TiO_2中孔膜的制备及对Ni~(2+)的截留性能

以钛酸四异丙酯为前驱体,通过颗粒溶胶路线制备出平均粒径为41nm的TiO2溶胶,并以此溶胶制备出稳定的制膜液。采用浸浆法,经过一次涂膜和在400～600℃烧成,在平均孔径约为70nm的片状α-Al2O3支撑体上制备出完整无缺陷的截留分子量小于10000的TiO2中孔膜。考察了烧成温度对非担载TiO2粉末和TiO2中孔膜性能的影响。结果表明:在400℃烧成3h可制备出孔径为4.7nm的TiO2中孔膜,其对PEG的截留分子量为8150,在0.8MPa,20℃下,纯水渗透通量为30L/(m2·h),对pH=3的Ni(NO3)2溶液的截留率达到95.14%。     

γ-Al2O3中孔陶瓷膜的制备及表征

以粒径为0.3～0.4 μm的α-Al2O3为原料,通过悬浮液真空抽吸法,制备出平均孔径约为70 nm的完整无缺陷的片状α-Al2O3支撑体;以仲丁醇铝为前驱体,采用颗粒溶胶路线制备出稳定的Boehmite溶胶,以此溶胶采用浸浆法,在制备的α-Al2O3支撑体上制备出完整无缺陷的γ-Al2O3中孔膜,并考察了烧成温度对γ-Al2O3中孔膜性能的影响.结果表明,本文制备出的γ-Al2O3膜的孔径约为3 nm,对PEG的截留分子量为2800～5300,纯水渗透通量为11.5～25.9 L·m-2·h-1[7.6×105 Pa,(14±1)℃].说明在孔径为70 nm左右的载体上直接制备孔径为3 nm的完整的中孔膜是可行的.     

γ-Al2O3中孔陶瓷膜的制备及表征

以粒径为0.3～0.4 μm的α-Al₂O₃为原料,通过悬浮液真空抽吸法,制备出平均孔径约为70 nm的完整无缺陷的片状α-Al₂O₃支撑体;以仲丁醇铝为前驱体,采用颗粒溶胶路线制备出稳定的Boehmite溶胶,以此溶胶采用浸浆法,在制备的α-Al₂O₃支撑体上制备出完整无缺陷的γ-Al₂O₃中孔膜,并考察了烧成温度对γ-Al₂O₃中孔膜性能的影响。结果表明,本文制备出的γ-Al₂ O₃膜的孔径约为3 nm,对PEG的截留分子量为2800～5300,纯水渗透通量为11.5～25.9 L.m^-2.h^-1［7.6×10⁵ Pa,（14±1）℃］。说明在孔径为70 nm左右的载体上直接制备孔径为3 nm的完整的中孔膜是可行的。     

Preparation and characterization of mesoporous γ-Al2O3 membranes

以粒径为0.3～0.4 μm的α-Al₂O₃为原料,通过悬浮液真空抽吸法,制备出平均孔径约为70 nm的完整无缺陷的片状α-Al₂O₃支撑体;以仲丁醇铝为前驱体,采用颗粒溶胶路线制备出稳定的Boehmite溶胶,以此溶胶采用浸浆法,在制备的α-Al₂O₃支撑体上制备出完整无缺陷的γ-Al₂O₃中孔膜,并考察了烧成温度对γ-Al₂O₃中孔膜性能的影响。结果表明,本文制备出的γ-Al₂ O₃膜的孔径约为3 nm,对PEG的截留分子量为2800～5300,纯水渗透通量为11.5～25.9 L.m^-2.h^-1［7.6×10⁵ Pa,（14±1）℃］。说明在孔径为70 nm左右的载体上直接制备孔径为3 nm的完整的中孔膜是可行的。     

Ti/Zr复合纳滤膜的制备及其性能

通过聚合溶胶路线制备出稳定的Ti/Zr(摩尔比=1:1)复合溶胶。采用浸浆法,在平均孔径为5～6 nm的片状a-Al₂O₃/g-Al₂O₃载体上制备出完整无缺陷的Ti/Zr复合纳滤膜。详细考察了焙烧温度对Ti/Zr粉体的影响,并考察了Ti/Zr复合纳滤膜的性能。结果表明:在较高烧成温度下(500℃),Ti/Zr粉体依然呈无定形态且保持微孔结构。在400℃烧成温度下制备出孔径为1.49 nm的Ti/Zr复合纳滤膜,该膜的截留分子量(MWCO)为880,纯水通量为4.3 L·m^-2·h^-1·MPa^-1。在pH=6,压力0.8 MPa的条件下,该膜对0.005 mol·L^-1的MgCl₂、CaCl₂的截留率分别为85%和78%。     

