原位界面聚合制备PVDF复合纳滤膜的研究

为改善聚偏氟乙烯(PVDF)复合纳滤膜性能，以掺入单体哌嗪(PIP)的铸膜液制备基膜，通过原位界面聚合快速制备复合纳滤膜，简化了制备程序。ATR-FTIR分析结果表明，基膜上成功生成聚酰胺(PA)层，SEM观察到PA层表面具有典型结节结构。得到的复合纳滤膜对Na₂SO₄截留率为95.59%,渗透通量为12.37 L/(m²·h·bar),远高于传统界面聚合制备的PVDF复合纳滤膜。72 h的持续测试结果表明该复合纳滤膜具有良好的长期稳定性。     

PA/ZIF-8/PVDF复合纳滤膜的制备及其性能

采用反向扩散法在聚偏氟乙烯(PVDF)基膜表面原位生长一层均匀、致密的金属有机骨架材料ZIF-8纳米晶体层,并进一步优化界面聚合反应,制备高性能聚酰胺(PA)/ZIF-8/PVDF复合纳滤膜.采用SEM、XRD、FTIR、AFM、XPS、水接触角测定仪以及固体表面Zeta电位仪对ZIF-8/PVDF复合膜及PA/ZIF-8/PVDF复合纳滤膜的组成、结构和形貌进行了表征,考察了ZIF-8亚层的生长对界面聚合反应、复合纳滤膜结构及性能的影响.结果表明,ZIF-8晶体亚层在PVDF膜表面的均匀连续生长改善了PA分离层与PVDF基膜的界面相容性,提高复合纳滤膜PA分离层的交联度.在0.6 MPa下,复合纳滤膜纯水通量可达24.05 L/(m2·h),对MgSO4、Na2SO4、NaCl和MgCl24种盐的截留率分别达到97.34％、93.57％、89.31％和85.16％,具有优异的抗污染性能.     

荷正电季铵化壳聚糖/聚醚酰亚胺复合纳滤膜的制备及性能研究

以无纺布增强具有耐溶剂、耐热特性的聚醚酰亚胺(PEI)超滤(UF)膜为支撑层,具有荷正电性和良好成膜性的2-羟丙基三甲基氯化铵壳聚糖(HACC)为功能层,制备了一种荷正电HACC/PEI复合纳滤(NF)膜。考察了聚合物浓度、反应时间、交联剂浓度及交联温度等对所制备的复合纳滤膜性能的影响,并利用扫描电镜(SEM)观察了该复合纳滤膜的表面形貌。结果表明:最佳制备条件下得到的HACC/PEI复合纳滤膜在0.3 MPa、20℃下对MgCl2具有较好的分离效果,其通量和截留率分别为10.9 L/(m2·h)和83.1%;另外,HACC/PEI复合纳滤膜呈现典型的荷正电特征,对二价无机盐具有较高的截留率。     

单宁酸-多巴胺涂覆制备染料分离用纳滤膜

通过单宁酸及聚多巴胺涂覆,制备了单宁酸(TA)-聚偏氟乙烯(PVDF)纳滤膜,同时评价了改性膜对刚果红、伊文思蓝、活性嫩黄等染料的分离性能。结果表明,改性后膜表面粗糙度略微增大,亲水性明显增强。同时,改性膜具有水下超疏油的性质,能够完全抵抗水下油污的污染。2wt% TA-PVDF纳滤膜对多种染料的截留率能达到96.5%以上,且对刚果红、伊文思蓝、活性嫩黄等染料的截留通量都超过65.7 L/(m2?h?bar)。另外,改性膜在染料分离时截留通量基本不变,稳定性较强,在工业染料废水处理方面有一定的应用前景。     

聚偏氟乙烯膜亲水改性及其乳液分离与重金属吸附应用

聚偏氟乙烯（PVDF）膜因其优异的化学和力学稳定性而被广泛应用于水处理领域,但PVDF膜本身的疏水性,容易使其在处理含油废水的过程中被油滴污染,造成膜孔堵塞。以PVDF微滤膜为基底,通过单宁酸（TA）和聚乙烯亚胺（PEI）共沉积形成了TA/PEI黏附层,经戊二醛共价交联和接枝半胱氨酸（Cys）,制备了一种PVDF改性膜（PVDF@TA/PEI-Cys）。改性后的PVDF膜具有良好的亲水性和水下超疏油性,水接触角和水下油接触角分别为22.2°和150.2°。在0.09 MPa下,PVDF@TA/PEI-Cys膜的纯水通量达6328 L/（m²·h）,水包油型乳液分离效率高达99.9%。此外,该改性膜还可同时吸附水中的汞离子,最大吸附量为24.7 mg/g。     

