• Korean Membrane Journal
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• v.1 no.1
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• pp.1-7
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• 1999

Pd-ceramic composite membranes and catalytic membrane reactors(CMR) have been studied for hydrogen and its isotopes (deuterium and tritium) purification and recovery in the fusion reactor fuel cycle. Particularly a closed-loop process has been studied for recovering tritium from tritiated water by means of a CMR in which the water gas shift reaction takes place. The development of the techniques for coating micro-porous ceramic tubes with Pd and Pd/Ag thin layers is described : P composite membranes have been produced by electroless deposition (Pd/Ag film of 10-20 $\mu$m) and rolling of thin metal sheets (Pd and Pd/Ag membranes of 50-70 $\mu$m). Experimental results of the electroless membranes have shown a not complete hydrogen selectivity because of the presence of some defects(micro-holes) in the metallic thin layer. Conversely the rolled thin Pd and Pd/ag membranes have separated hydrogen from the other gases with a complete selectivity giving rise to a slightly larger (about a factor 1.7) mass transfer resistance with respect to the electroless membranes. Experimental tests have confirmed the good performances of the rolled membranes in terms of chemical stability over several weeks of operation. Therefore these rolled membranes and CMR are adequate for applications in the fusion reactor fuel cycle as well as in the industrial processes where high pure hydrogen is required (i.e. hydrocarbon reforming for fuel cell)

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.380-385
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• 2014

Clay-based membranes with submicron pore size were successfully prepared by a simple pressing process using low-cost starting materials(e.g., kaolin (K), bentonite (B), talc (T), and sodium borate). The green bodies were sintered at $1000^{\circ}C$ for 2 h in air. The effect of clay-mineral composition on the flexural strength of clay-based membranes was investigated. The porosity of the clay-based membranes could be controlled within the range of 34 - 42% by adjusting the starting composition. The flexural strength of the low-cost membranes depended on both the porosity and the ${\alpha}$-quartz content. In turn, the porosity and ${\alpha}$-quartz content were affected by the (B+T) /(K+B+T) ratio. The plot of strength relative to this ratio, showed a maximum when the ratio was 0.4. The typical flexural strength of these clay-based membranes (with ratio 0.4) was 28 MPa at 34% porosity.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.59-65
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• 1988

To develop porous glass membranes used for a effective membrane-separation process, porous glasses and glass membranes were prepared from the sodium borosilicate parent glass by the phaseseparation technique and effects of heat-treatment and leaching conditions on their characteristics were investigated. The crack-free glass membranes could be fabricated from the 9.4 Na2-O-30.7 B2O3-59.2 SiO2-0.7 Al2O3(wt%) parent glass by heat-treatment at the lower temperature(550-570$^{\circ}C$) and for longer than 45 hrs for the phase separation, followed by leaching with 3N-HCl＋60% ethylene glycol solution at 90$^{\circ}C$ over 25 hrs. Porous glasses prepared in this work showed large specific surface areas(400㎡/g) and narrow pore size distribution with the mean pore radius of 14${\AA}$ enough for the application as reverse osmosis membranes. The salt-rejection efficiency and product-flux of the glass membranes heat-treated at 570$^{\circ}C$ for 80 hrs were found to be 51.8% and 270cc/㎡. hr, respectively. This result suggests that the porous glass membranes fabricated in this study could be applied for the reverse osmosis process.

• Journal of the Korean Ceramic Society
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• v.29 no.6
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• pp.496-504
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• 1992

Alumina tubes suitable for the support of gas separation membranes have been prepared by the slipcasting technique. These supports have the average pore size of 0.1 ${\mu}{\textrm}{m}$ within the narrow distribution. The sol-gel dipcoating process of nanoparticulate sols is very sensitive to microstructure of the support, and the coating on the inside surface of the tube is found to be more successful than on the outside surface. Nanoparticulate silica sols (0.82 mol/ι) have been synthesized by an interfacial hydrolysis reaction between TEOS and high alkaline water. When coating an alumina tube with these sols, the minimum limits of the particle size and the aging time required for forming the coated gel layer at the given pH are provided. It is optimum to coat the support with less concentrated sols stabilized through aging for the appropriate time (more than 22 days) at the lower pH (pH 2.0) for producing a reproducible crack free thin film coating in composite membranes.

• Journal of the Korean Ceramic Society
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• v.52 no.4
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• pp.269-272
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• 2015

$La_2Ce_2O_7$ and $CeO_2$ membranes were fabricated from the corresponding powders derived from sol-gel process with polyvinyl alcohol binder. These powders and membranes were characterized by XRD, BET, and FE-SEM analysis. Hydrogen and CO gas permeation experiments were performed using Sievert's type equipment. Both fluxes on these membranes were found to decrease with increase of the temperature. This phenomenon was followed by the surface and Knudsen diffusion mechanism. The hydrogen permeability of the $La_2Ce_2O_7$ membrane was found to be $7.27{\times}10^{-5}mol/m^2sPa$, with perm-selectivity of 7.24 at 303 K.