微孔SiO_2膜在水蒸气条件下的稳定性能

以正硅酸乙酯为前驱体,通过聚合溶胶路线制备出稳定的SiO2溶胶和制膜液,采用浸浆法,经过一次涂膜,在平均孔径约为3nm的γ-Al2O3中孔膜上制备出完整无缺陷的SiO2微孔膜,考察了烧成温度对SiO2粉末和SiO2微孔膜气体渗透性能的影响.结果表明,在400～800℃焙烧温度下制备的SiO2膜在200℃及0.3MPa条件下对He的渗透通量为(7.29～12.7)×10-7mol/(m2·s·Pa),600℃下烧成的膜的理想分离因子分别为98(He/CO2),49(He/O2),64(He/N2),79(He/CH4)和91(He/SF6),具有分子筛分效应.微孔SiO2膜在水蒸气条件下的稳定性能取决于膜的烧成温度,400,600和800℃烧成的膜的水蒸气稳定压力分别为8,200和200kPa.     

改进的颗粒溶胶工艺制备高性能ZrO2-TiO2复合纳滤膜

以水为溶剂,采用改进的颗粒溶胶工艺,通过溶胶制备参数的调控优化,制备得到平均粒径为3 nm的ZrO₂-TiO₂复合颗粒溶胶。采用浸浆法,在平均孔径为5 nm的管式α-Al₂O₃底膜上,经过一次涂膜制备得到完整无缺陷的ZrO₂-TiO₂复合纳滤膜。ZrO₂-TiO₂复合纳滤膜的平均膜厚约为200 nm,纯水渗透率约为23 L·m^-2·h^-1·(0.1 MPa)^-1,对PEG的截留分子量为600。在pH 3,压力0.9 MPa的条件下,该膜对低浓度的Co²⁺、Sr²⁺、Cs⁺的截留率分别达到99.6 %、99.2 %和75.5 %。     

湿化学法制备多通道ZrO_2超滤膜

采用孔径为200 nm的多通道ZrO2膜为底膜,利用湿化学法制备小孔径ZrO2超滤膜。结合N2吸附-脱附法和X线衍射分析,考察烧结温度对膜结构的影响,确定合适的烧结温度。通过扫描电镜(SEM)表征膜形貌,采用错流过滤考察膜的渗透和分离性能。结果表明:烧结温度为600℃时可以制备完整无缺陷的ZrO2超滤膜,所制备的超滤膜具有高纯水通量,截留相对分子质量(MWCO)为20 000,对相对分子质量为43 000卵清蛋白的截留率达到95%。     

以PMMA为模板剂制备大孔ZrO_2膜的研究

提高陶瓷膜孔隙率是高性能陶瓷膜制备的重要研究方面,有序大孔材料具有很高的孔隙率。以聚甲基丙烯酸甲酯(PMMA)为成孔模板剂,采用抽滤和重力沉积的组装方法制备了对称的大孔ZrO2膜。实验考察了制膜液的合成条件,通过调节模板剂和ZrO2粒子的电性制得了稳定的制膜液。同时用浸浆法在A l2O3多孔支撑体上制备了非对称大孔ZrO2膜。制得的对称大孔ZrO2膜的孔隙率达到了62%。扫描电子显微镜(SEM)照片显示制备出的ZrO2膜孔径均一,孔排列规则,具有很大的孔隙率。     

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%。     

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.     

