The technology of the selective precipitation of arsenic from solutions for its detection and isolation

Abstract

This is a technology of the selective precipitation of (AsO4)3− from solutions as the Fe3+ hydroxoarsenate using the FeCl3, NaHCO3 and CH3CO2H. This can be used as a qualitative reaction for arsenic. The dissolving of the Fe3+ and Ag+ arsenates in CH3CO2H in the presence of the CH3CO2Na is discovered. The Fe3+ acetate is stable in water solution without other reagents (it was discovered); and it is stable in CH3CO2H solutions. The arsenic can be isolated using the reactions: Fe3+ hydroxoarsenate + reducing agents, example: Ca(H2PO2)2, as the dark amorphous precipitate (like soot). Then it can be sublimated. This is a safe easy reliable highly sensitive alternative to the Marsh test.