Please wait a minute...
Table of Content
05 February 2018, Volume 69 Issue 2
    Research progress on graphene oxide composite hydrogels
    SHAN Guorong, ZHANG Ning
    2018, 69(2):  535-545.  doi:10.11949/j.issn.0438-1157.20170947
    Abstract ( 581 )   PDF (14231KB) ( 796 )  
    References | Related Articles | Metrics

    Graphene oxide (GO) is a kind of two-dimensional nanomaterial, which is cheap, easy to disperse in water, able to response to near infrared (NIR) light and has good thermal performance. The introduction of graphene oxide endows hydrogels with varieties of excellent properties of nanomaterials, thus greatly broadens the potential application of hydrogels. In this paper, graphene oxide composite hydrogels with excellent mechanical properties, superior thermal conductivity to absorb NIR, self-healing ability and its application in the smart actuators and cell scaffolds are introduced in detail. The direction of its future research and prospect are put forward.

    Research progress of microbial fuel cell for treating high salinity wastewater
    CHENG Shao'an, HUANG Zhipeng, YU Liliang, MAO Zhengzhong, HUANG Haobing, SUN Yi
    2018, 69(2):  546-554.  doi:10.11949/j.issn.0438-1157.20171384
    Abstract ( 605 )   PDF (489KB) ( 642 )  
    References | Related Articles | Metrics

    Treating high salinity wastewater by using common methods like biochemical methods, evaporation and membrane treatment is difficult and costly. Microbial fuel cell (MFC) is a device for converting chemical energy into electrical energy using electricigens as the catalysts. Application of MFC in wastewater treatment could lower the treatment cost due to additional electricity generation during the wastewater treatment. In recent years, using MFC to treat high salinity wastewater for lowering the treatment cost has been tested and gradually become a hot spot. The aim of this paper is to review the latest research progress of MFC for treating high salinity wastewater. The effects of salinity on electricity generation, pollutant removal, growth and community of microorganisms of MFC were summarized. The future research works of MFC for high salinity wastewater treatment are proposed on salt-tolerant microorganisms, biofilm, the reactor structure and extended applications.

    Interaction between supercritial carbon dioxide-cosolvent and poly(vinyl acetate)
    HU Dongdong, BAO Lei, LIU Tao, LANG Meidong, ZHAO Ling
    2018, 69(2):  555-562.  doi:10.11949/j.issn.0438-1157.20170900
    Abstract ( 353 )   PDF (2465KB) ( 379 )  
    References | Related Articles | Metrics

    The effect of cosolvents (ethanol, acetone, n-heptane) on the supercritical CO2 system were evaluated through the multi-scale molecular modeling and dissolution behavior measurement, which might improve the solvent-solvent and solvent-solute interactions and enhance the compatibility with polymer. The ab initio calculation showed that the interaction between ethanol and CO2 was the strongest one, followed by that of acetone and n-heptane. The molecular dynamics simulations indicated that ethanol significantly increased the solubility parameter of solvent, and the interaction of supercritical CO2-ethanol with PVAc chain was stronger than that of the other two at the same co-solvent content, which was helpful to improve the compatibility between PVAc and the solvent. The interaction between ethanol and CO2 was the strongest due to the bigger solubility parameter of ethanol and the obvious hydrogen bond between ethanol and CO2.The cloud point experiments confirmed that ethanol was the most effective to reduce the cloud point pressure of PVAc. The addition of cosolvent enhanced the compatibility of supercritical CO2 system with PVAc, and the solubility of PVAc in supercritical CO2-cosolvent increased with the mole fraction of cosolvent.

    Kinetics of acrylamide and 2-methylacryloylxyethyltrimethyl ammonium chloride in inverse emulsion polymerization
    CHEN Yong, SHAN Guorong
    2018, 69(2):  563-569.  doi:10.11949/j.issn.0438-1157.20170870
    Abstract ( 364 )   PDF (575KB) ( 301 )  
    References | Related Articles | Metrics

    Inverse emulsion polymerization kinetics of acrylamide (AM) and 2-methylacryloylxyethyltrimethyl ammonium chloride (DMC) has been investigated by using the mixture of sorbitan monooleate (Span 80) and polyethylene glycol sorbitan monooleate (Tween 80) as the composite emulsifier, liquid paraffin as the oil phase and 2,2'-azobis[2-(2-imidazolin-2-yl) propane]-dihydrochloride as the initiator. The rate equation of AM and DMC inverse emulsion polymerization could be represented as Rp=k[M]2.12[I]0.55[E]0.65, and the apparent activation energy of AM and DMC inverse emulsion polymerization was 80.65 kJ·mol-1. Relationship of reaction rate change in AM and DMC inverse emulsion polymerization with time indicated that the nucleation mechanism tended to droplet nucleation. Monomer reactivity ratios of AM and DMC were determined as rAM=0.23,rDMC=1.93 by Fineman-Ross methods. The results showed that random copolymerization of AM and DMC occurred on the polymer chains. The intrinsic viscosity of copolymer could be increased by enhancing the content of monomer, decreasing the dose of initiator, increasing the amount of emulsifier and reducing the reaction temperature.

    Effect of binary solvent mixtures on stability and morphology of thiamine hydrochloride solvate
    YANG Yang, WANG Haisheng, LIU Yumin, HAN Dandan, WANG Jingkang, GONG Junbo
    2018, 69(2):  570-577.  doi:10.11949/j.issn.0438-1157.20170774
    Abstract ( 331 )   PDF (1480KB) ( 333 )  
    References | Related Articles | Metrics

    Vitamin B1 is one of the most essential nutrients in human bodies. Thiamine hydrochloride, a form of vitamin B1, has four solvates, hemihydrate (HH), methanol solvates (MM), nonstoichiometric hydrate (NSH), and anhydrous form (AH). These four solvates have different stabilities because of different space structures. In that way, a stable solvate which has better properties of production, storage and transportation is investigated by drug industry. In this paper, X-ray diffraction and thermal analysis were measured and crystal form transformation experiments in methanol-water and methanol-ethyl acetate were investigated. It can be seen that hydrate hemihydrate is more stable because of hydrogen bonds. Moreover, molecular dynamics simulation by using BFDH and AE model of MM in methanol-ethyl acetate binary solvent mixtures was calculated. The result shows that BFDH model matches real crystal habit, which could guide industrial production.

