Phase Separation Method Research Articles

Barrier and passivation effects of 2D PANI@JNSs Janus nanosheets in epoxy anticorrosion coating

AbstractThe filled sheet‐like inorganic materials can usually improve the anticorrosion performance of the coating. Herein, the Janus nanosheets (JNSs) with two‐dimensional structure were prepared by phase separation method, modified by polyaniline (PANI) on the amino side of JNSs and composited with epoxy resin (EP). Scanning electron microscope (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetry (TG) were used to characterize the morphology and chemical structure of JNSs and PANI@JNSs. The anti‐corrosion performance of coatings was measured by electrochemical impedance spectroscopy (EIS) and salt spray experiment. Compared with pure EP, the |Z|0.01Hz of 0.5%‐JNSs/EP coating and that of 0.5%‐PANI@JNSs/EP coating reached 5.6 × 108 and 5.4× 1010 Ω·cm2 after immersed for 35 days, nearly 2 and 4 orders of magnitude higher than pure EP respectively. The excellent anti‐corrosion performance of 0.5%‐PANI@JNSs/EP coating is due to the synergistic effect of physical barrier effect of PANI@JNSs, interfacial interaction between PANI@JNSs and epoxy resin and passivation effect of PANI. Moreover, PANI@JNSs possess both strengthening and toughening effects on composite coating. Janus nanosheets provide a new idea and method for preparing high‐performance anticorrosive materials.

Explication of polydopamine modified g-C3N4 as effective additive in PVDF nanocomposite membrane fabrication for enhanced ultrafiltration and self-cleaning performance

Nanocomposite membranes (NCMs) incorporated with nanomaterials have recently received increasing attention, but the preparation of high-performance membranes is still challenging due to the hydrophilicity and self-aggregation of the nanoparticles. In this study, graphite carbon nitride containing nitrogen defects was modified using dopamine (PDA@DCN) for effective alleviation of the agglomeration of nanoparticles resulting in a uniform casting solution. A non-solvent-induced phase separation method was adapted to prepare PVDF NCMs by using PDA@DCN as an effective additive. Superior permeability and selectivity were exhibited by the PDA0.25 @DCN/PVDF2 membrane (where a DA concentration of 0.25 g/100 mL was used in PDA@DCN preparation and 2% PVP was added during the membrane preparation) with the pure water flux of 390 L/(m2·h) and Bovine serum albumin (BSA) rejection of 95.9%. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory revealed that the improvement of the flux recovery rate of PDA0.25 @DCN/PVDF2 was due to the decreased attractive interaction for fouling. Ternary phase diagram and viscosity experiments confirmed that the addition of PDA0.25 @DCN accelerated phase inversion rate (as evident from thermodynamics and kinetics) and increased the porosity with smaller average surface pore size, which is expected to have good permeability and selectivity as an ultrafiltration membrane. Moreover, an excellent self-cleaning performance was demonstrated by PDA0.25 @DCN/PVDF2, with a flux recovery rate of 84.5%, simply under visible light irradiation, which indicates its potential for environment-friendly practical application.

Self-assembly of MOF-801 into robust hierarchically porous monoliths for scale-up atmospheric water harvesting

MOFs are becoming one of the most promising sorbents for atmospheric water harvesting (AWH), but their powder form limits the scale-up application. Conventional shaping methods tend to deteriorate the sorption performance or weaken the mechanical strength of the sorbents. Here, monolithic MOF-801 was constructed by coupling sol–gel phase separation and acid-heat post-treatment method. The porosity can be optimized up to 59.7% by regulating the phase separation progress and gelation time, and the specific surface area and micropore volume can be optimized up to 977.8 m2 g−1 and 0.234 cm3 g−1 by the acid-heat post-treatment. The special properties ensured the monolithic MOF-801 with an excellent moisture sorption capacity of 1.2 times higher than that of the conventional MOF-801 powder in small batches and 1.4 times higher than that of the conventional compressed tablet in large batches at 30% RH. The monolithic MOF-801 had centimeter-scale morphology and good mechanical strength with compressive Young's modulus up to 61.3 MPa. This study provides a feasible strategy for achieving the monolithic shaping of MOFs for industrial-scale AWH.

