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    20 August 2011, Volume 11 Issue 4
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    材料工程专栏
    Preparation of La2O2S:Yb,Er and Its Up-conversion Luminescence Property
    HAN Peng-de ZHANG Le YANG Hao WANG Li-xin ZHANG Qi-tu
    . 2011, 11(4):  0-0. 
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    La2O3:Yb,Er powder was prepared using coprecipitation and La2O2S:Yb,Er obtained by flux fusion method. Its crystalline structure and morphology were characterized by XRD and SEM, respectively, and its up-conversion emission property was tested by fluorescence spectrometer. The results showed when the co-precipitation temperature was 40℃, oxalic acid 5% excess, oxalic acid concentration 2.34%, pH value 5.53~6.45 and calcining temperature of La2O3 800℃, the idealized La2O3:Yb,Er could be prepared. Moreover, the optimal calcining temperature of La2O2S was 1250℃ for 3 h. The morphology of the particles was irregular. Their average size was about 1 mm. Green and red emission bands were observed when the powder was excited by 980 nm laser.
    流动与传递
    Measurement of Trailing Vortices around a Hydrofoil Impeller with PIV and Large Eddy Simulation
    CAI Qing-bai DAI Gan-ce
    . 2011, 11(4):  541-548. 
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    The trailing vortices around a hydrofoil impeller were investigated in a 0.383 m i.d. stirred tank with a 0.188 m i.d. hydrofoil impeller using PIV and LES. The comparison between angle-averaged axial velocities by LES and PIV data was in very good agreement, verifying the validity and effectiveness of LES simulation. The presence of trailing vortices formed around the hydrofoil impeller blades were indicated by the mean velocity vectors near the edge of blades, the contours of turbulence levels and kinetic energy of turbulence. It was found that single trailing vortex formed around each blade. The vortex axis was identified to fall on the cylinder swept by the blade tip. The effect of trailing vortices on the turbulence structure was also discussed. The maximum normalized kinetic turbulence energy k/Vtip2 was about 0.04~0.06, which was located at 0.5
    Comparison Study on Size Characterization of SiC Powder Particles Based on Continuous and Pulsed Ultrasonic Waves
    WU Jian SU Ming-xu CAI Xiao-shu WANG Wei-hui SUN Lei
    . 2011, 11(4):  549-553. 
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    In order to study the influence of continuous and pulsed wave excitations on particle size characterization, two experimental systems based on the waves have been established, and variable sound path method is adopted during the measurement to obtain the acoustic attenuation of SiC suspension with two immersion transducers at four different mass concentrations (14%, 17%, 20%, 25%) under the same experimental condition. It is shown that the results have the same tendency obtained with the two systems. The acoustic attenuation under continuous wave excitation is 10% larger than that of pulsed one in value due to the interference. It is found that the deviation of particle size distribution of SiC obtained with the inversion algorithm under the two different excitation modes is within 5%, which indicates that there is a little influence of different excitation modes on particle size characterization.
    反应与分离
    Adsorption of Cr(VI) in Waste Water by Functional Superparamagnetic PGMA Polymer Microspheres with Amino Groups
    LI Peng-fei YANG Liang-rong LI Wen-song HUANG Yin-bin WANG Juan KONG Peng XU Lin LIU Hui-zhou
    . 2011, 11(4):  554-560. 
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    Micron-sized monodisperse superparamagnetic polyglycidyl methacrylate (PGMA) particles with functional amino groups were prepared and characterized by SEM, FT-IR and XRD, respectively. The effect of pH value on the adsorption was studied. Their adsorption properties and mechanism for Cr(VI) from wastewater were investigated. In a model system, the adsorption process followed the Langmuir adsorption isotherm, and the maximum sorption capacity of was calculated to be 263.16 mg/g at 308 K and pH 4.5. The adsorption of Cr(VI) capacity reached equilibrium within 15 min and followed pseudo second order kinetics. The adsorption was a spontaneous and endothermic process with DH0=9.63 kJ/mol.
    Pilot Plant Study on Pressure Leaching of Nickel Laterite in Nitric Acid Medium
    MA Bao-zhong WANG Chen-yan YANG Bo YIN Fei ZHANG Yong-lu
    . 2011, 11(4):  561-566. 
