Modified Polypropylene Membrane Research Articles

Preparation of micro-nano particles modified discarded face-mask by a versatile thermocompression modification approach and its application to emulsion separation

ABSTRACT The discarded face mask has caused plastic pollution, which damages the environment. From the perspective of environmental protection and energy-saving, it is a good method to modify the discarded face mask and apply it in other fields, such as emulsion separation. However, the polypropylene (PP) membrane is hard to be modified due to its high stability. To solve this problem, the nano-Al2O3 powder was used to modify the PP membranes by a versatile thermocompression method. The modified PP membrane (PP-Al2O3-0.05) exhibited better oil-in-water emulsion separation performance than the original PP membrane. The modified PP membrane can be used to separate many kinds of emulsions, and the separation flux was above 2200 L•m−2•h−1. And the continuous separation performance of the modified PP membrane was also favorable. Moreover, to verify the versatility of the thermocompression technology, different kinds of materials were applied to modify the PP membrane by this method. We believe that the simple method has practical applications for reusing discarded face masks to alleviate environmental pressure.

Polypropylene membranes with high adsorption capacity and anti-adhesion properties achieved by hydrophobic interactions and hydrogen bonded self-assembly for uranium extraction from seawater

Herein, we have developed a mild and convenient strategy to enable polypropylene (PP) fibrous membranes with abundant adsorption sites for the selective extraction of uranium from seawater. Lysozyme was chosen as the pre-coatings because of its strong hydrophobic interactions with PP membranes. Then, lysozyme and phytic acid were set as hydrogen bonding self-assembling components since both of them are proved with a great binding affinity towards uranium. The contents and thickness of the lysozyme-phytic acid coatings could be linearly tuned due to the excellent controllability of self-assembly. The obtained PP membrane could achieve adsorption capacity as high as 90.07 mg-U/g-membrane (2143.83 mg-U/g-coating). In addition, the lysozyme would endow the PP membranes with outstanding anti-fouling, anti-bacteria, and anti-adhesion properties. The modified membranes could maintain more than 85% of adsorption capacity even with the interferences of bacteria and model pollutants. We also applied the membranes for dynamic adsorption by taking advantage of membrane filtrations. The adsorption capacity during the dynamic process increases with the flow rates and the layer numbers because more uranyl ions could contact with the adsorption sites. The modified PP membranes could obtain 1.15 mg/g of uranium after 15 days when the concentration of uranium is set as the same as the uranium concentration (3.3 μg/L) in natural seawater.

Dawson-type polyoxometalate modified separator for anchoring/catalyzing polysulfides in high-performance lithium-sulfur batteries

Considering ultrahigh energy density as well as the cost-effectiveness of lithium-sulfur batteries (Li-S, LSBs), it is considered the most outstanding battery. However, the shuttling behavior and sluggish conversion of polysulfides (LiPSs), and the dendrite formation seriously impede the practical applications of LSBs. The modified separator is an effective method to solve the above problems. Herein, we propose a Dawson-type polyoxometalate (K6P2W18O62, P2W18) modified polypropylene membrane (P2W18/PVDF/PP) with multiple functions for inhibiting the diffusion of LiPSs, promoting the redox kinetics of LiPSs conversion, avoiding the dendrite formation, and promoting Li+ rapid transfer. Based on spectroscopic techniques as well as electrochemical dates, it was confirmed that P2W18 can effectively adsorb LiPSs and accelerate LiPSs conversion kinetics to improve the electrochemical performance of LSBs. As a result, LSBs with P2W18/PVDF/PP separator show an initial specific capacity of 724 mAh g–1 at 3.0 C with excellent cycling stability over 400 cycles. The result offers a new perspective for exploring the role of Dawson-type polyoxometalate in extending cycling life and increasing specific capacity in LSBs.

