改性污泥炭/TiO2/PVP/PVDF超滤膜的制备及其性能测试

采用铁离子改性污泥炭(Fe₃O₄/SAC磁质炭)、二氧化钛(TiO₂)和聚乙烯吡咯烷酮(PVP)为添加剂进行聚偏氟乙烯(PVDF)膜的改性，并对共混膜的各项性能进行测试和表征。结果表明，当TiO₂和Fe₃O₄/SAC磁质炭质量分数分别为0.15%、0.2%时，膜的综合性能最佳。此时，接触角为48.5°,纯水通量为124 3.43 L/(m²·h),牛血清蛋白截留率为95.21%。     

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。     

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。     

两种支撑材料对PVDF膜微观结构和性能的影响

选用2种无纺布(W₁、W₂)作为膜支撑材料，通过非溶剂致相分离(Nips)法制备聚偏氟乙烯(PVDF)平板膜，利用扫描电子显微镜、接触角测试仪对无纺布和膜的形貌和亲水性进行分析，分析支撑材料的表面形貌和亲水性对PVDF膜微观结构、抗污染、水通量和剥离强度的影响。结果表明，W₂的纤维直径较大，呈三维排列的网络几何结构，纤维间的结合更紧密。与W₁相比，W₂接触角增大至96°,虽然支撑材料的亲水性降低，但是，以W₂为支撑材料制备的PVDF膜综合性能最佳，纯水通量为910 L/(m²·h),通量恢复率为98.4%,无纺布与膜的剥离强度为244 N/m。在相同刮膜条件下，以W₁为支撑材料制备的膜纯水通量为230 L/(m²·h),通量恢复率为80.6%,剥离强度为160 N/m。因此，将密度小、质量大的无纺布(W₂)作为支撑材料，能提高PVDF平板膜的综合性能。     

IL/GO/PVP/PVDF改性膜处理重金属离子的研究

将离子液体（IL）1-乙基-3-甲基咪■六氟磷酸盐（[EMIM]PF₆）、氧化石墨烯（GO）、聚乙烯吡咯烷酮K30（PVP）、聚偏氟乙烯（PVDF）、二甲基甲酰胺（DMF）共混制备IL/GO/PVP/PVDF改性超滤膜。以IL/GO复合添加剂为变量,测试了膜对Cd²⁺、Pb²⁺、Hg²⁺ 3种重金属离子的截留率和抗污染率,并探究了离子浓度和pH对膜截留性能的影响。结果表明,IL/GO的添加降低了超滤膜接触角,有效提高了膜表面的亲水性。当IL/GO复合添加剂质量分数为4%/0.6%时膜的综合性能最佳,对Cd²⁺、Pb²⁺、Hg²⁺的截留率可达96.31%、97.72%、96.47%,受污染后通量恢复率为79.24%、85.70%、82.28%。     

脱乙酰基改性乙酸纤维薄膜对乳化油分离及积垢机理的探究

利用静电纺丝制造乙酸纤维素膜（CA纤维膜）,并利用添加TiO₂及脱乙酰基（d-CA）对CA纤维膜进行改性,后续对膜过滤特性、渗透通量、油水乳化液去除效率、反洗特性及积垢机制进行讨究。结果显示,CA纤维膜通过TiO₂及d-CA改性后可以提高膜的热稳定性及亲水性能,并得到稳定的纯水通量和过滤通量;最佳的比例为TiO₂@d-18.5%CA纤维膜,在40kPa跨膜压差、60min的操作条件下,其纯水通量、过滤通量、1g/L油水乳化液去除效率以及反洗后通量分别为824.8L/(m²·h)、(311.3±12.5)L/(m²·h)、93.6%±1.1%、451.5L/(m²·h);另外,添加TiO₂可能导致油水乳化液在膜表面不可逆阻力比例的增加,脱乙酰基改性CA纤维膜则可以降低膜自身阻力及增加可逆阻力的比例,提高CA纤维膜在油水分离方面的潜力。     

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...     