磺化杂萘联苯共聚醚砜/聚醚砜复合纳滤膜的制备

以磺化杂萘联苯共聚醚砜(SPPBES)为功能层材料,聚醚砜(PES)超滤膜为支撑层,采用涂覆法制备了SPPBES/PES复合纳滤膜。研究了SPPBES磺化度、热处理条件等因素对复合纳滤膜性能的影响,并考察了SPPBES/PES复合纳滤膜的耐热性和耐氧化性能。结果表明,SPPBES/PES复合纳滤膜对Na_2SO_4的脱除率可以达到85%,并表现出良好的耐热性和优异的耐氧化性。     

聚偏氟乙烯超滤膜仿生矿化增强及其抗压密性能的研究

通过仿生矿化技术在PVDF超滤膜表面和孔壁修饰无机ZrO_2矿化层来制备PVDF/ZrO_2矿化膜,考察矿化时间对膜的微观结构、机械强度和抗压密性能的影响。结果表明,ZrO_2矿化层均匀负载于膜表面和膜孔内壁,且随着矿化时间的增加矿化层逐渐增厚;无机ZrO_2矿化层可显著提高PVDF膜的结构刚性,矿化时间为60 min的PVDF/ZrO_2矿化膜的拉伸强度和硬度比纯PVDF膜分别提高了76%、79%,运行过程中因机械压密产生的通量衰减率则从纯PVDF膜的53%降低至32%,达到利用ZrO_2矿化层提高PVDF膜抗压密性能、抑制通量衰减的目的。同时,ZrO_2矿化层改善了PVDF膜的透水性能,PVDF/ZrO_2矿化膜的纯水通量和BSA截留率分别达到165.2 L/m~2·h和91.4%。     

TiO2纳米粒子对PVDF超滤膜的结构与性能影响研究

采用溶胶-凝胶法制备了不同纳米TiO2溶胶含量的TiO2/PVDF超滤膜,探讨TiO2溶胶及其含量对膜性能及结构的影响,并利用X射线衍射、扫描电子显微镜、红外光谱和接触角测量仪表征了复合膜的结构.结果表明,经纳米TiO2溶胶改性后,TiO2/PVDF复合膜的孔隙率、接触角和结构等都发生了显著的变化,在TiO2溶胶添加质量分数为4％时条件下,膜的孔隙率为74.5％,水通量为430.6L·m-2·h-1,截留率为82.5％.     

自组装改性纳滤膜研究

荷电纳滤膜可以在膜表面吸附不带电或者携带异种电荷的微粒。本文采用荷负电的聚哌嗪酰胺纳滤膜和强正电载体聚乙烯亚胺(PEI)进行改性试验,PEI胶体通过自组装在膜表面形成致密层。针对不同的PEI质量分数、相对分子质量和反应时间,确定了优化条件。结果表明,经过改性的聚哌嗪酰胺纳滤膜对NaCl、NaF、MgCl2等无机盐的截留性能和膜的水通量均有所提高。     

静电喷雾制备NH2-UIO-66(Zr)复合纳滤膜及其性能研究

利用静电喷雾方法成功制备了聚乙烯亚胺(PEI)/均苯三甲酰氯(TMC)荷正电纳滤膜,并在此基础上引入NH₂-UIO-66(Zr),进一步提升了复合纳滤膜的性能。通过FTIR、SEM、EDS、Zeta电位等表征手段研究了复合膜结构、形貌和表面电荷,并采用错流测试装置对不同重金属溶液进行分离性能测试。结果表明,当MOFs的添加量为0.01 wt%时,制备出的复合纳滤膜性能最优,通量为8.9 L·m^-2h^-1 bar^-1,对NiCl₂的截留率为90%,较空白纳滤膜的通量提高26%且未牺牲截留效果。此外,NH₂-UIO-66(Zr)复合纳滤膜对Cu Cl₂的截留效果大于90%,且稳定性较好,该工作为制备荷正电纳滤膜提供了参考。     

