Porous Ceramic Support Research Articles

Development and characterization of an asymmetrical flat microfiltration membrane based on natural phengite clay: Application as a pretreatment for raw seawater reverse osmosis desalination

The work focuses on developing a new asymmetric flat microfiltration membrane using an inexpensive geological material, natural Moroccan phengite clay. The optimal porous ceramic support was prepared by applying the paste casting method and sintering at a low temperature of 1050 °C for 2 h. Secondly, the microfiltration layer was developed by the spin coating method. The layer was then dried and sintered at 850 °C/2h. SEM analysis revealed that the morphological structure of the layer is homogeneous and free from cracks. Furthermore, the microfiltration layer has an average pore size of 1.23 μm, a thickness ranging from 30.3 μm to 31.3 μm, a water permeability of 258.1 L/h.m2.bar, and good chemical stability against corrosion. The performance of the manufactured membrane was evaluated by filtering raw seawater (RSW1 and RSW2) as a potential application for seawater pretreatment before desalination by reverse osmosis. The prepared membrane significantly reduced turbidity concentrations by 98.7 % for RSW1 and 96.8 % for RSW2. The fouling and antifouling mechanisms were also examined. Finally, the preparation cost of the phengite membrane was estimated to be 125 $/m2.

In-situ grown columnar mullite reinforced SiC porous ceramic membrane support with excellent mechanical performance and corrosion resistance: Using TiO2 as the key to form columnar mullite

In this study, in-situ growth of columnar mullite reinforced silicon carbide porous membrane supports were prepared, and the addition of TiO2 helped to reduce the sintering temperature for the anisotropic growth of necked columnar mullite crystals. The synthesis of in situ columnar mullite makes reasonable use of the oxidized silica of silicon carbide, and in turn reduces the loss of the silicon carbide porous membrane support under strong corrosive conditions. The material showed a flexural strength of up to 72.95 MPa, and a water flux of 31612.83 L·m−2·h−1·bar−1 when sintered for 2 h in an air environment at 1250 °C. The flexural strength after corrosion in 20 vol% H2SO4 and 1 wt% NaOH solution (90 °C) exceeded 93 %. This shows that this porous silicon carbide ceramic membrane scaffold has potential applications in the field of water treatment under harsh environments.

A reverse particle grading strategy for design and fabrication of porous SiC ceramic supports with improved strength

A reverse particle grading strategy for design and fabrication of porous SiC ceramic supports with improved strength

Thin polyamide layer cross-linked graphene-oxide based ceramic membranes for efficient separation of the surfactant stabilized oil-in-water emulsions

Two-dimensional (2D) graphene oxide (GO) membranes (GOM) have great potential in separation applications. However, GOMs face two distinct challenges: low flux arising from their tight stacking and instability arising from re-exfoliation of GO sheets in solution. To address these challenges, herein, we report the functionalization of basal planes of GO layers with 2-[2-(3-Trimethoxysilylpropylamino)ethylamino]ethylamine (TSE), followed by transforming them into membranes through a two-step process. In the first step, the functionalized GO sheets were assembled onto the porous ceramic support. At this stage, the interlayer distance between GO sheets was modulated via TSE’s long hydrocarbon chain. Afterward, the free amines of TSE on functionalized GO membranes (fGOM) surface were cross-linked with trimesoyl chloride (TMC) to prepare a hydrophilic thin-layer on top of fGOM (TL-fGOM), further enhancing their stability. Further, TL-fGOMs were tested for oil-in-water-emulsion separation. The increased interlayer distance and the increased surface hydrophilic nature of TL-fGOM offered ultra-high water permeance, 4860 % higher compared to the non-functionalized GOM. Moreover, the separation efficiency of TL-fGOM improved from 37 % of that of ceramic membranes to 99.5 %. Additionally, they showed excellent anti-fouling properties. After exposing the membranes to 500 ppm emulsion for 10 hours in batches, the flux recovery ratio exceeded 90 %. The TL-fGOM in our work demonstrated outstanding performance in purifying oily emulsions containing diesel/toluene/heptane-in-water. All these results revealed that the appropriate functionalization of graphene oxide could assist in forming a thin layer of graphene oxide on the support membranes, offering high separation efficiency and fouling resistance. This approach can be extended further to utilize the graphene oxide membranes for practical applications.