Biomimetic modified polypropylene membranes based on tea polyphenols for efficient oil/water separation

In recent years, the fabrication of efficient, green, and anti-pollution membrane materials has attracted extensive attention in the field of oil/water separation. Herein, a facile co-deposition strategy based on the reaction between tea polyphenols (TP) and γ-aminopropyltriethoxysilane (APTES) was proposed. Hierarchical nanoparticles were successfully constructed on the surface of polypropylene (PP) melt-blown nonwoven via a mild process, which endowed it with superhydrophilicity and underwater superoleophobicity. The as-prepared membranes could realize the efficient separation of oil/water mixtures, whether for vegetable oil/water mixtures or mineral oil/water mixtures. All separation efficiencies were above 99.1% and the optimal permeation flux was as high as 113,000 L m−2 h−1. The recyclability and recoverability of the coated membranes were further evaluated by conducting “30 + clean + 30” cyclic experiments. Additionally, the modified membranes also exhibited superior underwater oil resistance, low oil adhesion, and self-cleaning capacity. Good corrosion resistance allowed them to be used in acidic and mildly alkaline environments, and the treated membranes could keep stable underwater superoleophobicity though placed in ultrasonic water for 60 min. Therefore, the modified PP membranes with high efficiency, energy saving, environmental protection, and anti-pollution could be applied in the treatment of oily wastewater.

New material for arsenic (V) removal based on chitosan supported onto modified polypropylene membrane.

This paper presents a new material easily synthesized and with low cost, with the possibility of remove arsenic and the potential capability for the remediate water bodies. In this work, the efficiency in removing arsenic of the chitosan, supported onto modified polypropylene membrane, was studied using an aqueous As(V) solution of 0.4 mg/L, achieving a removal efficiency of 75%, which corresponds to an adsorption capacity of 0.031 mg/g. The As(V) adsorption depends on pH and the degree of chitosan grafting on the polypropylene membrane. A pseudo-second-order equation describes the adsorption of the membrane, classifying it as a chemisorption process. The chitosan supported on the membrane was characterized by the analysis of wettability, FT-IR-ATR, SEM-EDS, XRD powder, and surface charge. The As ions coordinate to the chitosan polar groups, allowing their removal from the aqueous solution.

Biofouling 방지를 위한 항균성 멤브레인 필터의 제조 : GMA의 그라프트 중합과 아민화/술폰화에 의한 표면개질

Biofouling is a major problem of membrane processes in water and wastewater treatment. One of the anti-biofouling strategies is to construct an antimicrobial membrane surface. In this study, polypropylene(PP) microfiltration membranes with antimicrobial property were fabricated by grafting glycidyl methacrylate(GMA), followed by amination or sulfonation with ethylenediamine or sodium sulfite solution. GMA was facilely grafted onto PP membrane by UV-induced graft polymerization, and the graft chains were easily aminated or sulfonated by a simple chemical reaction. The modified PP membranes were characterized by FT-IR, SEM, water permeability and antimicrobial tests. The PP membranes modified by grafting GMA improved the water permeability due to the hydrophilization of the surface, but the antimicrobial activity was too low. In contrast, aminated or sulfonated PP membranes exhibited high antimicrobial activity against both E. coli and S. aureus without a significant reduction in the water permeability.

ZIF-8 Modified Polypropylene Membrane: A Biomimetic Cell Culture Platform with a View to the Improvement of Guided Bone Regeneration.

PurposeDespite the significant advances in modeling of biomechanical aspects of cell microenvironment, it remains a major challenge to precisely mimic the physiological condition of the particular cell niche. Here, the metal–organic frameworks (MOFs) have been introduced as a feasible platform for multifactorial control of cell-substrate interaction, given the wide range of physical and mechanical properties of MOF materials and their structural flexibility.ResultsIn situ crystallization of zeolitic imidazolate framework-8 (ZIF-8) on the polydopamine (PDA)-modified membrane significantly raised surface energy, wettability, roughness, and stiffness of the substrate. This modulation led to an almost twofold increment in the primary attachment of dental pulp stem cells (DPSCs) compare to conventional plastic culture dishes. The findings indicate that polypropylene (PP) membrane modified by PDA/ZIF-8 coating effectively supports the growth and proliferation of DPSCs at a substantial rate. Further analysis also displayed the exaggerated multilineage differentiation of DPSCs with amplified level of autocrine cell fate determination signals, like BSP1, BMP2, PPARG, FABP4, ACAN, and COL2A. Notably, osteogenic markers were dramatically overexpressed (more than 100-folds rather than tissue culture plate) in response to biomechanical characteristics of the ZIF-8 layer.ConclusionHence, surface modification of cell culture platforms with MOF nanostructures proposed as a powerful nanomedical approach for selectively guiding stem cells for tissue regeneration. In particular, PP/PDA/ZIF-8 membrane presented ideal characteristics for using as a barrier membrane for guided bone regeneration (GBR) in periodontal tissue engineering.