氯化聚氯乙烯复合纳滤膜的制备及其在模拟RB5染料废水处理中的应用

以氯化聚氯乙烯（CPVC）超滤膜为基膜,采用单宁酸（TA）和哌嗪（PIP）在CPVC膜表面共沉积后与交联剂均苯三甲酰氯（TMC）进行界面聚合得到PA/TA/CPVC复合纳滤膜,采用扫描电镜（SEM）、原子力显微镜（AFM）、红外光谱及接触角对PA/TA/CPVC复合纳滤膜进行了表征,并探讨了干燥时间、TA/PIP浓度比、TA+PIP总浓度、TMC浓度对PA/TA/CPVC复合纳滤膜微观结构与性能的影响。结果表明,TA/PIP浓度比最佳为7/3,TA/PIP层的最佳干燥时间为20min,PA/TA/CPVC复合纳滤膜的纯水通量随着TA+PIP总浓度的增加和TMC浓度的增加而减少,对PEG1000的截留率均在90%以上。PA/TA/CPVC复合纳滤膜纯水通量最大值为4.5L/(m² · h · bar),此时PEG1000的截留率达到95.8%。对模拟RB5染料废水的最大通量为4.3L/(m² · h · bar),此时RB5的截留率为95.4%,对模拟RB5染料废水的稳定性较好。     

Novel polyethyleneimine/TMC-based nanofiltration membrane prepared on a polydopamine coated substrate

Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations (such as Mg²⁺ or Ca²⁺), we utilized polyethyleneimine (PEI) and trimesoyl chloride (TMC) to perform interfacial polymerization reaction on a polydopamine coated hydrolyzed polyacrylonitrile substrate to obtain a positively charged nanofiltration membrane. Effects of polydopamine coating time, PEI concentration, TMC reaction time and concentration on the membrane physicochemical properties and separation performance were systematically investigated using scanning electron microscopy, streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions (93.6±2.6% for MgSO₄, 92.4±1.3% for MgCl₂, and 90.4±2.1% for Na₂SO₄), accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L·m⁻²·h⁻¹ at an applied pressure of 8 bar (salt concentrations were all 1000 mg·L⁻¹). The synthesized membranes showed promising potentials for the applications of water softening.     

Hydrophilic polymeric membrane supported on silver nanoparticle surface decorated polyester textile: Toward enhancement of water flux and dye removal

A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF), polyethylene glycol(PEG) as hydrophilic agent, zeolitic like framework-67(ZIF-67), ethylenediamine as cross-linking agent on Ag-nanoparticle-decorated polyester textile(PT) support(PT/AgNPs/PVDF-PEG/ZIF-67). PT/Ag-NPs/PVDF-PEG/ZIF-67 morphology, crystalline structure, surface chemical composition and hydrophilicity of PT/Ag-NPs/PVDF-PEG/ZIF-67 were fully characterized by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR) and water contact angle technique, respectively. PT/Ag-NPs/PVDF-PEG/ZIF-67 was applied in cross module set-up for removal of contaminated water containing rose bengal(RB) dye. The effect of operational parameters such as dye concentration,solution pH and flow rate on performance of PT/Ag-NPs/PVDF-PEG/ZIF-67 were investigated and optimized by central composite design(CCD). Casting solution containing 0.5 wt.% ZIF-67 as optimum value showed the good wettability, high pure water flux(PWF; 35.8 L·m~(-2)·h~(-1)), flux recovery ratio(FRR;90%), dye removal efficiency(96.41%). The selectivity factor of 12.72 and 14.42 was found to be for RB in the presence of amido black and methylene blue as interferent dyes, respectively, which showed a good selective recognition ability for RB dye.     