Preparation of Hyflon AD/Polypropylene Blend Membrane for Artificial Lung.

A high-performance polypropylene hollow fiber membrane (PP-HFM) was prepared by using a binary environmentally friendly solvent of polypropylene as the raw material, adopting the thermally induced phase separation (TIPS) method, and adjusting the raw material ratio. The binary diluents were soybean oil (SO) and acetyl tributyl citrate (ATBC). The suitable SO/ATBC ratio of 7/3 was based on the size change of the L-L phase separation region in PP-SO/ATBC thermodynamic phase diagram. Through the characterization and comparison of the basic performance of PP-HFMs, it was found that with the increase of the diluent content in the raw materials, the micropores of outer surface of the PP-HFM became larger, and the cross section showed a sponge-like pore structure. The fluoropolymer, Hyflon ADx, was deposited on the outer surface of the hollow fiber membrane using a physical modification method of solution dipping. After modification, the surface pore size of the Hyflon AD40L modified membranes decreased; the contact angle increased to around 107°; the surface energy decreased to 17 mN·m-1; and the surface roughness decreased to 17 nm. Hyflon AD40L/PP-HFMs also had more water resistance properties from the variation of wetting curve. For biocompatibility of the membrane, the adsorption capacity of the modified PP membrane for albumin decreased from approximately 1.2 mg·cm-2 to 1.0 mg·cm-2, and the adsorption of platelets decreased under fluorescence microscopy. The decrease in blood cells and protein adsorption in the blood prolonged the clotting time. In addition, the hemolysis rate of modified PP membrane was reduced to within the standard of 5%, and the cell survival rate of its precipitate was above 100%, which also indicated the excellent biocompatibility of fluoropolymer modified membrane. The improvement of hydrophobicity and blood compatibility makes Hyflon AD/PP-HFMs have the potential for application in membrane oxygenators.

Design of a mixed‐matrix polyether sulfone membrane with well self‐cleaning capability for oil/water separation

AbstractA self‐cleaning mixed‐matrix membrane was successfully developed and fabricated using the reverse thermally induced phase separation (RTIPS) method, incorporating modified particles. To achieve this, DA@CuFe2O4 particles were prepared by modifying CuFe2O4 with dopamine (DA) and then fed into the membrane matrix. The RTIPS method was employed to create hydrophilic membranes that exhibited remarkable stability and toughness. X‐ray diffraction, Fourier‐transform infrared (FTIR), transmission electron microscopy, and thermogravimetric analysis results showed that the particles were successfully modified. XPS, scanning electron microscopy, and FTIR proved that the modified particles were introduced into the film. The EDS spectra also showed that the self‐made CuFe2O4 particles with DA adsorbed on the surface were uniformly distributed in the organic matter. In addition, the results of the contact angle characterization, tensile test, water flux test, oil–water separation test, and cycle test showed that the material with a high water flux (1707.78 L/m2 h) and removal rate of >99.9% has good wettability, mechanical properties, corrosion resistance, and stain resistance. In addition, the photocatalytic performance of the modified membranes was demonstrated by studying the degradation of pollutants under visible light. Through photocatalysis, the membrane material obtained a higher utilization rate, which provided a new attempt to solve the membrane separation technology in the field of oily wastewater treatment.

