Inorganic nanofiltration membrane comprises macroporous titanium oxide support, intermediate separating layer(s) and top metal oxide separating layer for nanofiltration

摘要

An inorganic nanofiltration membrane comprises a macroporous titanium oxide support, one or more intermediate separating layers and a top separating layer for nanofiltration in metal oxide Preferred Features: The cut threshold is 100-2000 daltons, preferably 800-2000 daltons. The membrane is tubular or planar. The nanofiltration layer has a specific mass of 2-4 g/m<2>, preferably 3 g/m<2> and is made of titanium oxide. The intermediate separating layer is made of a metal oxide, preferably titanium oxide. The intermediate separating layer contains an ultrafiltration layer in metal oxide (preferably titanium oxide or zirconium oxide) deposited on a microfiltration layer in metal oxide (preferably titanium oxide), deposited on the support. The nanofiltration layer is obtained by forming a base by polycondensation of a corresponding metal alcoxide in alcohol in the presence of a gelling agent; deposit of this base on the support or the intermediate separating layer; drying the base to form a gel and fritting the gel thus obtained. Alternatively, the nanofiltration layer is obtained by forming a base by hydrolysis of a corresponding metal alcoxide followed by peptization; deposit of this base on the support or the intermediate separating layer; drying the base to form a gel and fritting the gel thus obtained.