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Table of Content
05 June 2017, Volume 68 Issue 6
    Research progress on co-contamination and remediation of heavy metals and polycyclic aromatic hydrocarbons in soil and groundwater
    YANG Yuesuo, CHEN Yu, LI Panpan, WU Yuhui, ZHAO Chuanqi
    2017, 68(6):  2219-2232.  doi:10.11949/j.issn.0438-1157.20161805
    Abstract ( 655 )   PDF (4179KB) ( 802 )  
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    The understanding of environmental contamination is gradually improved as better investigation and research are achieved. Previous study on single contaminants was no longer adequate in coping with the increasing occurrences of complex environmental co-contaminations, which have been addressed more and more. Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the environment, whose co-contaminations are frequently detected in the environment and their interactions have often made the remediation problematic. Soil and groundwater, the major bio-habitats, are the venues where such co-contaminations of HMs and PAHs occur. The co-contaminations of soil and groundwater will seriously threaten human and other ecological health. This paper hence reviews the source, distribution, migration, transformation and eco-toxicity of the co-contaminations of HMs and PAHs. It also briefly summarizes the interactions between contaminants and potential remediation technologies of the co-contaminations. The perspective research directions of such co-contaminations are proposed based upon the literature review.

    Progress of solid-liquid suspension in stirred vessel
    YANG Fengling, ZHOU Shenjie
    2017, 68(6):  2233-2248.  doi:10.11949/j.issn.0438-1157.20161619
    Abstract ( 436 )   PDF (514KB) ( 1213 )  
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    Solid-liquid suspension is one of the typical unit operations in the process industry and accordingly, study on the suspension performance is of great importance. In this paper, developments of investigations on the solid-liquid suspension in stirred vessels in the past six decades were reviewed. Subsequently, configurations of the commonly used stirred systems were introduced. The critical suspension speeds of solid particles in baffled and unbaffled stirred vessels were clarified and compared. Finally, the principles of different experimental and numerical methods related with solid-liquid suspensions were presented. Investigations on the effect of free surface deformation on solids suspension and the research status were briefly summarized. The future development of numerical simulation on the solid-liquid suspension in stirred vessels is discussed.

    Progress in preparation of MnOx and its application
    ZHANG Xiaodong, LI Hongxin, HOU Fulin, YANG Yang, DONG Han, CUI Lifeng
    2017, 68(6):  2249-2257.  doi:10.11949/j.issn.0438-1157.20161329
    Abstract ( 450 )   PDF (629KB) ( 856 )  
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    It is know that Mn is a common variable valene metal, which plays a good catalytic role in catalytic reaction. Due to the large specific surface area, strong adsorption performance and the excellent catalytic activity, a common transition metal oxide MnOx has become a hot topic in the field of environmental pollution control and energy. In this paper, recent progress in the synthesis method of MnOx and its application, such as CO catalytic oxidation, volatile organic pollutants catalytic oxidation, gas adsorption and separation and battery electrode materials, has been summarized.

    Thermodynamic analysis of catalytic hydrogenation of methyl oleate to produce bio-paraffins
    SUN Peiyong, LI Mengchen, LIU Sen, QI Qi, ZHANG Shenghong, YAO Zhilong
    2017, 68(6):  2258-2265.  doi:10.11949/j.issn.0438-1157.20161808
    Abstract ( 460 )   PDF (558KB) ( 450 )  
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    The thermodynamic analysis of the hydrogenation of methyl oleate to bio-paraffins via hydrodeoxygenation (HDO), hydrodecarbonylation (HDCO) or hydrodecarboxylation (HDCO2) routes was carried out by the Benson group-contribution method. Changes of enthalpy, entropy and Gibbs free energy, as well as the standard equilibrium constants, for each reaction were calculated in the temperature range of 613—653 K. The equilibrium distribution of products as a function of temperature was also simulated based on an equilibrium reactor of PRO/Ⅱ software and compared with the experimental data. The calculated thermodynamics indicates that HDO, HDCO and HDCO2 of methyl oleate are exothermic processes, with the released heat decreasing in the order of HDO>HDCO2>HDCO, and each reaction can take place spontaneously and proceed completely. Moreover, improving temperature prefers HDC to HDO products at equilibrium, results in a decreasing HDO/HDC ratio from 1.92 to 0.56 as the temperature rises from 613 K to 653 K, consisting well with the experimental data collected in the catalytic hydrogenation of methyl oleate.

    Visualization study on flow pattern of gas-liquid two-phase flowing through multi-orifice plate in horizontal pipe
    PENG Jiewei, MA Youfu, WU Hengliang, LÜ Junfu, LIU Yuan, PENG An, JIAO Qianfeng
    2017, 68(6):  2266-2274.  doi:10.11949/j.issn.0438-1157.20161726
    Abstract ( 491 )   PDF (11330KB) ( 427 )  
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    Producing a bubble flow in multi-orifice plate downstream (MOPD) is a basic condition for the exhaust absorber with multi-orifice plates to achieve a satisfied absorption capacity. In this paper, a visualization experiment on the flow pattern of gas-liquid two-phase flowing through a multi-orifice plate in a horizontal pipe was conducted using the air and water as the gas and liquid phase, respectively. Four multi-orifice plates with the orifice diameter of 2, 3, 4 and 5 mm were tested in a horizontal plexiglass pipe with the inner diameter of 98.5 mm by using a high speed camcorder to record the air-water flow, thus the effects of orifice diameter, air flow rate and water flow rate on the flow pattern in the multi-orifice plate downstream were obtained. The results show that the stratified/plug flow transition in MOPD shift to an increased water flow rate while the plug/bubble flow transition shift to a decreased water flow rate in comparison with the flow pattern transition in horizontal pipes. The flow pattern in MOPD is inclined to a bubble flow with the decrease of air flow rate or the increase of water flow rate. Meanwhile, an important dependence on the orifice diameter is found for the flow pattern in MOPD. With the decrease of orifice diameter, the plug/bubble flow transition shift to an increased air flow rate and a decreased water flow rate, meaning that an increased flow range is obtained to form bubble flow. In addition, as the orifice diameter decreasing, the flow pattern in MOPD is inclined to transfer from wavy stratified flow to bubble flow directly without an occurrence of plug flow. To achieve a satisfied flow pattern and absorption capacity for the exhaust absorber with multi-orifice plates, it is recommended to choose the orifice diameter not larger than 3 mm.

    Single-phase heat transfer characteristics of R32 flowing through metallic foam filled channel
    PAK Yongil, WU Xiaomin, MA Qiang, LI Tong
    2017, 68(6):  2275-2279.  doi:10.11949/j.issn.0438-1157.20161218
    Abstract ( 334 )   PDF (1228KB) ( 495 )  
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    By electric heating method of metal foam, temperature distribution of R32 and porous fibre were measured and the heat transfer coefficients between them were obtained in metallic foam filled channels. The experiments were conducted for R32 in a metallic foam filled tube with an internal diameter of 5 mm, the 0.95 porosity and 15, 45 PPI pore densities, under the conditions of fluid temperature of 280—325 K, heat flux ranging of 1—18 kW·m-2, and mass flux ranging of 20—200 kg·m-2·s-1. Following conclusions could be summarized from the results of the experiments. The heat transfer coefficients of R32 flowing through porous fibres increased with the increase of Re and pore densities. The deviation between predicted values of heat transfer coefficient based on conventional correlation and experimental data reached to-35%—-67%, that is, the conventional correlation is not suitable to predict the convective heat transfer between the porous fibre and the fluid.