Thermodynamics and kinetic analysis of membrane: Challenges and perspectives

The ultimate structure of the membrane is determined using two important effects: (i) thermodynamic effect and (ii) kinetic effect. Controlling the mechanism of kinetic and thermodynamic processes in phase separation is essential for enhancing membrane performance. However, the relationship between system parameters and the ultimate membrane morphology is still largely empirical. This review focuses on the fundamental ideas behind thermally induced phase separation (TIPS) and nonsolvent-induced phase separation (NIPS) methods, including both kinetic and thermodynamic elements. The thermodynamic approach to understanding phase separation and the effect of different interaction parameters on membrane morphology has been discussed in detail. Furthermore, this review explores the capabilities and limitations of different macroscopic transport models used for the last four decades to explore the phase inversion process. The application of molecular simulations and phase field to understand phase separation has also been briefly examined. Finally, it discusses the thermodynamic approach to understanding phase separation and the consequence of different interaction parameters on membrane morphology, as well as possible directions for artificial intelligence to fill the gaps in the literature. This review aims to provide comprehensive knowledge and motivation for future modeling work for membrane fabrication via new techniques such as nonsolvent-TIPS, complex-TIPS, non-solvent assisted TIPS, combined NIPS-TIPS method, and mixed solvent phase separation.

Polyethyleneimine-cured epoxy-based solvent tolerant nanofiltration membranes

Epoxy-based nanofiltration (NF) membranes have great potential to allow untapped applications such as the treatment of water/solvent mixtures. However, achieving reproducible membrane performance with concurrent high permeances for water/solvent mixtures and high solute rejections remains challenging. Herein, such a solvent-tolerant NF (STNF) membrane with superior performance characteristics is synthesized through optimizing the non-solvent induced phase separation (NIPS) method by simultaneously curing 2 epoxide building blocks (EPON 1009F (20 wt%) and EPON SU-8 (10 wt%)) with hyperbranched polyethylene imine (PEI) in dimethyl sulfoxide (DMSO). As a multifunctional crosslinker, the hyperbranched PEI, compared to the difunctional linear hexane diamine (HDA), increases the synthesis reproducibility, the membrane flexibility and permeability, offering a remarkable water/DMF (80/20) permeance of 5.7 L m-1 h-1 bar-1 and a rejection of rose bengal (1018 g mol−1) of 93.3%. A decreased permeance and rejection was observed when increasing the solvent content in the water/DMF or water/ethanol feed from 0 to 30 wt%, while a change in water permeance occurred before and after water/solvent filtrations. The epoxy-based membrane is also intrinsically stable in many solvents, and is easy to tune and produce, making it an ideal candidate for the purification of solvent-containing wastewaters from e.g., the pharmaceutical and chemical industries.

Flexible Z-scheme heterojunction membrane reactors for visible-light-driven antibiotic degradation and oil-water separation

This study fabricated PENS/TA/ZIF-67@Ag2S (PZA), a double self-cleaning network antifouling polymer membrane reactor, by the non-solvent-induced phase separation (NIPS) method. Due to the synergistic effect of the double self-cleaning structure, it showed an excellent separation efficiency of 99.65% and a high flux of 1198.011 L·m−2·h−1 in the separation of oil-in-water emulsion experiments. After eight cycles, Oil-water separation efficiency remains >99% recyclable. The Z-type heterogeneous conjunctival reactor we constructed has a high-efficiency degradation rate of 99.94% and a mineralization rate of 80.315% for sulfamethoxazole (SMX) within 120 min. From the results of mechanical properties, TGA and DSC, it can be seen that PZA has good strength, toughness and high temperature resistance. According to the experimental analysis of active substances, the active ingredients produced by PZA are •OH., h+, •O2–. Based on Density functional theory (DFT) calculations and intermediate analysis, sulfamethoxazole's active sites and degradation pathways (SMX) were explored. According to the Quantitative Structure-Activity Relationship (QSAR) of the Toxicity Estimation Software Tool (TEST), the toxicity of the intermediates produced during the degradation of SMX was predicted. This study provides a feasible strategy for fabricating Z-scheme metal-organic framework (MOF)-based polymer membrane reactors for efficient green antibiotic wastewater treatment and oil-water self-cleaning.

