Process and system for production of inorganic nanoparticles

DETAILED DESCRIPTION What is claimed is: 1.
A process for production of inorganic nanoparticles, comprising the steps of: a) precipitating the inorganic nanoparticles within a non-continuous micellar phase in a microemulsion containing a non-continuous micellar phase and a continuous phase; and b) concentrating the nanoparticles for recovery by ultrafiltration employing a semipermeable membrane with a pore size selected to retain substantially all the nanoparticles precipitated in the micellar phase, while permeating a permeate stream of the microemulsion continuous phase and the micellar phase not containing precipitated nanoparticles.
2.
The process of claim 1 in which the precipitated nanoparticles have diameters in the range of about 2 nm to 100 nm.
3.
The process of claim 1 in which the precipitated nanoparticles are further processed to yield a final dry product with desired chemical composition.
4.
The process of claim 1 in which the permeate stream is recycled for reuse as a medium for precipitation of additional nanoparticles after replenishment with reagents used for the precipitation reaction and components required to form the micellar phase or the continuous phase of the microemulsion.
5.
The process of claim 4 in which the permeate stream is purified prior to recycle for reuse to remove byproducts produced in the nanoparticle precipitation reaction.
6.
The process of claim 5 in which the permeate stream is purified to remove ionic reaction byproducts.
7.
The process of claim 6 in which the purification process uses adsorption, thermal phase separation, ion exchange, or electrodialysis.
8.
The process of claim 1 in which the ultrafiltration membrane is a ceramic membrane.
9.
The process of claim 8 in which the ceramic membrane is selected from the group consisting of alumina, zirconia, titania, silica, or other ceramic oxides, and combinations thereof.
10.
The process of claim 8 in which the nominal pore size of the membrane is in the range between about 2 nm and 200 nm.
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