    CFD simulation on shear-thinning gas-liquid dispersion in coaxial mixer
    LIU Baoqing, ZHENG Yijun, LIANG Huili, WANG Manman, JIN Zhijiang
    2017, 68(6):  2280-2289.  doi:10.11949/j.issn.0438-1157.20161749
    Abstract ( 335 )   PDF (16042KB) ( 350 )  
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    Gas-liquid mixing equipment has broad industrial applications for its good performance in gas dispersion with increased contact area between gas and liquid phases. In order to understand gas-liquid dispersion in industrial process of shear-thinning liquid system under different working conditions, appropriate rotation mode was first determined experimentally by studying overall gas holdup and relative power demand and effect of apparent gas velocity, system viscosity, and stirring speed on gas holdup and bubble size was then investigated by population balance and multiple size group model simulation. Results showed that, coaxial mixer in contra-rotation mode had larger overall gas holdup and better gas pumping capacity than mixer with single inner impeller or coaxial mixer in co-rotation mode at conditions of ideal gas-liquid dispersion and same power consumption. Increasing apparent gas velocity forced more homogeneous gas holdup and larger bubble size. Increasing system viscosity reduced impeller affecting zone and homogeneity of gas holdup but increased bubble size. Increasing stirring speed enlarged affecting area of circular vortex and extended high gas holdup area.

    Prediction of agglomerate size for ultrafine particles in acoustic spouted fluidized-bed with draft tube
    GAO Kaige, LEI Yuzhuang, LI Hainian, ZHOU Yong
    2017, 68(6):  2290-2297.  doi:10.11949/j.issn.0438-1157.20161792
    Abstract ( 305 )   PDF (2425KB) ( 314 )  
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    The fluidization property of ultrafine particles is closely related to their agglomerate size. Through the analysis of the formation process of ultrafine powder agglomerates in an acoustic spouted fluidized-bed with a draft tube, it is proposed that the shearing action of high speed jet and collision between agglomerates were the dominating factors to influence agglomerate size. Based on the force balance analysis acting on the agglomerates during the jet shearing process and collision between agglomerates, a model to predict agglomerate size distribution in an acoustic spouted fluidized-bed with a draft tube was established. The average size of agglomerates and their size distribution of TiO2 ultrafine powder at different jet velocities in the bed were predicted by the model successfully.

    Under-expanded jets and dispersion during big hole leakage of high pressure CO2 pipeline in industrial scale
    YU Jianliang, ZHENG Yangguang, YAN Xingqing, GUO Xiaolu, CAO Qi, ZHU Hailong, LIU Shaorong
    2017, 68(6):  2298-2305.  doi:10.11949/j.issn.0438-1157.20161614
    Abstract ( 399 )   PDF (9731KB) ( 372 )  
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    Based on two groups of gaseous and supercritical CO2 release experiments using an industrial scale CO2 pipeline (258 m long, 233 mm i.d.) through a 100 mm diameter orifice, the dynamic pressure and visible cloud in the near field, and the temperature and concentration changes in the diffusion region were analyzed. The results show that the sharp drop in inventory pressure near the orifice produced a highly under-expanded jet and induced a sharp drop in temperature as a result of Joule-Thomson cooling. This effect led to the formation of solid CO2 particles inside the under-expanded jet. The visible cloud remained a metastable state after the rapid expansion, and followed by a slow attenuation stage. The visible white cloud entraining the dry ice particles and condensed water rapidly expanded in the rapid expansion stage and dry ice particles have been sublimated into the ground before and did not form the ice bed. At the moment of the rupture, the temperature in the discharge area of gaseous and supercritical CO2 releases dropped rapidly and then increased slowly, while the CO2 concentrations increased quickly and then decreased. The dangerous distance of the 5% concentration of gaseous and supercritical CO2 releases were at least 30 m and 50 m respectively.

    Heat transfer of oil-gas slug flow in horizontal pipe
    WANG Xin, WANG Zhaoting, ZHANG Xiaoling, HE Limin
    2017, 68(6):  2306-2314.  doi:10.11949/j.issn.0438-1157.20161556
    Abstract ( 265 )   PDF (732KB) ( 409 )  
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    The heat transfer in the cooling process of subsea oil and gas pipeline is a key factor of the flow assurance in offshore petroleum industry, such as wax, hydrate etc. In this study, capacitance probe, thermocouple and resistance thermometer were used to measure the flow and heat transfer characteristics of oil-gas slug flow in different cooling conditions and the effect of flow parameters on heat transfer of slug flow was analyzed. It was demonstrated that the convective heat transfer coefficient of oil-gas slug flow is mainly affected by the liquid superficial velocity. While the temperature of the outer cooling fluid is decreased, the viscosity of the inner thermal fluid at the bottom of the tube will increase and the thickness of the thermal boundary layer will be increased, therefore the heat transfer will be deteriorated. Also the convective heat transfer coefficient of oil-gas is much lower than that of water-gas due to the different viscous force and boundary layer. The local convective heat transfer coefficient is increasing from the top to the bottom of the tube along the circumferential direction. Moreover, the correlation and heat transfer model of oil-gas slug flow under cooling condition were presented.

    Thermal conduction mechanism of multi-walled carbon nanotubes-deionized water nanofluids and experimental research in gravity heat pipe
    WU Han, YANG Jun
    2017, 68(6):  2315-2320.  doi:10.11949/j.issn.0438-1157.20161492
    Abstract ( 316 )   PDF (490KB) ( 379 )  
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    An improved model of thermal conduction of multi-walled carbon nanotubes-deionized water (MWCNTs-DW) nanofluids is proposed based on the Xue model by considering interfacial nanolayer, analyzing heat conduction, derivating thermal conductivity of MWCNTs-DW nanofluids and applyingMWCNTs-DW nanofluids to the research of heat transfer in gravity heat pipe. Different mass fraction of nanofluids gravity heat pipe are prepared and investigated using the nanofluid as the work liquid and the carbon steel pipe as material. The result shows that the interface nanolayer increases the effective thermal conductivity and the mass fraction of 2% is best performance under the same conditions, the heat transfer coefficient of nanofluids gravity heat pipe increases by 40% to the max than that of the base fluid water.

    Numerical simulation of stable flow dynamics of viscous film on spinning disk surface
    WANG Dongxiang, LING Xiang, PENG Hao, YANG Xinjun, CUI Zhengwei
    2017, 68(6):  2321-2327.  doi:10.11949/j.issn.0438-1157.20170040
    Abstract ( 302 )   PDF (583KB) ( 359 )  
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    Film flow on spinning disk surface exists extensively in chemical engineering operations, such as centrifugal graining, molecular distillation and spinning disk reactors. Flow dynamics of the film flow has a major impact on graining, reaction, heat and mass transfer rate. Theoretical model of stable film flow dynamics was established and verified by comparison of experimental results and numerical simulations. The effect of equivalent Froude number, dimensionless ratio of characteristic thickness over length ε, and casting size ri on dimensionless film thickness distribution was studied, which a model of dimensionless hydraulic jump and synchronized zone radius was derived and verified by experiments. The results show that equivalent Froude number has little effect on film thickness distribution and occurrence of hydraulic jump phenomenon mainly depends upon ε and ri. Increasing ε or decreasing ri leads to appearance of hydraulic jump with a dimensionless hydraulic jump radius always at r=0.85. Mean radial velocity exhibited features of typical three zone distribution. Reducing casting size would extend injection zone and shrink acceleration zone, such that film flow goes directly to synchronized zone at dimensionless synchronized radius of 1.53 without evident acceleration. The results will provide theoretical reference for design and optimization of spinning disk reactors and centrifugal pelletizers.

