PDMS/陶瓷复合膜用于正丁醇-水体系的渗透汽化分离

Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation per-formance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40 C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g•m2•h1 and 26.1, respec-tively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.     

用CuO/A12O3/堇青石催化剂选择性催化还原脱硝的实验和动力学研究

The CuO/γ-Al2O3/cordierite catalyst, after being sulfated by sulfur dioxide (SO2) at 673 K, exhibits high activities for selective catalytic reduction (SCR) of nitrogen oxide (NO) with ammonia (NH3) at 573-723 K. The intrinsic kinetics of SCR of NO with NH3 over CuO/γ-Al2O3/cordierite catalyst has been measured in a fixed-bed reactor in the absence of internal and external diffusions. The experimental results show that the reaction rate can be quantified by a first-order expression with activation energy of 94.01 kJ•mol1 and the corresponding pre-exponential factor of 3.39×108 cm3•g1•s1 when NH3 is excessive. However, when NH3 is not enough, an Eley-Rideal kinetic model based on experimental data is derived with Ea of 105.79 kJ•mol1, the corresponding A of 2.94×109 cm3•g1•s1, heat of adsorption ΔHads of 87.90 kJ•mol1 and the corresponding Aads of 9.24 cm3•mol1. The intrinsic kinetic model obtained was incorporated in a 3D mathematical model of monolithic reactor, and the agreement of the prediction with experimental data indicates that the present kinetic model is adequate for the reactor design and engineering scale-up.     

氨改性的介孔二氧化硅的直接合成和CO2吸附

Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the SN+-I mechanism and applied to CO2 adsorption at room temperature. With γ-aminopropyltriethoxysilane as co-structure directing agent and due to the direct electrostatic interaction with anionic surfactant, most of the amino groups were uniformly distributed at the inner surface of pores and the performance was stable. The amine-functionalized mesoporous silica was characterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogen physisorption and thermogravimetric analysis. The CO2 adsorption capacity was measured by digital recording balance. At the room temperature and under the atmospheric pres-sure, the adsorption capacity of LAA-AMS-0.2 for CO2 and N2 is 1.40 mmol•g1 and 0.03 mmol•g1, respectively, indicating high separation coefficient of CO2/N2.     

P507溶于煤油作为载体的一种新型分散组合液膜对Eu3+的分离

The separation of Eu3+ is studied with a dispersion combined liquid membrane (DCLM), in which polyvinylidene fluoride membrane (PVDF) is used as the liquid membrane support, dispersion solution containing HCl solution as the stripping solution, and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (P507) dissolved in kerosene as the membrane solution. The effects of pH value, initial concentration of Eu3+ and different ionic strength in the feed phase, volume ratio of membrane solution to stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on the separation are investigated. The optimum condition for separation of Eu3+ is that concentration of HCl solution is 4.0 mol•L1, concentration of carrier is 0.16 mol•L1, and volume ratio of membrane solution to stripping solution is 30︰30 in the dispersion phase, and pH value is 4.2 in the feed phase. The ionic strength has no significant effect on separation of Eu3+. Under the optimum condition, when the initial concentration of Eu3+ is 0.8×104 mol•L1, the separation percentage of Eu3+ is 95.3% during the separation time of 130 min. The kinetic equation is developed in terms of the law of mass diffusion and the theory of interface chemistry. The diffusion coefficient of Eu3+ in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and their values are 1.48×107 m2•s1 and 36.6 μm, respectively. The results obtained are in good agreement with literature data.     

利用两级UASB消化处理实现木薯燃料乙醇的水循环型生产

Considering limited success in target-hitting discharge from alcohol industry, our attention was directed toward a recycling use of distillery spentwash (DS) in cassava bioethanol production by using a two-stage up-flow anaerobic sludge blanket bioremediation (TS-UASBB). With the TS-UASBB, , COD, N and P in the effluent from the DS degraded significantly and their concentrations were kept at 0.2 g•L1, 2.0 g•L1, 1.0 g•L1 and 15 mg•L1, respectively, in 13 batch processes for water-recycled ethanol fermentation. With the effluent used directly as dilution water, no heat-resistant bacteria were found alive. The thirteen-batch ethanol production individually achieved 10% after 48 h fermentation. The starch utilization ratio and total sugar consumption were 90% and 99.5%, respectively. The novel water-recycled bioethanol production process with ethanol fermentation and TS-UASBB has a considerable potential in other starchy and cellulosic ethanol production.     