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    A pressure leaching process of nickel laterite in nitric acid medium was studied in a pilot plant scale. The effects of reaction temperature, initial acidity, holding time, liquid-to-solid ratio and leaching pressure were examined through single-factor experiments. And the optimum leaching conditions were determined to be: reaction temperature 185℃, initial acidity 200 g/L, holding time 45 min, liquid-to-solid ratio 2 m3/t and leaching pressure 1.8 MPa. Under these conditions, the leaching rates of nickel, cobalt and iron were 84.50%, 83.92% and 1.08% respectively, which separated these three valuable metals, and had good stability. On this basis, leaching liquor purification and leaching agent recovery were also studied. The experimental results showed that nickel (cobalt) could be separated from aluminum, magnesium and calcium, meanwhile, the content of nickel in the nickel-cobalt containing residue could reach 25.40%, convenient for further processing, and the recovery rate of nitric acid could be 85%.
    Pressure Leaching of Manganese-containing Dust from Smelting with Sulfuric Acid
    XIE Hong-yan WANG Ji-kun LI Tian-jie MA Jin YANG Shi-cheng NA Ji-xin ZHANG Xue-wen
    . 2011, 11(4):  567-572. 
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    The pressure leaching of manganese smelter dust with air as pressurized gas in a sulfuric acid medium was studied. Optimum operating parameters were established as follows: ratio of liquid to solid 5 mL/g, initial sulfuric acid concentration 120 g/L, leaching temperature 120℃, partial air pressure 0.8 MPa, mass ratio of manganese smelter dust to pyrite 1:0.5, leaching time 2 h, and agitation speed of 500 r/min. Under these conditions, the leaching rates of Mn and Fe are 96.1% and 7%, and the residual rate of final acid is about 34.9%. Manganese can be effectively separated from impurities such as iron in the leaching process. The pressure leaching technique of manganese smelter dust is further proved to be effective and stable.
    Acid Leaching of Calcined Vanadium Titanomagnetite with Calcium Compounds for Extraction of Vanadium
    LI Lan-jie ZHANG Li ZHENG Shi-li LOU Tai-ping WANG Shao-na CHEN Dong-hui CHEN Dong-hui ZHANG Yan
    . 2011, 11(4):  573-578. 
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    After comparing the results of vanadium extraction by roasting the mixture of calcium-bearing regents with vanadium titanomagnetite concentrate and leaching by deionized water and roasting the mixture of sodium-bearing regents with iron concentrate and leaching by acid, the extraction method of vanadium by roasting the mixture of calcium-bearing reagents with iron concentrate and leaching by sulfuric acid is proposed. Among roasting additives of Na2CO3, CaO, Ca(OH)2 and CaCO3, CaCO3 has the best effect for vanadium extraction. The optimal roasting conditions obtained are the additive dosage 10%, roasting temperature 1200℃ and roasting time 1 h with CaCO3, and the primary vanadium-bearing phase generated is calcium metavanadate. It can be dissolved in sulfuric acid solution at pH<1.35 and 2.5~4, and in hydrochloric acid solution at pH<1 and 4~6.7. The sulfuric acid leaching results show that calcium metavanadate in iron concentrate roasted can be leached when pH at 0.5, mass ratio of liquid to solid at 5:1, 80℃ and 3 h. The leaching rate of vanadium is 72.1% from the roasted concentrate.
    Microwave-heated Alkali Activation, Water Dissolving and HCl Leaching of Used Firebrick from Glass Fiber Industry for Enrichment of Pt and Rh
    YAO Xian-zhao ZHANG Ze-biao PENG Jin-hui CHANG Jun LUO Xing LIU Yong-he
    . 2011, 11(4):  579-584. 
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    The process of microwave alkali-activation, water dissolving and HCl leaching to beneficiate Pt and Rh from discarded firebrick of glass fibre industry was studied. Comparison tests of microwave alkali-activation and conventional alkali-activation for discarded firebrick were carried out to investigate the effects of activation temperature, heating preservation time and additive dosage on alkali-activation reaction. The results show that the reaction is completed thoroughly when the test sample is alkali-activated by microwave at 800℃ for 30 min, with additive NaOH dosage of 140%. After the clinker is dissolved in water, the residue is leached at the optimum conditions of HCl 3 mol/L, leaching time 5 min and ratio of HCl to residue 15 mL/g. Slurry is filtrated well. The residue generation rate is 2.98%, and Pt and Rh are beneficiated about 33 times.