    Dynamic characteristics of impeller of perturbed six-bent-bladed turbine in pseudoplastic fluid based on fluid-structure interaction
    LUAN Deyu, ZHANG Shengfeng, ZHENG Shenxiao, WEI Xing, WANG Yue
    2017, 68(6):  2328-2335.  doi:10.11949/j.issn.0438-1157.20161651
    Abstract ( 320 )   PDF (1740KB) ( 589 )  
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    Dynamic characteristics ofimpeller of perturbed six-bent-bladed turbine (6PBT) and six-bent-bladed turbine (6BT) are analyzedcomparatively using bidirectional fluid-structure interaction (FSI) method based on simulation platform ANSYS Workbench. Macroscopic flow field structure and power consumption caused by the coupling action between the blade and fluid are studied, and the total deformation and equivalent stress distribution along the blade are also analyzed. Besides, the natural and prestressed mode of the 6PBT impeller are investigated comparatively. The results show that, compared with 6BT impeller, the tip deformation and stress of 6PBT impeller are increased by 8% and 61%, respectively, while its root stress is reduced by 6.7% with the well stress distribution of the blade along the radial direction, which indicates that the interaction force between 6PBT impeller and fluid is stronger, resulting in the faster energy dissipation, at the meantime, the blade strength is also improved. The vibration mode of 6PBT impeller under prestressed mode is consistent with that of natural mode, and the modal frequency has no significant changes on the prestressed action, which shows that the fluid-structure interaction and prestressed action have little influence on the blade mode. With the increasing speed, 6PBT impeller has an advantage with a better energy saving effect.

    Synthesis process of 4-(6-hydroxyhexyloxy)phenol in microreactor
    LI Lei, ZHOU Feng, YAO Chaoqun, CHEN Guangwen
    2017, 68(6):  2336-2343.  doi:10.11949/j.issn.0438-1157.20170071
    Abstract ( 360 )   PDF (2459KB) ( 361 )  
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    This work mainly studied the process of producing 4-(6-hydroxyhexyloxy) phenol with Williamson synthesis in the microreactor. The Box-Behnken model in response surface methodology was used to design the experiments to investigate the effects of reaction temperature, catalyst concentration, reactant ratio, residence time, as well as the interaction among factors, on the yield. The quadratic model was established to correlate the variables to the response values. According to the model, the optimum operating parameters were determined as following temperature 135℃, the concentration of NaOH 2.35 mol·L-1, reactant ratio 2.81, and residence time 2.70 min. Under the optimum conditions, the yield can reach 79.5%, and the error of the predicted and experimental values can be negligible, which showed the accuracy of the model. In addition, a feasible product purification method was proposed, and the structure of the product was confirmed by the 1H NMR spectra.

    Catalytic performance of CuO/HZSM-5 in aromatic synthesis from CH3Br
    CHEN Tan, CHEN Hao, FU Jie, CHEN Kequan, OUYANG Pingkai
    2017, 68(6):  2344-2351.  doi:10.11949/j.issn.0438-1157.20161659
    Abstract ( 325 )   PDF (3471KB) ( 396 )  
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    CuO/HZSM-5 catalysts with 1%—7% CuO loading, which were prepared by incipient wetness impregnation, were used to study catalytic performance in the conversion of CH3Br to aromatic compounds in a fixed-bed reactor by changing temperature, CH3Br flow rate and CuO loading. Fresh and used catalysts were characterized by SEM, TEM, XRD, XPS, TG, DSC, N2 adsorption and desorption, and NH3-TPD. XRD results showed that CuO was highly dispersed on HZSM-5 and structure of CuO crystals did not change during reaction. NH3-TPD results showed that 3% (mass) CuO loading increased strong acidity of catalyst. XPS results showed that coke deposition on used CuO/HZSM-5 catalyst was mainly graphite. The highest aromatic yield of 22.3% was achieved at condition of 3% (mass) CuO loading, 360℃ temperature and 240 ml·g-1·h-1 GHSV. The 3% (mass) CuO/HZSM-5 maintained stable catalytic activity within 40 h reaction time.

    Selective hydrogenation of maleic anhydride over Ni/ZrO2 catalysts with ZrO2 prepared by methanol thermal method
    LIANG Eryan, ZHANG Yin, ZHAO Lili, XU Yalin, ZHAO Yongxiang
    2017, 68(6):  2352-2358.  doi:10.11949/j.issn.0438-1157.20170005
    Abstract ( 270 )   PDF (590KB) ( 247 )  
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    A series of tetragonal ZrO2 which support different crystalline size were prepared by methanol thermal method. Ni/ZrO2 catalysts with Ni content of 10%(mass) were prepared by impregnation method and applied in the liquid phase hydrogenation of maleic anhydride. All catalysts were characterized by N2 physical adsorption-desorption, H2-temperature programmed reduction(H2-TPR), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and in situ Fourier transform infrared spectroscopy(in situ FTIR). Higher dispersion and smaller crystallite size of metallic Ni favored the hydrogenation of C=C to produce succinic anhydride. While the formation of strong metal-support interaction contributed the hydrogenation of C=O to produce γ-butyrolactone. When methanol thermal time was 2 h, the Ni/ZrO2-2 catalyst showed the highest catalytic activity for C=O hydrogenation.

    Selective hydrogenolysis of sorbitol on Ni/La2O2CO3 catalysts
    ZHANG Tao, LIU Qiying, ZHANG Caihong, ZHANG Qi, MA Longlong
    2017, 68(6):  2359-2367.  doi:10.11949/j.issn.0438-1157.20170043
    Abstract ( 337 )   PDF (4363KB) ( 318 )  
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    Ni/La2O2CO3 catalysts with different Ni/La ratios were prepared by co-precipitation and the performance was tested in selective hydrogenolysis of sorbitol to C2—C3 polyols. The catalysts were characterized by X-ray diffraction(XRD), H2 temperature-programmed reduction(H2-TPR), CO2 temperature-programmed desorption(CO2-TPD) and scanning electron microscopy(SEM). The effect of hydrogenation and base regulation was investigated by varying the Ni/La ratios. The result shows that the conversion of sorbitol was 98.6% and the yields of C2—C3 polyols was 43.8% when the mole ratio of Ni to La is 2:3. After two times of reaction, the catalyst still achieved a sorbitol conversion of 90%. From acidic to alkaline, the products distribution of hydrogenolysis of sorbitol was discussed. The reaction pathway was also proposed based on the experiment results.

    Production of butyl levulinate from bio-furfuryl alcohol catalyzed by ferric sulfate
    CHANG Chun, BAI Jing, AN Ran, DENG Lin, QI Xiaoge, XU Yanli
    2017, 68(6):  2368-2375.  doi:10.11949/j.issn.0438-1157.20170047
    Abstract ( 352 )   PDF (812KB) ( 327 )  
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    Butyl levulinate is an important bio-based chemicals with diverse industrial applications. A single step conversion of bio-based furfuryl alcohol to butyl levulinate was investigated with ferric sulfate as catalyst. Process optimization of furfural alcohol conversion was conducted by response surface methodology with 86.7% average yield of butyl levulinate obtained under optimum conditions. Adding toluene further improved butyl levulinate yield to 90.7%. Reusability study showed that ferric sulfate was easily recycled and could maintain high catalytic activity after used more than three times. Structures of fresh and recycled catalysts were characterized by FT-IR and XRD. Composition analysis of liquid products and calculation of process mass balance elucidated possible reaction pathway for butyl levulinate production form furfuryl alcohol.

    Optimization of Ni-P/APO-11 amorphous catalyst for catalytic hydrogenation of turpentine using response surface methodology
    PAN Deng, WANG Yaming, ZHONG Shenjie, JIANG Lihong
    2017, 68(6):  2376-2385.  doi:10.11949/j.issn.0438-1157.20161534
    Abstract ( 254 )   PDF (15914KB) ( 150 )  
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    APO-11 aluminophosphate molecular sieve was prepared from diisopropylamine and calmogastrin by hydrothermal synthesis method. The amorphous catalysts Ni-P/APO-11were prepared by chemical reduction and applied in the catalytic hydrogenation of turpentine. The α-pinene hydrogenation reactions were investigated and optimized by response surface methodology, meanwhile, amorphous catalysts were characterized by XRD, BET, SEM, XPS, and ICP. Under reaction temperature 124.8℃, reaction pressure 4.9 MPa, catalyst amount 6.3%, and reaction time 90 minutes, the conversion rate of α-pinene was 99.45%, the selectivity of cis-pinane was 97.35%. Meanwhile, the catalysts were used in catalytic hydrogenation of other components to broaden the range of catalysts and improve deep process of turpentine, the catalysts exhibited high catalytic activity, raw conversion was reached more than 99%, and the selectivity was reached more than 65%.

