Flux and antifouling properties of mixed matrix membranes (MMMs) are yet to attain satisfactory status. The objective of this study is to find a method for mitigating the biofouling of poly(ether sulfone) (PES) ultrafiltration membranes via blending of thermoexfoliated vermiculite (VMT). Flow cytometry analysis shows that the behaviors of Bacillus subtilis 168 as a Gram-positive bacterium and Escherichia coli DH5 alpha as a Gram-negative bacterium were different. Hence, cell property is a suspected contributory factor in biofilm formation. Accordingly, considering the local predominant bacterial strains, a regionally customized membrane could scientifically be an expert solution for biofouling mitigation. Fabricated composite membranes have shown a higher flux compared to control PES membrane. Among all composite membranes, the PES-VMT0.10 had the highest flux of 476.4 L/(m2 h) (LMH) before fouling, and the highest flux of 210.7 LMH after three cycles of usage. In addition, the rejection rate of the PES-VMT0.15 The bovine serum albumin (BSA) sample was >77%, while that of the PES-VMT0.10 was >84%. The results of the static BSA adsorption test and the bacterial attachment test indicated that the membranes with macro-roughness on their surface showed better antibiofouling resistance. The antifouling properties of the modified membranes were also improved, because of their optimal wettability. On one hand, the hydrophilicity of membranes caused damaging both Gram-positive and Gram-negative bacteria and bacteriocidal effect. On the other hand, BSA adsorption and bacterial attachment on the membrane surface were affected by pore diameter.Keywords: antibacterial; biofouling; mixed matrix membrane; thermoexfoliated vermiculite; ultrafiltration;

•Overview of the recent development of graphene oxide pervaporation laminates.•Methods of the preparation of graphene oxide laminates.•Water vapor transport of graphene oxide laminates.•Outlooks of the future application of graphene oxide laminates in pervaporation.As a well-known one-atom thick nanosheets with preeminent physicochemical properties, graphene and its derivatives (e.g., graphene oxide, GO) have shown great potential on the membrane separation filed. This paper presents an update of GO laminates developments, including the membrane preparation methods, physicochemical properties and water vapor transport of GO laminates, and their application in pervaporation process. The possible strategies for the GO laminates into the practical application are also discussed. Finally, possible future researches about GO laminates for PV are also discussed.

As a subclass of metal–organic framework materials, zeolitic imidazolate frameworks (ZIFs) have exhibited great potential for numerous applications because of their special three-dimensional structure. Up to now, utilizing ZIF membranes for liquid separations is still limited because it is very difficult to select suitable materials and to fabricate integrated membranes. In this work, a modified contra-diffusion method was carried out to prepare ZIF-71 hollow fiber membranes. The metals Zn2+ and the organic links imidazole would meet and react on the interface of ceramic hollow fiber through diffusion. The as-prepared ZIF-71 membrane exhibits good performance in separation of ethanol–water mixtures.Keywords: contra-diffusion; hollow fiber; membrane; separation; ZIF-71

•Hollow fiber modules of ceramic-supported PDMS composite membranes were constructed.•Packing density and cross-section layout remarkably determined module performance.•Hollow fiber module showed a high and stable performance for bio-butanol recovery.The practical application of hollow fiber membranes for pervaporation technology has been received growing attention in recent years. This work reports the development of hollow fiber modules of ceramic-supported polydimethylsiloxane (PDMS) composite membranes applied for pervaporation process. Computational fluid dynamics (CFD) technique was used to simulate and optimize the flow field distribution in the modules with different packing density and cross-section layout. The hollow fiber modules with proposed configurations were fabricated in our lab and evaluated by pervaporation measurement in model butanol aqueous solution and real fermentation broth. The results suggested that the design of packing density and cross-section layout could realize the optimization of module configuration. The optimized module filled with 7 bundles of hollow fiber membranes at a high packing density of 560 m2/m3 exhibits a high and stable performance in the real ABE fermentation broth during 120 h continuous operation at 40 °C. The average total flux was 1000 g/m2 h and separation factor were 6.4 for ethanol, 22.2 for butanol and 28.6 for acetone, respectively. Our results demonstrated that the hollow fiber modules developed in this work could be competitive candidates for the practical application in pervaporation recovery of bio-butanol.

A three-dimensional NbO-type metal–organic framework (MOF) is composed of paddle-wheel-type dinuclear Cu2 secondary units and 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate (EBTC4−) linkers. Two types of nanometer-sized cavities are formed in this framework with ca. 8.5 Å in diameter for the small one and dimensions of ca. 8.5 × 8.5 × 21.5 Å for the larger and irregular elongated cavity. The guest molecules, H2O, DMF and DMSO, occupy the cavities of the as-prepared MOF crystal (labeled as MOF 1). MOF 2 was obtained by the guest-exchange approach using CH3OH, and the H2O and CH3OH molecules reside in the cavities of 2. Two MOFs show greenish-turquoise color at ambient temperature due to the d–d transition of Cu2+ ions in the framework, and the reversible thermochromic behavior owing to the change of the coordination environment of Cu2+ ions with varying temperatures. The films of 1 and 2 were fabricated on the α-Al2O3 and SiO2 supports by the seeded growth method, displaying similar reversible thermochromic behavior to the corresponding MOFs. This study suggested the possibility of novel thermochromic materials in the rational design of MOFs.

A three-dimensional (3D) microarray of a gold modified electrode with a nanoporous surface was successfully fabricated in this work. The special gold micro/nanostructure possessed an extremely high surface area (ca. 20 times its geometrical area), as well as highly stable and easily chemically modified properties, which could distinctly increase the binding sites for biological probes, facilitate the diffusion profile and enhance the electron transfer. Owing to these advantages, an ultrasensitive biosensor was designed on the porous microarray of the gold modified electrode (PMGE), which realized the simultaneous assay of cancer biomarkers of angiogenin (Ang) and thrombin (Tob). Under optimal experimental conditions, an impressively ultralow detection limit of 0.07 pM for Ang (a linear range from 0.2 pM to 10 nM) and a limit of 20 fM for Tob (a linear range from 50 fM to 5 nM) were obtained. Besides, the fabricated biosensor showed an excellent stability, good reproducibility and a high selectivity towards other biological proteins, which also exhibited promising potential for the application in a real serum sample analysis. Such a micro/nanostructure of gold could have widespread applications in biological sensing and quantitative biochemical analysis.

Because of the emerging scarcity of oil resources and the demand for environmental protection, as a typical biofuel, biobutanol produced by biomass fermentation is critical for the development of renewable energy. Pervaporation is considered to be an attractive separation technology for both the recovery of butanol from fermentation broth and the dehydration of butanol from low-water content solutions. Thus, as the core of the pervaporation process, pervaporation membranes, including organophilic membranes and hydrophilic membranes, are employed for the separation purpose. This article aims at reviewing the recent research progress in pervaporation membranes involved in biobutanol production. Both polymeric and inorganic membranes are discussed in terms of their design, fabrication, modification, morphology, structure, pervaporation performance, process, etc. A summary of the current state and perspectives of future development of pervaporation membranes for producing biobutanol is also made.Keywords: Butanol; Dehydration; Hydrophilic membrane; Organophilic membrane; Pervaporation; Recovery

A three-dimensional metal–organic framework compound with a formula [Cu2(EBTC)(H2O)2·8H2O·DMF·DMSO]∞ (EBTC = 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate) shows novel three-step dielectric relaxations arising from the orientational motion of dipolar guest molecules and its guest-free framework displays low-κ dielectric permittivity.

