TiO2 Composite Membranes Research Articles

Effect of Ta–TiO2 Nanoparticles in Anion Exchange Membranes: Improved Hydroxide Ion Conductivity and Mechanical Strength for Alkaline Water Electrolysis Cells

AbstractTo improve the properties of quaternized QPAF‐4 copolymers as anion exchange membranes, compositing with hydrophilic Ta–TiO2 particles are investigated. Flexible QPAF‐4/Ta–TiO2 composite membranes are obtained using solution‐casting and die coating methods. Cross‐sectional scanning electron microscopy reveals that the die coating method produces a more homogenous and uniform distribution of Ta–TiO2 particles in the composite membranes than the solution‐casting method. The Ta‐TiO2 particles promotes the suppression of water absorbability and dimensional swelling of the composite membranes which is more pronounced in the die coated membranes. The Ta–TiO2 increase hydroxide ion conductivity to 116.9 mS cm−1 at 80 °C for the die‐coated membrane, surpassing that of the pristine QPAF‐4 membrane (92 mS cm−1). Ta–TiO2 with the composite membranes survive in 4 m KOH at 80 °C for 1000 h, maintaining 96–112 mS cm−1 (88–99% remaining) of initial conductivity. All composite membranes exhibit higher mechanical robustness (elongation of >200%), with the die‐coated composite membranes. The optimized die coated composite membrane is fabricated in an alkaline water electrolysis cell achieving 1.63 V at 1.0 A cm−2 (75.5% efficiency).

Reduced Graphene Oxide/Waste-Derived TiO2 Composite Membranes: Preliminary Study of a New Material for Hybrid Wastewater Treatment

This work reports the preliminary results of the development of composite self-assembling membranes obtained by the combination of reduced graphene oxide (rGO) with commercial Degussa P25 titanium dioxide (TiO2). The purpose is to demonstrate the possibility of combining, in the same self-standing material, the capability to treat wastewater containing both inorganic and organic pollutants by exploiting the established ability of rGO to capture metal ions together with that of TiO2 to degrade organic substances. Moreover, this study also investigates the potential photocatalytic properties of tionite (TIO), to demonstrate the feasibility of replacing commercial TiO2 with such waste-derived TiO2-containing material, fulfilling a circular economy approach. Thus, rGO-TiO2 and rGO-TIO composite membranes, 1:1 by weight, were prepared and characterized by SEM-EDX, XRD, thermogravimetry, as well as by Raman and UV-Vis spectroscopies to verify the effective and homogeneous integration of the two components. Then, they were tested towards 3-mg L-1 aqueous synthetic solutions of Fe3+ and Cu2+ ions to evaluate their metal adsorption ability, with values of the order of 0.1-0.2 mmol gmembrane-1, comparable or even slightly higher than those of pristine rGO. Finally, the ability of the composites to degrade a common organic pesticide, i.e., Imidacloprid®, was assessed in preliminary photocatalysis experiments, in which maximum degradation efficiencies of 25% (after 3 h) for rGO-TiO2 and of 21% (after 1 h) for rGO-TIO were found. The result of tionite-containing membranes is particularly promising and worthy of further investigation, given that the anatase content of tionite is roughly 1/6 of the one in commercial TiO2.

Electrically conductive TiO2/CB/PVDF membranes for synchronous cross-flow filtration and solar photoelectrocatalysis

Combining photocatalysis (PC) and membrane filtration (MF) has emerged as an attractive technology for water purification, however, the water purification efficiency and membrane fouling are still challenging. Herein, we report a novel photoelectrocatalytic (PEC) membrane mediated by a ternary polyvinylidene fluoride (PVDF)-carbon black (CB)–TiO2 composite conductive membrane synthesized by a phase inversion method assisted by the mixed surfactants of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS). The resultant electrically conductive TiO2/CB/PVDF membrane features a homogeneous surface with obvious pore size of 20–150 nm, a thickness ∼116 μm, and an average resistivity as low as ∼3.165 Ω∙m. The cooperation of PVP and SDS surfactants dramatically improves the organic-inorganic interactions and thus eventually enhances the porosity, stability of porous structure, mechanical stability, and conductivity and electrochemical properties of the hybrid membrane. Upon the solvent evaperation of the wellblended casting solution and the phase inversion, TiO2/CB preferentially exist on the surface of PVDF membrane, enabling the efficient PEC degradation of organic pollutants. The synergistic coupling of TiO2 and CB in PVDF membrane results in efficient PEC properties with bi-functional membrane antifouling and enhanced water purification in azo dyes decolorization under the stationary mode and in our lab-made continuous cross-flow PEC system, superior to those by photocatalysis and electrocatalysis. The developed synchronous MF and PEC system mediated by the conductive TiO2/CB/PVDF membrane proves to a feasible route to improving the self-cleaning properties of the polymer membrane while simultaneously increasing the water decontaminating efficiency.

