Ceramic Composite Membrane Research Articles

Preparing Sustainable Membranes Made From Zeolite–Smectite for Treating Textile Wastewater and Pulp Industry Wastewater

AbstractLow‐cost separation techniques are crucial for treating wastewater. Developing inexpensive membranes made from natural materials has become a popular research area in recent years. Tubular membranes were produced by adding 10% organic additives to a mixture of 80% zeolite and 10% smectite. New composite ceramic membranes from zeolite and smectite were prepared using the extrusion method to create a plastic paste and characterized using XRD, SEM, EPMA, and FTIR. The impact of sintering temperature (Tsint, 850–950 °C) on membrane properties, such as microstructure, mechanical strength (MS), water permeability, and filtration performance, was investigated. The MS and shrinkage rate increased with Tsint. At 950 °C, the resulting composite membrane exhibited a high MS of over 65 MPa, a relatively low porosity of 30%, appropriate for membrane filtration, and a water permeability of 65 L·h⁻¹·m⁻2·bar⁻¹. When applied to remove pollutants from wastewater, this membrane demonstrated a high color retention of 98.4% from an aqueous Evans blue‐colored solution (Effluent 1). For extensive application to wastewater treatment, this membrane showed a high‐efficiency level for treating real effluent produced by the pulp industry, removing 62.4% of chemical oxygen demand, 36% of hardness, and 82% of color. Finally, an ultrasonic cleaning procedure allowed the restoration of 70% of the initial permeability after four cycles for both effluents. Thanks to the exciting properties offered by these membranes and their competitive cost of less than $ 20·m−2, these membranes are appropriate for treating industrial wastewater.

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

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

Co-sintering fabrication of ceramic whiskers enhanced SiC membranes for high-efficiency dust-laden gas filtration

Application of silicon carbide (SiC) ceramic membrane in industrial dust-containing gas filtration has been widely explored. However, its limited gas permeance and complex sintering process hinder its application. In this work, two types of SiC whisker-reinforced ceramic membranes, namely, whisker ceramic membranes (WCMs) and whisker/particle composite ceramic membranes (WPCMs), were prepared using a co-sintering process. By optimizing the co-sintering temperature and SiC whisker contents, defect-free and uniform ceramic membranes were obtained. The mean pore size of WCMs was 12.2 μm with a gas permeance of ∼ 478.0 m3·m−2·h−1·kPa−1. The WPCMs exhibited a mean pore size of 3.3 μm with a gas permeance of ∼ 288.0 m3·m−2·h−1·kPa−1. SiC whiskers interlaced and connected within membranes, forming a network structure that not only effectively prevented delamination or deformation of the membrane during the co-sintering process but also significantly enhanced the gas permeance of membranes. Additionally, SiC whiskers improved the overall bending strength of membranes and enhanced the rejection of dust particles in the dust-laden gas. The resulting WCMs and WPCMs showed excellent chemical stability and thermal shock resistance. Moreover, the optimized membranes achieved a removal efficiency of 99.99 % for macro (15 μm), micro (2.5 μm), and nano (300 nm) solid particles in the dust-laden gas. This work fabricated high-performance SiC whisker-reinforced membranes that were particularly suitable for gas purification.

Effect of silicon powder dosage on the microstructure and performance of SiC/Si3N4 composite ceramic microfiltration membranes

