Pre-concentration and separation of vanadium on Amberlite IRA-904 resin functionalized with porphyrin ligands

Among several methods, enrichment techniques based on sorption onto chelating resins seem convenient, rapid and capable to achieve a high concentration factor. Amberlite IRA-904 resin modified with tetrakis (p-carboxyphenyl) porphyrin (TCPP) was used to pre-concentrate vanadium species. Several parameters, such as sorption capacity of the chelating resin, pH for retention of V(IV) and V(V), volume of sample and eluent, were evaluated. Both vanadium species sorbed on TCPP-modified resin were eluted by use of 2 M nitric acid and determined by atomic absorption spectrometry. The recovery values were >94% and pre-concentration factor of 110 was obtained. For speciation studies, CDTA was added to the sample for complexing vanadium(IV), which was not retained on the microcolumn. The proposed method was examined for reference standard material (TM-25.2) and river water sample.