    Study on Application of Acidithiobacillus thiooxidans in Dephosphorization of Hematite in Enshi
    SUN Ling-zhi LI Shi-qi WANG Yu-jiao GAO Jin-tao WU Long JIN Xiao-hui
    . 2011, 11(4):  585-589. 
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    Dephosphorization of phosphorus-containing 0.90% high-phosphorus hematite ore in Enshi with the strain of Acidithiobacillus thiooxidans (At.t) was studied. The preliminary results showed that the maximum dephosphorization rate could reach up to 71%, which meant that Acidithiobacillus thiooxidans had a better dephosphorization effect. 10% of the strain concentration, 75 mm of hematite particles, 4.0 of initial culture pH value were obtained as the optimized leaching conditions by studying the growth characteristics of At.t and effects of different pH values, hematite particle sizes and At.t concentrations on the bioleaching process.
    Removal of Trace Al and Si Impurities in Sodium Chromate Solution
    GUO Wei YU Zhi-hui WANG Jing-gang QU Jing-kui QI Tao HAN Xiao-ying
    . 2011, 11(4):  590-594. 
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    By using simulated sodium chromate solution containing trace Al and Si impurities at 51.08 and 189.65 mg/L respectively, their removal was carried out with the reactions at atmospheric and high pressures. Under atmospheric pressure, when the elemental ratio of Al to Si in the solution with addition of NaAl(OH)4 was 6, and reaction time 40 min at 60℃, Si could be removed completely without addition of CaO. When CO2 pressure was 0.4 MPa in an autoclave, and reaction time 20 min at 60℃, Al could be removed completely. Chemically pure sodium chromate could reach the level of analytical purity after removal of Al and Si impurities. During dealumination in the autoclave, the carbonation reaction of sodium chromate also proceeded, pH value was gradually reduced with the reaction, and approached to stable state, showing that the carbonation reaction approached equilibrium.
    Removal of Arsenic in Steel
    LUO Lin-gen WANG Jian-jun KONG Hui ZHOU Li
    . 2011, 11(4):  595-598. 
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    Dearsenication by adding Ca-Fe alloy-based arsenic removal agent in molten steel was studied. The effects of oxygen content in the steel, Ca-Fe alloy adding amount and initial arsenic content in the steel on the removal process were investigated. The results showed that the removal rate of arsenic increased with the oxygen content in the steel treated. When the oxygen content was 1.0695′10-4(w), the removal rate was 37.5%. The removal rate increased gradually with increasing of Ca-Fe alloy adding amount. When the dosage of Ca-Fe alloy was 18%(w), the removal rate was 50%. The higher the original arsenic content in the steel, the higher the removal rate. When the original arsenic content was 8.00′10-4, its removal rate reached up to 77.5%. When Ca-Fe alloy was added with additive together, their interaction was more conducive to dearsenication, the highest removal rate of arsenic reached up to 81%.
    过程与工艺
    Experimental Study on Gas-based Reduction of Ultra-fine Oolitic High-phosphorus Hematite Powder
    LI Shi-qi ZHANG Yan-ting GAO Jin-tao LI Jin CHEN Pei-yu LIU Yun-zao WANG Yu-gang
    . 2011, 11(4):  599-605. 
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    The new device was developed for experimental study on gas-based reduction of ultra-fine oolitic high-phosphorus hematite. The phosphorus element existed in the form of apatite and embeded around the oolitic hematite and other gangue. However the iron did not exist with phosphorus element in a chemical combination state. The high-phosphorus hematite was finely ground to an average particle size of 2 μm by ultra-eddy grinding technique, so the effective dissociation of iron and phosphorus elements in the ore was achieved. The reduction results showed that the high reduction degree was achieved by new reduction device. The reduction degree was significantly affected by the particle size. Comparing the common particle size hematite powder (150 μm) and ultra-fine powder, the reduction degree of the latter reached 90%, which increased 30%. There was no sintering happening during reduction process, the preliminary separation of iron and phosphorus elements in the high hematite powder was achieved by simple magnetic separation device.