High performance Ce0.8Nd0.2O2-δ-carbonate hollow fiber membrane for high-temperature CO2 separation

Ceramic-carbonate dual phase (CCDP) membrane consisting of oxygen ionic conductor and molten carbonate has potential applications in clean energy delivery as it enabling the direct CO2 separation or capture at the elevated temperatures. The performance of previous CCDP membranes is not ideal either with a low CO2 flux or with a poor operational stability. In the present work, we looked at the CeO2-based oxygen ionic conductor (neodymium doped cerium (NDC)) as the porous ceramic hollow fiber support to form NDC-carbonate hollow fiber membranes. The NDC hollow fiber was fabricated by the combined phase inversion and sintering techniques and the preparation conditions were optimized to better accommodate the carbonate phase and maintain the mechanical stability. The NDC hollow fibers possessed good bending strength, reaching 91.5 MPa upon sintering at 1500 °C. The effects of feed gas composition and sweep flow rates on the CO2 separation performance were carefully investigated. The resultant dual phase hollow fiber membranes exhibited appreciably high CO2 permeation fluxes at temperatures exceeding 800 °C, which was required to activate both conductions of oxygen and carbonate ions. The achieved maximum CO2 flux of the optimized NDC-carbonate hollow fiber membranes was up to 5.08 mL min−1 cm−2 with 50%CO2–50%N2 as the feed gas at 900 °C. At 700 °C, the membrane exhibited a relatively stable CO2 permeation behavior over 120 h and the spent membrane maintained a stable structure. The high flux and good operational stability of the developed membrane make a huge step towards practical applications.

Preparation of high performance porous SiC ceramic membrane support using zeolite and alumina as sintering additives

In-situ reaction bonded porous SiC ceramic membrane supports were successfully synthesized by economical way at 1300 °C in air using waste zeolite residue and alumina as sintering additive. The effects of additives content and sintering temperature on material, mechanical and permeabity properties were carefully investigated. The ceramics prepared at 1300 °C with a 20 % mixture of zeolite residue and alumina obtained with a very high mechanical strength of 114.85 MPa at a porosity of 28.90 vol% and exhibited pure water permeability of 1258 L.h-1.m-2.bar−1. Additionally, the support prepared in this study exhibited good chemical resistance in acid and alkali medium for long periods.The utilization of zeolite residue reduced the sintering temperature for fabrication of membrane support and provided a flexible strategy to control the mechanical performance and water permeability. The filtration and permeation results indicated that SiC membrane support prepared in this study is suitable for various applications, particularly in water treatment.

Effect of La2O3 adding on Properties of SiC Porous Ceramic Support

In this paper, 80-90 grains of SiC as the main raw material, doped La2O3 into the binder composed of potassium feldspar, kaolinite and quartz, and then graphite and activated carbon as pore-making agents to prepare silicon carbide porous ceramic carrier. The effects of doped La2O3 content on the bending strength, porosity and filtration pressure drop of porous SiC ceramics were studied. The results show that the formation of mullite phase and the bending strength of SiC porous ceramics can be improved by adding proper amount of La2O3. Under the sintering temperature of 1300°C for 90 minutes, when the content of La2O3 in the binder is 2.5wt%, the comprehensive performance is the best, the porosity is 21.5%, the bending strength is 53.5MPa, and the filtration pressure drop is low.

Effect of Binder Content on Properties of Cordierite-Mullite Porous Ceramics

In this paper, 70-80 mesh SiC particles were used as the base, and 2.5%MgO was added on the basis of quartz, kaolin and potassium feldspar as the binder. Meanwhile, graphite and activated carbon were added as pore-making agents for SiC porous ceramic supports. At the same time, the amount of binder added was changed under the condition of keeping SiC: pore-making agent 8:1 unchanged. The effects of binder content on flexural strength, filtration pressure drop and porosity of porous SiC ceramics were investigated. The results indicated that the comprehensive properties of SiC porous ceramics can be improved by adding proper amount of MgO. When the content of MgO in the binder was controlled at 2.5% and the amount of binder was 6%, the comprehensive performance of the sample was the best under the conditions of 1300 °C, holding time for 90 minutes and forming pressure of 4/10MPa, respectively. In this case, the flexural strength was 48mpa, the porosity was 25% and the filtration pressure drop was good.