Improving waterproof-breathable capability of degradable macroporous film/hemp hydroentangled nonwovens composite membranes by porous structure and surface wettability modification

Due to recent serious COVID-19 pandemic, medical protective materials with outstanding microbial barrier and liquid barrier property have attracted much attention. However, the crucial issue of improving the waterproof-breathable capability and degradable properties of medical protective material is still challenging. In this research, poly(butyleneadipate-co-terephthalate) (PBAT)/hemp@silica-polyvinylsilsesquioxane (SiO2-PVSQ) composite membranes with good moisture permeability and waterproof property were fabricated. Firstly, hemp and cotton fibers were mixed and hemp/cotton hydroentangled nonwovens were produced to endow the membranes with outstanding water vapor penetration and mechanical properties. Then, degradable PBAT macroporous membranes were prepared by non-solvent induced phase separation (NIPS) method, and combined with hemp/cotton hydroentangled nonwovens to endow the composite membranes with waterproof property. Finally, SiO2 particles were hydrophobically modified by vinyltrimethoxysilane (VTMOS) and grafted on the surface of PBAT/hemp composite membranes. The waterproof property of composite membranes was further improved by hierarchical rough structure and low surface tension hydrophobic groups on the membrane surface. The prepared PBAT/hemp@SiO2-PVSQ composite membranes showed excellent tensile strength with high moisture permeability, good waterproof and water contact angle of 139.5°, indicating promising candidates for the new generation comfort and degradable medical protective textiles.

Three-Dimensional Scaffolds for Bone Tissue Engineering.

Immobilization using external or internal splints is a standard and effective procedure to treat minor skeletal fractures. In the case of major skeletal defects caused by extreme trauma, infectious diseases or tumors, the surgical implantation of a bone graft from external sources is required for a complete cure. Practical disadvantages, such as the risk of immune rejection and infection at the implant site, are high in xenografts and allografts. Currently, an autograft from the iliac crest of a patient is considered the "gold standard" method for treating large-scale skeletal defects. However, this method is not an ideal solution due to its limited availability and significant reports of morbidity in the harvest site (30%) as well as the implanted site (5-35%). Tissue-engineered bone grafts aim to create a mechanically strong, biologically viable and degradable bone graft by combining a three-dimensional porous scaffold with osteoblast or progenitor cells. The materials used for such tissue-engineered bone grafts can be broadly divided into ceramic materials (calcium phosphates) and biocompatible/bioactive synthetic polymers. This review summarizes the types of materials used to make scaffolds for cryo-preservable tissue-engineered bone grafts as well as the distinct methods adopted to create the scaffolds, including traditional scaffold fabrication methods (solvent-casting, gas-foaming, electrospinning, thermally induced phase separation) and more recent fabrication methods (fused deposition molding, stereolithography, selective laser sintering, Inkjet 3D printing, laser-assisted bioprinting and 3D bioprinting). This is followed by a short summation of the current osteochondrogenic models along with the required scaffold mechanical properties for in vivo applications. We then present a few results of the effects of freezing and thawing on the structural and mechanical integrity of PLLA scaffolds prepared by the thermally induced phase separation method and conclude this review article by summarizing the current regulatory requirements for tissue-engineered products.

Efficient Passive Daytime Radiative Cooling by Hierarchically Designed Films Integrating Robust Durability.

Surfaces with efficient passive daytime radiative cooling (PDRC) are underpinned by maximizing both solar reflection and thermal radiation to the outer space at no additional energy cost. Despite notable progress, their practical applications are of great challenge due to their complicated fabrication processes, easy contamination and damage, and high costs. Herein, we fabricate a hierarchically designed passive daytime radiative cooling film (HPRF) comprising cost-effective Al2O3 particles and poly(dimethylsiloxane) (PDMS) via a simple phase separation method. The designed film possesses a high solar spectrum reflectance of ∼0.96 and a mid-infrared emittance of ∼0.95, achieving a ∼12.4 °C subambient cooling under direct solar irradiation. This excellent PDRC is due to the efficient Mie scattering of sunlight by hierarchical micro-/nanostructures and selected molecular vibrations of PDMS combined with the phonon polariton resonance of Al2O3 particles, respectively. Moreover, the designed HPRF is accompanied with robust durability endowed by superior self-cleaning, flexibility, and anti-ultraviolet radiation that can present substantial application promises of thermal management in various electronic devices and wearable products.

