钯复合膜的制备及其在氢气氮气分离中的应用

Thin palladium composite membranes were prepared by modified electroless plating method on a-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over mtrogen. The hydrogen permeance of the corresponding membrane was ashigh as 2.45×10^-6mol·m^-2·s^-1.Pa^-1 and H2/N2 selectivityover700 at 623K and a pressure difference of 0.1MPa. The-main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.     

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.     

Fabrication of Pd-Nb bimetallic doped organosilica membranes by different metal doping routes for H_/CO_2 separation

Monometallic doping has proved its superiority in improving either permselectivity or H_2 permeability of organosilica membranes for H_2/CO_2 separation, but it is still challenging to break the trade-off effect. Herein,we report a series of Pd-Nb bimetallic doped 1,2-bis(triethoxysilyl)ethane(Pd-Nb-BTESE, PNB) membranes with different metal doping routes for simultaneously improving H_2 permeance and H_2/CO_2 permselectivity by the synergetic effects of Pd and Nb. The doped Pd can exist in the BTESE network as nanoparticles while the doped Nb is incorporated into BTESE network forming Nb-O-Si covalent bonds. The metal doping routes significantly influence the microstructure of PNB networks and gas separation performance of the PNB membranes.We found that the PNB membrane with Pd doping priority(PNB-Pd) exhibited the highest surface area and pore volume, comparing with Nb doping priority(PNB-Nb) or Pd-Nb simultaneous doping(PNB-PdNb). The PNB-Pd membrane could not only exhibit an excellent H_2 permeance of ～10~(-6) mol·m~(-2)·s~(-1)·Pa~(-1) but also a high H_2/CO_2 permselectivity of 17.2. Our findings may provide novel insights into preparation of bimetallic doped organosilica membranes with excellent H_2/CO_2 separation performance.     

Crosslinked P84 copolyimide/MXene mixed matrix membrane with excellent solvent resistance and permselectivity

MXene is a novel 2D lamellar material with excellent hydrophilicity and permselectivity. MXene was introduced in the P84 polymer matrix and the matrix was crosslinked with triethylenetetramine(TETA) to improve the permselectivity and solvent resistance of the polyimide membrane. The membrane was characterized with SEM, AFM and ATR-FTIR, and effects of MXene content on the membrane morphology and separation performance are investigated. The membrane prepared with 18% P84 and 1% MXene shows high rejection(100%) to gentian violet(408) and high flux(268 L·m~(-2)·h~(-1)) at 0.1 MPa and ambient temperature. MXene endows the membrane with much water channel and denser functional layer which improves the membrane performance obviously. The membrane shows excellent solvent resistance to dimethylformamide(DMF), acetone and methanol after crosslinking with TETA during the 18 days of immersion.     

Permeation properties of CO2and CH4in asymmetric polyethersulfone/polyesterurethane and polyethersulfone/polyetherurethane blend membranes

The transport performances of carbon dioxide and methane were studied in polyethersulfone,polyethersulfone/polyeterurethane (PES-ETPU) and polyethersulfone/polyestherurethane (PES-ESPU) blend membranes separately with different compositions.The variations in the structural characteristics of PES membrane after incorporation of ESPU and ETPU were investigated by different techniques.Additionally,the effect of pressure and composition on the permeance of CO2,CH4and ideal selectivity of CO2/CH4were checked on the membranes. The results revealed that the morphology of the blend membranes was affected by two opposite factors:thermo-dynamic enhancement and kinetic hindrance.The membranes with denser sponge layers were formed at lower ratio of PU/PES,while more porous structure with enlarged macrovoids membranes were observed at higher PU content.The results indicated that adding PU to PES membrane,caused permeance improvement of the gases with nearly no change and/or reduction in ideal selectivity of CO2/CH4.Moreover,PES-ETPU membranes showed higher permeability and less CO2/CH4selectivity in comparison with PES-ESPU samples. For PES-ESPU membrane containing 1.5% ESPU,CO2permeance at 10 bar was improved up to 20% with almost no change in CO2/CH4selectivity with respect to PES.Finally,response surface methodology was used to evaluate the effects of the operating parameters on the permeance and ideal selectivity.     