    Measurement and correlation of vapor-liquid equilibrium for ternary system of n-butanol-chlorobenzene-acetophenone
    FAN Kai, CHEN Changxu, ZHOU Feng, ZHENG Hui, XU Chunjian
    2018, 69(2):  578-585.  doi:10.11949/j.issn.0438-1157.20170804
    Abstract ( 432 )   PDF (515KB) ( 261 )  
    References | Related Articles | Metrics

    The influence of six different solvents on the relative volatility of n-butanol and chlorobenzene system was investigated, which shows that acetophenone has a better performance in this minimum azeotrope system. Isobaric vapor-liquid equilibrium (VLE) data for binary systems of n-butanol-chlorobenzene, n-butanol-acetophenone, chlorobenzene-acetophenone and ternary system of n-butanol-chlorobenzene-acetophenone at 101.33 kPa were measured by using a vapor-liquid equilibrium still. And then, all of the measured VLE values were checked by the area method proposed by Herington and the point-to-point method of Van Ness. Furthermore, the VLE data were correlated by Wilson, NRTL and UNIQUAC activity coefficient, respectively. The binary interaction parameters were used to predict the ternary VLE behavior, which fit with the experimental data. The experimental results indicate that the relative volatility between n-butanol chlorobenzene is changed obviously by adding acetophenone as a solvent at 0.50 mass fraction, which shows that acetophenone is a promising solvent for the separation of the n-butanol and chlorobenzene mixture in extractive distillation. This work provides important engineering data for chemical database and further study in the engineering design.

    Simultaneous PIV/LIF measurements of interfacial convection during CO2 dissolution in water and prediction of mass transfer coefficient
    FU Qiang, ZHANG Huishu, HU Nan, YUAN Xigang, YU Kuotsung
    2018, 69(2):  586-594.  doi:10.11949/j.issn.0438-1157.20171043
    Abstract ( 412 )   PDF (4571KB) ( 324 )  
    References | Related Articles | Metrics

    Liquid phase velocity fields and concentration distributions in an interfacial Rayleigh convection process during CO2 dissolution in water were simultaneously measured by combining particle image velocimetry (PIV) and laser induced fluorescence (LIF) technique. The evolution of Rayleigh convection was investigated quantitatively. Through the analysis of the mass transfer in the interfacial convection process, it is found that the vorticity is a major factor affecting the liquid mass transfer coefficient for the Rayleigh convection process. The relationship between the vorticity and the mass transfer coefficient was obtained, and a correlation was established. An effective method to predict liquid mass transfer coefficient by measuring velocity fields was established for the processes with Rayleigh convection.

    Experimental research of R1234yf transient spray cooling and influence of cryogen superheat degree
    WANG Rui, CHEN Bin, WANG Jiafeng, TIAN Jiameng, ZHOU Zhifu, YING Zhaoxia
    2018, 69(2):  595-601.  doi:10.11949/j.issn.0438-1157.20171094
    Abstract ( 357 )   PDF (1953KB) ( 245 )  
    References | Related Articles | Metrics

    Cryogen spray cooling is a significant assistance to clinical laser therapy. R134a and R404A are currently used in clinical application and experimental research, which both have extremely high global warming potential (GWP) and serious threat to the environment. An exploratory research was conducted on spray cooling by using R1234yf as an alternative cryogen in clinical application due to its similar properties with R134a and low GWP value. The experimental result on surface heat transfer shows its cooling capacity a little worse than R134a and R404A. The concentration of the spray can be effectively enhanced by reducing the superheat degree, and the surface heat flux can be also enhanced on the premise of flashing atomization, which improves the feasibility of R1234yf spray cooling in clinical application.

    Formation and manipulation of ferrofluid droplets in Y-shaped flow-focusing microchannel
    MA Rui, FU Taotao, ZHANG Qindan, LIU Cai, ZHU Chunying, MA Youguang
    2018, 69(2):  602-610.  doi:10.11949/j.issn.0438-1157.20170938
    Abstract ( 253 )   PDF (1944KB) ( 305 )  
    References | Related Articles | Metrics

    With high-speed camera, formation of ferrofluid droplets in mineral oil was studied in a Y-shaped microchannel with cross section of 400 μm×400 μm. In the system of water-based ferrofluid (EMG 807) as dispersed phase and mineral oil with 4%(mass) surfactant sorbitan lauric acid ester (Span-20) as continuous phase, three types of flow regimes were observed, i.e., slug, dripping and jetting flows. Study of two-phase flow rates, capillary number of continuous phase and magnetic flux density on droplet size and formation process showed that both two-phase flow rates and magnetic field could regulate droplet size. At constant flow rate of the dispersed phase, droplet size decreased with increasing ratio of two-phase flow rates. The droplet size decreased with the increase of capillary number of continuous phase and magnetic flux density, but increased along with the increase of flow rate of the dispersed phase. A correlation of droplet size was proposed on parameters of two-phase flow rates, capillary number of continuous phase, and magnetic Bond number, which offered accurate prediction with experimental data.

    On-line measurement of coal powder size distribution using digital holography
    ZHAO Liang, WU Chenyue, LIN Xiaodan, WU Yingchun, WU Xuecheng, ZHOU Yonggang, QIU Kunzan, CEN Kefa
    2018, 69(2):  611-617.  doi:10.11949/j.issn.0438-1157.20171242
    Abstract ( 315 )   PDF (1707KB) ( 483 )  
    References | Related Articles | Metrics

    Particle size distribution of coal powder is one of the most important indexes which contribute a lot to energy conservation and emission reduction of power plant. Digital holography is applied to measure the particle size distribution on a set of device stimulating the actual working conditions of coal supply system of power station. The results show that the distribution curve measured by digital holography has the similar trend with the curve measured by laser particle size analyzer. The relative error between the average diameters is 5.6%. The relative errors between the d50 and d90, are less than 2% which is in the allowable range. The relative errors between before and after the dilution is lower than 7%. The trends of particle size distribution curve of the same sample are consistent in different conditions. The reliability of digital holography for on-line measurement of pulverized coal particle size distribution is verified, which lays a foundation for the development of the overall measurement instrument.

    Chaotic mixing performance in rigid-flexible impeller stirred tank with eccentric air jet
    QIU Facheng, LIU Zuohua, LIU Renlong, QUAN Xuejun, CHEN Jiaxing, GU Deyin, LI Bing, WANG Yundong
    2018, 69(2):  618-624.  doi:10.11949/j.issn.0438-1157.20171041
    Abstract ( 348 )   PDF (935KB) ( 208 )  
    References | Related Articles | Metrics

    Isolated mixing regions exist widely in the stirred tank, which is a major obstacle for efficient mixing. In order to increase the mixing efficiency, the method of multiple flow fields coupling, which can bring out fluid chaos, is used to increase fluid mixing efficiency by reducing the isolated mixing regions. The largest Lyapunov exponent and multi-scale entropy are investigated with the aid of Matlab in the coupling of eccentric air jet and rigid-flexible combined impeller system. Meanwhile, the effects of impeller types, impeller off-bottom clearances, air jet flow rates, and the impeller speeds on the mixing performance are analyzed at different eccentricities. The results show that the flow field coupling of the rigid-soft-flow of multi-body motion of rigid-flexible combined impeller and eccentric air jet destroy the symmetry flow in the process of fluid mixing and made more fluid into the chaotic state. The LLE of rigid-flexible combined impeller is larger than that of rigid impeller. The LLE of rigid-flexible combined impeller compared with the other three types agitators (IRDT, RDT, RF-IRDT) increases 42.8%, 27.0%, and 6.9%. When the eccentricity of the air jet is equal to 0.6, the maximum LLE value is 6.5%, 2.4%, 17.6% and 25.1% which is higher than the other eccentricity (0.8, 0.4, 0.2, 0). The results of this study can provide the theoretical basis for the optimal design of rigid-flexible agitator.