硫酸铁改性颗粒活性氧化铝除氟的等温线研究

The adsorption equilibrium of a fluoride solution on 1-2 mm granular activated alumina modified by Fe2(SO4)3 solution was investigated. The experiments were conducted using a wide range of initial fluoride concentrations (0.5 to 180 mg•L1 at pH ~7.0) and an adsorbent dose of 1.0 g•L1. The application of Langmuir and Freundlich adsorption isotherm models (linear and nonlinear forms) generally showed that a single Langmuir or Freundlich equation cannot fit the entire concentration gap. Experimental data on low equilibrium concentrations (0.1 to 5.0 mg•L1) was in line with both Langmuir and Freundlich isotherm models, whereas that of high equilibrium concentrations (5.0 to 150 mg•L1) was more in line with the Freundlich isotherm model. A new Langmuir- Freundlich function was used for the entire concentration gap, as well as for low and high concentrations.     

响应面方法分析代谢产物对类人胶原蛋白表达的影响

Recombinant Escherichia coli BL21 is used to produce human-like collagen. The key constituents of media are optimized using response surface methodology (RSM). Before thermal induction, the highest biomass production and the lowest production of some hazardous by-products, especially acetic acid, were obtained in the media containing 0.085 mol∙L1 glucose and 0.019 mol∙L1 nitrogen (carbon-nitrogen ratio, 4.47︰1). After thermal induction, when the concentrations of glucose and nitrogen in the media were 0.065 mol∙L1 and 0.017 mol∙L1, respectively (carbon-nitrogen ratio, 3.82︰1), the productivity of human-like collagen per cell was the highest while that of acetic acid was the lowest. The extended analysis showed that the production of lactic acid and propionic acid increased while that of some intermediate acids of the tricarboxylic acid cycle decreased if the dose of glucose in-creased.     

突变株CTM2降解苯酚和4-氯酚的生物降解特性

The biodegradations of phenol and 4-chlorophenol (4-cp) were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that the capacity of the CTM 2 to biodegrade 4-cp was increased up to 400 mg•L－1 within 59.5 h. In the dual-substrate biodegradation, both velocity and capacity of the CTM 2 to degrade 4-cp increased with low-concentration phenol. A total of 400 mg•L－1 4-cp was completely degraded within 50.5 h in the presence of 300 mg•L－1 phenol. The maximum 4-cp biodegradation could reach 440 mg•L－1 with 120 mg•L－1 phenol. Low-concentration 4-cp caused great inhibition on the CTM 2 to degrade phenol. In addition, the kinetic behaviors were described using the kinetic model proposed in this lab.     

面包酵母No.6催化不对称合成(2S,5S)-2,5-已二醇反应特性

Baker’s yeast number 6 was selected by screening. It showed good catalytic activity and enantioselectivity for asymmetric reduction of 2,5-hexanedione to produce (2S,5S)-2,5-hexanediol. Gas chromatography-mass spectrometry (GC-MS) revealed that the intermediate was (S)-5-hydroxyhexane-2-one. Reduction of 2,5-hexanedione proceeded in a two-step reaction. The hydroxyketone was initially formed, and this intermediate was further re-duced to the diol. Factors influencing the product yield and the enantiomeric excess of the reduction of 2,5-hexandione catalyzed by baker’s yeast number 6 were investigated. Higher concentration (≤100 mmol•L－1) of 2,5-hexandione did not influence 5-hydroxyhexane-2-one production, but 2,5-hexanediol production was inhibited by excess accumulation (＞30 mmol•L－1) of intermediate. The optimal conditions were glucose as the co-substrate at an initial glucose concentration of 20 g•L－1, 34C, pH 7.0 and cell concentration 60 g•L－1 (cell dry mass). Under the optimal condition and an initial substrate concentration of 30 mmol•L－1, the yield of 2,5-hexandiol was 78.7% and the enantiomeric excess of (2S,5S)-2,5-hexandiol was 94.4% for 24-h reduction.     

