The Chinese Journal of Process Engineering

Composting of Disposal Organic Wastes: Resource Recovery for Agricultural Sustainability

Mohammad H. Golabi Mohammad H. Golabi;

. 2006, 6(4): 0-0.

Asbtract ( )

PDF (544KB) ( )

Related Articles | Metrics

One of the major problems of agricultural soils in the tropical regions of the Pacific is the low organic matter content. Because of the hot and humid environment, the soil organic matter (SOM) is minimal due to rapid decomposition. Composted organic material is being applied on agricultural fields as an amendment to provide nutrients and enhance the organic matter content for improving the physical and chemical properties of the cultivated soils. In addition land application of composted material as a fertilizer source effectively disposes of wastes that otherwise are buried in landfills. In our soil program at the University of Guam, we are evaluating the use of organic material as an alternative to synthetic fertilizers. Its goal is to develop management strategies and use available resources for improving crop production while conserving resources and preserving environmental quality. Our case study project is designed to improve soil fertility status by using composted organic wastes and assessing how the nitrogen and other essential nutrients contribute to long-term soil fertility and crop productivity without application of synthetic fertilizers. In our pilot project, compost is produced from wood chips, grinded typhoon debris mixed with animal manure, fish feed, shredded paper and other organic wastes. Mature compost is then applied on the field at the rates of 0, 5, 10 and 20 t/ha as a soil amendment on the eroded cobbly soils of southern Guam. Corn is planted and monitored for growth performance and yield. The effect of land application of composted material on the SOM content and overall soil quality indices are being evaluated in this pilot study.

Flow Behavior of High-sulfur Petroleum Coke with Different Particle Size Distributions in a Novel Strong Mixing Reactor

RUAN Yu-jun;LU Chun-xi;SHI Ming-xian

. 2006, 6(4): 517-521.

Asbtract ( )

PDF (220KB) ( )

Related Articles | Metrics

The flow behaviors of high-sulfur petroleum coke with three different particle size distributions in a novel strong-mixing riser reactor were systematically investigated. The reactor was mainly composed of the pre-mixed zone and the lift zone, the structural dimensions of the two zones were respectively 240 mm ID, 3000 mm length and 70 mm ID, 9000 mm length. The experiment was carried out with the superficial gas velocity from 8 to 18 m/s and solids circulating rate from 60 to 200 kg/(m2×s). Through the experimental measurements on the axial and radial distributions of solids holdup and velocity in the strong-mixing riser reactor, it is found that, with increasing the proportion of fine powder in the coarse particles appropriately, the cross-section mean solids velocity will reduce, and the solids holdup will increase, moreover the back-mixing of particle is intensified and the residence time of particle will extend, which are beneficial to sufficient combustion of high-sulfur petroleum coke.

Criteria on the Similarity of Melt Flow among Strands in Multi-strand Continuous Casting Tundish

ZHENG Shu-guo;ZHU Miao-yong

. 2006, 6(4): 522-526.

Asbtract ( )

PDF (239KB) ( )

Related Articles | Metrics

The residence time distribution (RTD) curves become a very popular means of characterizing the melt flow in multi-strand tundishes to optimize the fluid flow and the flow control devices. For the melt flow in multi-strand tundishes, the inclusion removal as well as the similarity among the strands should be considered. Since there is no well-known approach to quantify the similarity among the strands in multi-strand tundish, a new approach for quantifying the similarity among the strands was proposed. And its reasonability was discussed by comparing it with other approaches conventionally used, by means of the measured results of a physical model for a six-strand tundish. As a result, the new approach proposed is better than the others in quantifying the similarity among the strands, as it takes each point of the RTD curves of each strand into consideration.

Evaluation of the Effect of Ultrasonic on the fouling Inhibition by Heat Transfer Coefficient Measurement

REN Xiao-guang;LI Tie-feng;SONG Yong-ji;MA Qing

. 2006, 6(4): 527-530.

Asbtract ( )

PDF (254KB) ( )

Related Articles | Metrics

Pool boiling in CaCO3 solution was performed to determine the heat transfer system through data acquisition system and dynamic experiments. Under the conditions of different CaCO3 concentrations and heat fluxes, the ultrasonic was introduced to test its effect on the fouling accumulation on the metal surface. The temperature measurements at the different points on the heating element were transformed to heat transfer coefficient, so that the fouling inhibition function can be evaluated. The results show that the ultrasonic not only enhanced the boiling heat transfer, but also prevented the formation of the fouling on the metal surface, very good fouling inhabiting performance being demonstrated.

Continuous Synthesis of Dimethyl Carbonate by Supercritical CO2 Extractive Reaction

CUI Hong-you;WANG Tao;DAI You-yuan

. 2006, 6(4): 531-538.

