Modified Phase Inversion Research Articles

Optimal conditions for nano-emulsified vegetable oil synthesis for the biostimulation of 1,1,2-trichloroethane and vinyl chloride contaminated groundwater in bioreactors

Contamination of groundwater with chlorinated aliphatic hydrocarbons (CAHs) has become increasingly widespread. Enhanced reductive dechlorination (ERD) by emulsified vegetable oil (EVO) is an environmentally friendly, low-carbon and sustainable technology that effectively eliminates the threat from CAHs. To improve the permeability and bioavailability of EVO in the low-permeability substratum, nano-emulsified vegetable oil (nanoEVO) can be synthesized using a modified phase inversion composition method (MPIC) by increasing the emulsification temperature that reduces the shear force required for the formation of nanodroplets and the interfacial tension between the mixed phase and water. The emulsification temperature of 60 °C, the water content of 40–70%, the droplet diameter (DD) of nanoEVO prepared by MPIC is ∼200 nm, and had good monodispersion (≤0.2). The high molecular weight and low solubility of vegetable oil, and similar size of droplet make nanoEVO remains homogeneous after storage for > one year. NanoEVO can effectively biostimulate indigenous bacteria in CAHs-contaminated groundwater to dechlorinate 1,1,2-trichloroethane (1,1,2-TCA) to ethene via vinyl chloride (VC). The maximum dihaloelimination rate of 1,1,2-TCA was ∼66.06 μM·Cl−·day−1 and the maximum hydrogenolysis rate of VC was ∼35.67 μM·Cl−·day−1. NanoEVO effectively increased the relative abundance of Dehalococcoides from <0.10 to 9.61%. The abundances of Dhc 16S rRNA gene and dehalogenase gene vcrA increased by 102 and 103, respectively. Biostimulation shaped the structure of microbial communities and promoted hydrolytic acidification and anaerobic fermentation. Moreover, the syntrophic VFA-oxidizing bacteria participated in secondary fermentation and were closely correlated with H2 consumption metabolism. By providing carbon sources and maintaining an anaerobic environment with stable pH and ORP, nanoEVO biostimulated the hydrolytic acidification led by fermentative bacteria, secondary fermentation with syntrophic VFA-oxidizing bacteria and reductive dechlorination carried out by dechlorinator, thus greatly increasing the CAH-dechlorinating ability of indigenous microbial communities.

Preparation of PLGA Microspheres Using the Non-Toxic Glycofurol as Polymer Solvent by a Modified Phase Inversion Methodology.

Poly(D,L-lactide-co-glycolide is a biodegradable copolymer that can release pharmaceuticals. These pharmaceuticals can provide local therapy and also avert the clinical issues that occur when a drug must be given continuously and/or automatically. However, the drawbacks of using poly(D,L-lactide-co-glycolide include the kinetics and duration of time of poly(D,L-lactide-co-glycolide drug release, the denaturing of the drug loaded drug, and the potential clinical side effects. These drawbacks are mainly caused by the volatile organic solvents needed to prepare poly(D,L-lactide-co-glycolide spheres. Using the non-toxic solvent glycofurol solvent instead of volatile organic solvents to construct poly(D,L-lactide-co-glycolide microspheres may deter the issues of using volatile organic solvents. Up to now, preparation of such glycofurol spheres has previously met with limited success. We constructed dexamethasone laden poly(D,L-lactide-co-glycolide microspheres utilizing glycofurol as the solvent within a modified phase inversion methodology. These prepared microspheres have a higher drug load and a lower rate of water diffusion. This prolongs drug release compared to dichloromethane constructed spheres. The glycofurol-generated spheres are also not toxic to target cells as is the case for dichloromethane-constructed spheres. Further, glycofurol-constructed spheres do not denature the dexamethasone molecule and have kinetics of drug release that are more clinically advantageous, including a lower drug burst and a prolonged drug release.