Effect of sol size on nanofiltration performance of a sol-gel derived microporous zirconia membrane

This paper reports the effect of sol size on nanofiltration performances of sol–gel derived microporous zirconia membranes. Microstructure, pure water flux, molecular weight cut-off (MWCO) and salt retention of zirconia membranes derived from zirconia sols with different sizes were characterized. Thermal evolution, phase compo-sition, microstructure and chemical stability of unsupported zirconia membranes (powder) were determined by thermogravimetric and differential thermal analysis, X-ray diffraction, nitrogen adsorption–desorption and static solubility measurements. Results show that nanofiltration performance of zirconia membranes is highly depen-dent on sol size. The sol with an average size of 3.8 nm, which is smaller than the pore size of theγ-Al2O3 support (pore size:5–6 nm), forms a discontinuous zirconia separation layer because of excessive penetration of sol into the support. This zirconia membrane displays a MWCO value towards polyethylene glycol higher than 4000 Da. A smooth and defect-free zirconia membrane with a MWCO value of 1195 Da (pore size:1.75 nm) and relative high retention rates towards MgCl2 (76%) and CaCl2 (64%) was successfully fabricated by dip-coating the sol with an appropriate size of 8.6 nm. Zirconia sol with an average size of 12 nm exhibits colloidal nature and forms a zirconia membrane with a MWCO value of 2332 Da (pore size:2.47 nm). This promising microporous zirconia membrane presents sufficiently high chemical stability in a wide pH range of 1–12.     

Gradient nanoporous phenolics as substrates for high-flux nanofiltration membranes by layer-by-layer assembly of polyelectrolytes

Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m~(-2)?h~(-1)?MPa~(-1), which is ～2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.     

Energy and economic analysis of a hydrogen and ammonia co-generation system based on double chemical looping

In this work, a model of hydrogen production by double chemical looping is introduced. The efficiency benefit obtained was investigated. The chemical looping hydrogen generation unit is connected in series to the downstream of a chemical looping gasification unit as an additional system for 100 MW·h coal gasification, with the function of supplementary combustion to produce hydrogen. Using Aspen Plus software for process simulation, the production of H_2 and N_2 in the series system is higher than that in the independent Chemical looping gasification and Chemical looping hydrogen generation systems, and the production of hydrogen is approximately 25.63% and 12.90% higher, respectively; The study found that when the gasification temperature is 900 °C, steam-carbon ratio is 0.84 and oxygen-carbon ratio is 1.5,the hydrogen production rate of the system was the maximum. At the same time, through heat exchange between logistics, high-pressure steam at 8.010×10~4 kg·h~(-1) and medium-pressure steam at 1.101×10~4 kg·h~(-1) are generated, and utility consumption is reduced by 61.58%, with utility costs decreasing by 48.69%. An economic estimation study found that the production cost of ammonia is 108.66 USD·(t NH_3)~(-1). Finally, cost of equipment is the main factors influencing ammonia production cost were proposed by sensitivity analysis.     

Synthesis of Zirconia Powder in Zirconia Aqueous Sol

Spherical zirconia particles formed by coagulation of colloidal particles in zirconia aqueous sol followed by calcination.The zirconia sol was prepared from zirconium oxychloride aqueous solution by adjusting its pH value.The coag-ulation resulted from addition of preopanol in the sol the coagulation mechanism was discussed based on collicd theory.     

用于CO2捕集的新型酒石酸钠交联海藻酸钠膜的制备（英文）

The membrane-based CO2 separation process has an advantage compared to traditional CO2 separation technologies. The membrane is the key of the membrane separation process. In this paper, preparation, characteriza-tion and laboratory testing of the membrane, which was prepared from sodium alginate, hydrogen bond cross-linked with sodium tartrate and used for CO2/N2 separation, were reported. The resistance to SO2 of the membrane was also investigated. The experimental results demonstrate that the membrane possesses a high resistance to SO2. Finally, based on experimental results, the economic feasibility of the membrane used for CO2/N2 separation was evaluated, indicating the two-stage membrane process can compete with the traditional chemical absorption method.     