    Preparation of bamboo carbon-based solid acid and its catalytic properties
    MA Bingbing, LIU Xiben, LI Chuanliang, WEI Yi, JI Weirong
    2017, 68(6):  2386-2393.  doi:10.11949/j.issn.0438-1157.20161850
    Abstract ( 360 )   PDF (1575KB) ( 479 )  
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    Bamboo carbon-based solid acid was prepared via sulfuric acid impregnation, carbonization and sulfonation with cellulose-rich bamboo powder as feedstock, and its application in cellulose hydrolysis was studied. Firstly, the results obtained by TG of raw and modified bamboo powders and their main components showed that sulfuric acid had significant effects on breaking the chemical bonds in bamboo power to promote the pyrolysis and carbonization processes at lower temperature. The systematically research was conducted on the impregnation ratio, impregnation concentration, carbonization temperature and sulfonation temperature, which strongly affected the catalytic properties of bamboo carbon-based solid acid. Then, the optimal preparation conditions were obtained. Finally, the bamboo carbon-based solid acid was characterized by XRD, BET, FT-IR and SEM. These results indicated that the bamboo carbon-based solid catalyst had a favourable textile structure and considerable sulfonic acid content, showing that the sulfonic acid content was related to the number of active hydrogen on the aromatic carbon.

    Reaction of diaryl disulfides with nitroarenes
    LI Shuyan, SUN Lina, SHEN Shujun, CHENG Tianxing, CHENG Shuanghua, CHEN Jiuxi
    2017, 68(6):  2394-2398.  doi:10.11949/j.issn.0438-1157.20161755
    Abstract ( 411 )   PDF (425KB) ( 468 )  
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    The cheap and readily available Rongalite®/K2CO3 promoted the reaction of diaryl disulfides with nitroarenes in DMSO at 50 ℃, providing a convenient route to the synthesis of unsymmetrica diaryl sulfide. The structures of all products were characterized by 1H NMR and 13C NMR. This protocol had some distinct advantages of mild conditions, readily available starting materials and simple work-up.

    High-throughput screening methods for protein adsorption evaluation with microtiter filter plate
    CHU Wenning, LIN Dongqiang, YAO Shanjing
    2017, 68(6):  2399-2406.  doi:10.11949/j.issn.0438-1157.20161789
    Abstract ( 366 )   PDF (2448KB) ( 564 )  
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    Aiming at the process optimization of chromatographic separation, the high-throughput screening methods of protein adsorption with microtiter filter plate were established for initial resin screening, adsorption properties evaluation, adsorption isotherms and adsorption kinetics measurement, and adsorption and elution conditions optimization. Firstly, the operation parameters of 96-well filter plate were optimized, and with two ion exchangers and two mixed-mode resins as the model, the bovine serum albumin adsorption was investigated with different resins and liquid conditions by means of microtiter filer plate. The binding capacity maps were obtained and the appropriate adsorption-desorption conditions were determined. Further, the microtiter filter plate was applied to measure the adsorption isotherms and adsorption kinetics with four resins at specific adsorption conditions, and the adsorption parameters were obtained. Finally, the elution conditions were optimized using microtiter filter plate. The microscale results were comparable to that with packed-bed separation, indicating that the methods developed in the present work were practicable. The results demonstrated that the high-throughput process development of protein adsorption with microtiter filer plate was feasible and can be used to fast screen the best reins and liquid conditions. New methods showed the advantages of low resource consumption, large experimental fluxes, short developing period, wide application and high stability, which would be one new method for development of the protein separation process.

    Separation of n-butyl acetate from aqueous solution using PDMS membrane filled with hydrophobic SiO2
    MU Chunxia, ZHANG Shiyu, ZOU Yun, LIU Xiangjun, DONG Yanbo, CUI Xuemin, TONG Zhangfa
    2017, 68(6):  2407-2414.  doi:10.11949/j.issn.0438-1157.20161508
    Abstract ( 336 )   PDF (3802KB) ( 598 )  
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    The modified polydimethysiloxane (PDMS) hybrid membranes with hydrophobic nano SiO2 as filler and using PVDF film as support layer were prepared for pervaporation of n-butyl acetate from aqueous solution. The physciochemical properties of membranes were characterized by SEM, FTIR, XRD, tensile testing, contact angle and positron annihilation lifetime spectroscopy(PALS). The effects of the loading of SiO2, feed concentration, feed temperature on swelling behavior and pervaporation performance were studied. The results indicated that SiO2 particles dispersed uniformly in the membrane material and no chemical change occurred between SiO2 and PDMS polymer chain. The mechanical strength and hydrophobic properties of the filled film were obviously improved by incorporation of SiO2. With the increase of SiO2 content, the adsorption capacity of n-butyl acetate increased and then decreased, while the permeation flux decreased and the separation factor increased initially and then decreased. When SiO2 content was 4%(mass), the permeation flux increased while the separation factor increased initially and then decreased with the rise of the feed concentration. The permeation flux increased with increase of the feed temperature, however, the separation factor decreased. The maximum values of the permeation flux and the separation factor were 240 g·m-2·h-1 and 542 respectively.

    Absorption of SO2 by single hydrophobic ceramic tubule-based membrane contactor
    HAN Shixian, GAO Xingyin, FU Kaiyun, QIU Minghui, FAN Yiqun
    2017, 68(6):  2415-2422.  doi:10.11949/j.issn.0438-1157.20170012
    Abstract ( 318 )   PDF (2027KB) ( 399 )  
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    The emission of SOx from marine vessels has caused serious environmental problem. Membrane contactor that offers several advantages over conventional tower device such as a compact size, operational flexibility, independent gas and liquid flow, easy scale-up, and modularity is an alternative technology in the application of marine exhaust gas desulfurization. In this work, a single ceramic tubule-based membrane contactor was fabricated from ZrO2 ceramic membrane with average pore size of 200 nm. A series of experiments of SO2 absorption were carried out using water as low-cost absorbent. The mass transfer performance of the unmodified and modified membrane was compared and the effects of gas flow rate, absorbent flow rate, feed gas concentration, temperature of absorbent on SO2 removal efficiency and mass transfer rate were investigated. The long-term stability of ceramic membrane contactor was tested as well. It was found that the overall structures and the surface porosity of ceramic membrane hardly changed by surface modification with hexadecyltrimethoxysilane (HDTMS). The hydrophobic ceramic membrane with contact angle of 132° had higher desulfurization efficiency and overall mass transfer coefficient than those of the unmodified membrane under the same operating conditions. The desulfurization efficiency and mass transfer rate increased as the liquid flow rate increased. The desulfurization efficiency decreased as the gas flow rate and feed gas concentration increased while the mass transfer rate increased. Absorbent with low temperature was more favorable for the absorption of SO2. CO2 in the feed gas had little effect on the SO2 removal efficiency. The ceramic membrane contactor had lower height of transfer unit(HTU)value than conventional packed tower and showed great potential in the application of exhaust gas desulfurization.

