Publications
369 results found
Chi Y, Li T, Wang B, et al., 2017, Morphology, performance and stability of multi-bore capillary La0.6Sr0.4Co0.2Fe0.8O3-δ oxygen transport membranes, Journal of Membrane Science, Vol: 529, Pages: 224-233, ISSN: 0376-7388
Mixed ionic-electronic conducting 3, 4, 7-bore capillary membranes made of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) were successfully prepared by the combined phase inversion/sintering technique. The membranes fabricated have asymmetric wall structures with micro-channels formed in between surfaces, and dense layers sandwiched in between the micro-channels. By changing the solvent from DMSO to NMP, changes in the morphology of the 7-bore membrane were observed, where the separation layer has reduced its effective thickness. The multi-bore membranes exhibited 3-point bending fracture loads of 10.4, 13.5, 15.4 and 11.7 Newton with a 3 cm testing span for the 3-bore , 4-bore, 7-bore-DMSO and 7-bore-NMP samples, respectively, which are much stronger than single-bore hollow fibre membranes. Oxygen permeation of the multi-bore membranes was measured with a sweep gas flow through lumen and the effect of operating temperature has on the performance was studied between 750 °C to 1000 °C. Oxygen fluxes measured are comparable to typical sandwich-like structured single-bore hollow fibres at temperatures below 900 °C, but are notably higher at higher temperatures owe to their thinner membrane walls. The 200-hour long-term permeation test conducted on the 7-bore membrane showed a slight increase in permeation flux, but the sign of kinetic demixing/decomposition appeared on the outer surface, where the surface of the thinnest membrane walls underwent faster demixing/decomposition than the thickest walls. In summary, the results demonstrated that multi-bore configurations can achieve optimised material distribution during the fabrication, and can obtain strong mechanical property, high permeation flux for the final products whilst maintaining high membrane area to volume ratios.
Lu X, Tjaden B, Bertei A, et al., 2017, 3D characterization of diffusivities and its impact on mass flux and concentration overpotential in SOFC anodes, Journal of the Electrochemical Society, Vol: 164, Pages: F188-F195, ISSN: 0013-4651
In recent years great effort has been taken to understand the effect of gas transport on the performance of electrochemical devices. This study aims to characterize the diffusion regimes and the possible inaccuracies of the mass transport calculation in Solid Oxide Fuel Cell (SOFC) anodes when a volume-averaged pore diameter is used. 3D pore size distribution is measured based on the extracted pore phase from an X-ray CT scan, which is further used for the calculation of a Knudsen number (Kn) map in the porous medium, followed by the voxel-based distribution of the effective diffusion coefficients for different fuel gases. Diffusion fluxes in a binary gas mixture using the lower boundary, upper boundary and average effective coefficients are compared, and the impact on overpotential is analyzed. The results show that pore diameters from tens to hundreds of nanometers result in a broad range of Knudsen number (1.1 ∼ 4.8 and 0.6 ∼ 3 for H2 and CH4 respectively), indicative of the transitional diffusion regime. The results highlight that for a porous material, such as an SOFC anode where Knudsen effects are non-negligible, using a volume-averaged pore size can overestimate the mass flux by ±200% compared to the actual value. The characteristic pore size should be chosen sensibly in order to improve the reliability of the mass transport and electrochemical performance evaluation.
Lu X, Li T, Taiwo OO, et al., 2017, Study of the tortuosity factors at multi-scale for a novel-structured SOFC anode, 13th International X-Ray Microscopy Conference (XRM), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
Liu X, Wang C, Wang B, et al., 2016, Novel Organics-Dehydration Membranes Prepared from Zirconium Metal-Organic Frameworks, Advanced Functional Materials, Vol: 27, ISSN: 1616-3028
Membranes with outstanding performance that are applicable in harsh environments are needed to broaden the current range of organics dehydration applications using pervaporation. Here, well-intergrown UiO-66 metal-organic framework membranes fabricated on pre-structured yttria-stabilized zirconia hollow fibers is reported via controlled solvothermal synthesis. On the basis of adsorption-diffusion mechanism, the membranes provides a very high flux of up to ca. 6.0 kg m-2 h-1 and excellent separation factor (> 45000) for separating water from i-butanol (next-generation biofuel), furfural (promising biochemical) and tetrahydrofuran (typical organic). This performance, in terms of separation factor, is one to two orders of magnitude higher than that of commercially available polymeric and silica membranes with equivalent flux. It is comparable to the performance of commercial zeolite NaA membranes. Additionally, the membrane remains robust during a pervaporation stability test (~300 hours), including exposure to harsh environments (e.g., boiling benzene, boiling water and sulfuric acid) where some commercial membranes (e.g., zeolite NaA membranes) cannot survive.
