A Novel Porous Ceramic Membrane Supported Monolithic Cu-Doped Mn–Ce Catalysts for Benzene Combustion

Porous ceramic membranes (PCMs) are considered as an efficient hot gas filtration material in industrial systems. Functionalization of the PCMs with high-efficiency catalysts for the abatement of volatile organic compounds (VOCs) during dust elimination is a promising way to purify the industrial exhaust gases. In this work, we prepared PCMs (porosity: 70%) in a facile sintering process and integrated Cu-doped Mn–Ce oxides into the PCMs as monolithic catalysts by the sol–gel method for benzene oxidation. Through this method, the catalysts are dispersed evenly throughout the PCMs with excellent adhesion, and the catalytic PCMs provided more active sites for the reactant gases during the catalytic reaction process compared to the powder catalysts. The physicochemical properties of PCMs and catalytic PCMs were characterized systematically, and the catalytic activities were measured in total oxidation of benzene. As a result, all the prepared catalytic PCMs exhibited high catalytic activity for benzene oxidation. Significantly, the monolithic catalyst of Cu0.2Mn0.6Ce0.2/PCMs obtained the lowest temperature for benzene conversion efficiency of 90% (T90) at 212 °C with a high gaseous hourly space velocity of 5000 h−1 and showed strong resistance to high humidity (90 vol.%, 20 °C) with long-term stability in continuous benzene stream, which is caused by abundant active adsorbed oxygen, more surficial oxygen vacancy, and lower-temperature reducibility.

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Mass Transfer in Tubular Ceramic Membranes for Polluted Water Treatment - Numerical Simulation

Diffusion Foundations ◽

10.4028/www.scientific.net/df.20.16 ◽

2018 ◽

Vol 20 ◽

pp. 16-33 ◽

Cited By ~ 1

Author(s):

J. Saraiva de Souza ◽

S. José dos Santos Filho ◽

Severino Rodrigues de Farias Neto ◽

A.G. Barbosa de Lima ◽

H.A. Luma Fernandes Magalhães

Keyword(s):

Mass Transfer ◽

Water Treatment ◽

Produced Water ◽

Ceramic Membrane ◽

Porous Ceramic ◽

Ceramic Membranes ◽

Numerical Results ◽

Polluted Water ◽

Separation Processes ◽

Water Separation

Innovative technologies are needed to attend the increasingly strict requirements for produced water treatment, since most of the separation processes are limited to particles larger than 10 μm. Separation processes using ceramic membranes are attracting great interest from academic and industrial community. Nevertheless, few studies, especially numerical, regarding the inorganic membrane’s application for the polluted water separation have been reported. In the present work, therefore, a study of fluid-flow dynamics for a laminar regime in porous tubes (tubular porous ceramic membrane) has been performed. The mass, momentum and mass transport conservation equations were solved with the aid of a structured mesh using ANSYS CFX commercial package. The velocity of local permeation was determined using the resistance in series model. The specific resistance of the polarized layer was obtained by Carman-Kozeny equation. The numerical results were evaluated and compared with the results available in the literature, where by a good agreement with each other was found. The numerical results, obtained by the proposed shell and tubular membrane separation module, indicate that there is facilitation of mass transfer and hence a reduction in the thickness of the polarized boundary layer occurs.

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Preparation, characterization and catalytic properties of yttrium-zirconium-pillared montmorillonite and their application in supported Ce catalysts

Clay Minerals ◽

10.1180/claymin.2015.050.2.05 ◽

2015 ◽

Vol 50 (2) ◽

pp. 211-219 ◽

Cited By ~ 5

Author(s):

Bo Xue ◽

Hongmei Guo ◽

Lujie Liu ◽

Min Chen

Keyword(s):

Catalytic Activity ◽

Ethyl Acetate ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Active Sites ◽

Industrial Applications ◽

High Catalytic Activity ◽

Total Oxidation ◽

Pillared Montmorillonite

AbstractA new yttrium-zirconium-pillared montmorillonite (Y-Zr-MMT), was synthesized, characterized and used as a Ce catalyst support. The Y-Zr-MMT is a good support for dispersing cerium active sites and it is responsible for the high activity in the total oxidation of acetone, toluene and ethyl acetate. The Y-Zr-MMT shows greater advantages than the conventional alumina/cordierite honeycomb supports such as large specific surface area, lower cost and easier preparation. Catalytic tests demonstrated that Ce/Y-Zr-MMT (Ce loading 8.0%) was the most active, with the total oxidation of acetone, toluene and ethyl acetate being achieved at 220, 300 and 220°C, respectively. The catalyst displayed better activity for the oxidation of acetone and ethyl acetate than a conventional, supported Pd-catalyst under similar conditions. The special structure of the yttrium-doped zirconium-pillared montmorillonite can strengthen the interaction between the CeO2 and Zr-MMT support and improve the dispersion of the Ce particles, which enhances the catalytic activity for the oxidation of VOCs. The new catalyst, 8.0%Ce/Y-Zr-MMT, could be promising for industrial applications due to its high catalytic activity and low cost. The support and the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET specific surface area measurements.

