The Chinese Journal of Process Engineering

Process Engineering

Mooson KWAUK YANG Ji-ke

. 2008, 8(4): 625-635.

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This paper, written 49 years ago as an in-house document, relates the basic concepts of process engineering and how to organize process development including details at various stages. It is being published as a historical document in commemoration of the 50th anniversary of the Institute of Process Engineering, Chinese Academy of Sciences.

Discussion on Basic Theories for Process Engineering

LI Hong-zhong

. 2008, 8(4): 635-644.

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The principles and knowledge of chemical engineering has been applied into many processing fields such as metallurgy, materials, energy source, environment, bioengineering and so on. Therefore the chemical engineering could be renamed as process engineering. The present theories on heat transfer, mass transfer, momentum transfer, and chemical reaction for chemical engineering are still the basic theories for process engineering. However, it is inevitable and possible to produce new basic theories for process engineering. Along with the fast development of computer technology and measurement instruments, the research range of process engineering is extended to cover from observation and prediction of the micro-scale structure and interface to the system integration of the macro-scale equipment and plant, which refers to the structure, interface, and multi-scale issues. The methodology of averaging, which neglects the influences of the heterogeneous multi-scale structure and interface, should be replaced by the multi-scale methodology. In addition the shortage of energy resource and natural resources, the pollution of the environment have become the challenging problems facing to the mankind. The green operation and optimal integration of process engineering have become focal points of researchers. The principles and methods on the structure, interface, multi-scale, green operation, and optimal integration of process engineering should be the contents of the new basic theories for process engineering.

Knowledge on Particle Swarm: The Important Basis for Multi-scale Numerical Simulation of Multiphase Flows

MAO Zai-sha

. 2008, 8(4): 645-659.

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Numerical simulation of multiphase flows in processing equipment in process industry with two-fluid model and Eulerian-Lagrangian approach requires the constitutive equations describing the interactions between the dispersed phase of high concentration and the continuous phase. The status of research on the forces on solid and fluid particles and the topics remaining to be tackled are reviewed. As compared with the knowledge on drag of single solid particles, study on particle swarms and on other forces is not sufficient to meet the needs of numerical simulation of multiphase flows. Thus, thorough study on the particle swarms and clusters becomes the key to accurate multi-scale simulation of multiphase flows. Besides, the development of efficient algorithm dealing with the simultaneous non-uniformity on equipment and mesoscopic scales is recognized as an important issue to be resolved.

Vision of Nano/Micro-structured Interfacial Phenomenon Prediction and Control in Chemical Process Engineering

LIU Hui-zhou GUO Chen CHANG Zhi-dong YANG Chao LI Hong-zhong CHEN Jia-yong

. 2008, 8(4): 660-666.

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This review highlights recent advances in research of nano/micro-structured interface phenomena in chemistry and chemical process engineering. Through analysis and discussion of a few typical examples, it presents that nano/micro-structured interface phenomenon is not only the hot spot of research in both of chemistry and chemical engineering areas, but also the basis of new knowledge of mass transfer processes. Application of quantitative structure-performance relationship and models for the prediction and control of nano/micro-structured interfacial phenomena of chemical engineering process from molecular structure is also discussed. Along with establishment of relationships of nano/micro-structured interfacial phenomenon and "mass transfer, heat transfer, momentum transfer and reaction engineering", it is possible to build scientific theory of design, scale-up and control in process engineering, therefore chemical engineering science will enter into a new milestone.

Process Control in Bioenergy Preparation via Biochemical Routes

WANG Yu-chun ZENG Jian-li

. 2008, 8(4): 667-675.

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The progress of process regulation in the bioenergy preparation via biochemical routes was reviewed. The biochemical processes of preparing biodiesel, ethanol and hydrogen were easily influenced by substrates, inhibitors, reaction conditions, etc. A number of regulation methods, such as pretreating substrates, batch feeding substrates, immobilizing enzyme and cell, removing of inhibitors, co-culture, were adopted to improve the reaction efficiency in bioenergy preparation. Through the summary of existing regulations, it was pointed out that based on complete understanding on the reaction mechanism and mutual relationship among the molecules, cells and bacterial group, whole-process regulation and multi-scale regulation would be the main research direction in the process regulation.

Research Progress on Key Process and Intergrated Eco-industrial Chains of Biobased Products?Proposal of Biobased Product Process Engineering

CHEN Hong-zhang WANG Lan

. 2008, 8(4): 676-681.