The SiC/Si3N4 composite ceramic microfiltration membranes were fabricated using the in-situ nitridation process of silicon powder at 1350 °C, utilizing SiC powder and silicon powder as the raw materials. The effects of silicon powder dosage on the phase composition, basic physical properties, pure water flux, pore size distribution, and microstructure of membrane materials were investigated. With an increase in the silicon powder quantity from 5 wt% to 20 wt%, the flexural strength of the membrane materials increased from 6.6 MPa to 42.4 MPa, while the apparent porosity remained stable at 37.0%–39.0 %. The experimental results indicated a substantial correlation between the pore size distribution and the pure water flux. As the average pore size of the ceramic membranes decreased from 463.87 nm to 132.68 nm, the pure water flux gradually decreased from 265.99 L/(m2⋅h⋅bar) to 50.34 L/(m2⋅h⋅bar). The systematic investigation reveals that the Si3N4 binding phase, generated from the in-situ nitriding reaction of silicon powder, is the primary factor responsible for enhancing the mechanical properties of the membrane material. The process of in-situ nitriding silicon powder is accompanied by an increase in volume, which is beneficial in filling and refining the pores. Moreover, the formation of silicon nitride whiskers during the nitriding process can enhance the material's mechanical properties and further divide and refine the pores.

Lithium aluminium titanium phosphate based ceramic composite membrane for selective lithium-ion separation via a scalable membrane-based electrodialysis process

The escalating global demand for lithium necessitates efficient extraction methods, particularly from natural sources such as brine. Herein, we report a novel, thin, and dense functionalised composite ceramic membrane that is employed in conjunction with electrodialysis technology for selective lithium extraction from salt lakes. This membrane exhibits high mechanical strength, low ionic impedance, and high lithium conductivity. The thin functional layer, ~20 μm-thick NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) superionic conductor material, is deposited on high-strength and porous alumina membrane via a facile dip-coating method, providing structural stability for the composite membrane. The preparation and sintering processes of LATP-Al2O3 ceramic composite membrane were systematically studied and precisely controlled to improve its morphology and performance. A membrane-based electrodialysis set-up was designed specifically for lithium extraction demonstrated the remarkable performance of the composite-LATP membrane in separating lithium from magnesium-lithium solutions with a high Mg/Li ratio. The LATP composite membrane effectively reduced the Mg/Li ratio from 40 to 2.1 after three-stage electrodialysis. Moreover, the Li+ recovery reached 77.15% from the feed solution with an estimated power consumption of ~47.6 kWh per 1 kg of lithium carbonate. These findings have significant implications for the development of low-cost and environmentally friendly inorganic membrane separation technologies, which are important for promoting technological innovation in the lithium industry chain.

Fabrication and characterization of ceramic tubular composite membranes using slag waste materials for oily wastewater treatment

In this study, low-cost tubular ceramic membranes were fabricated by using waste slag and natural raw materials in order to decrease the manufacturing carbon footprints. The effects of incorporation of phosphorus slag (PS) and blast furnace slag (BFS) in the mullite-zeolite membrane body were investigated. The structural characteristics of the fabricated membranes were evaluated using X-ray diffraction (XRD), field emission–scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle, porosity and average pore size analyses. Thermal and mechanical stability were studied by thermogravimetric analysis (TGA) and three-point bending test, respectively. The oily wastewater treatment tests revealed that an increase in the slag percentage from 0 to 30% leads to enhancing the permeate flux from 99 l m−2 h−1 to 349 l m−2 h−1 for PS-based tubular membrane and to 244 l m−2 h−1 for BFS-based tubular membrane under 1 bar applied. The chemical oxygen demand (COD) removal percentage of all membranes was reported almost 99% for oily wastewater feed with a COD concentration of 612 mg l−1. In addition, the investigation of membrane fouling mechanisms was carried out using Hermia models indicating that the best correlation with the experimental data is observed for the complete pore blocking model. This study presents experimental foundations aimed at enhancing the performance of affordable slag-based membranes, thus fostering their applicability in engineering contexts.