•PEBA containing Zn(BDC)(TED)0.5 particles MMMs were designed for butanol separation.•The incorporation of Zn(BDC)(TED)0.5 enhanced both separation factor and flux.•Feed temperature and concentration have positive effects on separation performance.•The MMMs exhibited high butanol separation performance in model ABE solution.Metal–organic frameworks (MOFs) containing mixed matrix membranes have recently received increasing attention because of the favorable compatibility with polymer chains. In this work, Zn(BDC)(TED)0.5 (BDC = benzenedicarboxylate, TED = triethylenediamine) particles were synthesized and introduced into polyether-block-amide (PEBA) to prepare mixed matrix membrane without interphase defects for bio-butanol recovery via pervaporation. The incorporation of fillers resulted in a decreased surface-free energy and improved mechanical properties. The effects of Zn(BDC)(TED)0.5 loading as well as operation conditions on pervaporation performance were systematically investigated and the MMMs with 20 wt% loading showed superior performance. Considering the practical application, the MMMs with 20 wt% Zn(BDC)(TED)0.5 was evaluated in ABE model solution, and it exhibited high n-butanol separation performance. This work suggests a promising future of Zn(BDC)(TED)0.5/PEBA MMMs for bio-butanol recovery via pervaporation process.

•An ultrasensitive and selective electrochemical Hg2+ biosensor was developed.•Ordered density-controllable metal-organic microarray was served as substrate.•Nicking endonuclease assisted cycling amplified the SWV signal change.•The E-DNA biosensor exhibited practical application in real samples.A novel electrochemical Hg2+ biosensor was developed on the basis of a metal-organic hybrid microarray, in which the nicking endonuclease (NE) assisted target-triggered strand release strategy was realized via the DNA cyclic amplification technique. The metal-organic hybrid microarray was fabricated using the SAM of 1, 4-benzenendithiol as soft template, and the density of the microarray could be adjusted by controlling the surface coverage of 1,4-benzenendithiol molecules. In the presence of Hg2+, capture DNA (cDNA) with an indicator at one end could hybridize with the reporter DNA (rDNA) through the stable T–Hg2+–T linkage, forming the nicking recognition site. After the nicking reaction, the electrochemical indicator dissociated from the electrode surface. The released rDNA and Hg2+ could be reused in the sensing system and initiate the next cycle, and more electroactive indicator dissociated from the electrode surface, resulting in a significant signal decrease. The constructed DNA biosensor could detect Hg2+ in a wide linear range from 15 pM to 500 nM, with an ultrasensitive detection limit of 5 pM (S/N=3). Furthermore, the biosensor exhibited excellent stability, good reproducibility and high selectivity towards other divalent ions. The proposed sensing system also showed a promising potential for the application in real aquatic product sample analysis.

•A single layered nano-grid structure of graphene was first synthesized.•This special film can uniformly distribute proteins in its homogenous cavities.•Various proteins can all be appropriately distributed with different categories and amount.•Sensitivities of prepared biosensors can enhance three times than random enzyme immobilization.In order to realize the protein uniform immobilization, a 3D nano-gird architecture of thiol grafted graphene film was fabricated to serve as a novel linker between protein and substrate. Relied on the online monitor by QCM, graphene deposition process can be exactly controlled to construct the perfect and continuous cavities with the consistent size of 500 nm. The synergetic characterization of FESEM and Nano-indentation characterizations have revealed the strong stability of grid structure to provide a firm foundation for further protein adsorption. Instead of common partial aggregation behavior, proteins can be spontaneously distributed into cavities by the interaction from thiol group. According to the verifications of various proteins, the efficiency of this distributor will not be constricted by the category and amount of protein, which exhibit its versatility of homogeneous distribution. Glucose and lactate oxidase loaded graphene distributors were directly served as biosensors to verify the superiority of distribution. Their sensitivities can be remarkably improved three times since the adoption of this nano-grid structured graphene distributor.

Highly oriented growth of a hybrid microarray was realized by a facile template-free method on gold substrates for the first time. The proposed formation mechanism involves an interfacial structure-directing force arising from self-assembled monolayers (SAMs) between gold substrates and hybrid crystals. Different SAMs and variable surface coverage of the assembled molecules play a critical role in the interfacial directing forces and influence the morphologies of hybrid films. A highly oriented hybrid microarray was formed on the highly aligned and vertical SAMs of 1,4-benzenedithiol molecules with rigid backbones, which afforded an intense structure-directing power for the oriented growth of hybrid crystals. Additionally, the density of the microarray could be adjusted by controlling the surface coverage of assembled molecules. Based on the hybrid microarray modified electrode with a large specific area (ca. 10 times its geometrical area), a label-free electrochemical DNA biosensor was constructed for the detection of an oligonucleotide fragment of the avian flu virus H5N1. The DNA biosensor displayed a significantly low detection limit of 5 pM (S/N = 3), a wide linear response from 10 pM to 10 nM, as well as excellent selectivity, good regeneration and high stability. We expect that the proposed template-free method can provide a new reference for the fabrication of a highly oriented hybrid array and the as-prepared microarray modified electrode will be a promising paradigm in constructing highly sensitive and selective biosensors.

For the first time, a ZIF-8 membrane was grown on the inner surface of a ceramic hollow fiber via cycling precursors. The inner-side hollow fiber ZIF-8 membrane exhibits good performance for recovering hydrogen.

A ferroelectric MOF with a formula [Sr(μ-BDC)(DMF)]∞ (1) was transformed into [Sr(μ-BDC)(CH2Cl2)x]∞ (2) using a solvent exchange approach, where DMF = N,N-dimethylformamide and BDC2− = benzene-1,4-dicarboxylate. The lattice solvents, CH2Cl2 molecules, in 2 were removed by heating to give the solvent-free metal–organic framework [Sr(μ-BDC)]∞ (3) and the crystal-to-crystal transformation is reversible between 1 and 3. The release of DMF molecules from 1 results in the metal–organic framework of [Sr(μ-BDC)]∞ expanding a little along the a- and b-axes. The crystal structure optimizations for 1 and 3 disclosed that the lattice expansion is associated with the alternations of the bond distances and angles in the Sr2+ ion coordination sphere along the a- and b-axes directions. The metal–organic framework 3 collapses at temperatures of more than 600 °C; such an extremely high thermal stability is related to the closed-shell electronic structure of the Sr2+ ion, namely, the coordinate bond between the closed-shell Sr2+ ion and the bridged BDC2− ligands does not have a preferred direction, which is favored for reducing lattice strains and is responsible for the higher thermal stability. The comparative investigations for the dielectric and ferroelectric behaviors of 1 and 3 confirmed that the motion of the polar DMF molecules, but not the [Sr(μ-BDC)]∞ framework, is responsible for the ferroelectric properties of 1.

•Metal-carboxylate system MOF membranes were fabricated by reactive seeding method.•As-prepared MOF membranes were defect-free and fine inter-grown.•The MOF membranes exhibited good selectivity for H2/N2 (19.1) and H2/CH4 (14.5).A novel metal-carboxylate system metal–organic frameworks ([Zn2(cam)2dabco] (Zn-CD)) membrane was synthesized on porous ZnO support and used for gas separation. XRD and SEM were used to characterize the structure, composition, and morphology of the membrane. The results proved that the uniform Zn-CD seeding layer and continuous Zn-CD membrane were effectively achieved by reactive seeding method. Through optimizing the preparation process, the integrated Zn-CD membrane was obtained. The single and binary gas permeations of the Zn-CD membranes were systematically investigated. The separation factors of H2/N2 and H2/CH4 gas mixture reach to 19.1 and 14.5, respectively, indicating that the Zn-CD membranes are defect free and have great potential applications for hydrogen separation.Graphical abstract

•A PB–TiO2 composite film was in-situ prepared by an aerosol co-deposition approach.•Micro-cubic PB and nano-round TiO2 double structures were obtained in one step.•As-prepared biosensor can exhibit ultrasensitivity in H2O2 detection.•High performance is due to the band gap extinction of TiO2.Assisted by the aerosol co-deposition approach, Prussian blue (PB)–TiO2 composite film can be in-situ formed in one step. The architecture of this film is constructed by two layers: PB–TiO2 nano-particles as a ground layer and individual PB micro-cubes as a top layer. Together with the strong electrocatalytic ability from regular PB morphology, TiO2 can denote its high catalysis in H2O2 detection attributed by the extinction of band gap since the combination of PB. Under a low operation potential −0.05 V, this sensor exhibits an ultrasensitive ability (1726.8 μA mM−1 cm−2), stability and low detection limit (1.5 μM) in H2O2 analysis. The application of this composite material is hopeful to extend in complex physiological analysis, and the preparation approach is promising to extend in more composite materials in-situ synthesis.