    Effects of temporary shutdown time-threshold on oxygen production schedule in air separation unit
    ZHANG Peikun, WANG Li
    2017, 68(6):  2423-2433.  doi:10.11949/j.issn.0438-1157.20161690
    Abstract ( 287 )   PDF (1761KB) ( 310 )  
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    Aimed at oxygen scheduling challenge under the scenario of blast furnace blow-down in integrated iron steel enterprises, a control strategy based on short-term shutdown of air separation units (ASUs) was proposed with an establishment of optimal scheduling model for oxygen distribution system by the mixed integer linear program. The objective of model optimization was to minimize overall oxygen pressure across high pressure oxygen piping network during entire scheduled cycle. The model included constraints for temporary shutdown and restart of ASUs and some oxygen compressors, as well as stop and run time thresholds of these equipment in real situations. A case study of a mega integrated iron and steel enterprise in China was performed to examine rationality and feasibility of the proposed model and to analyze effects of shutdown time threshold of ASUs on scheduling target by the model. The results show that a shorter shutdown time-threshold of ASU is generally propitious to achieve more optimal objective, which relationship between time-threshold and scheduling objective has non-linear leaping characteristic.

    SA-ELM based method for reconstructing temperature distribution in acoustic tomography measurement
    LIU Sha, LIU Shi, REN Ting
    2017, 68(6):  2434-2446.  doi:10.11949/j.issn.0438-1157.20161597
    Abstract ( 267 )   PDF (13561KB) ( 267 )  
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    Obtaining accurate information of temperature distribution plays an important role in chemical industry. As a result of advantages such as low cost and non-intrusive sensing, acoustic tomography (AT) is considered to be a promising visualization measurement method for temperature distribution. An SA-ELM algorithm was proposed to improve reconstruction quality of temperature distribution after AT measurement. First, robust estimation was used to establish the L1 norm objective functions. Then, the objective functions were solved to obtain temperature distribution on coarse discrete grids by simulated annealing algorithm (SA). Finally, temperature distribution on fine grids was predicted by extreme learning machine (ELM) method. Numerical simulations and experimental study showed that the SA-ELM method could improve quality and robustness of temperature distribution reconstruction. Hence, an effective new method is developed for solving reverse challenge in AT measurement.

    Reconstruction based semi-supervised ELM and its application in fault diagnosis
    YI Weilin, TIAN Xuemin, ZHANG Hanyuan
    2017, 68(6):  2447-2454.  doi:10.11949/j.issn.0438-1157.20161252
    Abstract ( 286 )   PDF (609KB) ( 411 )  
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    It is difficult to obtain labeled fault data while there are a multitude of unlabeled data available in industrial process, so how to utilize data information effectively is an important focal point in the field of fault diagnosis. A new semi-supervised learning method, reconstruction-based semi-supervised extreme learning machine (RSELM), was proposed for more sufficient data mining and information usage. Compared to traditional semi-supervised ELM, RSELM replaced random input weight in hidden layer with output weight, which was obtained by ELM auto-encoder (ELM-AE), such that data feature was extracterd more effectively. Since data could be reconstructed linearly by its neighbors, a self-adaptive reconstruction graph of neighboring data in combination with connection weight of optimal labeled data better reflected data structure information. A novel objective function preserving local structure information was further built to train classifier effectively. Simulation experiment on standard datasets and TE process demonstrated effectiveness of the proposed algorithm.

    Equilibrium optimization for high efficiency and low pollution combustion of power-generation boilers using game differential evolution algorithm
    ZHAO Minhua, HU Yi, LI Jin, WANG Yusheng, WU Rui, SONG Le
    2017, 68(6):  2455-2464.  doi:10.11949/j.issn.0438-1157.20161480
    Abstract ( 376 )   PDF (700KB) ( 409 )  
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    Improving thermal efficiency and reducing pollutant emissions such as NOx is a critical problem to be solved for conservation and emission reduction in power plant energy. A combustion optimization model was established by quantum genetic algorithm (QGA) optimized least squares support vector machine (LSSVM-QGA). The model predicted boiler thermal efficiency and NOx emissions at average relative error of 0.054% and 1.229%, respectively, which demonstrated high prediction accuracy, generalization ability and applicability. Based on the model, a method of differential evolution algorithm (DE) of self-adaptive scaling/crossover factors and sharing function followed by evolutionary Nash equilibrium was proposed for multi-objective optimization of boiler's combustion. Results show that optimization method based on NASH equilibrium can get optimal set of solutions to operational variables, which improve operating conditions and keep power generation boiler at a stable equilibrium state of combustion.

    OS-ELM-based hybrid online modeling for motor load torque of beam pumping units
    LI Kun, HAN Ying, LI Shenming, WANG Tong
    2017, 68(6):  2465-2472.  doi:10.11949/j.issn.0438-1157.20161194
    Abstract ( 293 )   PDF (787KB) ( 236 )  
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    Pumping motor with large electrical horsepower for small power-consuming equipment is commonly seen in beam pumping units, as it is difficult to understand exact relationship between motor working efficiency and complex dynamic loads. An online hybrid model for motor load torque under dynamic load changes was proposed by online sequential-extreme learning machine (OS-ELM) with a consideration of polished rod loads as the system's loads. First, mechanism models of each part in the pumping unit were separately built according to working principles of the system. Then, OS-ELM-based online soft sensor model was built to obtain value for a critical uncertain variable, the underground friction. Original structure of the soft sensor model was first set by offline training with historical production data and then online updated by a sliding window method. Therefore, the underground friction is no longer a constant value, which was given by any subjective experience in most other studies, but a dynamic value following system changes, which is more in line with actual operation conditions. The simulation results of proposed method on a normal oil well demonstrated validness and effectiveness.

    Rebounding and splashing behavior of single water droplet impacting on cold superhydrophobic surface
    LI Dong, WANG Xin, GAO Shangwen, CHEN Tong, ZHAO Xiaobao, CHEN Zhenqian
    2017, 68(6):  2473-2482.  doi:10.11949/j.issn.0438-1157.20161518
    Abstract ( 361 )   PDF (6223KB) ( 694 )  
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    Dynamic behavior of a single water droplet with 2.8 mm in diameter impacting on cold surface was visually observed by high speed camera, the evolutional characteristics of water droplet impacting on cold superhydrophobic and bare aluminum surfaces were comparatively studied. Besides, the effect of initial impacting velocity and cold surface temperatures on the dynamic behavior of water droplet on cold surface were analyzed. The experimental result showed that compared with the instantly freezing of water droplet impacting on cold bare aluminum surface, the water droplet impacting on cold superhydrophobic surface (-25—-5℃) can not freeze along with spreading, retraction, rebound and smash behaviors. The higher the impacting velocity is, the bigger the spreading factor is and the more easily the water droplet freezes on cold bare aluminum surface. Moreover, rebounding behavior can be found when droplet impacts on the superhydrophobic surface with a low speed (We≤76) and velocity has no effect on the maximum spreading time. Also, obvious droplet fingers will appear and can be fragmented into many satellite droplets as droplet impacts on cold superhydrophobic surface with a high speed (We≥115). In addition, cold surface temperature has obvious effect on rebounding height but has little effect on the spreading factor and spreading time. The results indicate that the superhydrophobic surface can prevent the water droplet effectively from freezing instantly as the droplet impacts on cold surface.

    Non-equilibrium sorption kinetic models of SrCl2 and its application for refrigeration
    AN Guoliang, WANG Liwei, ZHOU Zhisong, JIANG Long, WANG Ruzhu
    2017, 68(6):  2483-2490.  doi:10.11949/j.issn.0438-1157.20161310
    Abstract ( 320 )   PDF (558KB) ( 267 )  
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    To research the non-equilibrium sorption kinetic models of SrCl2 compound sorbents-NH3 working pairs, the sorption and desorption performance of SrCl2-expanded natural graphite treated with sulfuric acid (ENG-TSA) composite sorbents with the ratio of 4:1 (SrCl2:ENG-TSA) is tested and researched. Results show that the non-equilibrium sorption processes are controlled by two variables other than single variable. Then, the isobaric sorption/desorption processes and the hysteresis phenomena were analyzed, and the kinetic models were established. The refrigeration performance of composite sorbents is studied, and the corresponding COP and theoretical refrigerating capacity are analyzed by equilibrium data, experimental data, and modelling data, respectively. The results show that the established kinetic model fit the experimental data well. For instance, compared with the experimental data the error of COP by the established kinetic model is less than 1%, while that value by theoretical equilibrium data is 25.8% (under the condition of evaporating temperature of 0℃, environmental temperature of 25℃, and heating temperature higher than 90.5℃). The system refrigerating capacity obtained by theoretical equilibrium data is 188.1% higher than that gotten from the experimental data, while the value by kinetic model is just 2.1%.