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Bioprocessing of biomass to bioenergy, biomaterials and biochemicals has been becoming a hot topic internationally. Presently, the main problem for bio-products preparation is lack of effective components fractionation technology and integrated conversion process. Based on cellulosic feedstock characteristic and key issues related to conversion process and product engineering, the concept of biobased product process engineering is proposed. In addition to giving a novel fractionation-conversion system of biomass, this paper also introduces four key technical platforms, namely unpolluted steam explosion and components fractionation, purified microbial solid-state fermentation, solid-phase hydrolysis coupled with liquid-phase ethanol fermentation, and recycling membrane hydrolysis-fermentation. The fractionation-conversion system will provide R&D approach and technical support for the whole biomass utilization and bio-products eco-industrialization.

Techniques for Utilization of Heavy Hydrocarbons: Simulation Study on the Integrated Gasification-Pyrolysis Process for Heavy Hydrocarbons

WEN Hao XU Zhi-hong WANG Shao-feng ZHAO Yue-hong

. 2008, 8(4): 682-689.

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China is such a developing country of lacking petroleum resource, its petroleum supply depends highly upon the world petroleum market. Developing the techniques for heavy hydrocarbons utilization is becoming a critical task to the energy and petrochemical industries in China, because of the gradual decrease of light crude oil and the increasing demand on light petro-products. Delayed coking, visbreaking, catalytic cracking and hydroconversion are primary technologies at present, while the pyrolysis and gasification present potentials in heavy hydrocarbons processing. An integrated gasification-pyrolysis process is proposed in this paper, in order to produce the syngas and light olefins by gasification and pyrolysis of heavy hydrocarbons with heat supply by the combustion of coke produced during pyrolysis. Simulation studies show that the production of syngas and light olefins will be achieved with controlling the temperature of gasification-pyrolysis process by adjusting the feeds of O2 and steam, even at the condition without fuel feeding. The maximum composition of light olefins can be found in product stream in the case of short residence time.

Energy Strategy and Process Engineering

XU Zhi-hong WEN Hao ZHAO Yue-hong

. 2008, 8(4): 690-694.

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From the early period of last century, people entered into the mineral energy age. Starting from this century, the prices of petroleum and natural gas become unstable, in fact we are brought into the co-existence age of three kinds of energy, mineral energy, sustainable energy and nuclear energy, in which people are urged to carry out the study of new energy process engineering. The nuclear fusion age might be started at the last phase of this century or early period of the next century.

Utilization of High Value-added Products Based on Crude Glycerol from Biodiesel Process

XU Yun-zhen OU Xian-jin GUO Ni-ni LIU De-hua

. 2008, 8(4): 695-702.

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10% crude glycerol will be produced during the production of biodiesel. Therefore, in the industrialization progress of biodiesel, the effective utilization of crude glycerol becomes a major issue all over the world. The glycerol can be transformed into many products with highly added value, such as 1,3-propanediol, epichlorohydrin, lactic acid, polyhydroxyalkanoate, hydrogen, dihydroxyacetone and propylene glycerol, all of which show good market prospect. The processes of 1,3-propanediol fermentation and chemical epichlorohydrin production are being applied in a large scale, whereas other processes are still in the stage of laboratory research. Here we will present the technique and development status about the recycle of crude glycerol.

Numerical Simulation on Combustion Characteristics of Low NOx Swirling Coal-fired Furnace

WANG Xiao-han ZHU Bo ZHAO Dai-qing JIANG Li-qiao YANG Wei-bin

. 2008, 8(4): 703-708.

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Based on the previous studies of cold experiment and modeling, the numerical simulation of combustion characteristics of low NOx swirling coal-fired furnace was carried on using the CFD software, STAR-CD3.15. Two zones, swirling reductive zone and burnout zone, appear obviously in the furnace with different features. Coal particles swirl and break up continuously in the reducing zone, which results in low temperature and even temperature distribution. While in the burnout zone, the local stoichiometric ratio is higher than that in the reducing zone, which makes the temperature high and is helpful to particle burnout. The simulation results show that the furnace is able to operate stably with low NOx emission for coal particles with the sizes less than 0.5 mm. Furthermore, the furnace design is optimized by modification of primary air injection. Using the uniform multi-inlet instead of the single inlet, the particle residence time in the swirling reducing zone can be increased. The structural change can prevent the particles from escaping and improve the combustion efficiency as well as decrease the NOx emission sharply. With the injection improved, the NOx emission is only 8.99′10-5 kg/kg (118 mg/Nm3), which is much less than that of the national NOx emission standard for solid-bath furnace, 650 mg/Nm3.

Measurement of Stirring Power and Mass Transfer by a Side-entering Gas-Liquid Agitator

DOU Rong-li HUANG Xiong-bin WANG Xin CHEN Zhi-sheng

. 2008, 8(4): 709-713.