Computational modeling of metal ions removal by a modified polypropylene membrane

A model of polypropylene membrane modified with acrylic acid has been proposed to understand the experimental removal efficiency of Cd2+, Cu2+ and Pb2+. To provide a description for bimetallic complexes, Ab Initio MD and Quantum Topological Analysis were carried out. ΔKS,q and ΔG values have been calculated and it has been observed that ΔKS(12acr) drives the metal absorption, where the stabilization is higher for copper–containing complexes. ΔKS(12acr) has presented the same tendency as the experimental removal efficiency. Thus, the model proposed can explain the experimental data and it can clarify the metal contributions to the absorption process.

Fouling tendency of PDA/PVP surface modified PP membrane

Hydrophilic modification is a promising method to inhibit fouling formation on ultrafiltration membrane. In this work, hydrophilic modification on polypropylene (PP) ultrafiltration membrane was conducted by air assisted polydopamine (PDA) coating with the addition of polyvinylpyrrolidone (PVP). The results showed that the PDA/PVP coating successfully improved the hydrophilicity of the PP membrane that indicated by the decrease of water contact angle and the increase of pure water flux. The hydrophilic modification was also able to reduce the formation of irreversible fouling that has been proved by the increase of flux recovery ratio from 68.95% to 86.14–87.71% after modification. Nevertheless, based on Hermia's model, the most dominant fouling mechanism on PP membrane did not affected by PDA/PVP coating.

Surface modified polypropylene membranes for treating hydraulic fracturing produced waters by membrane distillation

ABSTRACTMembrane distillation is an emerging technology for treating hydraulic fracturing flowback and produced waters (PW). Suppression of membrane fouling by inorganic and polar and non-polar organic compounds is a challenge. Here, polyhydroxyethyl methacrylate, polyacrylic acid, polvinylallyl imidazolium bromide and polyvinylhexyl imidazolium bromide chains have been grafted from the surface of polypropylene membranes. Fouling happens initially due to adsorption of organic compounds followed by scale formation. When challenged with PW, membranes modified with polvinylallyl imidazolium bromide chains provided the greatest resistance to fouling. For electrocoagulation pretreated PW and synthetic PW that contained mainly inorganic species, the flux decline was much less.

(Invited) Surface Modified Polypropylene Membrane for High Performance Lithium Metal Coin and Pouch Cell Batteries

For the advanced Li metal batteries, lithium (Li) metal is considered as anode electrode because of its lowest redox potential (–3.04 V vs. standard hydrogen electrode), highest theoretical specific capacity (3,860 mAh g-1), and the low density (0.59 g cm-3). Nevertheless, Li metal anode seriously impede its practical use for viable market because of short-circuit based safety risk associated to dendrite growth and low Coulombic efficiency. Understanding those fundamental challenges, we designed a multifunctional tri-layer membrane by percolating a layer of a polydopamine (PDA) followed by depositing graphene-carboxymethyl cellulose (Gr-CMC) on the top of polypropylene (PP) separator, hypothesizing to improve the cycle stability and performance of Li metal electrodes. The novel, new trilayer comprising Gr-CMC layer of the designed separator depicted an excellent electrolyte wettability, an additional capacity of Li storage and an enhanced electrical conductivity. In Li/Cu half-cell the Coulombic efficiency was significantly enhanced over 200 cycles after implementing PDA/Gr-CMC separator. LiFePO4 cathode vs Li full cell with trilayer separator directed to long term cycle retention (1000 cycles) with enhanced rate capability. Apart from room temperature, electrochemical stability at 0 oC demonstrated the sanguine potential of PDA/Gr-CMC separator for practical Li-metal batteries. Beyond coin cells, pouch cell studies and cycling abilities will be demonstrated.

