Comparison of sorption of electrochemically generated V(IV) and V(V) onto selective sorbent

Reduction of V(V) to V(IV) was performed at carbon felt cathode at a constant potential of - 1500 mV vs. Ag/AgCl. Adsorption of vanadium species onto the sorbent Purolite D 4123 was investigated in the pH range 2.5 to 5. V(V) was efficiently adsorbed throughout pH range studied, whereas V(IV) was barely adsorbed at pHs of 2.5 to 3.5 and it was re-oxidized to V(V) at higher pHs. In column experiments, V(V) was strongly adsorbed . V(IV) broke through the column readily and reached the inlet concentration within 60 BV. Desorption was carried out with combination of 1 M HCl and 1M NaOH, consequently, and the total vanadium recovery was about 100 %.