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The influences of agitator number and superficial gas velocity on the power number were studied in a tank of f2000 mm′4200 mm with side-entering agitators. The results indicate that compared to a conventional agitated tank Reynolds number (104), a constant power number is obtained at a higher Reynolds number (3′105) and the effect of gas phase on power consumption decrease is 28% of conventional agitated tank. The gas-liquid mass transfer coefficients KLa with jet and network gas distributing devices have been investigated under same power number, and the results show that a jet gas distributing devices is about 3 times better performance of mass transfer than network gas distributing devices. The formula of mass transfer coefficient of jet gas distributing devices has been obtained as KLaμ(P/VL)0.161VG1.125, and that of network gas distributing devices is KLaμVG1.778. The investigation results provide reference to design of side-entering agitated tanks.

Experimental Study on Turbulence Properties in a Kenics Static Mixer

WU Jian-hua ZHANG Chun-mei JIN Dan SUN Dong GONG Bin

. 2008, 8(4): 714-718.

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The three-dimensional pulsating velocity distribution of fluid in a Kenics static mixer was measured by using laser Doppler velocimetry. The analysis of experimental data shows that the influences of inlet flow rate on the distributions of pulsating velocity, turbulence intensity, and Reynolds stress are less. But the radial component, axial component, and circumferential component of pulsating velocity are enhanced with inlet flow rate increasing, especially for its radial component. When Reynolds number is above 6400, square root mean of pulsating velocity, radial turbulence intensity, turbulence kinetic energy increase distinctively with the increase of inlet flow rate, Reynolds stress is enhanced with the flow rate increasing, and more significant incremental change is seen for the components of txy and txz than that for tyz, txy increases rapidly when Reynolds number is above 6400.

Extraction of Capsaicin from Leaching Solution of Hot Pepper Powder

DENG Xiong CHANG Zhi-dong LEI Chao LIU Hui-zhou

. 2008, 8(4): 719-724.

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The process of solvent extraction and purification of capsaicin from leaching solution of hot pepper powder was studied using commercial dry hot pepper as raw material, 95%(w) ethanol as leaching solvent, and n-hexane and n-butyl acetate as extractants. The effects of pH value and phase ratio on the yield of capsaicin both in simulation system and real system were investigated. The results showed that acidification extraction was the control step. Yield of capsaicin in simulation system could reach above 90% at pH 11 and phase ratio 7:1 when the n-butyl acetate was used. When n-butyl acetate was used as extractant, concentration ratio of capsaicin could be increased. The trend of extraction yield in real system was similar to that in simulation system, but nearly 20% capsaicin could not be extracted. When amount of hot pepper powder was 50 g, yield of capsaicin with 250 mL 95% ethanol twice leaching could be 97.0%. Leaching solution was concentrated, dissolved in sodium hydroxide solution, and extracted by n-butyl acetate at pH value 13 and phase ratio O/W 1:1, then pH value of aqueous phase was adjusted to less than 11 with hydrochloride, the yield of capsaicin with n-butyl acetate extraction at phase ratio 1:5 could achieve 80% of leached amount.

Leaching of Silver from Boorchi Ag-Pb Ore in Mongolia with

Nyamdelger SHIRCHINNAMJIL FANG Zhao-heng YANG Chao

. 2008, 8(4): 725-730.

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A hydrometallurgical process to extract silver from the silver-lead ore in Boorchi, Mongolia by using thiourea leaching solution is studied in this work. Through the observation of optical and scanning electron microscopes, and energy spectral analysis, it is determined that 5 kinds of silver minerals exist in the ore, including argentite, Ag-tetrahedrite, Ag-Zn-Sb-tetrahedrite, freibergite and acanthite. The experimental results of direct thiourea leaching of the ore show that 56%~60% of silver is leached. The main reason for the low leaching rate is due to silver minerals enveloped in galena and other minerals, even though the ore is ground to the particle size of 75 mm. When the ore is pretreated with ammonium carbonate solution under oxidation, the experimental results of thiourea leaching show that the leaching rate of silver increases to near 75% with the pretreatment. Based on the leaching experiments, a principle hydrometallurgical technological route to extract silver from the Ag-Pb ore is proposed.

Leaching of Policosanol from Sugar Refinery Residue

JU Na CHANG Zhi-dong HUANG Min-zhang XIAO Bo LIU Hui-zhou

. 2008, 8(4): 731-735.

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Leaching of policosanol from sugar refinery residue with ammonia as the first solvent and petroleum ether as the second solvent was studied. The effects of leaching temperature, leaching time and concentration of solvent on leaching rate of policosanol were investigated and optimized. The results showed that the leaching rate of policosanol approached 90% when 25%~28% ammonia was used as the first solvent to leach the original residue for 3 h under 90℃, and petroleum ether was used as the second solvent to leach the residue of the first step for 2 h under 60℃.