Fabrication of Al2O3 supported TiO2 membranes for photocatalytic applications

A facile sol–gel spin coating process to synthesise mesoporous nanocrystalline Al2O3 supported TiO2 photocatalytic membranes performance has been reported. Titania sol containing lauryl lactyl lactate surfactant as a pore forming agent was employed to improve the porous structure of TiO2 materials. The sol was spin coated on Al2O3 support to synthesise TiO2/Al2O3 membranes. The composite membranes were dried and calcined. The above procedure was repeated for three times. The fabricated TiO2 composite membrane has been utilised for the photocatalytic degradation of methylene blue dye as a model pollutant. The highest percentage degradation of about 99.25% was observed at pH 12. Such membranes can be employed very efficiently in waste water treatment systems, separation of gases and liquid mixtures, treating microorganisms and also for self-antifouling action.

Reduced graphene oxide/TiO2(B) immobilized on nylon membrane with enhanced photocatalytic performance

Taking advantage of the unique properties of reduced graphene oxide (rGO) and monoclinic crystalline titanium dioxide (TiO2(B)) nanomaterials, a novel rGO–TiO2(B) composite membrane (MrGO–TiO2(B)) was constructed by UV-light-assisted self-assembly of rGO and TiO2 on a nylon membrane. The structure of MrGO–TiO2(B) was characterized by scanning electron microscopy, transmission electron microscopy, UV‐visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analysis. Through 2D/2D self-assembly, rGO and TiO2(B) were more tightly combined, and then MrGO–TiO2(B) exhibited outstanding photocatalytic activity and an excellent methylene blue (MB) removal rate. MB was completely removed in 60 min at a constant rate of 0.042 min−1 by the MrGO–TiO2(B)/H2O2/MB system upon solar simulating Xe lamp irradiation. The synergistic effect of rGO and TiO2(B) facilitated the photocatalytic degradation of MB. TiO2(B) was excited and generated electrons and holes upon irradiation. Some electrons migrated to the surface of TiO2(B) to react with H2O2 to produce hydroxyl radicals (OH), while the other electrons migrated to the surface of rGO to react with H2O2, producing OH. In addition, a number of superoxide radicals (O2−) was detected. The holes in the valence band of TiO2(B) directly oxidized MB. The catalytic activity of MrGO–TiO2(B) toward MB degradation remained stable after four rounds of reuse. Therefore, the surface modification of a nylon membrane with TiO2(B) and rGO can serve as a promising route to fabricate photocatalytic membranes for use in the water treatment industry.

Functionalized TiO2 mediated organic-inorganic composite membranes based on quaternized poly(arylene ether ketone) with enhanced ionic conductivity and alkaline stability for alkaline fuel cells

In this work, quaternized poly(arylene ether ketone) (QPAEK)/functionalized TiO2 (f-TiO2) composite membranes were fabricated with different f-TiO2 contents (1, 3, 5, 7, and 9 wt%), and the structure of the materials was characterized by 1H NMR, ATR-FT-IR, XRD, XPS, and FE-SEM. The addition of f-TiO2 enlarges the ion cluster in the membrane due to enhancing the interaction between the functional groups, and SAXS analysis revealed an extension of the ion domain size with an increase in the filler content (up to 5 wt%). In particular, the composite membrane with 5 wt% f-TiO2 displayed the highest ion conductivity (74.6 mS cm−1); such a result was attributed to the formation of water traps by the deliquescence of TiO2 and enhanced interfacial interactions between the pure organic polymers and inorganic nanomaterials. This work proves that a composite membrane with an appropriate f-TiO2 concentration is a promising candidate for application to anion exchange membranes.

Precisely Engineered Photoreactive Titanium Nanoarray Coating to Mitigate Biofouling in Ultrafiltration.