Development of polyethersulfone/polylactic acid‐blended nanocellulose membranes for enhanced removal of methylene blue dye

AbstractHerein, adsorptive polyethersulfone/polylactic acid (PES/PLA) blends membranes with systematic concentrations of cellulose nanofibers (CNFs) (0.5–2.5 wt%) were developed via a modified phase inversion process for the enhanced removal of cationic methylene blue (MB) dye. To the best of our knowledge, this is the first time that such adsorptive membranes have been produced for potential use in wastewater treatment. The fabricated membranes were characterized for surface and cross‐sectional morphology (scanning electron microscope), surface roughness (atomic force microscope), functionality (Fourier‐transform infrared spectroscopy), thermal stability (thermal gravimetric analysis), wettability (contact angle measurements), antifouling behavior (flux recovery studies), and dye adsorption and reusability (adsorption and desorption tests). CNF incorporated membranes showed improved wetting properties, with contact angle decreasing from 76° in the pristine membranes to 48° in 2.5 wt% PES/PLA membranes. The membrane bulk porosity increased from 60.3% to 79.23%, while the pure water flux increased from 210.8 to 399.12 Lm−2 h−1. At optimal conditions, CNF‐modified membranes removed &gt;98% of MB compared with 8% removal by the pristine membranes. After five cycles of adsorption and desorption, the membrane with 2 wt% CNFs achieved over 70% dye removal showing excellent reusability properties. Adsorption followed pseudo‐second‐order and Freundlich models. The adsorption was attributed to electrostatic interactions between the negatively charged membrane surfaces and the positively charged dye molecules as well as through hydrogen bonding. Therefore, this work revealed that CNF‐modified PES/PLA membranes can be used as adsorbents for the enhanced removal of organic pollutants in water treatment applications.

Facile Preparation of PVDF/CoFe2O4-ZnO Hybrid Membranes for Water Depollution.

In this investigation, CoFe2O4-PVDF and CoFe2O4-ZnO-PVDF hybrid membranes were prepared using a modified phase inversion method in which a magnetic field was applied during the casting process to ensure a uniform distribution of nanomaterials on the membrane surface. Thus, better absorption of light and increased participation of nanoparticles in the photodegradation process is ensured. The influence of nanomaterials on the crystalline structure, surface morphology, and hydrophilicity properties of the PVDF membrane was investigated. The obtained results indicated that the hybrid membrane exhibited significant differences in its intrinsic properties due to the nanomaterials addition. The hydrophilicity properties of the PVDF membrane were improved by the presence of nanoparticles. The photocatalytic decomposition of aqueous Rhodamine B solution in the presence of the prepared membrane and under visible light irradiation was tested. The hybrid membrane containing CoFe2O4-ZnO on its surface exhibited a high removal rate.

Rational design of a functional interlayer to simultaneously suppress lithium polysulfides shuttling and facilitate Li-ion migration for high-performance Li-S battery

Lithium-sulfur (Li-S) battery has been considered to be the most promising next-generation secondary battery system, but the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox kinetics of LiPSs conversion processes still hinder its commercial application. Herein, a honeycomb-like structured and dense layer coated interlayer with Co nanoparticles uniformly dispersed was fabricated via a modified phase inversion method followed by carbonization. This interlayer can suppress the LiPSs shuttling by physically blocking the diffusion of LiPSs and chemically capturing and accelerating the conversion of LiPSs due to the high catalytic activity of Co nanoparticles. Meanwhile, the abundant lithiophilic pyridinic N sites can also facilitate Li+ migration, which further promotes the reaction kinetics of LiPSs conversion. Consequently, the Li-S battery assembled with this interlayer can exhibit an excellent specific capacity of 586.6 mAh/g after 400 cycles at 4.0 C with a low decay rate of 0.10 %. Even when the sulfur loading is elevated to 5.1 mg cm−2, this battery can still maintain the specific capacity of 646.0 mAh/g after 100 cycles at 0.2 C. This work demonstrates the importance and potential of the rational design of interlayer structure and composition in improving the overall Li-S battery performance.