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Preparation of a High-Performance Porous Ceramic Membrane by a Two-Step Coating Method and One-Step Sintering

Applied Sciences ◽

10.3390/app9010052 ◽

2018 ◽

Vol 9 (1) ◽

pp. 52 ◽

Cited By ~ 3

Author(s):

Zhiwen Hu ◽

Yulong Yang ◽

Qibing Chang ◽

Fengli Liu ◽

Yongqing Wang ◽

...

Keyword(s):

High Performance ◽

Ceramic Membrane ◽

Porous Ceramic ◽

Ceramic Membranes ◽

High Viscosity ◽

Solid Content ◽

Low Viscosity ◽

Coating Method ◽

One Step ◽

Hole Defects

Hole defects and uneven membrane thicknesses can lead to poor performance, especially in the separation stability of ceramic membranes. This paper uses a one-step sintering method, which avoids hole defects and uneven membrane thicknesses, for the preparation of high-performance and defect-free ceramic membranes. For this purpose, two kinds of ceramic membrane slurry with high or low viscosities were prepared by alumina particles, as raw materials. Both the effects of the two coating process with a one-step coating method for low-viscosity slurry, and the two-step coating method with a high viscosity flush after a low viscosity coating, on the surface properties of a ceramic membrane, were studied in detail. The result shows that the properties of ceramic membranes can be improved by a two-step coating method, with a high viscosity flush after a low viscosity coating, A high-performance and defect-free ceramic membrane was obtained by one-step sintering at 1450 °C for 2 hr with 7 wt % solid content and a coating time of 11 s.

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Fabrication, Optimization, and Performance of a TiO2 Coated Bentonite Membrane for Produced Water Treatment: Effect of Grafting Time

Membranes ◽

10.3390/membranes11100739 ◽

2021 ◽

Vol 11 (10) ◽

pp. 739

Author(s):

Mohamad Izrin Mohamad Esham ◽

Abdul Latif Ahmad ◽

Mohd Hafiz Dzarfan Othman

Keyword(s):

Produced Water ◽

Ceramic Membrane ◽

Average Pore Size ◽

Pure Water ◽

Sol Gel ◽

Water Flux ◽

Ceramic Membranes ◽

Average Pore ◽

Pure Water Flux ◽

And Performance

The main problem usually faced by commercial ceramic membranes in the treatment of produced water (PW) is low water flux even though ceramic membrane was well-known with their excellent mechanical, thermal, and chemical properties. In the process of minimizing the problem faced by commercial ceramic membranes, titanium dioxide (TiO2) nanocomposites, which synthesized via a sol-gel method, were deposited on the active layer of the hydrolysed bentonite membrane. This paper studied the influence of grafting time of TiO2 nanocomposite on the properties and performance of the coated bentonite membranes. Several characterizations, which are Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray Spectroscopy (EDX), contact angle, porosity, and average pore size, were applied to both pristine and coated bentonite membranes to compare the properties of the membranes. The deposition of TiO2 nanoparticles on the surface of the coated bentonite membranes was successfully confirmed by the characterization results. The pure water flux performance showed an increment from 262.29 L h−1 m−² bar−1 (pristine bentonite membrane) to 337.05 L h−1 m−² bar−1 (Ti-Ben 30) and 438.33 L h−1 m−² bar−1 (Ti-Ben 60) as the grafting time increase but when the grafting time reached 90 min (Ti-Ben 90), the pure water flux was decreased to 214.22 L h−1 m−² bar−1 which is lower than the pristine membrane. The oil rejection performance also revealed an increase in the oil rejection performance from 95 to 99%. These findings can be a good example to further studies and exploit the advantages of modified ceramic membranes in PW treatment.

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Separation Performance of Nanostructured Ceramic Membranes: Analytical Model Development

Journal of Non-Equilibrium Thermodynamics ◽

10.1515/jnet-2018-0013 ◽

2018 ◽

Vol 43 (3) ◽

pp. 245-253 ◽

Cited By ~ 1

Author(s):

Mashallah Rezakazemi ◽

Saeed Shirazian

Keyword(s):

Analytical Model ◽

Ceramic Membrane ◽

Porous Ceramic ◽

Model Development ◽

Ceramic Membranes ◽

Hydrogen Gas ◽

Separation Performance ◽

Diffusivity Coefficient ◽

Predictive Tool ◽

Nanostructured Ceramic

AbstractNanostructured ceramic membranes have shown considerable separation performance. In this work, an analytical model is developed to evaluate the separation performance of porous ceramic membranes in gas separation applications. The model takes into account three layers, i. e., (1) active layer, (2) interlayer, and (3) support layer. For estimation of sorption at the interface of feed stream and membrane, the partition coefficient model was used and the unsteady-state conservation of mass equation coupled to molecular models of the diffusivity coefficient was used to predict the permeation of penetrant hydrogen gas through a ceramic membrane. It was observed that the model can be readily applied to other systems of interest as a predictive tool.