Asbtract ( )

PDF (220KB) ( )

Related Articles | Metrics

Dimethyl carbonate (DMC) is an important green chemical. The distribution coefficients of DMC, methanol, ethylene glycol (EG) and ethylene carbonate (EC) between the supercritical CO2 phase and the liquid phase in the one-pot synthesis of DMC were determined under various conditions, and the separation factors of DMC corresponding to methanol, EG and EC were calculated. The experimental results showed that DMC-methanol separation factor decreased with EC content in the mixture，increased with the contents of DMC and EG, enhanced with pressure and declined with temperature. These results indicated that the prerequisites of supercritical extractive reaction to promote the transesterification conversion were: (1) keeping high DMC concentration in the reaction mixture, namely, relatively high EO/methanol ratio in the feed solution and high EC conversion rate; (2) low reaction temperature and high reaction pressure. The feasibility of one-pot continuous synthesis of DMC by supercritical extractive reaction was explored using EO, methanol and CO2 as raw materials at 160℃ in the pressure range of 5~20 MPa. Both the experimental results and process analysis showed that DMC-methanol separation factor is a key factor which affects DMC yield in the supercritical extractive reaction. Supercritical extractive reaction could get more than 4% DMC yield in single-stage compared with that without supercritical extraction.

Oxidation Burning Reaction Kinetics of Acetic Acid in a Liquid Phase Catalytic Process

LI Da-ren;JIN Hai-bo;SHI Gao-feng

. 2006, 6(4): 539-543.

Asbtract ( )

PDF (201KB) ( )

Related Articles | Metrics

The kinetics of oxidation burning reaction of acetic acid in liquid-phase catalytic processes is studied in a semi-batch stirred titanium reactor by measuring the formation concentrations of CO2 and CO with cobalt acetate and manganese acetate as main catalyst, potassium bromide as promoter, and potassium acetate as assistant catalyst. The effects of air flow, temperature, total catalyst concentration, [Co]/[Mn] ratio, bromide concentration, water content on the catalytic burning loss rate of acetic acid are discussed. The experimental results show that the formation rate constants of CO2 and CO increase remarkably with increasing [Co]/[Mn] ratio and total catalyst concentration. The loss of acetic acid in oxidation processes is restrained by increasing [Br]/[Co] ratio and decreasing the reaction temperature. Meanwhile, the reaction activation energy values of CO2 and CO are obtained as 88.11 and 127.31 kJ/mol respectively.

Kinetics of Antimony Leaching from Oxidizing-Converting Slag of Pb-Sb Alloy by HCl-NaCl

ZHANG Rong-liang;TANG Shu-zhen;SHE Yuan-yuan;QIU Ke-qiang;HU Han-xiang

. 2006, 6(4): 544-547.

Asbtract ( )

PDF (167KB) ( )

Related Articles | Metrics

The kinetics of antimony leaching from oxidizing-converting slag of Pb-Sb alloy by HCl-NaCl was approached using the shrinking unreacted core model for the reaction of liquid-solid. The influences of temperature, hydrochloric acid concentration and particle size on the reaction rate of antimony were investigated in detail. The results show that the diffusion through the solid film is the rate limiting step in the process of antimony leaching from oxidizing-converting slag. The apparent reaction progression is 0.2775, and the apparent activation energy is calculated to be 7.656 kJ/mol within the selected temperature range from 55℃ to 95℃, which is characteristic of diffusion controlled leaching process. Based on the experimental data, the kinetic equation of reaction is given by 1-2/3a-(1-a)2/3=6.7583′10-12d-2cHCl0.2775exp[-7656/(RT)]t.

Experimental Investigation of Production Behavior of Gas Hydrate under Thermal Stimulation

Tang Liang-guang;XIAO Rui;LI Gang;FENG Zi-ping;LI Xiao-sen;FAN Shuan-shi

. 2006, 6(4): 548-553.

Asbtract ( )

PDF (270KB) ( )

Related Articles | Metrics

The temperature distribution and flowing characteristics of the dissociated gas and water from hydrate bearing porous sediments were investigated by utilizing a one dimension experimental model setup. With the developed apparatus, the gas hydrate was formed by mixing methane gas with NaCl solution at proper temperature and pressure condition. The experiments were run for the thermal stimulation method by injecting hot water at different temperatures and rates. The experimental results suggest that the gas production rate increases with time until it reaches a maximum and then it begins to decrease. However, the water production rate keeps nearly constant during the whole production process. The calculated energy ratio for all experimental runs is in the range of 0.38~2.59. The injection water temperature and rate as well as the hydrate content in the sediment all influence the energy ratio of thermal stimulation production.

Preparation of White Carbon Black with Lime-kiln Gas by Carbonization

HE Kai;CHEN Hong-gang

. 2006, 6(4): 554-559.