    Chaotic mixing and dispersing characteristics of gas-liquid two phases in stirred tank
    GU Deyin, LIU Zuohua, ZHANG Jiyizhe, QIU Facheng, LI Jun, TAO Changyuan, WANG Yundong
    2018, 69(2):  625-632.  doi:10.11949/j.issn.0438-1157.20171208
    Abstract ( 418 )   PDF (786KB) ( 261 )  
    References | Related Articles | Metrics

    Traditional Rushton rigid impeller is often applied to gas-liquid dispersion process in industrial stirred tank reactors. However, poor gas dispersion capacity is occurred behind impeller blades due to easy formation of gas cavitation. In order to improve gas-liquid mixing performance, a rigid-flexible impeller was proposed to intensify gas dispersion process. Time series data of pressure fluctuation were recorded by LabVIEW and the largest Lyapunov exponent (LLE) was calculated by Matlab to analyze chaotic characteristics of gas-liquid mixing behavior, while relative power demand, total gas holdup, and local gas holdup were measured simultaneously in stirred tank with a rigid impeller or a rigid-flexible impeller. Results showed that, under condition of power consumption at 170 W and gas flowrate at 10 m3·h-1, rigid-flexible impeller could strengthen energy transfer and enhance chaotic mixing through rigid-flexible-flow interaction. LLE value of rigid-flexible impeller system was 8.89% higher than that of rigid impeller system. Rigid-flexible impeller could improve relative power demand, total gas holdup, local gas holdup, and more homogeneously gas dispersion, compared to rigid impeller at the same operating conditions.

    Characterization of pore structure and effective thermal conductivity of iron ore sinter using micro CT images
    ZHOU Mingxi, ZHOU Hao, MA Pengnan, CHENG Ming
    2018, 69(2):  633-641.  doi:10.11949/j.issn.0438-1157.20171233
    Abstract ( 286 )   PDF (5349KB) ( 225 )  
    References | Related Articles | Metrics

    Understanding of the thermophysical properties of porous sinter is especially important for operation optimization and energy saving in integrated steel mills. Under this prospect, nondestructive X-ray microtomography was applied to characterize the pore structure and the simulations for estimating the sinter effective thermal conductivity were performed. Three sinter cakes produced from pilot-scale sinter pot tests under three hydrated lime addition levels were scanned with resolution ratio of 40 μm. The reconstructed sinter cakes have various complex pore distributions, leading to remarkable anisotropic thermal conductivities and complicated temperature field. The pores smaller than 300 μm dominate the number frequency in sinter cake (around 45%-50%), while a small amount of pores larger than 1 mm account for around 95% of the total pore volume, which determines the thermal behavior greatly. The estimated effective thermal conductivities of three samples are 0.645, 0.682, and 0.784 W·m-1·K-1, corresponding to the porosity of 53.8%, 53.1% and 49.7% respectively. Comparing these values with values of similar iron agglomerates in the literature, some empirical correlations and analytical models, the results proved that CT-simulation is a valid approach for capturing the peculiar details of the real sinter porous structure, thus to predict thermal behavior with higher accuracy than the simplified geometric models.

    Flow and mass-transfer model of new countercurrent gas-liquid scrubber
    MAN Changzhuo, FAN Yiping, FAN Hanwen
    2018, 69(2):  642-649.  doi:10.11949/j.issn.0438-1157.20170655
    Abstract ( 384 )   PDF (1838KB) ( 227 )  
    References | Related Articles | Metrics

    The flow-mass transfer characteristics of a new countercurrent gas-liquid scrubber were investigated through cold model experiment. The results indicated that different gas-liquid flow patterns in the scrubber could be obtained under different operating conditions. Both the volume of the highly efficient mass-transfer and the desorption rate under the bubble flow presented the higher values comparing with those under other two flow patterns. Combining the experimental results with theoretical analysis, a two-zone flow-mass transfer model which can estimate the mass-transfer of the scrubber was established based on its characteristics of rapid renewal on gas-liquid surface and highly turbulent bubble flow. The structural/operating features of the scrubber were also considered. The proposed model divided the whole gas-liquid impinging area into two zones, including the rotating jet-flow zone and the high-efficiency mass-transfer zone. Then the relationships of desorption rate to L/G as well as ω were discussed by using the model. The computed results by this model match well with the experimental under different operating conditions and it can be used for engineering design purpose.

    Bubble forming dynamics of highly viscous fluids in microfluidic flow-focusing cross channel device
    ZHANG Chong, FU Taotao, JIANG Shaokun, ZHU Chunying, MA Youguang
    2018, 69(2):  650-654.  doi:10.11949/j.issn.0438-1157.20170968
    Abstract ( 423 )   PDF (1904KB) ( 345 )  
    References | Related Articles | Metrics

    N2 bubble formation in highly viscous (630 mPa·s) glycerol-water solution in a microfluidic flow-focusing cross channel device was observed by using a high-speed camera. Bubble forming process, size, and minimal neck radius were studied. The results show that the bubble formation process can be divided into stages of retraction, expansion, collapse, and final breakup. The bubble size was increased linearly with time in both expansion and collapse stages, which the slope in the collapse stage was greater than that in the expansion stage. The decrease of minimal neck radius of bubbles against time was different in two stages, i.e., a power-law to remaining time in the collapse stage and a linearity with time in the final breakup stage.

    Jet characteristics of nozzle of pipe grid gas distributor in FCC regenerator
    SHI Ruijie, WANG Chuangbo, MA Ling, YAN Chaoyu, WEI Yaodong
    2018, 69(2):  655-663.  doi:10.11949/j.issn.0438-1157.20170999
    Abstract ( 355 )   PDF (8244KB) ( 238 )  
    References | Related Articles | Metrics

    In the catalytic cracking unit, the bottom of the regenerator is equipped with a pipe grid gas distributor. The gas is distributed into the regenerator bed through the nozzles on the distributor. In the actual operation, there will be problems of uneven distribution of gas and a serious erosion wear phenomenon in the distributor, and they have influences on the distribution effect and life of the distributors. The study on the jet characteristics of the nozzle was carried out in a two-dimensional bed experimental device. The solid material used in the experiment is FCC catalyst particles. In the experiment, the gas flow velocity through the nozzles ranged from 30 m·s-1 to 70 m·s-1, and the jet angle of the nozzles was in the range of 0°-67.5°. The jet length of the nozzles and the flow field of the bed near the nozzle were recorded by photogrammetry. The results show that the jet length increases with increasing the nozzle gas velocity and the nozzle angle. During the process when jet gas is turned upwards, swirl vortex appears in the upper part between the two branch pipes. The swirl vortex has a great relationship to the gas velocity and the jet angle. The size of the vortex is related to the size of the dilute phase space. Finally, based on the experimental data, a calculation model about the nozzle jet length was established.

