石墨烯掺杂聚砜基正渗透膜的结构和性能

采用相转化法分别制备了掺杂有石墨、石墨烯和氧化石墨烯的聚砜正渗透(FO)膜支撑层,通过间苯二胺和均苯三甲酰氯间的界面聚合在支撑层表面制备了聚酰胺活性层。采用扫描电子显微镜(SEM)表征膜表面和断面的结构形貌,测定膜孔隙率和亲水性,考察不同掺杂物时FO膜的性能。结果表明,掺杂石墨烯和氧化石墨烯,支撑层断面结构更加疏松,孔隙率和纯水透过常数(PWP)明显增加,制备的相应FO膜性能得到改善,水通量增大。掺杂石墨则导致支撑层上表面变粗糙,断面结构密实,其孔隙率减小,PWP值降低,膜性能变差。其中,掺杂了氧化石墨烯的FO膜表现出最好的性能,水通量在活性层朝向驱动液侧(AL-DS)模式下可达37.10L/(m~2×h),相比无掺杂FO膜增加了38.7%。     

TiO_2/PVDF改性中空纤维超滤膜的制备与性能表征

采用非溶剂致相分离法制备TiO_2/PVDF改性中空纤维超滤膜,利用傅里叶红外吸收光谱技术、扫描电镜表征了膜的化学组成及微观形态,考察了添加纳米TiO_2粒子对PVDF膜的纯水通量、截留率、机械强度、孔隙率及亲水性等性能的影响。结果表明,与未添加纳米TiO_2粒子的膜相比,其微观结构、亲水性及膜性能均有显著提高;纳米TiO_2粒子的添加有效改善了膜的亲水性及机械强度,但过量添加会造成团聚,从而影响膜的分离性能。纳米TiO_2粒子的质量分数为1%时制得的膜综合性能为优,纯水通量达到了524.3 L/(m2·h),BSA截留率达到了96.3%,拉伸强度为2.69 MPa,断裂伸长率为182%,表面纯水接触角为65.4°,孔隙率为77.9%。     

UiO-66-NH2与季铵盐协同改性正渗透膜及其对染料废水分离性能

为了提高正渗透(FO)膜对染料的分离与抗污染性能，采用共混相转化法将聚对氯甲基苯乙烯(PCMS)引入聚偏氟乙烯(PVDF)多孔支撑底膜中，经UiO-66-NH₂与PCMS上的氯甲基的亲核取代反应，使UiO-66-NH₂均匀地固定在膜表面，进一步通过改进的界面聚合工艺即在其水相溶液中添加苯基三甲基氯化铵(TMPAC)，制备同时具有高渗透性能和抗污染性的FO复合膜。对支撑底膜和FO膜的结构和性能进行分析表征，并通过FO装置测试FO膜渗透分离和抗污染性能。结果表明，UiO-66-NH₂的引入有效提升了FO膜的亲水性、荷电性及渗透性能，界面聚合工艺中季铵盐的加入极大提升了FO膜的分离和抗污染性能。改性后的FO膜(M2-T)纯水通量可达到22.4 L·m^-2·h^-1，对染料废水中罗丹明6G和橙黄G的截留率可达97.82%和99.84%，经过6 h的罗丹明6G运行后，归一化通量衰减率仅为10.18%，纯水通量恢复率仍有95.66%。     

APTES-TiO2-B4C/PVDF膜的制备及其光降解有机染料的性能研究

采用3-氨丙基三乙氧基硅烷（APTES）对纳米碳化硼（B₄C）和二氧化钛（TiO₂）的混合颗粒进行改性,制备出功能化APTES-B₄C/TiO₂复合颗粒。利用相转化技术将APTES-B₄C-TiO₂复合颗粒引入聚偏氟乙烯（PVDF）膜基质中,得到具有光催化性能的APTES-B₄C-TiO₂/PVDF复合膜。通过XRD、SEM、EDS和水接触角测试对制备的复合膜进行表征。以50 mg/L的罗丹明B（RhB）水溶液模拟废水考察APTES-B₄C-TiO₂/PVDF复合膜的光催化性能。结果表明,当复合粒子的质量分数为0.5%时,复合膜具有最高的孔隙率（68.3%）、最大的膜比表面积（8.25 m²/g）和最低的水接触角（69°）。光催化实验结果表明,APTES-B₄C-TiO₂复合粒子的质量分数为0.5%时,A...     