Deciphering molecular mechanisms of phase separation in RNA biology by single-molecule biophysical technologies.

Ribonucleic acid (RNA) biology has emerged as one of the most important areas in modern biology and biomedicine. RNA and RNA-binding proteins (RBPs) are involved in forming biomolecular condensates, which are crucial for RNA metabolism. To quantitively decipher the molecular mechanisms of RNP granules, researchers have turned to single-molecule biophysical techniques, such as single-molecule Förster resonance energy transfer (smFRET), in vivo single-molecule imaging technique with single particle tracking (SPT), DNA Curtains, optical tweezers, and atomic force microscopy (AFM). These methods are used to investigate the molecular biophysical properties within RNP granules, as well as the molecular interactions between RNA and RBPs and RBPs themselves, which are challenging to study using traditional experimental methods of the liquid-liquid phase separation (LLPS) field, such as fluorescence recovery after photobleaching (FRAP). In this work, we summarize the applications of single-molecule biophysical techniques in RNP granule studies and highlight how these methods can be used to reveal the molecular mechanisms of RNP granules.

Energy saving phase change energy storage thermochromic liquid crystal display

Phase change energy storage microcapsules (PCESM) improve energy utilization by controlling the temperature of the surrounding environment of the phase change material to store and release heat. In this paper, a phase change energy storage thermochromic liquid crystal display (PCES-TC-LCD) is designed and prepared for the first time. The as-prepared PCES-TC-LCD has a stable bilayer structure, where the lower layer is a thermochromic LC layer produced by centrifugal spin coating and high temperature curing, and the upper layer is a polymer-stabilized liquid crystal (PSLC) film with phase change energy storage properties obtained by polymerization-induced phase separation method. The prepared PCES-TC-LCD can realize the functions of triple-field driven and phase change energy storage, which has strong research value. In the performance experiments, the electro-optical properties of PCES-TC-LCD were analyzed and optimized by three sets of experiments on liquid crystal content, polymerization time, and PCESM content. In the film formation study, PCES-TC-LCD based on rigid/flexible substrates were prepared, respectively. The phase change energy storage function of PCES-TC-LCD was performed by differential scanning calorimetry (DSC) and infrared thermography. The devices formed on rigid or flexible substrates with stable phase change energy storage performance, which has great application value by reducing the external energy input, prolonging the thermochromic time and achieving energy saving effects.

Synthesis of Porous MgF2 Coating by a Sol–Gel Method Accompanied by Phase Separation

Surfaces with translucent and wear-resistant effects have a wide range of applications, especially as protective layers. In this work, a simple and convenient method for the preparation of porous magnesium fluoride (MgF2) coatings was proposed. Nano-porous MgF2 powder was prepared with sol–gel and phase separation methods by optimizing the polymer amount and used for the preparation of thick layers onto PVC substrates. The automated surface area and porosity analyzer (BET) and scanning electron microscopy (SEM) confirmed that the layers containing 0.028‰ PEO presented a 3D structure with pore sizes in the range of 16 nm. The layer reached 93% transmittance in the visible region, a Vickers hardness value of 2889.1 kg/mm2, and a friction coefficient of 0.2 in the wear test.