DMFCs用SPEEK/SiOx-S复合质子交换膜

A sulfonated poly(ether ether ketone) (SPEEK) membrane with a fairly high degree of sulfonation (DS) can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups (SiOx-S) was added into the SPEEK matrix (DS 55.1%) to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80°C, whereas the SPEEK/SiOx-S (15%, by mass) membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that of Nafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiOx-S (20%, by mass) membrane could withstand temperature up to 145°C, at which in 100% relative humidity (RH) its proton conductivity exceeded slightly that of Nafion115 membrane and reached 0.17 S•cm－1, while pure SPEEK mem-brane dissolved at 90°C. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.     

Carbon formation and its influence on ethanol steam reforming over Ni/Al2O3 catalysts

Ethanol steam reforming was studied over Ni/Al₂O₃ catalysts. The effect of support (- and γ-Al₂O₃), metal loading and a comparison between conventional H₂ reduction with an activation method employing a CH₄/O₂ mixture was investigated. The properties of catalysts were studied by N₂ physisorption, X-ray diffraction (XRD) and temperature programmed reduction (TPR). After activity tests, the catalysts were analyzed by scanning electron microscopy (SEM) and thermogravimetric analysis (TG/DTA). Ni supported on γ-Al₂O₃ was more active for H₂ production than the catalyst supported on -Al₂O₃. Metal loading did not affect the catalytic performance. The alternative activation method with CH₄/O₂ mixture affected differently the activity and stability of the Ni/γ-Al₂O₃ and the Ni/-Al₂O₃ catalyst. This activation method increased significantly the stability of Ni/-Al₂O₃ compared to H₂ reduction. SEM and TG/DTA analysis indicate the formation of filamentous carbon during the CH₄/O₂ activation step, which is associated with the increasing catalyst activity and stability. The effect of temperature on the type of carbon formed was investigated; indicating that filamentous coke increased activity while encapsulating coke promoted deactivation. A discussion about carbon formation and the influence on the activity is presented.     

High-performance SSZ-13 membranes prepared using ball-milled nanosized seeds for carbon dioxide and nitrogen separations from methane

SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis. Separation performances of SSZ-13 membranes in CO_2/CH_4 and N_2/CH_4 mixtures were enhanced after synthesis modification. Single-gas permeances of CO_2, N_2 and CH_4 and ideal selectivities were recorded through SSZ-13 membranes. The effects of temperature, pressure, feed flow rate and humidity on separation performance of the membranes were discussed. Three membranes prepared after synthesis modifications had an average CO_2 permeance of 1.16 × 10~(-6) mol·(m~2· s·Pa)~(-1)(equal to 3554 GPU) with an average CO_2/CH_4 selectivity of 213 in a 50 vol%/50 vol% CO_2/CH_4 mixture. It suggests that membrane synthesis has a good reproducible. The membrane also displayed a N_2 permeance of 1.07 × 10~(-7) mol·(m~2·s·Pa)~(-1)(equal to 320 GPU) with a N_2/CH_4 selectivity of 13 for a 50 vol%/50 vol% N_2/CH_4 mixture. SSZ-13 membrane displayed stable and good separation performance in the wet CO_2/CH_4 mixture for a long test period over 100 h at 348 K. The current SSZ-13 membranes show great potentials for the simultaneous removals of CO_2 and N_2 in natural gas purification as a facile process suitable for industrial application.     

焙烧温度对Al2O3载体的性质及其负载的煤制合成气制代用天然气镍基催化剂性能的影响

以拟薄水铝石为前驱体,经不同温度焙烧制得Al₂O₃载体,等体积浸渍法制备Ni/Al₂O₃催化剂,采用X射线衍射、N₂-物理吸附、扫描电镜、程序升温还原等对载体及催化剂进行表征,考察载体焙烧温度对Al₂O₃载体性质及其负载的镍基催化剂催化性能的影响。结果表明,随着焙烧温度的升高,Al₂O₃载体的比表面积减小,平均孔径增大,结晶度升高,晶粒度增大,晶型逐步转变为γ-Al₂O₃［(500~800) ℃］、δ-Al₂O₃［ (900~1 100) ℃］和α-Al₂O₃［(1 250) ℃］。合成气制甲烷催化剂活性变化趋势为:Ni/γ-Al₂O₃>Ni/δ-Al₂O₃>Ni/α-Al₂O₃,其中,800 ℃焙烧的γ-Al₂O₃负载的Ni基催化剂因稳定的晶型结构以及与NiO之间适当的相互作用而表现出最佳的催化活性及稳定性。     