PVDF-TiO2复合中空纤维膜的制备与表征

将纳米二氧化钛(TiO₂)粒子与4类制膜添加剂复配处理,采用相转化法制备聚偏氟乙烯(PVDF)-TiO₂复合中空纤维膜,讨论了纳米TiO₂粒子对复合膜结构和性能的影响。通过扫描电子显微镜、X射线衍射、能谱分析、热重分析、拉伸试验、接触角测定和超滤实验分别表征了复合膜的微观孔结构、晶相结构和复合均匀性、热稳定性、机械性能、亲水性、超滤性能以及抗污染性能。结果表明：通过添加TiO₂粒子复配添加剂,复合膜的性能得到有效改善。复配添加剂中w(TiO₂)为2%(占PVDF固含量的质量分数)时,纯水通量由348 L/(m²·h)提高至377 L/(m²·h),牛血清蛋白截留率由68%提高至90%,断裂强度和抗污染性能提高,复合膜综合性能优异。     

聚苯乙烯磺酸钠对掺混聚偏氟乙烯阴离子交换膜的改性表征

聚苯乙烯磺酸钠（PSS）因含有强电离作用的负电荷基团（磺酸基团）可以和聚偏氟乙烯（PVDF）一起改性阴离子交换膜,使膜在提高稳定性的前提下,保证其他性能。本实验采用浸润改性法,用PSS浸润改性添加了PVDF的阴离子交换膜。探讨了PSS含量对膜性能的影响,如膜电阻、离子交换容量、含水率和选择透过性。利用红外光谱仪及扫描电子显微镜表征手段对膜表面性质和结构进行了分析。结果表明,当PSS含量增加时,膜面电阻先降低后升高,离子交换容量和含水率升高,离子选择透过性先升高后降低。虽然PVDF的添加使阴离子交换膜除稳定性外的其他性能下降,但PSS的浸润改性弥补了这一缺陷,这使得PSS与PVDF复合改性的阴离子交换膜具有一定的实用价值。     

γ-Al2O3/TiO2混合纳米粒子改性PVDF超滤膜

为提高聚偏氟乙烯（PVDF）膜的亲水性和强度,将纳米二氧化钛（TiO2）溶胶和纳米氧化铝（γ-Al2O3）按不同比例与聚偏氟乙烯共混,采用相转化法制得共混超滤膜。考察了不同比例的混合纳米粒子对PVDF超滤膜的纯水通量、截留率、力学性能等的影响。并利用扫描电子显微镜（SEM）观察了膜的表面和内部微观结构,红外光谱分析（FTIR）和X射线衍射仪（XRD）考察纳米粒子在PVDF基体中的存在状态,通过对复合膜进行拉力测试研究混合纳米粒子对膜力学性能的影响,并使用接触角测量仪测定膜表面和水之间的接触角来定量分析比较膜表面的亲水性。结果表明,γ-Al2O3/TiO2混合比为1∶2时,膜的性能达到最优,孔隙率为74%,水通量为120 L/（m2.h）,截留率为93%,拉力最大负荷为35 N,拉伸应变为22%。     

功能化Zr-MOF强化混合基质膜CO2分离

混合基质膜（MMMs）在气体分离领域具有良好的应用前景,金属有机框架（MOFs）由于具有高孔隙率和有机连接基团,常被用作填料制备MMMs。但由于MOFs与聚合物的界面相容性问题,MMMs的气体分离性能提升受到限制。本文合成了功能化的Zr-MOF（UiO-66-AC）,并利用其与聚醚共聚酰胺（Pebax）共同制备了混合基质膜。填料中引入的羰基和羧基等基团提供了MOFs与聚合物基质之间较强的界面相互作用。与纯Pebax膜相比,UiO-66-AC/Pebax MMMs的气体渗透性能得到了显著提高。当填料质量分数为6%时,膜的CO₂渗透系数为102.4 Barrer,CO₂/N₂和CO₂/CH₄选择性分别为90.6和26.0,CO₂/N₂分离性能突破了Robeson上限(2008),表明该混合基质膜在CO₂的分离应用上具有潜力。     