Poly(ether ether ketone) Conferred Polyolefin Separators with High Dimensional Thermal Stability for Lithium-Ion Batteries.

The traditional polyolefin separators used in lithium-ion batteries (LIBs) are plagued by limitations such as poor wetting of electrolytes and insufficient thermal stability, hindering the progress of LIBs. To overcome these limitations, we have developed a modified phase inversion technique to efficiently and durably coat polyolefin separators with poly(ether ether ketone) (PEEK). The resulting PEEK-coated polyolefin separators exhibit mechanical properties similar to those of unmodified polyolefin separators, with comparable tensile strength and modulus. Furthermore, the PEEK coating provides outstanding thermal stability, as the modified separators maintain their stability even at temperatures up to 200 °C, which is among the best results reported for polyolefin-based separators. In addition, the PEEK coating enhances ionic conductivity by more than 100% compared to polyolefin counterparts, leading to significant improvement in the electrochemical performance of prototype half cells. The modified phase inversion technique presented here offers a practical solution for coating polyolefin separators with functional polymers, paving the way for next-generation separator materials.

Enhanced adsorptive removal of As(V) ions in aqueous solution using polyethersulfone ultrafiltration mixed matrix membranes impregnated with 3‐aminopropyltriethoxysilane modified magnetite Fe3O4 nanoparticles

AbstractThis study involves the fabrication of mixed matrix membranes (MMMs) for ultrafiltration, which contained 3‐aminopropyltriethoxysilane modified magnetite iron oxide nanoparticles (A‐Fe3O4 NPs), through a modified phase inversion technique. The physiochemical properties and surface morphologies of both the as‐synthesized A‐Fe3O4 NPs and fabricated MMMs were examined using advanced characterization techniques. The quasi‐spherical A‐Fe3O4 NPs had an average particle size of 12 nm and a Brunauer–Emmett–Teller surface area of 131.38 m2/g. Analysis by Fourier transform infrared and Raman spectroscopy confirmed the presence of NH2 and OH functional groups grafted onto the Fe3O4 NPs. The incorporation of higher loadings of A‐Fe3O4 NPs in the membrane matrix significantly improved the adsorptive ability and hydrophilicity of the adsorbent, leading to improved membrane water permeance, adsorption rate, and adsorption‐filtration properties. The water contact angle decreased from 70.7° to 63.2°, and the flux increased from 239.9 to 443.8 L/m2.h, while overall membrane porosity increased from 43.4% to 51.9%.

Green synthesis of polyvinyl-alcohol-montmorillonite clay cation exchange membrane for alkaline direct methanol fuel cell

The present study looked into a sustainable approach for synthesizing sodium ion conducting cation exchange membrane, in addition to addressing the methanol permeability, ionic conductivity, and cost of the direct methanol fuel cell (DMFC). The polyvinyl alcohol (PVA)-based sodium ion conducting membranes were synthesized by the sustainable modified phase inversion technique using a green nonsolvent coagulation bath composed of sodium hydroxide and sodium sulfate. Alkaline medium operating sulfonated polyvinyl alcohol (SPVA)-montmorillonite clay (MMT) was developed to overcome the drawbacks of a proton exchange membrane working in an acidic medium and an anion exchange membrane used in an alkaline medium. The SPVA-MMT membrane exhibited ionic conductivity of 0.0751 S cm−1 due to the presence of inorganic salts in the coagulation bath and the cation exchange capacity of the clays. Passive alkaline DMFC studies conducted using SPVA-MMT membrane showed a peak power density of 7.51 mW cm−2 at ambient conditions.