    Impact of Pulverized Coal Preheating on Coal Combustion Behavior in Pulverized Coal Injection of Blast Furnace
    ZHAO Jun-dong WANG Heng YANG Yong-chang DU Hui-jie SONG Guang-dong
    . 2011, 11(4):  606-612. 
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    By establishing the mathematical model and using own program based on Fluent software, the combustion of pulverized coal injected at different preheated temperatures was simulated, and the impact of different preheated temperatures on coal burning was examined. The model contained the heterogeneous reactions of coal with oxygen, carbon dioxide and steam, and the burning reaction of coke was also considered. The size and shape of raceway were determined, and the coal combustion space was divided into four zones which were treated with different assumptions respectively. The computational results show that when preheated pulverized coal is used in pulverized coal injection, the coal gasification is promoted in advance, the combustion region is moved forward, and the burnout rate of coal in the raceway is improved. When coal preheated temperature is increased 50℃, the coal burnout rate is raised 2% on average.
    Concentration of Fe3O4 in Roasted Slag from Copper Impoverishment Smelting
    YANG Tao HU Jian-hang WANG Hua LI Lei
    . 2011, 11(4):  613-619. 
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    A copper-containing slag from electric furnace impoverishment in Yunnan is recycled into the raw material by adding CaO for roasting in oxygen atmosphere. The influences of holding time, holding temperature, slag grain size, and gas phase atmosphere on magnetic roasting are investigated. SEM and XRD are used to analyze the microstructure and phase change of roasted slag. The influences of copper slag roasted by adding CaO and grain size are observed by TGA. The results show that the addition of CaO is effective in promoting the decomposition of Fe2SiO4. And the finer the grinding is, the better the reaction is. With increasing of roasting temperature and holding time, a-Fe2O3 is increased, Fe3O4 is first increased, and then decreased at 850℃. Excessively high temperature and long time are not conducive to the accumulation of Fe3O4, and a low oxygen potential is not conducive to the gas-solid reaction of Fe3O4 concentration. The optimal conditions of Fe3O4 concentration are air atmosphere, 850℃ and 2 h roasting.
    Study of Coagulation Mechanism of Particles in Liquid under Ultrasonic Treatment
    JIN Yan BI Xue-gong ZHANG Jing
    . 2011, 11(4):  620-626. 
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    Through simulation experiment, the mechanism of coagulation of particles in liquid under ultrasonic treatment was studied in order to guide the removing process of inclusions in liquid steel. The experimental results showed that in the ultrasonic power range of 15~30 W, the effect of acoustic stream was strong, and the particles in the liquid were forced to gather in the zone with low acoustic pressure. When the power level of ultrasonic treatment was less than a certain critical level (60 W in this work), the effect of ultrasonic vibration was stronger than that of cavitation, the particles in liquid were coalgulated to clusters, and the cavitation bubbles would help them coagulate. An empirical relationship between the diameter of particle clusters and input of ultrasonic power at this level was obtained as dcluster=0.539e0.523P (060 W).
    Effects of Calcium Salts and Amino Acids in Simulated Feed of Isoelectric Supernatant on Membrane Fouling during Bipolar Membrane Electrodialysis
    REN Hong-yan ZHANG Li-ye; WU Xia YANG Peng-bo CONG Wei
    . 2011, 11(4):  627-632. 
