ZIF-67/PEBA杂化膜分离水中乙酸乙酯

为了提升从水溶液中回收乙酸乙酯的渗透汽化分离效率,将疏水ZIF-67颗粒填充到聚醚共聚酰胺(PEBA)中,制备得到ZIF-67/PEBA杂化膜。通过扫描电镜(SEM)、能谱(EDS)、接触角测量、傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、热重(TGA)和溶胀度测试等手段对ZIF-67和杂化膜的物理化学性质进行表征,通过渗透汽化实验考察ZIF-67质量分数、进料质量分数和温度对膜分离性能的影响。结果表明ZIF-67与PEBA基质之间为物理共混,杂化膜疏水性增强。随着ZIF-67质量分数的增加,总渗透通量先降低后升高,分离因子先升高后降低,当ZIF-67质量分数为5%时分离因子最高;随着进料质量分数或温度增加,总渗透通量和分离因子均增加,最大总渗透通量为2299g·m~(-2)·h~(-1),最大分离因子为122。研究为渗透汽化技术工业化应用提供了必要的基础数据和理论依据。     

硬脂酸改性γ-Al_2O_3填充PEBAX膜渗透汽化分离苯胺

利用硬脂酸对纳米γ-Al_2O_3改性,分别制备了聚醚共聚酰胺(PEBAX)均质膜、填充膜、复合膜以及填充型复合膜四种分离膜,探讨了膜在苯胺/正庚烷体系中的溶胀性能和渗透汽化性能。利用FT-IR、XRD分别考察了改性前后γ-Al_2O_3颗粒官能团和晶体结构的变化情况,通过SEM观察膜的形貌结构。溶胀实验结果表明:随着料液中苯胺浓度和料液温度的升高,溶胀度均持续增大,在48 h时达到溶胀平衡,填充量为2%(wt)时填充膜的溶胀效果最好;渗透汽化实验结果表明:膜的渗透通量和分离因子均随料液中苯胺浓度和料液温度的升高而持续增大,填充型复合膜的综合性能最优,其填充量为2%(wt)时分离性能最佳,当苯胺浓度为5000μg×g~(-1)、温度为70℃时,膜的渗透总通量为5.64 kg×m~(-2)×h~(-1),分离因子为3.07。     

SiO_2-PEBAX/PAN膜渗透汽化分离吡啶

以聚醚共聚酰胺(PEBAX)为分离膜材料,聚内烯腈(PAN)超滤膜为支撑层,纳米气相二氧化硅(n-Si O2)颗粒为填充物,分别制备了PEBAX/PAN复合膜及n-Si O2-PEBAX/PAN填充型复合膜,旨在通过渗透汽化分离吡啶。采用扫描电镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)对复合膜进行表征,表明n-Si O2与聚合物只是物理混合。以吡啶/正庚烷混合物为模拟溶液,考察膜的溶胀及渗透汽化分离性能。溶胀实验结果表明:膜溶胀度随料液吡啶含量及温度的增加而增大。渗透汽化实验结果表明:n-Si O2填充量为10‰(wt)时总渗透通量最大,填充量为5‰(wt)时分离因子最大。总渗透通量和分离因子都随料液吡啶浓度增大而增加;渗透汽化操作温度升高,总渗透通量增大,而分离因子减小。当填充量为5‰(wt)、温度为30℃、以及料液吡啶含量为5000?g?g?1时,Pn5膜的总渗透通量为5.05 kg?m?2?h?1,分离因子为3.39。研究结果表明,Si O2-PEBAX/PAN复合膜对吡啶有较好的富集作用。     

Silicalite-1/PAAS杂化膜的二甲苯异构体渗透汽化分离研究

Silicalite-1经3-氨丙基-三乙氧基硅烷(APTES)改性后,通过共混制备silicalite-l/聚丙烯酸钠(PAAS)杂化膜,用于二甲苯异构体的渗透汽化分离.膜的SEM分析表明,改性后silicalite-1与PAAS之间的相容性有较大改善.溶胀和渗透汽化实验发现:(1)对、邻二甲苯在杂化膜中的平衡溶胀量...     

