Ceramic membranes formed from nanoparticles: an environmental technology

Membranes, which are used commercially for the last 50 years, are more and more employed since the last ten years. They can be used at the industrial level for liquid, solid or gaseous separations down to the microscopic scale. In spite of all the advantages of the ceramic membranes (chemical stability, resistance in organic solvents, extreme pH, of high pressures) with regard to organic membranes, their development has been quite long mainly due to strong synthesis difficulties and high cost to produce crack and defect free membranes. Metallic oxides nanoparticles show themselves perfectly adapted to synthesize ceramic membranes, with various advantages. Their small size allows to realize membranes with very reduced sizes of pores. Moreover their high surface reactivity may enable the synthesis of reactive membranes or even catalytic membranes. This paper presents some examples of nanoparticles used in the synthesis of ceramic membranes like the Ferroxane (R) nanoparticles obtained by reaction of an iron base mineral and acetic acid. All the characterizations indicate that the obtained membranes are adapted to the ultrafiltration. But the most important point concerns their surface reactivity allowing them to sorb certain soluble pollutants. Furthermore they appear as candidates of choice for fuel cells.