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    The individual role of Ca2+ salts and amino acids on membrane fouling from a bipolar membrane electrodialysis (BMED) of simulated monosodium glutamate isoelectric supernatant was studied with a constant voltage batch operation mode. Experimental results showed that some amino acids including Glu, Ala, Gly, Thr and Lys were detected in a content order of Glu>Ala>Gly>Thr>Lys in the base cell, which was proportional to their respective content in salt solution. The calcium existing in feed liquor was responsible mainly for fouling of the cationic exchange membrane (CEM) in contact with base cell, which resulted in some solid deposits on the CEM surface. During a consecutive batch BMED of simulated feed liquor with different amino acid contents, the end electrical conductivity gradually rose up with the batch going on, which increased from 1.32 mS/cm of the first batch to 10.56 mS/cm of the fourth batch for the feed liquor with the highest amino acid content. As an estimate of membrane fouling, the initial current was also characterized. It dropped down with the batch run and higher amino acid content, which was reduced from 3.91 A of the first batch to 3.27 A of the fourth batch for the feed liquor with the highest amino acid content. These results indicated that the amino acid tended to deteriorate some performance parameters of BMED. It was observed with SEM that the CEM of base cell suffered from some pollution to different degrees (JCM C>JCM B>JCM A) after the BMED of simulated feed liquor with different amino acid contents. With the further elemental analysis of the pollutant, the calcium and oxygen on polluted CEM surface were found to increase significantly, indicating that the pollutant could be deposits of Ca(OH)2/CaCO3 and amino acidic organic matter.
    Preheating System of Green Pellets with Rotary Kiln Direct Reduction Process
    LU Zhao-hui JIN Xiao-hui GAO Jin-tao CHEN Yu CHEN Dai-ming LI Shi-qi
    . 2011, 11(4):  633-638. 
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    The direct reduction of iron was carried out by pellet preheating and one-step coal-based direct reduction process with the high grade magnetite concentrate from Mengku, Xinjiang, as raw material. The quality of preheated pellets at different preheating system conditions was examined in order to determine the effect of preheating process when magnetite concentrate pellets were reduced. Both the compressive strength and degradation index of preheated pellet are the important indicators to measure the preheating process. The green pellets could be preheated in a chain grate to improve the strength of the preheated pellets and reduce the degradation index of green pellet. Based on the preliminary analysis of results, the best preheating system was determined, that is, the preheating temperature was between 800 to 850℃, preheating time 15~18 min, preheating wind velocity from 1.5 to 1.8 m/s and the material layer thickness 100 mm, the preheated pellets produced would have the compressive strength as high as 600 N, which means that its compressive strength is obviously improved compared with the pellets produced at other preheated system. The experimental results of scale-up process show that the quality of directly reduced iron under these conditions could completely meet the following production requirement.
    Process Characteristics of Cu-based Catalyst in Direct Synthesis of Methylchlorosilanes
    WANG Chao WANG Guang-run WANG Jin-fu
    . 2011, 11(4):  639-643. 
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    The copper-based catalyst promoted by a small quantity of zinc, tin and phosphorus was applied in the reaction between silicon powder and methyl chloride to synthesize methylchlorosilanes in a stirred bed. The effects of temperature, pressure and content of catalyst on the reaction rate and product selectivity were investigated. Under the conditions of 320℃ and 0.1 MPa, the reaction rate of 210 g/(kg×h) and the selectivity of 87.7% for dimethyldichlorosilane could be achieved in the steady period. Raising the temperature increased the reaction rate remarkably, while the selectivity began to decline above 330℃. The reaction rate obeyed first-order kinetic model to methyl chloride and the selectivity was hardly affected by the pressure below 0.3 MPa. Increasing the content of catalyst benefitted the reaction rate within limits, yet the steady period was shortened and the utilization efficiency of silicon reduced.
    系统与集成
    Simulation and Optimization of Ammonia Recovery with Ionic Liquid from Purge Gas in Ammonia Synthesis Plant
    CHEN Yan-jie YAO Yue-hua ZHANG Xiang-ping REN Bao-zeng WANG Lei DONG Hai-feng TIAN Xiao
    . 2011, 11(4):  644-651. 
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    A new ammonia recovery process of absorption and multi-stage flash distillation with ionic liquid [C4mim]BF4 as absorbent was designed, simulated and optimized. NRTL activity coefficient model was adopted, vapor-liquid equilibrium (VLE) data of ammonia and methane in the ionic liquid [C4mim]BF4 were regressed. The results showed that the NRTL model could correlate and predict the binary VLE systems containing ionic liquid well. Sensitivity analysis with Aspen Plus software was used to optimize the process, the effects of flow rate and temperature of absorbent on the molar concentration of ammonia in the purified gas were analyzed. The results showed that increasing the flow rate and reducing the temperature were conducive to the absorption of ammonia by [C4mim]BF4, the optimized operating conditions were mass flow rate 2000 kg/h and 30℃. The molar concentrations of ammonia in purified gas and the regenerated gas were 32.4′10-6 and 95.2%, meeting the design requirements, and energy consumption for per ton ammonia in this process was 940 kg standard coal, saving 200 kg standard coal, compared with the traditional process.