    Drying characteristics of deep dewatered sludge
    WANG Jiaxing, LIU Huan, LIU Peng, ZHANG Qiang, LU Geng, HU Hongyun, YAO Hong
    2017, 68(6):  2491-2500.  doi:10.11949/j.issn.0438-1157.20170069
    Abstract ( 314 )   PDF (2007KB) ( 610 )  
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    Composite conditioners in deep-dewatered sludge have an important influence on its drying characteristics. In order to obtain deep-dewatered sludge, the raw sludge was pretreated by four kinds of typical composite conditioners and then dewatered. At the N2 atmosphere and 473 K, the effects of the composite conditioners on the emission characteristics of moisture and pollutants, as well as the drying products properties of gas, liquid and solid phase, were investigated. The results showed that the composite conditioner could effectively reduce the water content of dewatered sludge and accelerate the water release, shorting the drying time as well. Conditioning process in the acid, alkali and strong oxidizing environment destroyed the organic structure of sludge so that the aromatic-or thiophene-S in sludge could transfer into more stable sulfonic acid-or sulfone-S. Also, the alkaline environment allowed the dissolved acidic sulfur-containing gas to be fixed, thereby reducing the amount of sulfur-containing gas released during drying. But the releasing rate of ammonia was accelerated. Because of the high concentration of sulfur-containing gases, nitrogen-containing gases and volatile organic compounds in the drying exhaust gas, the condensate had a high pH and COD accompanied by malodor, and thus needed to be disposed before it can be discharged. The lower heating value of sludge can be 6.79—13.18 kJ·g-1 of dry sludge and efficiently maintained under the drying temperature of 473 K so that the dried sludge can provide a kind of renewable energy.

    Life-cycle greenhouse gas emissions and cost of potassium extraction and CO2 mineralization via K-feldspar—industrial solid waste calcination
    MO Chun, LIAO Wenjie, LIANG Bin, LI Chun, YUE Hairong, XIE Heping
    2017, 68(6):  2501-2509.  doi:10.11949/j.issn.0438-1157.20161754
    Abstract ( 540 )   PDF (916KB) ( 512 )  
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    Using industrial solid waste to calcinate non-water-soluble natural K-feldspar for CO2 mineralization and potassium extraction is a multi-functional CO2 capture, utilization and storage (CCUS) technology that can treat industrial solid waste, utilize potassium resource and reduce greenhouse-gas (GHG) emissions. Life cycle assessment (LCA) was adopted based on a functional unit of the produced potash fertilizer containing 1 ton of K2O to compare two emerging technologies of simultaneous potash fertilizer production and CO2 mineralization from K-feldspar and industrial solid waste (CaCl2/phosphor-gypsum) with a traditional technology of potash fertilizer and white cement coproduction by smelting K-feldspar in blast furnace in terms of GHG-reduction potential and economic feasibility. The life-cycle (from raw material exploitation to transportation to production) GHG emissions and life-cycle cost of these technologies were accounted by using an improved allocation approach that considered the credit of avoided GHG emissions/cost from industrial solid waste treatment. The results showed that the two emerging technologies were preferred to the traditional technology in terms of both life-cycle GHG emissions and economic feasibility with GHG-reduction potential of about 81.16% and 20.48%, and cost savings of up to 34.75% and 45.11%, respectively.

    Characterization and analysis of textile sludge char from moving bed pyrolyser under microwave irradiation
    ZHANG Hedong, GAO Zuopeng, AO Wenya, FU Jie, RAN Chunmei, MAO Xiao, KANG Qinhao,LIU Yang, LIU Guangqing, CHEN Xiaochun, DAI Jianjun
    2017, 68(6):  2510-2518.  doi:10.11949/j.issn.0438-1157.20170003
    Abstract ( 347 )   PDF (2269KB) ( 510 )  
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    The paper investigated pyrolysis of textile sludge in a moving bed pyrolyser under microwave irradiation. Microwave power, temperature, gas and solid residence times, and catalysts were studied. Elemental analysis, scanning electron microscopy (SEM), BET surface area analysis, X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) were conducted and analyzed. It showed that the sludge char (SC) yield decreased and non-condensable gas yield increased as temperature increased. At 750℃, the SC yield was 63.87%(mass). Addition of CaO and Fe increased SC yield, and the H2, CO and CH4 contents, and decreased CO2 content in the non-condensable gas. Maximum H2 content was up to 64.17%. The contents of C, H and O in SC decreased as temperature increased, while S content increased. The BET surface area reached the maximum at 550℃, which was consistent with the SEM observation. The ICP-MS results showed that the heavy metals in SC met the requirements of emissions standards in China. The moving bed pyrolyser under microwave irradiation provided a promising prospect to efficiently treat and dispose TS.

    Numerical simulation of co-combustion of coal and refuse derived fuel in coupling with decomposition of calcium carbonate in precalciner with swirl type prechamber
    MEI Shuxia, XIE Junlin, CHEN Xiaolin, LI Xuemei, PEI Kepeng, HE Feng
    2017, 68(6):  2519-2525.  doi:10.11949/j.issn.0438-1157.20170028
    Abstract ( 424 )   PDF (1119KB) ( 384 )  
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    Numerical simulation of co-combustion of pulverized coal, refuse derived fuel (RDF) and thermal decomposition of calcium carbonate was carried out aiming at an actual precalciner with swirl type prechamber. The predicted burn-off rates of pulverized coal and RDF were 99% and 100% respectively,and the predicted decomposing rate of calcium carbonate was 95%, being in accordance with engineering data actually measured. The results show that the fuel and raw meal are carried by gas stream to rise spirally. The pulverized coal stream starts to burn soon when injected into the furnace from the top of the prechamber, and then burns rapidly, being dominated by char combustion, when rising into the cone section and the column section above the prechamber, forming a violent combustion region. The RDF starts to burn soon, being dominated by volatile combustion, when blown into the furnace horizontally from the lower part of the column section of the precalciner, forming a main combustion zone, and then rises spirally intertwining with the pulverized coal stream. The calcium carbonate begins to whirl in the prechamber, being decomposed by absorbing the heat of high-temperature gas stream, when falling into the furnace from the top of the prechamber, and then is further decomposed in the main combustion zone of coal and RDF on the way up. As a result of the coupling of co-combustion and decomposition, there is a uniform and steady temperature field in the column section of the precalciner.

    Cyclohexane assisting preparation of starch esterification in supercritical CO2
    LI Xidu, XIE Xinling, ZHANG Youquan, JU Quanliang
    2017, 68(6):  2526-2534.  doi:10.11949/j.issn.0438-1157.20170060
    Abstract ( 311 )   PDF (1630KB) ( 313 )  
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    Auxiliary effect of additives, such as cyclohexane, in supercritical CO2 fluid on the preparation of octenyl succinic acid cassava starch was investigated, and the types of additives, volume rate of additive to supercritical CO2, amount of esterification agent, reaction temperature, pressure and reaction time on the effect of degree of substitution and reaction efficiency were explored in a bath reactor set-up. The NMR, SEM and XRD were used to examine esterification groups, particle surface morphology and crystalline structure. The results revealed that the additive could improve the solubility of the supercritical CO2 medium to esterification agent, and the cyclohexane additive showed the optimal synergistic effect with reaction efficiency of about 3.0 times higher than that without the additive when 1.5% cyclohexane was added. Meanwhile, the optimum reaction conditions were found as follows: reaction temperature of 90℃, pressure of 12 MPa, time of 3 h and esterification agent of 4% with the degree of substitution and the reaction efficiency are 0.0191 and 61%, respectively, and even the reaction efficiency was up to 83% by using 2% esterification agent. Analysis of product structure characterization showed that the esterification groups were introduced into the starch molecules, and small particle characteristics and A-type crystal structure were still remained, but the particle surface morphology was partially destroyed and the crystallinity was reduced. All the results indicated that the cyclohexane can increase reaction efficiency and improve esterification reaction condition.