Pervaporation Performance of Poly(acrylic acid)-Poly(vinyl alcohol) Blend Membrane for Separation of Methanol-Dimethyl Carbonate Azeotrope

LI Ping WANG Lu-ying CHOU Shu-ren LI Ji-ding

. 2008, 8(4): 736-740.

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Poly(acrylic acid)-poly(vinyl alcohol) (PAA-PVA) blend membrane was prepared by coating method for separating methanol -dimethyl carbonate (MeOH-DMC) azeotrope by pervaporation, and the influences of mass ratio of PAA to PVA, and heat treatment conditions on pervaporation performance of the membrane were investigated. The experimented results of pervaporation showed that as the heat treatment time and temperature increased, the separation factor of MeOH increased first and then decreased, but the flux decreased gradually, as PAA/PVA ratio increased, the separation factor increased first and then decreased, but the flux decreased first and then increased. For separating MeOH-DMC azeotrope of 70%(w) MeOH at 70℃, the PAA-PVA blend membrane with a mass ratio of PAA to PVA at 7/3 and heated at 150℃ for 60 min had the highest selectivity, the separation factor of MeOH was 9.5 (MeOH in the permeate side of 95.5%, w), the flux 360 g/(m2×h).

Extraction of Au(I) from Alkaline Cyanide Solution with Guanidine Hydrochloride-Hexadecylpyridine Bromide

PAN Lu WANG Feng-wu ZHANG Zu-de

. 2008, 8(4): 741-745.

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The effects of concentrations of guanidine hydrochloride (GCl) and hexadecylpyridine bromide (RBr) served as extracting reagents on the performance of Au(I) extraction from cyanide solution were investigated when n-pentanol acted as diluting reagent. The synergic extraction effects of Au(I) were examined with GCl and RBr at the total concentration of 0.06 mol/L. The results show that synergic extraction effects are obvious within the whole concentration composition range of GCl-RBr (synergic extraction coefficient R>1), and when GCl and RBr concentrations are 0.05 and 0.01 mol/L, the synergic extracting coefficient is 13.98. The effects of equilibrium time, phase ratio O/A, pH value and Au(I) concentration in the aqueous phase on the extraction rate of Au(I) were investigated by the synergic extraction system. The possible extraction mechanism of Au(I) with GCl and RBr was analysed. Au(I) was stripped respectively by Na2SO3 solution and KSCN solution, and KSCN was more excellent than Na2SO3 on stripping of Au(I). The stripping rate of Au(I) was 98.5% when KSCN concentration was 12 g/L and stripping time 30 min and phase ratio A/O 1.

Characteristics of Natural Gas Hydrate Growth on the Pendant Water Droplet

ZHOGN Dong-liang LIU Dao-ping WU Zhi-min ZHANG Liang WU De-hu

. 2008, 8(4): 746-750.

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Aiming at the water spray formation of natural gas hydrate, a set of experimental apparatus was designed and built to study the natural gas hydrate formation on the pendant water droplet, the growth morphology of gas hydrate on the pendant water droplet under different pressures and temperatures was observed. The growth model of hydrate film on the surface of water droplet was established, and the effects of driving force, subcooling, hydration reaction rate, gas diffusivity and sodium dodecyl sulfate (SDS) concentration on the hydrate film growth were investigated. The results showed that the growth rate of hydrate film increased with the increase of subcooling degree, the measured growth rate was between 0.24 and 0.39 mm/s. The hydrate growth was inside diffusion control, the activation energy of natural gas hydrate was 13.01 kJ/mol. The reaction rate constant on the reaction interface had the maximum value of 0.0027 m/s with SDS concentration in 550 mg/L.

Catalytic Oxidation of Phenol in Waste Water with High Concentration by Fe-ZSM-5 Zeolite Catalyst

Lu Shu-xiang WEI Jia HU Yang GUO Li-mei DENG Yu WU Wen-lie

. 2008, 8(4): 751-755.

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The Fe-ZSM-5 zeolite catalyst was prepared by Fe(NO3)3 and H-ZSM-5 zeolite with various Si/Al ratios. The effects of aqueous solution pH, reaction temperature, amounts of catalyst and H2O2 used, reaction time, stirring speed and Si/Al ratio on the degradation rate of phenol in waste water with high concentration were investigated, respectively. The results show that the degradation rate of phenol is 99% and removal rate of COD 88% under the optimal conditions. The performance of catalyst is affected obviously by the Si/Al ratio of the catalyst. The catalytic activity of Fe-ZSM-5 zeolite is not decreased after being used repeatedly. Compared with Fenton system, the concentration of iron ion in the treated solution is below 1′10-6 g/L by Fe-ZSM-5 catalyst, and the possibility of induced pollution caused by the metal ions in the solution is avoided.