CTAB改性膨润土填充PEBAX/PVDF膜渗透汽化降低汽油噻吩含量

用十六烷基三甲基溴化铵(CTAB)对膨润土进行柱撑改性,并对改性前后的膨润土进行吸附实验及红外测定。将改性后膨润土置于填充聚醚共聚乙酰胺(PEBAX)聚合物溶液中,以聚偏氟乙烯(PVDF)超滤膜为支撑膜,制备复合膜,考察复合膜在模拟汽油(噻吩/正庚烷)中的溶胀性能,并进行渗透汽化实验,研究膜的分离性能。利用SEM考察膜的形貌结构。结果发现:30℃下,溶胀度随噻吩质量分数的增加而升高,15 min后达溶胀平衡,并且在填充量为20%时最大。渗透汽化结果表明:在料液温度为30℃,噻吩质量分数为1 100μg/g时,CTAB填充量为20%的PEBAX/PVDF复合膜的渗透通量和硫富集因子分别为2.81 kg/(m2·h)和4.65。     

TiO_2/PVA杂化膜的渗透蒸发性能及结构表征

通过纳米TiO2粒子填充改性制备了新型TiO2/PVA杂化膜。红外光谱表明纳米TiO2表面的羟基与聚乙烯醇(PVA)链上的羟基存在较强的氢键作用。扫描电镜显示当TiO2的质量分数低于1.5%时,在PVA中分散均匀。X射线衍射显示纳米TiO2的加入降低了膜的结晶度。通过对含水质量分数低于20%的水/乙醇体系的脱水研究了该杂化膜的渗透性能,考察了TiO2粒子填充量、料液质量分数和温度与膜分离性能之间的关系。渗透通量J随着TiO2、水质量分数和温度的升高而增加,分离因子随着温度和水质量分数的升高而下降,在TiO2质量分数为1.5%时分离因子达到最佳值。40℃下分离质量分数85%的乙醇水溶液,分离因子可达1 590,渗透通量为0.049kg/(m2.h)。     

无机杂化海藻酸钠渗透汽化膜的制备与分离性能对比

为提高海藻酸钠(SA)膜的渗透汽化分离性能,分别采用纳米氧化铝、纳米氧化锆和纳米氧化钛对SA膜进行改性,对比分析了3种不同杂化膜渗透汽化分离性能的差异,并将分离性能较好的杂化膜应用到乙酸与乙醇酯化反应脱水的体系中。系统考察了无机纳米粒子含量对SA膜渗透汽化分离性能的影响,对杂化膜进行了接触角、傅里叶红外(FTIR)、扫描电子显微镜(SEM)、热重/差示扫描量热(TG/DSC)、X射线衍射(XRD)和拉伸强度等表征与分析。结果表明,无机纳米粒子能提高SA膜的热稳定性、机械强度和渗透通量,当无机纳米粒子与SA质量比为0.3时,掺杂TiO_2、ZrO_2和Al_2O_3的杂化膜二碘甲烷的接触角依次升高,同时渗透通量也依次升高。SA-0.3Al_2O_3杂化膜亲水性较好,然而SA-0.3ZrO_2杂化膜分离性能最优,50℃下分离水含量10%的乙醇-水溶液,膜渗透通量达到336 g·m~(-2)·h~(-1),渗透侧水含量99.97%,分离因子29990。酯化反应脱水实验表明,在80℃时,酯化反应脱水实验乙酸转化率均高于无脱水实验乙酸转化率,平衡转化率不断被打破,反应12 h后,转化率由平衡时的79.3%提高到93.9%。     

聚二甲基硅氧烷-聚丙烯酸甲酯半互穿聚合物网络结构渗透汽化膜的制备及性能

为了提高聚二甲基硅氧烷(PDMS)膜的渗透汽化性能,采用一锅法制备PDMS-PMA半互穿聚合物网络结构(semi-IPN)渗透汽化膜,通过红外光谱和扫描电镜对其进行表征,并探究其溶胀性能和渗透汽化性能。结果表明,IPN结构的形成明显提高了PDMS膜的渗透汽化性能;在原料液温度为70℃、PMA含量为10%时,semi-IPN渗透汽化膜的分离因子为42.0、总通量为923 g·m~(-2)·h~(-1)。     