Role of natural deep eutectic solvents (NADESs) in coagulation bath for PVDF-based membranes on enhanced permeation and separation of rare earth ions

Efficient separation of single rare earth element such as neodymium (Nd) has become an important research topic due to the supply crisis which seriously restricts the application and promotion of rare earth permanent magnets. PVDF-based separation membranes prepared by non-solvent induced phase separation (NIPS) method usually exhibited hydrophobic surface properties resulting in performance attenuation and operation cost increase. This article applied an easily available NADES from betaine and lactic acid to regulate and control the coagulation bath of a polymer inclusion membrane (PIM) for the separation of Nd, Sm and Dy ions. Evidences for the formation of DES were characterized via 1H NMR and FT-IR, and betaine showed more obvious changes than lactic acid during the formation of DES via hydrogen bonds. With the help of DES, pores on the surface were much larger and richer, and the migration of PO and P–O groups to the lower epidermal layer of the membrane made the surface layer become more hydrophilic. DES accelerated the liquid-liquid demixing process and led to faster membrane-forming speed and typical finger-like macrovoids and short vertical penetration channels, which could be observed at high DES contents, and a DES content of 5 wt% was found the most optimal considering the overall permeability and separation performances. As an effective means to improve membrane's performances, adding hydrophilic NADESs at a proper ratio in the coagulation bath would be conducive to form more porous structures, higher surface hydrophilicity, optimized permeability and separation performances.

Self-Cleaning and Photodegradable PVDF-g-IL Dye Wastewater Separation Membranes Modified with Dopamine-Coated TiO2 Core-Shell Particles.

In the present work, self-cleaning membranes of ionic liquid-grafted poly(vinylidene fluoride) (PVDF) polydopamine-coated TiO2 were prepared through a nonsolvent-induced phase separation method. PDA facilitates the uniform dispersion of TiO2 nanoparticles in PVDF substrates; meanwhile, TiO2@PDA core-shell particles and the hydrophilic IL improve the hydrophilicity of PVDF membranes and contribute to the increased average pore size and porosity, significantly improving the pure water permeation flux and dye wastewater flux (the water flux increased to 385.9 Lm-2 h-1). In addition, the combined effect of the positively charged IL and the strongly viscous PDA shell layer enhanced the retention and adsorption of dyes so that the retention and adsorption rates of both anionic and cationic dyes were close to 100%. Notably, the hydrophilic PDA allowed more TiO2 to migrate to the membrane surface during the phase transition; on the other hand, dopamine could promote photodegradation. Therefore, the combined two factors for TiO2@PDA were beneficial to the ultraviolet-catalytic (UV-catalytic) degradation of dyes on the surface of the membrane, leading to >80% degradation rates of various dyes. Thus, the high-efficiency and easy-to-operate wastewater treatment technology provides attractive potential for dye removal and resolution of membrane contamination.

Controllable growth of porous morphology in low dielectric polyimides via thermal-driven spontaneous phase separation

Fabricating porous polymer films with precise morphological control via a conventional phase separation method is challenging. Herein, porous polyimide (PPI) film formation kinetics was thoroughly investigated to understand the underlying phenomena during the thermally induced phase separation. The porous films were prepared using a poly(amic acid) (PAA) solution with a small-molecular phase dispersion agent (i.e., porogen), dibutyl phthalate (DBP), which is miscible with the PAA chains. Using amine-functionalized polyhedral oligomeric silsesquioxane (NH2-POSS) as an additional nucleating agent, sponge-like NH2-POSS end-capped PPI (PPI/NH2-POSSx) films were fabricated with tunable pore size (16.3–76.9 μm) and porosity (42.6–69.4 %). This ensured control over the porous structure of the PPI/NH2-POSSx film, providing desirable low dielectric properties (a minimum of 2 at 1 MHz) in broad frequency and temperature range as well as high thermal stability (Tg = 363–385 °C, T5% = 519–559 °C), and good mechanical strength (17–23 MPa). It was found that the porous structure and physical properties of the PPI/NH2-POSSx films can be readily engineered by tailoring the initial content of a removable porogen and cage silsesquioxane. This work will provide a new perspective on fabricating temperature-resistant low-dielectric porous polymer films with tunable pore sizes via thermal-driven spontaneous phase separation with efficient processability.

