What is the method to recover trace Cl ions in hydrofluoric acid?

 

i have tried adding sodium carbonate before evaporation to dryness then recover using ultra pure deionised water. But the result i get is 0 recovery when i measure using ion chromatography.

 

Please help.

you could add dilute silver nitrate, that will "lock up" the Chlorine and present itself as a white PPT.

although silver fluoride can form if you add too much, it`s very soluble in comparison.

 

when you have filtered and isolated your silver chloride, dry this and expose it to strong UV light, silver metal will form and give you back your Cl2.