Eco-Friendly Superhydrophobic Modification of Low-Cost Multi-Layer Composite Mullite Base Tubular Ceramic Membrane for Water Desalination

This study aimed to investigate and develop a cost-effective and superhydrophobic ceramic membrane for direct contact membrane distillation (DCMD) applications. Two types of mullite-based composite membranes were prepared via extrusion and sintering techniques. To create a small and narrow pore diameter distribution on the membrane surface, the dip-coating technique with 1 µm alumina was employed. The hexadecyltrimethoxysilane eco-friendly grafting agent was adopted to modify low-cost multilayer mullite-based composite membranes, transforming them from hydrophilic to superhydrophobic. The prepared membranes were characterized via field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), liquid entire pressure (LEP), contact angle, atomic force microscopy (AFM), porosity, and membrane permeability. The results of the prepared membranes validate the appropriateness of the material for membrane distillation applications. The optimized membrane, with a contact angle of 160° and LEP = 1.5 bar, was tested under DCMD using a 3.5 wt.% sodium chloride (NaCl) synthetic solution and Persian Gulf seawater as a feed. Based on the acquired results, an average permeate flux of 3.15 kg/(m2·h) and salt rejection (R%) of 99.62% were found for the 3.5 wt.% NaCl solution. Moreover, seawater desalination showed an average permeate flux of 2.37 kg/(m2·h) and salt rejection of 99.81% for a 20-h test without any pore wetting. Membrane distillation with a hydrophobic membrane decreased the turbidity of seawater by 93.13%.

Modified ceramic membrane with temperature responsiveness and self-cleaning property for efficient separation and catalysis

Composite membrane that integrating catalytic degradation with membrane separation offers a promising solution for one-step treatment of complex wastewater. However, the challenge of membrane fouling by multi-component pollutants, impedes their broader applications. Herein, building on previous work, temperature responsive polymers are grafted onto a nano-Ag decorated ceramic substrate for enhanced dye removal and anti-fouling property. The grafting process is optimized in terms of reaction temperature (75 ℃), reaction time (4 h), and monomer concentration (VMDMO: 0.01 M, MATE: 0.02 M, DMAEMA: 0.04 M). The morphology of the membrane surface after each modification step is characterized by FESEM. The prepared composite membrane manifests temperature-responsive property. As the temperature rises from 20 °C to 85 °C, the pure water flux of the membrane increases from 68.8 L m-2h−1 to 434.4 L m-2h−1 (0.1 MPa), reflecting a six-fold enhancement. And this temperature response is reversible. In oil-in-dye containing water treatment, the composite membranes demonstrate an oil separation efficiency exceeding 98.0 % and a dye degradation efficiency surpassing 99.0 %. By elevating the ambient temperature, the flux recovery of the composite membrane is 91.2 %, which is much higher than that of the original membrane (58.8 %). This is ascribed to the physical configuration and wettability changes of the grafted polymers at different temperature, which facilitate the release of foulants. This study introduces a novel strategy (surface modification with temperature responsive polymer) for preparing anti-fouling ceramic composite membrane with the function of catalytic degradation of dyes. It would have potential applications in environmental remediation.

Porous Ceramic Metal-Based Flow Battery Composite Membrane.

In metal-based flow battery, membranes significantly impact energy conversion efficiency and security. Unfortunately, damages to the membrane occur due to gradual accumulation of metal dendrites, causing short circuits and shortening cycle life. Herein, we developed a rigid hierarchical porous ceramic flow battery composite membrane with a sub-10-nm-thick polyelectrolyte coating to achieve high ion selectivity and conductivity, to restrain dendrite, and to realize long cycle life and high areal capacity. An aqueous zinc-iron flow battery prepared using this membrane achieved an outstanding energy efficiency of >80%, exhibiting excellent long-term stability (over 1000 h) and extremely high areal capacity (260 mAh cm-2). Low-field nuclear magnetic resonance (NMR) spectroscopy, small-angle X-ray scattering, in situ infrared spectroscopy, solid-state NMR analysis, and nano-computed tomography revealed that the rigid hierarchical pore structures and numerous hydrogen bonding networks in the membrane contributed to the stable operation and superior battery performance. This study contributes to the development of next-generation metal-based flow battery membranes for energy and power generation.