Li T, Rabuni MF, Kleiminger L, et al., 2016, Highly-robust solid oxide fuel cell (SOFC): simultaneous greenhouse gas treatment and clean energy generation, RSC Energy and Environment Series, Vol: 9, Pages: 3682-3686, ISSN: 2044-0774
Herein, results of combined greenhouse gas treatment with clean energy conversion is reported for the first time. Multi-channel tubular SOFCs were operated with N2O instead of air as the oxidant leading to a 50% increase in power density. Techno-economic evaluation suggested the feasibility of the combined approach eliminating the cost penalty for N2O abatement.
lee M, wang B, Li K, 2016, High-capacity open bore membrane chromatography column based on micro-packed ceramic hollow fibres, Journal of Membrane Science, Vol: 524, Pages: 73-78, ISSN: 1873-3123
Micro-structured ceramic hollow fibres as a new (GC) column configuration has been designed, fabricated, and executed for the separation of gases. The design consists of ceramic hollow fibres with intensively self-arranged open micro-channels in its wall as storage space, and the stationary phase is packed inside the micro-channels. The hollow lumen leads to negligible pressure drop along the GC column that is similar to the common capillary columns, whilst the intensively distributed micro-channels provide spacious volume for packing the stationary phase to realise much enhanced capacity that is close to common packed columns. Using alumina hollow fibre as an example, this novel design has been demonstrated as a GC column packed with 5Å molecular sieve particles and used to successfully separate nitrogen and oxygen. Such a GC column with a length of 8 m was able to separate O2 and N2 completely, with an injection volume of 90 μL, which is 20 -30 times higher than a typical capillary column, and a negligible pressure drop of only 0.01 bar. The theoretical plate number of this column for oxygen is up to almost 30 times higher than a commercial packed column’s, and for nitrogen it is almost 10 times higher.
Wang B, Ji J, Li K, 2016, Crystal nuclei templated nanostructured membranes prepared by solvent crystallization and polymer migration, Nature Communications, Vol: 7, Pages: 1-8, ISSN: 2041-1723
Currently, production of porous polymeric membranes for filtration is predominated by the phase-separation process. However, this method has reached its technological limit, and there have been no significant breakthrough over the last decade. Here we show, using polyvinylidene fluoride as a sample polymer, a new concept of membrane manufacturing by combining oriented green solvent crystallization and polymer migration is able to obtain high performance membranes with pure water permeation flux substantially higher than those with similar pore size prepared by conventional phase-separation processes. The new manufacturing procedure is governed by fewer operating parameters and is, thus, easier to control with reproducible results. Apart from the high water permeation flux, the prepared membranes also show excellent stable flux after fouling and superior mechanical properties of high pressure load and better abrasion resistance. These findings demonstrate the promise of a new concept for green manufacturing nanostructured polymeric membranes with high performances.
Othman NH, Shahruddin MZ, Sihar AS, et al., 2016, In-Situ Catalytic Surface Modification of Micro-Structured La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) Oxygen Permeable Membrane Using Vacuum-Assisted technique, 5th International Conference on Chemical and Process Engineering (ICCPE 2016), Publisher: EDP Sciences, Pages: 05002-05002, ISSN: 2261-236X
This paper aims at investigating the means to carry out in-situ surface modification of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) oxygen permeable membrane by using vacuum assisted technique. The unique structure of the LSCF hollow fibre membrane used in this study, which consists of an outer dense oxygen separation layer and conical-shaped microchannels open at the inner surface has allowed the membrane to be used as oxygen separation membrane and as a structured substrate for where catalyst can be deposited. A catalyst solution of similar material, LSCF was prepared using sol-gel technique. Effects of calcination temperature and heating rate were investigated using XRD and TGA to ensure pure perovskites structure of LSCF was obtained. It was found that a lower calcination temperature can be used to obtain pure perovskite phase if slower heating rate is used. The SEM photograph shows that the distribution of catalyst onto the membrane microchannels using in-situ deposition technique was strongly related to the viscosity of LSCF catalytic sol. Interestingly, it was found that the amount of catalyst deposited using viscous solution was slightly higher than the less viscous sol. This might be due to the difficulty of catalyst sol to infiltrate the membrane and as a result, thicker catalyst layer was observed at the lumen rather than onto the conical-shaped microchannels. Therefore, the viscosity of catalyst solution and calcination process should be precisely controlled to ensure homogeneous catalyst layer deposition. Analysis of the elemental composition will be studied in the future using energy dispersive X-ray Spectroscopy (EDX) to determine the elements deposited onto the membranes. Once the elemental analysis is confirmed, oxygen permeation analysis will be carried out.
