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。     

共混β-环糊精改性PVDF膜的制备及性能

以N,N-二甲基乙酰胺(DMAc)为溶剂、聚乙二醇20000 (PEG 20000)和聚乙烯吡咯烷酮K30 (PVP K30)为致孔剂,以β-环糊精(β-CD)为添加剂进行共混改性,采用非溶剂致相分离法(NIPS)制备了β-CD共混改性聚偏氟乙烯(PVDF)膜。考察了β-CD添加量对改性膜微观形貌、渗透性能和截留性能、亲水性和抗污染性能的影响。结果表明,添加β-CD后改性膜表面开孔数量及孔径增加,膜截面皮层变薄,亚层发展出小指状孔,贯通的大指状孔数量降低,指状孔壁上出现更为疏松的大孔结构。添加β-CD后改性PVDF膜的纯水通量和牛血清蛋白(BSA)截留率均大幅提高,其中β-CD添加量为4%时改性膜的综合性能最佳,其纯水通量为1 848 L/(m²·h·bar),BSA截留率为90.43%。添加β-CD后改性膜动态水接触角下降为0°的时间减少,说明其内在湿润性增强。改性膜在渗透性能和分离性能提高的同时保持了较好的抗污染性能,所有膜的通量恢复率均达到98%以上。     

原位合成法制备高通量聚砜超滤膜及其性能研究

以聚砜（PSF）为原料,N,N‐二甲基甲酰胺（DMF）为溶剂,4,4'-二氨基二苯砜（DDS）和均苯四甲酸二酐（PMDA）为添加物,在聚砜铸膜液中“原位合成”聚酰胺酸（PAA）,采用浸没沉淀相转化法制备高水通量PSF超滤膜。使用傅里叶变换红外光谱仪（ATR-FTIR）和X射线光电子能谱分析（XPS）对膜表面化学组成进行分析,结果表明成功在膜表面引入PAA。膜的荷电性、水接触角、保湿性和水通量等性能测试表明,改性膜具有良好的保湿性和水渗透性。在0.1 MPa的运行压力下,改性膜的纯水通量和牛血清白蛋白（BSA）截留率均高于纯PSF超滤膜,纯水通量从221.39 L/(m²·h)增加至406.57 L/(m²·h),截留率从75.75%增加到96.14%;在0.01~0.1 MPa的运行压力范围内,改性膜水通量均高于纯PSF超滤膜。。     

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。     

亲水化改性PVDF超滤膜的抗污染特性研究

以不同通量的自制亲水化纳米SiO2改性PVDF超滤膜(PS)和聚乙烯醇改性PVDF超滤膜(PA),对城市污水二级出水(EfOM)和牛血清蛋白(BSA)水溶液进行了过滤试验,通过对比未添加改性剂的PVDF超滤膜,考察通量衰减率、膜污染阻力构成、通量恢复率等指标,分析水质与膜材料间的相互关系对超滤膜抗污染能力的影响.结果表明,在BSA料液中,3种通量下,低通量的膜抗污染能力好于高通量膜.20 min内PA膜表现出最低的膜通量衰减,而P膜在过滤初期通量就急剧下降.在EfOM料液中,各通量下,P膜通量衰减严重且产生了不可逆的堵孔阻力,亲水化改性后膜通量衰减率降低,稳态通量高,膜污染阻力主要来自于浓差极化和滤饼层阻力,其中PS膜通量下降率最低,而PA膜清洗后通量易恢复.     

丝瓜络纤维对PVDF超滤膜结构和性能的影响

以天然高聚物丝瓜络纤维作为亲水化改性剂,制备了不同丝瓜络纤维含量的亲水化超滤膜,对比分析PVDF基膜和改性膜过滤腐殖酸和海藻酸钠2种典型污染物配制的模拟废水时通量变化规律;考察了不同丝瓜络纤维含量对改性膜孔隙率、亲疏水性、纯水通量、截留率和抗污染性能的影响,利用扫描电镜(SEM)观察了膜微形貌结构。结果表明,丝瓜络纤维的质量分数为1.2%时,滤膜亲水性改善,PVDF质量分数分别为14%和16%的纯水通量较基膜分别提高3倍和3.5倍,截留率均保持93%以上,膜物理清洗后通量恢复率最高达94.2%。过滤模拟废水时,改性膜比通量衰减幅度较小,膜稳态通量高,抗污染性能好。     

PVDF/HTLcs超滤膜的制备及性能研究

用氧化镁脱硫废渣制备了类水滑石(HTLcs),将其与聚偏氟乙烯(PVDF)共混,采用相转换法制备HTLcs杂化PVDF超滤膜。考察了HTLcs对PVDF杂化膜表面形态、晶体结构、力学性能、热稳定性、渗透性能及抗污性能的影响。结果表明,杂化膜显示了更好的亲水性能和抗污性能,有较高的纯水通量和截留率,HTLcs的添加量为3%时,杂化膜得到最大的纯水通量243.67 L/(m~2·h),且具有较好的抗污性能,其恢复率最高达97.3%。     