Porous Ceramic Metal‐Based Flow Battery Composite Membrane

AbstractIn metal‐based flow battery, membranes significantly impact energy conversion efficiency and security. Unfortunately, damages to the membrane occur due to gradual accumulation of metal dendrites, causing short circuits and shortening cycle life. Herein, we developed a rigid hierarchical porous ceramic flow battery composite membrane with a sub‐10‐nm‐thick polyelectrolyte coating to achieve high ion selectivity and conductivity, to restrain dendrite, and to realize long cycle life and high areal capacity. An aqueous zinc‐iron flow battery prepared using this membrane achieved an outstanding energy efficiency of >80%, exhibiting excellent long‐term stability (over 1000 h) and extremely high areal capacity (260 mAh cm−2). Low‐field nuclear magnetic resonance (NMR) spectroscopy, small‐angle X‐ray scattering, in situ infrared spectroscopy, solid‐state NMR analysis, and nano‐computed tomography revealed that the rigid hierarchical pore structures and numerous hydrogen bonding networks in the membrane contributed to the stable operation and superior battery performance. This study contributes to the development of next‐generation metal‐based flow battery membranes for energy and power generation.

Compact SiOC ceramic composite nanofiltration membranes by slow dip coating for water purification

In this work, novel silicon oxycarbide (SiOC) ceramic composite nanofiltration membranes with high performance were successfully synthesized at low sintering temperatures by gradual dip-coating approach for the first time. The slow dip-coating process facilitated improved wetting and even spreading of the precursor solution across the substrate. This controlled method ensured the formation of uniform and continuous SiOC ceramic membranes without the introduction of substantial defects or irregularities. Consequently, the systematic approach minimized the occurrence of pinholes, cracks and other structural imperfections in the SiOC ceramic membranes. The synthesis of the SiOC separation layer involved the sintering of polymeric polysilicon as precursor, which caused a lower decomposition temperature in contrast to the conventional method employing silicon carbide powder for sintering. The specific feature enabled a sharp decrease in the sintering temperature which was required for the formation of the separation layer. The prepared SiOC ceramic composite nanofiltration membranes exhibited good permeability with high rejection of dye molecules (>95%) and maintained stable water flux for at least 24 h, showing good long-term stability during cross-flow filtration. This progress provides new approach for the fabrication of compact ceramic nanofiltration membranes with low sintering temperatures, high separation efficiency and enhanced stability.

Retracted: The Influence of Multisensor Fusion Machine Learning on the Controllable Fabrication of MOF (UIO-66)/ZrAl Ceramic Composite Membranes

Retracted: The Influence of Multisensor Fusion Machine Learning on the Controllable Fabrication of MOF (UIO-66)/ZrAl Ceramic Composite Membranes

Flexible crystalline zinc doped silica nanofibers with superior wettability and remediation for oily wastewater

Construction of ceramic fibrous membranes with good mechanical property and separation performance for the remediation of surfactant stabilized emulsions at high-temperature or complex environment is on great demand, yet still a challenge. Herein, the zinc ions doped silica (ZSO) nanofibrous membranes with expectable flexibility and superior selective wettability is prepared via a facile sol–gel electrospinning technique. The doping of zinc ions in silica nanofibers induced the obvious variation in crystalline and surface roughness structure, which were directly relevant to the mechanical properties and wettability of the resultant ZSO nanofibrous membranes. The advantageous features favored the ZSO membranes with excellent surfactant stabilized oil-in-water emulsion separation performance, including the separation efficiency of >98 %, the permeation flux of ∼3900 L m−2 h−1 driven by gravity, outstanding chemical stability, and good reusability within 10 cycles. In addition, the rationally designed micro-/nano-structured composite ceramic fibrous membranes displayed significant improvements on structural stability, mechanical property, and prominent separation performance towards emulsions at high temperature (∼95 °C) and nanoparticle-containing wastewater. The clarification of the relationship among crystalline structure, surface roughness, mechanical properties, and application performance would facilitate the fabrication of filtration materials used in the fields of oil-spill cleanup, seawater destination, and wastewater remediation.

