Tubular Substrates Research Articles

Increased Porosity in NiO-YSZ Tubular Substrate for High Performance Solid Oxide Electrolysis Cell Using LaGaO3 Film

Abstract Solid oxide electrolysis cells (SOECs) are an important subject for storage of renewable energy such as solar or wind power. In this study, tubular type SOECs using La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) electrolyte film were prepared on NiO-Y2O3 stabilized ZrO2 (YSZ) with different porosity and it was found that the porosity of the Ni-YSZ tubular substrate is an important parameter for achieving initial high current density and also low rate of durability by preventing the pulse potential noise. The addition of cornstarch as pore-formers was effective for increasing channel size (3.9 m of average radius) in Ni-YSZ substrate and when 15 wt% cornstarch was added for extruding NiO-YSZ substrate, the tubular cell exhibited the superior initial performance, 0.69 A cm-2 at 1.6 V in SOEC mode at 873K. This cell also shows smaller degradation rate by suppression of the pulse potential noise and the high coulomb efficiency of H2 formation. Increase in porosity of Ni-YSZ substrate is highly important for increasing the initial performance and long-term stability of SOEC.

Metal-organic framework membranes with scale-like structure for efficient propylene/propane separation

The fabrication of metal-organic framework (MOF) membranes with high propylene/propane selectivity, high mechanical endurance and ease of scaling up always remains a challenge. Inspired by the ubiquitous biological wear-resistant structure, here we show ZIF-67 membranes with a tangential-normal interlaced structure (TN-ZIF-67) for one-step acquisition of polymer-grade propylene, which is endowed with the merits of intergranular defect elimination, partial ZIF-67 lattice flexibility restriction and anti-wear of the membrane surface. The TN-ZIF-67 membrane exhibits an optimal propylene/propane mixture separation factor of 221, and the separation performance remained unchanged after 1.5 years of storage or abrasion by repeated sanding. The distinctive membrane structure can be further scaled up on 4 mm-diameter tubular substrates. This work demonstrates a strategy to extend the rational design of defect-free, anti-wear MOF membranes with superior separation performance and stability that could fulfill future industrial applications.

(High Temperature Materials Division Outstanding Achievement Award) Development of Novel Ion Conducting Materials for Use as Electrolytes and Electrodes in Intermediate Temperature Solid Oxide Cells

Oxide ion conductor is an important functional material in energy conversion and sensing area. In this presentation, development of new oxide ion conducting materials and their application in high temperature electrochemical cells such as the intermediate temperature solid oxide fuel cells (it-SOFCs) as well as electrolysis cell will be presented. In particular, in 1994, the high oxide ion conductivity in the perovskite structured material La1-xSrxGa1-yMgyO3 (LSGM) was fist time found in our group. LSGM is the first case of a pure oxide ion conducting perovskite oxide and now considered as a viable alternative to Y2O3 stabilized ZrO2 as an electrolyte for the intermediate temperature-SOFC. Not only high ion conductivity but also making thin film are important for achieving the superior electrochemical performance of solid oxide cells. In order to obtain a thin film of LSGM, several processing methods including pulsed laser deposition and conventional wet processing were tried. This resulted in an SOFC with an extremely high power density (3.3W/cm2 at 973K) opening the possibility of intermediate temperature operation at 873K. In addition, a solid oxide cell using an LSGM thin film electrolyte can be used for intermediate temperature (ca.873K) electrolysis and that a reasonable current density (>1A/cm2 at 1.6V) can be achieved at 873K. Preparation of microtubular cell using LSGM film with slurry coat method. In addition to the development of new oxide ion conducting electrolyte materials, highly active cathode and anode materials are also critical for the development of high performance it-SOFCs. In this talk, the development of new electrode materials was also introduced. Examples of the new cathode materials, the perovskite related oxides Pr2NiO4 and Ba(La)CoO3 and, for the anode, Ni-Fe based alloys will be introduced. The surface chemistry of these materials was also analyzed by using the advanced ion beam techniques, i.e., Secondary Ion Mass Spectroscopy (SIMS) and Low Energy Ion Scattering (LEIS). These unique studies showed that three dimensional tensile lattice strain can be successfully introduced by a dispersion of nano size metal particles, mainly, Au, onto the grains of ceramic Pr2NiO4. The resulting tensile strain induces increased oxygen diffusivity and surface activity to oxygen dissociation, providing a new paradigm for the design of the oxygen electrode for solid oxide cells. Using this knowledge, SOFCs with several different designs such as planar, tubular, and metal support cells, which always exhibited the high power densities suitable for commercialization. In particular, cycle stability of SOFC/SOEC was much increased on LSGM/Ni-YSZ tubular cells by infiltration of CeO2 nanoparticles. Figure 1 shows I-V curves of CeO2 infiltrated Ni-YSZ substrate in SOFC mode using LSGM film. It was found that the infiltration of higher concentration of Ce solution increased the maximum power density, because both IR loss and overpotential were significantly decreased. The maximum power density of the cell was 0.95 and 0.42 W cm-2 at 873 and 773 K, respectively at 3 M Ce nitrate infiltrated. The long-term stability of the cell was also measured by using the cell infiltrated with 1.5 M Ce, the stable power generation performance was demonstrated. The steam electrolysis performance of the cell using Ce infiltration was further studied and it was found that Ce also contributes to higher current density in SOEC operation and 1.07 A cm-2 at 1.6 V was achieved at 873 K using 2 M Ce infiltration. In this talk, development of solid oxide cells using LSGM will be introduced from materials to application.Figure 1 I-V, I-P curves of the SOFC cell using LSGM film deposited on Ce infiltrated Ni-YSZ tubular substrate. Figure 1