    Kinetic modeling of ethylene polymerization with Cr-V bimetallic catalyst
    LIU Bao, TIAN Zhou, ZHAO Ning, LIU Boping
    2018, 69(2):  664-673.  doi:10.11949/j.issn.0438-1157.20171035
    Abstract ( 315 )   PDF (800KB) ( 312 )  
    References | Related Articles | Metrics

    Bimetallic catalyst has been a hot research topic as it can realize one-pot synthesis of polyethylene with bimodal molecular weight distribution (MWD). The kinetics of ethylene homopolymerization with a novel Cr-iV bimetallic catalyst and corresponding monometallic S-2 and iV catalyst were studied at various experimental conditions. MWD deconvolution of polymers made by these catalysts showed interaction between Cr and V active centers in the Cr-iV bimetallic catalyst, reduced the activity of Cr centers, while activity of V centers was improved. Polymerization temperature almost did not change mass fractions of polymers produced by two active centers. The simplified single-center kinetic model for ethylene homopolymerization was employed to describe polymerization behaviors of Cr and V centers in Cr-iV bimetallic catalyst. Kinetic parameters of each active center were estimated by fitting experimental results of polymerization rates with model prediction. Compared to monometallic catalyst, Cr center in the Cr-iV catalyst had decreased chain propagation rate constant, which lead to reduction of polymerization activity, whereas V center in the Cr-iV catalyst had decreased chain deactivation rate constant, which signified more stable and active V center.

    Microkinetic analysis of acetylene hydrogenation over Pd-Ag/Al2O3 catalyst with different Pd/Ag ratios
    ZHANG Jian, HUANG Bangyin, SUI Zhijun, ZHOU Xinggui, YUAN Weikang
    2018, 69(2):  674-681.  doi:10.11949/j.issn.0438-1157.20171007
    Abstract ( 322 )   PDF (3161KB) ( 297 )  
    References | Related Articles | Metrics

    Selective acetylene hydrogenation is an important purifying reaction in ethylene industry. Pd-Ag/α-Al2O3 catalysts with different Pd/Ag ratios were prepared by stepwise incipient wetness impregnation method and characterized for structure and composition by N2-physisorption,XRD,ICP,XPS,TEM and CO chemisorption. A microkinetic model of acetylene hydrogenation over these catalysts was established from a fractional factorial design of experiment and effects of Ag amount on the hydrogenation kinetics were analyzed through microkinetic simulation and parameter value change. After values for basic parameters used DFT calculation results of C2 hydrogenation over Pt-Ag catalysts and activation energies optimized by adsorption-desorption steps, the microkinetic model could fit kinetic experiment results quite well on acetylene hydrogenation over all catalysts of various Pt-Ag ratios. The study showed that C2H4* was the most abundant surface species and vinyl hydrogenation was rate control step, which did not change with increase of Ag content. However, the increase of Ag greatly reduced activation energy of hydrogen desorption and improved ethylene selectivity. This phenomenon might be correlated to enhancement of electron transfer from Ag to Pd on the catalyst surface upon increase of Ag content.

    Effect of ceramic matrices on dispersion of loaded catalyst and DeNOx activity of catalytic filters
    YU Chao, LI Changming, ZHANG Yusheng, GUO Feng, YU Jian, YANG Yunquan, XU Guangwen
    2018, 69(2):  682-689.  doi:10.11949/j.issn.0438-1157.20170939
    Abstract ( 359 )   PDF (5286KB) ( 335 )  
    References | Related Articles | Metrics

    There is a wide application prospect for the development of a catalytic filter with simultaneous DeNOx and de-dust function in the DeNOx treatment of flue gas from small furnace. Three kinds of typical commercial ceramic filters were used to prepare catalytic DeNOx filters by coating method, and their catalytic performance were investigated on different flue gas condition. The XRD, XRF, SEM and MIP results demonstrate that the ceramic filter with little alkali/alkaline earth metal and uniform pore distribution will promote the dispersion and DeNOx activity of the catalytic particles as well as the decreased pressure drop. The NO conversion can be above 90% in the temperature range of 220-380℃ (face velocity=1 m·min-1, NH3/NO=1), and the NO conversion can still maintain above 90% after introduction of H2O (15%, vol) and SO2 (3×10-2%, vol) in the temperature range of 260-450℃. The excellent DeNOx performance of the catalytic filter meets well the demands of practical industrial application.

    Activation atmospheres on structure-performance relationship of K-promoted Fe catalysts for lower olefin synthesis from CO2 hydrogenation
    ZHANG Yulong, SHAO Guangyin, ZHANG Zhengpai, LIU Xianglin, ZHANG Chao, XU Jing, HAN Yifan
    2018, 69(2):  690-698.  doi:10.11949/j.issn.0438-1157.20170995
    Abstract ( 329 )   PDF (724KB) ( 303 )  
    References | Related Articles | Metrics

    Lower olefins synthesis from direct CO2 hydrogenation over Fe-based catalysts is an important process of CO2 utilization. Iron catalysts with different K loading (1%, 3%, 5%, 7% and 9%) prepared by thermal decomposition were used in CO2 hydrogenation. Fe95-K5 (95%Fe-5%K,mass fraction) catalyst showed the highest activity and C2-C4 olefin selectivity. Further enhancement on Fe95-K5 catalytic performance was achieved by pre-treatment under three different activation atmospheres (10%H2/Ar, 10%CO/Ar, 5%CO/5%H2/Ar) prior to CO2 hydrogenation. 10%CO/Ar-activated catalyst showed the highest C2-C4 olefin selectivity (38.1%) and chain growth probability (α=0.644). In addition, the structure evolution of Fe95-K5 during activation and CO2 hydrogenation was characterized by X-rays diffraction (XRD), Raman and temperature-programmed hydrogenation (TPH) techniques. CO introduction in pretreat process accelerated formation of iron carbides. γ1-iron carbide was formed after pretreating in 10%CO/Ar and 5%CO/5%H2/Ar, while γ2-iron carbide was produced in the hydrogenation reaction after pretreating in 10%H2/Ar. Both carbides could promote CO2 dissociation on catalyst surface.