聚偏氟乙烯纳滤膜制备及其处理模拟活性黑废水

为研制适用于染料废水处理的新型纳滤膜,以自制的PVDF膜为基膜,通过溶胶-凝胶方法在膜表面涂覆TiO₂纳米颗粒层,然后再涂敷多巴胺/PEI层,以制备PVDF纳滤膜。考察了制备条件对膜的表面特性及过滤性能的影响。结果表明,TiO₂和多巴胺/PEI可以顺序的涂覆在PVDF膜表面。表面涂覆后,膜的通量急剧下降,截留率大幅度上升。随着涂覆时间的增加,膜的亲水性增加,膜表面孔径增大,膜的通量回升,截留率减小。涂覆时间为6、12、24 h时,PVDF膜对PEG2000的截留率分别为92%、75%、56%,对活性黑5(RB5)截留率分别为83%、62%和44%。表明涂覆时间为6 h时,PVDF膜达到纳滤膜级别,此时膜对PEG2000、RB5溶液的稳定通量分别为210、105 L/(m²·h)。     

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。     

TiO2/GO/EP复合涂层的光电化学防腐蚀性能研究

通过水热法合成TiO₂/GO复合纳米材料，在Q235碳钢表面制备了一系列TiO₂/GO/EP复合涂层，并对复合材料进行结构表征，探究不同含量GO对复合涂层光电化学防腐性能的影响。结果表明：TiO₂/GO纳米复合材料在紫外光和可见光区域吸收强度有明显提升；不同配比的TiO₂/GO/EP复合涂层都具有光电响应和光致阴极保护效果，其中，TiO₂/GO/EP-3复合涂层的光电响应最明显，光电流密度为0.003 8 A/cm²，光电压降至-681 mV。在环氧树脂中添加纳米复合粒子后涂层的耐水性、耐碱性更优，耐酸性有所改善，硬度和附着力明显增大，可对Q235碳钢基体提供良好的涂层屏蔽保护和半导体光生阴极保护作用。     

Effect of additives concentration on the surface properties and performance of PVDF ultrafiltration membranes for refinery produced wastewater treatment

The aim of this study was to investigate the effect of pore-forming hydrophilic additives on the porous asymmetric polyvinylideneflouride (PVDF) ultrafiltration (UF) membrane morphology and transport properties for refinery produced wastewater treatment. PVDF ultrafiltration membranes were prepared via a phase inversion method by dispersing lithium chloride monohydrate (LiCl·H₂O) and titanium dioxide (TiO₂) nanoparticles in the spinning dope. The morphological and performance tests were conducted on PVDF ultrafiltration membranes prepared from a different additive content. The top surface and cross-sectional area of the membranes were observed using a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The surface wettability of porous membranes was determined by the measurement of a contact angle. The mean pore size and surface porosity were calculated based on the permeate flux. The results indicated that the PVDF/LiCl/TiO₂ membranes with lower TiO₂ nanoparticles loading possessed smaller mean pore size, more apertures inside the membrane with enhanced membrane hydrophilicity. LiCl·H₂O has been employed particularly to reduce the thermodynamic miscibility of dope which resulted in increasing the rate of liquid–liquid demixing process. The maximum flux and rejection of refinery wastewater using PVDF ultrafiltration membrane achieved were 82.50 L/m² h and 98.83% respectively at 1.95 wt.% TiO₂ concentration.     

Development of mesoporous titanium dioxide hybrid poly(vinylidene fluoride) ultrafiltration membranes with photocatalytic properties

A photocatalytic activity ultrafiltration membrane (UFM) was prepared by the blending of a poly(vinylidene fluoride) (PVDF) polymer with mesoporous titanium dioxide (M‐TiO₂) particles via the phase‐inversion method. The microstructure of the membrane and Ti element distribution were characterized by scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. Their properties were also determined by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, tensile stress tests, contact angle tests, bovine serum albumin retention, water flux, and permeation flux. When the M‐TiO₂ concentration reached 1 wt %, the thermal stability, mechanical properties, hydrophilicity, flux, and antifouling performance of the M‐TiO₂/PVDF UFM were improved to an optimal value with the M‐TiO₂ particles successfully entrapped and evenly distributed throughout the PVDF polymer matrix. Compared with the P25‐modified PVDF UFM (1 wt %), the M‐TiO₂‐modified PVDF UFM (1 wt %) exhibited better photocatalytic activity and wonderful stability in the UV photocatalytic degradation of the organic dye Rhodamine B. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43427.     

