Synthesis of hafnia powders and nanofiltration membranes by sol-gel process

Hafnia nanofiltration membranes were prepared by sol-gel process from hafni um 1-methoxy-2 propoxide via colloidal route. This original molecular precu rsor has been synthesized and characterized by H-1 NMR, mass spectroscopy, infrared and elemental analysis. Its peptization revealed to be the most ef ficient method to provide a highly reactive powder at a low sintering tempe rature. The porous volume variation and the pore diameter distribution of t he hafnia powder have been studied as a function of the sintering temperatu re and the TGA, DTA and dilatometry study are reported. The membrane sinter ed at 450 degrees C exhibited a defect-free texture with a cut-off equals t o 420 Daltons and pore diameters equal to 1.9 nanometers.