•Hierarchically aloe-like gold structure (HAG) is prepared by an electrochemical method.•The formation of the HAG involves a nucleation and three-dimensional growth process.•The HAG possesses a hydrophilic surface with large effective area.•A DNA biosensor with excellent performances is constructed on the HAG.Well-defined hierarchically aloe-like gold micro/nanostructures (HAG) are one-step electrochemically fabricated without introducing any template or surfactant. The formation kinetics of the HAG can be described as a nucleation and three-dimensional growth process controlled by the reactant diffusion from the solution side. As the applied electro-deposition potential moved in the negative direction, the gold crystal density increased, and the crystal shape changed from a quasi-spherical to dendritic fractal morphology. Under the optimal potential of −0.1 V and the time of 10 min, well-defined HAG possessing a hydrophilic surface with large effective area (ca. 8 times of its geometrical area) were obtained, which was used as the substrate for fabricating an ultrasensitive DNA biosensor. The DNA biosensor displayed a significantly enhanced detection limit of 12 aM, a wide linear response from 50 aM to 1 pM, as well as good selectivity, stability and reusability. This efficient DNA molecule immobilization platform may have implications in the preparation of many other gold micro/nanostructures (GMNs) with interesting properties and application potentials in many fields, such as biosensing, biocatalysis and biofuel cells.

A single layer Prussian blue (PB) grid was constructed on a Pt substrate using a self-assembly approach with nanosphere lithography in order to create a matrix for the uniform and ordered immobilization of proteins. Enzymes were captured in the cavities of the PB grid with the aid of an alkoxy silane linker, which enabled strong interaction between the silane's alkoxy groups and Pt. Using a low applied potential of −0.1 V vs. Ag/AgCl the as-prepared biosensors exhibited excellent performance in the detection of glucose, lactate and glutamate, indicating the versatile application of this specific PB architecture in the area of biosensors.

Metal–organic frameworks (MOFs) are ideal micro- and mesoporous materials for molecular separation. A defect-free MOF membrane supported on a porous substrate is required for high separation performance, however it is rather difficult to eliminate the micro-defects or intercrystalline gaps in the membranes. In this work, a ZIF-78 membrane was synthesized on a porous ZnO support. The defect formation mechanism in the membrane was illustrated by in situ thermal expansion analysis. A novel strategy was proposed to eliminate not only the macroscopic defects but also the intercrystalline gaps in the membrane by controlling the diffusion of solvent molecules through the channels of the ZIF-78 crystal. The ZIF-78 membrane exhibited high performance in separating H2. The ideal selectivity and mixture separation factor of H2–CO2 are 11.0 and 9.5, respectively. The approach reported in this paper offers an efficient and universal strategy for the facile synthesis of high-quality MOF membranes on porous supports.

High sensitivity and accuracy are strongly required for biosensors due to their special application in the life and health of humans. In order to greatly enhance the above two parameters of the prepared biosensor, the architectures of Prussian blue and Au were purposefully designed. A single layer of PB grid with tight nano-holes was constructed to serve as a mould for the constraint of further Au deposition. Based on the steric hindrance effect, the Au crystal can be pushed towards one direction to in situ form a shape of a micro-cypress. Under a very low operation potential, −0.05 V, this composite film has been confirmed to own excellent abilities of performance enhancement and anti-interference as a glucose biosensor. This synthesis strategy can be expected to provide inspiration for morphology control of materials and high performance development of biosensors.

For the first time, a homochiral metal–organic framework membrane was prepared for the enantioselective separation of important chiral compounds, especially chiral drug intermediates, which will allow for the potential development of a new, sustainable and highly efficient chiral separation technique.

Highly-effective sustainable hydrogen production from ethanol and water was achieved in a tubular dense mixed-conducting oxygen permeable membrane reactor, in which water splitting took place at the tube side of the membrane and oxidative steam reforming of ethanol occurred at the shell side simultaneously.

Mixed-conducting dense ceramic membranes have attracted considerable attention because of their potential application in oxygen separation, oxyfuel combustion and catalytic membrane reaction processes. However, the development of robust mixed-conducting membranes with both high permeability and stability is still a major challenge. In this paper, a crack-free asymmetric tubular membrane made of SrCo0.4Fe0.5Zr0.1O3−δ perovskite oxide was successfully prepared by a combined spin-spraying and co-sintering method, in which the slurry containing powders was sprayed on a rotating green support tube and followed by sintering process. The issue of the shrinkage mismatch between membrane and support was solved by the optimization of processing parameters, i.e. heating rate, sintering temperature and spraying circles. SEM and nitrogen gas-tight test demonstrated that the surface of membrane was dense, continuous and crack-free, and the thickness of the dense layer was about 20 μm. A high oxygen flux of 7.41×10−7 mol cm−2 s−1 was achieved at 800 °C which was 2.35 times that of symmetric membrane. Long-term oxygen permeation measurement (850 °C, 200 h) showed that the asymmetric membrane was stable under low oxygen partial pressure environment. This work provides a new path for the preparation of asymmetric tubular membrane. This simple and cost-effective fabrication technique can be readily used for mass production.Highlights▸ Asymmetric tubular SCFZ membrane was prepared by spin-spraying and co-sintering. ▸ Dense and crack-free SCFZ layer with a uniform thickness of 20 μm was obtained. ▸ Thin membrane layer improves the oxygen flux and decreases the permeation activation energy.

A new series of Nb2O5-doped (0.5, 1, 3, 5, 10 and 15 wt.%) SrCo0.8Fe0.2O3−δ (SCF) mixed conducting materials have been synthesized by the solid-state reaction method. The crystal structure, phase stability, oxygen desorption behavior, thermal expansion behavior, electrical conductivity and oxygen permeability of the prepared materials were systematically investigated. Doped Nb2O5 was completely incorporated into the SCF structure and effectively suppressed the coexisting orthorhombic phase in bulk cubic SCF and the perovskite–brownmillerite transition under low oxygen partial pressure. In situ high-temperature X-ray diffraction (HTXRD) also indicated good chemical and structure stability of the slightly doped Nb2O5 (0.5 wt.%) at both 0.21 × 105 and 1 × 10−2 Pa oxygen partial pressures at high temperatures. Nb2O5 dissolved into the SCF lattice served to some extent to decrease the electrical conductivity and oxygen flux, and increase the thermal expansion. The grain size of the membranes were significantly suppressed by the doping of Nb2O5. In particular, SCFNb0.5 with the cubic perovskite structure has the smallest cell parameters, the lowest thermal expansion and the highest oxygen flux.Graphical abstractHighlights► Nb2O5-doped SrCo0.8Fe0.2O3−δ materials were prepared as oxygen permeable membrane. ► Single perovskite structure of Nb2O5-doped SrCo0.8Fe0.2O3−δ oxides. ► Nb2O5 stabilizes the perovskite structure of SCF under low oxygen partial pressure. ► Slight dopant greatly promotes the oxygen flux at both high- and low-temperature.