Wang CH, Lee M, Liu X, et al., 2016, A metal–organic framework/α-alumina composite with a novel geometry for enhanced adsorptive separation, Chemical Communications, Vol: 52, Pages: 8869-8872, ISSN: 1364-548X
The development of a metal–organic framework/α-alumina composite leads to a novel concept: efficient adsorption occurs within a plurality of radial micro-channels with no loss of the active adsorbents during the process. This composite can effectively remediate arsenic contaminated water producing potable water recovery, whereas the conventional fixed bed requires eight times the amount of active adsorbents to achieve a similar performance.
Li K, Wang C, Liu XL, et al., 2016, Applications of Water Stable Metal-Organic Frameworks, Chemical Society Reviews, Vol: 45, Pages: 5107-5134, ISSN: 1460-4744
The recent advancement of water stable metal–organic frameworks (MOFs) expands the application of this unique porous material. This review article aims at studying their applications in terms of five major areas: adsorption, membrane separation, sensing, catalysis, and proton conduction. These applications are either conducted in a water-containing environment or directly targeted on water treatment processes. The representative and significant studies in each area were comprehensively reviewed and discussed for perspectives, to serve as a reference for researchers working in related areas. At the end, a summary and future outlook on the applications of water stable MOFs are suggested as concluding remarks.
Mautner A, Maples HA, Kobkeatthawin T, et al., 2016, Phosphorylated nanocellulose papers for copper adsorption from aqueous solutions, International Journal of Environmental Science and Technology, Vol: 13, Pages: 1861-1872, ISSN: 1735-2630
Copper is a major problem in industrial wastewater streams, seriously affecting the quality of potential drinking water. Several approaches, including continuous membrane processes or batch-wise application of adsorbents, are in use to tackle this problem. Unfortunately, these processes suffer from their particular drawbacks, such as low permeance or disposal of saturated adsorbents. However, a combination of these processes could constitute a step towards a more efficient copper removal solution. Here, we present a nanopaper ion-exchanger prepared from cellulose nanofibrils produced from fibre sludge, a paper industry waste stream, for the efficient, continuous removal of copper from aqueous solutions. This nanopaper ion-exchanger comprises phosphorylated cellulose nanofibrils that were processed into nanopapers by papermaking. The performance of these phosphorylated nanopaper membranes was determined with respect to their rejection of copper and permeance. It was shown that this new type of nanopaper is capable of rejecting copper ions during a filtration process by adsorption. Results suggest that functional groups on the surface of the nanopapers contribute to the adsorption of copper ions to a greater extent than phosphate groups within the bulk of the nanopaper. Moreover, we demonstrated that those nanopaper ion-exchangers could be regenerated and reused and that in the presence of calcium ions, the adsorption capacity for copper was only slightly reduced.
Ho WSW, Li K, 2016, Editorial overview: Separation engineering: Recent advances in separation science and technology, Current Opinion in Chemical Engineering, Vol: 12, Pages: vii-xi, ISSN: 2211-3398
Chong J, Wang B, Li K, 2016, Graphene oxide membranes in fluid separations, Current Opinion in Chemical Engineering, Vol: 12, Pages: 98-105, ISSN: 2211-3398
All rights reserved.Recently, considerable work has been performed to explore the potential of graphene-based materials for various membrane applications. Graphene oxide (GO) membranes have shown excellent performance in gas and liquid separations. The transport phenomena and microstructures of GO membranes are some interesting fundamentals in GO membranes. In this article, we highlight the milestones achieved by GO membranes and briefly discuss some fundamental understandings of the membranes in fluid separations. The challenges and prospects of GO membranes for scale-up applications will also be presented.
Ranieri G, Mazzei R, Wu Z, et al., 2016, Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor, Molecules, Vol: 21, ISSN: 1431-5157
Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%), which remains constant after 6 reaction cycles.
