高渗透性YSZ中空纤维陶瓷微滤膜的制备

采用相转化和高温烧结相结合的方法,并在纺丝过程分别以水和乙醇作为芯液和外凝固浴制备了多孔氧化钇稳定氧化锆（YSZ）中空纤维陶瓷膜,对制备的中空纤维膜微观结构、孔径分布和孔隙率、纯水通量和氮气渗透性等进行了表征。结果表明：制备的YSZ中空纤维膜为多孔非对称结构,由外部薄的海绵状多孔皮层和内部大的指孔层构成。在1350℃保温4h烧成制备的YSZ中空纤维膜表现出高渗透性,在0.10MPa压差下的纯水和氮气渗透性分别达到43.0m^3/（m^2·h.MPa）和8345.7m^3/（m^2·h·MPa）。     

聚醚砜分子量对相转化法YSZ中空纤维陶瓷膜结构与性能的影响

采用不同分子量聚醚砜(PES)作为聚合物结合剂,通过相转化法和高温烧结制备了非对称结构YSZ中空纤维陶瓷膜。研究了不同分子量聚醚砜制备的铸膜浆料粘度变化对相转化过程及膜的微观结构与孔隙率和孔径、纯水和氮气渗透通量及抗弯强度等性能的影响。结果表明,采用分子量较小的PES制备的中空纤维膜由内侧大指孔结构和外侧小指孔结构构成。随着PES分子量和铸膜浆料粘度提高,外侧指孔长大而内侧指孔减小,且出现明显的中间海绵层。随着浆料粘度提高,膜孔隙率明显下降。采用PES E3010作为聚合物原料时,制备的YSZ中空纤维膜具有最大的外表皮层分离孔径,表现出最高的渗透性能和抗弯强度,在1400℃保温3 h烧结时,膜纯水通量和抗弯强度分别可达到9.35 m~3/(m~2·h·MPa)和113.9 MPa。     

一步成型制备非对称多孔YSZ中空纤维陶瓷膜

采用有机相转化与固态粒子烧结法相结合,通过一步成型制备了非对称多孔氧化钇稳定氧化锆(YSZ)中空纤维陶瓷膜。SEM微观结构分析表明,制备的YSZ中空纤维陶瓷膜为非对称多孔结构,中间为多孔海绵状结构,内外两侧为指孔结构,且内外表层平均孔径分别为0.43μm和0.18μm。YSZ中空纤维陶瓷膜抗弯强度和纯净水通量分别为210.5MPa和4.02m~3·m~(-2)·h~(-1)·bar~(-1)。     

低成本大孔陶瓷膜支撑体的制备与表征(英文)

以高岭土和白云石为主要原料,通过反应烧结法制备低成本大孔陶瓷膜支撑体,对制备的支撑体进行了结构和性能表征.结果表明:在高岭土中引入质量分数为20%的白云石,可显著抑制高岭土的高温烧结;加入白云石后制备的支撑体在1 150~1 300℃保温1h后,主晶相为莫来石、堇青石和钙长石,平均孔径和抗弯强度随烧成温度升高而增大,而水通量和孔隙率降低;加入20%白云石并在1 250℃保温1 h制各的大孔支撑体的孔隙率和平均孔径分别为44.6%和4.7μm,抗弯强度和纯净水通量分别达到47.6MPa和10.76m3/(m2·h·bar).     

浸渍-裂解法增强碳化硅-堇青石支撑体强度

陶瓷过滤膜在高温烟气分离领域有着重要的应用,其关键问题在于提高陶瓷支撑体在热冲击和酸性条件下的热稳定性。本研究采用SiC-堇青石作为陶瓷支撑体材料,利用浸渍-裂解法制备得到SiC-堇青石陶瓷支撑体。研究结果表明,通过浸渍-裂解法有效地消除了支撑体的弱结合区域,同时前驱体原位形成修补相,共同提高了体系的强度。最终制备的SiC-堇青石支撑体的平均孔径为6.2μm,开孔孔隙率为36.4%,抗弯强度49.2MPa,氮气通量为1.2×10~4 m~3/(m~2hbar),经过30次高温循环后抗弯强度保持约42 MPa,表现出优异的热稳定性。     