Progress and Perspectives in the Development of Inorganic-Carbonate Dual-Phase Membrane for CO2 Separation

The inorganic-carbonate dual-phase membrane represents a class of dense membranes that are fabricated using diverse support materials, ranging from metals to ceramics. This dual-phase membrane consists of a porous metal or ceramic support with an introduced carbonate phase within the support pores. Compared with polymer and zeolite membranes, inorganic-carbonate dual-phase membranes exhibit exceptional CO2 selectivity at elevated temperatures (>500 °C), making them an ideal choice for high-temperature CO2 separation in power plant systems. The present paper provides a comprehensive overview of the separation principle, significant models, and preparation techniques employed in carbonate dual-phase membranes for CO2 separation. The present study aims to discuss key factors that limit the CO2 permeation performance and stability of membranes, while also exploring the potential applications of dual-phase membranes in various fields. The identification of key challenges in the future development of the carbonate dual-phase membrane has been highlighted in this work. The future trajectory of research and development should be directed toward overcoming these challenges, encompassing the synthesis technology of membranes, balance optimization of membrane structure and performance, modification of physical and chemical properties of molten carbonate, and advancement in high-temperature sealing techniques, as well as exploration of diverse membrane reactors based on carbonate dual-phase membranes for prospective applications.

Fabrication of alumina ceramic membrane supports using LCD 3D printing and titania nanoparticle doping

The integration of 3D printing technology into the production of ceramic membranes has garnered significant interest. Nonetheless, challenges persist in fabricating macroporous supports with both high porosity and strength through 3D printing. In this study, titania nanoparticles were introduced to facilitate the fusion of alumina nanoparticles. This freed the pores occupied by alumina nanoparticles and enhanced the connections between micron-sized alumina particles. Consequently, both the permeability and strength of the ceramic membrane supports were improved. The impact of ceramic slurry composition on photocuring performance, sintering processes, and the addition of titania nanoparticles on the microstructure and properties of the porous ceramic membrane support were investigated. The optimized membrane support featured a pore size of approximately 1.36 µm, achieving a porosity of 42.4% and a pure water permeance of 3700 L·m−2·h−1·bar−1. These findings provide a fundamental groundwork for subsequent endeavors in the development of high-performance ceramic membranes.

High-temperature self-healing behavior of reaction-bonded silicon carbide porous ceramic membrane supports

Reaction-bonded silicon carbide porous ceramics (SCPCs) are increasingly employed as membrane supports for the high-temperature filtration. However, the inevitable expansion of cracks limits their application. Herein, we studied the crack propagation behavior of SCPCs and discovered the commendable self-healing properties at high temperatures. Results show that the optimal healing conditions are 1200 °C for 2 h, which can recover the strength from 41.9% to 88.4%, and maintain the initial pore structure and permeance. This is mainly attributed to the infiltration of the multi-phase oxide melt that healed the cracks rather than the oxidation of SiC. Neck cracks are more prone to healing than surface cracks on SiC particles due to the residual compressive stress and a high proportion of melt volume. Nonetheless, the recovery of residual compressive stress and the crack width constrain the upper limit of strength recovery. These insights lay the groundwork for the high-temperature industrial application of SCPCs.

Effects of Processing Conditions on the Properties of Porous Diatomite Granules Prepared by Sodium Alginate Gelation

The proper application of millimeter-sized spherical porous ceramic supports in catalytic operations relies on their ease of handling, convenient separation, recyclability, high-catalyst-solid loading, and the optimum mass transfer of reactants and products. However, common granulation techniques of spherical carriers entail complex liquid-phase-based processes under severe conditions and the use of toxic or expensive reagents. The present study discusses the manufacturing of porous ceramic granules derived from an inexpensive silica source (diatomite, solid network) and a biopolymer cross-linked by ion exchange (sodium alginate, patterning structure). The results indicated that, with fixed granulation conditions, porous diatomite granules with a sphericity of approximately 0.9 could be successfully obtained by optimization of the diatomite/sodium alginate dispersion to a 30.07 wt.% solid content and 1560 mPa·s viscosity (at ~0.3 s−1). Moreover, the described manufacturing process was proven effective in developing hierarchically porous diatomite granules that were heat-treated at 1200 °C with high sphericity (~0.9), acceptable compressive strength (5.17 ± 0.31 MPa), and porosity features (total porosity: 69.0 ± 2.9%, macropore size: 2.777 μm, mesopore size: 35.34 nm), establishing them as well-matched support materials for either catalytic or adsorption applications.

Incorporation of gallinaceous egg shell waste as an alternative raw material for porous ceramic support

Recycled aggregate from roller compacted concrete (RCD) has become a more popular building material with widespread use in many countries around the world, as the amount of construction and demolition waste produced daily has become an environmental concern. Therefore, the present work aims to analyze the characteristics of the behavior of concrete using recycled aggregate. For the development of the study, a narrative bibliographical review was used, through the deductive method, obtaining a qualitative approach on the behavior of concrete using recycled aggregate. A material produced in large quantities in hatcheries is eggshell, which is difficult to remove and dispose of in large quantities. Concrete was tested for compressive strength at 14 and 28 days. In relation to concrete with treated eggshell waste, the reference concrete mix was expanded; Relative replacement percentages of fine aggregate with eggshell waste (0% to 30%). The results showed that the compressive strength decreased by 30%, with the increase in the percentage of eggshell residue. It is indicating that the mixture was suitable for blocks and slabs.

