Dye Penetrant Removal

NFX Nanofiltration Membrane 
Background
Penetrant testing with fluorescent dyes is an economical way to test for imperfections and defects in non-pourous materials such as metals, plastics, and ceramics.  It’s proven to be an effective method for locating surface defects in many different products. However, the waste solution generated by this process can present problems for meeting discharge regulations.  If this solution can be processed to remove the dye, penetrant inspectors could see a significant cost savings through dye reuse and an increased ability to meet discharge standards.  Synder Filtration’s NFX Nanofiltration membrane was tested for effectiveness in removing yellow fluorescent dye from water.  

Feed Solution, Membrane, and Operation Parameters  
(Table 1) 

Feed Solution  
Material  Fluorescent Dye Penetrant
Dilution factor   100
Membrane   
Type   NFX Nanofiltration Flat Sheet (150-300KD)
NF Standard Operating Parameters   
Pressure (PSI) 110
Temperature (C) 20-25

Results 
A side by side visual comparison of the feed solution and permeate is displayed in image 2 (right). No dye was observed in the permeate after an hour long trial.  These results suggest that Synder’s NFX membrane may be very effective in removing fluorescent penetrant from water.