    Iron-based catalyst on PANI-derived N-containing carbon carriers: effect of carrier carbonization temperature on direct syngas conversion to light olefins
    SHI Bianfang, ZHA Binbin, ZHANG Jun, ZHANG Zhengpai, XU Jing, HAN Yifan
    2018, 69(2):  699-708.  doi:10.11949/j.issn.0438-1157.20170996
    Abstract ( 273 )   PDF (1336KB) ( 290 )  
    References | Related Articles | Metrics

    Light olefins are key building blocks for production of many chemical intermediates and polymers in chemical industry, which makes strategically important to produce light olefins directly from non-petroleum syngas resources. It has been found that catalyst carriers significantly affect catalyst performance in CO hydrogenation. A series of Fe-based catalysts on PANI-derived N-containing carbon material, prepared by incipient wetness impregnation at various carbonization temperature, were used to study carbonization temperature on catalytic performance. With the increase of carbonization temperature, both light olefin selectivity and O/P ratio were increased. Fe20/NC-800 catalyst had the highest light olefin selectivity of 41.05%. Catalyst characterization by scanning electron microscope, Raman spectrum and X-ray photoelectron spectrum showed that carbonization temperature increase didn't change carrier structure much, but improved degree of graphitization and decreased total nitrogen content and amount of quaternary nitrogen species. It was also found that amount of pyridinic nitrogen was improved but amount of pyrrole nitrogen species was slightly dropped first and then increased with the increase of carbonization temperature. Moreover, XPS and in situ XRD analysis on surface and bulk structures of catalysts showed that carbonization temperature increase reduced number of high binding energy N species on carrier surface, strengthened electron donating effect on iron, and weakened metal-carrier interaction, which promoted reduction, carbonization and agglomeration of active metal iron and finally enhanced yield of light olefins.

    Reaction network and thermodynamic equilibrium for tetralin hydrocracking over NiMo/HY catalyst
    CHEN Junsen, PENG Chong, FANG Xiangchen, ZHOU Zhiming
    2018, 69(2):  709-717.  doi:10.11949/j.issn.0438-1157.20171034
    Abstract ( 343 )   PDF (811KB) ( 329 )  
    References | Related Articles | Metrics

    Tetralin hydrocracking over a commercial catalyst NiMo/HY was carried out to study temperature effect on product distribution in a laboratory-scale fixed-bed reactor. Based on the experimental results, a reaction network for tetralin hydrocracking was proposed, which contained 12 reactions with different types such as hydrogenation, isomerization, dehydrogenation, ring opening and dealkylation. Thermodynamic equilibrium calculations provided equilibrium constants for all reactions in the network, equilibrium yields of different products as well as yield variations with temperature, pressure and molar ratio of H2 to tetralin. Thermodynamic calculation of product yield changes with operating conditions was generally in agreement with those of experiments, demonstrating that the reaction network depicted well for tetralin hydrocracking over NiMo/HY catalyst system.

    Influence of mixing inside microreactor on microstructural evolution of Cu-ZnO catalyst
    LING Chen, JIANG Xin, WANG Zhiyong, QIN Xiangfei, LU Jiangang
    2018, 69(2):  718-724.  doi:10.11949/j.issn.0438-1157.20170976
    Abstract ( 283 )   PDF (1510KB) ( 521 )  
    References | Related Articles | Metrics

    The influence of mixing inside the microreactor on the microstructural evolution of Cu-ZnO catalyst was investigated by regulating the flow rate. Mixing efficiency in the microreactor was measured by Villermaux-Dushman reaction system under different flow rates, and the structures of precursor and oxide were characterized by X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that with increase of the mixing intensity, the distribution of Cu2+ and Zn2+ in precursor becomes more uniform, the fraction of aurichalcite decreases and Zn content in zincian malachite rises. The difference in the precursors acts on the oxides, leading to a more uniform Cu-Zn distribution, a better dispersion between CuO and ZnO, and the decrease of CuO size. Above study reveals, it is by the Cu-Zn distribution that the changes of mixing during the precipitation affects the subsequent product and results in the difference in Cu-ZnO catalyst microstructure.

    Influence of Brønsted acid strength on conversion of carbenium ion by molecular simulation
    FU Jia, FENG Xiang, LIU Yibin, YANG Chaohe
    2018, 69(2):  725-732.  doi:10.11949/j.issn.0438-1157.20170962
    Abstract ( 261 )   PDF (2103KB) ( 483 )  
    References | Related Articles | Metrics

    The influence of Brønsted acid strength on catalytic reactivity of carbenium ion was systematically studied by density functional theory (DFT) calculations. Four typical reactions of C4 carbenium ion as model compound, including hydrogen transfer, isomerization, β scission, and dehydrogenation, were simulated in five solid acid models with various acid strengths from weak-, strong-, even close to super-acid. The calculation results revealed that the reaction energy barrier decreased exponentially for hydrogen transfer reaction but decreased linearly for other three reactions with the increase of Brønsted acid strength. In weak-acid range, the sensitivities of reactions to acid strength from high to low was:hydrogen transfer > isomerization > β scission > dehydrogenation. Hydrogen transfer reaction had the lowest sensitivity in the strong-acid range. Calculation on ionic character of the organic fragments in transition states showed that reaction sensitivity to acid strength could be related to Mulliken charges of the transition state. The transition state with more Mulliken charge lead to stronger interaction with acid such that the activation energy barrier could be effectively reduced by increasing acid strength. The calculation was consistent with experimental conclusion and explained acid strength on production yield at the atomic level, which is of great significance to the development of new catalytic materials and modification of current catalysts.

    Separation performance of CO2/CH4 on porous carbons derived from glucose
    WANG Li, WANG Xingjie, LI Hao, CHEN Yongwei, LI Zhong
    2018, 69(2):  733-740.  doi:10.11949/j.issn.0438-1157.20171368
    Abstract ( 288 )   PDF (1690KB) ( 292 )  
    References | Related Articles | Metrics

    A series of glucose-based porous carbons (C-GLCs-800) were developed by simple carbonization and KOH activation, and characterized by scanning emission microscopy (SEM), nitrogen sorption, Fourier transformed infrared (FI-TR) and thermogravimetric analysis (TGA). Pure component adsorption isotherms of CO2 and CH4 were measured separately at 288, 298, and 308 K. The ideal adsorbed solution theory (IAST) model was used to estimate adsorption selectivity of the samples for CO2/CH4 binary mixtures. Results showed that the specific surface area and total pore volume of C-GLCs-800 increased at first and then decreased with the ratio of KOH/C at which the samples were activated. The BET surface area and total pore volume of C-GLC-800-4 reached as high as 3153 m2·g-1 of 2.056 cm3·g-1, respectively. The narrow micropores voulme of C-GLC-800-2 reached as high as 0.3538 cm3·g-1. The C-GLC-800-2 exhibited an extraordinary CO2 adsorption capacity of 3.96 mmol·g-1 at 298 K under 105 Pa, which was comparable to many traditional adsorbents and MOFs. The isosteric heats of CO2 adsorption on C-GLC-800-2 was higher than that of CH4. The IAST-predicted CO2/CH4 selectivity was about 8.35.