Preparation,Performance and Slag Resistant Mechanism of Low Thermal Conductivity Microporous Corundum

The microporous corundum material was prepared using alumina micro-powder as the main raw material,alumina sol and starch as binders by a wet process,achieving the bulk density of 3. 05 g·cm~(-3),the apparent porosity of 9. 1%,the closed porosity of 12. 3%,the median pore diameter of 0. 43 μm,and the thermal conductivity of 6. 5 W·m~(-1)·K~(-1)at 800 ℃ which is41. 6% lower than that of common corundum. The slag resistance of the microporous corundum material was studied by immersion and compared with that of the common corundum aggregate, and the slag resistant mechanism of microporous corundum material was revealed. The results show that the slag resistance of the microporous corundum material is superior to that of the common corundum aggregate,the SEM and EDX show that on the reaction interface between microporous corundum and molten slag,a continuous isolation layer with a large quantity of CA_2 and CA_6columnar crystals is formed; while the common corundum aggregate reacts with the molten slag interface to form a discontinuous isolation layer of columnar crystals,through which a lot of molten slag corrodes or permeates into the aggregate. The mechanism is mainly that the microporous structure is more advantageous to nucleation and growth of CA_2 and CA_6 columnar crystals; in the reaction with the aggregate,the molten slag gets saturated and the critical solution thickness of the microporous corundum and the common corundum is 0. 16 μm and 0. 34 μm,respectively,this is caused by the smaller microporous corundum aggregate pores; and the smaller pores also increase the second phase ripening rate of microporous corundum,which is 9. 7 times of that of the common corundum.     

壳聚糖亲和膜脱除蛋白质溶液中的内毒素

Affinity membrane was prepared with chitosan immobilized on the hydrophile- modified poly(vinylidene fluoride) (PVDF) membrane. Fourier transform infrared spectroscopy (FTIR) analysis indicated that the contents of-NH2 and -OH groups increased and fluoride decreased on the membrane surface after modification. Using this kind of affinity membrane, the effects of operation parameters such as pH, ionic strength and flow rate, on the amount of endotoxin removed were investigated. The results showed that the equilibrium adsorption capacity and the dissociation constant of the affinity membrane to endotoxin were 21.4 EU·mg-1 membrane and 0.50 EU·ml-1,respectively, at pH 7.0 and ionic strength 0.2 mol·L-1. Adsorption appeared to follow a typical Langmuir adsorption isotherm. At pH 5.0, ionic strength of 0.2 mol·L-1, the removal rate of endotoxin from BSA solution with the chitosan affinity membrane was up to 88.6% (11.50 EU·mg-1 membrane), and the recovery of BSA was 93.4% (0.187 mg·mg-1 membrane), while at pH 11.0, ionic strength of 0.2 mol·L-1, the removal rate of endotoxin from lysozyme solution was 72.4% (9.92 EU·mg- 1 membrane), and the recovery of lysozyme was 92.3% (0.104 mg·mg- 1 membrane).     

Preparation of hydrophobic flat sheet membranes from PVDF-HFP copolymer for enhancing the oxygen permeance in nitrogen/oxygen gas mixture

In this study, poly(vinilydene fluoride-co-hexafluoropropylene)(PVDF-HFP) was used for preparation of hydrophobic membranes using non-solvent induced phase inversion(NIPS) technique. PVDF-HFP copolymer with concentrations of 10 wt% and 12 wt% was prepared to investigate the effect of polymer concentration on pore structure,morphology, hydrophobicity and performance of prepared membranes. Besides, the use of two coagulation baths with the effects of parameters such as coagulant time, polymer type and concentration, and the amount of nonsolvent were studied. The performance of prepared membranes was evaluated based on the permeability and selectivity of oxygen and nitrogen from a gas mixture of nitrogen/oxygen under operating conditions of feed flow rate(1–5 L·min~(-1)), inlet pressure to membrane module(0.1–0.5 MPa) and temperatures between 25 and 45 °C. The results showed that the use of two coagulation baths with different compositions of distillated water and isopropanol,coagulant time, polymer type and concentration, and the amount of non-solvent additive have the most effect on pore structure, morphology, thickness, roughness and crystallinity of fabricated membranes. Porosity ranges for the three fabricated membranes were determined, where the maximum porosity was 73.889% and the minimum value was 56.837%. Also, the maximum and minimum average thicknesses of membrane were 320.85 μm and115 μm. Besides, the values of 4.7504 × 10~(-7) mol· m~(-2)· s~(-1)· Pa~(-1), 0.525 and 902.126 nm were achieved for maximum oxygen permeance, O_2/N_2 selectivity and roughness, respectively.     