Structural and performance properties of UV-assisted TiO2 deposited nano-composite PVDF/SPES membranes

In this research, the surface of poly (vinylidene fluoride) (PVDF)/sulfonated polyethersulfone (SPES) blend membrane prepared via immersion precipitation was modified by depositing of TiO₂ nano-particles followed by UV irradiation to activate their photocatalytic property. The membranes were characterized by FTIR, SEM, AFM, contact angle, dead end filtration (pure water flux and BSA solution flux), antifouling analysis and antibacterial activity. The FTIR spectrum confirmed the presence of OH functional groups on the PVDF/SPES membrane structure, which was the key factor for deposition, and self-assembly of TiO₂ nanoparticles on the membrane surface. The SEM and AFM images indicated that the TiO₂ nanoparticles were deposited on the PVDF/SPES membrane. The contact angle measurements showed that the hydrophilicity of PVDF/SPES membrane was strongly improved by TiO₂ deposition and UV irradiation. The filtration results indicated that the initial flux of TiO₂ deposited PVDF/SPES membranes was lower than the initial flux of neat PVDF/SPES membrane. However, the former membranes showed lower flux decline compared to the neat PVDF/SPES membrane. The BSA rejection of modified membranes was improved. The fouling analysis demonstrated that the TiO₂ deposited PVDF/SPES membranes showed the fewer tendencies to fouling. The results of antibacterial study showed that the UV irradiated TiO₂ deposited PVDF/SPES membranes possess high antibacterial property.     

Nano SiO2 and TiO2 embedded polyacrylonitrile/polyvinylidene fluoride ultrafiltration membranes: Improvement in flux and antifouling properties

Polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) ultrafiltration (UF) membranes are widely used in drinking water and wastewater applications. These membranes are prone to fouling and membrane efficiency decreases with time under constant operation. Significant improvements/modifications are necessary to apply these polymers as sustainable membrane materials. In this study, PVDF and PAN UF membranes were modified through incorporation of nanoparticles (NPs) namely SiO₂ and TiO₂. PVDF and PAN UF membranes were prepared by phase inversion method from polymer solutions having dispersed SiO₂ and TiO₂ NPs in it. Membrane surface hydrophilicity, charge, roughness, and morphology were studied. Equilibrium water content and molecular weight cut-off of the membranes were also measured. Addition of NPs increased membrane surface hydrophilicity, equilibrium water content, and surface potential. NPs modified membranes exhibited better membrane flux (35–79% higher) and antifouling properties (flux recovery ratio values 28–41% higher) than the virgin membranes.     

氧化石墨烯改性PVDF超滤膜制备及分离性能

用N-（三甲氧基硅丙基）乙二胺三乙酸钠（EDTS）对氧化石墨烯进行修饰,制备出亲水的EDTS-GO纳米复合物。然后通过共混的方式将EDTS-GO添加到PVDF中,制备出EDTS-GO改性PVDF超滤膜。接触角分析和红外光谱结果表明,在相转化过程中EDTS-GO转移至膜表面,PVDF膜表面的亲水性增强。系统考察了不同EDTS-GO添加量对膜性能的影响。膜性能测试表明,随着EDTS-GO添加量的增加,PVDF膜的纯水通量先增大然后降低,当添加量为0.5%时,纯水通量达到最大值,711.2 L·（m²·h）^-1。此外,抗污染实验表明,EDTS-GO改性的PVDF超滤膜比未改性的PVDF超滤膜具有更强的抗污染性能。     

Studies on the surface properties of mixed‐matrix membrane and its antifouling properties for humic acid removal

A major factor limiting the use of ultrafiltration (UF) membrane in water treatment process is the membrane fouling by natural organic matter such as humic acid (HA). In this work, neat PVDF and PVDF/TiO₂ mixed‐matrix membranes were prepared and compared in terms of their antifouling properties. Two commercial types of TiO₂ namely PC‐20 and P25 were embedded to prepare the mixed matrix membranes via in situ colloidal precipitation method. The contact angles for the mixed‐matrix membranes were slightly reduced while the zeta potential was increased (more negatively charged) compared with the neat membrane. Filtration of HA with the presence of Ca²⁺ demonstrated that mixed‐matrix membrane could significantly mitigate the fouling tendency compared with the neat membrane with flux ratio (J/J₀) of 0.65, 0.70, and 0.82 for neat PVDF membrane, PVDF/TiO₂ mixed‐matrix membrane embedded with P25 and PC‐20, respectively. PC‐20 with higher anatase polymorphs exhibited better antifouling properties due to its hydrophilicity nature. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and antifouling performance of thin inorganic ultrafiltration membrane via assisted sol-gel method with different composition of dual additives

A novel TiO₂ thin film was prepared on the ceramic hollow fiber by the sol-gel method using poly(vinylpyrrolidone) (PVP) and polyvinyl alcohol (PVA) as additives. SEM images verified the formation of TiO₂ layer with various thickness using different composition of titania sols. The effect of the PVP and PVA contents on the TiO₂ sol properties, the separation and the antifouling performance of the ultrafiltration membranes were investigated thoroughly. When the contents of PVP and PVA were 1.0 wt% and 0.8 wt%, respectively, the resultant membrane showed a thickness of 0.55 μm with a pure water flux of 255 L m^?2 h^?1. In addition, the adherent foulant bovine serum albumin was applied to evaluate the antifouling performance. During the three fouling-recovery cycles, the flux recovery ratio and the flux decay ratio maintained about 99% and 30%. The BSA flux and rejection were still 169 L m^?2 h^?1 and 96.9% after the cycles, indicating a superior antifouling property.     