硅藻土/α-Al_2O_3中空纤维膜的制备与表征

文中采用相转化烧结的方法制备了硅藻土/α-Al_2O_3中空纤维膜,研究了硅藻土百分含量和烧结温度对制备的中空纤维膜性能的影响,该中空纤维膜具有较高的纯水通量和较高的机械强度,在硅藻土百分含量为10%,烧结温度为1 250℃,烧结时间为2 h的条件下,制备的硅藻土/α-Al_2O_3中空纤维膜抗弯强度为15.83 MPa,在操作压力为0.15 MPa时,纯水通量为3 227.18 L/(m~2·h),平均孔径范围为0.27～0.40μm,泡压范围为0.22～0.43 MPa。在大肠杆菌的去除试验中,去除率达到99.99%以上,能够有效去除饮用水中的大肠杆菌,可用于饮用水的微滤除菌应用。     

镍渣制备多孔堇青石陶瓷的研究

以镍渣、Al_2O_3和SiO_2为原料,按偏镁铝方案确定堇青石的组成,无需添加额外的烧结助剂和造孔剂,成功制备出多孔堇青石陶瓷。测定了试样的显气孔率、抗弯强度和热膨胀系数,用XRD分析了试样在烧结过程中的物相变化,并用SEM观察其断面的显微结构。结果表明:在1200~1380℃保温4 h,制备的多孔陶瓷的显气孔率为38.13~31.39%,抗弯强度为25.53~32.54 MPa,热膨胀系数为3.17×10~(-6)~1.43×10~(-6)/℃,且其主晶相为堇青石。SEM图谱显示多孔堇青石陶瓷中堇青石晶体呈六方棱柱状,还存在大量孔洞。     

二氧化钛超滤膜的制备及其渗透性能

用溶胶-凝胶工艺在涂覆两层ZrO2中间层的堇青石多孔陶瓷管上制备TiO2超滤膜。通过X射线衍射、扫描电子显微镜、孔隙度分析仪及原子力显微镜分析膜材料的形貌、厚度和孔隙率与结构。结果表明:所制备的各层膜结构完整、厚度合适且孔径分布均匀呈阶梯式递减;主晶相为锐钛矿的TiO2超滤膜,厚度为50nm,最可几孔径为15nm左右。对薄膜的渗透性能测试结果表明:所制样品对纯水的平均渗透率为131.6L/(h·m2·MPa),0.2MPa工作压力下对分子量580000右旋糖苷的截留率为94.76%。     

聚酰亚胺中空纤维气体分离膜的物理老化现象

以聚酰亚胺6FDA-mPDA为原料制备了单层非对称中空纤维膜,以聚酰亚胺Matrimid5218为分离层材料制备了双层非对称中空纤维膜,膜的致密层厚度为0.09~0.21μm。测试了中空纤维膜的O2、N2、CH4和CO2等气体渗透性能随时间的变化,研究了中空纤维膜物理老化现象。结果表明,随着老化的进行,气体渗透速率逐渐减小,分离系数逐渐变大,直至平衡。以自由体积扩散机理为基础,针对非对称中空纤维膜具有超薄皮层的特点,建立描述物理老化过程的数学模型。结果表明,该模型与实验结果相吻合,表明自由体积扩散机理可用来描述具有超薄皮层的中空纤维膜的物理老化现象。     

湿法纺丝工艺制备Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3–δ)中空纤维陶瓷透氧膜及其改性研究

采用固相反应法合成Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3–δ)(BSCF)粉,并以其为原料,采用湿法纺丝工艺及烧结处理制备出外径为3 mm、壁厚为400μm的BSCF中空纤维膜,通过涂覆法,在中空纤维膜的外表面负载BSCF多孔层,以进一步改善其透氧性能。利用X射线衍射对BSCF粉末与中空纤维膜的相组成进行分析,采用扫描电子显微镜对中空纤维膜的微观组织进行观测,对修饰后BSCF膜的透氧性能进行测试。结果表明:采用固相反应法可制备出具有单一钙钛矿相的BSCF粉体,湿法纺丝所制备的BSCF中空纤维膜具有非对称结构;在空气/真空梯度下,未经表面修饰的BSCF膜在700和900℃时的透氧速率分别为0.382和1.284 m L/(cm2·min)。表面负载Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3–δ)多孔层后,其700和900℃的透氧速率分别增加到1.250和2.426 m L/(cm2·min)。表面负载使BSCF的中空纤维透氧膜的透氧表观活化能从49.23降低至24.74 k J/mol。     