Performance of Ni/Nano-ZrO2catalysts for CO preferential methanation简

Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The cata- lysts were characterized by Brunauer-Emmett-Teller （BET）, transmission electron microscope （TEM）, X-ray dif- fraction （XRD） and temperature-programmed reduction （TPR）. The results showed that the as-synthesized Ni/nano-ZrO2 catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zir- conia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5% （by mass） Ni/ZrO2 catalyst calcinated at 500℃ was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99% conversion in the CO/CO2 competitive methanation system over the temperature range of 260-280℃, while keeping the CO2 conversion relatively low.     

An Experimental Investigation of Hydrogen Production from Biomass

In gaseous products of biomass steam gasification, there exist a lot of CO, CH4 and other hydrocarbons that can be converted to hydrogen through steam reforming reactions. There exists potential hydrogen production from the raw gas of biomass steam gasification. In the present work, the characteristics of hydrogen production from biomass steam gasification were investigated in a small-scale fluidized bed. In these experiments, the gasifying agent (air) was supplied into the reactor from the bottom of the reactor and the steam was added into the reactor above biomass feeding location. The effects of reaction temperature, steam to biomass ratio, equivalence ratio (ER) and biomass particle size on hydrogen yield and hydrogen yield potential were investigated. The experimental results showed that higher reactor temperature, proper ER, proper steam to biomass ratio and smaller biomass particle size will contribute to more hydrogen and potential hydrogen yield.     

以正硅酸乙酯和1,2-二(三乙氧基硅基)乙烷为前驱体制备微孔SiO2复合膜及其气体分离性能

This paper reports on ¬¬¬a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate (TEOS) and a bridged silsesquioxane [1, 2-bis(triethoxysilyl)ethane, BTESE] as precursors. A stable nano-sized composite silica sol with a mean volume size of ~5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al2O3 and mesoporous γ-Al2O3 intermediate layer by using dip-coating ap-proach, followed by calcination under pure nitrogen atmosphere. The composite silica membranes exhibit molecular sieve properties for small gases like H2, CO2, O2, N2, CH4 and SF6 with hydrogen permeances in the range of (1-4)107 mol•m2•s1•Pa1 (measured at 200 C, 3.0×105 Pa). With respect to the membrane calcined at 500 C, it is found that the permselectivities of H2 (0.289 nm) with respect to N2 (0.365 nm), CH4 (0.384 nm) and SF6 (0.55 nm) are 22.9, 42 and >1000, respectively, which are all much higher than the corresponding Knudsen values (H2/N2 3.7, H2/CH4 2.8, and H2/SF6 8.5).     

Kinetic study on reactive extraction of phenylalanine enantiomers with BINAP-copper complexes

Enantioselective liquid–liquid extraction has attracted considerable attention for its potential use in large-scale production. Kinetic data are needed for the reliable scale-up of the process. This paper reports the kinetic study of reactive extraction of phenylalanine (Phe) enantiomers with BINAP–copper complex (BINAP–Cu) as a chiral selector. The theory of extraction accompanied by a chemical reaction was applied. The effects of agitation speed, interfacial area, pH value of aqueous phase, initial concentration of Phe enan-tiomers and initial concentration of BINAP–Cu on the specific rate of extraction were investigated. The for-ward rate constants of the reactions in the reactive extraction process are 7.93 × 10?5 m5/2·mol?1/2·s?1 for D-Phe and 1.29 × 10?4 m5/2·mol?1/2·s?1 for L-Phe.     