    Molecular Simulation on Microstructure of Ionic Liquids in Capture of CO2
    YUE Zhen-guo LIU Xiao-min ZHAO Yu-ling ZHANG Xiao-chun LU Xing-mei ZHANG Suo-jiang
    . 2011, 11(4):  652-659. 
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    Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids (ILs), [Emim]PF6, [Emim][Tf2N], [PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of CO2. Radial distribution function (RDF) and spatial distribution function (SDF) are used to analyze the microscopic properties of these systems. The calculated results show that the space distribution of CO2 around ILs determines the capability of ionic liquids for capturing CO2. Based on the analysis of SDF, CO2 and PF6- are overlapped partially around [Emim]+ in [Emim]PF6-CO2 mixture. When the anion is [Tf2N]-, cations are mainly distributed on one side of [Tf2N]- near N atom, and CO2 is concentrated on two sides near the fluoroalkylgroup (?CF3), and there is little overlapped district between cation and CO2. In [PC6,6,6,14]PF6-CO2 mixture, layered structure is found and CO2 is much nearer to PF6- than [PC6,6,6,14]+. Based on the analysis of RDF, in the phosphonium-based ILs, the highest distribution densities of anions and CO2 around cations are about 6 and 3 times as their average ones respectively, while in the imidazolium-based ILs, they are about 3 and 2 respectively, this means that the distributions of CO2 and anions around the imidazolium-based ILs are more evenly distributed than those around the phosphonium-based ILs.
    生化工程专栏
    Preparation and Characterization of Alginate-Chitosan Microcapsules Loaded with Pig Spleen Transfer Factor
    TANG Wen ZHOU Feng JIANG Biao FU Qiang ZHANG Wei FU Hua-lin
    . 2011, 11(4):  660-665. 
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    The microcapsules carrying pig spleen transfer factor were prepared by emulsion external gelatification method in an emulsion system with chitosan and alginate. Their characterization in diameter, loading rate, encapsulation efficiency, accumulative release in vitro and some other properties were studied. The results show that the microcapsules prepared based on the optimized formulation were sphere-like with the average diameter 11.05 mm, the loading rate was 11.60 mg/g, the encapsulation efficiency was 60.8%, and the accumulative release curve in vitro at pH 7.4 was fitted to first order kinetics equation, ln(1-Q)=-0.0692t-0.6449 (R2=0.9876). The preparation procedure is simple, and the microcapsules possess excellent sustained release and swelling behavior.
    Modification and Characterization of Agarose Gel with N-Hydroxysuccinimide
    WU Pu-qiang JIN Xiong-hua; XIA Hai-feng; ZHENG Zhi-yong; RAO Zhi-ming;
    . 2011, 11(4):  666-670. 
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    The homemade crosslinked agrose gel was first activated by allyl glycidyl ether, then reacted with mercaptoacetic acid and coupled with N-hydroxysuccinimide (NHS). Thus a kind of activated intermediate agarose gel with a 10-atoms-long arm and high specificity to amino-group was obtained. The modification density of NHS can be situated in a wide range of 20~150 mmol/mL by controlling the olefinic bond on the gel. This can reduce miscellaneous group coupling to the gel, and benefit for the ligand density design. The activated gel does not show any difference compared with original gel in physicochemical performance. The activated gel is easy to couple with L-phenylalanine in 30 min, and the coupling efficiency is greater than 90%. Moreover, the coupled ligands have been stable and without leaking during storage for 30 d.
    材料工程专栏
    Synthesis of Glycylglycine Imprinted Polymer Microspheres via Emulsion Polymerization
    HU Xiao-ling GUAN Ping WANG Chao-li YIN Ya-nan
    . 2011, 11(4):  671-677. 