活性炭填充PEG/PVDF杂化膜的脱硫性能

制备了不同活性炭(AC)填充量的AC-PEG/PVDF杂化膜,并对其形貌与结构进行了相应的表征。以噻吩/正庚烷混合物作为模拟汽油体系,研究了所制备AC-PEG杂化膜的渗透汽化脱硫性能。研究表明,填充活性炭后,膜的脱硫性能明显提高。当活性炭填充量为5%,温度为85℃时,与未填充的PEG膜相比,AC-PEG/PVDF杂化膜的渗透通量由0.43 kg·(m~2·h)~(-1)提高至1.14 kg·(m~2·h)~(-1),富硫因子由7.29提高至9.47。     

全硅沸石/聚二甲基硅氧烷渗透汽化膜制备及分离性能

考察了全硅沸石/聚二甲基硅氧烷(PDMS)渗透汽化均质膜制膜液中国液比(质量比)对渗透汽化膜性能的影响,利用均匀设计优化方法对交联时间、交联温度、全硅沸石填充鼍和PDMS中b胶量等对膜分离因子的影响进行了研究,制备了对丁醇分离性能较高的渗透汽化均质膜.50℃下,分离原料液质量分数为1.6%的丙酮-丁醇-乙醇-水溶液时,...     

新型聚乙烯醇/硅系杂化膜的制备及渗透性能

采用溶胶-凝胶法制备了聚乙烯醇（PVA）/γ-氨丙基三乙氧基硅氧烷（APTEOS）有机/无机杂化膜。用FTIR和XRD对杂化膜进行了表征。测定了膜在乙醇/水溶液中的溶胀行为。考察了杂化膜对85%（质量）的乙醇/水溶液的渗透蒸发分离性能。加入APTEOS降低了PVA的结晶度，有效控制了膜的溶胀，呈现出优良的分离性能。随着APTEOS含量的增加，杂化膜的选择性急剧增加，在5.0%（质量）时达到最大值;同时膜的渗透通量迅速增加。解决了PVA膜trade-off效应。     

聚乙烯醇-二氧化硅/聚丙烯腈杂化复合膜渗透蒸发分离己内酰胺/水溶液

制备了以聚乙烯醇(PVA)填充纳米SiO2改性膜为活性层,聚丙烯腈(PAN)超滤膜为底膜的PVA-SiO2/PAN杂化复合膜,并用于己内酰胺(CPL)脱水。用FTIR,SEM,XRD,TGA分别对膜进行了表征,并考察了膜中纳米SiO2粒子的质量分数、进料组分质量分数和温度对复合膜分离性能的影响。结果表明,引入纳米SiO2后,杂化膜的热稳定性明显提高。当膜中纳米SiO2质量分数为1.0%时,复合膜渗透蒸发分离性能最佳。60℃下此复合膜用于分离质量分数为40%的CPL溶液时,其总通量和分离因子分别达到2 177 g/(m2.h)和349。     

Fabrication and characterization of Matrimid/MIL-53 mixed matrix membrane for CO2/CH4 separation

In this study, gas separation properties of Matrimid/MIL-53 mixed matrix membranes with different MOF weight percentages (0–20 wt.%) were investigated. TEM, XRD and DLS analysis were implemented to investigate MIL-53, structure and particles size distribution. SEM, FTIR, DSC and TGA analyses were conducted to characterize the fabricated membranes. The SEM images of these membranes showed good adhesion between polymer and particles, although for 20% MIL-53 loading, particles agglomeration was observed in some areas. Moreover, surface images of the membranes showed adequate dispersion of the particles in the polymer matrix, especially at lower MOF loadings. The permeability of pure CO₂ and CH₄ gases for all membranes were measured and the ideal CO₂/CH₄ selectivity was calculated. CH₄ permeability of membranes increased slightly as the percentage of loading increased. At 20 wt.% MOF loading, void formation led to a significant increase in CH₄ permeability (300% over pure Matrimid). CO₂ permeability showed the same trend; there was a 94% increase in permeability compared to pure Matrimid for 15 wt.% MMMs. CO₂/CH₄ selectivity also increased as MOF loading increased. The highest selectivity was shown for 15 wt.% MOF loading. This membrane had 84% growth in selectivity over pure Matrimid. Although at 20 wt.% MIL-53 loading, membrane separation performance was destroyed.     