基于硅烷偶联剂表面改性制备Al_2O_3/PVDF杂化膜

采用硅烷偶联剂(2-氰乙基)三乙氧基硅烷对纳米Al_2O_3粒子进行表面改性,利用热致相变法制备了改性Al_2O_3/PVDF有机无机杂化膜,研究了改性Al_2O_3的添加量对杂化膜性能的影响。经(2-氰乙基)三乙氧基硅烷改性后,纳米Al_2O_3粒子的团聚减少,改性后纳米Al_2O_3的平均最小粒径为52.23nm。与纯PVDF膜比较,改性纳米Al_2O_3的添加改善了PVDF膜的形貌结构,改性Al_2O_3/PVDF杂化膜形成的球晶明显增加,球晶的密度尺寸缩小,杂化膜中形成了大量连通的界面孔,膜的孔隙率升高,改善了PVDF膜的力学性能和亲水性,提高了截留率。当纳米粒子添加量达到5%时,膜的截留率提高了7.2%,膜的纯水通量达到了593.95L/(m~2·h),膜强度达到5.0MPa。     

聚砜/纳米TiO2有机-无机复合超滤膜的制备与表征

用阴离子表面活性剂改性的纳米TiO2,加入到聚砜铸膜液中,采用相转化法制备了分散均匀的聚砜/ TiO2复合超滤膜.通过测定纯水通量、对牛血清蛋白的截留率、水接触角、粘度、抗污染性、机械强度等实验,研究了不同TiO2加入量对膜的超滤性能和力学性能的影响.并在扫描电镜下观察了膜的表面与断面形态,测定了膜的孔密度、孔隙率、孔径及其分布,从而考察了添加纳米TiO2对膜微观结构的影响.结果表明,当纳米TiO2的加入量为2%(wt)时,膜的孔隙率增大,平均孔径减小;同时膜的性能得到了明显的改善,纯水通量提高了69%,同时膜的抗压强度和断裂强度也分别提高了50%和26.7%,并且膜的亲水性也明显增强,水接触角由72.1度降低到41.4度,从而使膜的抗污染性明显改善.但进一步增加TiO2的浓度(3%(wt)以上),膜的机械强度、亲水性和超滤性能反而下降.因此在聚砜膜中适量地添加纳米TiO2粒子,可明显改善膜的亲水性和力学性能,提高膜的通量,增强膜的抗污染能力,从而拓宽了膜的应用领域.     

Effects of pre-oxidant (KMnO4) on structure and performance of PVDF and PES membranes

The structure and performance of membrane materials are very important to the efficient and stable operation in membrane drinking water purification technology. Potassium permanganate (KMnO₄), which can change the characteristics of organic matters and control membrane surface fouling, has been widely used as pre-oxidant in the front of membrane drinking water process. This study investigates the evolution of membrane surface structure and performance when polyvinylidene fluoride (PVDF) and polyethersulfone (PES) were exposed to 10, 100 and 1000 mg·L^-1 KMnO₄ solution for 6 and 12 d, respectively. The aged membrane physicochemical characteristics such as membrane surface morphology, chemical composition, hydrophilicity, porosity and zeta potential were evaluated by modern analytical and testing instruments. The anti-fouling property of membrane surface was also investigated by the filtration-backwash experiment. The results indicated that the different concentrations and exposure time of KMnO₄ led to a different variation on PVDF and PES membrane surface structure and performance, which could further affect the membrane separation performance and the membrane fouling behaviors. The membrane surface pore size and porosity increased due to the dislodgment and degradation of membrane additive (PVP), which improved membrane permeability and enhanced the adsorption and deposition of pollutants in the membrane pores. With the increase of exposure time, the membrane surface pore size and porosity reduced for the reactions of chain scission and crosslinking on membrane materials, and the backwashing efficiency declined, leading to a more serious irreversible fouling. Compared with PVDF membranes, the formation of sulfonic group for PES membranes increased the negative charge on membrane surface due to the oxidation of KMnO₄. The present study provides some new insights for the regulation of the pre-oxidant dose and the selection of the membrane materials in KMnO₄ pre-oxidation combined with membrane filtration system.     

Poly(ethylene glycol) crosslinked sulfonated polysulfone composite membranes for forward osmosis

Forward osmosis (FO) membranes were prepared by a coating method with poly(ethylene glycol) crosslinked sulfonated polysulfone (SPSf) as a selective layer. The poly(ether sulfone)/SPSf substrate was prepared by phase inversion. The composite membranes were characterized with respect to membrane chemistry (by attenuated total reflectance/Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy), hydrophilicity (by static contact angle measurement), and surface morphology (by scanning electron microscopy and atomic force microscopy). The FO performance was also characterized. The effects of the crosslinker concentration on the hydrophilicity and FO performance were investigated. The crosslinked membrane exhibited a high hydrophilicity with a lowest contact angle of 15.5°. Under FO tests, the membranes achieved a higher water flux of 15.2 L m^?2 h^?1 when used against deionized water as the feed solution and a 2 mol/L sodium chloride (NaCl) solution as the the draw solution. The membranes achieved a magnesium sulfate rejection of 96% and an NaCl rejection of 55% when used against a 1 g/L inorganic salt solution as the feed solution and a 2 mol/L glucose solution as the draw solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43941.     