Nanocrystalline Lanthanum Oxide Layers on Tubes Synthesized Using the Metalorganic Chemical Vapor Deposition Technique.

Lanthanum oxide (La2O3) layers are widely used in electronics, optics, and optoelectronics due to their properties. Lanthanum oxide is also used as a dopant, modifying and improving the properties of other materials in the form of layers, as well as having a large volume. In this work, lanthanum oxide layers were obtained using MOCVD (Metalorganic Chemical Vapor Deposition) on the inner walls of tubular substrates at 600-750 °C. The basic reactant was La(tmhd)3 (tris(2,2,6,6-tetramethyl-3,5-heptanedionato)lanthanum(III)). The evaporation temperature of La(tmhd)3 amounted to 170-200 °C. Pure argon (99.9999%) and air were used as the carrier gases. The air was also intended to remove the carbon from the synthesized layers. Tubes of quartz glass were used as the substrates. La2O3 layers were found to be growing on their inner surfaces. The value of the extended Grx/Rex2 criterion, where Gr-Grashof's number, Re-Reynolds' number, x-the distance from the gas inflow point, was below 0.01. The microstructure of the deposited layers of lanthanum oxide was investigated using an electron scanning microscope (SEM). Their chemical composition was analyzed via energy-dispersive X-ray (EDS) analysis. Their phase composition was tested via X-ray diffraction. The transmittance of the layers of lanthanum oxide was determined with the use of UV-Vis spectroscopy. The obtained layers of lanthanum oxide were characterized by a nanocrystalline microstructure and stable cubic structure. They also exhibited good transparency in both ultraviolet (UV) and visible (Vis) light.

Zirconia encrusted ceramic composite membrane for uremic toxins removal: Fabrication and assessment of biocompatibility

In this study, tubular zirconia composite membranes (ZM1-ZM3) were developed using low-cost tubular substrate which was prepared utilizing naturally available clay materials by an extrusion approach. The zirconia nanoparticles were encrusted on a low-cost tubular substrate using spray pyrolysis technique. The membranes were investigated for their biocompatibility in addition to pore size, chemical stability, water permeability, porosity, contact angle, thermogravimetric (TGA), and X-ray diffraction (XRD). Water permeability, pore size and porosity of optimized membrane (ZM3) were 3.05 × 10–4 ± 0.03 L.m-2.h-1.Pa-1, 119 ± 0.57 nm and 36 ± 0.12 %, respectively. Platelets adhesion and protein adsorption were measured to be 4630 ± 46 platelets.mm-2, and 1.05 ± 0.02 μg.cm-2 respectively, while the activated partial thromboplastin time (APTT) and prothrombin time (PT) were 80 ± 0.51 s and 27 ± 0.26 s, respectively. Complement activation C3 and C4 concentrations were assessed to be 76.2 ± 0.88 mg.dL-1 and 21.57 ± 0.80 mg.dL-1, respectively and hemolysis ratio was 0.31 ± 0.01 %. Moreover, the membrane had a considerable antifouling nature with a flux recovery ratio of 89.22 ± 0.58 %. Protein retention was found to be 81.14 ± 0.58 %, in addition to outstanding sieving coefficients of uremic toxins like urea (0.95 ± 0.005), creatinine (0.93 ± 0.004), and phosphate (0.90 ± 0.004). These findings suggest that the produced tubular zirconia composite membrane has the potency for hemofiltration.