Metal–organic framework (MOF) membranes have attracted great attention for their potential applications in gas and liquid separations. Recently, we have developed a novel reactive seeding (RS) method for the synthesis of MOF membranes, such as MIL-53 and MIL-96 membranes, on porous inorganic supports. By the RS method, a homogeneous seeding layer well bonding with the support could be formed for the secondary hydrothermal synthesis of high-quality MOF membranes. Our previous study demonstrated the RS approach was of versatility. However, the formation mechanism of MOF membranes derived from RS approach is unclear. In this work, taking MIL-96 as an example, we investigated the interactions between support and organic precursor and the differences between in situ synthesis and RS route. A formation mechanism of RS method was proposed. Based on the mechanism, the α-Al2O3 firstly reacted with H2O to produce γ-AlO(OH), and then the γ-AlO(OH) interacted with H3btc to form the MIL-96 seed crystals.Graphical abstractHighlights► A formation mechanism of MIL-96 membrane derived from reactive seeding approach was proposed. ► The α-Al2O3 support surface transforms into γ-AlO(OH), reacting with H3btc solution to form MIL-96 seeding layer. ► Secondary growth based on the seeding layer is robust to synthesize highly integrated MIL-96 membrane.

Ethyl acetate (EtAc) is an essential raw material widely used in the chemical industry. In this paper, a new reactive distillation (RD)–pervaporation (PV) coupled process for ethyl acetate (EtAc) production is proposed, in which the PV membrane is located in the bottom stream in order to selectively remove the water from the reboiler and recycle the acetic acid (HAc) into the feed. The main operating conditions of the RD process are discussed by experimental and simulation methods. The RD–PV coupled process was established by coupling the PVA/ceramic composite membrane with the RD reboiler. The effects of PV operating temperature and HAc/ethanol molar ratio on the RD performance are thoroughly discussed. It was found that the PVA/ceramic composite membrane exhibited good PV performance and stability with a total flux of 600 g·m–2·h–1 and a separation factor of 14 in 90 wt % HAc/water solution at 70 °C. Owing to the water removal and HAc recycle from the reboiler via PV, both the ethanol conversion and EtAc purity are remarkably improved, from 82.4 to 85.6 wt % and from 81.3 to 84.8%, respectively. This new RD–PV coupled process can be expected to be an effective and energy-saving way for ethyl acetate production.

In further purification of ethyl acetate (EAC) process, azeotropic distillation or extractive distillation is usually applied. High energy consumption limits the economic profit of the process. In this study, pervaporation separation of EAC/ethanol (EA)/water ternary mixtures using the ceramic-supported polyvinyl alcohol (PVA) composite membrane was investigated to substitute the azeotropic distillation or extractive distillation. Swelling experiments were performed to evaluate the sorption characteristic of the membrane. Flory-Huggins theory was applied to study the interaction between the membrane and the penetrant. The UNIFAC model was adopted to investigate the variation of the penetrant activity in the membrane. The effects of operation temperature, feed water content and feed flow rate on the PV performance of the membrane were systematically investigated. The composite membrane exhibited high PV performance with the total flux of 2.1 kg·m−2·h−1 and 94.9 wt% permeate concentration of water (operation condition: feed composition 82.6 wt% EAC, 8.4 wt% EA, 9 wt% water, feed temperature 60 °C, feed flow rate 252 mL· min−1). The PV performance of the membrane varied slightly over a continuous PV experiment period of 110 h. Our results demonstrated that the PVA/ceramic membrane was a potential candidate for the purification of EAC/EA/water ternary mixtures.

A highly thermally stable, polar MOF built from the rigid ligand benzene-1,4-dicarboxylate and the main-group metal ion Sr2+ shows ferroelectricity. With the ultimate goal of making components for use in devices, the fabrication of MOF thin films on Al2O3, SrAl2O4, and Al foil substrates using the in situ solvothermal method was explored. The mechanism of macroscopic polarization reversals in the ferroelectric MOF under an ac electric field and the dependence of the morphology of the MOF thin film on the nature of the substrate surface are discussed.

The morphology of a functional film, especially in the microscale or nanoscale, has been found to be critical for the performance of sensor materials. In this report, two shapes of PB crystals, microcubes and nanomastoids, were simultaneously formed using a self-assembly approach, induced by a weak electric field. This architecture exhibited an ultra-sensitive response in H2O2 detection (1922.3 mA M−1 cm−2). By consideration of the experimental results, a synergistic transmitting mechanism is provided to account for this high sensitivity, or the microcubes can fulfil the role of electron accumulation in electrocatalysis, and nanomastoids will fulfil the role of the main transport of electrons from the film to the Pt surface.

A facile reactive seeding (RS) method was developed for the preparation of continuous MOF membranes on alumina porous supports, in which the porous support acted as the inorganic source reacting with the organic precursor to grow a seeding layer.

Catalytic membrane reactors which carry out separation and reaction in a single unit are expected to be a promising approach to achieve green and sustainable chemistry with less energy consumption and lower pollution. This article presents a review of the recent progress of dense ceramic catalytic membranes and membrane reactors, and their potential applications in energy and environmental areas. A basic knowledge of catalytic membranes and membrane reactors is first introduced briefly, followed by a short discussion on the membrane materials including their structures, composition and strategies for material development. The configuration of catalytic membranes, the design of membrane reaction processes and the high temperature sealing are also discussed. The performance of catalytic membrane reactors for energy and environmental applications are summarized and typical catalytic membrane reaction processes are presented and discussed. Finally, current challenges and difficulties related to the industrialization of dense ceramic membrane reactors are addressed and possible future research is also outlined.

Based on positively charged poly(diallyldimethylammonium chloride) (PDDA) layer providing nucleation sites for the growth of PB via self-assemble process, regular Prussian Blue (PB) nanocubes was obtained on the Pt electrode by simply adjusting adsorption temperatures of PDDA. Electrochemical impedance spectroscopy (EIS) was applied to study the coverage and electrical resistance of PDDA on the electrode with different adsorbed temperatures. The evolutions of PB morphology with temperature-controlled PDDA were characterized by field emission scanning electron microscope (FESEM). Investigation on the electrochemical property of the modified electrodes was also carried out using Chronoamperometry. Control of temperature could optimize the charge density distribution of PDDA on electrode and further construct the regular growth of PB crystal. At the PDDA adsorbed temperature of 30 °C, the as-fabricated PB modified electrode showed an excellent sensitivity to hydrogen peroxide response of about 1179.6 mA M−1 cm−2, a rapid response time within 2 s, and a wide linear range up to 600 μM H2O2. In addition, the sensor exhibited good reproducibility and stability.Graphical abstractHighlights► Temperature was found to significantly affect the adsorption behavior of PDDA on electrode in the self-assembly of PB. ► Regular PB nanocubes could be achieved by controlling PDDA adsorption temperatures. ► The as-fabricated biosensor exhibited a high sensitivity of 1179.6 mA M−1 cm−2 for H2O2 detection.

Dehydration of ethyl acetate (EAC)–water mixtures by pervaporation (PV) was studied using a ceramic-supported polyvinyl alcohol (PVA) composite membrane. The effects of feed temperature, feed water content and feed flow rate on the PV performance of the membrane were systematically investigated. In addition, swelling experiments were performed to evaluate the sorption characteristic of the membrane. Flory-Huggins and NRTL (non-random two liquid) theories were applied to analyze the interactions of the membrane and penetrants and the mutual interaction between the penetrants. The membrane exhibited high PV performance, the water permeance and selectivity of water to EAC were 1.45 × 10−5 kg m−2 s−1 kPa−1 and 129, respectively, at 60 °C with the feed water content of 5.1 wt% and the feed flow rate of 252 mL min−1.Graphical abstractA PVA/ceramic composite pervaporation membrane was used in dehydration of ethyl acetate-water mixtures.Research highlights▶ PVA/ceramic composite membrane was used in separation of ethyl acetate-water mixtures. ▶ The PVA/ceramic composite membrane exhibited high pervaporation performance.