Asbtract ( )

PDF (210KB) ( )

Related Articles | Metrics

The preparation technology of white carbon black (WCB) from water glass and simulative lime-kiln gas is studied systematically and experimentally by carbonization method, in which exhaust gas from production of calcium carbonate is utilized. The experiments are carried out by examining the influences of reaction temperature, reaction time, material ratio, carbon dioxide content on the yield of WCB and product characteristics (average particle diameter of WCB and rate of DBP absorption). The optimum experimental conditions have been gained as follows: reaction temperature 85~95℃, reaction time 2.5 h, volumetric ratio of water glass to water 1:6, and carbon dioxide content of simulative lime-kiln gas 40%. The present results would offer important reference for industrialisation of preparation technology of white carbon black as inorganic filling agent with fine capability and high compensation.

The Influence of CaF2 and NdCl3 on Physicochemical Properties of Mg-containing Electrolyte

CHEN Jin-zhong;LIU Jiang-ning;LI Bing;WANG Jin;YU Jian-guo

. 2006, 6(4): 560-565.

Asbtract ( )

PDF (266KB) ( )

Related Articles | Metrics

The influence of CaF2 and NdCl3 on physicochemical properties of Mg-containing electrolyte for magnesium electrolysis was studied. The composition of the used molten salt was 18%MgCl2-25%CaCl2-37%NaCl-20%KCl. The crystallized temperature, density, conductivity and surface tension of the molten electrolyte with addition of CaF2 and NCl3 were measured. The results show that the influence of CaF2 on the surface tension of molten salts is obvious. The surface tension changes from 1.02 to 1.39 N/m when the content of CaF2 is increased from 0 to 5%. The crystallized temperature and density changes slightly when the content of CaF2 is low. The influence of NdCl3 on physico-chemical properties of the melt salt is not remarkable.

Electrochemical Oxidation of Isothiazolin-ketone Using a Ti/SnO2+Sb2O3/b-PbO2 Anode

HAN Wei-qing;ZHOU Gang;WANG Lian-jun;SUN Xiu-yun;LI Jian-sheng

. 2006, 6(4): 566-570.

Asbtract ( )

PDF (475KB) ( )

Related Articles | Metrics

Ti/SnO2+Sb2O3/b-PbO2 electrode was prepared by coating and electro-deposition method. The structure and property of electrode were also analyzed by SEM, XRD and steady state polarization curve. In this study, electrochemical oxidation using a Ti/SnO2+Sb2O3/b-PbO2 anode was applied to treat an isothiazolin-ketone solution. The kinetics of isothiazolin-ketone degradation and chemical oxygen demand (CODcr) destruction was investigated, while the operating parameters affecting the mechanism were also studied. The parameters investigated included current density, electrochemical oxidation time and pH. 98% isothiazolin-ketone and 43% CODcr were removed at a current density of 15 mA/cm2, initial isothiazolin-ketone of 200 mg/L and oxidation time of 180 min. The intermediates of electrochemical oxidation were analyzed by UV spectrum. The heterocycle of the isothiazolin-ketone was firstly disconnected and oxidated into some organic acids, then the organic acids were oxidated into CO2 and H2O.

Biodiesel Preparation from Transesterification of Cotton Seed Oil by Solid Acids Catalysis

CHEN He;WANG Jin-fu

. 2006, 6(4): 571-575.

Asbtract ( )

PDF (217KB) ( )

Related Articles | Metrics

Methyl esters (biodiesel) were produced by transesterification of cottonseed oil with methanol in the presence of solid acids as heterogeneous catalyst. The solid acids were prepared by mounting H2SO4 on TiO2×nH2O and Zr(OH)4, respectively, followed by calcining at 823 K. TiO2-SO42- and ZrO2-SO42- were employed as catalyst for transesterification with high activity. The yield of methyl esters reached over 90% under the conditions of 230℃, methanol/oil mole ratio of 12:1, reaction time 8 h and catalyst dosage (catalyst/oil) of 2%. The solid acid catalysts have more adaptability than the solid bases catalysts when the oil has high acidity. Spectral analysis of absorbing pyridine IR of the samples showed that there were Lewis and Bronsted acid centers on the catalysts.

Factors Affecting Output Power in Electro-generative Leaching System of Chalcopyrite

XIAO Li;LIU Jian-she;FANG Zheng;QIU Guan-zhou

. 2006, 6(4): 576-579.