一种引入CO2选择性吸附硅纳米颗粒提高固定载体膜性能的方法（英文）

Fixed carrier membrane exhibits attractive CO2 permeance and selectivity due to its transport mecha-nism of reaction selectivity (facilitated transport). However, its performance needs improvement to meet cost targets for CO2 capture. This study attempts to develop membranes with multiple permselective mechanisms in order to enhance CO2 separation performance of fixed carrier membrane. In this study, a novel membrane with multiple permselective mechanisms of solubility selectivity and reaction selectivity was developed by incorporating CO2-selective adsorptive silica nanoparticles in situ into the tertiary amine containing polyamide membrane formed by interfacial polymerization (IP). Various techniques were employed to characterize the polyamide and polyam-ide-silica composite membranes. The TGA result shows that nanocomposite membranes exhibit superior thermal stability than pure polyamide membranes. In addition, gas permeation experiments show that both nanocomposite membranes have larger CO2 permeance than pure polyamide membranes. The enhanced CO2/N2 separation per-formance for nanocomposite membranes is mainly due to the thin film thickness, and multiple permselective mechanisms of solubility selectivity and reaction selectivity.     

CO2通过合成聚合物膜的促进传递

Two kinds of fixed carrier membrane materials containing secondary amine and carboxyl groups whichcan be used as carriers of CO2 were prepared. One was poly(N-vinyl-γ-sodium aminobutyrate)(PVSA), whichwas obtained through the hydrolysis of polyvinylpyrrolidone (PVP) synthesized with N-vinylpyrrolidone(NVP) byradical polymerization. The other was poly(N-vinyl-γ-sodium aminobutyrate-co-sodium acrylate)(VSA-SA), whichwas obtained through the hydrolysis of copolymer of N-vinylpyrrolidone and acrylamide(AAm) (NVP-AAm). Thecomposite membranes were developed with PVSA or VSA-SA as active layer and polysulfone (PS) as supportmembranes. The permeation rates of pure CO2 and CH4 gas as well as binary mixtures of CO2/CH4 throughthe composite membranes were measured. The results show that the composite membranes present better CO2permeation rates than other fixed carrier membranes do reported in literature. For example, at 26℃, 1330 Pa of CO2pressure, the PVSA/PS composite membrane displays a CO2 permeation rate of 5.95 × 10-7 cm3.cm-2.s-1.pa-1with CO2/CH4 ideal separation factor of 212.1. At 20℃, 6400Pa of CO2 pressure, the VSA-SA/PS compositemembrane displays a CO2 permeation rate of 4.24 × 10-8 cm3@cm-2.s-1.Pa-1 with CO2/CH4 ideal separationfactor of 429.7. The results with the gas mixtures are not as good as those obtained with pure gas because ofthe coupling effects between CO2 and CH4. The heat cross-linked membrane shows good separation factor due todensification of the polymer.     

Electrochemical analysis and convection-enhanced mass transfer synergistic effect of MnOx/Ti membrane electrode for alcohol oxidation

The different electrocatalytic reactors could be constructed for the electrocatalytic oxidation of 2,2,3,3-tetrafluoro-1-propanol(TFP) with two typical MnO_x/Ti electrodes, i.e.the electrocatalytic membrane reactor(ECMR) with the Ti membrane electrode and the electrocatalytic reactor(ECR) with the traditional Ti plate electrode.For the electro-oxidation of TFP, the conversion with membrane electrode(70.1%) in the ECMR was 3.3 and 1.7 times higher than that of the membrane electrode without permeate flow(40.8%) in the ECMR and the plate electrode(21.5%) in the ECR, respectively.Obviously, the pore structure of membrane and convection-enhanced mass transfer in the ECMR dramatically improved the catalytic activity towards the electro-oxidation of TFP.The specific surface area of porous electrode was 2.22 m~2·g~(-1).The surface area of plate electrode was 2.26 cm~2(1.13 cm~2× 2).In addition, the electrochemical results showed that the mass diffusion coefficient of the MnO_x/Ti membrane electrode(1.80 × 10~(-6) cm~2·s~(-1)) could be increased to 6.87 × 10~(-6) cm~2·s~(-1) at the certain flow rate with pump, confirming the lower resistance of mass transfer due to the convection-enhanced mass transfer during the operation of the ECMR.Hence, the porous structure and convection-enhanced mass transfer would improve the electrochemical property of the membrane electrode and the catalytic performance of the ECMR,which could give guideline for the design and application of the porous electrode and electrochemical reactor.