Fabrication of an antifouling GO-TiO2/PES ultrafiltration membrane

PES ultrafiltration membrane is widely used in various fields due to its high-filtration efficiency. However, due to its hydrophobicity, PES ultrafiltration membrane has poor antifouling performance, this reduced service life and increased industrial cost. Blending is a common method in ultrafiltration membrane hydrophilic modification. Adding a small amount of inorganic nanoparticles into the polymer membrane can improve the properties of the polymer membrane. However, nanoparticles are not uniformly dispersed in polymer membrane, which hindering the modification ability of nanoparticles to ultrafiltration membrane. In this paper, GO-TiO₂ materials were prepared by hydrothermal method, and GO-TiO₂/PES blended ultrafiltration membranes were fabricated by nonsolvent induced phase separation (NIPs). The experimental results show that GO-TiO₂ disperse uniformly in GO-TiO₂/PES ultrafiltration membrane, which greatly improved the antifouling performance of the membrane. When the addition amount of GO-TiO₂ is 0.6%, the water flux of membrane reaches 194.5 (L m⁻² h⁻¹), and the rejection rate of BSA reaches 89.4%. After three pollutions-cycles, the flux recovery rate of the membrane is 90.2%.     

PVDF/TiO2/graphene oxide composite nanofiber membranes serving as separators in lithium-ion batteries

Improving the electrochemical properties of membranes in lithium-ion batteries (LIBs) is very important. Many attempts have been made to optimize ionic conductivity of membranes. The aim of this study was fabricating composite nanofiber membranes of poly(vinylidene fluoride) (PVDF), containing titanium dioxide (TiO₂) and graphene oxide (GO) nanoparticles to use in LIBs as separators. The morphology, crystallinity, porosity, pore size, electrolyte uptake, ionic conductivity, and electrochemical stability of the membranes were investigated using scanning electron microscopy, wide-angle X-ray diffraction, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and linear sweep voltammetry. The electrolyte uptake and ionic conductivity of the PVDF/TiO₂/GO composite nanofiber membranes containing 2 wt % GO were 494% and 4.87 mS cm⁻¹, respectively, which were higher than those of the other fabricated membranes as well as the commercial Celgard membrane. This could be attributed to the increased porosity, larger surface area, and higher amorphous regions of the PVDF/TiO₂/GO composite nanofiber membranes as a result of the synergistic effects of the nanoparticles. In this work, suitable optimized membranes with greater electrochemical stability compared with the other membranes were presented. Also, it was demonstrated that the incorporation of the TiO₂ and GO nanoparticles into the PVDF nanofiber membranes led to a porous structure where the electrolyte uptake enhanced. These properties made these membranes promising candidates for being used as separators in LIBs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48775.     

Fabrication of antifouling membranes by blending poly(vinylidene fluoride) with cationic polyionic liquid

Membrane fouling problem is now limiting the rapid development of membrane technology. A newly synthesized cationic polyionic liquid (PIL) [P(PEGMA-co-BVIm-Br)] was blended with poly(vinylidene fluoride) (PVDF) to prepare antifouling PVDF membranes. The PVDF/P(PEGMA-co-BVIm-Br) exhibited an increased surface hydrophilicity, the water contact angle was reduced from 77.8° (pristine PVDF) to 57.9°. More porous membrane structure was obtained by adding PIL into the blending polymers, as high as 478.0 L/m²·h of pure water flux was detected for the blend PVDF membrane in comparison with pristine PVDF (17.2 L/m²·h). Blending of the cationic PIL with PVDF gave a more positive surface charge than pristine PVDF membrane. Blend membranes showed very high rejection rate (99.1%) and flux recovery rate (FRR, 83.0%) to the positive bovine serum albumin (BSA), due to the electrostatic repulsion between the membrane surface and proteins. After three repeated filtration cycles of positive BSA, the blend PVDF membranes demonstrated excellent antifouling performance, the permeation flux of the membranes was recovered very well after a simple deionized water washing, and as high as 70% of FRR was obtained, the water flux was maintained at above 350 L/m²·h. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48878.