商业正渗透膜的改性及其用于处理焦化废水的研究

正渗透技术是一种新兴的膜分离技术，在处理有机废水方面具有广阔的应用前景。分别对Poten以及HTI商业正渗透膜进行改性，并用于对焦化废水中难降解毒性小分子(吲哚和吡啶)的截留测试。探究了水相单体PIP浓度、膜朝向、汲取液浓度对改性前后两种膜水通量、J_s/J_w比值、有机物截留率的影响，以及改性前后两膜特征参数的变化。结果表明：对Poten膜和HTI膜进行界面聚合改性后，膜水通量以及J_s/J_w比值都不同程度地降低；改性后的两正渗透膜水渗透系数A、盐渗透系数B均降低，而膜结构参数S以及对NaCl和有机物的截留率均提高；其中HTI-IP复合膜对有机物的截留率(81%)明显高于IP-2(改性Poten膜)复合膜；与FO模式相比，IP-2复合膜在PRO模式下(汲取液面向活性层)具有更高的水通量及反向盐通量。此外，在两种膜朝向下，水通量及反向盐通量都随汲取液浓度的增大而增大，但是在FO模式下(料液面向活性层)，通量呈现非线性增长。     

Improvement of porous polyvinylidene fluoride-co-hexafluropropylene hollow fiber membranes for sweeping gas membrane distillation of ethylene glycol solution

Porous polyvinylidene fluoride-co-hexafluropropylene (PVDF-HFP) hollow fiber membranes were fabricated through a wet spinning process. In order to improve the membrane structure, composition of the polymer solution was adjusted by studying ternary phase diagrams of polymer/solvent/non-solvent. The prepared membranes were used for sweeping gas membrane distillation (SGMD) of 20 wt% ethylene glycol (EG) aqueous solution. The membranes were characterized by different tests such as N₂ permeation, overall porosity, critical water entry pressure (CEP_w), water contact angle and collapsing pressure. From FESEM examination, addition of 3 wt% glycerol in the PVDF-HFP solution, produced membranes with smaller finger-likes cavities, higher surface porosity and smaller pore sizes. Increasing the polymer concentration up to 21 wt% resulted in a dense spongy structure which could significantly reduce the N₂ permeance. The membrane prepared by 3 wt% glycerol and 17 wt% polymer demonstrated an improved structure with mean pore size of 18 nm and a high surface porosity of 872 m^-1. CEP_w of 350 kPa and overall porosity of 84% were also obtained for the improved membrane. Collapsing pressure of the membranes relatively improved by increasing the polymer concentration. From the SGMD test, the developed membrane represented a maximum permeate flux of 28 kg·m^-2·h^-1 which is almost 19% higher than the flux of plain membrane. During 120 h of a long-term SGMD operation, a gradual flux reduction of 30% was noticed. In addition, EG rejection reduced from 100% to around 99.5% during 120 h of the operation.     

ZnO修饰的不锈钢网支撑体上ZIF-8膜的制备

ZIF-8因具有0.34 nm的孔道直径而被认为是最具应用前景的气体分离膜材料之一。不锈钢网（SSN）作为分离膜的支撑体具有价格低廉、易于裁剪、厚度薄等优点。采用水热法在SSN表面生长ZnO缓冲层,以ZnO修饰的SSN（ZnO/SSN）为支撑体制备ZIF-8膜。采用X射线衍射（XRD）和扫描电子显微镜（SEM）对合成的ZIF-8膜进行表征,并进行了气体渗透性能测试,结果表明,在ZnO颗粒修饰后的SSN支撑体上无需活化可制备出单一物相、无缺陷的ZIF-8膜;在室温（298 K）下,ZIF-8膜的H₂/CO₂、H₂/N₂、H₂/CH₄的理想分离系数分别为7.3、9.2、12.4;在150℃,ZIF-8膜的渗透性能稳定。     