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    Glycylglycine imprinted polymer microspheres (Gly-Gly-MIPMs) were synthesized by emulsion polymerization using glycylglycine as template, acrylamide as monomer and ethylene glycol dimethacrylate as crosslinker. The preparation conditions on the water phase morphology and size distributions of the influence and the polymer microspheres adsorption properties were discussed. The optimum preparation conditions were: mass ratio of emulsifier Tween-80 to Span-80 3:1, amount of 5% of monomer, initiator dosage of 1.1% monomer, reaction temperature 45℃, and stirring speed 450 r/min. Gly-Gly-MIPMs were monodisperse, with an average diameter of about 100 nm, imprinted polymers on two-Gly peptides showed better specific adsorption, which contained two different kinds of binding sites, and their imprinting factor was up to 2.18.
    Synthesis of Porous TiO2 Hollow Spheres by Hydrothermal Method and Their Adsorption Property to Cr(VI)
    XIANG Wei-cheng HU Peng ZHANG Xing YAO Ming-shui XU Rui-fen YUAN Fang-li
    . 2011, 11(4):  678-683. 
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    Anatase TiO2 was synthesized by a facile hydrothermal method. The analytical results of morphology and structure show that the product exhibits porous hollow structure with average diameter of 172 nm. The adsorption results of the product to Cr(VI) reveal that its adsorption ability is strongly dependent on the pH value of the solution. When the pH is 2.7, the maximum adsorption rate of Cr(VI) is obtained as 86%. With further increasing of pH value, the adsorbed rate of Cr(VI) decreases gradually. The adsorption data to Cr(VI) is well accordance with the Langmuir adsorption model, and the maximum adsorption capacity of the product for Cr(VI) is determined to be 23 mg/g through theoretical calculation. In addition, the adsorbed Cr(VI) could be easily eluted using alkali solution, which favors the recycle of the adsorbent. Addition of Cr(III) into the Cr(VI) solution does not influence its adsorption capacity to Cr(VI) apparently.
    Preparation and Application of Magnetic Fe(OH)3 Porous Microspheres in Treatment of Wastewater Containing Phosphorus
    SHI Zhong-liang SONG Yong-qiang GUO Xing XIE Cai-yue YAO Shu-hua
    . 2011, 11(4):  684-688. 
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    A composite adsorbent of magnetic Fe(OH)3 porous microspheres with Fe3O4 core was prepared, and characterized. The characteristics of phosphate adsorption on magnetic Fe(OH)3 porous microspheres were investigated. The influential factors such as the dosage of adsorbent, initial concentration of H2PO4?, solution pH value, co-existing anions in solution on removal of H2PO4? were examined. The adsorption isotherm of phosphate on porous microspheres could be described by Langmuir equation, and the adsorption kinetic data described by Lagergren second-order rate equation. The adsorbent had perfect properties in H2PO4? adsorption capacity, the removal rate of H2PO4? could be over 98% in the conditions of adsorbent dosage 0.8 g/L, and pH=2.5~9, adsorption time 150 min.
    Preparation of Si-Cu Composite with Electroless Copper Plating and Its Application in Lithium-ion Battery
    WANG Qian JIA Meng-qiu
    . 2011, 11(4):  689-694. 
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    Electroless copper plating on silicon particles was carried out with colloid palladium solution as activation liquid and NaH2PO2×H2O as reducing agent. The optimal coating conditions were obtained through orthogonal experiments. Phase analysis was run by XRD, SEM and TEM, and performance of electrochemistry examined by charging and discharging test. The results show that silicon surface is coated with a layer of dense copper particles. The Si-Cu composite anode of lithium-ion batteries shows good electrochemical performance, the initial discharge specific capacity reaches 1185 mA×h/g, after 30 cycles, the capacity gradually is reduced to 457 mA×h/g and can maintain 350 mA×h/g in the next 30 cycles. Therefore, Si-Cu composite can inhibit the volume effect of Si and improve the cycle performance of the electrode.
    Research on Properties of Low Fluorine CaF2-CaO-Al2O3-MgO-SiO2 Refining Slag
    SHI Guan-yong ZHANG Ting-an NIU Li-ping DOU Zhi-he
    . 2011, 11(4):  695-700. 