Modification and Applications of Hydrophilic Polypropylene Membrane

Polypropylene (PP) is one of the most important polymers for microporous membrane due to its high void volume, well-controlled porosity, high thermal and chemical stability, and low cost. However, the hydrophobicity of PP becomes a limitation to broaden its applications. Furthermore, membrane fouling occurs more seriously on hydrophobic membranes than hydrophilic ones. To solve this problem, surface modifications have been developed to enhance PP membrane hydrophilicity without changing its bulk properties. Graft polymerization and plasma treatment are the most popular techniques for surface hydrophilization. Some studies showed that highly hydrophilic PP membranes with water contact angle less than 20° could be obtained by plasma treatment and graft polymerization. Furthermore, during plasma treatment, polar groups were formed on the PP membrane surface thus increased water uptake. To bring brief explanation on various research trends for PP modification, this paper provides a review of surface hydrophilization of microporous PP membrane, including plasma treatment and graft polymerization. The effects of surface modification on PP membrane performance such as porosity, water contact angle, and water flux are also discussed. In addition, the applications of modified PP membrane are presented as well.

Interpenetrating polymers supported on microporous polypropylene membranes for the transport of chromium ions

Abstract Modifying polypropylene membranes with interpenetrating polymer networks (IPNs) through the incorporation of poly(glycidyl methacrylate-N-methyl- d -glucamine) (P(GMA-NMG)) was performed by in situ synthesis via radical polymerization. The surface of the polypropylene membrane was activated by hydrophilic grafted polyelectrolyte, and then, pressure injection was used for the impregnation of the reactive solution in the membrane. Two types of pore-filled membranes were synthesized, chelating interpenetrating homopolymer networks of P(GMA-NMG), and chelating-ion exchange interpenetrating polymer networks (e.g., P(GMA-NMG)/P(AA), P(GMA-NMG)/P(AMPSA), and P(GMA-NMG)/P(ClVBTA)). After their synthesis, the modified polypropylene membranes were characterized using techniques such as the electrokinetic potential, SEM, FT-IR, and Donnan dialysis to corroborate the chromium ion transport. The P(GMA-NMG) and complex network membranes exhibited a hydrophilic character with a water-uptake capacity between 20% and 35% and a percentage of modification between 4.0% and 7.0% in comparison with the behavior of the unmodified polypropylene membrane. Hexavalent chromium ions were efficiently transported from the food chamber at pH 9.0 when the 65.2% MTA1 P(ClVBTA) homopolymer IPN membrane and 48.5% MTAG P(GMA-NMG)/P(ClVBTA) IPN membrane were used. Similarly, hexavalent chromium ions were removed from the food chamber at pH 3.0 when MTAG (63.30%) and MTA1 (35.68%) were used in 1 mol·L− 1 NaCl solution as the extraction reagent.

Plasma Modified Polypropylene Membranes as the Lithium-Ion Battery Separators**supported by National Natural Science Foundation of China (Nos. 11175024, 11375031), the Beijing Institute of Graphic and Communication Key Project of China (No. 23190113051), the Shenzhen Science and Technology Innovation Committee of China (No. JCYJ20130329181509637), BJNSFC (No. KZ201510015014), and the State Key Laboratory of Electrical Insulation and Power Equipment of China (No.

To reduce the thermal shrinkage of the polymeric separators and improve the safety of the Li-ion batteries, plasma treatment and plasma enhanced vapor chemical deposition (PECVD) of SiOx-like are carried out on polypropylene (PP) separators, respectively. Critical parameters for separator properties, such as the thermal shrinkage rate, porosity, wettability, and mechanical strength, are evaluated on the plasma treated PP membranes. O2 plasma treatment is found to remarkably improve the wettability, porosity and electrolyte uptake. PECVD SiOx-like coatings are found to be able to effectively reduce the thermal shrinkage rate of the membranes and increase the ionic conductivity. The electrolyte-philicity of the SiOx-like coating surface can be tuned by the varying O2 content in the gas mixture during the deposition. Though still acceptable, the mechanical strength is reduced after PECVD, which is due to the plasma etching.