铝镁双醇盐制备MgAl2O4尖晶石陶瓷超滤膜

Spinel (MgAl2O4) ultrafiltration membranes were prepared on porous α-Al2O3 plates via the sol-gel route. Mg-Al double alkoxide [MgAl2(iprO)s] was first synthesized as the precursor, then hydrolyzed and peptized in aqueous solution. The gel layer was coated from the colloidal sol on the intermediate layer (α-Al2O3), which was formerly prepared to modify the porous substrate, and then thermally treated at 900℃. The processing parameters such as pH, temperature and sol composition during the sol preparation were optimized for controlling particle size. The pore size of the 2μm thick top layer is about 13 nm as estimated by both the BSA (Bovine Serum Albumin)retention test and an empirical equation.The water permeability of the obtained spinel membrane is 55～143 kg/(min.cm2.Pa).     

多级孔道ZSM-5分子筛超滤膜的制备

利用二次生长法,以十六烷基三甲基溴化铵（CTAB）为结构导向剂,一步水热合成了多级孔道ZSM-5分子筛膜。结果表明,CTAB球形胶束与分子筛颗粒自组装形成了介孔结构,同时,CTAB胶束及疏水长链抑制了晶体的长大。通过调整CTAB/SiO₂摩尔比、合成温度及晶化时间等制膜条件,改变分子筛膜的晶体颗粒尺寸及膜层交联度,实现了分子筛膜介孔结构的有效调节,其孔径范围7~30 nm。在CTAB/SiO₂摩尔比为0.05、合成温度180℃、时间20 h下,多级孔分子筛膜纯水渗透通量达到138 kg·m^-2·h^-1·MPa^-1,截留分子量28500,对应平均孔径7.39 nm,达到小孔径超滤的标准。     

微乳液法制备高分散性纳米氧化锆

利用微乳液法,在表面活性剂(TX-10)-正己醇-环己烷(体积比为1.0∶1.3∶7.7)组成的微乳液体系中,控制反应物浓度为0.02 mol/L,乙醇置换水量为200 mL,焙烧温度为450℃,制得高分散性纳米氧化锆。氮气吸附试验结果表明,纳米氧化锆颗粒表面的孔径分布与其分散性之间存在对应关系。XRD分析显示,产物最初为无定形ZrO2,经450℃焙烧3 h后,氧化锆主要以四方晶相为主,伴随少量单斜晶相,焙烧温度升高至750℃后,得到单一纯净的单斜晶相氧化锆。     

浸渍工艺及烧成温度对SiO2纳滤膜微观结构的影响

以平均粒径为10 nm和80 nm的硅溶胶为主要原料,采用浸渍提拉法在50 nm超滤支撑体上制备了SiO2纳滤膜.研究了烧成温度对膜层密度和气孔率、物相组成、热膨胀及显微结构的影响,探讨了溶胶浓度与膜厚度的关系,确定了合适的烧结温度和镀膜工艺.结果表明:随烧结温度升高至800℃以上时,SiO2纳滤膜的密度显著提高,在850℃以上会析出方石英相,导致其在200℃左右因方石英相变而出现膨胀突变;600℃和700℃分别是10 nm和80 nm硅溶胶制备的SiO2纳滤膜的合适烧结温度;以浓度为16.9wt％的10 nm硅溶胶镀膜在600℃烧成后可以形成微结构均匀、厚度约1μm的SiO2纳滤膜.     

Influence of compatibility between sol and intermediate layer on the performance of yttria-stabilized zirconia nanofiltration membrane

This paper reports the synergistic effect of the sol and intermediate layer on the performance of yttria-stabilized zirconia (YSZ) nanofiltration (NF) membranes. We have focused on the characterization of the microstructure, pure water permeance, and molecular weight cut-off (MWCO) of the NF membranes derived from zirconia sols of different precursor concentrations on two types of supported ZrO₂ ultrafiltration (UF) membranes. We found that the performance of YSZ membranes strongly depends on the sol concentration and the pore size of the intermediate layer. In addition, YSZ gel membrane formation was found to follow the filtration process. Therefore, it is essential to maintain the compatibility between the sol and intermediate layer to fabricate high-performance NF membranes. A crack-free thin YSZ layer with an MWCO of 816 Da (pore size: 1.4 nm) and a water permeance of 25 L m^-2 h^-1 bar^-1 was fabricated using a precursor concentration of 0.03 mol/L, on ZrO₂ UF membrane with a pore size of 5.5 nm. The YSZ NF membrane exhibited a relatively high retention rate towards MgCl₂ (71%), whereas a lower retention rate was observed for NaCl (35%).