Slagging Characteristics of Molten Ash on Corundum during Pulverized Coal Combustion

HE Jin-qiao SHI Zhang-ming CHEN Dong-lin YAN Xiao-zhong

. 2008, 8(4): 756-760.

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In order to study the slagging characteristics of corundum refractory materials during pulverized coal stream combustion, the slag samples of pulverized coal stream combustion experiments were investigated by optic microscope and X-ray diffraction. The morphology and crystallization of slag samples, and the sintering characteristics between ash components and corundum at high temperatures were studied. The results show that the released CO during pulverized coal stream combustion makes coke granules surface combust in deoxidization atmosphere, which lowers the ash melting temperature and strengthens the interaction between molten ash and corundum; Al2O3 in ash does not improve the crystallinity of slagging samples, but Cr2O3 in refractory board and Fe2O3, CaO, TiO2 in ash enhance the crystallinity; the crystallinity preferably reflects the viscidity action between ash dregs and corundum combustion liners, in coke granules catching fire and combusting region, the crystallinity reduces to the minimum, which is about 49% for coal sample I and about 32% for coal sample II.

Dominant Bacteria in Bioleaching System of Low-grade Copper Sulphide Ore Consisting Mainly of Chalcopyrite

ZOU Ping ZHANG Wen-bin LIN Lian-bin ZHANG Lan-lan LEI Ting

. 2008, 8(4): 761-767.

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In order to find out the reaction mechanism of bacteria with chalcopyrite, the dominant bacteria in a bioleaching system of low-grade copper sulphide ore consisting mainly of chalcopyrite were investigated. By using a 9K culture medium, 14 pure strains of mesophiles were isolated from leaching pulp of the ore. Copper leaching rates for these pure strains were all lower than those before isolation, indicating that there exists a synergistic effect among these strains of the domestic bacteria in the bioleaching process of the ore. By the sequence analysis of 16S rDNA, strains YK8, YK12 and YK14, which were randomly sampled from the 14 strains, were highly relative to Acidithiobacillus ferrooxidans, with 99% sequence similarity, though they were very different in oxidation ability from each other. The three strains were identified as the species of Acidithiobacillus ferrooxidans, exhibiting the diversity of singleness of the bacterium community. The fact that the bioleaching system was dominated by the species of Acidithiobacillus ferrooxidans indicates that the mechanism of bacterial oxidation is mainly direct reaction. There were marked differences in Fe2+ oxidation rate of various pure strains and notable changes in copper leaching rate for various bacteria induced by different culture media containing different energy sources.

Purification and Characterization of Three Alkaline Endopolygalacturonases from a Newly Isolated Bacillus gibsonii

LI Zu-ming JIN Bo ZHANG Hong-xun BAI Zhi-hui XUE Wen-tong LI Hong-yu

. 2008, 8(4): 768-773.

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A newly isolated Bacillus gibsonii, designated as S-2 (CGMCC1215), was cultivated for production of alkaline pectinases utilizing sugar beet pulp as growth substrate. Purification of three alkaline endopolygalacturonases (endoPGs) from the crude pectinases extract was carried out by ultra-filtration, ammonium sulphate fractionation and ion-exchange chromatography, and their enzyme activities characterized. The three purified alkaline endoPGs, designated as S-I, S-II, and S-III, had a molecular weight about 38 kDa as determined by SDS-PAGE. The Km value and optimal temperature for optimal enzyme activities of S-I, S-II and S-III were 1.2 mg/mL and 60℃, 0.9 mg/mL and 55℃, 1.1 mg/mL and 60℃, respectively. Their best performances were given at an optimal pH 10.5, and sodium polygalacturonate was found to be the best substrate. The isoelectric points of S-I, S-II and S-III were 5.4, 7.4, and 8.2, respectively. Surfactants of Tween-80 and Tween-20 and metal ions such as Mg2+ and Ca2+ stimulated the activity of S-I, S-II and S-III, whereas S-III was inhibited by Ca2+, and Mn2+ and Zn2+ ions inhibited the activity of the three enzymes.

Extraction of Artemisinin from Artemisia annual L. with 1-Ethyl-3-methylimidazolium Bromide Enhanced by Ultrasonic Wave

XIA Yu-jie ZENG Jian-li ZHAO Bing

. 2008, 8(4): 774-778.