Effect of SiO2 Adding on Properties of SiC Porous Ceramic Support

In this paper, The binders were prepared with different proportions of potassium feldspar, kaolin and quartz. In order to optimized the performance of SiC porous ceramics, the influence of binders with different content of SiO2 on the bending strength, filtration pressure drop and stomatal rate of porous ceramics were explored. The results show that doping of 10wt% SiO2 in the binder can improve the mechanics performances of SiC porous ceramics. Samples prepared by thermal insulation for 90 minutes at 1300°C had the best comprehensive performance when the adhesive contained 10wt% SiO2. At this time, the porosity was 25.52%, the bending strength was 47.15 MPa, and the filtration pressure drop was comparatively low.

Fabrication of a Zircon Microfiltration Membrane for Culture Medium Sterilization

Multilayer ceramic membranes to be used for bacteria removal by filtration were prepared from ceramic materials. They consist of a macro-porous carrier, an intermediate layer and a thin separation layer at the top. Tubular and flat disc supports were prepared from silica sand and calcite (natural raw materials), using extrusion and uniaxial pressing methods, respectively. Making use of the slip casting technique, the silica sand intermediate layer and the zircon top-layer were deposited on the supports, in this order. The particle size and the sintering temperature for each layer were optimized to achieve a suitable pore size for the deposition of the next layer. Morphology, microstructures, pore characteristics, strength and permeability were also studied. Filtration tests were conducted to optimize the permeation performance of the membrane. Experimental results show that the total porosity and average pore size of the porous ceramic supports sintered at different temperatures within the range (1150-1300 °C), and lie in the ranges of 44-52% and 5-30 μm, respectively. For the ZrSiO4 top-layer, after firing at 1190 °C, a typical average pore size of about 0.3 μm and a thickness of about 70 μm were measured, while water permeability is estimated to a value of 440 lh-1m-2bar-1. Finally, the optimized membranes were tested in the sterilization of a culture medium. Filtration results show the efficiency of the zircon-deposited membranes for bacteria removal; indeed, the growth medium was found to be free of all microorganisms.

Functional ceramic support as an independent catalyst layer for direct liquid fuel solid oxide fuel cells

A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells (SOFCs) running on liquid hydrocarbon fuel. The layer consists of a highly porous Ce_0.9Ca_0.1O_{2−<i>δ</i>} ceramic backbone and active NiMo catalysts, which could be integrated into the conventional Ni metal containing the anode for internal reforming of the hydrocarbon fuel. Compared to conventional catalyst layers sintered on the anodes, this independent catalyst layer could be simply assembled on top of the anode without additional sintering, thereby avoiding the mismatch of the thermal expansion coefficient between the catalyst layer and the anode and improving stability of a single cell. Moreover, a current collector layer could be inserted between the catalyst and the anode to enhance current collection efficiency and electrochemical performance of the single cell. At 750 ℃, the independent catalyst layer displays high activity towards the catalytic decomposition of methanol, and the single cell could achieve the maximum power density of 400–500 mW·cm⁻² in dry methanol. Furthermore, by employing the independent catalyst layer, the single cell offers additional <i>in-situ</i> catalyst regeneration capability under the methanol operation mode. Feeding 10 mL·min⁻¹ air into an anode channel for 5 min is found to be effective to burn out carbon species in the catalyst layer, which reduces the degradation rate of the cell voltage by orders of magnitude from 2.6 to 0.024 mV·h⁻¹ during the operation of 360 h in dry methanol. The results demonstrate the significance of the independent catalyst layer design for direct internal reforming methanol fuel cells.

Novel nickel ceramic filter for hot gas cleanup of tars from syngas

Tars, defined as hydrocarbons having molecular weights above that of benzene, have been considered to be one of the major impurities in syngas preventing largescale commercialization of biomass gasification. Catalytic tar removal has shown the most promise in reforming/eliminating tars compared to physical and thermal techniques. Nickel based catalytic filter was developed using porous ceramic support, which acts both as a particulate filter and tar reformer, resulting in process intensification. The relatively high surface area of the ceramic filter (100 m2/g) makes it an ideal catalyst support. Nickel based ceramic catalysts were prepared using incipient wetness method and evaluated for tar removal effectiveness using naphthalene as a tar simulant. Influence of nickel loading, steam/carbon ratios, and temperatures on steam reforming activity of the catalyst was performed. Promising results were obtained with naphthalene conversions of 76% using a 15 wt% nickel filter over 2 h with very minimal pressure drop across the catalytic filter, offering a promising potential of using catalytic ceramic filters for integrated tar and particulate removal applications.