To combat biofouling on membranes, diverse nanostructures of titanium dioxide (TiO2) have emerged as effective antimicrobial coatings due to TiO2's abilities to transport charge and photoinduce oxidation. However, TiO2 composite polymeric membranes synthesized using traditional methods of growing crystals have proven chemically unstable, with loss of coating and diminishing antimicrobial performance. Thus, new fabrication methods to enhance durability and efficacy should be considered. In this work, we propose a stepwise approach to construct a stable, uniform TiO2 nanoarray of regularly spaced, aligned crystals on the surface of a polytetrafluoroethylene ultrafiltration membrane using precisely controlled atomic layer deposition (ALD) followed by solvothermal deposition. We demonstrate that ALD can uniformly seed TiO2 nanoparticles on the membrane surface with atomic-scale precision. Subsequently, solvothermal deposition assembles and aligns a uniform TiO2 nanoarray forest. In the presence of sunlight, this TiO2 nanoarray effectively inactivates any deposited bacteria, increasing flux recovery after membrane cleaning. By systematically investigating this antimicrobial activity, we found that TiO2 both physically damages cell membranes as well as produces reactive oxygen species in the presence of sunlight that inactivate bacteria. Our study provides an effective bottom-up synthesis scheme to optimize and tailor antifouling TiO2 coatings for ultrafiltration and other surfaces for a wide range of applications.

As(III) Oxidation Mediated By Reactive Oxygen Species in-Situ-Generated from Pre-Photocharged TiO2 and WO3 Composite Catalyst Membrane Filters

The photocatalytic oxidation system has been widely investigated as a pretreatment process for efficient removal of arsenic. However, its practical use for the arsenite (As(III)) oxidation is limited by several problems such as low oxidation efficiency under dark condition and difficult separation of catalysts from treated water. This study investigated light-charged TiO2 and WO3 (TW) composite-embedded inorganic membrane filter system as a practical method for preoxidative treatment of As(III) even without the addition of chemical oxidants under dark condition. And this study demonstrated that reactive oxygen species (ROSs ; O2 ·- and HO2 ·) in pre-photocharged TW composite catalyst membrane filter. TW membrane filters were charged under UV or simulated solar light (AM 1.5; 1 sun) irradiation and subsequently transferred to a once-through flow type system for testing As(III) oxidation in the dark condition. The As(III) oxidation efficiency increased with increasing photocharging time, weight ratio of WO3 and solution pH. These conditions enable the sufficient generation of ROSs via O2 reduction using electrons accumulated in TW during pre-photocharging for achieving the effective oxidation of As(III) in the dark condition. The oxidation capability of TW system was completely recovered after re-photocharging. TW-embedded membrane filter system can be easily reused after recharging process without the requirement of additional physical separation steps under ambient dark condition.

Poly (2, 6-dimethyl-1, 4-phenylene)/polysulfone anion exchange membrane blended with TiO2 with improved water uptake for alkaline fuel cell application

A series of anion exchange membranes (AEM) based on poly (2, 6-dimethyl-1, 4-phenylene) (PPO) and polysulfone (PSF) blended with TiO2 were prepared and investigated. The water uptake, swelling ratio, ion exchange capacity, ion conductivity (IC) and thermal stability of the AEMs increased with increasing content of TiO2 within the composite membrane. The QPPO/PSF/TiO2 AEMs showed excellent thermal stability, high IC of 54.7 mS cm−1 at 80 °C, excellent alkaline stability and good performance when assembled in a methanol alkaline fuel cell. The highest peak power density of 118 mW cm−2 at a load current density of 300 mA cm−2 was observed for the QPPO/PSF/2%TiO2 composite membrane at 60 °C. The life time test of the fuel cell showed good membrane durability over a 60 h period. The results of this study suggest that the fabricated AEMs have good prospects for alkaline anion exchange membrane fuel cell applications.

Sulfonated poly(ether ether ketone)/s–TiO2composite membrane for a vanadium redox flow battery

ABSTRACTThe SPEEK/s‐TiO2composite membrane was prepared by blending sulfonated poly(ether ether ketone) (SPEEK) and sulfonated titanium dioxide (s‐TiO2) nanoparticles. The important physiochemical parameters such as proton conductivity, water uptake, swelling degree and ion exchange capacity of the composite membrane were measured. The thermal stability and chemical stability were also tested. It was observed that the SPEEK/s‐TiO2composite membrane exhibited the best selectivity (7.13 × 104 S·min·cm−3) accompanying high proton conductivity (0.061 S·cm−1) and low tetravalent vanadium ion (VO2+) permeability (8.55 × 10−7cm2·min−1) compared with Nafion117, SPEEK and SPEEK/TiO2membranes. The battery performance with these membranes was characterized by charge–discharge cycling tests and it was found that the SPEEK/s‐TiO2composite membrane showed the highest energy efficiency (EE) up to 82.3%, indicating the SPEEK/s‐TiO2composite membrane is a candidate for vanadium redox flow battery (VRFB) application. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48830.