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Extraction of artemisinin from Artemisia annual L. using ionic liquid [emim]Br (1-ethyl-3-methylimidazolium bromide)- water system enhanced by ultrasonic wave was investigated. Through orthogonal and single factor experiments, the results showed that the sequence of notability of artemisinin extraction factors was: liquid-to-solid ratio > extraction time > extraction temperature > ultrasonic wave power > duty ratio. Comprehensively considering single factor experiments and production cost, the optimum extraction conditions were obtained as Artemisia annual L. granularity at 0.38 mm, liquid-to-solid ratio 50 mL/g, extraction time 30 min, extraction temperature 20℃, ultrasonic wave power 600 W and duty ratio 1.6 s/0.4 s. Under the above conditions, the extraction amount of artemisinin was 4.37 mg/g and the extraction rate 97%.

Removal of Klebsiella pneumoniae Cells from 2, 3-Butanediol Fermentation Broth by Flocculation and Reuse of Cells in Flocs

ZHANG Jiang-hong SUN Li-hui XIU Zhi-long

. 2008, 8(4): 779-783.

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The pretreatment of 2,3-butanediol fermentation broth by chitosan flocculation was investigated. Using sodium alginate as coagulant, the effects of chitosan molecular weight, chitosan dosage, coagulant dosage, pH and turbidity time on the flocculation of fermentation broth were investigated, respectively. The performance was evaluated by flocculation ratio. According to the results, the optimum flocculation conditions for Klebsiella pneumoniae cells were as follows: 0.375 g/L of chitoson with 40 kDa molecular weight, 0.250 g/L of sodium alginate, pH 5.0, 30 min of stirring time and 1 h of settlement time. The flocculation rate reached 98%, the retained ratio of 2,3-butanediol reached 99%, and the supernatant in the broth was clear. After flocculation the cells of Klebsiella pneumoniae in the flocs grew well (OD 13.5) and were used repeatedly.

Construction of an Efficient Cofactor-regeneration System in Rhodococcus erythropolis LSSE8-1

LI Hai-bo XING Jian-min XIONG Xiao-chao LIU Hui-zhou

. 2008, 8(4): 784-788.

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The aim of this study was to develop a new biocatalyst with high NADH regeneration, which was helpful to increase desulfurizatin activity. Formate dehydrogenase gene (fdh) was amplified from Rhodococcus RHA1 and then introduced into an specific desulfurization bacterium, Rhodococcus erythropolis LSSE8-1, using an E. coli-R. erythropolis shuttle vector pBS306. TTC reaction showed that the dehydrogenase activity of LSSE8-1-FDH (OD496) was 0.464, the dehydrogenase activity of LSSE8-1 (OD496) was 0.353, and the dehydrogenase activity increased 31%. Recombinant strain showed a moderately faster growth rate in 25 mmol/L sodium formate solution. Desulfurization of DBT in the oil-aqueous two phases system by LSSE8-1 and LSSE8-1-FDH was conducted respectively. Compared with the orginal strain LSSE8-1, the recombinant strain LSSE8-1-FDH had an increase of 12.5% in desulfurizing activity, 4 h in desulfurizing time, and total desulfuriztion capacity increased 20%.

Expression of cTnI Specific Antigen Sites and Antibodies Detection

SHI Li-li LI Qiang YUAN Qi-peng

. 2008, 8(4): 789-793.

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Two specific epitope sites of human cardiac Troponin I (hcTnI), 38aa~52aa and 87aa~97aa, which can stably exist in the blood serum of acute myocardial infarction (AMI) patients, were selected as objective gene sequences and isolated by 5 lysines with low immunogenicity. Two specific epitopes and lysines constituted AA gene sequence. Plasmid pMAL-Antigen consisting of 5AAs after maltose binding protein (MBP) was constructed by two restriction endonucleases, BamHI and BgLII. The pMAL-Antigen plasmid was diverted into E. coli BL21(DE3), and MBP-Antigen fusion protein was induced by 1.0 mmol/L IPTG in E. coli BL21(DE3). The MBP-Antigen fusion protein was purified by Amylose-resin. The result showed that protein antigen of MBP-Antigen fusion protein was partially reduced from C end. The purity of MBP-Antigen fusion protein was over 90%. The hyper-purified MBP-Antigen fusion protein was injected into BALB/C mice and antibodies were detected by ELISA. These antibodies could be applied in the diagnosis of AMI and myocardial damage.

Stepped Utilization of Xylose and Glucose in Fermentation of Fumaric Acid by Rhizopus arrhizus

LIU Ning XU Qing HE Hao WU Hua HUANG He JI Song-yang

. 2008, 8(4): 794-797.