Performance evaluation of passive alkaline direct methanol fuel cell-the effect of inorganic salt and TiO2 nano fillers

In order to address the shortcomings of proton exchange membrane operating in an acidic medium and anion exchange membrane using in an alkaline medium, the present study investigated the synthesis of polyvinyl alcohol-based sodium ion conducting membrane working in an alkaline medium for the direct methanol fuel cell. The merits of the alkaline medium and cation exchange membrane are exploited by the sodium ion conducting membrane developed for alkaline direct methanol fuel cells. Poly vinyl alcohol -titanium dioxide sodium ion conducting membrane is prepared by modified phase inversion technique using the salt solution as the non-solvent in the coagulation bath. The ionic conductivity, methanol permeability, and V-I characteristics of the cation exchange membrane were studied under ambient conditions. The performance of the poly vinyl alcohol -titanium dioxide membrane is studied in a passive direct methanol fuel cell, and it is compared with the Nafion 117/Na+ membrane and poly vinyl alcohol-based anion exchange membrane. Single cell assembly with poly vinyl alcohol -titanium dioxide membrane showed a 17.14 % increase in the power density as compared to Nafion 117/Na+ membrane and a 72.77 % increase as compared to poly vinyl alcohol-based anion exchange membrane operating in the alkaline environment under ambient conditions.

Externally self-supported metallic nickel hollow fiber membranes for hydrogen separation

Highly-asymmetric metallic Ni hollow fiber membranes (NHFMs) with a dense inner skin layer and an outer porous substrate were fabricated by a modified phase inversion and sintering technique. A triple-orifice spinneret was used for spinning the hollow fiber precursors with water as the internal coagulant and a solvent-ethanol mixture as the temporary external coagulant. The hollow fiber precursors were sintered in a H2-containing atmosphere at 1100–1400 °C to form dense metallic membranes. Effects of the external coagulant composition and air gap length as well as the sintering temperatures on the morphology of the resultant hollow fiber membranes were systematically investigated. Results indicate that the hollow fiber with an optimal microstructure has achieved a maximum hydrogen flux of 73.17 mmol m−2 s−1 (9.83 mL cm−2 min−1) at 1000 °C, which is about 8 times higher than that obtained from the traditional hollow fiber membrane.

Improving hydraulic permeability, mechanical properties, and chemical functionality of cellulose acetate-based membranes by co-polymerization with tetraethyl orthosilicate and 3-(aminopropyl)triethoxysilane

Composite cellulose acetate (CA) membranes are widely used but their multiphase nature results in additive losses, poor mechanical strength, low chemical resistance and thermal stability, limiting their separation/purification yields. To overcome this, we fabricated monophasic hybrid membranes using a modified phase inversion technique, where tetraethylorthosilicate and 3-(aminopropyl)triethoxysilane were added to the CA casting solution. The resulting co-polymerization between CA, silanols and amine-functionalized silica groups, through sol-gel chemistry, was proved by ATR-FTIR (1118 cm−1, ν(SiOC)). The presence of propyl-amine groups increases the hydraulic permeability (3×), the rupture elongation (×1.5), and decreases the Young modulus (×1/2), due to the disruption of the CA-silica 3D network. For high propyl-amine contents this behaviour is reversed due to intensive cross-linking between CA-silica chains (decrease in 903 cm−1, ν(CH3COOC-)). The addition of silica- and amine-based structures to the CA framework increases the system degrees of freedom, opening the door to the design of new CA membranes.

Micro-patterned membranes prepared via modified phase inversion: Effect of modified interface on water fluxes and organic fouling

The introduction of patterns on a membrane-solute interface has been suggested as an effective method to tackle the reduced flux and fouling issues. Herein, the effectiveness of using spray-modified non-solvent induced phase separation (s-NIPS) to create a variety of micrometer-level structured interfaces is now studied. Circular, triangular and rectangular patterns with different dimensions were successfully created on polyacrylonitrile membranes. The rectangular pattern height was varied from 500 to 1500 µm, which resulted in a proportional increase in clean water permeance from 590 ± 47 L m−2 h−1 bar−1 to 1345 ± 108 L m−2 h−1 bar−1 respectively. This coincided with some BSA rejection loss for the highest patterns, indicating the fragile nature of these tall features. No significant rejection losses were found for the smaller pattern heights (145–250 µm) as compared to flat membranes, while fluxes more than doubled still. The critical pressure was also increased substantially for patterned membranes and showed a proportionality with the pattern height. These experimental findings were correlated with the reduced foulant adhesion due to a shear-induced slip boundary layer at the membrane-solution interface. Computational fluid dynamics simulations further showed higher shear stress values due to flow constriction within the membrane’s valley regions. These findings indicate the high potential of s-NIPS patterned membranes in long-term industrial applications by requiring less membrane area for a given application and reducing cleaning interventions.