Preparation and characterization of braided tube reinforced polyacrylonitrile hollow fiber membranes

Polyacrylonitrile (PAN) and polyester (PET) braided hollow tube that used as a special reinforcement are braided from their filaments via two‐dimensional weaving techniques. PAN braided tube reinforced homogeneous PAN hollow fiber membranes and PET braided tube reinforced heterogeneous PAN hollow fiber membranes are prepared by concentric circles squeezed‐coated spinning method. As for PAN hollow fiber membrane, the effects of PAN concentration on the performance of the prepared hollow fiber membranes are investigated in terms of pure water flux, protein rejection, mechanical strength, and morphology observations by a scanning electron microscope (SEM). The interfacial bonding state of the braided tube reinforced PAN hollow fiber membranes is studied by constant speed stretching method. Results show that the breaking strength of two‐dimensional braided tube reinforced PAN hollow fiber membranes is higher than 80 MPa. The structure of separation surface is similar to the structure of an asymmetric membrane. With the increase of polymer concentration, the membrane flux decreases while the retention rate of BSA increase. The membrane porosity and maximum pore size have the same decreasing tendency as the increase of PAN concentration. The results also show that the interfacial bonding state of the PAN two‐dimensional braided tube reinforced homogeneous PAN hollow fiber membranes is better than that of the PET two‐dimensional braided tube reinforced heterogeneous PAN hollow fiber membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41795.     

Effect of stretching on continuous oil/water separation performance of polypropylene hollow fiber membrane

In this work, polypropylene (PP) hollow fiber membranes were fabricated by thermal-induced phase separation method. The influence of cold-stretched and hot-stretched treatment on the morphology and permeability of the PP hollow fiber membranes was investigated. The results showed that there were cracks and crystalline particulate structures on the outer and inner surfaces of the stretched PP hollow fiber membranes, which were not isolated but linked together through fiber-like connections. Compared to the original PP hollow fiber membrane, the mean pore sizes, the porosities, the hydrophobicity and water entry pressure of the stretched PP hollow fiber membranes improved significantly. When applied in conjunction with a vacuum system, the PP hollow fiber membranes could continuously remove oils from water surface, and separate surfactant-free and surfactant-stabilized water-in-oil emulsions, as well. The initial kerosene fluxes of the hot-stretched PP hollow fiber membrane were higher than that of the membranes prepared from original PP hollow fibers or cold-stretched PP hollow fibers. The permeate fluxes of the hot-stretched PP hollow fiber membrane for all different emulsion separations were higher than those of the original PP hollow fiber membrane. There could be seen no emulsion droplet in the optical micrographs after separation, indicating that the water-in-oil emulsions were effectively separated in one-step method.     

Effect of TEP content in cooling bath on porous structure,crystalline and mechanical properties of PVDF hollow fiber membranes

Poly (vinylidene fluoride) (PVDF) hollow fiber membranes were prepared by adding triethyl phosphate (TEP) to the cooling water bath in a modified thermally induced phase separation process. The effect of TEP content in the cooling bath on the porous structure, crystallinity, thermal and mechanical properties of PVDF hollow fiber membranes was investigated. The melting temperature and crystallinity of the membranes were determined using differential scanning calorimetry. The crystalline and cross‐section morphology of the hollow fiber membranes were investigated using wide angle X‐ray diffraction and scanning electron microscopy. The resulting membrane exhibited a nearly symmetric structure. The results showed that the TEP content in the cooling bath had a crucial role on the membrane formation, which was also confirmed from the morphology and mechanical properties of the hollow fibers. The porosity, average pore size, crystallinity, Young's modulus, max stress, and elongation at breakage of the hollow fiber membranes can be related to the amount of TEP in the cooling bath. Better pore connectivity was obtained in hollow fiber membranes when the weight ratio of TEP to water was 40:60. POLYM. ENG. SCI., 54:2207–2214, 2014. © 2013 Society of Plastics Engineers     