Asbtract ( )

PDF (236KB) ( )

Related Articles | Metrics

The generative principle was applied to leaching process of CuFeS2-FeCl3(aq) and CuFeS2-MnO2 in this study. It was confirmed that a certain quantity of electrical energy along with the leached products could be simultaneously obtained during the process. The factors affecting the power output, such as grain size of concentrate and graphite paste in working electrode, NaCl concentration and pH value of anodic solution, temperature, different systems of cathode, and HCl concentration of cathodic apartment, were investigated by using an orthogonal design and factorial experiments. The results indicated that the materials of cathode were very important, then followed by concentrations of NaCl and HCl of the leaching system. The leaching conditions were optimized according to their effects on the maximal output power. It was shown that the generative impeding factor was mainly solid sulfur gathering on the surface of working electrode based on the discharging experiments under constant resistance in 6 h. Therefore, eliminating elemental sulfur is the key measure to maintain the output power.

Influence of Boehmite Particle Size on the Formation of a-Alumina Powder by Calcination

LI Shao-hua;YUAN Fang-li;HU Peng;KE Jia-jun

. 2006, 6(4): 580-584.

Asbtract ( )

PDF (648KB) ( )

Related Articles | Metrics

The influence of particle size of boehmite powder on the formation of a-Al2O3 powder during the subsequent calcination process was studied. Three kinds of dispersive boehmite precursor particles with nano, submicron and micron-scaled grain sizes were prepared by hydrothermal method. Crystalline phases and morphologies of the powders produced by calcination of boehmite at different temperatures were analyzed with XRD and the electron microscopy. The experimental results showed that calcination of 30~100 nm boehmite particles at 1200℃ for 1 h resulted in the formation of single-phase a-Al2O3, and the product powder consisted of vermicular particles. 0.4~0.6 mm boehmite particles were fully converted to a-Al2O3 by calcination at 1250℃ for 1 h, and the product powder consisted of porous plate-like particles in the same range of 0.4~0.6 mm in size. The product powder was still composed of a little proportion of transition alumina besides a-Al2O3 by calcination of 1 mm boehmite particles at 1350℃ for 2 h, and the particles were sintered severely. Therefore a-Al2O3 powder in the sub-micron size range with good dispersivity could be obtained by calcination of submicron-scaled boehmite powder prepared by hydrothermal method.

Optimization of Mixed Liquid Suspended Solids Concentration in a Membrane Bioreactor with Gravitational Draining

ZHENG Xiang;LIU Jun-xin

. 2006, 6(4): 592-597.

Asbtract ( )

PDF (196KB) ( )

Related Articles | Metrics

In comparison with the conventional activated sludge process, membrane bioreactor (MBR) offers the advantages of a smaller footprint due to higher biomass concentrations and a complete removal of solids from the effluent. As aeration system for fouling control and oxygen supply counts for more than 90% of total energy cost in MBR, it is important for the design of the aeration system. Generally operational cost and mixed liquid suspended solids (MLSS) concentration were inversely proportional to each other, which means that membrane flux and a value are minimized when MLSS concentration is maximized and vice versa. Therefore, MLSS concentration was considered to be a key parameter for the operation of MBR. In order to achieve the optimum MLSS concentration, the relationship between these parameters (including membrane flux, a value and pollutant removal rate) and MLSS (3.9~18.4 g/L) were investigated in the study. It clearly showed that viscosity of sludge increased with higher MLSS. The viscosity of sludge increased from 5.4 mPa×s at MLSS of 4.8 g/L to 680 mPa×s at MLSS of 18.4 g/L. The relationship between viscosity of sludge and MLSS can be indicated with the equation h=e0.1635c+0.055. The a value, which defines the relation of oxygen transfer in pure water to oxygen transfer in activated sludge, decreased from 0.89 at MLSS of 4.8 g/L to 0.10 at MLSS of 18.4 g/L. However, the MLSS concentration had no impact on pollutant removal rate of COD, NH4+-N and TN when MLSS exceeded 4.8 g/L. Therefore, optimum MLSS concentration was turned out to be 4 g/L to 6 g/L in the case of typical municipal wastewater.

Controllable Preparation and Characterization of Imiquimod-loaded Nanostructured Lipid Carriers

ZHOU Hua-feng;MA Quan-hong;DING-Yi;XIA Qiang;HAO Xiao-zhen;GU Ning

. 2006, 6(4): 598-602.

Asbtract ( )

PDF (277KB) ( )

Related Articles | Metrics

Imiquimod-loaded nanostuctured lipid carriers (IMQD-NLC) were prepared by high pressure homogenization method. The influences of surfactant, high pressure homogenization parameter and capacity loading on the preparation of IMQD-NLC were explored. Additionally, its morphology, crystalline phase, Zeta potential and release in vitro were characterized. The results show that there was a trend toward increasing the particle size of IMQD-NLC and decreasing the absolute value of Zeta potential with increasing the content of S-40 in the combined surfactant of S-40 and Span-20. Both the particle size and PI value were lower with the many cycle times, while ascending with increasing the content loading. IMQD-NLC, characterized by XRD, was amorphous. It was confirmed that burst release occurred followed by a sustaining release at pH 1 and a sustaining release at pH 5.5 in vitro for IMQD-NLC. Consequently the preparation of IMQD-NLC can be controlled by altering the conditions of preparation to realize sustained release effect.