Templated preparation of hierarchically porous nitrogen-doped carbon electrode material via a mild phase inversion route for high-performance supercapacitor

• Hierarchically porous nitrogen-doped carbon was prepared through a modified phase–inversion method. • Water vapor treatment induced the formation of mesopores in the whole carbon matrix. • Well-distributed macropores with uniform sizes were formed by using PVDF-HFP template. • The hierarchically porous structure and proper doping level endow the product with high and stable capacitive performances. By using poly (vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) as the template, a kind of nitrogen-doped carbon monolith with well-distributed hierarchical pores was prepared through a modified phase–inversion method. Due to the hierarchically porous structure and proper doping level, the synthesized electrode material delivered superior specific capacitances (312.2 F g −1 at 0.5 A g −1 and 217.6 F g −1 at 20 A g −1 ), as well as remarkable specific energy and power (7.1 Wh kg −1 at 250 W kg −1 ). More significantly, its high chemical and structural stability allow it to reach 109.7% of the original capacitance after 10,000 charge-discharge cycles at the current density of 20 A g −1 . The simple yet efficient synthetic strategy, unique porous structure, and thus the enhanced electrochemical capacitive performances of the prepared nitrogen-doped carbon not only make it a promising electrode material for energy storage devices, but also bring new ideas for the controllable preparation of polymer-derived hierarchically porous carbon materials. By using PVDF-HFP as the macropore template, nitrogen-doped carbon electrode material with hierarchically porous structure was prepared through non-solvent induced phase inversion process for high performance supercapacitors.

Performance control of dead-end tubular membranes fabricated with a modified phase inversion casting method

A modified phase inversion casting method is employed for the formation of dead-end tubular membrane shape in a single step. Ce0.9Gd0.1O1.95-δ (CGO)-Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) composites are applied as the membrane material. Performance of the membrane is optimised by adjusting the processing conditions in the fabrication process. Long finger-like channels, which were found to promote oxygen permeation flux without decrease of the membrane mechanical strength, were obtained in the dead-end tubes by adjusting the ceramic loadings of the casting slurries. Slurries with lower viscosity provided reduced resistance for the channel growth during the phase inversion in water. The performance of the dual-phase membranes with varied CGO:BSCF ratios were compared. The membranes containing more BSCF show higher oxygen permeation fluxes with helium as sweep gas. It was also verified that CGO content played an important role in enhancing the mechanical strength of the CGO-BSCF membranes.

Preparation of patterned flat-sheet membranes using a modified phase inversion process and advanced casting knife construction techniques

High fluxes and low fouling are practically highly desired in all membrane processes. One generic way to realize this is by introducing surface patterns on the membrane to increase the active area and the surface roughness. A new method to prepare flat-sheet patterned membranes using a patterned knife combined with a modified phase inversion process is now presented. After casting the polymer solution, the patterned knife shapes the top surface into the desired pattern. Non-solvent is sprayed immediately after the passage of the knife to rapidly solidify the polymer and preserve the pattern. To construct the patterned knife, different materials and techniques were evaluated: (1) an aluminium knife shaped by electrical discharge micromachining, (2) a gypsum knife shaped by powder-based 3D-printing, and (3) an acrylate resin, shaped by photopolymerization 3D-printing (stereolithography). As such, replacing the conventional non-solvent contact in the phase inversion via immersion by spraying already increased membrane permeance, but a significant further increase of permeance resulted from the increased surface area realized through the patterning. A minimum viscosity of the casting solution of around 7.5–10 Pa.s was required to realize well-pronounced patterns on the membrane, as screened for polyacrylonitrile and cellulose acetate, both dissolved in dimethyl sulfoxide and using water as non-solvent.