A zwitterionic zP(4VP-r-ODA) copolymer for providing polypropylene membranes with improved hemocompatibility

This work lays the focus on the use of a novel random zwitterionic copolymer, zP(4VP-r-ODA), obtained by polymerization reaction between 4-vinylpyrrolidone and octadecyl acrylate, and by the subsequent action of iodopropionic acid, in order to modify polypropylene (PP) membranes and provide them with antifouling and hemocompatible properties. Once the results of polymer characterization presented, we move onto the physico-chemical characterization of polypropylene (PP) membranes modified with zP(4VP-r-ODA) by self-assembling thermal evaporation process. Membranes are shown to efficiently resist to the adhesion of bovine-serum-albumin and lysozyme proteins, Escherichia coli and blood cells (erythrocytes, leukocytes, thrombocytes, whole blood). Along this manuscript, performances of membranes self-assembled with random copolymer before zwitterionization-P(4VP-r-ODA)-are systematically compared to those obtained with membranes modified with zP(4VP-r-ODA). Overall, this study unveils that these novel modified PP membranes hold promise as an alternate material for blood filtration.

Hydrolysis of whey lactose by immobilized β-galactosidase in a bioreactor with a spirally wound membrane

The β-galactosidase was covalently immobilized onto a modified polypropylene membrane, using glutaraldehyde. The optimal conditions for hydrolysis of lactose (4.7%) by immobilized β-galactosidase in a batch process were determined 13.6U enzyme activity, 40°C, pH 6.8 and 10h. The obtained degree of hydrolysis was compared with results received by a free enzyme. It was found, that the lactose hydrolysis by an immobilized enzyme was 1.6 times more effective than the lactose hydrolysis by a free enzyme. It was determined that the stability of the immobilized enzyme was 2 times higher in comparison with the stability of free enzyme. The obtained immobilized system β-galactosidase/polypropylene membrane was applied to produce glucose–galactose syrup from waste whey. The whey characteristics and the different preliminary treatments of the whey were investigated. Then the whey lactose hydrolysis in a bioreactor by an immobilized enzyme on a spirally wound membrane was performed. The optimal membrane surface and the optimal flow rate of the whey through the membrane module were determined, respectively 100cm2 and 1.0mLmin−1. After 10h, the degree of lactose hydrolysis was increased to 91%. The operation stability was studied. After 20th cycle the yield of bioreactor was 69.7%.

Mussel-inspired modification of Microporous polypropylene membranes for functional catalytic degradation

In this manuscript, an easy method of anchoring Au nanoparticles onto a polypropylene (PP) membrane to prepare a composite Au-PP membrane with catalytic activity was demonstrated. The surface of the PP membrane was first modified with a primary amine by mussel-inspired dopamine polymerization. Then, the modified PP membrane was used to reduce chloroauric acid to anchor Au nanoparticles onto the surface, forming a Au-PP membrane. The surface morphology and composition of the modified PP membrane were characterized with SEM, ATR-FTIR and XPS. The catalytic activity of the Au-PP membrane was also evaluated by the degradation of a model dye solution of methylene blue. The fabricated membrane shows excellent catalytic performance, and the catalytic activity can be effectively regenerated.

Ion-selective interpenetrating polymer networks supported inside polypropylene microporous membranes for the removal of chromium ions from aqueous media