多巴胺及KH-561改性PVDF超滤膜的制备及性能

采用聚多巴胺与亲水物质前驱体同步水解的方法,在膜表面生成杂化涂层,通过调整3-(2,3-环氧丙氧基)丙基三乙氧基硅烷(KH-561)与多巴胺的配比,制备了PVDF超滤改性膜。测试了杂化涂层对改性膜的表面形貌、亲水性、纯水通量、截留率等性能的影响。结果表明,杂化涂层不仅提高了改性膜的表面亲水能力,也改善了膜内部孔道的亲水性,PVDF改性膜的水接触角降至37.8°。膜水通量达到174 L/(m²·h),蛋白截留率达90%以上。杂化涂层在膜表面形成一层水膜,使膜具有良好的抗污染性能,改性膜的衰减系数最低可达0.19。     

介孔Al_2O_3/PVDF复合中空纤维膜的制备及其性能

为了提高PVDF中空纤维膜在处理含油废水过程中的亲水性能、抗压实性能和抗污染性能,实验以介孔Al2O3为无机添加粒子,采用溶液纺丝法制备出介孔Al2O3/PVDF复合中空纤维膜。通过扫描电子显微镜和傅里叶红外光谱观察介孔Al2O3/PVDF复合中空纤维膜的形貌和成分,结果证明介孔Al2O3成功地添加到PVDF中空纤维膜中。通过接触角,纯水和含油废水通量的测试,结果表明介孔Al2O3的添加改善了PVDF膜的亲水性能、抗压实性能和抗污染性能。     

MOF-199@GO改性PVDF荷电纳滤膜的制备及其性能

采用原位生长法制备了MOF-199@氧化石墨烯（GO）纳米复合材料，并对聚偏氟乙烯（PVDF）支撑膜进行表面改性，以克服PVDF膜表面疏水性。通过界面聚合反应，制备了基于MOF-199@GO改性PVDF的聚酰胺复合荷电纳滤膜。采用XRD、SEM、TEM、AFM和zeta电位等手段表征了MOF-199@GO复合材料及MOF-199@GO改性PVDF聚酰胺复合纳滤膜的结构及微观形貌，并测试了MOF-199@GO改性PVDF聚酰胺复合纳滤膜的脱盐性能。结果表明：通过MOF-199@GO复合材料对PVDF支撑膜的表面改性，有效克服了PVDF支撑膜的疏水性，实现了表面聚酰胺薄层的均匀连续生长，荷电纳滤膜表面荷负电性能显著增强，其中经MOF-199@GO充分改性的复合荷电纳滤膜表现出优异的脱盐性能，对MgSO₄、Na₂SO₄、NaCl和MgCl₂四种盐的截留率分别达到了93.56%、93.04%、87.48%和87.11%。     

Ag3PO4改性PVDF超滤膜的结构与性能

将不同量Ag₃PO₄均匀地分散在聚偏氟乙烯(PVDF)铸膜液中, 利用相转化法制备了改性PVDF膜, 通过扫描电镜(SEM)、接触角测定、过滤实验和污染性测试等研究了其微结构、分离性和耐污染性等, 并考察了膜污染后的清洗效果。结果表明, 添加Ag₃PO₄ 的PVDF膜具有不同的微结构与性能, 当添加1% 的Ag₃PO₄时, 膜皮层变薄、微孔数增多, 并呈现出最优化的水通量、亲水性、力学性、抗污染能力和截留率等。采用太阳光-水清洗能使改性膜的通量恢复率达到85%以上。     

PVDF/PEK-C共混膜的研究

实验以相转化法制备了PVDF/PEK-C共混膜,考察了共混体系的相容性及PEK-C的添加量对共混膜超滤性能、抗污染性能、稳定性等的影响。研究结果表明PVDF/PEK-C属于部分相容体系;添加适量PEK-C能够改善PVDF膜的超滤性能和抗污染能力;PVDF/PEK-C共混膜和纯PVDF膜具有相似的化学稳定性,与纯PVDF膜相比,共混膜具有较好的耐酸性,纯PVDF膜的耐氧化性则要优于共混膜。     

界面增强型PVDF/PET膜的制备及性能

通过对支撑材料进行表面改性处理和浸入凝胶法制备了界面增强型聚偏氟乙烯/聚对苯二甲酸乙二醇酯（PVDF/PET）超滤膜。用电导率在线测量法确定了硅烷偶联剂 3-氨丙基三乙氧基硅烷（KH550）水解液的制备条件,考察了改性处理条件对PVDF/PET膜的界面性能和力学性能的影响。通过180°剥离试验测试PVDF膜与支撑层间的剥离强度,用扫描电镜观察PET无纺布及PVDF膜破坏底面的微观形貌,用傅里叶红外光谱仪表征PET表面化学组成。结果表明,水解液中KH550用量较少时（≤3%）,处理时间延长,PVDF/PET间的剥离强度增大,水解液中KH550用量较多时（>3%）,处理时间延长,PVDF/PET间的剥离强度先增大后减小;PVDF/PET膜的拉伸强度随水解液中KH550用量的增加或处理时间的延长先增大后略减小。改性前后PVDF/PET膜的分离与透过性能对比表明,PET表面改性后,PVDF膜的牛血清白蛋白（BSA）截留率几乎不受影响,水通量略增。     