Ceramic membrane composites for highly efficient oil–water separation: a review

This review explores the potential for ceramic membrane composites used in highly efficient oil–water separation while summarizing the characteristics of 10 common ceramic composite membranes.

Ceramic thin-film composite membranes with tunable subnanometer pores for molecular sieving

Ceramic membranes are a promising alternative to polymeric membranes for selective separations, given their ability to operate under harsh chemical conditions. However, current fabrication technologies fail to construct ceramic membranes suitable for selective molecular separations. Herein, we demonstrate a molecular-level design of ceramic thin-film composite membranes with tunable subnanometer pores for precise molecular sieving. Through burning off the distributed carbonaceous species of varied dimensions within hybrid aluminum oxide films, we created membranes with tunable molecular sieving. Specifically, the membranes created with methanol showed exceptional selectivity toward monovalent and divalent salts. We attribute this observed selectivity to the dehydration of the large divalent ions within the subnanometer pores. As a comparison, smaller monovalent ions can rapidly permeate with an intact hydration shell. Lastly, the flux of neutral solutes through each fabricated aluminum oxide membrane was measured for the demonstration of tunable separation capability. Overall, our work provides the scientific basis for the design of ceramic membranes with subnanometer pores for molecular sieving using atomic layer deposition.

Development of mesoporous ceramic membranes of diatomite/TiO2/Nb2O5 nanocomposites for the treatment of contaminated water

There is an urgent need for low cost and efficient methods for the treatment of contaminated water; in this regard the combination of natural minerals for the preparation of sieves is of special interest. The aim of this work is to develop mesoporous composite ceramic membranes using low-cost minerals: diatomite, niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) powders. The multilayer samples were prepared by the tape casting technique. Initially, four tapes with different relative amounts of the minerals are prepared (diatomite %/ TiO2 %/ Nb2O5 %); the samples are A (1/0/0), B (0.9/0.1/0), C (0.9/0.05/0.05) and D (0.9/0/0.1). These tapes were cut, arranged in a multilayer, pressed, and calcined at 500 °C in presence of air. Then, these multilayers were sintered at 1200 °C in presence of argon to form the ceramic membranes (CM): CM-A, CM-B, CM-C and CM-D. A fifth ceramic membrane CM-E was prepared by combining tapes B and D. The X-ray diffraction characterization identified the phases cristobalite, quartz, anatase, rutile, and H-Nb2O5. The three-point bending test demonstrated a 225 % increase in strength after the incorporation of Nb2O5 and TiO2 particles to the diatomite matrix. For instance, the CM-A and CM-C membranes showed 4.28 and 13.90 MPa, respectively. The monolithic ceramic membranes showed high surface area, the BET analysis indicated a narrowing of pore sizes when are added Nb2O5 and TiO2 particles to diatomite; and showed surface areas of up to 6.161 m2 g-1. The composites presented band gap energies in the range of 3.19–3.70 eV. The ability of the ceramic membranes in the photodegradation of methylene blue in aqueous solutions was tested, the results showed a degradation of up to 87.3 % of the dye.

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

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

A robust superhydrophobic-superoleophilic PDMS/Al2O3/CM composite ceramic membrane: Stability, efficient emulsified oil/water separation, and anti-pollution performance

