Ultra pure water filtration

DETAILED DESCRIPTION The present invention includes removing particles from high purity water for use in electronics applications using multichannel monolithic cross-flow ceramic membranes.
It has been found through empirical testing that the advantages of using multichannel monolithic cross-flow 200 .
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ceramic membranes in this filtration include an ability to run hot and to put ozone in the ceramic membrane filter for particle purification purposes.
An unexpected result was observed in complete particle rejection together with no leaching of the membrane element.
The ceramic membrane ultrafilter's particle retentive characteristics of the present invention, because of its rigid construction, are unaffected by pressure pulses.
This is a definite advantage.
Prior to the demonstration of this technology, it was believed that significant particle counts could be removed, but that the resulting product stream would contain ions formed from leaching out of aluminum.
It was found from work conducted by an independent analytical laboratory that the product water stream contained acceptable TOC, together with high particle removal.
The independent analytical laboratory can detect aluminum at 0.
007 parts per trillion, and none was observed at or above this detection limit.
The demonstration was unexpected and surprising in the result of no aluminum leaching because aluminum or alumina in contact with water will leach out aluminum ions at least in the parts per billion range.
Such leaching is particularly expected in the case of ultra pure water.
Although not certain, it may be that the mechanism operating here is attributable to the sintered nature of the membrane.
The novel filtration technology of the present invention is run with very high recoveries per pass such that water is in contact with the ceramic membrane over a high residence time.
This aspect of the process makes the unexpected result of no leaching of the ceramic membrane elements even more surprising.
The ceramic membrane ultrafilter's pore size was found to be unaffected by ozone independent of ozone concentration or length of exposure