    Optimization treatment of sludge heavy metals by citric acid and GLDA
    XU Dayong, HONG Yajun, TANG Hai, CHENG Weiming, SONG Zhenxia,ZHAN Lingling, YAO Qiaofeng
    2017, 68(6):  2535-2545.  doi:10.11949/j.issn.0438-1157.20170001
    Abstract ( 284 )   PDF (1642KB) ( 356 )  
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    High heavy metals content is the major drawback of sludge resource, especially for sludge derived from industrial wastewater treatment plan. Citric acid and GLDA were used to treat sludge heavy metals in the present study, and the effects of the reagent concentration, pH and reaction time of citric acid and GLDA on the availability and removal of sludge heavy metals were investigated. An orthogonal experiment was performed to obtain the optimum reaction condition of CA and GLDA treatment of the sludge heavy metals. The results indicated that the higher reagent concentrations and the lower pH led to the higher removal rate of heavy metals, but the effect of longer reaction time on heavy metal removal was not obvious. The best conditions of CA andGLDA treatment of sludge heavy metals were: CA 0.3 mol·L-1, pH 4 and reaction time 2 h, and GLDA 0.05 mol·L-1, pH 4 and reaction time 3 h. Under the optimum reaction conditions of the CA and GLDA, the removal rate of Cd, Cu, Pb and Ni can reach 80.25%, 77.75%, 64.66% and 75.16%, and 78.57%, 78.48%, 64.84% and 76.71%, respectively. Both of CA and GLDA, the removal efficiency of heavy metals was ranged as Cd>Cu> Ni>Pb, but the effect of GLDA treatment was better than that of CA. After CA and GLDA treatment, the acid-soluble contents of heavy metals in the solid phase of sludge decreased most and reached an average of 81%, the residual contents decreased an average of 52.1%, and the heavy metals in the liquid phase of sludge increased an average of 17.54 times, leading to the transfer of the heavy metals from the solid phase into liquid phase. SEM observation showed that the flocculent structure of sludge was replaced obviously by mass structure and the layered structure after treatment. And at the same time, the adsorption ability and volume were reduced. The research results showed that the CA and GLDA treatment of sludge can effectively reduce the sludge heavy metal content and improve the chemical stability of heavy metals in solid phase of sludge, which was advantageous to the sludge dehydrating and its further processing and utilization.

    Purification of methanol wastewater by non-thermal plasma combined with packed bed adsorption
    SHENG Nan, CHEN Minggong, SUN Yimei, RONG Junfeng, WEI Zhouhaosheng, XU Yin
    2017, 68(6):  2546-2554.  doi:10.11949/j.issn.0438-1157.20161385
    Abstract ( 448 )   PDF (627KB) ( 378 )  
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    The purification process of high concentration methanol wastewater intensified by non-thermal plasma(NTP) combined with packed adsorption bed had been investigated. The results showed that the four types of packed bed materials, 4A molecular sieves, ceramsite, ceramic Rasching ring and γ-Al2O3, could adsorb methanol rapidly, but reached the adsorption saturation easily. The adsorption velocity and equilibrium absorption capacity of 4A molecular sieves was better than the others. In the multi-needle-plate DBD (dielectric barrier discharge) non-thermal plasma purification system, the degradation rate of COD increased with increasing discharge time and discharge voltage. The degradation effect of NTP combined with packed bed was better than single purification process. In the initial reaction stage of combination process, the rapid degradation of COD was dominated by packed bed adsorption process. However, NTP played a main role in the degradation process with prolongation of discharge time. The methanol, both in liquid phase and adsorbed in packed bed, had been oxidized by active groups which generated by NTP. The maximum degradation rate of COD was more than 90% in this experiment. The adsorption process of packed bed followed the pseudo-second order adsorption kinetic equation. The reaction order of NTP degradation process increased with the decline of pollutant concentration and the prolongation of discharge time. In the synergistic purification system, the adsorption process of packed bed would be influenced by NTP, and vice versa. The active groups generated by NTP had an activating effect on the contaminant, both in liquid phase and adsorbed in packed bed. Therefore, the concentration ratio of contaminant and hydroxyl radical(·OH) in liquid phase would be changed constantly under the process of packed bed adsorption and NTP oxidation. The reaction order of macroscopic reaction kinetics of synergistic process increased with the decrease of methanol concentration in liquid phase.

    CO2 absorption by aqueous ammonia solution with use of external magnetic field
    ZHANG Qi, WU Jiayi, LU Ping, WU Tao, SHAO Jingping, DENG Xiaoyan
    2017, 68(6):  2555-2562.  doi:10.11949/j.issn.0438-1157.20161596
    Abstract ( 316 )   PDF (555KB) ( 409 )  
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    A novel ammonia-based CO2 capture process was proposed in the paper. The process uses magnetically gas-solid-liquid bed as the reactor in which the ferromagnetic particles suspend in aqueous ammonia solutions under the influence of external magnetic field (EMF). A continuous of CO2 passed through the reactor was absorbed by aqueous ammonia. Experiments in a laboratory-scale apparatus were carried out to investigate the roles of EMF. The results showed that the highest CO2 absorption efficiency with 8 mT EMF and 2 g·L-1 nano-magnetic particles reached 94.3%, more than 8.8% compared to that without EMF and nanoparticles. CO2 absorption efficiency with EMF and nanoparticles increased significantly under the conditions of low concentration aqueous ammonia (5%—8%), large flux of simulated flue gas (3.5 L·min-1) and low absorption temperature (22—36℃). The enhancement of CO2 absorption under the influence of EMF and nanoparticles should be attributed to good gas-liquid contact, large mass transfer coefficient and high reactivity of aqueous ammonia.

    Experimental characteristics of ice preparation via Cu-nano fluid's vacuum flash
    ZHANG Xuelai, LI Yue, WANG Zhangfei, JIA Xiaoya
    2017, 68(6):  2563-2568.  doi:10.11949/j.issn.0438-1157.20161525
    Abstract ( 284 )   PDF (396KB) ( 323 )  
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    Cu nanoparticles were added into the deionized water with dispersant and ultrasonic wave to prepare the dispersive Cu-H2O nano fluid. The effect of nano fluid on the characteristics of vacuum flash ice preparation by changing the particle size and the mass fraction of nano fluid under the 100 Pa was explored experimentally. As the results showed, adding nano particles into water without dispersant (nano particles have settling phenomenon), can reduce the supercooling degree of water, and shorten the time of phase change. However the uniform dispersion of nano fluid without settlement can significantly shorten the time of phase change, and the supercooling degree is reduced by 37%. At the initial flash moment, nano fluid has little effect on the cooling process of liquid phase. The larger the mass fraction of the nano fluid, the shorter the icing time, and the greater the cooling rate of the solid phase. The phase transformation time is shortened with the decrease of the particle size, but the temperature drop rate is almost the same in the solid phase. The change of particle size has little effect on the supercooling degree of the solution, which is basically maintained at 1.5℃ at lower concentration.