Preparation of a heterogeneous hollow‐fiber affinity membrane modified with a mercapto chelating resin

A high‐quality, heterogeneous hollow‐fiber affinity membranes modified with mercapto was prepared through phase separation with blends of a chelating resin and polysulfone as membrane materials, poly(ethylene glycol) as an additive, N,N‐dimethylacetamide as a solvent, and water as an extraction solvent. The effects of the blending ratio and chelating resin grain size on the structure of the hollow‐fiber affinity membrane were studied. The effects of the composition of the spin‐cast solution and process parameters of dry–wet spinning on the structure of the heterogeneous hollow‐fiber affinity membrane were investigated. The pore size, porosity, and water flux of the hollow‐fiber affinity membrane all decreased with an increase in the additive content, bore liquid, and dry‐spinning distance. With an increase in the extrusion volume outflow, the external diameter, wall thickness, and porosity of the hollow‐fiber affinity membrane all increased, but the pore size and water flux of the hollow‐fiber affinity membrane decreased. It was also found that the effects of the internal coagulant composition and external coagulant composition on the structure of the heterogeneous hollow‐fiber affinity membrane were different. The experimental results showed that thermal drawing could increase the mechanical properties of the heterogeneous hollow‐fiber affinity membrane and decrease the pore size, porosity, and water flux of the heterogeneous hollow‐fiber affinity membrane, and the thermal treatment could increase the homogeneity and stability of the structure of the heterogeneous hollow‐fiber affinity membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

巡视中空纤维膜的研发和产业进展

介绍了国内外用于人工肾的中空纤维透析膜、用于废水处理的微滤、超滤中空纤维及膜生物反应器（MBR）、用于海水淡化的中空纤维反渗透膜、用于气体分离及有机物代精馏的中空纤维膜、用于双亲和性吸附蛋白质的固定双配合剂多微孔中空纤维膜、用于回收海水资源的微滤和纳滤膜、用于脱氧核糖核酸链（DNA）切片的内含亲水性聚合物的中空纤维膜以及新型电池隔膜.     

Preparation of poly(4‐methyl‐1‐pentene) asymmetric or microporous hollow‐fiber membranes by melt‐spun and cold‐stretch method

Poly(4‐methyl‐1‐pentene) (PMP) hollow fibers were prepared and fabricated into gas separation or microporous membranes by the melt‐spun and cold‐stretched method. PMP resin was melt‐extruded into hollow fibers with cold air as the cooling medium. The effects of take‐up speed and thermotreatment on the mechanical behavior and morphology of the fibers were investigated. Scanning electronic microscope (SEM) photos were used to reveal the geometric structure of the section and surface of the hollow fibers. It was found that the original fiber had an asymmetric structure. A “sandwich” mode was used to describe the formation of this special fine structure. And a series of PMP hollow‐fiber membranes were prepared by subsequent drawing, and it was found that there was a “skin–core” structure on the cross section of these hollow‐fiber membranes. Asymmetric or microporous PMP hollow‐fiber membranes could be obtained by controlling posttreatment conditions. The morphology of these membranes were characterized by SEM, and the gas (oxygen, nitrogen, and carbon dioxide) permeation properties of the membranes was measured. The results indicate that the annealing time of the original fiber and the stretching ratio were the key factors influencing the structure of the resulting membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2131–2141, 2006     

Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes for pervaporation separation of ethanol/water solution