Narrowband-UVB-emitting gadolinium-doped yttrium oxide nanofilm on xenon excimer lamp for phototherapy

The continuous utilization of ultraviolet (UV) light sources within both academic and industrial contexts necessitates the imperative advancement of alternative UV sources to replace hazardous mercury lamps. Herein, we proposed a mercury-free narrowband UVB (NB-UVB)-emitting device from Y2O3:Gd3+ nanofilm on a tubular quartz substrate. The nanofilm is fabricated utilizing the spin-coating sol-gel precursor technique and is subsequently synthesized via a high-annealing temperature solid-state reaction. This synthesis resulted in the formation of a single-phase cubical structure of Y2O3 characterized by a crack-free morphology. The NB-UVB radiative output with a peak at 315 nm is generated through vacuum UV-induced photoluminescence originating from the emission of Xe excimer, which subsequently excites the Gd3+ luminescent centers incorporated within the Y2O3 host matrix. Moreover, in a high-voltage bipolar power system operating at 19 kV and 19 kHz, the device exhibited an NB-UVB radiance output of 1.34 mW, accompanied by a power efficiency of 0.02 %, whilst preserving exceptional temporal performance. Thus, this investigation introduces an innovative perspective on a mercury-free NB-UVB-emitting device, thereby promoting further exploration into the application of UV radiation sources derived from excimer lamp technology.

Multiscale nanoengineering fabrication of air electrode catalysts in rechargeable Zn-air batteries

The development of cost-effective, high-activity and stable catalysts to accelerate the sluggish kinetics of cathodic oxygen reduction/evolution reactions (ORR/OER) plays a critical part in commercialization application of rechargeable Zn-air batteries (RZABs). Herein, a multiscale nanoengineering strategy is developed to simultaneously stabilize Co-doped Fe nanoparticles originated from metal-organic framework-derived approach and atomic Fe/Co sites derived from metal nanoparticle-atomized way on N-doped hierarchically tubular porous carbon substrate. Thereinto, metal nanoparticles and single atoms are respectively used to expedite the OER and ORR. Consequently, the final material is acted as an oxygen electrode catalyst, displaying 0.684 V of OER/ORR potential gap, 260 mW cm-2 of peak power density for liquid-state RZAB, 110 mW cm-2 of peak power density for solid-state RZAB, and 1000 charge-discharge cycles without decay, which confirms great potential for energy storage and conversion applications.

Optimization of Deposition Parameters of SnO2 Particles on Tubular Alumina Substrate for H2 Gas Sensing

Resistive gas sensors, which are widely used for the detection of various toxic gases and vapors, can be fabricated in planar and tubular configurations by the deposition of a semiconducting sensing layer over an insulating substrate. However, their deposition parameters are not often optimized to obtain the highest sensing results. Here, we have investigated the effect of deposition variables on the H2 gas sensing performance of commercially available SnO2 particles on tubular alumina substrate. Utilizing a tubular alumina substrate equipped with gold electrodes, we varied the number of deposited layers, rotational speed of the substrate, and number of rotations of the substrate on the output of the deposited sensor in terms of response to H2 gas. Additionally, the effect of annealing temperatures (400, 500, 600, and 700 °C for 1 h) was investigated. According to our findings, the optimal conditions for sensor fabrication to achieve the best performance were the application of one layer of the sensing material on the sensor with ten rotations and a rotation speed of 7 rpm. In addition, annealing at a lower temperature (400 °C) resulted in better sensor performance. The optimized sensor displayed a high response of ~12 to 500 ppm at 300 °C. This study demonstrates the importance of optimization of deposition parameters on tubular substrates to achieve the best gas sensing performance, which should be considered when preparing gas sensors.