A novel dual-membrane reactor is proposed for heterogeneous catalysis over ultrafine catalyst particles. In this reactor, one tubular porous ceramic membrane is employed as a distributor controlling the supply of reactant, while the other is employed as a membrane separator for in situ separation of ultrafine catalysts from the products. To evaluate the feasibility and the performance of the dual-membrane reactor, phenol hydroxylation with hydrogen peroxide (H2O2) over TS-1 catalyst was selected as a model reaction. As compared to traditional H2O2 feeding modes, the use of the porous ceramic membrane distributor allows a uniform injection of H2O2 into the reaction system, and as a result significantly promotes the dihydroxybenzene selectivity. The phenol conversion and the DHB selectivity above 15% and about 95%, respectively, can be achieved in a continuous operation of 30 h. TS-1 catalysts can be retained almost completely in the reactor system by the membrane separator. Our study demonstrates the advantages of the novel dual-membrane reactor in enhancing selectivity and catalysts separation in a continuous heterogeneous catalytic reaction.

Metal−organic framework (MOF) membranes have attracted considerable attention because of their striking advantages in small-molecule separation. The preparation of an integrated MOF membrane is still a major challenge. Depositing a uniform seed layer on a support for secondary growth is a main route to obtaining an integrated MOF membrane. A novel seeding method to prepare HKUST-1 (known as Cu3(btc)2) membranes on porous α-alumina supports is reported. The in situ production of the seed layer was realized in step-by-step fashion via the coordination of H3btc and Cu2+ on an α-alumina support. The formation process of the seed layer was observed by ultraviolet−visible absorption spectroscopy and atomic force microscopy. An integrated HKUST-1 membrane could be synthesized by the secondary hydrothermal growth on the seeded support. The gas permeation performance of the membrane was evaluated.

The mixed ionic-electronic conducting (MIEC) materials that have been developed for catalytic membrane reactors are vulnerable to a reducing atmosphere, especially H2. We reported on a MIEC oxide, Sr0.7Ba0.3Fe0.9Mo0.1O3−δ (SBFM), with a cubic perovskite structure (a = 3.91 Å at room temperature). SBFM can maintain full perovskite structure in a 5 vol % H2/He atmosphere at 900 °C even for 50 h. The high reduce-tolerant property was mainly attributed to the synergistic effect between Mo(VI)/Mo(V) and Fe3+/Fe2+ couples. SBFM also exhibited good tolerance to a CO2 atmosphere at high temperature (≥900 °C) but reacted with CO2 at relatively low temperature (<800 °C). The introduction of Mo ion into the Fe site greatly improved the thermal stabilization of the SBFM oxide. The average thermal expansion coefficients in nitrogen atmosphere were 12.8 × 10−6 and 20.8 × 10−6 °C −1 in the temperature ranges of 200−600 and 600−900 °C, respectively. At 900 °C, the oxygen permeation flux of SBFM membrane (1 mm in thickness) was 4.39 × 10−7 mol cm−2 s−1. The oxygen permeation activation energy (Ea) was 42 kJ mol−1, which was significantly lower than that of commonly used MIEC membranes.

Prussian blue (PB) is considered as a promising material for electrochemical biosensors. However, the PB microstructure, which is essential for biosensor performance, is difficult to control on the electrode surface due to its rapid formation reaction. In this report, the growth of a regular nano-structured PB on the platinum (Pt) electrode surface was realized by an aerosol deposition approach without a template. The morphology of PB could be controlled well via deposition time and temperature, as characterized by cyclic voltammetry (CV), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The cuboid and cubic shapes of PB nano-crystals were formed at 25 and 35 °C, respectively. When the Pt electrode with nano-cubic PB was used to detect hydrogen peroxide, it exhibited a high sensitivity (1163 mA M−1 cm−2) and an excellent anti-interference to ascorbic acid. Our observations suggest that the proposed approach may be used for regular growth of crystals having rapid formation reaction, and the prepared amperometric biosensor will have potential applications in the detection of physiological substances.

A series of new oxides with the nominal composition of SmxSr1−xCo1−yCeyO3−δ (x = 0.1, 0.3, 0.5; y = 0.05, 0.1) were synthesized. Their crystal structure, morphology, thermal expansion and electrochemical properties were systematically investigated. A phase-pure perovskite-type Sm0.3Sr0.7Co0.95Ce0.05O3−δ oxide is obtained, while the other samples are actually composed of B-site cation deficient SmxSr1−xCo1−yCey−zO3−δ (0 < z < y) and CeO2 mixed phases. These two-phase samples exhibit larger oxygen nonstoichiometry (δ) and higher average thermal expansion coefficients (TEC), while the single-phase Sm0.3Sr0.7Co0.95Ce0.05O3−δ oxide shows a smaller δ and a lower TEC as compared to Sm0.3Sr0.7CoO3−δ. The introduction of cerium also effectively suppresses the chemical expansion and the growth of grain particles. The smaller grain size is beneficial in improving the electrode surface area. In addition, the electrical conductivities of Ce-doped SmxSr1−xCoO3−δ are all higher than 200 S cm−1. EIS tests demonstrate that partially substituting Co with Ce and the B-site deficiency improve the cathode performance. Sm0.3Sr0.7Co0.95Ce0.05O3−δ shows the lowest area specific resistance (ASR) among the others. Through proper cobalt-site cerium doping, the SmxSr1−xCoO3−δ related oxides could be developed into promising cathode materials for SOFC.

Ceramic-supported poly(vinyl alcohol)–chitosan composite membranes were prepared for pervaporation dehydration purpose. The microstructure, physicochemical properties and surface hydrophilicity of the composite membranes were systematically investigated. The composite membranes have been cross-linked successfully and the surface hydrophilicity decreased with the increase of chitosan content. Pervaporation dehydration of four organic/water mixtures was carried out to study the membrane performance. The pore size of ceramic support influenced the performance of the composite membrane greatly, and the ceramic membrane with the pore size of 0.2 μm is proper for the use as the support. It was found that chitosan played an important role in increasing the membrane permeation flux. When the chitosan content is 60 wt%, the composite membrane exhibited high performance. In the dehydration of alcohol/water mixtures, the permeation flux increased without a decrease in separation factor. This abnormal trend between flux and separation factor suggested that the non-deformable ceramic support had a restricted swelling effect on the composite membrane. In the dehydration of ester/water mixtures, the membrane exhibited excellent pervaporation performance, especially in the dehydration of ethyl acetate/water mixture at 3.5 wt% water in feed with a flux of 1250 gm−2 h−1 and a separation factor larger than 10,000.

A facile aerosol deposition approach, which was simulated as feasible by density functional theory (DFT), was applied to synthesize a Prussian Blue (PB) film directly on a Pt electrode surface.

A series of SrAl2O4 (3, 5, 7 and 9 wt.%, respectively) doped SrCo0.8Fe0.2O3−δ (SCF) mixed-conducting materials were prepared by a gel-combustion method and then a solid state reaction process. The crystal structure, thermal expansion behavior, microstructure, electrical conductivity, oxygen permeability and structure stability of these materials were systematic investigated. The prepared SrAl2O4-doped SCF oxides presented single-phase perovskite structure and no obvious impurity phases can be observed. The thermal expansion coefficients, electrical conductivity and oxygen permeability of these materials decreased with increasing the doping amount of SrAl2O4. 5–7 wt.% SrAl2O4 was proper to stabilize the perovskite structure of SCF at high temperature and under low oxygen partial pressures. 5 wt.% SrAl2O4-doped SCF (SCFSA5) membrane reactor was constructed for hydrogen production from methane. This membrane reactor exhibited high performance and good stability for hydrogen production. At 850 °C, the CH4 conversion, hydrogen selectivity, hydrogen production and oxygen permeation flux remained at about 75%, 91%, 25 ml(STP) cm−2 min−1 and 8 ml(STP) cm−2 min−1, respectively, for more than 1200 h.