Polysulfone (PSF) hollow fiber membranes were spun by phase‐inversion method from 29 wt % solids of 29 : 65 : 6 PSF/NMP/glycerol and 29 : 64 : 7 PSF/DMAc/glycol using 93.5 : 6.5 NMP/water and 94.5 : 5.5 DMAc/water as bore fluids, respectively, while the external coagulant was water. Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes were prepared after PSF hollow fiber membranes were coated using different PVA aqueous solutions, which were composed of PVA, fatty alcohol polyoxyethylene ether (AEO₉), maleic acid (MAC), and water. Two coating methods (dip coating and vacuum coating) and different heat treatments were discussed. The effects of hollow fiber membrane treatment methods, membrane structures, ethanol solution temperatures, and MAC/PVA ratios on the pervaporation performance of 95 wt % ethanol/water solution were studied. Using the vacuum‐coating method, the suitable MAC/PVA ratio was 0.3 for the preparation of PVA/PSF hollow fiber composite membrane with the sponge‐like membrane structure. Its pervaporation performance was as follows: separation factor (α) was 185 while permeation flux (J) was 30g/m²·h at 50°C. Based on the experimental results, it was found that separation factor (α) of PVA/PSF composite membrane with single finger‐void membrane structure was higher than that with the sponge‐like membrane structure. Therefore, single finger‐void membrane structure as the supported membrane was more suitable than sponge‐like membrane structure for the preparation of PVA/PSF hollow fiber composite membrane. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 247–254, 2005     

Preparation and performance of braid‐reinforced poly(vinyl chloride) hollow fiber membranes

A novel braid‐reinforced (BR) poly(vinyl chloride) (PVC) hollow fiber membrane was fabricated via dry‐wet spinning process. The mixtures of PVC polymer solutions were uniformly coated on the tubular braid which contained polyester (PET) and polyacrylonitrile (PAN) fibers. The influences of braid composition on structure and performance of BR PVC hollow fiber membranes were investigated. The results showed that the prepared BR PVC hollow fiber membranes were composed of two layers which contained separation layer and tubular braid supported layer when the PET and PET/PAN hybrid tubular braids were used as the reinforcement. But the sandwich structure appeared when the PAN tubular braid was used as the reinforcement, which revealed outer separation layer, tubular braid supported layer and the inner polymer layer. The BR PVC hollow fiber membranes that prepared by PET/PAN hybrid tubular braid had favorable interfacial bonding state compared with the membrane prepared by pure PET or PAN tubular braid. The pure water flux of the BR PVC hollow fiber membranes that prepared by the PET/PAN hybrid tubular braid were lower than that prepared by pure PET or PAN tubular braid, but the rejection of Bovine serum albumin was opposite. The tensile strength of prepared BR PVC hollow fiber membrane was higher than 50 MPa. Both of the tensile strength and elongation at break decreased with the increase of the PAN filaments in the PET/PAN hybrid tubular braid. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45068.     

热致相分离法iPP中空纤维微空膜结构与性能--稀释剂的作用

Isotactic polypropylene （iPP） hollow fiber microporous membranes were prepared using thermally induced phase separation （TIPS） method. Di-n-butyl phthalate （DBP）, dioctyl phthalate （DOP）, and the mixed solvent were used as diluents. The effect of α （DOP mass fraction in diluent） on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.     

Mechanical analysis of hollow fiber membrane integrity in water reuse applications

In order to gain insight into membrane fiber failure (i.e., loss of integrity), properties of five hollow fiber membranes and four hollow fiber modules were evaluated. Specifically, membrane material, membrane symmetry, fiber modulus of elasticity, fiber diameter and thickness, module potting technique, module flow pattern (inside-out or outside-in), and coliform breakthrough were investigated. The approach combined evaluation of the above properties with mathematical modeling of structure-fluid interactions to comprehensively evaluate the properties most important for maintaining hollow fiber membrane integrity. Tensile strength testing revealed that the strongest fiber was an asymmetric polyacrylonitrile membrane fiber. The weakest fiber was a symmetric polyethylene membrane fiber. Pilot plant testing on the four membrane modules revealed that membrane symmetry may be a more important factor than potting technique for hollow fiber integrity. Results from the SEM and tensile testing were used as input to a finite element analysis model used to evaluate time-dependent structure-fluid interactions. It was found that additional stresses at the juncture of the potting material and the hollow fiber membranes exist. These stresses likely lead to the formation of fractures.