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With more than 30 years of experience in measuring liquid filter retention, CT Associates offers a range of testing options for characterizing your filters.  From membrane coupons to full-size 40” cartridges, we can design a custom retention test to suit your needs. Our filtration experts have been instrumental in assisting in the development of semiconductor filtration testing standards, such as SEMI C79 - GUIDE TO EVALUATE THE EFFICACY OF SUB-15 nm FILTERS USED IN ULTRAPURE WATER (UPW) DISTRIBUTION SYSTEMS.

sample of nanofiltration installed into disc filter housing

However, our test capabilities extend far beyond standardized tests.  We offer a variety of well characterized particle challenge suspensions (i.e. colloidal silica, alumina, zirconium, and polymer microspheres) which cover either wide or relatively monodisperse size ranges.  Filter retention is reported as a function of particle size for particles as small as 4 nm.  Experiments can be performed to investigate the effects of particle loading, filter face velocity, particle feed concentration, liquid pH, and others on filter retention.  

Information we can provide about particle passage, pressure drop across filters and integrity are invaluable in new filter development.  Models made from these retention data can be used to predict field performance and filter lifetime.

Membrane Retention as a Function of Particle Size

filter retention efficiency by nanoparticle size
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