Controlled Pore Size of NiO-YSZ Tubular Substrate for Improved Performance of Reversible Solid Oxide Cell Using LaGaO3 Electrolyte Film

Effects of channel size in NiO-YSZ porous substrate were studied on power density in solid oxide fuel cell mode and electrolysis current in steam electrolysis mode. It was found that the cell deposited on anode substrate with larger pore diameter shows a superior performance. The LSGM cell prepared on Ni-YSZ tube with average channel diameter of ca. 2.5 μm shows the maximum power density of 0.36 W cm−2 in SOFC mode and 0.42 A cm−2 at 1.6 V in SOEC mode at 873 K. Spike potential noise which may be caused by insufficient gas diffusion in NiO-YSZ porous substrate was observed under constant current electrolysis condition in case of NiO-YSZ tube with narrow channel and the spike noise is suppressed by increasing channel size. NiO-YSZ tube with large channel size is also effective for increasing long term stability in electrolysis mode.

On-demand switchable superamphiphilic nanofiber membrane reinforced by PET braided tube for efficient wastewater purification and photocatalytic regeneration

Nanofiber membrane is regarded as one of the ideal candidates for complex wastewater purification. However, the membrane fragility, fouling and dull wettability limits its widespread application. In this work, a hybrid zeolitic imidazolate framework-8 @zinc oxide nanorod decorated poly (vinylidene fluoride) tubular nanofiber membrane (ZIF-8 @ZnO/PVDF-TNM) was developed based on a polyester braided tubular reinforcement substrate. The hybrid membrane was fabricated by ZnO seeds conversion, ZnO nanowire growth via hydrothermal technique and ZIF-8 deposition using self-template scarifying method. The resultant ZIF-8 @ZnO/PVDF-TNM possesses enhanced photocatalytic capacity for pollutants removal and superamphiphilicity or under-liquid superamphiphobicity depending on its nanoarchitecture. In virtue of well-grown ZIF-8 @ZnO nanorods, the membrane exhibits a commendable permeation ability (784 and 865 L·m−2·h−1 for water and oil, respectively) under gravity operation, superior oil/water separation efficiency (> 99.9%) for various emulsions. Moreover, it can achieve high-efficient pollutants degradation, self-cleaning and membrane regeneration by solar light irradiation. This study demonstrates a new approach to fabricate the switchable superamphiphilic nanofiber membrane for water remediation and membrane regeneration.

Investigating the efficiency of a ceramic-based thin-film composite nanofiltration membrane for dyes removal

This study focuses on producing polyamide thin-film composite (TFC) ceramic membranes using interfacial polymerization, resulting in a polyamide layer on ceramic tubular substrates (Al2O3). These Al2O3 substrates possess robust mechanical and physical traits, featuring a porous surface structure. TFC membranes exhibit a thin, dense structure with root-like nanostructures on the ceramic base, with a thickness of around 260 nm. Atomic force microscopy confirms the smoother surface of TFC membranes with an average roughness value of 18 nm compared to ceramic tubular substrates. TFC membranes exhibit negative zeta potentials within a pH range of 4.7–10, while ceramic tubular substrates show more complex zeta potential behavior. Both substrate and TFC membranes are hydrophilic, with the TFC membrane having a slightly higher water contact angle (approximately 43 ± 1°). Zeta potential analysis reveals a negative potential of around −23 mV for the TFC membrane. In water permeability tests, the ceramic tubular substrate membrane demonstrates high permeability, whereas the TFC membrane displays slightly lower permeability (28 ± 0.8 L/m2 h bar) due to the presence of the polyamide selective layer. Importantly, the TFC membrane significantly enhances organic dye rejection compared to the ceramic tubular substrate, with rejection rates of 95% for CR, 92% for BTB, and 86% for MB. Rejection performance is mainly influenced by size exclusion and dye molecular charge. These novel TFC ceramic nanofiltration membranes offer improved water permeability while maintaining selectivity, holding promise for effectively removing organic pollutants in water treatment applications.