Mautner A, Li K, Bismarck A, 2016, Cellulose nanopapers as ion-exchangers for nitrate and heavy metal removal, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Mautner A, Maples HA, Sehaqui H, et al., 2016, Nitrate removal from water using a nanopaper ion-exchanger, Environmental Science: Water Research & Technology, Vol: 2, Pages: 117-124, ISSN: 2053-1400
Nitrates seriously affect drinking water quality. We herein present a process for the efficient removal of nitrates from water using a nanopaper ion-exchanger, which can be operated in flow-through conditions. The nanopaper ion-exchanger was produced from nanofibrillated cellulose obtained from fibre sludge, a paper-production waste stream, using a simple paper-making process. The cellulose nanofibrils were modified with quaternary trimethylammonium groups. The performance of these cationic nanopaper ion-exchangers was assessed with respect to their permeance and nitrate adsorption. Nitrates could be successfully captured onto the cationic nanopaper and thus rejected from contaminated water during dynamic filtration experiments. The ion-exchange nanopaper had adsorption capacities in the range of commercial available adsorbers but with the advantage of reduced contact time.
Othman NH, Shahruddin MZ, Sihar AS, et al., 2016, In-Situ Catalytic Surface Modification of Micro-Structured La<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.2</sub>Fe<sub>0.8</sub>O<sub>3-δ</sub> (LSCF) Oxygen Permeable Membrane Using Vacuum-Assisted technique, 5th International Conference on Chemical and Process Engineering (ICCPE), Publisher: E D P SCIENCES, ISSN: 2261-236X
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Wang B, Lee M, Li K, 2015, YSZ-Reinforced Alumina Multi-Channel Capillary Membranes for Micro-Filtration, Membranes, Vol: 6, ISSN: 2077-0375
The combined phase-inversion and sintering method not only produces ceramic hollow fibre membranes with much lower fabrication costs than conventional methods, but these membranes can also be designed to have greatly reduced transport resistances for filtration processes. The bottleneck of this technique is the weak mechanical property of the fibres, due to the small dimensions and the brittle nature of the ceramic materials. In this study, yttrium stabilised zirconia (YSZ) reinforced alumina seven-channel capillary microfiltration membranes were prepared with a pore size of ~230 nm and their mechanical property and permeation characteristics were studied. It is found that the addition of YSZ can effectively enhance the mechanical property of the membrane and also increase pure water permeation flux. The Al2O3-YSZ seven-channel capillary membranes could reach a fracture load of 23.4 N and a bending extension of 0.54 mm when being tested with a 6 cm span, to meet the requirements for most industrial microfiltration applications.
Lee M, Wang B, Li K, 2015, New designs of ceramic hollow fibres toward broadened applications, Journal of Membrane Science, Vol: 503, Pages: 48-58, ISSN: 1873-3123
Three structural designs for ceramic membranes have been achieved for the first time through the co-extrusion of polymeric and ceramic layers. During co-extrusion, micro-channels are initiated due to the Rayleigh–Taylor instability and they propagate through the different layers. The polymeric layer(s) is then calcined off during the heat treatment step, which opens the micro-channels and following sintering a ceramic membrane with open micro-channels ranging from a few to a few tens of micrometres in diameter can be formed. These long, straight and non-tortuous micro-channels can be controlled to be open at any or all of the surfaces. Design 1 has open micro-channels passing through the entire membrane wall, Design 2 has a separation layer at the lumen and open micro-channels at the shell side, and Design 3 has open micro-channels from both lumen and shell sides sandwiching a separation layer of sponge-like structure. Aside from having much improved mass transfer property due to the reduced effective membrane thickness, they can be easily incorporated into hybrid systems with anticipated improvements in unit compactness and performance. The pure water permeation of Design 2 reached up to 159,000 L/m2 h bar with pore sizes in the micro-filtration range. The micro-channels are easily accessible from the shell/lumen side; therefore catalysts or adsorbents can be easily deposited into the micro-channels. Examples of possible applications include a high-efficiency dispersing device realised with Design 1; a gas chromatography column for gas separation with very low pressure drop realised with Design 2 and a highly compact membrane micro-reactor for consecutive reactions proposed with Design 3.
