超疏水聚偏氟乙烯复合微孔膜的制备及性能

提出了一种超疏水聚偏氟乙烯（PVDF）复合微孔膜的制备方法。以相转化法制备的PVDF膜为基膜,通过恒压过滤将多壁碳纳米管（MWCNTs）沉积到PVDF基膜表面,再经聚二甲基硅氧烷（PDMS）溶液修饰,可制得接触角达162°、滚动角约10°的PVDF复合微孔膜。用原子力显微镜和扫描电镜对膜表面进行结构分析,并测试了膜的接触角、气通量和机械强度等性能,考察了MWCNTs及PDMS浓度对膜结构和性能的影响。研究表明,CNTs在具有微米级粗糙度的基膜上强化了纳米结构,提高了膜的粗糙度,PDMS降低了膜的表面能,二者协同作用使复合膜的接触角大幅提高,滚动角显著下降。与高度疏水的PVDF基膜相比,PVDF复合膜的疏水性大幅提高,断裂伸长率加倍,在模拟海水真空膜蒸馏过程中,保持了较高的传质通量和截留率,具有更好的操作稳定性和抗污染性能。     

热致相分离法制备聚偏氟乙烯中空纤维微孔膜的研究

利用热致相制膜技术,选择三种常用的液体稀释剂(邻苯二甲酸二丁酯,1,4-丁内酯,磷酸三丁酯)、两种固体稀释剂(二苯甲酮,碳酸二苯酯),制备出PVDF中空纤维膜并对膜性能进行表征。当PVDF/稀释剂体系降温发生固-液相或窄的液-液相分离时,制得膜为球粒堆积结构,强度差,通量高。随着PVDF/稀释剂体系液-液相分离区的增加,制得膜转变为双连续结构,强度增加。     

膜蒸馏用PVDF抗复合污染膜的制备与测试

为提高膜的抗污染能力,对聚偏氟乙烯（PVDF）平板膜进行表面涂覆改性,得到超疏水PVDF平板膜,再将超疏水PVDF平板膜进行表面亲水化改性,制备出超疏水/亲水复合PVDF膜。当PVDF的质量浓度为2%、聚乙二醇（PG）的质量浓度为39%、涂敷液温度为50℃、蒸发时间为10 s、凝固浴温度为60℃时,超疏水PVDF平板膜接触角达到154.8°。表面亲水改性制得的PVDF超疏水/亲水复合膜的接触角为41°。然后研究了超疏水PVDF平板膜和PVDF超疏水/亲水复合膜的抗膜污染性能。结果显示,超疏水PVDF平板膜具有优良的抗无机污染性能和一定的抗有机污染性能;PVDF超疏水/亲水复合膜不仅具有优良的抗无机污染性能,而且其抗复合污染性能尤其是抗有机污染性能得到明显提升,为进一步构建高性能膜蒸馏抗污染膜提出了一个可行的技术方向。     

利用碳量子点制备紫外线屏蔽PVDF复合薄膜

提供了一种制备紫外线屏蔽聚偏氟乙烯(PVDF)薄膜的简单、有效的方法。首先通过水热法制备有着很好紫外线吸收性能的碳量子点(CQDs),然后将碱溶液处理过的PVDF膜浸于CQDs/聚乙烯醇(PVAL)混合溶液中,在PVDF膜表面形成紫外线屏蔽层。通过傅里叶变换红外光谱仪、X射线光电子能谱分析、X射线衍射、透射电镜和紫外–可见分光光度计对CQDs颗粒的结构、形貌和光学性能进行表征,表征了制备的PVDF–OH@CQDs/PVAL复合薄膜的稳定性及紫外线屏蔽功能。结果表明,制得的直径约18 nm的CQDs纳米粒子可以在溶液中很好地分散;CQDs有很高的吸光度,制备的PVDF–OH@CQDs/PVAL复合膜可以完全屏蔽紫外光。     

高通量rGO微球@PVDF纳米纤维复合膜的制备及其油水分离性能研究

采用静电纺丝法制备了聚偏氟乙烯(PVDF)纳米纤维膜,并采用共混纺丝法和真空抽滤两种方式将还原氧化石墨烯微球(rGO)负载于其上,获得高通量rGO微球@PVDF纳米纤维复合油水分离膜。通过调整静电纺丝过程参数(如推注速率和电场强度等)和纺丝液配方,对PVDF纳米纤维膜结构进行优化,并采用不同的rGO微球负载量、负载方式、黏结剂含量来提高纳米纤维膜的表面粗糙度和疏水性。利用扫描电子显微镜和接触角测试对纤维膜的表面形貌和亲疏水性进行表征,并通过二氯甲烷-水体系进行油水分离实验,测试了不同配方下杂化膜的重力驱动油水分离性能。结果表明,当静电纺丝溶液中PVDF含量为14%时,以1 mL·h^-1的推注速率,在15 kV下制得的PVDF纳米纤维膜,并将1%PVDF溶液、3 mg rGO微球(与黏结剂中有效成分PVDF质量比为3∶1)和溶剂组成的铸膜液抽滤在膜表面,复合膜表面水接触角为130.9°,其油水分离过程中的有机溶剂透过通量可达5 641.3 L·h^-1·m^-2,水相的截留率为99.28%。     