    Biogas upgrading by vacuum pressure swing adsorption process
    TIAN Caixia, SHEN Yuanhui, ZHANG Donghui, GAN Hainan
    2018, 69(2):  741-749.  doi:10.11949/j.issn.0438-1157.20170821
    Abstract ( 358 )   PDF (2276KB) ( 498 )  
    References | Related Articles | Metrics

    The carbon molecular sieve was adopted as adsorbent for biogas upgrading, and the morphologies of carbon molecular sieve were examined by scanning electron microscopy while the pore-size distribution was characterized by CO2 adsorption at 273.15 K. With the volume method, the adsorption isotherms of carbon dioxide and methane on carbon molecular sieve were measured at 283.15, 303.15, and 323.15 K and at pressure up to 0.5 MPa, while the diffusion coefficient of carbon dioxide and methane on carbon molecular sieve were also determined. The breakthrough experiments were implemented on single fixed bed, and the effects of adsorption pressure and feed flow rate on the breakthrough curve of CO2 were explored. Two-bed-six-step vacuum pressure swing adsorption (VPSA) process was carry out with the adsorption pressure of 0.3 MPa and the feed flow rate of 4 L·min-1. In addition, the effects of adsorption step time and product flush ratio on separation performances were also investigated. The experimental results show that the purity of methane could be achieved to 98% with a recovery of 82% when adsorption time was set to be 140 s with a product flush ratio of 0.05.

    Simulation and control of vacuum pressure swing adsorption for N2/CH4 separation
    HAN Zhiyang, DING Zhaoyang, HAN Yangyuan, SHEN Yuanhui, ZHANG Donghui
    2018, 69(2):  750-758.  doi:10.11949/j.issn.0438-1157.20171015
    Abstract ( 304 )   PDF (601KB) ( 395 )  
    References | Related Articles | Metrics

    The research conducted the experiments for N2/CH4 separation using the vacuum pressure swing adsorption (VPSA) process based on the two-bed experimental set-up and the laboratory-made activated carbon as adsorbent. The mathematical models were built in gPROMS and the accuracy of models was verified by comparison of simulations and experiments. The simulation results showed that the two-bed VPSA process can obtain a rich-methane product with 80% methane purity and 83% methane recovery. But in the actual operation, disturbances of system state are inevitable and influenced the technical indexes such as purity. The studies of disturbance and control are performed and the controller is designed for the VPSA system. The results demonstrate by introducing the controller, the purity of product can be promised under various disturbances.

    Analysis of dynamic effective mass transfer coefficients of rapid pressure swing adsorption process for oxygen production
    DING Zhaoyang, HAN Zhiyang, SHI Wenrong, SHEN Yuanhui, TIAN Caixia, HAN Yangyuan, ZHANG Donghui
    2018, 69(2):  759-768.  doi:10.11949/j.issn.0438-1157.20171269
    Abstract ( 443 )   PDF (2026KB) ( 325 )  
    References | Related Articles | Metrics

    The mass transfer process of RPSA (rapid pressure swing adsorption) and the effect of varions mass transfer resistances on mass transfer were investigated. The global dynamic mass transfer coefficient was compared with constant mass transfer coefficient. The results show that the dynamic mass transfer coefficients based on axial, membrane diffusion and pore diffusion estimation are effective. Membrane resistance takes up a large part of lumped resistance. Followed by axial diffusion resistance, the macrospores diffusion resistance and the micropores diffusion resistance can be neglected. In the rapid PSA, the mass transfer coefficient will change due to the rapid change of gas velocity and temperature, and the overall trend is that the mass transfer coefficient increases with the increase of temperature and gas velocity. Using the constant mass transfer coefficient cannot accurately describe the mass transfer behavior at each time point and space point in the absorber. The dynamic estimation mass transfer coefficient calculated according to the state of each node can have good coincidence with the behavior in the absorption bed, and the model has high reliability.

    Performance recognition method based on multi-index and multi-layer DAE-SOM algorithm
    LI Mengyao, DU Wenli, QIAN Feng
    2018, 69(2):  769-778.  doi:10.11949/j.issn.0438-1157.20170973
    Abstract ( 292 )   PDF (1894KB) ( 285 )  
    References | Related Articles | Metrics

    As disturbances and other factors often lead to shifting of work point in industrial process, it is particularly important to timely and accurately identify process changes. Current working condition identification methods mainly focus on whether or what fault occurs, but few consider process conditions from viewpoint of safety, economy, fault and other aspects. Decision criteria at different safety and economic conditions were proposed by combination of historical process data and related operational requirements. With these criteria, data characteristics was extracted by DAE method and extracted feature data was clustered by SOM method. Then, the process state was visually projected to two-dimensional maps. In this method, the DAE method can reduce influence of industrial process disturbance on data and the SOM method can better visually monitor process performance. Experimental study showed that the DAE-SOM multi-layer mapping method can determine security level, type of failure, and current economic efficiency of the system.

    Stability and dynamic behaviors of gas-phase ethylene polymerization process under condensed mode operation
    FAN Xiaoqiang, HAN Guodong, HUANG Zhengliang, SUN Jingyuan, WANG Jingdai, YANG Yongrong, WU Wenqing, XIE Lei
    2018, 69(2):  779-791.  doi:10.11949/j.issn.0438-1157.20170791
    Abstract ( 349 )   PDF (854KB) ( 206 )  
    References | Related Articles | Metrics

    Due to significant enhancement in heat removal capacity of recirculating gas and space-time yield of fluidized bed reactors, condensed mode operation has become most popular in gas-phase ethylene polymerization. A mathematical model for condensing mode operation of gas phase ethylene polymerization process was established, which included fluidized-bed reactor model, stage heat exchanger model, and control model of reactor temperature, pressure, and component partial pressure of recirculating gas. Process simulation was applied to obtain steady state solution when reactor temperature was controlled by close-loop, and dynamic behavior of the system under small perturbation was used to qualitatively analyze stability of ethylene polymerization when reactor temperature was controlled by open-loop and close-loop. Finally, stepwise response characteristics of ethylene polymerization close-loop system was studied under consideration of 1-hexene partial pressure and catalyst feed rate. Simulation results show that the steady state solutions are stable within the scope of studied conditions when reactor temperature is close-loop controlled, whereas the steady state solutions are divided into stable and unstable zone by bifurcation points when reactor temperature is open-loop controlled. The long and short period oscillations observed in stepwise response of reactor temperature to 1-hexene partial pressure reveal that ethylene polymerization system under condensed mode operation is a complex process with multiple coupling control loops.

    Part-load performance analysis of cogeneration system for engine waste heat recovery
    TIAN Hua, JING Dongzhan, WANG Xuan, LIU Peng, YU Zhigang
    2018, 69(2):  792-800.  doi:10.11949/j.issn.0438-1157.20170903
    Abstract ( 311 )   PDF (910KB) ( 241 )  
    References | Related Articles | Metrics

    Recovering exhaust waste heat of gas fuel engines is an effective way to improve energy utilization rate. A cogeneration system inclusive of a steam Rankine cycle and an absorption refrigeration cycle is proposed to recover exhaust waste heat of a gas fuel engine. An off-design simulation model is established to analyze part-load performance of the cogeneration system in connection with the characteristics of variable engine load. The results show that the equivalent efficiency of cogeneration system is reduced by 2.14% when the engine load drops from 100% to 40%. Moreover, the improvement of system's total efficiency reduces by only 1.64%. Therefore, the cogeneration system shows excellent part-load adaptability. It should be noted that the absorption refrigeration cycle cannot operate normally under 40% engine load due to the crystallization of H2O-LiBr solution, which can provide the reference for the practical operation.