In this communication, a hydrogen peroxide (H2O2) sensor based on self-assembled Prussian Blue (PB) modified electrode was reported. Thin film of PB was deposited on the electrode by self-assembly process including multiple sequential adsorption of ferric ions and hexacyanoferrate ions. The as-prepared PB modified electrode displayed sufficient stability for practical sensing application. At an applied potential of −0.05 V vs. Ag/AgCl (sat. KCl), PB modified electrode with 30 layers exhibited a linear dependence on H2O2 concentration in the range of 1 × 10−6–4 × 10−4 M (r = 0.9998) with a sensitivity of 625 mA M−1 cm−2. It was found that the sensitivity of H2O2 sensors could be well controlled by adjusting the number of deposition cycles for PB preparation. This work demonstrates the feasibility of self-assembled PB modified electrode in sensing application, and provides an effective approach to control the sensitivity of PB-based amperometric biosensors.

A glucose biosensor, which was based on self-assembled Prussian Blue (PB) modified electrode with glucose oxidase (GOD) immobilized in cross-linked glutaraldehyde matrix, was developed. Fourier-transform infrared spectroscopy shows that the immobilized GOD retains its native conformation. Cyclic voltammetry was used to examine the electrocatalytic property of the enzyme electrode. The prepared glucose biosensor exhibits fast response (<4 s) and low detection limit of 5 × 10−6 M. The calculated apparent Michaelis constant KM was 6.3 ± 1.2 mM, indicating a high affinity between the GOD and glucose. The effects of glutaraldehyde concentration and GOD loading on the sensitivity of the glucose biosensor have also been investigated. Under the optimal conditions, the biosensor shows a high sensitivity of about 80 mA M−1 cm−2 in a concentration range up to 1 × 10−3 M. The relative standard deviation (RSD) for intra-electrode and inter-electrode were 4% and 5%, respectively. In addition, the anti-interferent ability and stability of the biosensor were also discussed.

Coupling systems of nanocatalysis and membrane filtration (nanocatalysis/MF) are features of convenience for the in situ separation of nanocatalysts from the reaction mixture. In this work, a submerged nanocatalysis/MF system with a tubular ceramic membrane as the separation unit was developed for the liquid-phase hydrogenation of p-nitrophenol to p-aminophenol over nickel nanoparticles with various particle morphologies obtained by hydrogen annealing at different temperatures. We extensively characterized the nickel nanoparticles using X-ray diffractometry (XRD), nitrogen adsorption, transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), and we determined that the annealing temperature significantly influenced the particle size, specific surface area, and crystalline morphology of the nickel nanoparticles. We then evaluated the catalytic performance and separation efficiency of the submerged nanocatalysis/MF system. The nickel nanoparticles annealed at different temperature showed remarkably different catalytic activity, because of their specific structural properties. There was an unexpected nonlinear relationship between the nickel particle size and the flux, which was due to the changed nature of the cake layer formed on the membrane surface and a pore blocking effect. The results from both aspects of catalysis and separation performance indicated that the nickel nanoparticles annealed at 100 °C displayed a best balanced catalytic performance and separation efficiency for the submerged nanocatalysis/MF system.

Using a new nitrogen precursor of a mixture of ammonia and hydrazine hydrate, N-doped TiO2 photocatalyst with a high efficiency under visible light was synthesized by a precipitation method. The analysis of X-ray photoelectron spectroscopy (XPS) suggested that the doping concentration of nitrogen was 0.45 at%, while it was 0.21 at% or 0.24 at% using single ammonia or hydrazine hydrate as nitrogen precursor. The patterns of the electron paramagnetic resonance spectroscopy (EPR) indicated that the paramagnetic species of NO22−, NO and Ti3+ existed as the proposed active species. The ultraviolet–visible (UV–vis) spectra revealed that the band-gap of the N-doped TiO2 was 3.12 eV, which was slightly lower than 3.15 eV of pure TiO2. The N-doped TiO2 showed higher efficiency under both ultraviolet (UV) and visible light irradiations. Moreover, the degradation grade of 4-chlorophenol (4-CP) using the as-synthesized N-doped TiO2 under sunlight irradiation for 6 h was 82.0%, which was higher than 66.2% of the pure TiO2, 60.1% or 65.2% of the N-doped TiO2 using single ammonia or hydrazine hydrate as precursor. Density functional theory (DFT) calculations were performed to investigate the visible light response of the N-doped TiO2. Our study demonstrated that the visible activities vary well with the concentrations of NO22− species incorporated by N–TiO2 series photocatalysts and the higher activity of the as-prepared N-doped TiO2 was attributed to the enhancement of the concentration of NO22− species.

We used response surface methodology (RSM) to optimize the preparation conditions that had great effects on the performance of the polydimethylsiloxane (PDMS)/ceramic composite membranes for pervaporation. Good performance of membranes could be realized through manipulating three variables, which were polymer concentration, crosslink agent concentration, dip-coating time. In our study, we established the regression equations between the preparation variables and the performance of the composite membranes. We investigated main effects, quadratic effects and interactions of the three variables on the flux and the selectivity of composite membranes. The results showed that polymer concentration was the most significant variable that influenced the permeation flux and the selectivity among three variables and the experimental results were in good agreement with those predicted by the proposed regression models. At a feed temperature of 333 K under a pressure of 500 Pa in an ethanol concentration of 4.2 wt.%, the maximum flux of the 12.95 kg m−2 h−1 was obtained by employing the model under the following preparation conditions: polymer concentration 7.4 wt.%, crosslink agent concentration 10.6 wt.%, dip-coating time 60 s. One can expect to apply the regression equations in the preparation of PDMS/ceramic membranes and reasonably predict and optimize the performance of the composite membranes.

Effects of sintering atmospheres on properties of SrCo0.4Fe0.5Zr0.1O3−δ mixed-conducting membranes were in detail studied in terms of sintering behavior, electrical conductivity and oxygen permeability. The sintering atmospheres were 100% N2, 79% N2–21% O2, 60% N2–40% O2, 40% N2–60% O2, 20% N2–80% O2 and 100% O2 (in vol.%), and the prepared membranes were correspondingly denoted as S-0, S-21, S-40, S-60, S-80 and S  -100, respectively. It was found that the properties of membranes were strongly dependent on the sintering atmosphere. As the oxygen partial pressure in the sintering atmosphere (PO2PO2) increased, sintering ability, electrical conductivity and oxygen permeability decreased at first, which was in the order of S-0 > S-21 > S  -40. However, as PO2PO2 increased further, sintering ability, electrical conductivity and oxygen permeability increased gradually: S-40 < S-60 < S-80 < S-100. And the S-100 membrane had the best sintering ability, electrical conductivity and oxygen permeability in all membranes.

An asymmetric mixed-conducting membrane consists of a thin dense layer and a porous support, and its application has drawn considerable attention, because it is expected to have a more promising potential in the practical application compared with the symmetric membrane. However, with the introduction of support in the asymmetric membrane, two possible permeation modes are produced. One mode is that oxygen permeates from the support to the thin dense layer (designated as SD mode). The other is in the direction from the thin dense layer to the support (designated as DS mode). Thus, from the viewpoint of choosing an appropriate oxygen permeation mode to make better use of the membrane, it is necessary to study the oxygen flux in these two modes. In this paper, their effects on the oxygen flux of asymmetric membranes were investigated from the experiment and the model. The modeling results showed a good agreement with the experimental data. Our study demonstrates that when the asymmetric membrane adopts the SD mode, it is beneficial for the membrane to obtain higher oxygen permeation flux.