光催化膜对水中腐植酸的去除及积垢机理

利用湿式相转化方法制备TiO₂/聚苯砜（polyphenylsulfone,PPSU）/聚醚亚硫胺（polyetherimide,PEI）催化膜应用于水中腐植酸（humic acid,HAs）的去除及积垢机理研究。结果表明,随着亲水性PEI比例增加,光催化膜的纯水通量和HAs的过滤通量越大,去除效率越低;且随着光照时间的延长去除效率越趋于稳定,且有回复的现象。在0.2MPa操作压力下,制备的TiO₂/PPSU/PEI （1%/50%/50%）膜具有最佳的可逆阻抗力比例（R_c/R_t=48.24%）;其渗透通量、HAs去除效率及反洗后通量分别为34.0L/（m²·h）、63.2%及22.5L/（m²·h）,具有较佳的通量及HAs去除效率。     

Preparation and characterization of PVDF-PFSA flat sheet ultrafiltration membranes

High performance polyvinylidene fluoride (PVDF) flat sheet ultrafiltration (UF) membranes have been prepared by an immersion precipitation phase inversion method using perfluorosulfonic acid (PFSA) as a pore former and as a hydrophilic component of the membranes and polyethylene glycol (M_w = 400) (PEG400) as a pore forming agent. The effects of the presence of PEG and the concentration of the PFSA on the phase separation of the casting solutions and on the morphologies and performance of UF membranes including their porosity, water flux, rejection of bovine serum albumin (BSA) protein, and anti-fouling property were investigated. Phase diagrams, viscosities and the phase separations upon exposure to water vapor showed that both PEG400 and PFSA promoted demixing of the casting solution. Scanning electron microscopy measurements showed that the PVDF-PFSA blend membranes had more macropores and finger-like structures than the native PVDF membranes. The PVDF-PFSA membrane (5 wt-% PEG400+ 5 wt-% PFSA) had a pure water flux of 141.7 L/m²·h, a BSA rejection of 90.1% and a relative pure water flux reduction (RFR) of 15.28%. These properties were greatly superior to those of the native PVDF membrane (pure water flux of 5.6 L/m²·h, BSA rejection of 96.3% and RFR of 42.86%).     

二氧化钛调控基膜结构对氧化石墨烯复合膜性能的影响

以聚醚砜(PES)超滤膜为基膜,通过聚多巴胺(PDA)表面改性后压力沉积不同量的二氧化钛(TiO₂)纳米粒子作为基底,再沉积氧化石墨烯(GO)片层制得TiO₂/GO复合分离膜,重点考察基膜表面形貌对GO膜分离性能的影响。通过扫描电子显微镜、接触角测试仪、固体表面Zeta电位分析仪、X射线衍射分析仪等对有无TiO₂沉积层的GO复合膜进行表征,并考察TiO₂沉积量对GO复合膜分离性能的影响。结果表明,TiO₂纳米粒子以团簇状态均匀分布在改性的超滤膜表面,随TiO₂沉积量的增加,团簇密度增大,GO沉积后表层的峰谷结构更为明显,但表层的层间距并无明显改变。TiO₂/GO复合膜的水通量随TiO₂沉积量的增加而明显增大,TiO₂的沉积对GO沉积量低的复合膜通量的影响更明显,当 GO沉积量为4.11 μg/cm²,TiO₂沉积量为20.55 μg/cm²时,复合膜的水通量较无TiO₂的复合膜提高了108.38%。复合膜对无机盐溶液的截留性能主要基于膜表面所带负电的道南排斥作用,TiO₂/GO复合膜对刚果红的截留率在99%以上,对甲基橙的截留率可达82%,TiO₂层的加入并未降低复合膜的截留效果。     

氧化石墨烯-陶瓷复合纳滤膜的层层自组装制备及其性能

氧化石墨烯（GO）的片层边缘含有 COOH等含氧官能团,因而带负电荷,可以在带正电荷多孔基体上通过层层自组装实现快速沉积。以由3-氨丙基三乙氧基硅烷（APTES）修饰的多孔氧化铝管式陶瓷膜为基膜,令GO和聚乙烯亚胺（PEI）以溶液形态在其表面交替沉积实现自组装,继以环氧氯丙烷（ECH）交联之,制备新型氧化石墨烯-陶瓷复合纳滤膜。最佳制备工艺是,PEI浓度5 g·L^-1、pH=9,NaCl浓度0.3 mol·L^-1,GO浓度0.6 mg·ml^-1、pH 4.5,层数2层,ECH用量6.25 ml·L^-1,50℃条件下处理70 min。层数为1～4层的自组装膜在0.6 MPa操作压力下对2 g·L^-1的MgCl₂的截留率分别为90.16%、93.71%、97.54%、92.93%,其中1层自组装膜的渗透通量为21.92 L·m^-2·h^-1。氧化石墨烯-陶瓷复合纳滤膜对4种无机盐的截留率大小为MgCl₂ >MgSO₄ > NaCl >Na₂SO₄,符合典型正电荷纳滤膜的特征。     