铸膜液的粘度和组成对PVDF微孔膜性能的影响

实验采用浸没沉淀相转化的方法制备PVDF微孔膜,考察了聚偏氟乙烯(PVDF)/聚乙二醇(PEG-6000)/二甲基乙酰胺(DMAc)比例的变化,对铸膜液的粘度及膜性能的影响。分析了影响膜过程动力学因素,确定了该体系制膜的理想条件。结果表明,当PVDF质量分数为14%,PEG(6000)质量分数为5%时,制得的平板膜可达较佳性能。     

弱凝固剂对高疏水PES膜结构与耐润湿性能的影响

以聚醚砜(PES)/N,N-二甲基乙酰胺(DMAc)为铸膜液,以1000#的耐水砂纸作为制膜基底,制备了接触角为134°的PES高疏水膜。采用电子扫描电镜(SEM)和接触角仪表征了膜的结构和耐润湿性能。讨论了凝固浴中不同含量弱凝固剂(正丙醇)对PES成膜机理、膜结构和膜表面耐润湿性能的影响。随着凝固浴中弱凝固剂含量的增加,PES膜表面的接触角呈现增大的趋势。     

聚乙烯阴离子交换膜掺混聚偏氟乙烯改性表征

聚偏氟乙烯（PVDF）因含氟乙烯基单体,拥有良好的化学稳定性、热学稳定性和机械性能,与其他高分子膜材料相比更容易提高离子交换膜的性能。本实验采用热压法制备PVDF聚乙烯阴离子交换膜,探讨了PVDF含量对膜性能的影响,如膜电阻、离子交换容量、耐破度、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PVDF膜表面性质和结构进行了分析。结果表明,当PVDF含量增加时,膜面电阻、耐破度升高。离子交换容量、含水率,反离子选择透过性降低。虽然PVDF的添加导致含水率、交换容量等膜性能的下降,但耐破度的升高表明膜稳定性和机械性能得到了提升,这赋予PVDF聚乙烯膜一定的使用价值。     

聚偏氟乙烯／蒙皂石超滤膜的制备及性能研究

以聚偏氟乙烯(PVDF)为原料,无机层状材料蒙皂石(MMT)为添加剂,通过溶胶-凝胶相转化法研制成PVDF/MMT超滤膜.考察了MMT质量分数在0%~9%范围内对铸膜液黏度、膜孔隙率、孔径、水通量、PEG20000截留率等性能的影响,以及相图和DSC曲线的变化.实验结果表明,MMT的加入使铸膜液的黏度增加,铸膜液呈现非牛顿流体中的假塑性流体的特性;当MMT加入质量分数为7%时,PVDF/MMT超滤膜水通量可达94.32 L·m-2·h-1,对PEG20000的截留率达95.2%.MMT的添加对成膜过程也有影响,从相图分析,加入MMT改变了液–固双节点的位置,铸膜液对非溶剂的容纳能力降低;而从DSC测试曲线得知PVDF/MMT膜的结晶度低于PVDF膜.     

非溶剂相转化辅助粗糙基底法制备高疏水PES膜

以提高PES膜的疏水性能为目的,采用非溶剂相转化辅助模板法制备了高疏水的PES平板膜。讨论了非溶剂相转化辅助粗糙基底法对PES膜膜结构的影响,并分别研究了砂纸目数、铸膜液浓度、凝固浴中正丙醇浓度对PES膜的复制效果和疏水性的影响。实验表明,砂纸目数为1 000目,铸膜液中PES质量分数为15%,凝固浴中正丙醇含量为100%时,制备的PES膜的疏水性较高,接触角由80°上升至134°。     

聚偏氟乙烯共混膜的制备和性能研究

主要讨论了聚偏氟乙烯(PVDF)膜以及聚甲基丙烯酸甲酯(PVDF/PMMA)、PVDF/PMMA/PS(聚砜)共混膜的制备及性能,并研究了不同添加剂对PVDF/PMMA/PS共混膜的结构和性能的影响。实验数据表明:PVDF/PMMA/PS共混膜的通量最大;PVPK 40成膜通量最大;T iO 2成膜截留率最大。     