The thermal decomposition of CO2 to CO and O2 is a potential route for the consumption and utilization of CO2. However, this reaction is limited by both the thermodynamic equilibrium and the kinetic barrier. In this study, we reported an innovative catalytic process to decompose CO2 in an oxygen-permeation membrane reactor packed with a mixed-conducting oxide supported noble metal catalyst, or Pd/SrCo0.4Fe0.5Zr0.1O3−δ (Pd/SCFZ), which is of high activity in the decomposition of CO2 into CO and O2. Pd/SCFZ catalyst was prepared by incipient wetness impregnation of the SCFZ powders with an aqueous solution of PdCl2, and the CO2 sorption/desorption property was examined by in situ Fourier transform infrared spectroscopy and temperature-programmed desorption-mass spectrometry technologies. It was shown that there appeared a typical of bridged carbonyls (Pd-CO) on the surface of the Pd/SCFZ catalyst formed after CO2 decomposition. Both CO2 and CO could be detected in the species desorbed from Pd/SCFZ catalyst, which implied that the Pd/SCFZ catalyst could effectively activate the CO2 molecule. During the catalytic process, furthermore, the activity of the Pd/SCFZ catalyst can self-regenerate by removing the produced lattice oxygen through the dense oxygen-permeable ceramic membrane. At 900 °C, this catalytic process attains 100% of CO formation selectivity at 15.8% of CO2 conversions.

Experiments and density functional theory (DFT) calculations were combined in an attempt to investigate the origin of the differences in nitrogen concentration incorporated by N-doped TiO2. X-ray photoelectron spectroscopy (XPS), UV−vis diffusive reflectance spectra (UV−vis), and photodegradation experiments were conducted to set some premises for DFT calculations. Fourier transform infrared (FT-IR) spectroscopy was applied to investigate the NHx-containing species in the dried precipitate from the hydrolysis. [Ti(H2O)a(NH3)b(OH)cCld](4−c−d) (a + b + c + d = 6) is defined as the Ti complex produced by the hydrolysis process, and its pH-dependent character was further determined by Gibbs energy calculations for the reaction based on those of related equations. Adsorption energies of NO on TiO2 surfaces were calculated to study the ability of NOx to be incorporated into the TiO2 matrix under different pH conditions. Finally, we propose three processes as being responsible for the dependence of the nitrogen concentration on the pH value.

An organic–inorganic composite membrane was successfully prepared by means of electrostatic self-assembly of polyelectrolytes on silica sol–gel modified macroporous ceramic supports. The integrality of the as-prepared composite membrane was evaluated in pervaporation of ethanol/water mixtures. Membrane separation performance was optimized by studying the modification cycle, polyelectrolyte molecule structure, self-assemble conditions, thermal treatment conditions and operating temperatures. It was found that the polyelectrolyte molecule structure mainly affected the separation performance of the composite membrane after a two-cycle modification and raising pervaporation operating temperature was an efficient way to improve both membrane flux and water selectivity. The composite membrane deposited by 60 layer pairs of polyethylenimine/poly(vinyl sulfate) (PEI/PVS) showed a high flux of 18.4 kg m−2 h−1 and a water concentration enhancement from 6.2 to 35.3 wt.%. Our study demonstrates that the composite membrane prepared on macroporous ceramic support through our route is suitable for separation of liquid species at a molecular level.

Because of the emission of larger amount of CO2, power generation from fossil fuel has resulted in serious environmental problems. Integrating dense mixed-conducting membranes (MCMs) into power cycles with CO2 capture has been considered as the most advanced technology for high efficiency and clean power production. This paper presents an update of MCMs development efforts, including the recent progress in membrane materials and their chemical resistance; the membrane architecture especially the tubular asymmetric membranes and hollow fiber membranes; and the pilot-scale planar and membrane modules. The oxyfuel technique using MCMs for oxygen production and its commercial prospects are discussed. Finally, current challenges related to the industrialization of MCMs are addressed and possible future research is also outlined.Highlights► Mixed-conducting membrane materials with high permeability and structural stability for oxygen or hydrogen separation have been developed. ► The technology and process to fabricate ceramic membranes with desired geometry configurations are available. ► Commercial-scale planar ceramic membrane modules with the oxygen production rate of tonnage-quantity per day have been established and the further scale up technology is available. ► The pilot plant of ceramic membrane-based oxyfuel process for zero emission power generation has been constructed. ► Mixed-conducting membranes have shown new opportunities in high efficiency power generation with CO2 capture.

Heterogeneous catalysts with ultrafine or nano particle size have currently attracted considerable attentions in the chemical and petrochemical production processes, but their large-scale applications remain challenging because of difficulties associated with their efficient separation from the reaction slurry. A porous ceramic membrane reactor has emerged as a promising method to solve the problem concerning catalysts separation in situ from the reaction mixture and make the production process continuous in heterogeneous catalysis. This article presents a review of the present progress on porous ceramic membrane reactors for heterogeneous catalysis, which covers classification of configurations of porous ceramic membrane reactor, major considerations and some important industrial applications. A special emphasis is paid to major considerations in term of application-oriented ceramic membrane design, optimization of ceramic membrane reactor performance and membrane fouling mechanism. Finally, brief concluding remarks on porous ceramic membrane reactors are given and possible future research interests are also outlined.

Pervaporation (PV), as an environmental friendly and energy-saving separation technology, has been received increasing attention in recent years. This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes. The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane (PDMS) and hydrophilic poly(vinyl alcohol) (PVA), chitosan (CS) and polyelectrolytes. The effects of ceramic support treatment, polymer solution properties, interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed. Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion. The applications of these composite membranes in pervaporation process are summarized as well, which contain the bio-fuels recovery, gasoline desulfuration and PV coupled process using PDMS/ceramic composite membrane, and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane. Finally, a brief conclusion remark on polymer/ceramic composite membranes is given and possible future research is outlined.

Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m−2·h−1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.

Composite membranes have attracted increasing attentions owing to their potential applications for CO2 separation. In this work, ceramic supported polydimethylsiloxane (PDMS) and poly (ethylene glycol) diacrylate (PEGDA) composite membranes were prepared. The microstructure and physicochemical properties of the compositemembranes were characterized. Preparation conditions were systematically optimized. The gas separation performance of the as-prepared membranes was studied by pure gas and binary gas permeation measurement of CO2, N2 and H2. Experiments showed that PDMS, as silicone rubber, exhibited larger permeance and lower separation factors. Conversely, PEGDA composite membrane presented smaller gas permeance but higher ideal selectivity for CO2/N2. Compared to the performance of those membranes using polymeric supports or freestanding membranes, the two kinds of ceramic supported composite membranes exhibited higher gas permeance and acceptable selectivity. Therefore, the ceramic supported composite membrane can be expected as a candidate for CO2 separation from light gases.

For the first time, a ZIF-8 membrane was grown on the inner surface of a ceramic hollow fiber via cycling precursors. The inner-side hollow fiber ZIF-8 membrane exhibits good performance for recovering hydrogen.

A facile reactive seeding (RS) method was developed for the preparation of continuous MOF membranes on alumina porous supports, in which the porous support acted as the inorganic source reacting with the organic precursor to grow a seeding layer.

For the first time, a homochiral metal–organic framework membrane was prepared for the enantioselective separation of important chiral compounds, especially chiral drug intermediates, which will allow for the potential development of a new, sustainable and highly efficient chiral separation technique.

Highly-effective sustainable hydrogen production from ethanol and water was achieved in a tubular dense mixed-conducting oxygen permeable membrane reactor, in which water splitting took place at the tube side of the membrane and oxidative steam reforming of ethanol occurred at the shell side simultaneously.