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The fumaric acid production by Rhizopus arrhizus using xylose as the carbon source of seed culture medium and glucose as carbon source of fermentation medium was studied. In the seed culture, the biomass of Rhizopus arrhizus obtained using xylose was more than that using glucose. The conditions of the seed culture were optimized. The results showed that the optimal xylose concentration was 30 g/L, the suitable spore concentration range (4~6)×105 mL-1 and the seed age range 32~40 h. The final concentration of fumaric acid was 53.51 g/L in the fermentation medium containing 100 g/L glucose. The result implies that the problem of low conversion rate of xylose could be avoided, and the availability of xylose improved, which would facilitate further study on the stepped utilization of lignocellulose hydrolysate in fermentation of fumaric acid.

Preparation of S-2-Phenylpropionic Acid in Micro-aqueous Phase

ZHANG Bo ZENG Hong-yan WANG Ya-ju XIA Kun ZENG Liang HUANG Yan

. 2008, 8(4): 798-801.

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A new bio-enzymatic catalysis procedure of producing enantiomeric S-2-phenylpropionic acid was investigated. The effect of different alcohols on the esterification of 2-phenylpropionic acid was performed and the optimal alcohol was isopropanol. S-2-phenylpropionic acid was obtained by hydrolysis of 2-phenylpropionic ester catalyzed by penicillin G acylase (PGA) in the micro-aqueous phase. In the 95% (j) tetrahydrofuran solvent system, the optimal conditions were obtained as follows: enzyme PGA at 1.5 mg/mL, 2-phenylpropionic ester 0.3 g/mL, 30℃, and pH 7. The maximum yield and ee value of S-2-phenylpropionic acid were 94.5% and above 97.0%, respectively.

Fabrication and Characterization of Glass-infiltrated Zirconia All-ceramic Dental Composite

PENG Tong-an ZHU Qing-shan

. 2008, 8(4): 802-807.

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Zirconia-glass dental composites were fabricated by the melting infiltration process. The preforms were fabricated by both the slip casting and uniaxially pressing methods, and the perform pre-sintering and infiltration were consequently investigated. It shows that through optimizing the slip casting process, the solid content of the slurry can reach about 75%(w) and the slip-cast green body exhibits nearly no shrinkage after pre-sintering at 1200℃.The infiltration speed has also been much improved, where an infiltration distance of 3 mm can be reached whthin 15 min. The bending strength of the infiltrated composite was 285 MPa. On the other hand, with the dry pressing method, a pre-sintering temperature of ~1450℃ would be essential to get suitable green density and the infiltration speed is much slower (e.g. 2 h for 2 mm infiltration distance), as compared with the slip-cast performs. The fracture strength of the composite from the dry pressing was measure to be 400 MPa. The two perform forming processes of the dry pressing and slip casting would be well adaptable to different demands of making all-ceramic dental restorations.

Synthesis and Characterization of Cathode Material LiNi1/2Co1/6Mn1/3O2 for Lithium-ion Secondary Batteries

GUO Hai-peng JIA Meng-qiu LIAO Yu-zhao ZHAI Zhong-nan

. 2008, 8(4): 808-813.

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n1/3(OH)2 with 5% excess LiOH×H2O followed by heat treatment. The precursor Ni1/2Co1/6Mn1/3(OH)2 was prepared via multiple co-precipitation of solutions with different compositions of Ni2+, Co2+, Mn2+. The cathode material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The XRD pattern and the SEM photos of the material indicated that the layered crystal structure of the material with a-NaFeO2 type (space group R m) was perfect and its morphology was well distributed. The galvanostatic charge-discharge (0.1 C, 2.5~4.2 V, vs. Li+/Li) tests showed that not only the first discharge specific capacity of the gradient material was higher than that the homogeneous material, but its cyclic stability was improved greatly. The gradient material sintered at 800℃ delivered high discharge specific capacity of 171.2 mA×h/g after multiple cycling.

Conductivities of AlCl3/Ionic Liquid Systems and Their Application in Electrodeposition of Aluminium

YUE Gui-kuan LU Xing-mei ZHU Yan-li WANG Hui ZHANG Xiang-ping ZHANG Suo-jiang

. 2008, 8(4): 814-819.