Preparation of Uniform-sized PLA/PLGA Microcapsules Containing Lysozyme by Combining Porous Glass Membrane Emulsification and Multiple Emulsion-solvent Evaporation

HUANG Shan-shan;LIU Rong;MA Guang-hui;TAN Tian-wei

. 2006, 6(4): 603-607.

Asbtract ( )

PDF (307KB) ( )

Related Articles | Metrics

Relatively uniform-sized biodegradable poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) microcapsules containing lysozyme were successfully prepared by combining porous glass membrane emulsification technique with multiple emulsion-solvent evaporation method. Compared with the stirring method, it was found that the sizes of microcapsules are more uniform, the coefficient of variation (CV) value which indicates the size distribution was 14.04%. It was found that adding additives to inner aqueous phase could efficiently improve the drug encapsulation efficiency, adjust the drug release profile and maintain the bioactivity of drug. When PVA, PEG400 and HP-b-CD were separately added into the inner aqueous phase, the encapsulation efficiency increased from 68.1% to 86.6%, 89.0% and 94.1% respectively. The cumulative release amount was decreased when PEG400, PEG6000, HP-b-CD were added. While it was enhanced when PVP or PVA was added. It demonstrated that the main reason for protein deactivation was lysozyme adsorption onto the W1/O interface. The loss of lysozyme activity was successfully prevented by adding PEG400, PEG6000, HP-b-CD or PVP into the inner aqueous phase.

Preparation and Characterization of Chitosan Microcapsules Crosslinked by Vanillin

LI Qiao-xia;SONG Bao-zhen;YANG Zhen-qiu;FAN Hong-lie

. 2006, 6(4): 608-613.

Asbtract ( )

PDF (410KB) ( )

Related Articles | Metrics

Chitosan microcapsules crosslinked with vanillin were prepared by emulsification-crosslinking method. After the chitosan aqueous phase was emulsified into the sunflower oil containing Span-80 as emulsifier by stirring to obtain microdroplets, vanillin solution was added to crosslink the microdroplets. Acetone, the optimal solvent of vanillin, was chosen by comparing the formation and shape of chitosan microcapsules. SEM photographs showed that chitosan microcapsules were spherical and had compact surface and interstitial inner structure. FT-IR and XRD spectra showed that the formation mechanism of chitosan microcapsules was due to the crosslinking reaction between amino groups from chitosan and aldehyde groups in vanillin and the dehydration of chitosan microdroplets by acetone. The influence of the degree of deacetylation (DD) and viscosity-averaged molecular weight (Mv) of chitosan and the amount of vanillin on the properties of the chitosan microcapsules was investigated. It was found that the yield and naproxen content of microcapsules and naproxen loading efficiency increased, while the rate of drug release in vitro decreased, with the increase of the DD and Mv of chitosan and the amount of vanillin. Chitosan microcapsules prepared with chitosan (DD=96.3%, Mv=6.05′105) and vanillin of which the ratio of aldehyde group to amino group is 3.75:1 can be released completely in the pH 5.6 buffer containing 0.5 g/L lysozyme simulating the environment of colon.

The Dissolution and Enzymatic Hydrolysis of Casein by Dynamic Light Scattering

LIU Rui;QI Wei;SU Rong-xin;JIN Feng-min;HE Zhi-min

. 2006, 6(4): 614-618.

Asbtract ( )

PDF (253KB) ( )

Related Articles | Metrics

The effects of temperature, ionic strength and enzymatic hydrolysis on the average hydrodynamic radius (Rh) of casein micelles in phosphate buffer were studied by using dynamic light scattering. The results showed that the average Rh value of casein micelles was reduced irreversibly by heating. It was decreased with the increase of ionic strength in low ionic strength solution (<0.05 mol/L), but on the contrary in high ionic strength solution (>0.1 mol/L). The Rh value of casein increased rapidly during the process of enzymatic hydrolysis, and the structural model of casein in enzymatic hydrolysis was also proposed, i.e., the casein micelle stretched into incompactly and regularly flocky peptides from compact sphere.

Preparation and Characterization of the rhIFN-a-2a Modified by Polyethylene Glycol with Different Molecular Weights

ZHANG Lin-lin;ZHENG Chun-yang;LEI Jian-du;MA Guang-hui;SU Zhi-guo

. 2006, 6(4): 619-622.