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Characterization and application of ceramic membranes prepared from Algerian kaolin

Cerâmica ◽

10.1590/0366-69132019653762671 ◽

2019 ◽

Vol 65 (376) ◽

pp. 554-561

Author(s):

M. Aissat ◽

S. Hamouda ◽

N. Bettahar ◽

B. J. Abu Tarboush ◽

A. Bahmani

Keyword(s):

Ceramic Membrane ◽

Sol Gel ◽

Slip Casting ◽

Rejection Rate ◽

Ceramic Membranes ◽

Raw Material ◽

Casting Technique ◽

Thin Film Layer ◽

Film Layer ◽

Membrane Type

Abstract In this study, a new ceramic membrane type was used for the filtration of colored water. The membrane was prepared from local Algerian kaolin KT2 of Milia-type. The choice of this raw material was dictated by its natural abundance, to form the macroporous support prepared by the slip casting technique. A functional thin film layer (with a pore size of about 0.2 μm) produced by the sol-gel method was deposited on the support to reduce the porosity. A detailed study was conducted because of the importance of this layer and the improvement which brought to the filtration process. Ceramic membranes were tested for the removal of bromophenol red (BR) under a filtration pressure of 3 bar and a duration of 2 h of treatment. The results revealed a rejection rate of 100% for BR, especially after the addition of the inorganic layer. The material was characterized by DTA, TGA, XRD and SEM. The retention and the permeability of BR were also studied.

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Mesostructured Anatase TiO2 for Visible Light and UV Photocatalysis With Confinement Effect and Semiconductor Coupling

Journal of Solar Energy Engineering ◽

10.1115/1.2969803 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 5

Author(s):

Florence Bosc ◽

André Ayral ◽

Nicolas Keller ◽

Valérie Keller

Keyword(s):

Visible Light ◽

Partial Pressure ◽

Active Sites ◽

Reaction Rate ◽

High Efficiency ◽

Flow Reactor ◽

Sol Gel ◽

Confinement Effect ◽

Tio2 Anatase ◽

Photogenerated Charge Separation

Hexagonal and cubic mesostructured TiO2 anatase were synthesized by a templating sol-gel method using triblock copolymers as structuring agents, and used as photocatalysts for providing geometrical assistance to a photocatalytic reaction. The visible light and UV photocatalytic removal of gas-phase concentrated toluene (110ppm) within an annular flow-reactor was used as a tool to evidence the benefit to use mesostructured photocatalysts. The coupling of low amounts of WO3 with mesostructured anatase led to high efficiency using visible light and UV activation. The highly positive effect of WO3 on the toluene removal efficiency was attributed to the coupling between TiO2 and WO3 semiconductors, leading to an improved photogenerated charge separation and thus a weaker charge recombination. The hypothesis of a confinement effect of the reactants inside the mesostructured photocatalyst was put forward to explain the photocatalytic performances obtained under visible light and UV activation. This confinement effect would be based on the inner partial pressure concept. It consists of an increase in the partial pressure of the reactants next to the active sites inside the nanometric cavities of the ordered structure, while the apparent macroscopic partial pressures, outside the mesostructure, would remain unchanged. According to a traditional reaction rate law, such an increase results in the increase in the reaction rate. The photon-assisted reaction could be considered as “structure-assisted,” the geometrical assistance being provided by the surrounding ordered TiO2 walls of the mesostructure.

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Fabrication and Characterization of Ice Templated Membrane Supports from Portland Cement

Membranes ◽

10.3390/membranes10050093 ◽

2020 ◽

Vol 10 (5) ◽

pp. 93

Author(s):

Amanmyrat Abdullayev ◽

Paul H. Kamm ◽

Maged F. Bekheet ◽

Aleksander Gurlo

Keyword(s):

High Temperature ◽

Portland Cement ◽

Ceramic Membrane ◽

Porous Ceramic ◽

Ceramic Membranes ◽

Fabrication Process ◽

Transmembrane Pressure ◽

Hydration Reaction ◽

Membrane Thickness ◽

Membrane Fabrication

Porous ceramic membranes for aqueous microfiltration and ultrafiltration processes suffer from the high-costs of material and processing. The latter is mainly due to the high-temperature sintering step. In this work, cement-based membrane supports from ultrafine Portland cement are studied as a low-cost alternative to traditional oxidic ceramic supports. An environmentally friendly freeze-casting fabrication route is applied for the fabrication of porous membrane supports. Cement membrane supports are becoming mechanically stabile after hydration reaction of cement with water, which does not require any high-temperature sintering step as in a conventional ceramic membrane fabrication process. This fabrication route, which is sintering-free, decreases the cost and environmental impact of the membrane fabrication process by eliminating extra energy consumption step during sintering. The Archimedes method, scanning electron microscopy (SEM), micro-computed tomographic (µCT), and mercury porosimetry characterize the membrane supports in respect to open porosity, pore size distribution, morphology, and connectivity. The flexural strength of the 3 mm thick membranes is in the range from 1 to 6 MPa, as obtained by the ring-on-ring tests. The obtained membrane supports possess porosity in the range between 48 and 73% depending on fabrication conditions (cooling rate and the solid content, as determined by Archimedes method enabling water flux in the range between 79 and 180 L/(h·m2) at 0.5 bar transmembrane pressure difference and 3 mm membrane thickness.

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