Improving the Blood Compatibility and the Gas Permeability of Polyether Ether Ketone Hollow Fiber Membrane Used for Membrane Oxygenator via Grafting Hydrophilic Components

As the core component of extracorporeal membrane oxygenation (ECMO) therapy for patients with severe cardiopulmonary failure, the structures and the properties of membrane oxygenator play a crucial role in determining both the efficiency of the gas exchange and the safety of the patients. Herein, with the aim of enhancing the blood compatibility, gas permeability, and durability of the membrane oxygenator, a porous polyether ether ketone hollow fiber membrane (PEEK-HFM) was prepared via a combination of melt spinning and thermally induced phase separation method. Subsequently, three different hydrophilic components including a nonionic polymer (poly(ethylene glycol), PEG), an ionic monomer (acrylic acid, AA), and a zwitterionic monomer (2-methacryloyloxyethyl phosphorylcholine, MPC) were introduced onto the PEEK-HFM surface by UV-induced grafting. The effects of different hydrophilic modifications on the surface characteristics (such as surface water wettability, surface potential, and porous morphologies) and the related properties (including mechanical performance, blood compatibility, and gas exchange permeability) were studied in detail. After grafting different hydrophilic components, not only the pore size of the corresponding PEEK-HFMs decreased compared to the unmodified PEEK-HFMs but also the surface roughness. Meanwhile, although the hydrophilic modifications resulted in the deterioration of the tensile strength of resulting PHFMs, it enhanced the blood compatibility of modified PEEK-HFMs. Moreover, among these modified membranes, the one grafted with MPC showed the best blood compatibility due to its more hydrophilic surface. Additionally, the modified membranes still maintained excellent gas permeability, ensuring the gas exchange performance between carbon dioxide and oxygen. Furthermore, a comprehensive comparison between the modified PEEK-HFMs and a commercial membrane oxygenator (poly(4-methyl-1-pentene), PMP) demonstrated that the modified PEEK-HFMs exhibited higher gas permeability, better blood compatibility, stronger gas exchange ability, and comparable tensile strength, indicating their potential as a high-efficiency option for membrane oxygenators.

Preparation of polydopamine-functionalized polyamidoxime membrane for uranium recovery from seawater

A stable supply of uranium resources is essential to the sustainable development of nuclear energy. Extraction of uranium from seawater or uranium-containing wastewater with abundant uranium reserves has attracted much attention. Here, a polydopamine-functionalized polyamidoxime membranes (PDA@PAO membranes) were fabricated via nonsolvent induce phase separation method coupling with polymerization deposition process of dopamine and further applied to capture U(VI) from solution. The PDA@PAO membranes exhibited impressive adsorption capacity and convenient separation from solution. The adsorption kinetics and equilibrium adsorption of PDA@PAO membranes satisfactorily fitted with the pseudo-second-order model and the Langmuir model, respectively. The maximum adsorption capacity for uranium calculated according to the Langmuir model at pH 5.00 and 298 K reached 730 mg·g−1. Moreover, the adsorption capacity of the PDA@PAO membranes was maintained at 212 mg·g−1 under the interference of 9 different kinds of competing ions and the removal of U(VI) all reached more than 90 % in three different concentrations of uranium-spiked natural seawater, which revealed that the adsorbent possessed the promising selectivity for uranium. In addition, the PDA@PAO membranes exhibited satisfactory reusability, and the uranium adsorption capacity and desorption rate were maintained above 96.5 % after five adsorption–desorption cycles. The high capacity, excellent selectivity and good reusability endow PDA@PAO membranes as a suitable candidate for the extraction of U(VI) from actual industrial wastewater or seawater.

Influence of particle size on electrorheological effect of poly(ionic liquid) microsphere suspensions

Hydrophobic poly(ionic liquid) microspheres with different sizes are prepared via cooling assisted phase separation method. The morphology and structure of microspheres are characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The effect of particle size on the electrorheological effect of the poly(ionic liquid) microsphere suspensions is studied by rheological test under electric fields. It shows that the shear stress at zero electric field decreases with the increase of particle size, while yield stress and electric field-induced shear stress increase with the increase of particle size. The electric field dependence of yield stress and electric field-induced shear stress increment is independent of particle size.