处理油库污水的改性PVDF超滤膜结构与性能

在PVDF/PVP体系中添加Al₂O₃和TiO₂两种无机纳米颗粒,利用沉浸凝胶相转化法制得纳米颗粒总量不同和比例不同的改性PVDF平板超滤膜。探讨了纳米颗粒比例和总量对膜性能的影响。利用SEM、XRD对改性膜的结构进行了表征。并利用该改性膜处理典型沿海油库含油污水。结果显示:两种无机纳米颗粒的加入,明显增强了纳米改性膜的亲水性,使膜的抗污染性能得到提高;膜的韧性和强度得到改进;膜表面及膜孔的微观结构、改性膜的结晶度没有受到无机纳米颗粒的明显影响。最佳的纳米颗粒总含量为3%,两种纳米颗粒最佳质量比例为1:2。采用改性膜处理油库含油污水,稳定时出水中悬浮物含量低于0.4 mg·L^-1;石油烃类含量低于0.5 mg·L^-1;COD值在60～70 mg·L^-1之间,达到了国家污水排放标准。     

氧化铝凝胶改性聚偏氟乙烯超滤膜的制备与表征

为提高聚偏氟乙烯超滤膜的亲水性,采用Al_2O_3凝胶对有机高分子聚偏氟乙烯膜进行改性,制备Al_2O_3凝胶改性聚偏氟乙烯超滤膜,并与非凝胶化无机纳米Al_2O_3颗粒改性进行对比。考察铸膜液中Al_2O_3凝胶加入量对改性聚偏氟乙烯超滤膜性能和结构的影响。采用扫描电镜、X射线能谱、傅里叶红外光谱和超滤实验等对超滤膜结构和性能进行表征,结果表明,Al_2O_3凝胶加入量1.0 g时,改性超滤膜水通量提高5.48倍;扫描电镜表明,改性超滤膜和未改性超滤膜均为典型的非对称结构,改性超滤膜表面孔数目明显增加,断面微观结构未发生改变;红外光谱及能谱分析表明,Al_2O_3凝胶与高分子聚偏氟乙烯之间为物理共混。Al_2O_3凝胶改性聚偏氟乙烯超滤膜,改善了膜表面亲水性,提高水通量,并保持较大截留率。     

Preparation and properties of MOF-199@GO modified PVDF charged composite nanofiltration membrane

As novel functional materials, metal-organic framework (MOF) and graphene oxide (GO) have received great attentions in recent years. In this work, MOF@GO nanocomposite (MOF-199@GO) is prepared by an in-situ growth method. A novel and highly efficient nanofiltration (NF) membrane can be facilely fabricated via surface decoration of MOF-199@GO onto poly(vinylidene fluoride) (PVDF) substrate before interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) in order to overcome the hydrophobicity of PVDF membrane. The structure and morphology of MOF-199@GO and MOF-199@GO modified PVDF polyamide composite membrane are characterized by XRD, SEM, TEM, AFM and zeta potential. MOF-199@GO modified PVDF composite NF membrane which possesses dense and uniform polyamide thin-layer exhibits higher negative surface potential (up to ~37 mV) at pH 9.5. The performance of MOF-199@GO modified PVDF polyamide composite NF membrane has been investigated by determination of pure water flux and salt rejection. The prepared NF membrane MG3 exhibited highly efficient rejection of MgSO₄, Na₂SO₄, NaCl and MgCl₂, which are 93.56%, 93.04%, 87.48% and 87.11%, respectively. This work provides a worthy reference for designing highly efficient NF membranes modified by MOF and relevant materials.     

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.     

平板式超声对污染聚偏氟乙烯中空纤维超滤膜清洗

Polyvinylidenefluoride （PVDF） hollow fiber ultrafiltration membrane is frequently employed in water treatment. However, the fouling of ultrafiltration membranes affects the economic effectiveness of such process significantly. The ultrasound generated by flat plate transducer （UFPT） was used to clean the polluted PVDF ultrafiltration membrane with 2 g·L^-1 of citric acid aqueous solution in our study. The effects of UFPT intensity on the membrane surface were studied. The new membrane was easy to be polluted by the saturated CaCl2 solution. A synergistic effect of UFPT and 2 g·L^-1 citric acid aqueous solution could remove the foul of the membrane, and its flux could be recovered about 81%. The flux recovery of old membrane polluted was increased to 73.2% after 7 h soaking in citric acid aqueous solution, but its flux recovery without soaking was only increased to 56.2%.     

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.