The New Energy and Industrial Technology Development Organization (NEDO) started a new NEDO project in 1992. After two years fessibility study, Japan Fine Ceramics Center (JECC) has started research and development study from 1994.
To know the current membrane technology, two missions were send to Europe and the USA last year. The author had chance to join both missions and visited main labolatories in the world which were doing research and development of ceramic membrane.
In this report, 1) the technological subject to develop porous ceramic membrane are focoused, 2) current researches for controlling pore size by sol-gel method, CVD method and zeolite synthesis are introduced briefly, 3) evaluation techniques of membrane and sol particles are introduced shortly, 4) the membrane performance is discussed from the viewpoint of industrial usage and 5) applications of ceramic membrane for carbon dioxide separation.

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Although many studies of inorganic membranes were conducted with ceramics, stainless steel and carbon, pore sizes of membranes were widely distributed. But, along with the advancement in materials development, the pore sizu and its distribution have become small and narrow, respectively. Nowadays, the porous material, especially made of ceramics and glass, can be used as inorganic ultrafiltration and microfiltration membranes. This article discusses present researches and developments on the inorganic membranes for separations in liquid media. Applications of the membranes will also be reviewed

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Development of sol-gel derived porous ceramic membrane is reviewed from the standpoint of gas separation at high temperature. Amorphous silica membranes have attained both high hydrogen selectivity and permeability. However, γ-alumina membranes coated by Yoldas method have pores of 2-10 nm in size, and their hydrogen selectivity is relatively low due to the Knudsen diffusion mechanism. Modification of pores by impregnation of ultrafine particles or chemical vapor deposition improves the selectivity by the size of molecules. The interaction of molecules with pore walls is important for the separation of polar gases. Multicomponent oxide membranes are thermally and chemically stable at high temperature and have appreciable permeation properties.

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Zeolite and molecular sieves are know to be very useful materials for catalysis, ion exchange and adsorption. Recently, great interest has been focused on zeolite membranes due to their uniform pore sizes and resistance to high temperatures. The membranes are also interesting from the standpoint of understanding of growth process of zeolite crystals. As the Al distribution and the change in morphology along the width of membrane reflect the time course of the crystal growth, we can get much information regarding the crystal growth process by analyzing the membrane obtained. Based on the results obtained, it was found that the polycrystalline zeolite membranes are formed through a successive accumulation of zeolite crystals and that during the initial crystallization of zeolite, the zeolite crystals with the high SiO₂/Al₂O₃ ratios are generated.
The liquid separation potential of the polycrystalline silicalite membranes prepared on porous sintered stainless steel and alumina supports was investigated using various alcohol/water mixtures by pervaporation. The membrane showed a high alcohol permselectivity, although there were pores of ca. 1 nm diameter, which were originated from crystal grains, other than intrinsic silicalite pores of ca. 0.6 nm within the membrane. Adsorption experiments of water and alcohols suggest that the high alcohol permselectivity is attributable to the selective sorption of alcohol into the membrane.

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Porous glass membrane is obtained by phase separation method, sol-gel method and crystallized glass method. Phase separation method is most important and sol-gel method is the second. Crystallized glass method is highly potential and will be important in the future. In case of porous glass obtained by sol-gel method, the range of composition is wider. The most important feature of glass membrane compared to the other inorganic membranes is shaping ability.
Pore soze control by phase separation method is carried out by heat treatment process and acid treatment process. In sol-gel method, there are many factors influenced on the pore size, for example, amount of solvent, concentration and kinds of catalyst for hydrolysis. Generally speaking, the pore size control less than 5 nm by phase separation method is very difficult, however, by sol-gel method the control is possible in such a pore size regime.
Surface modification is carried out by impregnation method, reaction with organic compounds including organosilicones and alcohols, vapor deposition method and sol-gel coat. In small pore regime, surface modification controls the pore size at the same time.

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Recently, cross flow micro filtration is used for biomass separation of fermentation broth instead of precoat filtration. Ceramic filter has good performance for many applications. In this review, this performance is reviewed.

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KERASEP, Al₂O₃/TiO₂ based monolithic ceramic membrane modules for MF and UF uses, has been developed by TECH-SEP. It has special features in membrane and support materials, and membrane structure. Market development of KERASEP in Japan has been commenced in water purification application by joining the MAC 21 Project.

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In recent years, the membrane separation technology have been widely made prograss for the food-industry, the medicine-industry and the separation of the various waste water.
Recentry, the membrane separation have been used for the Non-CFC cleaning process and drinking water.
This paper reviews the ceramic membrane separation for the waste water treatment in the Non-CFC cleaning process.

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Comparing to organic membrane, ceramic membrane of high purity Alumina has various superiority such as thermal resistance, chemical resistance, corrosion resistance to solvent and its life span. The most remarkable thing is the high strength and the homogeneous as well as sharpened micro pore distribution which can provide trouble-free high security automatic filtration system. In addition, if necessary, built-in automated back flush and chemical cleaning system offer highly efficient maintenance free system.
History of the ceramic membrane which has above mentioned features is rather short. However, active development of the application facilitates its use in various industrial fields.
This paper reports efficient filitration system for solid and liquid separation using our newly developed ceramic membrane module.

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Permeabilities for pure gases of H₂, He, CH₄, NH₃, H₂O, N₂, N₂, O₂ and CO₂ were measured at trans-membrane pressures up to 0.2 MPa and 303, 423, 523 and 773 K for two types (with small pores and large pores) of composite zirconia-silica membranes coated on the surface of porous ceramic tubes (0.5μm). The composition of the metal-alkoxides solution used successfully in the coating process was Zr (OC₃H₇) ₄ : 3.09, Si (OC₂H₅) ₄ : 7.20, Y (CH₃COO) ₃.4H₂O : 0.21, i-PrOH : 89.50 in molar %.
At low temperatures, with large-and small-pore membranes, the permeation mechanism for H₂O, NH₃ and CO₂ is surface diffusion, and for other gases it is Knudsen flow.
At higher temperature, with a large-pore membrane, the permeation mechanism for H₂O, NH₃, CO, and CH₄ is Knudsen flow, and for other gases it is a combination of Knudsen flow and activated diffusion. With a small-pore membrane, for H₂O it is Knudsen flow, and for all other gases it is activated diffusion.

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