葡萄糖对聚偏氟乙烯膜性能的影响

用相转化法制备了聚偏氟乙烯/葡萄糖共混膜。当聚偏氟乙烯质量分数为10%,葡萄糖质量分数为4%时,膜的水通量和孔隙率最高,为33.1 mL/(cm2.h)和92.6%;接触角也由92°减小为72°,显示出很好的亲水性。并对共混膜的微观结构、XRD、红外光谱和热稳定性进行了详细的研究,讨论了聚偏氟乙烯和葡萄糖的共混机理。     

膜材料对膜曝气生物膜反应器性能影响的比较

选择聚偏氟乙烯(PVDF)和聚丙烯(PP)中空纤维曝气膜作为膜曝气生物膜反应器(MABR)的膜组件材料,比较两种膜材料由于亲疏水性能、表面形态、生物相容性等性质的差别,对MABR挂膜启动速度、生物附着量、脱氮除碳及膜污染等性能的影响。研究显示,运行末期PVDF和PP膜纤维生物附着量分别为35.62 g·m^-2和30.63 g·m^-2。通过场发射扫描电子显微镜观察两种膜表面生物污染情况,PVDF膜纤维表面呈鱼鳞状结构,有效保护了膜孔不被微生物完全堵塞。在90 d的运行周期内以PVDF为曝气膜材料的MABR获得了90%以上的COD去除率和78%的TN去除率;而以PP为曝气膜的MABR由于运行后期曝气膜纤维污染严重仅得到了76.5%的COD去除率和49.1%的TN去除率。因此,PVDF曝气纤维更适于作膜曝气生物膜反应器的曝气膜。     

The facile method developed for preparing polyvinylidene fluoride plasma separation membrane via macromolecular interaction

The design of membrane pore is critical for membrane preparation. Polyvinylidene fluoride (PVDF) membrane exhibits outstanding properties in the water-treatment field. However, it is a huge challenge to prepare PVDF macro-pore plasma separation membrane by non-solvent induced phase separation (NIPS). Herein, a facile strategy is proposed to prepare PVDF macro-pore plasma separation membrane via macromolecular interaction. ATR-FTIR and ¹H NMR showed that the intermolecular interaction existed between polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP). It could significantly affect the PVDF macro-pore membrane structure. The maximum pore of the PVDF membrane could be effectively adjusted from small-pore/medium-pore to macro-pore by changing the molecular weight of PEO. The PVDF macro-pore membrane was obtained successfully when PEO-200 k existed with PVP. It exhibited higher plasma separation properties than the currently used plasma separation membrane. Moreover, it had excellent hemocompatibility due to the similar plasma effect, hemolysis, prothrombin time, blood effect and complement C_3a effect with the current utilized plasma separation membrane, implying its great potential application. The proposed facile strategy in this work provides a new method to prepare PVDF macro-pore plasma separation membrane by NIPS.     

运行停抽时间对平板膜分离效果的影响

通过理论计算分析了PVDF截留分子量140000的平板膜和300目金属平板膜的最佳运行／停抽时间关系，并通过试验验证了理论计算结果。实验结果表明，对于平板膜存在最佳运行／停抽时间关系，但是在污泥浓度过高时，影响平板膜运行通量的主要因素已经不再是运行／停抽时间，而是累计抽吸时间．     

纳米氧化石墨烯改性PVDF微滤膜在MBR中的抗污染性能

利用强亲水性氧化石墨烯（GO）作为添加剂,自制了PVDF/GO复合微滤膜,并将其应用于MBR系统中,进行长期应用研究。研究发现,共混膜的表面性质得到改善,其表面含氧基团达到29.33%（GO=3%）;共混膜与PVDF膜对污染物的去除效果相近,但共混膜（GO=3%）仅进行了一次清洗,清洗周期是PVDF的4倍;PVDF/GO共混膜的膜阻力要低于PVDF膜,并且共混膜的不可逆污染阻力显著下降,其数值仅仅是PVDF膜的9.0%（GO=3%）;EPS分析发现,共混膜表面的EPS浓度明显减少,其降幅分别达到59.98%（GO=1%）和69.57%（GO=3%）,抗污染性能显著提高;通过SEM与CLSM分析发现,随着氧化石墨烯加入量的提高,共混膜表面形成了滤饼层变得疏松,厚度也变薄,甚至露出了部分膜表面（GO=3%）,保证了共混膜稳定的渗透率。     