Valorization potential of coffee grounds waste as a renewable pore-forming agent to produce low-cost porous ceramic support

Every day expressive amounts of coffee grounds waste generated during making the coffee beverage are produced worldwide. The aim of this work was to investigate the valorization potential of the coffee grounds waste as an alternative pore-forming agent to produce porous kaolin-based ceramic supports. For this purpose, kaolin-based ceramic support formulations containing up to 40 mass % of coffee grounds waste were pressed and fired at temperatures ranging from 1000 to 1200 ºC. The sintering behavior and technical properties (linear shrinkage, mass loss, apparent density, mechanical strength, and apparent porosity) have been investigated. The microstructural evolution has been accompanied by scanning electron microscopy (SEM) and 3D-confocal microscopy. The obtained results demonstrated that the coffee grounds waste could serve as a very effective pore-forming agent to produce kaolin-based ceramic support with highly porous structures. Such ceramic supports incorporated with coffee grounds waste exhibited values of apparent porosity within the range of 41.87 % to 70.96 %. This results suggests that the coffee grounds waste, in the range of 10 - 40 mass %, could be a highly promising renewable porogenic material to be valorized to produce low-cost kaolin-based ceramic support with good porosity properties. This new approach could be an innovative alternative for the sustainable use of coffee grounds waste.

Preparation of porous mullite ceramic supports from high alumina fly ash

Preparation of porous mullite ceramic supports from high alumina fly ash

Influence of firing temperature on the ceramic properties of illite-chlorite-calcitic clays

The influence of firing temperature on the ceramic properties of illite-chlorite-calcitic clays has been investigated. Three samples of the same clay deposit have been selected. Weight loss, dimensional changes, water absorption, bulk density, open porosity, flexural and compressive strengths, initial capillary water absorption rate and thermal conductivity have been determined as a function of firing temperature in the range 900-1200 °C with 1 h of soaking time. The microstructures of the fired samples have been examined by SEM and the phase evolution studied by XRD. The water absorption capacity decreased from ∼ 22% at 900 °C/1 h to a maximum of 12% at 1200 °C/1 h with a maximum linear shrinkage of ∼ 2.7%. The open porosities decreased from ∼ 36% at 900 °C/1 h up to ∼ 20% at 1200 °C/1 h as an effect of progressive sintering with higher densification degree of the ceramic bodies. The flexural strength reached a maximum value of ∼ 34 MPa at 1200 °C/1 h. In contrast, the compressive strengths increased by firing up to a maximum of ∼ 114 MPa at 1200 °C/1 h. The thermal conductivity increased slightly as increasing firing temperature with a maximum value of 0.582 W/m·K in samples fired at 1200 °C/1 h. The Ryshkevitch-Duckworth equation was applied and the results indicated that compressive strength is related linearly with open porosity. A linear correlation was found between thermal conductivity and open porosity. The microstructural evolution by SEM indicated that there is a change of the fired samples at 1100 °C as compared to SEM observations at 900 and 1000 °C. There is an increase of contacts between particles and layered structures associated to dehydroxylated clay minerals (illite and chlorite), quartz particles and pores developed by firing. At 1200 °C/1 h, the microstructures have changed associated to the higher degree of vitrification in the fired sample, with consolidation of the material, interparticle and neck contacts with formation of vitrified bridges. The formation of closed and large open pores of several sizes has been achieved by firing. Small particles were observed as a fine precipitation of crystals in the vitrified structures associated to anorthite, hematite and quartz relicts. This change in microstructure allowed deduce that the compressive strength increased upon firing, with maximum values of this ceramic property at 1200 °C. The ceramic bodies were more sintered by firing and the open porosity decreased progressively. Brickmaking is the main application of these fired illite-chlorite calcitic clays. These clays fired at 900–1100 °C, with 1 h of soaking time, could be applied in the fabrication of clay roofing tiles, tiles and even porous ceramic supports with small variations on shrinkage and porosity, good flexural strengths and high compressive strengths. Samples fired at higher temperatures, 1100 °C/1 h, could be applied as ceramic bricks showing a medium porosity (∼ 20%). They show almost the same bulk density when they are fired at lower temperatures (900 °C). Samples fired at higher temperatures (1150–1200 °C/1 h) could be applied as dark ceramic products. This investigation was interesting because a better knowledge of illite-chlorite-calcitic clays applied as ceramic raw materials has been achieved.