RGO/PDA/Bi12O17Cl2–TiO2 composite membranes based on Bi12O17Cl2–TiO2 heterojunctions with excellent photocatalytic activity for photocatalytic dyes degradation and oil–water separation

In the study, the reduced graphene oxide/graphitic Bi12O17Cl2–TiO2 heterojunctions sheet membrane(RGO/PDA/Bi12O17Cl2–TiO2) was fabricated by the dopamine modification and assembling the RGO/PDA/Bi12O17Cl2–TiO2 composites on the surface of commercial CA(cellulose acetate) membrane to degrade methylene blue (MB) and p-chlorophenol (4-CP) to harmless products. These membrane materials were comprehensively characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results showed that RGO/PDA/Bi12O17Cl2–TiO2 nanofiber membrane exhibited extremely high degradation performance with a good distribution of RGO/PDA/Bi12O17Cl2–TiO2 on the CA nanofiber membrane surface. Besides, the complete photodegradation of 100 mL MB (15 mg L−1) solution and 100 mL 4-CP (15 mg L−1) solution with artificial visible-light was achieved after 100 min and 160 min, respectively. The RGO/PDA/Bi12O17Cl2–TiO2-CA composite membrane revealed the ability of continuous and simultaneous flow-through separation of oil/water emulsion and degradation of soluble organic dye under visible-light irradiation in a short time. Moreover, the nanofiber membranes exhibited excellent stability and reusability for MB-containing oil–water mixed emulsion separation has great potential to be applied in industrial application.

Green synthesis of TiO2 nanoparticles using Cajanus cajan extract and their use in controlling the fouling of ultrafiltration PVDF membranes

Polyvinylidene fluoride (PVDF)/TiO2 composite ultrafiltration membranes were fabricated using different loadings of TiO2 NPs synthesized by the green route using an extract of Cajanus cajan. XRD analysis confirmed the synthesis of TiO2 nanoparticles of size 10 nm using Debye Scherrer’s equation. High hydrophobicity of PVDF restricts its successful application due to fouling in the membrane. Therefore, composite membranes were prepared via the phase inversion route and characterized by contact angle and permeation tests. The BSA filtration experiments revealed that membrane with 0.5 wt% of TiO2 exhibits excellent hydrophilicity, permeation flux, high rejection ratio, and good antifouling performance. It was observed that the fouling characteristic of the membrane is governed by the surface roughness of the membrane, and with increasing loading of TiO2 the surface roughness decreases indirectly enhancing the antifouling property of membranes. The adsorption capacity of bovine serum albumin on the membrane surface decreased from 2.85 to 2.15 mg cm−2 as the TiO2 loading increased from 0 to 0.02 g TiO2/g PVDF. Fouling was found due to cake formation in ultrafiltration and can be explained by Hermia’s fouling model suggesting that the solutes are not deposited into the pores, which indicates that the fouling process is physically reversible.

Synthesis of titanium (IV) oxide composite membrane for hydrogen production through alkaline water electrolysis

Alkaline water electrolysis is one of the most efficient methods for the hydrogen production. In this method widely used as the asbestos membrane as a separator, but this material is hazardous for health, causing cancer, in order to limit the usage of an asbestos separator. In this present study, a novel TiO2 composite membrane was synthesized from polysulfone (PSF), PVP and titanium oxide (TiO2) by phase inversion precipitation technique. The synthesized membranes were characterized by FT-IR, FE-SEM and XRD techniques. Further, membranes electrolysis performance studied in in-house fabricated small scale alkaline water electrolyser experimental setup of a 10 cm2 cell. These synthesized membranes were effectively improved the hydrogen production rate and purity compared to conventional asbestos separators. A current density of 600 mA/cm2 along with 30 ml/min hydrogen with 99.9% purity was obtained when operating the cell in 30 wt% KOH and 80 °C at 2 V. In electrolysis process, various experimental parameters considered such as an effect of temperature (30–80 °C) and KOH concentration (5–30 wt %) were studied. Hydrogen quantity measured by liquid displacement unit, purity determined by ENDEE portable hydrogen gas analyzer and gas chromatographic (GC) techniques. These synthesized composite membranes are low cost and showed excellent electrochemical performance and stability in alkaline medium.