Ji J, Zhou S, Lai CY, et al., 2015, PVDF/palygorskite composite ultrafiltration membranes with enhanced abrasion resistance and flux, JOURNAL OF MEMBRANE SCIENCE, Vol: 495, Pages: 91-100, ISSN: 0376-7388
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- Citations: 41
Wang C, Liu X, Chen JP, et al., 2015, Superior removal of arsenic from water with zirconium metal-organic framework UiO-66, Scientific Reports, Vol: 5, ISSN: 2045-2322
In this study, water stable zirconium metal-organic framework (UiO-66) has been synthesized and for the first time applied as an adsorbent to remove aquatic arsenic contamination. The as-synthesized UiO-66 adsorbent functions excellently across a broad pH range of 1 to 10, and achieves a remarkable arsenate uptake capacity of 303 mg/g at the optimal pH, i.e., pH = 2. To the best of our knowledge, this is the highest arsenate As(V) adsorption capacity ever reported, much higher than that of currently available adsorbents (5–280 mg/g, generally less than 100 mg/g). The superior arsenic uptake performance of UiO-66 adsorbent could be attributed to the highly porous crystalline structure containing zirconium oxide clusters, which provides a large contact area and plenty of active sites in unit space. Two binding sites within the adsorbent framework are proposed for arsenic species, i.e., hydroxyl group and benzenedicarboxylate ligand. At equilibrium, seven equivalent arsenic species can be captured by one Zr₆ cluster through the formation of Zr-O-As coordination bonds.
Li K, Chong JY, Aba NFD, et al., 2015, UV-enhanced sacrificial layer stabilised graphene oxide hollow fibre membranes for nanofiltration, Scientific Reports, Vol: 5, ISSN: 2045-2322
Graphene oxide (GO) membranes have demonstrated great potential in gas separation and liquid filtration. For upscale applications, GO membranes in a hollow fibre geometry are of particular interest due to the high-efficiency and easy-assembly features at module level. However, GO membranes were found unstable in dry state on ceramic hollow fibre substrates, mainly due to the drying-related shrinkage, which has limited the applications and post-treatments of GO membranes. We demonstrate here that GO hollow fibre membranes can be stabilised by using a porous poly(methyl methacrylate) (PMMA) sacrificial layer, which creates a space between the hollow fibre substrate and the GO membrane thus allowing stress-free shrinkage. Defect-free GO hollow fibre membrane was successfully determined and the membrane was stable in a long term (1200 hours) gas-tight stability test. Post-treatment of the GO membranes with UV light was also successfully accomplished in air, which induced the creation of controlled microstructural defects in the membrane and increased the roughness factor of the membrane surface. The permeability of the UV-treated GO membranes was greatly enhanced from 0.07 to 2.8 L m-2 h-1 bar-1 for water, and 0.14 to 7.5 L m-2 h-1 bar-1 for acetone, with an unchanged low molecular weight cut off (~250 Da).
Gil AG, Wu Z, Chadwick D, et al., 2015, Ni/SBA-15 Catalysts for combined steam methane reforming and water gas shift-Prepared for use in catalytic membrane reactors, APPLIED CATALYSIS A-GENERAL, Vol: 506, Pages: 188-196, ISSN: 0926-860X
Lee M, Wu Z, Wang B, et al., 2015, Micro-structured alumina multi-channel capillary tubes and monoliths, JOURNAL OF MEMBRANE SCIENCE, Vol: 489, Pages: 64-72, ISSN: 0376-7388
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- Citations: 30
Othman NH, Wu Z, Li K, 2015, An oxygen permeable membrane microreactor with an in-situ deposited Bi<sub>1.5</sub>Y<sub>0.3</sub>Sm<sub>0.2</sub>O<sub>3-δ</sub> catalyst for oxidative coupling of methane, JOURNAL OF MEMBRANE SCIENCE, Vol: 488, Pages: 182-193, ISSN: 0376-7388
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- Citations: 44
Kelsall GH, Kleiminger L, Li K, et al., 2015, Syngas (CO-H₂) production using high temperature micro-tubular solid oxide electrolysers, Electrochimica Acta, Vol: 179, Pages: 565-577, ISSN: 1873-3859