无机杂化海藻酸钠渗透汽化膜的制备与分离性能对比

为提高海藻酸钠（SA）膜的渗透汽化分离性能,分别采用纳米氧化铝、纳米氧化锆和纳米氧化钛对SA膜进行改性,对比分析了3种不同杂化膜渗透汽化分离性能的差异,并将分离性能较好的杂化膜应用到乙酸与乙醇酯化反应脱水的体系中。系统考察了无机纳米粒子含量对SA膜渗透汽化分离性能的影响,对杂化膜进行了接触角、傅里叶红外（FTIR）、扫描电子显微镜（SEM）、热重/差示扫描量热（TG/DSC）、X射线衍射（XRD）和拉伸强度等表征与分析。结果表明,无机纳米粒子能提高SA膜的热稳定性、机械强度和渗透通量,当无机纳米粒子与SA质量比为0.3时,掺杂TiO₂、ZrO₂和Al₂O₃的杂化膜二碘甲烷的接触角依次升高,同时渗透通量也依次升高。SA-0.3Al₂O₃杂化膜亲水性较好,然而SA-0.3ZrO₂杂化膜分离性能最优,50℃下分离水含量10%的乙醇-水溶液,膜渗透通量达到336 g·m^-2·h^-1,渗透侧水含量99.97%,分离因子29990。酯化反应脱水实验表明,在80℃时,酯化反应脱水实验乙酸转化率均高于无脱水实验乙酸转化率,平衡转化率不断被打破,反应12 h后,转化率由平衡时的79.3%提高到93.9%。     

PVA/PEG/TEOS杂化膜制备及性能研究

以聚乙烯醇(PVA)与聚乙二醇(PEG)共混,并与正硅酸乙酯(TEOS)进行交联反应制备杂化膜。FTIR证实杂化溶胶液发生交联反应形成共价键Si—O—C,WXRD观察表明加入TEOS改变了膜结晶度,加入PEG提高了PVA膜对乙醇/水溶液的渗透通量,但分离因子下降,随着TEOS的加入,膜的分离因子提高。在TEOS质量分数为10%时,杂化膜的分离因子达到最大。提高退火温度可以提高膜的分离因子,但通量下降。在100℃下退火12 h的杂化膜对乙醇质量分数为85%的乙醇/水溶液的分离性能最佳。     

Poly(vinyl alcohol)/Carboxyl Graphene Membranes for Ethanol Dehydration by Pervaporation

Carboxyl graphene (CG) with two functions of hybridization and crosslinking was incorporated into poly(vinyl alcohol) (PVA) matrix to form PVA/CG mixed-matrix membranes (MMMs). The membranes demonstrated excellent mechanical properties and thermal stability. The improved hydrophilicity and formed crosslinking structure led to moderate swelling. The membrane crystallinity decreased and the free volume was promoted with increasing CG loading amount. The pervaporation (PV) separation performance for ethanol dehydration indicated that both permeation flux and separation factor were enhanced simultaneously at the optimum CG loading. Subsequently, the permeation flux continued to increase while the separation factor declined at higher CG loadings.     

Photocatalytic degradation of diclofenac using hybrid MIL-53(Al)@TiO2 and MIL-53(Al)@ZnO catalysts

In this work, TiO₂ and ZnO were incorporated successfully into a MIL-53(Al) metal–organic framework (MOF) to form nanocomposites via a facile post-modification technique. The hybrid MIL-53(Al)@TiO₂ and MIL-53(Al)@ZnO were characterized by several characterization tests. The X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and field-emission scanning electron microscopy (FE-SEM) analyses showed evidence of the successful incorporation of TiO₂ and ZnO within the MIL-53(Al) framework. The thermal gravimetric analysis (TGA) analysis demonstrated the excellent thermal stability of MIL-53(Al)@TiO₂ and MIL-53(Al)@ZnO, while diffuse reflectance spectroscopy (DRS) determined the direct optical band gaps of MIL-53(Al)@ZnO and MIL-53(Al)@TiO₂ to be 3.24 and 3.34 eV, respectively. The composites were also tested for the photocatalytic degradation of diclofenac (DCF) as a micropollutant. The DCF degradation efficiency of the photocatalysts was ranked in the following order: MIL-53(Al)@TiO₂ > MIL-53(Al) > TiO₂ > ZnO > MIL-53(Al)@ZnO. The incorporation of TiO₂ enhanced the optical properties of MIL-53 (Al), which was confirmed with the superior photodegradation efficiency of MIL-53(Al)@TiO₂ (>85% in 2 h) as compared to the pristine MIL-53(Al) (around 80% in 2 h). The improvement in the photodegradation of the hybrid-MOF is mostly associated with the possible dual function of the adsorption and photodegradation mechanisms. The reusability of MIL-53(Al) and its composites was inspected over 3 cycles of photodegradation experiments with DCF. The photocatalytic activity of MIL-53(Al)@TiO₂ remained unchanged (>90%), while for MIL-53(Al) and MIL-53(Al)@ZnO a slight drop was observed over three cyclic degradation experiments. Fluorescence measurements revealed that the hydroxyl radical is an important reactive oxygen species produced by all the photocatalysts that aid in the photodegradation of DCF. Furthermore, the kinetic modelling of the photoreaction identified a second-order kinetics for all catalysts. Experiments with scavengers showed that hydroxyl radicals played a major role in the photocatalytic process, and it was found that only 2 h of treatment was sufficient to obtain a considerable chemical oxygen demand (COD) reduction of 58%.     