Fabrication and photocatalytic activity of TiO2 composite membranes via simultaneous electrospinning and electrospraying process

In present study, a simultaneous electrospinning and electrospraying (SEE) process was employed to produce microclusters of TiO2 nanoparticles and interlock them in nanofibrous network. The photocatalytic composite membranes (PCMs) were fabricated by electrospraying TiO2 nanoparticle suspension into microcluster form that dispersed and entrapped within nylon-6 electrospun fiber membrane. Three PCMs membrane with TiO2 content of 52.0, 83.6, and 91.7wt.% were successfully fabricated. The membrane consisted of TiO2 microclusters, ranging in sizes from around 0.3 to 10μm, distributed uniformly within the nylon-6 nanofibrous network. PCMs photocatalytic activity against Methylene Blue (MB) in aqueous solution showed more than 98% MB removal efficiency after 120min of photocatalytic oxidation (PCO) for all PCMs. For PCM with the highest TiO2 content tested for 5 PCO cycles, it was found that most of their TiO2 content remained incorporated within the nanofibrous structure. The concept of nanoparticles clusters entrapment with SEE fabrication employed here provide a simple and effective method for reducing detachment of nanostructure phase from nanocomposite membrane.

Polysulfone/N,Pd co-doped TiO2 composite membranes for photocatalytic dye degradation

Hybrid multifunctional membranes capable of simultaneously performing photocatalysis and filtration can lead to improved water treatment processes. Transparent polymeric membranes exhibiting two surfaces that can come directly into contact with the polluted water can be desirable candidates for photocatalyst deposition. Different proportions of N,Pd co-doped TiO2 were embedded in a PSf polymeric membrane through the phase inversion method and the membrane evaluated for the degradation of a dye (eosin yellow) under visible light irradiation. The synthesised hybrid membranes were characterised by FTIR, Raman Spectroscopy, DRUV-Vis, SEM, EDS, XRD, AFM, SAXSpace and Contact angle measurements. Anatase type N,Pd co-doped TiO2 nanoparticles were successfully entrapped in the PSf membrane through a simple phase inversion method. Addition of TiO2 to the PSf membrane led to improved membrane porosity, wettability and visible light activity while membrane integrity was maintained. Higher TiO2 loadings resulted in increased membrane roughness and particle aggregation of the embedded TiO2. Up to 92% dye degradation was realised with the 7% N,Pd TiO2/PSf nanocomposite membrane after 180 min of visible light irradiation. Degradation kinetics followed a pseudo first order model, evidence of possible changes in the membrane properties upon irradiation with simulated solar radiation. Solar active photocatalytic membranes fabricated through embedding doped TiO2 nanoparticles are promising candidates for low energy water purification in marginalised rural communities.

Highly selective sulfonated poly(ether ether ketone)/titanium oxide composite membranes for vanadium redox flow batteries

To lower the cost and enhance the selectivity of membranes used in vanadium redox flow batteries (VRFBs), sulfonated poly(ether ether ketone) (SPEEK)/ titanium oxide (TiO2) composite membranes with different degrees of sulfonation (DS) (prepared at different time durations of 3h, 5h and 7h) and various TiO2 nanoparticles loadings (3%, 5% and 7%) were prepared. Optimum DS and TiO2 nanoparticles loading were confirmed by different characterization techniques including 1H NMR, scanning electron microscopy, water uptake, swelling ratio, proton conductivity, vanadium ion permeability and thermal stability. Results show that 5h SPEEK/5% TiO2 composite membrane possessed comprehensive merits, especially high ion selectivity (72.55 × 103Smincm−3) due to the blocking effect of TiO2 nanoparticles and good proton conductivity. TiO2 nanoparticles combined very well with SPEEK due to strong interaction, as deduced from flux tests. The chemical and oxidative stability were sufficiently good for applications of VRFB. The VRFB single cell with 5h SPEEK/5% TiO2 composite membrane exhibited excellent performance including high coulombic efficiency (98.3%), high energy efficiency (82.9%), long self-discharge time and low capacity loss compared to Nafion 117. Hence, SPEEK/TiO2 composite membranes can potentially be promising substitute for Nafion in VRFBs.