Asbtract ( )

PDF (334KB) ( )

Related Articles | Metrics

Monomethoxy polyethylene glycol with different molecular weights (mPEG5000, 10000 and 20000) were prepared using activated N-hydroxysuccinimede (NHS). NHS-mPEG was investigated by hydrolysis kinetics. Through the experiments based on orthogonal design, the optimized reaction conditions could be proposed to obtain a single PEG chain attached onto the rhIFN-a-2a. Ion exchange chromatography was used to separate and purify PEGylated rhIFN-α-2a products from unPEGylated rhIFN-α-2a. PEGylated rhIFN-a-2a with different molecular weights was contrasted by in vitro bioactivity and protein recovery rate. It was revealed that with the increase of molecular weight of NHS-mPEG, the modification reaction conditions were higher and the in vitro bioactivity was lower, but the protein recovery rate was increased.

Kinetic Analysis of Stimulatory Effects of Amino Acids on Glycerol Formation

XIE Tao;FANG Hui-ying;ZHUGE Jian

. 2006, 6(4): 623-626.

Asbtract ( )

PDF (197KB) ( )

Related Articles | Metrics

The effects of glycin, glutamic acid, asparagin, pyruvic acid and a-oxoglutarate as additives on cell growth, maintenance, byproducts formation and glycerol production by C. glycerinogenes were investigated. The results showed that the addition of the above substances had little influence on cell growth during the whole fermentation process. However, it could hasten the glucose consumption rate, shorten the fermentation time, and enhance the glycerol yield on glucose. The glycerol productivities reached 1.66, 1.59, 1.61, 1.54 and 1.68 g/(L×h), respectively. As compared with the control, the glycerol productivities increased 25.18%, 19.21%, 20.77%, 15.92% and 26.32%, respectively. Further analysis indicated that the byproduct was mainly produced during the rapid growth phase, where the glucose consumption in cell growth, maintenance and glycerol production had little change. During the steady growth phase, the glucose consumption for cell growth, maintenance and byproducts formation decreased, thus resulting in the incremental carbon metabolic flux toward glycerol biosynthesis pathway.

Wavelet Multi-fractal Singularity Spectrum: Application to Pressure Fluctuation in an Impinging Stream Mixer

ZHANG Jian-wei;JIAO Li

. 2006, 6(4): 627-632.

Asbtract ( )

PDF (279KB) ( )

Related Articles | Metrics

In order to understand the intrinsic features of heterogeneity, non-linearity and chaotic behavior of fluid system in an impinging stream mixer, the wavelet transform modulus maxima method and multi-fractal measurement analysis were presented to describe the heterogeneity features of the pressure fluctuation in the impinging area. Based on the method, the multi-fractal singularity spectra of pressure fluctuation signals were measured in the impinging stream mixer. The multi-fractal characteristic of pressure fluctuation signal is shown in the impinging stream mixer and the exponent H values are from 0.5 to 3.5, whereas H>1.0 is shown with r≤20 mm. Thus, r≤20 mm is considered as the radial limitation in the impinging area.

Application of the Solvothermal Process in the Synthesis of High-performance Ag/g-Al2O3 Catalysts

;;;

. 2006, 6(4): 633-638.

Asbtract ( )

PDF (411KB) ( )

Related Articles | Metrics

Ag/g-Al2O3 is a kind of promising catalyst with the relatively lower cost compared with those using noble metals, good resistance against catalytic poisoning and excellent behaviour for NOx removal. In the present study, Ag/g-Al2O3 catalysts were synthesized by the solvothermal process and characterized by XRD, TG-DTA, TEM, UV-Vis and FT-IR. It was found that high-performance Ag/g-Al2O3 catalysts could be synthesized by properly selecting starting materials, controlling the composition of solvent and other reaction conditions. The microstructure evolution of the catalysts was also discussed.

Preparation of Porous Photocatalytic Materials by Electroless Composite Plating Method and Their Photodegradation Performance

SUN Tong;ZHAI Yu-chun;MA Pei-hua

. 2006, 6(4): 639-644.

Asbtract ( )

PDF (320KB) ( )

Related Articles | Metrics

Porous titanium dioxide-based photocatalytic materials with porous nickel as carrier were prepared by electroless composite plating method. The photocatalytic performance of products was estimated by degrading Rhodamine B solution. The reaction of photocatalytic degradation of Rhodamine B follows the zero order kinetic law. The optimum conditions for preparing porous photocatalytic materials by electroless composite plating method are 20 g/L nickel sulphate, 20 g/L sodium hypophosphite and 0.28 g/L P-25 nanometer titanium dioxide in the electroless composite plating solution, 90℃ and pH=4.6. The order of factors affecting products performance is concentration of nickel sulphate > concentration of sodium hypophosphite > the temperature of electroless composite plating solution > pH > the dosage of P-25 nanometer titanium dioxide. Doping of bismuth oxide can decrease the photocatalytic performance of products. But the photocatalytic performance of products increases as compound dosage of bismuth oxide increases. Doping of zinc oxide can improve the photocatalytic performance of products and the more the zinc oxide, the better the photocatalytic performance of products. Depositing silver on the bismuth oxide composite materials makes the photocatalytic performance of materials decrease. But depositing silver on the zinc oxide composite materials increases the photocatalytic performance of materials

Heterogeneous Photooxidation of Phenol by Catalytic Membranes

;;;

. 2006, 6(4): 645-650.