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    Low fluorine CaF2-CaO-Al2O3-MgO-SiO2 slag system was used as refining slag for preparation of Cu-Cr alloy. Its viscosity, density, surface tension and melting temperature were studied. The results indicated that the melting temperature of the slag was between 1336~1402℃. The density and surface tension of CaF2-CaO-Al2O3-MgO-SiO2 slag decreased with increasing of temperature, adding of CaF2 and MgO could decrease its density and surface tension. Its viscosity decreased with increasing of MgO and CaF2 content, and achieved the minimum value when MgO content was 6%, and increased when MgO content up to 9% with 10% and 15% CaF2 content. The slag had lower surface tension and better fluidity, so the refining efficiency with it was very good.
    Preparation and Adsorption Property of (-)-Epigallocatechin Gallate Surface Molecularly Imprinted Polymer
    Fei-fei DUAN Yu-qing ZHANG Hai-hui QIN Yu ZHANG Can MA Hai-le YAN Yong-sheng
    . 2011, 11(4):  706-710. 
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    Surface molecularly imprinted polymer (SMIP) was synthesized on the surface of g-aminopropyl triethoxysilane-modified silica gel with (-)-epigallocatechin gallate (EGCG) as template molecule, and methacrylic acid as functional monomer. The effects of solvent, pH value and temperature on the adsorption capacity of EGCG on SMIP were investigated. The Langmiur and Freundlich models were used to describe the adsorption behavior of EGCG on SMIP, and the adsorption kinetics and thermodynamic models were predicted. The results showed that the optimum adsorption conditions of SMIP on EGCG were as follows: the adsorption solvent was deionized water of pH 6, and temperature 25℃. Langmuir model fitted to the experimental data better than Freundlich isotherm. The adsorption kinetics of EGCG on SMIP could be described by the pseudo-first-order adsorption model and the pseudo-second-order adsorption model, and the thermodynamics was an entropy reduction process.
    Facile Synthesis of Gold-nanoparticles-decorated Polymer Assemblies and Core-Shell Gold Nanoparticles Using Pluronic Block Copolymers
    SHOU Qing-hui GUO Chen GAO Hong-shuai ZHOU Hua-cong LIU Chun-zhao LIU Hui-zhou
    . 2011, 11(4):  711-715. 
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    Synthesis of gold nanoparticles (AuNPs) and Pluronic triblock copolymer composite in aqueous medium was studied. Gold-polymer nanocomposite with different structures was fabricated by tailoring the molar ratio of gold precursors to Pluronic P123 molecules or pH value of the P123 solution. When a lower volume ratio of [AuCl4-]/[P123] (0.05) was employed at pH 11.1, a nanostructure similar to plum pudding was obtained. AuNPs with an average diameter of 13.1 nm were embedded in Pluronic assemblies, and each one held about 21 single gold nanoparticles. When [AuCl4-]/[P123] was increased to 0.1, core-shell structure was obtained if the pH value was in the range of 10.6~11.6, while gold polyhedra were fabricated when pH value was 8.1. Typical core-shell AuNPs had an average diameter of 9.6 nm with a narrow size distribution, while gold polyhedras with a mean diameter of 12.8 nm was obtained. The specific morphologies of the resultant nanocomposite were presumably obtained due to the synergistic interaction among the reactants.
    Carbon Coating on the Fiber Surface with Single Pulse Copper Plating
    GAO Song FAN Ming-jie WANG Gui-ping
    . 2011, 11(4):  716-720. 
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    Pulse copper plating was used to coat a copper film on the carbon fiber surface. The effects of CuSO4, H2SO4, additives, electroplating time, current density, and duty cycle on the weight gain rate were investigated. And the solution composition and technical parameters for pulse copper plating were determined. The bonding force between the coating and the carbon fiber was tested by psychro-thermal cycles. The quality of copper coating was examined with SEM and XRD. The composition of electroplating solution was 130 g/L CuSO4×5H2O, 50 g/L H2SO4, 30 g/L KNO3 and 6 mL/L brightener. Under ambient temperature, the optimum technical parameters were 82 mA/mm2 of current density, 40% of duty cycle, 6 min of electroplating time, with the conditions a flat, detailed and well-crystalloid coating on the carbon fiber surface was achieved. Coating adhesion was increased from 270 kPa to 450 kPa.