Bifunctional regenerated cellulose membrane containing TiO2 nanoparticles for absorption and photocatalytic decomposition

A simple and green method was presented to embed TiO2 on regenerated cellulose membranes via cellulose dissolution-regeneration process. The physical, chemical and mechanical properties of the composite membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier- Transform Infrared (FTIR), ultraviolet (UV) - visible spectroscopy and tensile test. The results indicated that cotton linter has been converted from cellulose I to cellulose II after the regeneration process, while the TiO2 nanoparticles embedded inside the membrane maintaining its original crystal structures. The TiO2 composite membranes possessed high ability of water absorption with total pore volume ranged from 0.45±0.01 to 0.53±0.02 cm3/g. The elongation at break of the prepared membranes increased 29% averagely from dry state to wet state. The tensile strength of the membranes remained at a minimum value of 0.50±0.03 MPa in wet state thus enabled the films to withstand in wet for long period of time under weak UV irradiation. The regenerated cellulose membranes with TiO2 performed well in photocatalytic activity while exhibiting distinct absorption abilities. This study provides a potential application in energy-saving decomposition system in which the dye compound can be easily removed via two simultaneous pathways: Absorption and photocatalytic decomposition.

Cross flow microfiltration of oil-water emulsions using clay based ceramic membrane support and TiO2 composite membrane

The main objective of this work is to study the effect of cross flow filtration conditions on the separation of oily wastewater using ceramic support and TiO2 membrane. Firstly, the low cost clay based ceramic membrane support was prepared by uniaxial compaction method using combination of pyrophyllite, quartz, feldspar, kaolin, ball clay and calcium carbonate along with PVA as a binder. Subsequently, TiO2 composite membrane was fabricated via hydrothermal route employing TiO2 sol derived from TiCl4 and NH4OH solution. Cross flow microfiltration investigations were carried out by utilizing oil-water emulsion concentration of 200mg/L at three distinct applied pressures (69–207kPa) and three cross flow velocities (0.0885, 0.1327, and 0.1769m/s). Compared to ceramic support, TiO2 composite membrane demonstrates better performance in terms of flux and removal efficiency of oil and also the rate of flux decline during filtration operation is lower due to highly hydrophilic surface of the TiO2 membrane. TiO2 membrane displays the oil removal efficiency of 99% in the entire range of applied pressures investigation, while ceramic support shows 93–96% of oil removal.

Macroporous PVDF/TiO2 membranes with three-dimensionally interconnected pore structures produced by directional melt crystallization

Techniques to fabricate polymer membranes with improved performance have been actively developed over the past several decades. Most conventional manufacturing processes are based on amorphous phase separation, which often restricts the formation of interconnected pores, resulting in high tortuosity. Herein, we demonstrate the fabrication of polyvinylidene fluoride (PVDF)/TiO2 composite membranes with highly interconnected pore structures. Vertically oriented pores could be produced by continuous growth of solvent crystals under a controlled temperature gradient and then removing solvent crystals via freeze drying. Crystal nucleation and growth could offer better control of pore morphology, size, and connectivity. The incorporation of TiO2 into PVDF membranes not only improved the hydrophilicity, but also enhanced protein resistance of the membrane. The pure water flux of PVDF/TiO2 composite membranes with interconnected porosity was excellent, six times higher than that of commercial PVDF membranes having similar pore size. This novel preparation method could expand the variety of structures and properties of such membranes and hence their areas of application.

Enhancing antifouling performance of poly(l‐lactide) membranes by TiO2 nanoparticles

ABSTRACTPoly(l‐lactide) (PLLA)/TiO2 composite membranes were fabricated by immersion precipitation method. The resulting membranes were characterized using various methods including XRD, ATR‐FTIR, TGA, DSC, SEM, goniometer, and molecular weight cut‐off. The antifouling performance of the membrane was investigated through the filtration experiments of the oil/water emulsion. XRD, SEM, and ATR‐FTIR results indicated that TiO2 was successfully introduced into the membrane, while DSC and TGA indicated the enhancement of thermal stability of membrane. The improvement of membrane hydrophilicity was confirmed by goniometer. In addition, the pore size and porosity on the membrane surface varied obviously with increasing the TiO2 loading. It was concluded that PLLA/TiO2 composite membranes had better antifouling and recycling performance compared with the pure PLLA membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43542.