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Solubilities and conductivities of anhydrous AlCl3 in six kinds of ionic liquids (ILs) were measured. Among the six kinds of ILs [bmim]Cl, [bmim]Br, [bmim]BF4, [bmim]PF6, [emim][EtSO4] and [bmim][HSO4], anhydrous AlCl3 could be dissolved in the first five kinds but was hardly dissolved in [bmim][HSO4]. The results showed that the nominal solubilities of AlCl3 in ILs increased in the order of [bmim][HSO4] < [bmim]PF6 < [emim][EtSO4] < [bmim]BF4 < [bmim]Cl < [bmim]Br. Conductivities of the AlCl3/ILs systems depended apparently on the nominal molar ratio of AlCl3 to ILs. The conductivities of AlCl3/[bmim]Cl, AlCl3/[bmim]Br and AlCl3/[bmim]PF6 systems had a similar tendency as a function of the nominal molar ratio, that is, as the molar ratio was increased, conductivities increased first and then decreased, with the maximum conductivity obtained at approximately 0.9:1, 1.0:1 and 0.5:1, respectively. Conductivities of the AlCl3/[bmim]BF4 exhibited a dentate change and decreased with the molar ratio of AlCl3 to [bmim]BF4 increasing in general. With the increasing of the anhydrous AlCl3 amount in [emim][EtSO4], conductivity of AlCl3/[emim][EtSO4] monotonically decreased. AlCl3/[bmim]Cl system was chosen as the electrolyte for the electrodeposition of Al. Preliminary experimental results showed that dense, adherent and homogeneous Al coatings could be electrodeposited on stainless steel by means of constant potential technique and the surface coverage was quite satisfactory.

Synthesis and Properties of Poly(Schiff-base) and Its Ferro-complex Containing Bithiazole Rings and Ferrocene

ZENG Dong-hai XIONG Guo-xuan

. 2008, 8(4): 820-824.

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A new poly(Schiff-base) containing ferrocene and bithiazole groups was synthesized, and characterized with FT-IR and 1H-NMR techniques. The effects of temperature, time and catalyst of reaction on its yield were investigated. The maximum yield of ferrocene Schiff-base was obtained as 87.2% under the conditions of 80℃ temperature and 6 h reaction time, and the maximum yield of poly(Schiff-base) was 72.4% with the catalyst of AlCl3. The thermogravimetric measurements suggested that the polymer had good thermal stability. At room temperature, the electrical conductivity and magnetic behaviors of the polymer and its complex were measured. The electrical conductivity of complex was declined when coordinated with Fe2+ metal salt, but through iodine doping, the electrical conductivity of poly(Schiff-base) was improved and the maximum room-temperature conductivity could reach 2.14×10-3 S/cm for poly(Schiff-base)-I2, meanwhile, the complex exhibited a typical "S" shape hysteresis cycle, the observed coercive field was 130 Oe, and the relative saturation magnetization and remnant magnetization 0.612 and 0.0257 emu/g for the complex, respectively. The result shows that the complex is a soft organic ferromagnetic material.

Preparation and Properties of the Nickel Ferrite Coated on Porous Silicon Carbide Ceramic

ZHAO Hai-tao WU Xiao-juan ZHANG Gang MA Rui-ting LI Xi-kun

. 2008, 8(4): 825-828.

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The nickel ferrite coated on porous SiC ceramic was prepared using polyacrylamide gel method with iron nitrate [Fe(NO3)3×9H2O], nickel nitrate [Ni(NO3)2×6H2O], acrylamide and N,N￠-methylenediacrylamide as raw materials. The morphology, structural characteristics and electromagnetic properties of the composite were analyzed. The results indicated that a pure spinel structure of NiFe2O4 formed on the porous ceramic at 600℃. The NiFe2O4 was better crystallized with the increase of annealing temperature. The nickel ferrite coating on porous SiC ceramic was uniform, continuous and consistent. The porous SiC ceramic belonged to a kind of dielectric loss material. And the porous SiC ceramic matrix with 1.3 mm pore diameter exhibited higher electromagnetic property compared with that with 1.0 mm pore diameter. The porous SiC ceramic coated with NiFe2O4 showed a better magnetic loss property. Its maximum value of the imaginary part of permeability was 0.4.

Preparation and Characterization of Agglomeration-free Sodium Chloride Particles Modified with SiO2 Nano-particles

DAI Meng-yan HU Bi-ru ZHANG Xue-ao WU Wen-jian

. 2008, 8(4): 829-832.

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By means of adding SiO2 nano-particles and surfactant F127 in the crystallization process of NaCl to modify the surface of crystals, the micrometer NaCl powder was prepared. The SEM analysis shows that SiO2 particles are adsorbed to the surface of NaCl crystals. The size distribution scope is 0.1~15 mm. It is found that the more the SiO2 nano-particles are added, the better the dispersion and fluidity become. The bulk density of NaCl particles is 0.6~0.8 g/cm3. The volumetric flow rate of NaCl particles is 4~6 mL/s. The results imply that such modification could effectively avoid water absorption and hard agglomeration of particles and improve their dispersion and fluidity.

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