To address the issue of membrane fouling and low separation efficiency of ceramic membrane (CM) commonly encountered in oil/water separation, the implementation of a robust superhydrophobic coating on the surface of CM represents a viable and efficacious strategy. This study presented a facile approach for the fabrication of a durable superhydrophobic-superoleophilic composite coating on the surface of CM by the in-situ growth of needle-shaped alumina (Al2O3) followed by the impregnation of a polydimethylsiloxane (PDMS) coating. Various characterization techniques, such as FESEM, XPS, CLSM, bubble point porometer, contact angle etc. were used to characterize the microstructure, surface composition, pore size distribution, and surface characteristics of the PDMS/Al2O3/CM. The mechanical, chemical, and thermal stability were evaluated by means of sandpaper abrasion, tape peeling, immersion tests including organic solvent, acid, and base solutions, and heat treatment. The separation performance, anti-pollution property, and reusability of the modified CM were evaluated by oil/water mixture and water-in-oil emulsion. And the oil/water separation model and anti-fouling mechanism was also elaborated. The results indicated that a homogeneous needle Al2O3 cluster with a micro/nano dual-scale hierarchical roughness was grown on the surface of the CM, and the further introduction of PDMS gave the modified CM excellent superhydrophobicity with a water contact angle (WCA) of ∼160° and a water rolling angle (WOA) of 7.6°. The PDMS/Al2O3/CM composite membrane exhibited remarkable capability in segregating oil/water mixtures, including emulsified water-in-oil. The separation efficiency remained above 99 %, even after 15 cycles of separation. This study presents a simple technique for fabricating a robust superhydrophobic coating onto the Al2O3-based CM surface, which exhibits the potential for application to other ceramic membrane substrates. And the anticipated outcome of this developing is a broad spectrum of industrial applications for emulsified oil/water purification.

Insight into the design of a Ti3C2 MXene/Ti4O7 composite ceramic membrane boosts the electrocatalytic activity for 1,4-dioxane electro-oxidation

Efficient refractory organic compound (ROC) removal through Ti4O7 ceramic membrane in electrochemical advanced oxidation processes (EAOPs) requires high electrochemical reactivity and stability. Herein, we report on the synthesis and properties of Ti3C2 MXene-doped Ti4O7 ceramic membranes (Ti3C2@Ti4O7) using a spark plasma sintering system, after employing density functional theory calculations to design the electrocatalyst. Doping with Ti3C2 MXene resulted in interfacial Ti–O–Ti chemical bond formation, which greatly improved the electronic structure and the generation of hydroxyl radicals (•OH). Compared with pristine Ti4O7, the charge-transfer resistance of Ti3C2@Ti4O7 decreased from 59.09 to 4.21 Ω, and the •OH generation rate enhanced 2.3 − 2.6-fold. Ti3C2@Ti4O7 could effectively remove 1,4-Dioxane from natural groundwater, and the residual 1,4-Dioxane concentration met the requirements for drinking water. Our study provides a proof-of-concept demonstration using Ti3C2 MXene to manufacture a doped Ti4O7 ceramic membrane for effective ROC removal. The theoretical predictions from this study can inspire novel electrocatalyst designs for EAOPs.

Chitosan-modified fly-ash/kaolin ceramic membrane for enhancing FOG-water separation performance

Ceramic membranes with efficient construction can save costs and simplify the wastewater treatment process. The price of raw materials and the amount of energy used during the sintering process are the two key factors that affect the final cost of ceramic membranes. This work used kaolin and fly ash recovered from power plants as the support membrane and chitosan as selective layer of composite ceramic membranes. Rigid alumina particles were added to the supports to bring them into alignment with the sintering temperature of the fly-ash/kaolin support. Additionally, the chitosan layer coating increased the supports' bending strength. By simple surface coating, chitosan with different molecular weights was spread over the fly-ash/kaolin supports. The membranes' average pore size radius and porosity were 20 nm and 49%, respectively. The oil removal rate was over 99.8% and the stable permeance was close to 20.5 Lm2h1 when treating oil-water emulsions with 400 mg/L oil content. This is most likely because of the super-hydrophilic performance of kaolin and the electrostatic repulsion between the membrane and oil droplets. The fabricated membranes also demonstrated high antifouling performance by enhancing FRR up to 88% and reduced the reversible fouling ratio. This study suggests that modified membrane has great potential for practical application in oily wastewater treatment.