用于喷墨印花染料纯化的自组装GO/TiO2复合纳滤膜的制备

数码喷墨打印技术对墨水高纯度和低含盐量要求,不断促使染料纯化技术的开发与研究。基于氧化石墨烯(GO)/纳米二氧化钛(TiO₂)自组装的纳滤膜材料的开发,探究了纳米TiO₂颗粒尺寸和与GO共混比例,所获最优GO/TiO₂复合纳滤膜中TiO₂颗粒尺寸为60 nm,与GO共混比例为1∶1。其纯水通量为10.69 L/(m²·h·bar),对NaCl和Na₂SO₄的截留分别为12.6%和15.7%,对铬黑T、刚果红和考马斯亮蓝R的截留均高于99%。采用自制的连续恒容渗滤装置对粗品墨水进行染料脱盐浓缩的实验,所获染料的浓度由最初的2.0 g/L浓缩至9.74 g/L,NaCl和Na₂SO₄浓度则由起始10 g/L分别下降至5.3 mg/L和11 mg/L,满足数码印花对墨水高纯度以及低盐度的要求。     

涂覆法制备高性能磺化聚醚砜混合基质膜

采用涂覆法将磺化聚醚砜（SPES（浓度为0.7%（质量（的铸膜液制备成膜，并使用钛酸四丁酯（TBT（和TiO₂纳米颗粒作为添加剂来对比改善膜性能。通过对纳滤膜的微观结构表征，以及膜对NaCl与染料的分离性能等方面来分析其性能。当钛酸四丁酯的含量为0.35%（质量（时，膜的通量从27.3 L·m^-2·h^-1提升至38.9 L·m^-2·h^-1，而截留率则有91.2%降至82.5%。与纯SPES膜相比，改性纳滤膜的平均孔径更大，由1.51 nm增大为2.28 nm。TBT改性膜表面有TiO₂纳米颗粒形成，而且随着TBT的浓度增大，颗粒逐渐增大，而直接添加TiO₂纳米颗粒的纳滤膜的表面呈现明显的团聚现象。使用钛酸四丁酯代替TiO₂纳米颗粒作为添加剂，在增加膜通量的同时也能降低纳米颗粒团聚而导致的膜缺陷。由钛酸四丁酯水解生成的正丁醇的致孔作用对膜的性能具有很大的影响。     

High permeability poly(vinylidene fluoride) ultrafiltration membrane doped with polydopamine modified TiO2 nanoparticles

In order to improve the water permeability of poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes with low molecular weight cut-off (MWCO), polydopamine (PDA) was employed in the membrane preparation process. Owing to its merits of material-independent adhesion, PDA was coated on inorganic particles or added in coagulation bath to tailor the final membrane structure and property. The introduction of PDA broke through the permeability/selectivity trade-off of the PVDF membrane. By adding the PDA coated titanium dioxide (PDA/TiO₂) nanoparticles, water flux increased by 287% while MWCO kept similar with the pristine PVDF membrane. Thermodynamics and Kinetics of the PVDF/additives/non-solvent were analyzed and shown that nanoparticles reduced the thermodynamic stability and increased the phase separation speed, and the speed can be adjusted using different nanoparticles. Additionally, X-ray diffraction (XRD) test indicated that PVDF crystalline form changed from α phase to β phase after adding different nanoparticles. Permeability/selectivity trade-off was broken through by DA addition in coagulation bath. Compared with the original PVDF membrane, when the DA concentration of the coagulation bath was 2.0 g·L^-1, water flux increased by 312%, and MWCO of the PVDF membrane ranged in 10,000 to 20,000 Da as well as contact angle decreased from 81.4° to 45°.