    Conversion of cellulose into 5-hydroxymehylfurfural catalyzed by CrCl3-AlCl3
    MAO Ming, LENG Erwei, GONG Xun, XU Minghou
    2018, 69(2):  801-807.  doi:10.11949/j.issn.0438-1157.20170981
    Abstract ( 309 )   PDF (616KB) ( 398 )  
    References | Related Articles | Metrics

    5-Hydroxymehylfurfural (HMF), as a valuable platform chemical compound, can be obtained by the direct catalytic conversion of cellulose. The composite catalyst of CrCl3 and AlCl3 was used to convert cellulose into HMF in 1-butyl-3-methyl imidazole chloride ([Bmim]Cl) under oil-bath heating. The effect of catalyst dosage, temperature, cellulose amount, atmosphere, polymerization degree and reaction scale were investigated. The highest HMF yield of 59% was obtained at 4 h when 0.5 g cotton was added into[Bmim]Cl with 25%-2.5% dosage of CrCl3-AlCl3 at 120℃ under N2 (dry) atmosphere. The production efficiency was improved while the cost was reduced. Additionally, the mechanism of degradation of cellulose was proposed.

    Experimental and molecular simulation of corrosion of steel in [BMIM]HSO4 ionic liquid
    ZHANG Jinwei, CHENG Hongye, CHEN Lifang, QI Zhiwen
    2018, 69(2):  808-814.  doi:10.11949/j.issn.0438-1157.20170232
    Abstract ( 411 )   PDF (4590KB) ( 374 )  
    References | Related Articles | Metrics

    The corrosion behaviors of steel in[BMIM]HSO4 ionic liquid (IL) were investigated by immersion tests and molecular simulation. The corrosion rates of stainless steel 304 in IL were determined by mass loss measurement. The result indicates that the presence of H2O greatly enhances the corrosivity of IL. The distribution of HOMO and LUMO, Fukui indices and quantum chemical parameters on IL molecule were calculated. The results show that the imidazolium ring and hydrogen sulfate play the most important role in the interaction between IL and metal surface. The quantum chemical parameters of IL in aqueous solution significantly change. The chemical adsorption ability of IL becomes weak. The adsorption process and adsorption energy of IL on steel surface in water-free and aqueous environments were investigated by molecular dynamics simulation. The molecular simulation results are consistent well with corrosion results, which can provide a better understanding of the interaction between ionic liquid and metal surface at the molecular level.

    Drop-interface electrocoalescence under pulsatile electric fields
    LI Bin, REN Ruijuan, SUN Zhiqian, WANG Zhenbo, LI Xiaoyu, JIN Youhai
    2018, 69(2):  815-822.  doi:10.11949/j.issn.0438-1157.20171068
    Abstract ( 341 )   PDF (1185KB) ( 386 )  
    References | Related Articles | Metrics

    In order to investigate the drop-interface coalescence mechanism under pulsatile electric fields, micro-experiments were conducted on the effect of electrical parameters (electric field intensities, frequencies and waveforms) and physical parameters (surface tension, conductivity, primary droplet size and SiO2 particles) with deionized water as dispersed phase and sunflower oil as continuous phase. The results show that two mechanisms exist, i.e. complete coalescence and partial coalescence, during drop-interface coalescence. The dominant factor is the competition of pumping and necking process. Partial coalescence is enhanced with increasing field strengths, while it is decreased with increasing frequencies. This is resulted from the strength of electrostatic force and the stability of droplets under pulsatile fields. With increasing surfactant concentrations, secondary droplets increase rapidly. When the concentration is higher than that of the critical micelle, secondary droplets decrease slightly. With increasing conductivities and SiO2 concentrations, partial coalescence is enhanced first and then decreases. On the other hand, with increasing primary droplet sizes, partial coalescence increases continuously. Among the waveforms utilized in the experiments, constant DC wave has the highest partial coalescence while sawtooth wave has the lowest. The outcome of this work is potentially useful for optimizing the design of compact and efficient oil-water separators.

    Synthesis and structure of amphiphilic poly(vinylidene fluoride)-b-poly(N-vinylpyrrolidone) block copolymers
    HUANG Zhihui, LIU Jinchao, BAO Yongzhong
    2018, 69(2):  823-829.  doi:10.11949/j.issn.0438-1157.20171037
    Abstract ( 403 )   PDF (10883KB) ( 286 )  
    References | Related Articles | Metrics

    Iodine terminated poly(vinylidene fluoride) was prepared by iodine transfer emulsion polymerization using C6F13I as a chain transfer agent, and further employed to mediate the iodine transfer solution polymerizaton of N-vinylpyrrolidone to prepare amphiphilic poly(vinylidene fluoride)-b-poly(N-vinylpyrrolidone) (PVDF-b-PVP) block copolymers. The molecular and phase structures of PVDF-b-PVP copolymers were characterized by NMR, IR, XRD, DSC and AFM. It is confirmed that PVP block can be effectively inserted between PVDF block and terminated iodine. The order of PVDF chains in the block copolymers was decreased after the incorporation of PVP, resulting the formation of more γ phase PVDF crystals, and the decrease of crystallization temperature and crystallinity degree of PVDF. PVDF-b-PVP copolymers were microphase-separated with a domain size of about 20 nm, and exhibited better hydrophilicity than PVDF homopolymer.

    Surface modification of reverse osmosis membrane by electrostatic deposition of polyelectrolyte for performance improvement
    LIU Meiling, LIU Jun, WANG Qin, TAN Yong, LI Bao'an
    2018, 69(2):  830-839.  doi:10.11949/j.issn.0438-1157.20171021
    Abstract ( 378 )   PDF (3507KB) ( 389 )  
    References | Related Articles | Metrics

    The commercial reverse osmosis (RO) membrane surface was chlorinated with the sodium hypochlorite solution. Then the chitosan as a polycation electrolyte was deposited on the chlorinated RO membrane surface with the help of electrostatic adsorption. With the aim of preparing high flux and high salt rejection RO membrane, the effects of solution pH, chlorination time, sodium hypochlorite concentration, chitosan concentration and deposition time on membrane performance were systematically studied. The water flux and the salt rejection were measured at 1.55 MPa and (298±1) K for a feed NaCl concentration of 2000 μg·g-1. The results showed that, compared to the original RO membrane, the water flux of the chlorinated membrane increased by 19.89% when the chlorination solution pH=9, the chlorination time was 30 min and the chlorination concentration was 1000 mg·L-1. A slightly increase of the salt rejection was also observed. Further modification of chitosan deposition on the chlorinated membrane surface showed that the membrane surface hydrophilicity was enhanced. When the chitosan concentration was 0.1%(mass) and the deposition time was 30 min, the water contact angle of the membrane surface was 34.88° and the salt rejection improved to 99.56%. The water flux of the deposition modified membrane reached 60.55 L·m-2·h-1, which was nearly maintained the same as the chlorinated RO membrane above. These results indicated that both the water flux and the salt rejection of the modified commercial RO membrane improved after the surface modification through chlorination and chitosan deposition.