Preparation of blend polyethersulfone/cellulose acetate/polyethylene glycol asymmetric membranes for oil–water separation

Blend PES/CA hydrophilic membranes were prepared via a phase-inversion process for oil–water separation. PEG-400 was introduced into the polymer solution in order to enhance phase-inversion and produce high permeability membranes. A gas permeation test was conducted to estimate mean pore size and surface porosity of the membranes. The membranes were characterized in terms of morphology, overall porosity, water contact angle, water flux and hydraulic resistance. A cross-flow separation system was used to evaluate oil–water separation performance of the membranes. From FESEM examination, the prepared PES/CA membrane presented thinner outer skin layer, higher surface porosity with larger pore sizes. The outer surface water contact angle of the prepared membrane significantly decreased when CA was added into the polymer solution. The higher water flux of the PES/CA membrane was related to the higher hydrophilicity and larger pore sizes of the membrane. From oil–water separation test, the PES/CA membrane showed stable oil rejection of 88 % and water flux of 27 l/m² s after 150 min of the operation. In conclusion, by controlling fabrication parameters a developed membrane structure with high hydrophilicity, high surface porosity and low resistance can be achieved to improve oil rejection and water productivity.     

聚乙烯醇-SiO2/聚酯无纺布膜的制备及性能研究

采用聚酯无纺布(PET)作为支撑层,利用相转换法在PET表面制备聚乙烯醇(PVA)或PVA-SiO₂活性层,得到了PVA/PET复合膜与PVA-SiO₂/PET复合膜。考察了2种复合膜的过滤性能和污染行为。结果表明,PVA中加入质量分数4%纳米SiO₂颗粒,复合膜的接触角降至33.1o,亲水性显著增强,而膜孔径减小至3.1 nm,降低了85.5%,PVA/PET超滤膜转变为PVA-SiO₂/PET纳滤膜(0.6 L/(m²·h))。PVA-SiO₂/PET复合纳滤膜对海藻酸钠的抗污染性能较强。纳米SiO₂对复合膜的污染机制无明显影响,模拟污染物对复合膜的污染机制以标准堵塞为主。     

Synthesis and characterization of low content of different SiO2 materials composite poly (vinylidene fluoride) ultrafiltration membranes

A comparison of the morphology and performance of virgin poly (vinylidene fluoride) (PVDF) ultrafiltration (UF) membrane, and PVDF-composite membranes with low content of two different SiO₂ (N-SiO₂ and M-SiO₂ particles) was carried out. Cross-sectional area and surface morphology of the membranes were observed by scanning electron microscopy and atomic force microscopy. Surface hydrophilicity of the porous membranes was determined through the measurement of a contact angle. Performance tests were conducted on the composite membranes through water flux and bovine serum albumin (BSA) retention. Average pore size and surface porosity were calculated based on the permeate flux. Thermal stability and mechanical stability were determined by thermogravimetric analysis and tensile stress tests. The results indicate that N-SiO₂/PVDF (P-N) membranes possessed larger average pore size and porosity, which led to higher water flux and a slight decline in BSA retention. On the other hand, M-SiO₂/PVDF (P-M) membranes had better mechanical stability and anti-fouling performance with enhanced membrane hydrophilicity and decreased membrane surface roughness. Both of the P-N and P-M membranes exhibited typical asymmetric morphology and improved thermal stability.     

聚丙烯微孔膜的表面矿化修饰及其亲水性能

为了改善聚丙烯微孔膜(MPPM)的表面亲水性,通过组合多巴胺氧化聚合和交替浸渍矿化修饰技术,在MPPM表面构建了均匀的CaCO₃矿物层,实现了利用CaCO₃矿物对膜表面进行亲水化修饰的目的。采用FTIR、XPS、ESEM、EDX和水接触角对矿化膜表面进行了相应的表征。考察了溶液浓度、浸渍循环次数及聚多巴胺涂覆率等对CaCO₃矿化率的影响。结果证实,CaCO₃矿物均匀地负载在MPPM表面,膜的亲水性因CaCO₃固有的润湿性而明显改善。纯水通量测试结果表明,矿化膜具有强的水渗透能力,纯水通量大(高达6450 L·m^-2·h^-1),渗透阻力小,施加0.01 MPa的外压,水即可透过膜。油水乳液分离研究发现,矿化膜能有效地分离一定范围的油水乳液,水通量大(> 1800 L·m^-2·h^-1),且膜容易用水清洗,展现出理想的油水乳液分离应用前景。