The ion-exchange properties of interpenetrating polymer networks (IPNs) have been studied to provide metal-ion transport with high selectivity. Polypropylene (PP) membranes incorporating poly[(ar-vinylbenzyl) trimethylammonium chloride], P(ClVBTA), poly[2-(acryloyloxy)ethyl]trimethylammonium chloride] P(ClAETA), poly(acrylic acid) P(AA), poly(2-acrylamidoglycolic acid) P(AGA), poly(glycidylmethacrylate-N-methyl-d-glucamine) P(GMA-NMG), poly(2-acrylamido-2-methyl-1-propane sulfonic acid) P(AMPS), and poly[sodium (styrene sulfonate)], P(SSNa) were modified via an “in situ” radical-polymerization. The surface of PP was activated by a hydrophilic grafted polyelectrolyte and then pressure injection was used for impregnation of the reactive solution in the membrane. The following conditions were varied: the functional monomer, grafted polyelectrolyte, and cross-linked concentration. The modified PP membranes were characterized using SEM/EDS, FT-IR, electrokinetic potential, and Donnan dialysis for the chromium ion transport. The modified membranes exhibited hydrophilic character with a water-uptake capacity between 15 and 40 % and a percentage of modification between 2.5 and 5.5 % in comparison with the behavior of the unmodified polypropylene membrane as the blank probe. Hexavalent chromium ions were efficiently transported by the modified membranes containing P(ClVBTA) (61.2 %) and only 5.8 % of trivalent chromium were extracted at pH 3.0 using a 1 mol/L NaCl solution as the extraction reagent. Similarly, Cr(III) transport using membranes modified with P(SSNa) achieved 42.1 % extraction at pH 3.0 using 1 mol/L NaCl as the extraction reagent and 2.5 % extraction was achieved for Cr(VI). Unmodified PP membrane shows Cr(VI) extraction percentage between 1.6 and 3.1 %, and Cr(III)extraction percentage between 2.3 and 2.6 %.

Study on the fouling behavior of silica nanocomposite modified polypropylene membrane in purification of collagen protein

In this study, microporous polypropylene (PP) membrane was fabricated via thermally induced phase separation (TIPS) method. Using Stober method, hydrophilic SiO2 nanoparticles (NPs) were synthesized by in situ and ex situ approaches and covalently connected to the membrane via hydrolysis-condensation reactions with hydroxyl (OH) groups, created by Piranha solution (3:1, v/v, H2SO4 and H2O2) in pretreatment step. The average sizes of SiO2 NPs synthesized by in situ and ex situ approaches were about 250–300nm and 15–20nm, respectively. Incorporation of SiO2 NPs on the membrane surface improved surface hydrophilicity, pure water flux and mechanical properties and increased the portion of reversible fouling ratio (RFR) which consequently resulted in higher flux recovery (FR) of the membrane due to the hydrophilic property of SiO2 NPs. The flux recovery (FR) increased from 64.5% for unmodified membrane to 71.8%, 79.2% and 88.6% for PP-SiO2 composite membranes prepared by in situ and two ex situ routes with 6 and 12h immersion time intervals, respectively. Application of combined fouling models revealed that the “cake filtration-standard blockage” fouling mechanism is prevailing fouling mechanism for all membranes.

Polypropylene membranes modified with interpenetrating polymer networks for the removal of chromium ions

ABSTRACTPolypropylene (PP) membranes incorporating poly[(ar‐vinylbenzyl) trimethylammonium chloride] P(ClVBTA), and poly[sodium (styrene sulfonate)] P(SSNa) were modified via an “in situ” radical polymerization synthesis. Two methods were used for impregnation of the reactive solution: pressure injection and plasma superficial activation with argon gas. The following conditions were varied: the monomer concentrations, number of injections, and cross‐linked concentration. The modified polypropylene membranes were then characterized using scanning electron microscopy/energy dispersive X‐ray spectroscopy, Fourier transform‐infrared spectroscopy, electrokinetic potential, and Donnan dialysis for the chromium ions transport. The modified membranes exhibited a hydrophilic character with a water uptake capacity between 15% and 20% and a percent modification between 2.5% and 4.0%. This was compared with the results of an unmodified polypropylene membrane as the blank and the mentioned polypropylene membrane has not the capacity to uptake water because this kind of material is highly hydrophobic. Hexavalent chromium ions were efficiently transported by the modified membranes containing P(ClVBTA) via a plasma method and it achieved 59.2% extraction at pH 9.0 using a 1‐mol L−1 NaCl extraction agent. Therefore, unmodified polypropylene membrane shows an extraction percentage close to 10% from the hexavalent chromium ions at pH 9.0. In the same way, the trivalent chromium transport using membranes modified with P(SSNa) achieved 49.0% extraction at pH 2.0 using 1 × 10−1 mol L−1 HNO3 and 1 mol L−1 NaCl as the extraction agents. Moreover, the unmodified polypropylene membrane reached a value close to 10% from the trivalent chromium ions using 1 × 10−1 mol L−1 HNO3 and 1 mol L−1 NaCl. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41953.