Mechanistic study of partial oxidation of methane to synthesis gas over supported rhodium and ruthenium catalysts using in situ time-resolved FTIR spectroscopy

In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane to synthesis gas and the interaction of CH₄/O₂/He (2/1/45) gas mixture with adsorbed CO species over SiO₂ and γ-Al₂O₃ supported Rh and Ru catalysts at 500–600°C. It was found that CO is the primary product for the reaction of CH₄/O₂/He (2/1/45) gas mixture over H₂ reduced and working state Rh/SiO₂ catalyst. Direct oxidation of methane is the main pathway of synthesis gas formation over Rh/SiO₂ catalyst. CO₂ is the primary product for the reaction of CH₄/O₂/He (2/1/45) gas mixture over Ru/γ-Al₂O₃ and Ru/SiO₂ catalysts. The dominant reaction pathway of CO formation over Ru/γ-Al₂O₃ and Ru/SiO₂ catalysts is via the reforming reactions of CH₄ with CO₂ and H₂O. The effect of space velocity on the partial oxidation of methane over SiO₂ and γ-Al₂O₃ supported Rh and Ru catalysts is consistent with the above mechanisms. It is also found that consecutive oxidation of surface CO species is an important pathway of CO₂ formation during the partial oxidation of methane to synthesis gas over Rh/SiO₂ and Ru/γ-Al₂O₃ catalysts.     

ZrOCl_2-H_2SO_4/γ-Al_2O_3催化剂的制备及对1-丁烯齐聚反应的催化性能

以γ-Al_2O_3为载体,负载Zr OCl_2和H_2SO_4制备Zr OCl_2-H_2SO_4/γ-Al_2O_3催化剂,并用于1-丁烯齐聚反应。采用气相色谱在线分析,确定产物组成,考察制备条件对催化剂催化活性的影响,通过1-丁烯转化率和主产物选择性确定适宜的反应条件。结果表明,在Zr OCl_2和H_2SO_4负载质量分数为4.5%和焙烧温度500℃条件下制备的催化剂,在反应温度140℃、1-丁烯液时空速2 h-1和N2分压1.4 MPa条件下,表现出较好的催化活性,1-丁烯转化率96.77%,产物以二聚体(C8)为主,选择性85.99%。该催化剂失活后容易再生,且催化活性良好,1-丁烯转化率92.73%,C8选择性86.73%。     

水热处理对氧化铝载体物化性质及丙烷脱氢性能的影响

采用水热处理对γ-Al2O3载体改性,并进行XRD、N2物理吸附-脱附、热重、NH3-TPD及H2-TPR表征。结果表明,γ-Al2O3经过"再水合-焙烧"过程,晶型变好,表面总酸量降低,Pt-Al2O3相互作用增加,提高了Pt Sn K/Al2O3催化剂的丙烷脱氢转化率、选择性及稳定性。其中,140℃处理4 h时,氧化铝负载的Pt Sn K催化剂表现出最优的丙烷脱氢性能,100 h内平均转化率为33.6%,平均选择性97.3%,失活参数为15.9%。     

Pd-M(Ce、Ca、Fe)/γ-Al_2O_3催化2,5-二氢呋喃加氢性能

通过分步浸渍法制备了Pd含量为0.3%,M含量为3.0%的Pd-M(M=Ce、Ca、Fe)/γ-Al_2O_3催化剂,采用XRD、N_2物理吸附-脱附、H_2-TPR、H_2-TPD和Py-IR等对催化剂进行表征,并研究了助剂对Pd/γ-Al_2O_3催化剂催化2,5-二氢呋喃加氢性能的影响。结果表明,在Pd/γ-Al_2O_3催化剂中引入助剂,降低了Pd与金属相互作用,同时减少了表面暴露L酸位点;促进了2,5-二氢呋喃加氢转化为四氢呋喃,抑制了异构化产物2,3-二氢呋喃的产生。特别是Fe的引入,与Pd之间的协同作用,使CC双键在Pd表面吸附增强,2,5-二氢呋喃转化率大幅提高。该催化剂在反应温度30℃,氢压0.5 MPa和反应时间1 h的加氢条件下,2,5-二氢呋喃转化率达到94.25%,目标产物四氢呋喃选择性达到99.97%。     