Micro Tubular Solid Oxide Reversible Cell Using LaGaO3 Electrolyte Film Prepared on Channel Size Controlled NiO-YSZ Substrate

Reversible operation of SOFC is now important subjects from energy storage of renewable electric power from solar or wind power. At present, planer type cell design is widely used for this purpose, however, because of tight gas sealing, tubular type cell design is more suitable. In this study, micro tubular solid oxide cell using La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) thin electrolyte film was prepared by dip-coating and co-sintering process.NiO-YSZ porous substrate with 10 mm diameter and 30 mm length was used for preparation of the cell. LaGaO3 based oxide film was deposited with dip coating method. Two kinds of NiO and YSZ particles with different particle size (0.91 and 0.65 mm for NiO and 0.62 and 0.25 mm for YSZ) were mixed and extruded for tubular substrate. 4 types of NiO-YSZ anode porous substrate were Average porosity of each 4 tubular substrate was ca. 70% after reduction. However, from SEM observation, channel size in NiO-YSZ substrate was changed and NiO-YSZ using larger NiO and YSZ particles shows larger channel diameter.Power generation property of 4 tubular cell using different NiO and YSZ particle size for substrate. It was found that the cell deposited on NiO-YSZ using larger particles shows lager power density, in particular, the cell using both NiO and YSZ larger particles shows the largest power density (0.37 W/cm2 at 873 K), which is reasonably large power density. On the other hand, in case of electrolysis, channel size is also strongly influenced on the electrolysis current. As similar manner with fuel cell operation, the LSGM cell prepared on larger particles size of NiO and YSZ shows larger steam electrolysis current. Impedance analysis suggests that the effects of particle size of NiO and YSZ was explained by small concentration overpotential, and so larger channel size is effective for improving the initial performance of the SORC performance. Long term stability of the steam electrolysis was performed and it was found that the LSGM tubular cell prepared on NiO-YSZ with larger particles shows the reasonable stable electrolysis performance in long term stability (-4%/1000h average degradation rate). The main reason for degradation was assigned to the increased IR loss however overpotential was hardly changed over 600 h and so it seems most likely that the reoxidation of NiO or aggregation of NiO is the main reason for degradation of the cell.This study reveals that the control of channel size in NiO-YSZ porous substrate is highly important for initial performance and long-term stability of SORC.

Synthesis of an IMF zeolite membrane for the separation of xylene isomer

The synthesis of a continuous IMF zeolite membrane was fabricated on tubular substrates by seeded growth for the first time. The straight channels of IMF zeolite with diameters of 0.53–0.59 nm are distinguishable for p-xylene from o-xylene molecules. Pure IMF-phase high-silica IM-5 zeolite seeds with uniform and fine crystal size were fabricated by a new sonication-assisted aging process. The seeds were coated on the support by dipcoating and induced the formation of continuous membrane. Separation performance in p-/o-xylene mixture was investigated at various temperature and pressure. The typical IM-5 zeolite membrane had p-/o-xylene separation factor of 3.7. Our results suggest that IM-5 zeolite is a potentially good membrane material for the separation of xylene mixtures.

ZnO/CuO nanostructures anchored over Ni/Cu tubular films via pulse electrodeposition for photocatalytic and antibacterial applications

In this work, we report the fabrication of Ni and Cu tubular substrates and the synthesis of ZnO/CuO nanocomposite on them through the process of pulse electrodeposition. The systematic variation in CuO incorporation in the ZnO matrix and the processing technique were noticed to affect the structural, optical, photocatalytic, and anti-bacterial properties, which are well in accordance with the Field Emission-Scanning Electron Microscope, X-ray Diffraction, Fourier transform Infrared Spectroscopy and UV-Differential reflectance spectroscopy results. The remediation capabilities of the photocatalytic substrates were assessed through the degradation of methylene blue (MB) dye under solar irradiation. Optimized CuO incorporation within the ZnO nanorods resulted in the degradation of a 20 ppm of MB dye solution within 40 min and a higher concentration of 50 ppm within 95 min. The Ni and Cu electroformed tubes as substrates provided not only a reusable supporting frame but also a large surface-area for the growth of ZnO/CuO nanocomposite. The current study also dealt with the anti-bacterial efficacy of the above-mentioned substrates against E.coli. Hence, the Ni and Cu tubular thin film substrates with nanorods of ZnO/CuO composite were explored for the removal of organic as well as biological contaminants from waste water.