    Preparation of poly(styrene-b-butyl acrylate-b-styrene) copolymers by single electron transfer-degenerative chain transfer living free radical miniemulsion polymerization
    XU Jinchao, BAO Yongzhong
    2018, 69(2):  840-847.  doi:10.11949/j.issn.0438-1157.20171005
    Abstract ( 304 )   PDF (1348KB) ( 199 )  
    References | Related Articles | Metrics

    Iodine-terminated poly(butyl acrylate) (I-PBA-I) was prepared by single electron transfer-degenerative chain transfer (SET-DT) living free radical miniemulsion polymerization initiated by iodoform, catalyzed by sodium hydrosulfite/sodium bicarbonate and emulsified by dodecyl sodium sulfate/hexadecane. I-PBA-I was further employed as a macromolecular initiator to initiate styrene SET-DT seeded miniemulsion polymerization to prepare polystyrene-b-poly(butyl acrylate)-b-polystyrene (PS-b-PBA-b-PS) block copolymers. The structure and properties of PS-b-PBA-b-PS copolymers were characterized. Both butyl acrylate and styrene miniemulsion polymerizations exhibit great polymerization rates, and the dosage of initiator can be decreased, which is favor to preparing PBA and PS-b-PBA-b-PS copolymer with high molecular weights. PS-b-PBA-b-PS copolymers exhibit characteristics of micro-phase separation and thermoplastic elastomer. For PS-b-PBA-b-PS copolymer with PS mass fraction of 50%, the ultimate tensile strength and the elongation at break can reach 9.8 MPa and 660%, respectively.

    Characteristics of boron adsorption onto a novel chitosan/zirconium composite particles
    WANG Xiong, LIU Mingyan
    2018, 69(2):  848-857.  doi:10.11949/j.issn.0438-1157.20170634
    Abstract ( 327 )   PDF (2831KB) ( 279 )  
    References | Related Articles | Metrics

    A new type of chitosan-zirconium composite particles (CTS-Zr) has been prepared through coordination reaction between zirconium oxychloride and chitosan, and in-situ precipitation of zirconium hydroxide for the adsorption of boron from solution. The CTS-Zr composite was characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The effects of pH, initial boron concentration, contact time, temperature and co-existing ions Cl-, NO3-, and SO42- on adsorption performance were also investigated systematically. The results demonstrated that prepared adsorbent could maintain high boron adsorption efficiency in a pH range from 2 to 7. The equilibrium adsorption behavior of boron on the CTS-Zr composite had a good agreement with the Langmuir isotherm model, and the maximum adsorption capacity was calculated as 21.1 mg·g-1 with pH of 7. The uptake kinetics was fitted well with the pseudo-second order rate equation, and the common coexisting anions almost had no negative effect on the boron adsorption. The results of adsorption thermodynamics of boron on CTS-Zr indicate the exothermic and not spontaneous nature of the adsorption process. The boron adsorbed on CTS-Zr particles was regenerated with an efficiency of 96.3% using NaOH solution of pH of 12, and the adsorption efficiency was not significantly reduced after three adsorption-desorption cycles.

    Biguanidine functionalized polyvinylamine modified reverse osmosis membrane with improved anti-bacterial property
    ZHOU Yixuan, WANG Zhi, DONG Chenxi, WANG Yao, WANG Jixiao
    2018, 69(2):  858-865.  doi:10.11949/j.issn.0438-1157.20170978
    Abstract ( 327 )   PDF (10076KB) ( 306 )  
    References | Related Articles | Metrics

    Membrane bio-fouling is one of the main obstacles for the wide application of reverse osmosis (RO) membrane technology. To solve this problem, a novel anti-bacterial RO membrane was fabricated by second interfacial polymerization of self-synthesized cationic biguanidine functionalized polyvinylamine (PVAmG). Virgin membranes and the polyvinylamine (PVAm)-modified RO membranes were prepared for comparisons. The chemical structures of PVAm and PVAmG were characterized by Fourier transform infrared spectroscopy and elemental analysis. The membranes were systematically characterized by XPS, SEM, AFM, contact angle analyzer and Zeta potential analyzer. The test results show that the modified membranes well maintain the high permselectivity. Moreover, the PVAmG-modified membranes exhibited strong anti-bacterial property (mortalities of 99.9%) against both the Gram-negative Escherichia coli and Gram-positive Bacillus subtilis.

    Desulfurization performance of activated carbon filled PEG/PVDF hybrid membrane
    ZHANG Xingmei, HU Wenling, SUN Hexiang, HAN Xiaolong, WANG Yuqi
    2018, 69(2):  866-872.  doi:10.11949/j.issn.0438-1157.20171101
    Abstract ( 317 )   PDF (1992KB) ( 182 )  
    References | Related Articles | Metrics

    Activated carbon filled PEG/VPDF membranes with different activated carbon (AC) loading were prepared. The morphology and structure of the prepared AC-PEG/PVDF hybrid membranes were characterized. The thiophene/n-heptane mixture was used as a simulated gasoline system, the desulfurization of membranes were studied systematically. The results showed that the desulfurization of the AC-PEG/PVDF hybrid membranes were improved. When the content of activated carbon is 5% and the temperature is 85℃, the permeation flux and sulfur enrichment factor of the membrane were improved from 0.43 kg·(m2·h)-1 and 7.29 to 1.14 kg·(m2·h)-1 and 9.47, respectively.

    Characteristics and trends of chemical engineering research based on bibliometric analysis of typical periodicals -Analysis on Journals of CIESC Journal, AIChE Journal, Chemical Engineering Science and Industrial & Engineering Chemistry Research
    WU Man, SONG Aifang, ZHANG Yan, GUO Qingjie
    2018, 69(2):  873-884.  doi:10.11949/j.issn.0438-1157.20171149
    Abstract ( 658 )   PDF (544KB) ( 532 )  
    References | Related Articles | Metrics

    Using bibliometrical analysis method, this study analyzed the paper productivity, research institutions, index term, cited literature and citation literature of 49565 journal papers published in the journals of CIESC Journal, AIChE Journal, Chemical Engineering Science (CES) and Industrial & Engineering Chemistry Research (IECR) during the last 20 years (1996-2015) from Scifinder Web database. It will provide a valuable reference for the construction of “Double World-class” and the development of academic periodicals in chemical engineering fields. The paper productivity and the ranking of Chinese research institutions were increased, which indicated the strong development momentum and international influence of Chinese chemical research in recent years. At the same time, the academic research of chemical engineering in domestic institutions has become increasingly active. In the past, the high-level academic papers were only published by a few leading scientific research institutions. However, the phenomenon was changed over time. In addition, the research focus and hotspot between the CIESC Journal and the three mainstream journals AIChE Journal, CES and IECR were similar. During recent 10 years (2006-2015), in the research fields of “polymer morphology”, “ionic liquids” and “nanoparticles”, the Chinese institutions had larger contribution to the three major international periodicals of chemical engineering.