Catalytic membrane reactors which carry out separation and reaction in a single unit are expected to be a promising approach to achieve green and sustainable chemistry with less energy consumption and lower pollution. This article presents a review of the recent progress of dense ceramic catalytic membranes and membrane reactors, and their potential applications in energy and environmental areas. A basic knowledge of catalytic membranes and membrane reactors is first introduced briefly, followed by a short discussion on the membrane materials including their structures, composition and strategies for material development. The configuration of catalytic membranes, the design of membrane reaction processes and the high temperature sealing are also discussed. The performance of catalytic membrane reactors for energy and environmental applications are summarized and typical catalytic membrane reaction processes are presented and discussed. Finally, current challenges and difficulties related to the industrialization of dense ceramic membrane reactors are addressed and possible future research is also outlined.

A facile aerosol deposition approach, which was simulated as feasible by density functional theory (DFT), was applied to synthesize a Prussian Blue (PB) film directly on a Pt electrode surface.

A ferroelectric MOF with a formula [Sr(μ-BDC)(DMF)]∞ (1) was transformed into [Sr(μ-BDC)(CH2Cl2)x]∞ (2) using a solvent exchange approach, where DMF = N,N-dimethylformamide and BDC2− = benzene-1,4-dicarboxylate. The lattice solvents, CH2Cl2 molecules, in 2 were removed by heating to give the solvent-free metal–organic framework [Sr(μ-BDC)]∞ (3) and the crystal-to-crystal transformation is reversible between 1 and 3. The release of DMF molecules from 1 results in the metal–organic framework of [Sr(μ-BDC)]∞ expanding a little along the a- and b-axes. The crystal structure optimizations for 1 and 3 disclosed that the lattice expansion is associated with the alternations of the bond distances and angles in the Sr2+ ion coordination sphere along the a- and b-axes directions. The metal–organic framework 3 collapses at temperatures of more than 600 °C; such an extremely high thermal stability is related to the closed-shell electronic structure of the Sr2+ ion, namely, the coordinate bond between the closed-shell Sr2+ ion and the bridged BDC2− ligands does not have a preferred direction, which is favored for reducing lattice strains and is responsible for the higher thermal stability. The comparative investigations for the dielectric and ferroelectric behaviors of 1 and 3 confirmed that the motion of the polar DMF molecules, but not the [Sr(μ-BDC)]∞ framework, is responsible for the ferroelectric properties of 1.

A three-dimensional NbO-type metal–organic framework (MOF) is composed of paddle-wheel-type dinuclear Cu2 secondary units and 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate (EBTC4−) linkers. Two types of nanometer-sized cavities are formed in this framework with ca. 8.5 Å in diameter for the small one and dimensions of ca. 8.5 × 8.5 × 21.5 Å for the larger and irregular elongated cavity. The guest molecules, H2O, DMF and DMSO, occupy the cavities of the as-prepared MOF crystal (labeled as MOF 1). MOF 2 was obtained by the guest-exchange approach using CH3OH, and the H2O and CH3OH molecules reside in the cavities of 2. Two MOFs show greenish-turquoise color at ambient temperature due to the d–d transition of Cu2+ ions in the framework, and the reversible thermochromic behavior owing to the change of the coordination environment of Cu2+ ions with varying temperatures. The films of 1 and 2 were fabricated on the α-Al2O3 and SiO2 supports by the seeded growth method, displaying similar reversible thermochromic behavior to the corresponding MOFs. This study suggested the possibility of novel thermochromic materials in the rational design of MOFs.

A three-dimensional (3D) microarray of a gold modified electrode with a nanoporous surface was successfully fabricated in this work. The special gold micro/nanostructure possessed an extremely high surface area (ca. 20 times its geometrical area), as well as highly stable and easily chemically modified properties, which could distinctly increase the binding sites for biological probes, facilitate the diffusion profile and enhance the electron transfer. Owing to these advantages, an ultrasensitive biosensor was designed on the porous microarray of the gold modified electrode (PMGE), which realized the simultaneous assay of cancer biomarkers of angiogenin (Ang) and thrombin (Tob). Under optimal experimental conditions, an impressively ultralow detection limit of 0.07 pM for Ang (a linear range from 0.2 pM to 10 nM) and a limit of 20 fM for Tob (a linear range from 50 fM to 5 nM) were obtained. Besides, the fabricated biosensor showed an excellent stability, good reproducibility and a high selectivity towards other biological proteins, which also exhibited promising potential for the application in a real serum sample analysis. Such a micro/nanostructure of gold could have widespread applications in biological sensing and quantitative biochemical analysis.

A single layer Prussian blue (PB) grid was constructed on a Pt substrate using a self-assembly approach with nanosphere lithography in order to create a matrix for the uniform and ordered immobilization of proteins. Enzymes were captured in the cavities of the PB grid with the aid of an alkoxy silane linker, which enabled strong interaction between the silane's alkoxy groups and Pt. Using a low applied potential of −0.1 V vs. Ag/AgCl the as-prepared biosensors exhibited excellent performance in the detection of glucose, lactate and glutamate, indicating the versatile application of this specific PB architecture in the area of biosensors.

Metal–organic frameworks (MOFs) are ideal micro- and mesoporous materials for molecular separation. A defect-free MOF membrane supported on a porous substrate is required for high separation performance, however it is rather difficult to eliminate the micro-defects or intercrystalline gaps in the membranes. In this work, a ZIF-78 membrane was synthesized on a porous ZnO support. The defect formation mechanism in the membrane was illustrated by in situ thermal expansion analysis. A novel strategy was proposed to eliminate not only the macroscopic defects but also the intercrystalline gaps in the membrane by controlling the diffusion of solvent molecules through the channels of the ZIF-78 crystal. The ZIF-78 membrane exhibited high performance in separating H2. The ideal selectivity and mixture separation factor of H2–CO2 are 11.0 and 9.5, respectively. The approach reported in this paper offers an efficient and universal strategy for the facile synthesis of high-quality MOF membranes on porous supports.

High sensitivity and accuracy are strongly required for biosensors due to their special application in the life and health of humans. In order to greatly enhance the above two parameters of the prepared biosensor, the architectures of Prussian blue and Au were purposefully designed. A single layer of PB grid with tight nano-holes was constructed to serve as a mould for the constraint of further Au deposition. Based on the steric hindrance effect, the Au crystal can be pushed towards one direction to in situ form a shape of a micro-cypress. Under a very low operation potential, −0.05 V, this composite film has been confirmed to own excellent abilities of performance enhancement and anti-interference as a glucose biosensor. This synthesis strategy can be expected to provide inspiration for morphology control of materials and high performance development of biosensors.

The morphology of a functional film, especially in the microscale or nanoscale, has been found to be critical for the performance of sensor materials. In this report, two shapes of PB crystals, microcubes and nanomastoids, were simultaneously formed using a self-assembly approach, induced by a weak electric field. This architecture exhibited an ultra-sensitive response in H2O2 detection (1922.3 mA M−1 cm−2). By consideration of the experimental results, a synergistic transmitting mechanism is provided to account for this high sensitivity, or the microcubes can fulfil the role of electron accumulation in electrocatalysis, and nanomastoids will fulfil the role of the main transport of electrons from the film to the Pt surface.

Prussian blue (PB) is considered as a promising material for electrochemical biosensors. However, the PB microstructure, which is essential for biosensor performance, is difficult to control on the electrode surface due to its rapid formation reaction. In this report, the growth of a regular nano-structured PB on the platinum (Pt) electrode surface was realized by an aerosol deposition approach without a template. The morphology of PB could be controlled well via deposition time and temperature, as characterized by cyclic voltammetry (CV), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The cuboid and cubic shapes of PB nano-crystals were formed at 25 and 35 °C, respectively. When the Pt electrode with nano-cubic PB was used to detect hydrogen peroxide, it exhibited a high sensitivity (1163 mA M−1 cm−2) and an excellent anti-interference to ascorbic acid. Our observations suggest that the proposed approach may be used for regular growth of crystals having rapid formation reaction, and the prepared amperometric biosensor will have potential applications in the detection of physiological substances.