Removing Detergent 8

Q. What is best way to remove Detergent 8 from recirculating DI rinse tank.  We currently have 1 activated charcoal canister followed by two mixed resin beds…all at 80C. Do you have a recommended detergent for removing stearic acid (solid form)? One that work with our mixed bed system?

A.  A double sized relative to amount of carbon, carbon bed can do a reasonably good job of removing Detergent 8.  The partition between water and carbon favors the water for Detergent 8 surfactants, so you need excess carbon.  An RO system is better, but of course more expensive. 

Detergent 8 is ion free, so the mixed bed filters do not do much. Among things that will work in your system, Detergent 8 is probably the best thing I have for stearic acid – of course it will work much more effectively if you can get the temperature above the melting point (say up to 170 detg F), but even below that temperature, Detergent 8 should slowly solvate and slightly saponify solid stearic acid – it would not work quickly, but would slowly work away at the solid stearic acid. 

Using water based cleaners on solid stearic acid below the melting point of stearic acid is a slow process. Whatever temperature you can bring will speed things up a little, but there will be a quantum change in the rate of cleaning as you go from 160 deg F to 170 deg F. 

For more information please see the Detergent 8 Technical Bulletin.  Or Download the Detergent 8 MSDS.