Asbtract ( )

PDF (284KB) ( )

Related Articles | Metrics

In this work the heterogenization in polymeric membranes of decatungstate, a photocatalyst for oxidation reactions, was reported. Solid state characterization techniques confirmed that the catalyst structure was preserved within the polymeric membranes. The catalytic membranes were successfully applied in the aerobic photo-oxidation of phenol, one of the main organic pollutants in wastewater, providing stable and recyclable photocatalytic systems. The dependence of the phenol degradation rate by the catalyst loading and transmembrane pressure was shown. By comparison with homogeneous reaction, the catalyst heterogenised in membrane appears to be more efficient concerning the rate of phenol photodegradation and mineralization.

Electroplating of Carbon Fibers in Sulfate Acidic Solution

CAO Zhuo-kun;LIU Yi-han;YAO Guang-chun

. 2006, 6(4): 651-655.

Asbtract ( )

PDF (763KB) ( )

Related Articles | Metrics

Carbon fibers coated with copper are widely utilized in many fields because of their special properties. In this study, carbon fibers were pretreated in both air at high temperature and HNO3 solution, and the surface change of the fibers was detected by X-ray photoelectron spectroscope (XPS). A simple electroplating technique in a sulfate bath was used. Through changing the concentrations of H2SO4 and CuSO4 and adding additive agents of 2-mecaptobenzimidazole, ethylene thiourea, 3,3-Dithiobis-1-propanesulfonic acid disodium salt, etc., uniform and smooth copper coating was obtained on carbon fibers. And the effects of H2SO4 and the additive agents on the copper coating features were examined. The copper coating was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results indicates that uniform and smooth copper coating could be obtained in the solution of CuSO4 60 g/L, H2SO4 180 g/L and addition of additive agents.

Fischer-Tropsch Synthesis over Modified Cobalt Catalysts

;WANG lei;ZHANG Xiang-ping;

. 2006, 6(4): 656-660.

Asbtract ( )

PDF (112KB) ( )

Related Articles | Metrics

The catalysts of Co/Zr-SiO2 were prepared by precipitation and the promoter of Pt was supported by impregnation. The reducibility of the cobalt oxide and the other physicochemical properties of the catalysts were characterized by TPR, TPD, BET and XPS. With the evaluation of the reduction temperature, the reduction degree increased but the surface area of the catalysts and the adsorption property for reactant CO distinctly decreased; The addition of Pt resulted in the improvement of the reducibility by decreasing the reduction temperature of cobalt oxide species. The FT-synthesis has been performed in a quartz fixed-bed reactor, and the experimental results showed that the best activity for promoted catalyst has been found at the reduction temperature of 400℃, in spite of its uncompleted reduction.

The Intermetallic Catalysts for Oxidative Esterification of Methacrolein to Methyl Methacrylate

;;;

. 2006, 6(4): 661-665.

Asbtract ( )

PDF (150KB) ( )

Related Articles | Metrics

A series of supported intermetallic Pb-Pb catalysts were prepared with the impregnation method by changing the support (silica, molecular sieve or g-alumina ) and the pore size. The chemical states of the two metals were characterized by XPS analysis, the process for producing methyl methacrylate based on the direct oxidative esterification of methacrolein with methanol in the presence of oxygen was performed in a slurry reactor with the above-mentioned catalysts. The influence of the calcination temperature and the kinds of support as well as the pore size on catalytic activity had been extensively investigated. Under the conditions of temperature at 80℃, catalyst 3.8% (w) and the reaction time 2 h, the conversion rate of methacrolein reached 85%, the selectivity and the yield of methyl methacrylate were 90% and 76.5%, respectively.

Preparation and Characterization of Melt-infiltrated Zirconia-Glass All-ceramic Dental Composite

YU Bin;ZHU Qing-shan

. 2006, 6(4): 666-669.

Asbtract ( )

PDF (299KB) ( )

Related Articles | Metrics

A glass material, based on the SiO2-B2O3-La2O3-Al2O3-Y2O3-ZrO2-CaO-BaO-TiO2 system, was successfully developed for fabricating zirconia (3Y-TZP)-glass composite through melt-infiltration process for all-ceramic dental applications. The newly developed glass meets all the design criteria for 3Y-TZP infiltration, e.g. the viscosity of the glass is low enough for spontaneous infiltration at 1100~1200℃, the glass has a coefficient of thermal expansion close to that of 3Y-TZP, the glass is chemically compatible with 3Y-TZP, etc. Consequently, zirconia-glass composite was fabricated through infiltrating the glass into 3Y-TZP performs partially sintered at 1450℃ for 2 h. Preliminary research results demonstrated that the bending strength and fracture toughness of the zirconia-glass composite were 400 MPa and 5.5 MPa×m1/2 respectively, which are respectively 32% and 41% higher as compared with the In-Ceram alumina-glass composite, tested under the same conditions.