Ozone Cleaning of Fouled Poly(Vinylidene) Fluoride/Carbon Nanotube Membranes

This research demonstrates for the first time that ozone is an effective cleaning agent for polyvinylidene fluoride (PVDF) membranes fouled by natural organic matter (NOM). Bare PVDF membranes as well as PVDF impregnated with CNTs (pristine (CNTs–P) and oxidized (CNTs–O)) at 0.3% mass membranes were used. Three different methods were investigated for cleaning the fouled membranes including; A: 10-min cleaning by pure water, B: 5-min water followed by 5-min ozonated water, and C: 10-min fully ozonated water. It was found that the application of fully ozonated water for 10 min was very effective to reinstate the flux to almost its original value of unfouled membrane. The CNTs–P/PVDF membrane exhibited the highest fouling with a total fouling ratio of 81%, while for the bare PVDF and the CNTs–O/PVDF membranes, the fouling ratios were 76% and 74%, respectively. The full ozonated water cleaning method gave the highest removal of fouling leaving the lowest irreversible fouling on the membrane as compared to the other cleaning methods. On the other hand, the highest removal of NOM fouling was obtained for CNTs–O/PVDF membranes indicating that fouling on CNTs–O/PVDF membrane was less bound than the other membranes. Contact angle measurements of the fouled membranes showed that all membranes exhibited increased contact angles due to the NOM deposition but after cleaning, particularly with ozonated water, the membrane contact angles returned to almost their original values. FTIR analysis of the membranes corroborated the results obtained.     

Fabrication of poly(vinylidene fluoride) membrane via thermally induced phase separation using ionic liquid as green diluent

Ionic liquid(IL), 1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6) as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF) membranes via thermally induced phase separation(TIPS). Phase diagram of PVDF/[BMIM]PF6 was measured. The effects of polymer concentration and quenching temperature on the morphologies, properties, and performances of the PVDF membranes were investigated. When the polymer concentration was 15 wt%, the pure water flux of the fabricated membrane was up to nearly 2000 L·m~(-2)·h~(-1), along with adequate mechanical strength. With the increasing of PVDF concentration and quenching temperature, mean pore size and water permeability of the membrane decreased. SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6) presented spherulite structure. And the PVDF membranes were represented as β phase by XRD and FTIR characterization. It provides a new way to prepare PVDF membranes with piezoelectric properties.     

表面沉积化镁合金基底上超疏水聚偏氟乙烯微孔膜的制备与性能

用一步浸泡法制得表面沉积化镁合金板，再以此镁合金板为制膜基底，以聚偏氟乙烯（PVDF）/N,N-二甲基乙酰胺（DMAc）/辛醇/水为制膜体系，采用干-湿相转化法制备了超疏水PVDF膜，该膜的水接触角可达160°。用粗糙度仪、扫描电镜、能谱仪、红外光谱仪等对镁合金表面和PVDF膜底面的微观结构、化学组成进行表征和分析。研究表明，一步浸泡处理过的镁合金表面生成了均匀的十四酸铁沉积物，该沉积物可在膜制备中部分嵌入膜底面，增加了膜底面的粗糙度，从而使PVDF膜的疏水性大幅提高。对PVDF膜的磨损试验表明，所制备的超疏水膜表面具备良好的机械稳定性。真空膜蒸馏实验表明，所制备的PVDF膜具有较高的通量和截留率，在运行中保持了更好的操作稳定性。     

High-flux PVDF/PVP nanocomposite ultrafiltration membrane incorporated with graphene oxide nanoribbones with improved antifouling properties

A novel polyvinylidene fluoride (PVDF) nanocomposite membrane containing graphene oxide nanoribbones (GONRs) as a new nanofiller and polyvinylpyrrolidone (PVP) as pore former agent was prepared via phase inversion method. GONRs were prepared by oxidative unzipping of multi-walled carbon nanotubes (MWCNTs) via chemical approach. Chemical vapor deposition method was used to synthesis MWCNTs. The effects of adding GONRs and PVP into the casting solution on morphology, hydrophilicity and pure water flux (PWF) of the prepared nanocomposite membranes were explored. Antifouling experiments were also performed. It was found that compared to the neat PVDF membrane, PWF of the PVDF/PVP, PVDF/(0.5GONRs) and PVDF/(0.5GONRs)/PVP membranes were improved 80%, 44.9%, and 241.6%, respectively. The obtained results showed that GONRs and PVP exhibit synergistic effects in controlling the membrane properties. This work shows that GONRs can be suitable as nanofiller for preparation of high performance PVDF ultrafiltration membranes with improved antifouling properties.