Single Vs Multichannel Silica-Pectin Ultrafiltration Membranes for Treatment of Natural Peat Water

A comparative study was undertaken to investigate the potential of silica-pectin ultrafiltration membrane on varied operation pressure (0.1-0.3 MPa). Cross-flow ultrafiltration works were explored with tubular alumina substrates in single and multichannel configuration. The silica-pectin sol was prepared from TEOS as silica precursor by sol-gel method, afterward pectin was templated into the silica sol to induce carbon on it. Thereafter, both of single and multichannel alumina substrates was coated by the silica-pectin sol via inner coating technique. The study exhibited better performance of multichannel silica-pectin ultrafiltration membrane (with 4 bores) compared to the single channel membrane in terms of the permeate quality of UV254 rejection, as well as the permeate flux. The UV254 rejection of multichannel silica-pectin ultrafiltration membranes conducted over 84% in compliance with highest permeate fluxes of 234.3 L.m-2.h-1.bar-1 at high operation pressure (TMP 0.3 MPa). The multichannel ultrafiltration membrane permeate flux in this work is slightly high 60-75% over single channel. Hence, both single and multichannel silica-pectin membranes exhibited steady neutralized permeate fluxes under TMP 0.3 MPa conditions for natural 100% peat water concentration, which indicates that fouling is not occurred during filtration time up to 60 min. Therefore, multichannel silica-pectin ultrafiltration membrane in this work is success to treatment of natural peat water, that the natural organic matter removal was found to be fit for uses as clean water sources.

Polyamide nanofiltration membrane with MoS2 interlayer on tubular ceramic substrate for desalination

The tubular ceramic substrate has great potential in membrane separation because of its excellent solvent and temperature resistance, pressure stability, and long service life. However, it is still a challenge to prepare an ultrathin intact selective layer by interfacial polymerization (IP) on a porous tubular ceramic substrate, due to its large pore size and defects on the surface. In this study, a molybdenum sulfide (MoS2) interlayer with a loose structure was formed on the tubular ceramic substrate via hydrothermal, which provided a large surface area and fast transport channels. Subsequently, a polyamide (PA) skin layer was formed on the MoS2 interlayer through the IP procedure to obtain a composite membrane for desalination. The prepared PA/MoS2/ceramic composite membrane showed excellent water permeance of 17.7 L·m−2·h−1·bar−1 with a 96.8 % rejection of Na2SO4. Moreover, the prepared membranes showed good pressure resistance and long-term stability under cross-flow filtration within 30 days.

Fast‐current‐driven synthesis of ultrathin ZIF‐8 membrane on ceramic tube for propene/propane separation

AbstractMOF membranes are very promising in molecular separation, but it is still a challenge for industrial applications due to the complex and time‐consuming synthesis. We use the fast current‐driven synthesis (FCDS) method to achieve controlled growth of ZIF‐8 membranes on porous graphite‐coated ceramic tubes by controlling the growth time and current density. Grown for 30 min at a current density of 0.74 mA/cm2, the ZIF‐8 membrane exhibits selectivity for C3H6/C3H8 up to 63 with C3H6 permeance of 6 × 10−9 mol/(m2 s Pa). Furthermore, the ZIF‐8 membrane exhibits a pressure resistance of up to 3 bar and good stability of ~96 h. This work realizes the breakthrough of the MOF membrane synthesis via FCDS method from the frequently‐used expensive and fragile anodic aluminum oxide (AAO) disc substrate to the tough ceramic tubular substrate, which broadens the road for the industrialization of MOF membranes in gas separation fields.