Development of double porous poly (ε - caprolactone)/chitosan polymer as tissue engineering scaffold.

Polymer blend made from poly(ε - caprolactone)/chitosan (PCL/CHT) offers interesting opportunities for biological applications. The paper presents a new way to fabricate PCL/CHT double-porosity (macrovoids with interconnected microporosity) membrane materials from a chemical optimization of the solvent and non-solvent phases and from a modified phase inversion technique. By varying the PCL/CHT proportion, it is shown that it is possible to improve the chemical and physical properties of the CHT carbohydrate polymer. The PCL/CHT membranes are fully characterized in term of physico-chemical properties (ATR-FTIR, XRD and DSC) to understand the miscibility of the two-polymer blend. Morphological characterization by SEM shows that by increasing CHT wt% in the blend, the size of the macrovoids was increasing. Rapid enzymatic degradation of PCL from all the blend was found by using lipase (from P. cepacia). The mechanisms at the origin of the morphological structuration of the material is also discussed. To test the ability to operate these materials as small diameter vascular scaffolds, cell culture with human umbilical vein endothelial cells (HUVECs) were carried out on the membrane and the results analyzed with laser scanning confocal microscopy (LSCM). Data suggest that the blend membrane with higher concentration of CHT polymer wt% have suitable properties that promote high number of cells on the surface by maintaining cellular cytoskeleton integrity within 3 days. The blend membrane with a double porous morphology could be potentially applicable in future for small diameter vascular graft application. The surface macrovoids (20-90 μm) could be useful for three-dimensional cellular adhesion and proliferation and interconnected microporous spongy network (7-20 μm) is expected to transfer essential nutrients, oxygen, growth factor between the macrovoids and the supernatant.

Three-dimensional graphene network deposited with mesoporous nitrogen-doped carbon from non-solvent induced phase inversion for high-performance supercapacitors

Three-dimensional graphitic carbon materials with controllable composition and hierarchically porous structure are promising electrode materials for supercapacitors. In this work, a modified phase inversion method combined with a calcination process was developed to prepare three-dimensional graphene networks embedded with nitrogen-doped carbon nanoparticles. When used as electrode for supercapacitors, the as-prepared material delivered a high capacitance of 431.9 F g−1 at 0.1 A g−1 and 156.8 F g−1 at 20 A g−1, as well as a stable cyclic behavior with no capacitance decay after 5000 cycles. Such a remakable capacitive performance was attributed to its hierarchically porous structure and proper nitrogen doping content (9.68 ± 0.24 at%), which facilitated the migration of electrolyte ions and provided abundant redox active sites for the faradic reactions. The synthetic strategy may be exploited for the rational design and synthesis of new carbon materials with controlled doping level and three-dimensional porous structure.

Fabrication and Characterization of Microtubular Solid Oxide Cell Supported with Nanostructured Mixed Conducting Perovskite Fuel Electrode

Mixed ionic and electronic conducting (MIEC) perovskites demonstrate advantages over Ni-cermet as fuel electrode materials for solid oxide cells (SOCs). However, SOCs are primarily electrolyte-supported planar designs in literature when MIEC perovskite fuel electrodes are employed, which are relatively easy to fabricate but usually have high electrolyte ohmic resistance. Perovskite fuel electrode-supported designs are rarely studied particularly for microtubular SOCs. In this research, (La0.3Sr0.7)0.9Ti0.9Ni0.1O3-δ-Sm0.2Ce0.8O1.9 (LSTN-SDC) electrode-supported microtubular cell LSTN-SDC/YSZ/(La0.8Sr0.2)0.95MnO3-δ is fabricated and characterized. The LSTN-SDC microtubular substrate is prepared using an in-house built spinneret extrusion system in combination with modified phase inversion method, featuring radially well-aligned microchannels open at the inner surface. A thin YSZ electrolyte of ~15 μm and (La0.8Sr0.2)0.95MnO3-δ electrode of ~25 μm are then fabricated on the substrate, respectively. Upon reducing treatment, nickel is exsolved from LSTN grains and uniformly decorated onto grain surface as Ni nanoparticles, and therefore on inner surface of microchannels in the substrate. With CO/CO2 gas mixture as the fuel, the complicated electro-/chemical reactions are identified in the substrate electrode. The electrolysis process in combination with surface catalytic process of nanostructured electrode substrate leads to highly efficient CO production from CO2 with conversion efficiencies of well above 100%. The electrolysis also facilitates to regenerate surface catalytic functionality of nanostructured electrode substrate. The redox stability advantages of the cell are demonstrated in both alternative reduction (CO)/oxidation (air) atmospheric conditions and reversible operating mode.