Thermodynamic analysis of steam reforming of glycerol for hydrogen production at atmospheric pressure

Thermodynamic chemical equilibrium analysis of steam reforming of glycerol(SRG)for selective hydrogen production was performed based on the Gibbs free energy minimisation method.The ideal SRG reaction(C₃H₈O₃+3H₂O→3CO₂+7H₂)and a comprehensive set of side reactions during SRG are considered for the formation of a wide range of products.Specifically,this work focused on the analysis of formation of H₂,CO₂,CO and CH4 in the gas phase and determination of the carbon free region in SRG under the conditions at atmospheric pressure,600 K–1100 K and 1.013×10⁵–1.013×10⁶ Pa with the steam-to-glycerol feed ratios(SGFR)of 1:5–10.The reaction conditions which favoured SRG for H₂ production with minimum coke formation were identifies as:atmospheric pressure,temperatures of 900 K–1050 K and SGFR of 10:1.The influence of using the inert carrier gas(i.e.,N₂)in SRG was studied as well at atmospheric pressure.Although the presence of N₂ in the stream decreased the partial pressure of reactants,it was beneficial to improve the equilibrium yield of H₂.Under both conditions of SRG(with/without inert gas),the CH4 production is minimised,and carbon formation was thermodynamically unfavoured at steam rich conditions of SGFR>5:1.     

Interactions NO—CO and O2—NO—CO on CuCo2O4/γ-Al2O3 and on γ-Al2O3- and CuCo2O4/γ-Al2O3-supported Pt, Rh and Pt—Rh catalysts, a transient response study

The interactions NO—CO and O₂—NO—CO have been studied onCuCo₂O₄γ-Al₂O₃ and on γ-Al₂O₃- and CuCo₂O₄γ-Al₂O₃-supported Pt, Rh and Pt—Rh catalysts. The deposition of noble metals (Pt, Rh and Pt—Rh) on CuCo₂O₄γ-Al₂O₃ instead of γ-Al₂O₃ is beneficial in: lowering the temperature at which maximum N₂O is formed and decreasing the maximum N₂O concentration attained; lowering the onset temperature of NO to N₂ reduction, and increasing the N₂ selectivity; preserving the activity towards NO to N₂ reduction on a higher level following the concentration step NO + COO₂+ NO + CO and changing the conditions from stoichiometric to oxidizing (50% excess of oxidants). The reason for this behaviour of the CuCo₂O₄γ-Al₂O₃-based noble metal catalysts is the formation (reversible) of a reduced surface layer on the CuCo₂O₄ supported spinel under the conditions of a stoichiometric NO + CO mixture.     

高Al_(13)含量聚合氯化铝制备γ-Al_2O_3及表征(英文)

In this paper a polyaluminum chloride solution with high Al13 content was prepared and used as raw material for preparation ofγ-Al2O3.The texture and crystalline phase of the prepared alumina samples were characterized by energy dispersive X-ray spectroscopy(EDX) ,X-ray diffraction,transmission electron microscope(TEM) and nuclear magnetic resonance(NMR) analyses.The effects of alkaline solution and calcination temperature were investigated.The results showed that alkaline solution including NH3·H2O and NaOH had little effect on the alumina sample formation.The impurities of NH4Cl and NaCl in solution can be removed through repeated washing by EDX analysis.Calcination temperature had a significant effect on alumina crystal phase.The alumina sample can transform completely toγ-Al2O3 in the subsequent heating from 600°C to 800°C.It is very interesting that Al13 can be existed inγ-Al2O3 phase even after calcinations.The results indicate that polyaluminum chloride with high Al13 content is an effective material to prepareγ-Al2O3.