Fabrication of robust ceramic supported polymeric composite nanofiltration membrane for heavy metal contaminated wastewater treatment

Nanofiltration (NF) membranes with positive charge are essential for efficient removal of heavy metals and salts from waste water. In this work surface modified positively charged novel ‘ceramic-supported-polymeric’ (CSP) composite NF membranes were fabricated with the copper ions embedded crosslinked polyethyleneimine polymer matrix over tubular ceramic substrate using facile dipcoating method. EDX, ATR-FTIR, XPS, FESEM, AFM and contact angle analyses were performed to characterize the chemical structures and morphologies of the prepared membranes. The composite NF membrane exhibited satisfactory pure water permeability (PWP) of 8.1 L.m−2.h−1.bar−1 and promising salt (87.19 % and 74.41 % for Mg2+ and Ca2+, respectively) and heavy metal ion rejections (91.73 %, 83.15 % and 75.50 % for Zn2+, Ni2+ and Cd2+, respectively). Activation energy and overall size-exclusion-dehydration phenomena along with steric hindrance and Donnan electrostatic exclusion plays an important role for heavy metals and salts rejection. In addition, the membrane showed excellent antifouling properties (>99 % humic acid removal) with high flux recovery ratio (77.6 %) and low flux decline ratio (33 %) for 5 h operations (3rd cycle) together with outstanding antibiofouling ability towards Brevibacillusagri and Leclerciaadecarboxylata. Furthermore, excellent chemical stability of the membrane suggests its potential application for waste water treatment under critical conditions.

Infiltrated nano-CeO2 and inserted Ni-Fe active layer in a tubular cathode substrate for high temperature CO2 electrolysis on solid oxide cells using La0.9Sr0.1Ga0.8Mg0.2O3−δ thin film electrolyte

A tubular type solid oxide cell which consists of a NiO-Y 2 O 3 stabilized ZrO 2 (YSZ) tubular cathode substrate, a La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ (LSGM) electrolyte film and a Sm 0.5 Sr 0.5 CoO 3-δ (SSC) anode was prepared by dip-coating for CO 2 electrolysis at 800 °C. Since Ni in Ni-YSZ substrate is easily re-oxidized under a pure CO 2 electrolysis atmosphere, co-feeding a reductive gas was essential for avoiding Ni re-oxidation and achieving a stable and large CO 2 electrolysis current under high temperature operation. It was found that co-feeding H 2 is more effective for preventing re-oxidation of Ni compared with CO, however, the CO formation rate was slightly lower than that estimated amount by Faraday`s law due to a water shift reaction when H 2 was used as a reductive gas. Deposition of a thin Ni-Fe cathode active layer and CeO 2 nano-particles obtained by infiltration were effective for increasing the CO 2 electrolysis current because of the decrease in the cathodic overpotential. In spite of the low concentration of Ce was infiltrated by using a 1 M solution with a dip process, the volume change in substrate caused by the CO 2 oxidant was also measured. The CO formation rate almost corresponded to the amount estimated by Faraday`s law and the coke deposition was hardly observed in Ni-YSZ substrate after CO 2 electrolysis, when 10% or 5% of CO was co-fed.

Alcohols assisted in-situ growth of MoS2 membrane on tubular ceramic substrate for nanofiltration

Molybdenum disulfide-based membranes have received wide attention for their excellent performance in chemical separation field. Yet, manipulating the structure of MoS2 membranes still remains an unprecedented challenge. In this work, the tubular MoS2 ceramic membranes were prepared by in-situ hydrothermal method using aqueous solution of thiourea and ammonium molybdate as precursor solution. The structure and morphology of the membranes were manipulated by introducing different alcohols into the precursor solution. The results indicated that the presence of alcohols drove the transformation of MoS2 morphology from nanosheets to spherical aggregates. As the molecular weight of the alcohols decreased, more small-sized molybdenum disulfide spheres were formed on the tubular ceramic substrate, which resulted in the formation of a great number of large transportation channels and promotion of surface area, and thereby improved the permeability of the membrane. Moreover, the addition of different alcohols enhanced the negative charge of the membrane surface, which ensured an effective rejection while enhancing the membrane permeability. The results demonstrate that the membranes prepared in a water-ethanol mixed solvent possess an excellent permeability for water (33.2 L/(m2 h bar)) and methanol (52.2 L/(m2 h bar)), with a rejection of more than 97% for Eriochrome black T, and an excellent pressure resistance as well as long-term running stability under cross-flow filtration. In addition, such membrane exhibited a below 30% rejection for salts, which can be utilized for dye desalination.