Pervaporation separation of isopropanol–water mixtures using mixed matrix blend membranes of poly(vinyl alcohol)/poly(vinyl pyrrolidone) loaded with phosphomolybdic acid

Mixed matrix membranes of poly(vinyl alcohol) and poly(vinyl pyrrilidone) blends were prepared by loading with phosphomolybdic acid (PMA) and their pervaporation (PV) properties were investigated for the PV separation of isopropanol. Membrane performance shown a dependence on the extent of PMA loading. The 4 wt % PMA‐loaded blend membrane had the highest separation factor of 29991, which declined considerably at higher loading. The flux of 4 wt % PMA‐loaded membrane was lower than that of nascent blend membrane. Feed water composition and temperature influenced the PV performance. Solubility selectivity was higher than diffusion selectivity. Degree of swelling was smaller after PMA loading exhibiting better separation ability. The PV results were analyzed using the Flory‐Huggins theory and sorption was dominated by Langmuir's mode. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

碳纳米管填充PDMS膜的渗透汽化性能

将碳纳米管（CNTs）填充到PDMS中制备出CNTs/PDMS杂化膜,并将其用于乙醇/水体系的分离,发现由多壁碳纳米管制备的膜分离性能优于单壁碳纳米管填充膜,在40℃下,进料乙醇浓度为5%（质量分数）时,膜的分离因子可由8.3提高到10.0,渗透通量为206.2 g·（m²·h）^-1;采用十二烷基三氯硅烷对多壁碳纳米管进行修饰,并对修饰前后碳纳米管的性能进行表征,研究表明修饰后碳纳米管表面形成疏水层,碳纳米管的疏水性增强;将修饰后的碳纳米管填充到PDMS中,可进一步提高杂化膜对乙醇的选择性,膜的分离因子可提高到11.3,渗透通量为130.9 g·（m²·h）^-1。     

Au基MOFs双功能催化剂的制备及其催化CO2与苯胺/H2反应性能

以UiO-66(Zr)、MIL-100(Fe)、MIL-100(Cr)、MIL-101(Cr)、NH 2-MIL-101(Al)为载体,Au为活性组分,制备Au/UiO-66(Zr)、Au/MIL-100(Fe)、Au/MIL-100(Cr)、Au/MIL-101(Cr)、Au/NH 2-MIL-101(Al)双功能催化剂。采用XRD、BET、NH 3-TPD、HRTEM等表征催化剂的结构,在釜式反应器中评价催化剂对CO 2与苯胺/H 2反应生成N-甲基苯胺与N,N-二甲基苯胺的N-甲基化反应性能,考察反应条件对催化剂催化性能的影响。结果表明,催化剂的XRD特征衍射峰与相应MOFs的模拟特征峰基本一致;负载Au后催化剂仍具有高的比表面积和大的孔容、孔径;不同MOFs负载Au的催化剂具有不同的酸强度和酸量;Au纳米粒子的分散性很好,粒径为(3~7)nm。制备的催化剂均具有催化CO2与苯胺/H2的N-甲基化反应性能,其中质量分数2%Au/MIL-101(Cr)催化剂催化性能最好,苯胺转化率为45.26%,N-甲基苯胺和N,N-二甲基苯胺选择性分别为73.50%和26.50%,重复使用性能优异。