CO₂ and/or H₂O were reduced to CO/H₂ in micro-tubular solid oxide electrolysers with yttria-stabilized zirconia (YSZ) electrolyte, Ni-YSZ cermet cathode and strontium(II)-doped lanthanum manganite (LSM) oxygen-evolving anode. At 822 °C, the kinetics of CO₂ reduction were slower (ca. −0.49 A cm−2 at 1.8 V) than H₂O reduction or co-reduction of CO₂ and H₂O, which were comparable (ca. −0.83 to −0.77 A cm−2 at 1.8 V). Performances were improved (−0.85 and −1.1 A cm−2 for CO₂ and H₂O electrolysis, respectively) by substituting the silver current collector with nickel and avoiding blockage of entrances to pores on the inner lumen of micro-tubes induced by silver paste applied previously to decrease contact losses. The change in current collector materials increased ohmic potential losses due to substituting the lower resistance Ag with Ni wire, but decreased electrode polarization losses by 80–93%. For co-electrolysis of CO₂ and H₂O, isotopically-labelled C¹⁸O₂ was used to try to distinguish between direct cathodic reduction of CO₂ and its Ni-catalysed chemical reaction with hydrogen from reduction of steam. Unfortunately, oxygen was exchanged between C¹⁸O₂ and H₂¹⁶O, enriching oxygen-18 in the steam and substituting oxygen-16 in the carbon dioxide, so the anode off-gas isotopic fractions were meaningless. This occurred even in alumina and YSZ tubes without the micro-tubular reactor, i.e. in the absence of Ni catalyst, though not in quartz tubes. Unfortunately, larger differences between the thermal expansion coefficients of quartz and YSZ precluded using a quartz tube to house the micro-tubular reactor. However, the kinetic results, CO/H₂ yields from off-gas analysis, diffusional considerations and model predictions of reactant and product gas adsorption on Ni suggested that syngas should be produced by electrochemical reduction of steam to H₂, followed by its Ni-catalysed chemical reaction with CO₂
Gil AG, Wu Z, Chadwick D, et al., 2015, A catalytic hollow fibre membrane reactor for combined steam methane reforming and water gas shift reaction, Chemical Engineering Science, Vol: 137, Pages: 364-372, ISSN: 0009-2509
A catalytic hollow fibre membrane reactor (CHFMR) was developed in this study for combined steam methane reforming (SMR) and water gas shift (WGS) reaction. This is achieved by incorporating a Ni/SBA-15 catalyst into a plurality of micro-channels with open entrance from inner surface of Al2O3 hollow fibres, followed by coating of a 3.3 µm Pd membrane on the outer surface of the hollow fibre using an electroless plating method. In addition to systematic characterizations of each reactor component, i.e. Ni/SBA-15 catalyst, micro-structured ceramic hollow fibre and Pd separating layer, the effect of how the reactor was assembled or fabricated on the catalytic performance was evaluated. Electroless plating of the Pd membrane impaired the catalytic performance of the deposited Ni/SBA-15 catalyst. Also, the over-removal of hydrogen from the reaction zone was considered as the main reason for the deactivation of the Ni-based catalyst. Instead of mitigating such deactivation using “compensating” hydrogen, starting the reaction at higher temperatures was found more efficient in improving the reactor performance, due to a better match between hydrogen production (from the reaction) and hydrogen removal (from the Pd membrane). An effective methane conversion of approximately 53%, a CO2 selectivity of 94% and a H2 recovery of 43% can be achieved at 560 °C. In order for a more significant “shift” phenomenon, alternative methodology of fabricating the reactor and more coke resistant catalysts are recommended.
Aba NFD, Chong JY, Wang B, et al., 2015, Graphene oxide membranes on ceramic hollow fibers - Microstructural stability and nanofiltration performance, JOURNAL OF MEMBRANE SCIENCE, Vol: 484, Pages: 87-94, ISSN: 0376-7388
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Liu X, Demir NK, Wu Z, et al., 2015, Highly water-stable zirconium metal–organic framework UiO-66 membranes supported on alumina hollow fibers for desalination, Journal of the American Chemical Society, Vol: 137, Pages: 6999-7002, ISSN: 0002-7863
In this study, continuous zirconium(IV)-based metal–organic framework (Zr-MOF) membranes were prepared. The pure-phase Zr-MOF (i.e., UiO-66) polycrystalline membranes were fabricated on alumina hollow fibers using an in situ solvothermal synthesis method. Single-gas permeation and ion rejection tests were carried out to confirm membrane integrity and functionality. The membrane exhibited excellent multivalent ion rejection (e.g., 86.3% for Ca2+, 98.0% for Mg2+, and 99.3% for Al3+) on the basis of size exclusion with moderate permeance (0.14 L m–2 h–1 bar–1) and good permeability (0.28 L m–2 h–1 bar–1 μm). Benefiting from the exceptional chemical stability of the UiO-66 material, no degradation of membrane performance was observed for various tests up to 170 h toward a wide range of saline solutions. The high separation performance combined with its outstanding water stability suggests the developed UiO-66 membrane as a promising candidate for water desalination.
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