    Synthesis of poly(vinyl chloride)-b-poly(ethylene glycol)-b-poly(vinyl chloride) block copolymers by reversible addition-fragmentation chain transfer polymerizations
    HUANG Zhihui, BAO Yongzhong, PAN Pengju
    2017, 68(6):  2569-2576.  doi:10.11949/j.issn.0438-1157.20170011
    Abstract ( 377 )   PDF (1275KB) ( 391 )  
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    Poly(ethylene glycol) terminated with xanthate (X-PEG-X) was synthesized and used as the reversible addition-fragmentation chain transfer (RAFT) agent for controlling vinyl chloride (VC) solution and suspension polymerizations to synthesize poly(vinyl chloride)-b-poly(ethylene glycol)-b-poly(vinyl chloride) (PVC-b-PEG-b-PVC) triblock copolymers. Results show that the molecular weights (MW) of block copolymers prepared by the solution polymerization are increased with the polymerization conversion, and the molecular weight distribution (MWD) index is lower than 1.65. X-PEG-X is amphiphilic and can effectively reduce the interfacial tension between water and oil. Thus, a novel VC RAFT suspension polymerization method was proposed to prepare PVC-b-PEG-b-PVC copolymers using X-PEG-X as the RAFT agent and a suspending agent. The block copolymer particles have no surface membranes, and MW of copolymer is increased with conversion. However, the block copolymers prepared by suspension polymerization exhibit wider MWD than the block copolymers prepared by solution polymerization, due to the two-phase mechanism of VC suspension polymerization. The chain extension of PVC-b-PEG-b-PVC with vinyl acetate (VAc) further prove the “living” nature of PVC-b-PEG-b-PVC copolymers and result the formation of PVAc-b-PVC-b-PEG-b-PVC-b-PVAc copolymer. PVC-b-PEG-b-PVC copolymers exhibit better hydrophilicity than PVC.

    Adsorption behavior of Fe(Ⅲ) on PDA/RGO composites
    LI Chuang, WANG Caiyun, JIANG Tingting, WANG Manli, ZHANG Xiaoliang
    2017, 68(6):  2577-2584.  doi:10.11949/j.issn.0438-1157.20170048
    Abstract ( 359 )   PDF (858KB) ( 505 )  
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    The bio-inspired polydopamine/reduced graphene oxide (PDA/RGO) composites were prepared by grafting dopamine with graphene oxide nanosheets. The structure and surface properties of the as-synthesized composites were characterized by X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The adsorption behavior and properties of aqueous Fe(Ⅲ) on the PDA/RGO composites were also investigated. The effects of pH, adsorbent amounts, adsorption time, initial concentration of Fe(Ⅲ) and temperature on adsorption properties were investigated in details. From these characterization results, it was indicated that dopamine and graphene oxide could be successfully produced to PDA/RGO composites via the bio-inspired self-assembly. The PDA/RGO composites showed high adsorption performance for aqueous Fe(Ⅲ). The maximum adsorption capacity of 59.1 mg·g-1 for Fe(Ⅲ) on the PDA/RGO composites was obtained at 293 K and pH of 2. The adsorption isotherm of Fe(Ⅲ) on the PDA/RGO composites could be described better with Freundlich equation model than Langmuir model, and the pseudo-second-order kinetics equation fitted well with the adsorption data. The adsorption process for Fe(Ⅲ) on the PDA/RGO composites was an exothermic and spontaneous, exhibiting heterogeneous adsorption characteristics. As a kind of new adsorption materials, the PDA/RGO composites will have potential application in wastewater treatment containing metals such as Fe(Ⅲ).

    Regulation of graphene oxide on microstructure of cement composites and its impact on compressive and flexural strength
    LÜ Shenghua, ZHANG Jia, ZHU Linlin, JIA Chunmao
    2017, 68(6):  2585-2595.  doi:10.11949/j.issn.0438-1157.20161575
    Abstract ( 505 )   PDF (14213KB) ( 467 )  
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    Graphene oxide (GO) was prepared by oxidation, and the intercalation composite of GO/P(AA-AM) was prepared by intercalation polymerization of GO with acrylic acid(AA) and acrylamide (AM). The testing results indicated that GO nanosheets in the GO/P(AA-AM) had smaller size and uniform dispersion. Meanwhile, it is found that GO nanosheets can regulate the cement hydration products to form regular needle-like, rod-like, or polyhedron-like crystal, also ordered microstructure and macrostructure. The cracks and harmful pores in the cement composites have obviously decreased. The compressive and flexural strength have significant increase compared with the control samples. The regulation mechanism of GO nanosheets on cement hydration crystals and the microstructure of cement composites were proposed. It thinks that GO nanosheets with active chemical groups have the promoting and template effects on forming regular shapes of cement hydration crystals. The initial regular crystals play a template role for later formed crystals, and finally form large-volume and regular shape crystals and ordered microstructure and macrostructure by crystals growing.

    Preparation and lithium storage performance of nanoporous hollow microspheres-like NiO anode materials
    ZHENG Yuanyuan, YAO Jinhuan, JIANG Jiqiong, LI Yanwei
    2017, 68(6):  2596-2603.  doi:10.11949/j.issn.0438-1157.20161840
    Abstract ( 323 )   PDF (3151KB) ( 393 )  
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    Using NiCl2·6H2O, urea, and glucose as materials, hollow microspheres-like NiO were prepared by hydrothermal method followed by annealing in air at 700℃. The results of microstructural characterization reveal that the hollow microspheres-like NiO are composed of nanosized primary particles (50—100 nm). The electrochemical performances of the prepared NiO samples were investigated. It is found that the pseudocapacitive effect has a prominent contribution to the lithium storage capacity of the NiO electrode. Due to the unique hollow structure and pseudocapacitive effect, the NiO electrode shows outstanding electrochemical cycling stability and excellent high rate capability. For example, the NiO electrode retains a high reversible capacity of 650 mA·h·g-1 after 100 cycles at a current density of 500 mA·g-1. Even at ultra-high current density of 10 A·g-1, the NiO electrode can still deliver a capacity of 432 mA·h·g-1.

    Synthesis of novel boron containing benzoxazine and its thermal properties with epoxy resin blends
    CHEN Yang, SHI Tiejun, QIAN Ying, HE Tao
    2017, 68(6):  2604-2610.  doi:10.11949/j.issn.0438-1157.20161816
    Abstract ( 326 )   PDF (506KB) ( 316 )  
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    The boric acid ethanolamine ester (BAE) was synthesized using boric acid and ethanolamine. The synthesis of benzoxazine contained boron (BAE-BOZ) was synthesized by using BAE, phenol and paraformaldehyde. The BAE-BOZ are mixed with epoxy resin in different proportions, and then cured by high temperature. Using FT-IR, 1H NMR and 13C NMR analysis of the chemical structure of BAE-BOZ, proved that the target product has been synthesized. Curing properties on BAE-BOZ was studied with DSC, the thermal stability of poly(BAE-BOZ) cured BAE-BOZ/E-51 were studied by using TG analysis. The results showed that the curing peak of BOZ appeared at 218℃, B and oxazine ring were combined by B O C, and the highest the boric content in BAE-BOZ was 8.67%, the initial pyrolysis temperature was about 302℃, and the carbon residual at 800℃ increased from 41.80% to 58.08%. The thermal decomposition temperature of BAE-BOZ/E-51 copolymer reached 343℃.

    Synthesis of Cu2O nanoparticles in T-shaped micro-mixer
    REN Zhengling, LU Chenyang, WANG Anjie, WANG Yao
    2017, 68(6):  2611-2617.  doi:10.11949/j.issn.0438-1157.20170024
    Abstract ( 298 )   PDF (3343KB) ( 502 )  
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    A facile controllable route for preparing cubic cuprous oxide (Cu2O) nanoparticles in T-shaped micro-mixer was developed by precipitation technique using copper chloride as copper source, sodium hydroxide as precipitant and ascorbic acid as reducing agent. The influences of feed flow rate, sodium hydroxide concentration, ascorbic acid concentration and temperature on morphology, size and size distribution of Cu2O nanoparticles were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible spectrophotometry (UV-Vis). The results showed that size of Cu2O particles became smaller and size distribution became narrower with the decrease of sodium hydroxide concentration and the increase of feed flow rate, ascorbic acid concentration and temperature.