• Journal of the Korean Ceramic Society
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• v.30 no.8
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• pp.678-684
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• 1993

Alumina composite membranes were prepared by chemical vapor deposition and evaporation-oxidation process. For CVD process, deposition was carried out using aluminum-tri-isopropoxide at 35$0^{\circ}C$, 2 torr by heterogeneous reaction, and for evaporation-oxidation process, alumina composite membranes were prepared by evaporation of aluminum and dry oxidation at 80$0^{\circ}C$. As deposition time increases, water flux and N2 gas permeability of the composite membranes prepared by both processes were reduced. Applying gas permeation model, permeability and cracking possibility of top layer were evaluated.

• The Korean Journal of Ceramics
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• v.1 no.4
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• pp.219-223
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• 1995

Ceramic membranes of the supported $TiO_2-CeO_2$ were prepared by dip-coating method on an $\alpha-Al_2O_3$ porous substrate. The mean pore diameter of an alumina support was 0.125 um. The mean particle diameter of $TiO_2-CeO_2$ top layer varied with firing temperature and ranged from 20 to 85 nm. The thermal stability of the composite membranes was studied from their surface microstructure after calcination at $600-900^{\circ}C$. The supported $TiO_2-CeO_2$ composite membranes exhibited much higher heat resistance than the $TiO_2$ membrane.

• Membrane and Water Treatment
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• v.14 no.1
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• pp.11-18
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• 2023

This work addresses the development of microfiltration ceramic membrane from alumina using extrusion method. The membranes were sintered at different temperatures ranging between 1000 and 1300℃. The alumina was characterized with thermogravimetric analysis, particle size distribution, X-ray diffraction, Fourier transform infrared spectrometer and scanning electron microscope analysis. Subsequently, the effect of sintering temperature on the membrane properties such as porosity, flexural strength, and pure water permeability was investigated and optimized for the sintering temperature. It is observed that with increasing sintering temperature, the porosity of the membranes decreases and the flexural strength, and pure water permeability of the membranes increase. The uncoated and coated membranes were compared at constant flux mode of filtration. Under the turbidity solution recirculation alone at 100 NTU, trans-membrane pressure (TMP) of uncoated membrane remained constant when the filtration flux was below 121 Lm^-2 h ^-1 , while the coated membrane was 111 Lm_-2 h ^-1 . Although suction pressure increased more rapidly at higher turbidity, coated membrane filtration showed better removal efficiency of the turbidity.

• Journal of the Korean Ceramic Society
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• v.33 no.6
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• pp.700-708
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• 1996

TiO2 membranes for microfiltration were prepared on $\alpha$-alumina support tube by slurry coating. The coating layer was obtained by flowing TiO2 slip on the inner surface of the alumina support. TiO2 membranes were heat-treated at 9$25^{\circ}C$ for 2 hrs. The thickness of the unsupported membrane was about 10${\mu}{\textrm}{m}$. The mean pore diameter of the membranes were 0.09 and 0.15${\mu}{\textrm}{m}$ respectively and the pure water flux was 900~1,200ι/m2.hr at room temperature and 1 bar. For a possible application of oily wastewater treatement an kerosene/wa-ter emulsion was separated in terms of flux and removal efficiency. In 60 min of operating time the flux of TiO2 membranes was 50~100 ι/m2.hr and removal efficiency was over 97% at 3kgf/cm2 of operating pres-sure and 600 ml/min of flow rate. TiO2 membranes could be recycled by reheat treatments at $600^{\circ}C$ for 2 hrs.

• Membrane Journal
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• v.32 no.2
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• pp.100-108
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• 2022

Among various industries, the textile industry uses the largest amount of water for coloring textiles which leads to a large amount of wastewater containing various kinds of dye. There are various methods for the removal of dye such as flocculation, ozone treatment, adsorption, etc. But these processes are not much successful due to the issue of recycling which enhances the cost. Alternatively, the membrane separation process for the treatment of dye in wastewater is already documented as the best available technique. Polymeric membrane and ceramic membrane are two separate groups of separation membranes. Advantages of ceramic membranes include the ease of cleaning, long lifetime, good chemical and thermal resistance, and mechanical stability. Ceramic membranes can be prepared from various sources and natural materials like clay, zeolite, and fly ash are very cheap and easily available. In this review separation of wastewater is classified into mainly three groups: ultrafiltration (UF), microfiltration (MF), and nanofiltration (NF) process.