Research on Liquid-state Reaction Synthesis and Electrochemical Property of Lithium Vanadium Oxide

LIU Li-ying;TIAN Yan-wen;ZHAI Yu-chun;XU Cha-qing

. 2006, 6(4): 670-673.

Asbtract ( )

PDF (423KB) ( )

Related Articles | Metrics

Lithium vanadium oxide was synthesized by a liquid-state reaction method. The main reaction mechanism was determined by XRD and TG-DTA analysis. Physical characteristics and electrochemical performances of Li1+xV3O8 were investigated by XRD, SEM, galvanostatic charge-discharge and cyclic voltammogram tests. The results indicated that the as-synthesized material had pure layered structure and was evengranular. A maximum reversible capacity of 288.9 mA×h/g for the first cycle and 264.0 mA×h/g after 15 cycles were obtained and charge-discharge efficiency was above 93.84%. Insertion of Li＋ in Li1+xV3O8 proceeded step by step.

Research Advances in Immunomodulation and Antitumor Activity of Polysaccharides

WANG Tong-yi;ZHAO Bing;WANG Yu-chun

. 2006, 6(4): 674-682.

Asbtract ( )

PDF (515KB) ( )

Related Articles | Metrics

Enhancing immunity and antitumor activity is the important biological activity of polysaccharide. Studies showed that it enhanced immunity through improving the activity of immunocyte, activising the secretion of cell factor, inducing the production of antibody and activising the complementary system, etc. The antitumor ways of polysaccharide mainly were inhibiting the growth of cancer cells and the synthesis of protein and nuclear acid in the cells, inducing apoptosis, affecting the expression of cancer gene and changing the growing specialities of the cancer cell membrane. In this review, research advances in the field of immunomodulation and antitumor activity of polysaccharides in recent years were briefly summarized and analysed.

An Analysis of Contemporary Copper Recycling in China

YUE Qiang;LU Zhong-wu

. 2006, 6(4): 683-690.

Asbtract ( )

PDF (183KB) ( )

Related Articles | Metrics

Copper consumption increased very quickly in China in recent years, which could not be met by inland copper industry. In order to achieve a sustainable development of copper industry, an analysis of copper recycling in China was necessary. For the life cycle of copper products a copper-flow diagram with time factor was worked out and the contemporary copper recycling in China was analyzed, from which the following data were obtained. The average life cycle of copper products was 30 years. From 1998 to 2002, the use ratio of copper scraps in copper production, the use ratio of copper scraps in copper manufacture, the materials self-support ratio in copper production, and the materials self-support ratio in copper manufacture were 26.50%, 15.49%, 48.05% and 59.41%, respectively. The materials self-support ratios in copper production and manufacture declined year by year in recent years on the whole, and the latter dropped more quickly. The average index of copper ore and copper scrap from 1998 to 2002 were 0.8475 t/t and 0.0736 t/t, respectively; and copper resource efficiency was 1.1855 t/t. Some efforts should be paid to reduce copper ores consumption and promote copper scraps regeneration. Copper scraps were mostly imported from foreign countries because of shortage in recent years in China. Here the reasons related to copper scraps deficiency were also demonstrated. But we can forecast: when copper production was in a slow rise or in a steady state in China, the deficiency of copper scraps may be mitigated; when copper production was in a steady state for a very long time, copper scraps may become relatively abundant. According to the status of copper industry in China, the raw materials of copper production and manufacture have to depend on oversea markets heavily in recent years, and at the same time, the copper scraps using proportion and efficiency in copper industry should be improved.

Effluent Zero Release Concept?The Brazilian Experience

;

. 2006, 6(4): 691-696.

Asbtract ( )

PDF (94KB) ( )

Related Articles | Metrics

Water scarcity is pushing the government, industries and researchers to the development of new strategies for water and wastewater management. An approach aimed at the optimization of the water use and minimization of effluent generation was developed at the Centro Experimental ARAMAR (CEA), a nuclear research facility, located in the State of Sao Paulo, Brazil. Bench scale tests followed by a pilot plant treating effluents from some nuclear research facilities have shown the results leading to the conclusion that the effluent zero release concept is feasible. Based on the gathered data, a project of an integrated effluent treatment system focusing on water recovery and environmental effluent release reduction has been developed.

Table of Content