Fabrication and characterization of microtubular solid oxide cell supported with nanostructured mixed conducting perovskite fuel electrode

Mixed ionic and electronic conducting (MIEC) perovskites demonstrate advantages over Ni-cermet as fuel electrode materials for solid oxide cells (SOCs). However, SOCs are primarily electrolyte-supported planar designs in literature when MIEC perovskite fuel electrodes are employed, which are relatively easy to fabricate but usually have high electrolyte ohmic resistance. Perovskite fuel electrode-supported designs are rarely studied particularly for microtubular SOCs. In this research, (La0.3Sr0.7)0.9Ti0.9Ni0.1O3-δ-Sm0.2Ce0.8O1.9 (LSTN-SDC) electrode-supported microtubular cell LSTN-SDC/YSZ/(La0.8Sr0.2)0.95MnO3-δ is fabricated and characterized. The LSTN-SDC microtubular substrate is prepared using an in-house built spinneret extrusion system in combination with modified phase inversion method, featuring radially well-aligned microchannels open at the inner surface. A thin YSZ electrolyte of ~15 μm and (La0.8Sr0.2)0.95MnO3-δ electrode of ~25 μm are then fabricated on the substrate, respectively. Upon reducing treatment, nickel is exsolved from LSTN grains and uniformly decorated onto grain surface as Ni nanoparticles, and therefore on inner surface of microchannels in the substrate. With CO/CO2 gas mixture as the fuel, the complicated electro-/chemical reactions are identified in the substrate electrode. The electrolysis process in combination with surface catalytic process of nanostructured electrode substrate leads to highly efficient CO production from CO2 with conversion efficiencies of well above 100%. The electrolysis also facilitates to regenerate surface catalytic functionality of nanostructured electrode substrate. The redox stability advantages of the cell are demonstrated in both alternative reduction (CO)/oxidation (air) atmospheric conditions and reversible operating mode.

Synthesis of Fe-Ag/f-MWCNT/PES nanostructured-hybrid membranes for removal of Cr(VI) from water

Abstract This work describes the synthesis of Fe-Ag/functionalized-multiwalled carbon nanotube (f-MWCNT)/polyethersulphone (PES) nanostructured-hybrid membranes via a modified phase inversion method and its permeability properties. As-synthesized MWCNTs were first treated with acid and then Fe and Ag nanoparticles (Fe-Ag NPs) were uniformly dispersed on the surface of the f-MWCNTs using a microwave-assisted polyol method prior to addition to the PES polymer matrix. The addition of Fe-Ag/f-MWCNTs into the PES polymer increased the surface roughness of PES membranes and resulted to a higher hydrophilicity. Thermal stability and crystallinity properties of PES were significantly improved. The Fe-Ag/f-MWCNTs enhanced the surface charge density of the PES membranes and were found not to leach from PES. Performance evaluation studies revealed that the addition of Fe-Ag/f-MWCNTs into the PES polymer matrix increased water flux from 26.5 to 36.9 L/m 2 h and improved the rejection of Cr 6+ ions (up to 94%) in a cross-flow system. Furthermore, the addition of Fe-Ag/f-MWCNTs improved fouling resistance of PES membranes. The improved properties of these hybrid membranes make the ideal for use as either point-of-use or end-of-use water purification system for production of potable water.